Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of po...Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of polo-like kinase 1(PLK1)in BRCA and the corresponding clinical information were extracted from TCGA and GEO databases.PLK1 expression was validated in diverse breast cancer cell lines by quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting.Single sample gene set enrichment analysis(ssGSEA)was performed to evaluate immune infiltration in the BRCA microenvironment,and the random forest(RF)and support vector machine(SVM)algorithms were used to screen for the hub infiltrating cells and calculate the immunophenoscore(IPS).The RF algorithm and COX regression model were applied to calculate survival risk scores based on the PLK1 expression and immune cell infiltration.Finally,a prognostic nomogram was constructed with the risk score and pathological stage,and its clinical potential was evaluated by plotting calibration charts and DCA curves.The application of the nomogram was further validated in an immunotherapy cohort.Results:PLK1 expression was significantly higher in the tumor samples in TCGA-BRCA cohort.Furthermore,PLK1 expression level,age and stage were identified as independent prognostic factors of BRCA.While the IPS was unaffected by PLK1 expression,the TMB and MATH scores were higher in the PLK1-high group,and the TIDE scores were higher for the PLK1-low patients.We also identified 6 immune cell types with high infiltration,along with 11 immune cell types with low infiltration in the PLK1-high tumors.A risk score was devised using PLK1 expression and hub immune cells,which predicted the prognosis of BRCA patients.In addition,a nomogram was constructed based on the risk score and pathological staging,and showed good predictive performance.Conclusions:PLK1 expression and immune cell infiltration can predict post-immunotherapy prognosis of BRCA patients.展开更多
BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinas...BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinase 1(PLK1)is activated in the late G2 phase of the cell cycle and is required for entry to mitosis.Interestingly,PLK1 is overexpressed in many HCC patients and is highly associated with poor clinical outcome.Baculoviral inhibitor of apoptosis repeatcontaining 5(BIRC5)is also highly overexpressed in HCC and plays key roles in this malignancy.AIM To determine the expression patterns of PLK1 and BIRC5,as well as their correlation with p53 mutation status and patient clinical outcome.METHODS The expression patterns of PLK1 and BIRC5,and their correlation with p53 mutation status or patient clinical outcome were analyzed using a TCGA HCC dataset.Cell viability,cell apoptosis,and cell cycle arrest assays were conducted to investigate the efficacy of the PLK1 inhibitors volasertib and GSK461364 and the BIRC5 inhibitor YM155,alone or in combination.The in vivo efficacy of volasertib and YM155,alone or in combination,was assessed in p53-mutated Huh7-derived xenograft models in immune-deficient NSIG mice.RESULTS Our bioinformatics analysis using a TCGA HCC dataset revealed that PLK1 and BIRC5 were overexpressed in the same patient subset and their expression was highly correlated.The overexpression of both PLK1 and BIRC5 was more frequently detected in HCC with p53 mutations.High PLK1 or BIRC5 expression significantly correlated with poor clinical outcome.PLK1 inhibitors(volasertib and GSK461364)or a BIRC5 inhibitor(YM155)selectively targeted Huh7 cells with mutated p53,but not HepG2 cells with wild-type p53.The combination treatment of volasertib and YM155 synergistically inhibited the viability of Huh7 cells via apoptotic pathway.The efficacy of volasertib and YM155,alone or in combination,was validated in vivo in a Huh7-derived xenograft model.CONCLUSION PLK1 and BIRC5 are highly co-expressed in p53-mutated HCC and inhibition of both PLK1 and BIRC5 synergistically compromises the viability of p53-mutated HCC cells in vitro and in vivo.展开更多
In order to investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1)...In order to investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine (BrdU) labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate (IR) by vinorebline (NVB) was determined by MTF assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups (P〈0.05). Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.展开更多
AIM:To investigate the role of polo-like kinase 1 (PLK1) as a therapeutic target for hepatocellular carcinoma (HCC).METHODS:PLK1 gene expression was evaluated in HCC tissue and HCC cell lines.Gene knockdown with short...AIM:To investigate the role of polo-like kinase 1 (PLK1) as a therapeutic target for hepatocellular carcinoma (HCC).METHODS:PLK1 gene expression was evaluated in HCC tissue and HCC cell lines.Gene knockdown with short-interfering RNA (siRNA) was used to study PLK1 gene and protein expression using real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting,and cell proliferation using 3-(4,5-dim ethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2(4-sulf ophenyl)-2H-tetrazolium (MTS) and bromodeoxyuridine (BrdU) assays.Apoptosis was evaluated using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay,and caspase-inhibition assay.Huh-7 cells were transplanted into nude mice and co-cultured with PLK1 siRNA or control siRNA,and tumor progression was compared with controls.RESULTS:RT-PCR showed that PLK1 was overexpressed 12-fold in tumor samples