TMED2 Induces Cisplatin Resistance in Breast Cancer via Targeting the KEAP1-Nrf2 Pathway

Objective Cisplatin is the first-line treatment for breast cancer,but it faces challenges of drug resistance.This study investigated new molecular mechanisms underlying cisplatin resistance in breast cancer.Methods We analyzed sequencing data from the TCGA database to identify potential associations between transmembrane emp24 protein transport domain containing 2(TMED2)and breast cancer.Western blotting,real-time PCR,CCK-8,and TUNEL assays were used to measure the effects and molecular mechanism of TMED2 on cisplatin resistance in MCF-7 and MDA-MB-231 cell lines.Results TMED2 was overexpressed in breast cancer and associated with poor prognosis.TMED2 increased cisplatin resistance in breast cancer cells in vitro via promoting ubiquitination of Kelch-like ECH-associated protein 1(KEAP1),relieving inhibition of KEAP1 on nuclear factor erythroid 2-related factor 2(Nrf2),and increasing expression of downstream drug resistance related genes,such as heme oxygenase 1(HO-1)and NAD(P)H quinone oxidoreductase 1(NQO1).Conclusion We identified a new molecular mechanism by which TMED2 affects cisplatin resistance in breast cancer.Our results provide theoretical guidance for future clinical applications.

ARID1A Inactivation Increases Expression of circ0008399 and Promotes Cisplatin Resistance in Bladder Cancer

Objective Cisplatin(CDDP)-based chemotherapy is a first-line,drug regimen for muscle-invasive bladder cancer(BC)and metastatic bladder cancer.Clinically,resistance to CDDP restricts the clinical benefit of some bladder cancer patients.AT-rich interaction domain 1A(ARID1A)gene mutation occurs frequently in bladder cancer;however,the role of CDDP sensitivity in BC has not been studied.Methods We established ARID1A knockout BC cell lines using CRISPR/Cas9 technology.IC50 determination,flow cytometry analysis of apoptosis,and tumor xenograft assays were performed to verify changes in the CDDP sensitivity of BC cells losing ARID1A.qRT-PCR,Western blotting,RNA interference,bioinformatic analysis,and ChIP-qPCR analysis were performed to further explore the potential mechanism of ARID1A inactivation in CDDP sensitivity in BC.Results It was found that ARID1A inactivation was associated with CDDP resistance in BC cells.Mechanically,loss of ARID1A promoted the expression of eukaryotic translation initiation factor 4A3(EIF4A3)through epigenetic regulation.Increased expression of EIF4A3 promoted the expression of hsa_circ_0008399(circ0008399),a novel circular RNA(circRNA)identified in our previous study,which,to some extent,showed that ARID1A deletion caused CDDP resistance through the inhibitory effect of circ0008399 on the apoptosis of BC cells.Importantly,EIF4A3-IN-2 specifically inhibited the activity of EIF4A3 to reduce circ0008399 production and restored the sensitivity of ARID1A inactivated BC cells to CDDP.Conclusion Our research deepens the understanding of the mechanisms of CDDP resistance in BC and elucidates a potential strategy to improve the efficacy of CDDP in BC patients with ARID1A deletion through combination therapy targeting EIF4A3.

Deciphering key genes involved in cisplatin resistance in kidney renal clear cell carcinoma through a combined in silico and in vitro approach

