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
Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c...Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c-myc in lung adenocarcinoma cells. Methods: The effect of compound 6F and A on activities of cytosolic and membrane TPK was measured by scintillation counting; the effect of compound A on expression of oncogene c-myc was determined by flow cytometry indirect fluorimetry. Results: compound 6F and A could inhibit the activities of TOPO I, and they strongly inhibited the TOPO II in 0.01 mg/L and 10.0 mg/L respectively. Compound A slightly inhibited the activities of membrane TPK, but not the cytosolic one. Compound A could inhibit the expression of oncogene c-myc. Conclusion: Topoisomerases are target of compound 6F and A. Compound A could slightly inhibit the activities of TPK, and showed an inhibitory effect on the expression of oncogene c-myc.展开更多
Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoprotei...Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRβ fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.展开更多
AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARP...AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for α-smooth muscle actin (α-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. α-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, α-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.展开更多
AIM:To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration. METHODS:Gastric lesions were induced in rats using restraint cold stress.To investigate the e...AIM:To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration. METHODS:Gastric lesions were induced in rats using restraint cold stress.To investigate the effect of oxidative and nitrosative cell stress on tyrosine phosphorylation during wound repair,total activity of protein tyrosine kinase(PTK),protein tyrosine phosphatase (PTP),antioxidant enzymes,nitric oxide synthase (NOS), 2',5'-oligoadenylate synthetase,hydroxyl radical and zinc levels were assayed in parallel. RESULTS:Ulcer provocation induced an immediate decrease in tyrosine kinase(40% in plasma membranes and 56% in cytosol,(P<0.05) and phosphatase activity (threefold in plasma membranes and 3.3-fold in cytosol),followed by 2.3-2.4-fold decrease (P<0.05) in protein phosphotyrosine content in the gastric mucosa. Ulceration induced no immediate change in superoxide dismutase (SOD) activity,30% increase (P<0.05) in catalase activity,2.3-fold inhibition (P<0.05) of glutathione peroxidase,3.3-fold increase (P<0.05) in hydroxyl radical content,and 2.3-fold decrease (P<0.05) in zinc level in gastric mucosa.NOS activity was three times higher in gastric mucosa cells after cold stress. Following ulceration,PTK activity increased in plasma membranes and reached a maximum on day 4 after stress (twofold increase,P<0.05),but remained inhibited(1.6-3-fold decrease on days 3,4 and 5,P<0.05) in the cytosol.Tyrosine phosphatases remained inhibited both in membranes and cytosol(1.5-2.4-fold,P< 0.05).NOS activity remained increased on days 1,2 and 3(3.8-,2.6-,2.2-fold,respectively,P<0.05).Activity of SOD increased 1.6 times(P<0.05)days 4 and 5 after stress.Catalase activity normalized after day 2. Glutathione peroxidase activity and zinc level decreased (3.3-and 2-fold,respectively,P<0.05)on the last day. Activity of 2',5'-oligoadenylate synthethase increased 2.8-fold (P<0.05) at the beginning,and 1.6-2.3-fold (P<0.05) during ulcer recuperation,and normalized on day 5,consistent with slowing of inflammation processes. CONCLUSION:These studies show diverse changes in total tyrosine kinase activity in gastric mucosa during the recovery process.Oxidative and nitrosative stress during lesion formation might lead to the observed reduction in tyrosine phosphorylation during ulceration.展开更多
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.
基金the National Natural Science Foundation of China (No. 39870900) and the key project grant from Guangdong Province Science and Te
文摘Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c-myc in lung adenocarcinoma cells. Methods: The effect of compound 6F and A on activities of cytosolic and membrane TPK was measured by scintillation counting; the effect of compound A on expression of oncogene c-myc was determined by flow cytometry indirect fluorimetry. Results: compound 6F and A could inhibit the activities of TOPO I, and they strongly inhibited the TOPO II in 0.01 mg/L and 10.0 mg/L respectively. Compound A slightly inhibited the activities of membrane TPK, but not the cytosolic one. Compound A could inhibit the expression of oncogene c-myc. Conclusion: Topoisomerases are target of compound 6F and A. Compound A could slightly inhibit the activities of TPK, and showed an inhibitory effect on the expression of oncogene c-myc.
基金This work was partially supported by a grant from World Health Organization Fellowship (XS) (WPRO AWARD No. 0008/99).
文摘Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRβ fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.