compared with controls,and also was overexpressed in Huh-7 cells.siRNA against PLK1 showed a reduction in PLK1 gene and protein expression of up to 96% in Huh-7 cells,and a reduction in cell proliferation by 68% and 92% in MTS and BrdU cell proliferation assays,respectively.There was a 3-fold increase in apoptosis events,and TUNEL staining and caspase-3 assays suggested that this was caspase-independent.The pan-caspase inhibitor Z-VAD-FMK was unable to rescue the apoptotic cells.Immnofluorescence co-localized endonuclease-G to fragmented chromosomes,implicating it in apoptosis.Huh-7 cells transplanted subcutaneously into nude mice showed tumor regression in siPLK1-treated mice,but not in controls.CONCLUSION:Knockdown of PLK1 overexpression in HCC was shown to be a potential therapeutic target,leading to apoptosis through the endonuclease-G pathway.展开更多
In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and...In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and development of PLK-1 inhibitors.展开更多
BACKGROUND Diabetic retinopathy(DR)is a major ocular complication of diabetes mellitus,leading to visual impairment.Retinal pigment epithelium(RPE)injury is a key component of the outer blood retinal barrier,and its d...BACKGROUND Diabetic retinopathy(DR)is a major ocular complication of diabetes mellitus,leading to visual impairment.Retinal pigment epithelium(RPE)injury is a key component of the outer blood retinal barrier,and its damage is an important indicator of DR.Receptor for activated C kinase 1(RACK1)activates protein kinase C-ε(PKC-ε)to promote the generation of reactive oxygen species(ROS)in RPE cells,leading to apoptosis.Therefore,we hypothesize that the activation of RACK1 under hypoxic/high-glucose conditions may promote RPE cell apoptosis by modulating PKC-ε/ROS,thereby disrupting the barrier effect of the outer blood retinal barrier and contributing to the progression of DR.AIM To investigate the role and associated underlying mechanisms of RACK1 in the development of early DR.METHODS In this study,Sprague-Dawley rats and adult RPE cell line-19(ARPE-19)cells were used as in vivo and in vitro models,respectively,to explore the role of RACK1 in mediating PKC-εin early DR.Furthermore,the impact of RACK1 on apoptosis and barrier function of RPE cells was also investigated in the former model.RESULTS Streptozotocin-induced diabetic rats showed increased apoptosis and upregulated expression of RACK1 and PKC-εproteins in RPE cells following a prolonged modeling.Similarly,ARPE-19 cells exposed to high glucose and hypoxia displayed elevated mRNA and protein levels of RACK1 and PKC-ε,accompanied by an increases in ROS production,apoptosis rate,and monolayer permeability.However,silencing RACK1 significantly downregulated the expression of PKC-εand ROS,reduced cell apoptosis and permeability,and protected barrier function.CONCLUSION RACK1 plays a significant role in the development of early DR and might serve as a potential therapeutic target for DR by regulating RPE apoptosis and barrier function.展开更多
BACKGROUND Radiotherapy stands as a promising therapeutic modality for colorectal cancer(CRC);yet,the formidable challenge posed by radio-resistance significantly undermines its efficacy in achieving CRC remission.AIM...BACKGROUND Radiotherapy stands as a promising therapeutic modality for colorectal cancer(CRC);yet,the formidable challenge posed by radio-resistance significantly undermines its efficacy in achieving CRC remission.AIM To elucidate the role played by microRNA-298(miR-298)in CRC radio-resistance.METHODS To establish a radio-resistant CRC cell line,HT-29 cells underwent exposure to 5 gray ionizing radiation that was followed by a 7-d recovery period.The quantification of miR-298 levels within CRC cells was conducted through quantitative RT-PCR,and protein expression determination was realized through Western blotting.Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and proliferation by clonogenic assay.Radio-induced apoptosis was discerned through flow cytometry analysis.RESULTS We observed a marked upregulation of miR-298 in radio-resistant CRC cells.MiR-298 emerged as a key determinant of cell survival following radiation exposure,as its overexpression led to a notable reduction in radiation-induced apoptosis.Intriguingly,miR-298 expression exhibited a strong correlation with CRC cell viability.Further investigation unveiled human dual-specificity tyrosine(Y)-regulated kinase 1A(DYRK1A)as miR-298’s direct target.CONCLUSION Taken together,our findings underline the role played by miR-298 in bolstering radio-resistance in CRC cells by means of DYRK1A downregulation,thereby positioning miR-298 as a promising candidate for mitigating radioresistance in CRC.展开更多
Polo-like kinase 1(Plk1),a well-characterized member of serine/threonine kinases Plk family,has been shown to play pivotal roles in mitosis and cytokinesis in eu-karyotic cells.Recent studies suggest that Plk1 not onl...Polo-like kinase 1(Plk1),a well-characterized member of serine/threonine kinases Plk family,has been shown to play pivotal roles in mitosis and cytokinesis in eu-karyotic cells.Recent studies suggest that Plk1 not only controls the process of mitosis and cytokinesis,but also,going beyond those previously described functions,plays critical roles in DNA replication and Pten null prostate cancer initiation.In this review,we briefly summarize the functions of Plk1 in mitosis and cytokinesis,and then mainly focus on newly discov-ered functions of Plk1 in DNA replication and in Pten-null prostate cancer initiation.Furthermore,we briefly introduce the architectures of human and mouse pros-tate glands and the possible roles of Plk1 in human prostate cancer development.And finally,the newly chemotherapeutic development of small-molecule Plk1 inhibitors to target Plk1 in cancer treatment and their translational studies are also briefly reviewed.展开更多