The low survival rate of Kidney renal clear cell carcinoma(KIRC)patients is largely attributed to cisplatin resistance.Rather than focusing solely on individual proteins,exploring protein-protein interactions could offer greater insight into drug resistance.To this end,a series of in silico and in vitro experiments were conducted to identify hub genes in the intricate network of cisplatin resistance-related genes in KIRC chemotherapy.The genes involved in cisplatin resistance across KIRC were retrieved from the National Center for Biotechnology Information(NCBI)database using search terms as“Kidney renal clear cell carcinoma”and“Cisplatin resistance”.The genes retrieved were analyzed for hub gene identification using the STRING database and Cytoscape tool.Expression and promoter methylation profiling of the hub genes was done using UALCAN,GEPIA,OncoDB,and HPA databases.Mutational,survival,functional enrichment,immune cell infiltration,and drug prediction analyses of the hub genes were performed using the cBioPortal,GEPIA,GSEA,TIMER,and DrugBank databases.Lastly,expression and methylation levels of the hub genes were validated on two cisplatin-resistant RCC cell lines(786-O and A-498)and a normal renal tubular epithelial cell line(HK-2)using two high throughput techniques,including targeted bisulfite sequencing(bisulfite-seq)and RT-qPCR.A total of 124 genes were identified as being associated with cisplatin resistance in KIRC.Out of these genes,MCL1,IGF1R,CCND1,and PTEN were identified as hub genes and were found to have significant(p<0.05)variations in their mRNA and protein expressions and effects on the overall survival(OS)of the KIRC patients.Moreover,an aberrant promoter methylation pattern was found to be associated with the dysregulation of the hub genes.In addition to this,hub genes were also linked with different cisplatin resistance-causing pathways.Thus,hub genes can be targeted with Alvocidib,Estradiol,Tretinoin,Capsaicin,Dronabinol,Metribolone,Calcitriol,Acetaminophen,Acitretin,Cyclosporine,Azacitidine,Genistein,and Resveratrol drugs.As the pathogenesis of KIRC is complex,targeting hub genes and associated pathways involved in cisplatin resistance could bring a milestone change in the drug discovery and management of drug resistance,which might uplift overall survival among KIRC patients.

mir-3168 targeted inhibition of TP53 promotes malignant transformation and cisplatin resistance of AGS and AGS/DDP gastric cancer cells

Objective:To investigate the effect of mir-3168 on the malignant transformation and cisplatin resistance of AGS and AGS/DDP gastric cancer cells,and to verify its target gene.Methods:The expression of mir-3168 in AGS and AGS/DDP gastric cancer cells was detected by qPCR,and mir-3168 mimic,inhibitor and negative control were synthesized.They were transfected into AGS and AGS/DDP gastric cancer cells,respectively.The expression of mir-3168 and TP53 mRNA was detected by qPCR.Cell viability was detected by CCK8 under gradient cisplatin treatment and non treatment,apoptosis was detected by flow cytometry,cell invasion was detected by Transwell,and TP53 protein expression was detected by western blot,The database predicted the binding sites of mir-3168 and TP53.According to the binding sites,the double luciferase experiment was used to verify the binding of mir-3168 and TP53.Results:Compared with cisplatin sensitive gastric cancer cell AGS,mir-3168 was significantly overexpressed in cisplatin resistant gastric cancer cell AGS/DDP;mir-3168 mimic promotes cisplatin resistance,proliferation and invasion of AGS and AGS/DDP gastric cancer cells,and inhibits apoptosis of AGS and AGS/DDP gastric cancer cells;mir-3168 inhibitor inhibits cisplatin resistance,proliferation and invasion of AGS and AGS/DDP gastric cancer cells,and promotes apoptosis of AGS and AGS/DDP gastric cancer cells;mir-3168 mimic inhibits the expression of TP53 mRNA and protein,and mir-3168 inhibitor promotes the expression of TP53 mRNA and protein;Targetscan database predicted that there was a binding point between mir-3168 and TP53,and the double luciferase experiment suggested that mir-3168 was bound to TP53 through the predicted binding site.Conclusion:mir-3168 may promote the malignant transformation of AGS and AGS/DDP gastric cancer cells and cisplatin resistance by targeting TP53.

Exosomal microRNA-588 from M2 polarized macrophages contributes to cisplatin resistance of gastric cancer cells

BACKGROUND Gastric cancer is a prevalent malignant cancer with a high incidence and significantly affects the health of modern people globally.Cisplatin(DDP)is one of the most common and effective chemotherapies for patients with gastric cancer,but DDP resistance remains a severe clinical challenge.AIM To explore the function of M2 polarized macrophages-derived exosomal microRNA(miR)-588 in the modulation of DDP resistance of gastric cancer cells.METHODS M2 polarized macrophages were isolated and identified by specific markers using flow cytometry analysis.The exosomes from M2 macrophages were identified by transmission electron microscopy and related markers.The uptake of the PKH67-labelled M2 macrophages-derived exosomes was detected in SGC7901 cells.The function and mechanism of exosomal miR-588 from M2 macrophages in the modulation of DDP resistance of gastric cancer cells was analyzed by CCK-8 assay,apoptosis analysis,colony formation assay,Western blot analysis,qPCR analysis,and luciferase reporter assay in SGC7901 and SGC7901/DDP cells,and by tumorigenicity analysis in nude mice.RESULTS M2 polarized macrophages were isolated from mouse bone marrow stimulated with interleukin(IL)-13 and IL-4.Co-cultivation of gastric cancer cells with M2 polarized macrophages promoted DDP resistance.M2 polarized macrophagesderived exosomes could transfer in gastric cancer cells to enhance DDP resistance.Exosomal miR-588 from M2 macrophages contributed to DDP resistance of gastric cancer cells.miR-588 promoted DDP-resistant gastric cancer cell growth in vivo.miR-588 was able to target cylindromatosis(CYLD)in gastric cancer cells.The depletion of CYLD reversed miR-588 inhibition-regulated cell proliferation and apoptosis of gastric cancer cells exposed to DDP.CONCLUSION In conclusion,we uncovered that exosomal miR-588 from M2 macrophages contributes to DDP resistance of gastric cancer cells by partly targeting CYLD.miR-588 may be applied as a potential therapeutic target for the treatment of gastric cancer.