基金Supported by Shandong Provincial Natural Science Foundation,China(No.ZR2012HQ004)the Research Fund for Fundamental Research Project of Qingdao(No.13-1-4-180-jch)+1 种基金the Scientific Research Fund of Huangdao District of Qingdao City(No.2014-1-74)the Young People Scientific Research Fund of Affiliated Hospital,Qingdao University(No.QDFY134)
文摘AIMTo evaluate whether protein tyrosine phosphatase 1B (PTP1B) contributed to initiate human retinal pigment epithelium cells (A)-19 migration and investigate the signaling pathways involved in this process.METHODSARPE-19 cells were cultured and treated with the siRNA-PTP1B. Expression of PTP1B was confirmed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). AG1478 [a selective inhibitor of epidermal growth factor receptor (EGFR)] and PD98059 (a specific inhibitor of the activation of mitogen-activated protein kinase) were used to help to determine the PTP1B signaling mechanism. Western blot analysis verified expression of EGFR and extracellular signal-regulated kinase (ERK) in ARPE-19 cells. The effect of siRNA-PTP1B on cell differentiation was confirmed by immunostaining for α-smooth muscle actin (α-SMA) and qRT-PCR. Cell migration ability was analyzed by transwell chamber assay.RESULTSThe mRNA levels of PTP1B were reduced by siRNA-PTP1B as determined by qRT-PCR assay. SiRNA-PTP1B activated EGFR and ERK phosphorylation. α-SMA staining and qRT-PCR assay demonstrated that siRNA-PTP1B induced retinal pigment epithelium (RPE) cells to differentiate toward better contractility and motility. Transwell chamber assay proved that PTP1B inhibition improved migration activity of RPE cells. Treatment with AG1478 and PD98059 abolished siRNA-PTP1B-induced activation of EGFR and ERK, α-SMA expression and cell migration.CONCLUSIONPTP1B inhibition promoted myofibroblast differentiation and migration of ARPE-19 cells, and EGFR/ERK signaling pathway played important role in migration process.
基金Supported by Travel grants from The Physiological Society(UKand Eire),Federation of European Physiological SocietiesThe Cousins Center for Psychoneuroimmunology at the UCLA Neuropsychiatric Institute travel assistant award
文摘AIM:To investigate the role of protein tyrosine phosphorylation in gastric wound formation and repair following ulceration. METHODS:Gastric lesions were induced in rats using restraint cold stress.To investigate the effect of oxidative and nitrosative cell stress on tyrosine phosphorylation during wound repair,total activity of protein tyrosine kinase(PTK),protein tyrosine phosphatase (PTP),antioxidant enzymes,nitric oxide synthase (NOS), 2',5'-oligoadenylate synthetase,hydroxyl radical and zinc levels were assayed in parallel. RESULTS:Ulcer provocation induced an immediate decrease in tyrosine kinase(40% in plasma membranes and 56% in cytosol,(P<0.05) and phosphatase activity (threefold in plasma membranes and 3.3-fold in cytosol),followed by 2.3-2.4-fold decrease (P<0.05) in protein phosphotyrosine content in the gastric mucosa. Ulceration induced no immediate change in superoxide dismutase (SOD) activity,30% increase (P<0.05) in catalase activity,2.3-fold inhibition (P<0.05) of glutathione peroxidase,3.3-fold increase (P<0.05) in hydroxyl radical content,and 2.3-fold decrease (P<0.05) in zinc level in gastric mucosa.NOS activity was three times higher in gastric mucosa cells after cold stress. Following ulceration,PTK activity increased in plasma membranes and reached a maximum on day 4 after stress (twofold increase,P<0.05),but remained inhibited(1.6-3-fold decrease on days 3,4 and 5,P<0.05) in the cytosol.Tyrosine phosphatases remained inhibited both in membranes and cytosol(1.5-2.4-fold,P< 0.05).NOS activity remained increased on days 1,2 and 3(3.8-,2.6-,2.2-fold,respectively,P<0.05).Activity of SOD increased 1.6 times(P<0.05)days 4 and 5 after stress.Catalase activity normalized after day 2. Glutathione peroxidase activity and zinc level decreased (3.3-and 2-fold,respectively,P<0.05)on the last day. Activity of 2',5'-oligoadenylate synthethase increased 2.8-fold (P<0.05) at the beginning,and 1.6-2.3-fold (P<0.05) during ulcer recuperation,and normalized on day 5,consistent with slowing of inflammation processes. CONCLUSION:These studies show diverse changes in total tyrosine kinase activity in gastric mucosa during the recovery process.Oxidative and nitrosative stress during lesion formation might lead to the observed reduction in tyrosine phosphorylation during ulceration.