Background Expression of polo-like kinase 1 (Plk1) is elevated in lung cancer and has been proposed as having prognostic value and related to resistance to chemotherapy and radiation. In addition, Plk1 has several f...Background Expression of polo-like kinase 1 (Plk1) is elevated in lung cancer and has been proposed as having prognostic value and related to resistance to chemotherapy and radiation. In addition, Plk1 has several functions in mitotic progression. In this study, the authors investigated t he effect of Plk1 depletion on cell cycle progression and proliferation in A549 cells, a lung cancer cell line.Methods A recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells. Reverse transcription-polymerase chain reaction and Western blot were used to examine Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine (BrdU) labelling. Cell cycle and apoptosis were examined by flow cytometry. Expression of α-tubulin was detected by immunofluorescence, and the inhibition rate (IR) by chemotherapeutic agents was determined by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl-tetrazolium bromide assay.Results After transfection into A549 cells, pcDNA3-Plk1 reduced Plk1 mRNA by 46.75% for 24 hours and by 61.84% for 48 hours. Plk1 protein was significantly decreased simultaneously (P<0.05). Abnormal morphological changes of cells and growth inhibition were observed in pcDNA3-Plk1 transfected groups. The BrdU labelling index was 25.59% 48 hours after transfection, which was significantly lower than that of the control groups (P<0.05). Forty-eight hours after transfection, there showed absence of microtubule polymerization and spindle abnormalities in staining for α-tubulin. A549 cells showed a strong G 2/M arrest and apoptosis 72 hours post transfection. IR of vinorelbine in pcDNA3-Plk1 transfected groups was significantly higher than that of the other groups (P<0.05, respectively).Conclusions Plk1 depletion interferes with spindle formation, induces cell cycle arrest and apoptosis, and consequently inhibits cell proliferation in A549 cells. Moreover, it sensitizes lung cancer cells to chemotherapy.展开更多
Polo-like kinase(PLK1) has been identified as a potential target for cancer treatment.Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harb...Polo-like kinase(PLK1) has been identified as a potential target for cancer treatment.Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harbors a regulatory domain, the Polo box domain(PBD), which has a key regulatory function for kinase activity and substrate recognition. We report on 3-bromomethylbenzofuran-2-carboxylic acid ethyl ester(designated: MCC1019) as selective PLK1 inhibitor targeting PLK1 PBD. Cytotoxicity and fluorescence polarization-based screening were applied to a library of 1162 drug-like compounds to identify potential inhibitors of PLK1 PBD. The activity of compound MC1019 against the PLK1 PBD was confirmed using fluorescence polarization and microscale thermophoresis.This compound exerted specificity towards PLK1 over PLK2 and PLK3. MCC1019 showed cytotoxic activity in a panel of different cancer cell lines. Mechanistic investigations in A549 lung adenocarcinoma cells revealed that MCC1019 induced cell growth inhibition through inactivation of AKT signaling pathway, it also induced prolonged mitotic arrest—a phenomenon known as mitotic catastrophe, which is followed by immediate cell death via apoptosis and necroptosis. MCC1019 significantly inhibited tumor growth in vivo in a murine lung cancer model without affecting body weight or vital organ size, and reduced the growth of metastatic lesions in the lung. We propose MCC1019 as promising anti-cancer drug candidate.展开更多
AIM: To investigate the effects of polo-like kinase-1 (PLK1) antisense phosphorothioate oligodeoxynucleotide (ASODN) on apoptosis and cell cycle of human colon cancer cell line 5W480.METHODS: After SW480 colon cancer ...AIM: To investigate the effects of polo-like kinase-1 (PLK1) antisense phosphorothioate oligodeoxynucleotide (ASODN) on apoptosis and cell cycle of human colon cancer cell line 5W480.METHODS: After SW480 colon cancer cells were transfected with PLK1 ASODN, Northern and Western blot analyses were used to examine PLK1 gene expression in cancer cells. We studied apoptosis using terminal uridine deoxynucleotidyl nick end labeling. Apoptosis and cell cycle of SW480 cells were examined by fluorescence-activated cell sorter scan.RESULTS: The levels of PLK1 mRNA and protein were greatly inhibited by PLK1 ASODN in SW480 cancer cells transfected with PLK1 ASODN. Apoptosis index (AI) induced PLK1 ASODN in a time- and dose-dependent manner.Results from FLM showed that sub-2N DNA content of transfected cancer cells was significantly increased and arrested at G2/M compared with control groups.CONCLUSION: PLK1 ASODN can induce apoptosis of human colon cancer cell line SW480.展开更多