Upregulation of miR-34c after silencing E2F transcription factor 1 inhibits paclitaxel combined with cisplatin resistance in gastric cancer cells

BACKGROUND MicroRNA 34c(miR-34c)has been reported to be associated with malignant types of cancer,however,it remains unknown whether miR-34c is involved in chemoresistance in gastric cancer(GC).AIM To investigate the effect of miR-34c and its upstream transcription factor E2F1 on paclitaxel combined with cisplatin resistance in GC cells.METHODS Paired GC tissues and adjacent normal tissues were randomly sampled from 74 GC patients.miR-34c and E2F1 were detected by real-time quantitative PCR(qPCR)and Western blot.In addition,the drug resistance of GC cells to paclitaxel and cisplatin was induced by concentration gradient increasing methods,and changes in miR-34c and E2F1 during this process were measured.Furthermore,E2F1 and miR-34c overexpression or underexpression vectors were constructed and transfected into drug-resistant GC cells.MTT was employed to test the sensitivity of cells to paclitaxel combined with cisplatin,qPCR was adopted to detect the expression of miR-34c,Western blot was applied to detect the expression levels of E2F1,drug resistance-related proteins and apoptosis-related proteins,and flow cytometry was used for the determination of cell apoptosis and cell cycle status.RESULTS E2F1 was overexpressed while miR-34c was underexpressed in GC.After inducing GC cells to be resistant to paclitaxel and cisplatin,E2F1 expression increased while miR-34c expression decreased.Both silencing E2F1 and overexpressing miR-34c could increase the sensitivity of drug-resistant GC cells to paclitaxel combined with cisplatin,promote cell apoptosis and inhibit cell proliferation.Among which,silencing E2F1 could reduce the expression of drug resistance-related proteins and apoptosis-related proteins,while over-expression of miR-34c could upregulate the expression of apoptosis-related proteins without affecting the expression of MDR-1,MRP and other drug resistance-related proteins.Rescue experiments demonstrated that inhibiting miR-34c could significantly weaken the sensitization of drug resistant cells,and Si E2F1 to paclitaxel combined with cisplatin.CONCLUSION E2F1 inhibits miR-34c to promote the proliferation of GC cells and enhance the resistance to paclitaxel combined with cisplatin,and silencing E2F1 is conducive to improving the efficacy of paclitaxel combined with cisplatin in GC cells.

MiR-106a Targets Mcl-1 to Suppress Cisplatin Resistance of Ovarian Cancer A2780 Cells

Summary： Resistance to chemotherapy is a major obstacle for the effective treatment of advanced ovarian cancer. The mechanism of chemoresistance is still poorly understood. Recently, more and more evidence showed microRNAs （miRNAs） modulated many key molecules and pathways involved in chemotherapy, microRNA-106a （miR-106a） has been implicated in many cancers, but its role in ovarian cancer and drug resistance still remains unexplored. This study was to investigate whether miR-106a mediated resistance of the ovarian cancer cell line A2780 to the chemotherapeutic agent cisplatin （DDP）. The different levels of miR-106a in A2780 cells and their resistant variant A2780/DDP cells were identified by using real-time PCR. MTT assay and flow cytometry were used to analyze the effect of miR-106a on cisplatin resistance of these paired cells. Real-time PCR, Western blotting and luciferase reporter assay were applied to explore whether Mcl-1 was a target of miR-106a. As compared to A2780 cells, the expression of miR-106a was down-regulated in the cisplatin resistant cell line A2780/DDP. Moreover, knockdown of miR-106a dramatically decreased antiproliferative effects and apoptosis induced by cisplatin in A2780 cells, while overexpression of miR-106a significantly increased antiproliferative effects and apoptosis induced by cisplatin in A2780/DDP cells. Furthermore, miR-106a inhibited cell survival and cisplatin resistance through downregulating the expression of Mcl-1. Mcl-1 was a di- rect target of miR-106a. These results suggest that miR-106a may provide a novel mechanism for un- derstanding cisplatin resistance in ovarian cancer by modulating Mcl-1.