AIM: To elucidate the role of overexpressed polo-like kinase1 (PLK1) in hepatocellular carcinoma (HCC). METHODS: We prospectively collected clinicopathological, immunohistochemical and semi-quantitative reverse transc...AIM: To elucidate the role of overexpressed polo-like kinase1 (PLK1) in hepatocellular carcinoma (HCC). METHODS: We prospectively collected clinicopathological, immunohistochemical and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) data from 135 HCC patients undergoing successful hepatectomy. The correlations between PLK1 mRNA expression and clinicopathologic variables were analyzed by Mann-Whitney U test. Prognostic factors were identified by univariate and multivariate analyses. RESULTS: Immunohistochemical results showed over-expression of PLK1 was mainly found in tumor tissues compared with tumor-free tissue. A similar mRNA result was obtained by semi-quantitative RT-PCR. A total of 111 samples were positive for PLK1 mRNA expression. The positive expression was correlated with venous invasion, tumor nodules and Edmondson grade. Furthermore, 1, 3, 5-year survival rates in the positive expression group were significantly lower than the negative control group. Multivariate analysis showed that positive PLK1 expres-sion was an independent risk factor for HCC. CONCLUSION: PLK1 could be a potential biomarker for diagnosis and therapy for HCC.展开更多
Polo-like kinase 1(Plk1),a member of a family of serine/threonine kinases,is an attractive target for the development of anticancer drugs because it is involved in the regulation of cell-cycle progression and cytokine...Polo-like kinase 1(Plk1),a member of a family of serine/threonine kinases,is an attractive target for the development of anticancer drugs because it is involved in the regulation of cell-cycle progression and cytokinesis.This kinase provides two pockets for developing Plk1 inhibitors:the N-terminal catalytic domain(NCD)and the polo-box domain(PBD).For both of the two pockets,some natural products were identified as Plk1 inhibitors and some synthetic Plk1 inhibitors were developed by mimicking ATP and phosphopeptides,natural products binding to NCD and PBD respectively.This article not only reviews the progression of Plk1 inhibitors binding to these two pockets,but also discusses diversity evolution and jump in the process of drug development using Plk1 inhibitors as examples and how they impact on drug design and pharmacophore modeling.展开更多
Polo-like kinase 1(PLK1) plays an important role in many cell-cycle-related events. At G2/Mtransition, PLK1 contributes to the activation of cyclinB/Cdc by phosphorylation of Cdc25C, centrosome functional maturation...Polo-like kinase 1(PLK1) plays an important role in many cell-cycle-related events. At G2/Mtransition, PLK1 contributes to the activation of cyclinB/Cdc by phosphorylation of Cdc25C, centrosome functional maturation, bipolar spindle formation. In later stage of mitosis, PLK1 is involved in regulating components of the anaphase-promoting complex (APC) for mitotic exit and in the execution of cytokinesis. Moreover, recent reports have shown that PLK1 is involved in both G2 and mitotic DNA damage checkpoints. When G2/M DNA damage occurs, PLK1 activity is suppressed and cell cycle arrests to repair the damaged DNA. So far, the deregulated expression of PLK1 has been detected in many types of human tumors and PLK1 is considered as a novel prognostic marker for several tumors.展开更多
Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB le...Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.展开更多
BACKGROUND The role of Tousled-like kinase 1(TLK1)in in gastric cancer(GC)remains unclear.AIM To investigate the expression,biological function,and underlying mechanisms of TLK1 in GC.METHODS We measured TLK1 protein ...BACKGROUND The role of Tousled-like kinase 1(TLK1)in in gastric cancer(GC)remains unclear.AIM To investigate the expression,biological function,and underlying mechanisms of TLK1 in GC.METHODS We measured TLK1 protein expression levels and localized TLK1 in GC cells and tissues by western blot and immunofluorescence,respectively.We transfected various GC cells with lentiviruses to create TLK1 overexpression and knockdown lines and established the functional roles of TLK1 through in vitro colony formation,5-ethynyl-2`-deoxyuridine,and Transwell assays as well as flow cytometry.We applied bioinformatics to elucidate the signaling pathways associated with TLK1.We performed in vivo validation of TLK1 functions by inducing subcutaneous xenograft tumors in nude mice.RESULTS TLK1 was significantly upregulated in GC cells and tissues compared to their normal counterparts and was localized mainly to the nucleus.TLK1 knockdown significantly decreased colony formation,proliferation,invasion,and migration but increased apoptosis in GC cells.TLK1 overexpression had the opposite effects.Bioinformatics revealed,and subsequent experiments verified,that the tumor growth factor-beta signaling pathway was implicated in TLK1-mediated GC progression.The in vivo assays confirmed that TLK1 promotes tumorigenesis in GC.CONCLUSION The findings of the present study indicated that TLK1 plays a crucial role in GC progression and is,therefore,promising as a therapeutic target against this disease.展开更多
基金funded by the Natural Science Foundation of Higher Education Institutions of Auhui Province(Grant No.KJ2021A0352)the Research Fund Project of Anhui Medical University(Grant No.2020xkj236)Applied Medicine Research Project of Hefei Health Commission(Grant No.HWKJ2019-172-14).
文摘Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of polo-like kinase 1(PLK1)in BRCA and the corresponding clinical information were extracted from TCGA and GEO databases.PLK1 expression was validated in diverse breast cancer cell lines by quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting.Single sample gene set enrichment analysis(ssGSEA)was performed to evaluate immune infiltration in the BRCA microenvironment,and the random forest(RF)and support vector machine(SVM)algorithms were used to screen for the hub infiltrating cells and calculate the immunophenoscore(IPS).The RF algorithm and COX regression model were applied to calculate survival risk scores based on the PLK1 expression and immune cell infiltration.Finally,a prognostic nomogram was constructed with the risk score and pathological stage,and its clinical potential was evaluated by plotting calibration charts and DCA curves.The application of the nomogram was further validated in an immunotherapy cohort.Results:PLK1 expression was significantly higher in the tumor samples in TCGA-BRCA cohort.Furthermore,PLK1 expression level,age and stage were identified as independent prognostic factors of BRCA.While the IPS was unaffected by PLK1 expression,the TMB and MATH scores were higher in the PLK1-high group,and the TIDE scores were higher for the PLK1-low patients.We also identified 6 immune cell types with high infiltration,along with 11 immune cell types with low infiltration in the PLK1-high tumors.A risk score was devised using PLK1 expression and hub immune cells,which predicted the prognosis of BRCA patients.In addition,a nomogram was constructed based on the risk score and pathological staging,and showed good predictive performance.Conclusions:PLK1 expression and immune cell infiltration can predict post-immunotherapy prognosis of BRCA patients.
基金Supported by National Science and Technology Major Project,No.2018ZX10732-202-004Tianjin Science and Technology Plan Project,No.17JCYBJC26100 and No.19ZXDBSY00030.
文摘BACKGROUND Hepatocellular carcinoma(HCC),often diagnosed at advanced stages without curative therapies,is the fifth most common malignant cancer and the second leading cause of cancer-related mortality.Polo-like kinase 1(PLK1)is activated in the late G2 phase of the cell cycle and is required for entry to mitosis.Interestingly,PLK1 is overexpressed in many HCC patients and is highly associated with poor clinical outcome.Baculoviral inhibitor of apoptosis repeatcontaining 5(BIRC5)is also highly overexpressed in HCC and plays key roles in this malignancy.AIM To determine the expression patterns of PLK1 and BIRC5,as well as their correlation with p53 mutation status and patient clinical outcome.METHODS The expression patterns of PLK1 and BIRC5,and their correlation with p53 mutation status or patient clinical outcome were analyzed using a TCGA HCC dataset.Cell viability,cell apoptosis,and cell cycle arrest assays were conducted to investigate the efficacy of the PLK1 inhibitors volasertib and GSK461364 and the BIRC5 inhibitor YM155,alone or in combination.The in vivo efficacy of volasertib and YM155,alone or in combination,was assessed in p53-mutated Huh7-derived xenograft models in immune-deficient NSIG mice.RESULTS Our bioinformatics analysis using a TCGA HCC dataset revealed that PLK1 and BIRC5 were overexpressed in the same patient subset and their expression was highly correlated.The overexpression of both PLK1 and BIRC5 was more frequently detected in HCC with p53 mutations.High PLK1 or BIRC5 expression significantly correlated with poor clinical outcome.PLK1 inhibitors(volasertib and GSK461364)or a BIRC5 inhibitor(YM155)selectively targeted Huh7 cells with mutated p53,but not HepG2 cells with wild-type p53.The combination treatment of volasertib and YM155 synergistically inhibited the viability of Huh7 cells via apoptotic pathway.The efficacy of volasertib and YM155,alone or in combination,was validated in vivo in a Huh7-derived xenograft model.CONCLUSION PLK1 and BIRC5 are highly co-expressed in p53-mutated HCC and inhibition of both PLK1 and BIRC5 synergistically compromises the viability of p53-mutated HCC cells in vitro and in vivo.
文摘In order to investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine (BrdU) labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate (IR) by vinorebline (NVB) was determined by MTF assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups (P〈0.05). Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.