miR-3622b-5p regulates cisplatin resistance of human gastric cancer cell line by targeting BIRC5

Many evidences showed that drug resistance of gastric cancer cells could be regulated by the abnormal expression of microRNAs(miRNAs),a post-transcriptional regulator of gene expression.Thus,we investigated the role of miR-3622b-5p in the development of cisplatin resistance in human gastric cancer cell lines.A set of biochemical assays were used to elucidate the mechanism by which miR-3622b-5p regulates drug resistance in cancer cells.The expression of miR-3622b-5p was measured by quantitative real-time PCR and showed that MiR-3622b-5p was significantly downregulated in the plasma of patients with acquired drug resistance to platinumbased chemotherapy for gastric cancer.MiR-3622b-5p was also found significantly downregulated in cisplatinresistant gastric cancer cell line SGC7901/cisplatin(DDP),compared with the parental SGC7901 cells.An in vitro drug sensitivity assay showed that overexpression of miR-3622b-5p sensitized SGC7901/DDP cells to cisplatin.The luciferase activity of reporters constructed by BIRC53′-untranslated regions in SGC7901/DDP cells suggested that BIRC5 was target gene of miR-3622b-5p.Ecpotic miR-3622b-5p expression in SGC7901/DDP cells significantly repressed the expression of the BIRC5 and sensitized the cells to DDP-induced apoptosis.By contrast,treatment with miR-3622b-5p inhibitor increased the protein expression of BIRC5 and led to a lower proportion of apoptotic cells in the SGC7901 cells.In conclusion,our findings suggest that miR-3622b-5p regulates cisplatin resistance of human gastric cancer cells at least in part by repressing the expression of BIRC5.Altering miR-3622b-5p expression may be a potential therapeutic strategy for the treatment of chemoresistance in GC in the future.

Formulated nano-liposomes for reversal of cisplatin resistance in NSCLC with nucleus-targeting peptide

Cell membrane-engineered nano-delivery systems have evolved as a promising strategy to enhance drug bioavailability,offering an alternative for reversing drug resistance in cancer therapy.Herein,a formulated nano-liposome that fabricated by hybridizing cisplatin-resistant A549 cell line(A549/cis)cancer cell membrane and phospholipids for co-delivery of cisplatin and nuclear protein zeste homolog 2(EZH2)-targeting peptide EIP103,referred to as cLCE,was developed.In vitro results indicated that the formulated nano-liposome can efficiently inhibit A549/cis cancer cell invasion and metastasis through the down-regulation of Ncadherin and vimentin proteins.Mechanistic studies demonstrated that the reduction of nerve growth factor receptor(NGFR)levels and the increase of peroxisome proliferator-activated receptorγ(PPARγ)levels achieved by EIP103 may contribute to the reversal of cisplatin resistance.In vivo results demonstrated that the encapsulation of both cisplatin and EIP103 within cLCE leads to increased intratumoral accumulation and prolonged survival in A549/cis cancer-bearing mice as compared to the individual drugs alone.This can be attributed to the enhanced tumor homing capability of cLCE achieved through the presence of inherited membrane proteins derived from A549/cis cells.Taken together,this study may provide a highly promising therapeutic strategy to improve clinical treatments for cisplatin-resistance non-small-cell lung cancer(NSCLC)as well as other malignant cancers.