基金Supported by The National University of Singapore Grants,No.R-172-000-001-731 and No.R-172-000-024-731
文摘AIM:To investigate the role of polo-like kinase 1 (PLK1) as a therapeutic target for hepatocellular carcinoma (HCC).METHODS:PLK1 gene expression was evaluated in HCC tissue and HCC cell lines.Gene knockdown with short-interfering RNA (siRNA) was used to study PLK1 gene and protein expression using real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting,and cell proliferation using 3-(4,5-dim ethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2(4-sulf ophenyl)-2H-tetrazolium (MTS) and bromodeoxyuridine (BrdU) assays.Apoptosis was evaluated using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay,and caspase-inhibition assay.Huh-7 cells were transplanted into nude mice and co-cultured with PLK1 siRNA or control siRNA,and tumor progression was compared with controls.RESULTS:RT-PCR showed that PLK1 was overexpressed 12-fold in tumor samples compared with controls,and also was overexpressed in Huh-7 cells.siRNA against PLK1 showed a reduction in PLK1 gene and protein expression of up to 96% in Huh-7 cells,and a reduction in cell proliferation by 68% and 92% in MTS and BrdU cell proliferation assays,respectively.There was a 3-fold increase in apoptosis events,and TUNEL staining and caspase-3 assays suggested that this was caspase-independent.The pan-caspase inhibitor Z-VAD-FMK was unable to rescue the apoptotic cells.Immnofluorescence co-localized endonuclease-G to fragmented chromosomes,implicating it in apoptosis.Huh-7 cells transplanted subcutaneously into nude mice showed tumor regression in siPLK1-treated mice,but not in controls.CONCLUSION:Knockdown of PLK1 overexpression in HCC was shown to be a potential therapeutic target,leading to apoptosis through the endonuclease-G pathway.
文摘In this paper,the biological function of PLK-1,the correlation between PLK-1 and tumors,and the latest research progress on PLK-1 inhibitors under study are reviewed,in order to provide references for the research and development of PLK-1 inhibitors.
基金Supported by National Natural Science Foundation of China,No.82260211Key Research and Development Project in Jiangxi Province,No.20203BBG73058Chinese Medicine Science and Technology Project in Jiangxi Province,No.2020A0166.
文摘BACKGROUND Diabetic retinopathy(DR)is a major ocular complication of diabetes mellitus,leading to visual impairment.Retinal pigment epithelium(RPE)injury is a key component of the outer blood retinal barrier,and its damage is an important indicator of DR.Receptor for activated C kinase 1(RACK1)activates protein kinase C-ε(PKC-ε)to promote the generation of reactive oxygen species(ROS)in RPE cells,leading to apoptosis.Therefore,we hypothesize that the activation of RACK1 under hypoxic/high-glucose conditions may promote RPE cell apoptosis by modulating PKC-ε/ROS,thereby disrupting the barrier effect of the outer blood retinal barrier and contributing to the progression of DR.AIM To investigate the role and associated underlying mechanisms of RACK1 in the development of early DR.METHODS In this study,Sprague-Dawley rats and adult RPE cell line-19(ARPE-19)cells were used as in vivo and in vitro models,respectively,to explore the role of RACK1 in mediating PKC-εin early DR.Furthermore,the impact of RACK1 on apoptosis and barrier function of RPE cells was also investigated in the former model.RESULTS Streptozotocin-induced diabetic rats showed increased apoptosis and upregulated expression of RACK1 and PKC-εproteins in RPE cells following a prolonged modeling.Similarly,ARPE-19 cells exposed to high glucose and hypoxia displayed elevated mRNA and protein levels of RACK1 and PKC-ε,accompanied by an increases in ROS production,apoptosis rate,and monolayer permeability.However,silencing RACK1 significantly downregulated the expression of PKC-εand ROS,reduced cell apoptosis and permeability,and protected barrier function.CONCLUSION RACK1 plays a significant role in the development of early DR and might serve as a potential therapeutic target for DR by regulating RPE apoptosis and barrier function.
基金This study was reviewed and approved by the Experimental Animal Ethics Committee of the First Affiliated Hospital of Guangxi Medical University(Approval No.2023-E386-01).
文摘BACKGROUND Radiotherapy stands as a promising therapeutic modality for colorectal cancer(CRC);yet,the formidable challenge posed by radio-resistance significantly undermines its efficacy in achieving CRC remission.AIM To elucidate the role played by microRNA-298(miR-298)in CRC radio-resistance.METHODS To establish a radio-resistant CRC cell line,HT-29 cells underwent exposure to 5 gray ionizing radiation that was followed by a 7-d recovery period.The quantification of miR-298 levels within CRC cells was conducted through quantitative RT-PCR,and protein expression determination was realized through Western blotting.Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and proliferation by clonogenic assay.Radio-induced apoptosis was discerned through flow cytometry analysis.RESULTS We observed a marked upregulation of miR-298 in radio-resistant CRC cells.MiR-298 emerged as a key determinant of cell survival following radiation exposure,as its overexpression led to a notable reduction in radiation-induced apoptosis.Intriguingly,miR-298 expression exhibited a strong correlation with CRC cell viability.Further investigation unveiled human dual-specificity tyrosine(Y)-regulated kinase 1A(DYRK1A)as miR-298’s direct target.CONCLUSION Taken together,our findings underline the role played by miR-298 in bolstering radio-resistance in CRC cells by means of DYRK1A downregulation,thereby positioning miR-298 as a promising candidate for mitigating radioresistance in CRC.
文摘Polo-like kinase 1(Plk1),a well-characterized member of serine/threonine kinases Plk family,has been shown to play pivotal roles in mitosis and cytokinesis in eu-karyotic cells.Recent studies suggest that Plk1 not only controls the process of mitosis and cytokinesis,but also,going beyond those previously described functions,plays critical roles in DNA replication and Pten null prostate cancer initiation.In this review,we briefly summarize the functions of Plk1 in mitosis and cytokinesis,and then mainly focus on newly discov-ered functions of Plk1 in DNA replication and in Pten-null prostate cancer initiation.Furthermore,we briefly introduce the architectures of human and mouse pros-tate glands and the possible roles of Plk1 in human prostate cancer development.And finally,the newly chemotherapeutic development of small-molecule Plk1 inhibitors to target Plk1 in cancer treatment and their translational studies are also briefly reviewed.
文摘Background Expression of polo-like kinase 1 (Plk1) is elevated in lung cancer and has been proposed as having prognostic value and related to resistance to chemotherapy and radiation. In addition, Plk1 has several functions in mitotic progression. In this study, the authors investigated t he effect of Plk1 depletion on cell cycle progression and proliferation in A549 cells, a lung cancer cell line.Methods A recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells. Reverse transcription-polymerase chain reaction and Western blot were used to examine Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine (BrdU) labelling. Cell cycle and apoptosis were examined by flow cytometry. Expression of α-tubulin was detected by immunofluorescence, and the inhibition rate (IR) by chemotherapeutic agents was determined by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl-tetrazolium bromide assay.Results After transfection into A549 cells, pcDNA3-Plk1 reduced Plk1 mRNA by 46.75% for 24 hours and by 61.84% for 48 hours. Plk1 protein was significantly decreased simultaneously (P<0.05). Abnormal morphological changes of cells and growth inhibition were observed in pcDNA3-Plk1 transfected groups. The BrdU labelling index was 25.59% 48 hours after transfection, which was significantly lower than that of the control groups (P<0.05). Forty-eight hours after transfection, there showed absence of microtubule polymerization and spindle abnormalities in staining for α-tubulin. A549 cells showed a strong G 2/M arrest and apoptosis 72 hours post transfection. IR of vinorelbine in pcDNA3-Plk1 transfected groups was significantly higher than that of the other groups (P<0.05, respectively).Conclusions Plk1 depletion interferes with spindle formation, induces cell cycle arrest and apoptosis, and consequently inhibits cell proliferation in A549 cells. Moreover, it sensitizes lung cancer cells to chemotherapy.
基金partly supported by the Deutsche Forschungsgemeinschaft(DFG INST 268/281-1 FUGG and BE 4572/3-1,Germany)
文摘Polo-like kinase(PLK1) has been identified as a potential target for cancer treatment.Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harbors a regulatory domain, the Polo box domain(PBD), which has a key regulatory function for kinase activity and substrate recognition. We report on 3-bromomethylbenzofuran-2-carboxylic acid ethyl ester(designated: MCC1019) as selective PLK1 inhibitor targeting PLK1 PBD. Cytotoxicity and fluorescence polarization-based screening were applied to a library of 1162 drug-like compounds to identify potential inhibitors of PLK1 PBD. The activity of compound MC1019 against the PLK1 PBD was confirmed using fluorescence polarization and microscale thermophoresis.This compound exerted specificity towards PLK1 over PLK2 and PLK3. MCC1019 showed cytotoxic activity in a panel of different cancer cell lines. Mechanistic investigations in A549 lung adenocarcinoma cells revealed that MCC1019 induced cell growth inhibition through inactivation of AKT signaling pathway, it also induced prolonged mitotic arrest—a phenomenon known as mitotic catastrophe, which is followed by immediate cell death via apoptosis and necroptosis. MCC1019 significantly inhibited tumor growth in vivo in a murine lung cancer model without affecting body weight or vital organ size, and reduced the growth of metastatic lesions in the lung. We propose MCC1019 as promising anti-cancer drug candidate.
文摘AIM: To investigate the effects of polo-like kinase-1 (PLK1) antisense phosphorothioate oligodeoxynucleotide (ASODN) on apoptosis and cell cycle of human colon cancer cell line 5W480.METHODS: After SW480 colon cancer cells were transfected with PLK1 ASODN, Northern and Western blot analyses were used to examine PLK1 gene expression in cancer cells. We studied apoptosis using terminal uridine deoxynucleotidyl nick end labeling. Apoptosis and cell cycle of SW480 cells were examined by fluorescence-activated cell sorter scan.RESULTS: The levels of PLK1 mRNA and protein were greatly inhibited by PLK1 ASODN in SW480 cancer cells transfected with PLK1 ASODN. Apoptosis index (AI) induced PLK1 ASODN in a time- and dose-dependent manner.Results from FLM showed that sub-2N DNA content of transfected cancer cells was significantly increased and arrested at G2/M compared with control groups.CONCLUSION: PLK1 ASODN can induce apoptosis of human colon cancer cell line SW480.
文摘AIM: To elucidate the role of overexpressed polo-like kinase1 (PLK1) in hepatocellular carcinoma (HCC). METHODS: We prospectively collected clinicopathological, immunohistochemical and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) data from 135 HCC patients undergoing successful hepatectomy. The correlations between PLK1 mRNA expression and clinicopathologic variables were analyzed by Mann-Whitney U test. Prognostic factors were identified by univariate and multivariate analyses. RESULTS: Immunohistochemical results showed over-expression of PLK1 was mainly found in tumor tissues compared with tumor-free tissue. A similar mRNA result was obtained by semi-quantitative RT-PCR. A total of 111 samples were positive for PLK1 mRNA expression. The positive expression was correlated with venous invasion, tumor nodules and Edmondson grade. Furthermore, 1, 3, 5-year survival rates in the positive expression group were significantly lower than the negative control group. Multivariate analysis showed that positive PLK1 expres-sion was an independent risk factor for HCC. CONCLUSION: PLK1 could be a potential biomarker for diagnosis and therapy for HCC.
基金supported by the Fundamental Research Funds for the Central Universities(2013HGCH0015)
文摘Polo-like kinase 1(Plk1),a member of a family of serine/threonine kinases,is an attractive target for the development of anticancer drugs because it is involved in the regulation of cell-cycle progression and cytokinesis.This kinase provides two pockets for developing Plk1 inhibitors:the N-terminal catalytic domain(NCD)and the polo-box domain(PBD).For both of the two pockets,some natural products were identified as Plk1 inhibitors and some synthetic Plk1 inhibitors were developed by mimicking ATP and phosphopeptides,natural products binding to NCD and PBD respectively.This article not only reviews the progression of Plk1 inhibitors binding to these two pockets,but also discusses diversity evolution and jump in the process of drug development using Plk1 inhibitors as examples and how they impact on drug design and pharmacophore modeling.
文摘Polo-like kinase 1(PLK1) plays an important role in many cell-cycle-related events. At G2/Mtransition, PLK1 contributes to the activation of cyclinB/Cdc by phosphorylation of Cdc25C, centrosome functional maturation, bipolar spindle formation. In later stage of mitosis, PLK1 is involved in regulating components of the anaphase-promoting complex (APC) for mitotic exit and in the execution of cytokinesis. Moreover, recent reports have shown that PLK1 is involved in both G2 and mitotic DNA damage checkpoints. When G2/M DNA damage occurs, PLK1 activity is suppressed and cell cycle arrests to repair the damaged DNA. So far, the deregulated expression of PLK1 has been detected in many types of human tumors and PLK1 is considered as a novel prognostic marker for several tumors.
基金supported by Research Start-up Funding of Shenzhen Traditional Chinese Medicine Hospital,No.2021-07(to FB)Sanming Project of Medicine in Shenzhen,No.SZZYSM 202111011(to XDQ and FB)+1 种基金Key Discipline Established by Zhejiang Province,Jiaxing City Jointly-Pain Medicine,No.2019-ss-ttyx(to LSX)Jiaxing Key Laboratory of Neurology and Pain Medicine,No.[2014]81(to LSX)。
文摘Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.
基金Supported by the Key Programs of the Educational Commission of Anhui Province,No.2023AH053313the Research Project of Higher Education in Anhui Province in 2022,No.2022AH051192.
文摘BACKGROUND The role of Tousled-like kinase 1(TLK1)in in gastric cancer(GC)remains unclear.AIM To investigate the expression,biological function,and underlying mechanisms of TLK1 in GC.METHODS We measured TLK1 protein expression levels and localized TLK1 in GC cells and tissues by western blot and immunofluorescence,respectively.We transfected various GC cells with lentiviruses to create TLK1 overexpression and knockdown lines and established the functional roles of TLK1 through in vitro colony formation,5-ethynyl-2`-deoxyuridine,and Transwell assays as well as flow cytometry.We applied bioinformatics to elucidate the signaling pathways associated with TLK1.We performed in vivo validation of TLK1 functions by inducing subcutaneous xenograft tumors in nude mice.RESULTS TLK1 was significantly upregulated in GC cells and tissues compared to their normal counterparts and was localized mainly to the nucleus.TLK1 knockdown significantly decreased colony formation,proliferation,invasion,and migration but increased apoptosis in GC cells.TLK1 overexpression had the opposite effects.Bioinformatics revealed,and subsequent experiments verified,that the tumor growth factor-beta signaling pathway was implicated in TLK1-mediated GC progression.The in vivo assays confirmed that TLK1 promotes tumorigenesis in GC.CONCLUSION The findings of the present study indicated that TLK1 plays a crucial role in GC progression and is,therefore,promising as a therapeutic target against this disease.