MiR-503 regulates cisplatin resistance of human gastric cancer cell lines by targeting IGF1R and BCL2

Background Studies have shown that the drug resistance of gastric cancer cells can be modulated by abnormal expression of microRNAs （miRNAs）.We investigated the role of miR-503 in the development of cisplatin resistance in human gastric cancer cell lines.Methods MiR-503 expression was measured by quantitative real-time PCR.MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） and clonogenic assays were used to examine changes in cell viability and the drug resistance phenotype of cancer cells associated with upregulation or downregulation of the miRNA.A dual-luciferase activity assay was used to verify target genes of miR-503.Immunohistochemistry,Western blotting analysis,and a flow cytometric apoptosis assay were used to elucidate the mechanism by which miR-503 modulates drug resistance in cancer cells.Results MiR-503 was significantly downregulated in gastric cancer tissues and several gastric cancer cell lines.Additionally,downregulation of miR-503 in the cisplatin （DDP）-resistant gastric cancer cell line SGC7901/DDP was concurrent with the upregulation of insulin-like growth factor-1 receptor （IGF1R） and B-cell lymphoma 2 （BCL2） expression compared with the parental SGC7901 cell line.An in vitro drug sensitivity assay showed that overexpression of miR-503 sensitized SGC7901/DDP cells to cisplatin.The luciferase activity of reporters driven by IGF1R and BCL2 3＇-untranslated regions in SGC7901/DDP cells suggested that IGF1R and BCL2 were both direct target genes of miR-503.Enforced miR-503 expression in SGC7901/DDP cells reduced expression of the target proteins,inhibited proliferation,and sensitized the cells to DDP-induced apoptosis.Conclusion Our findings suggest that hsa-miR-503 modulates cisplatin resistance of human gastric cancer cells at least in part by targeting IGF1R and BCL2.

miR-125b Confers Resistance of Ovarian Cancer Cells to Cisplatin by Targeting Pro-apoptotic Bcl-2 Antagonist Killer 1

Chemotherapy is the preferred therapeutic approach for advanced ovarian cancer,but a successful long-term treatment is prevented by the development of drug resistance.Recent works have underlined the involvement of non-coding RNAs,microRNAs（miRNAs） in cancer development,with several conjectures regarding their possible involvement in the evolution of drug resistance.This study is to investigate the promoting effects and mechanism of miR-125b involved in the development of chemoresistance in ovarian cancer.The different expression of miR-125b in cisplatin-sensitive ovarian cancer cell line（OV2008） and its resistant variant（C13＊） was identified by real-time PCR.An in vitro cytotoxicity assay and apoptosis assay using CCK-8 assay and flow cytometry,were carried out to detect the effect of miR-125b and Bak1 on cisplatin resistance of cells.Real-time PCR,Western blotting and luciferase reporter assay were used to detect whether Bak1 is a target of miR-125b.As compared with OV2008 cells,the expression levels of miR-125b in C13＊ cells were increased.It was found that the up-regulation of microRNA-125b caused a marked inhibition of cisplatin-induced cytotoxicity and apoptosis and a subsequent increase in the resistance to cisplatin in OV2008 and C13＊ cells.Moreover,Bak1 was a direct target of miR-125b,and down-regulation of Bak1 suppressed cisplatin-induced apoptosis and led to an increased resistance to cisplatin.Our study indicates that miR-125b has a significantly promoting effect on chemoresistance of C13＊ cells and up-regulation of miR-125b expression contributes to cisplatin resistance through suppression of Bak1 expression.This finding has important implications in the development of targeted therapeutics for overcoming cisplatin resistance in ovarian cancer.

Ethaselen: a novel organoselenium anticancer agent targeting thioredoxin reductase 1 reverses cisplatin resistance in drug-resistant K562 cells by inducing apoptosis

It has been reported that Ethaselen shows inhibitory effects on thioredoxin reductase（TrxR） activity and human tumor cell growth. In order to find an efficient way to reverse cisplatin resistance, we investigated the reversal effects of Ethaselen on cisplatin resistance in K562/cisplatin（CDDP） cells that were established by pulse-inducing human erythrocyte leukemic cell line K562, which are fivefold more resistant to cisplatin compared to K562 cells. The morphology and growth showed that the adhesion of K562/CDDP further decreased while the cell volume increased. The proliferation of K562/CDDP is strengthened. The antitumor activities in vitro were assessed by MTT（3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay and combination index（CI）, showing the significant synergic effects of cisplatin and Ethaselen. Focusing on apoptosis, a series of comparisons was made between K562 and K562/CDDP. Cisplatin induced higher reactive oxygen species（ROS） generation in K562 and subsequently induced the formation of mitochondrial permeability transition pores（PTPs）. In addition, cisplatin increased the ratio of Bax to Bcl-2 in K562, which can influence the mitochondrial membrane permeability. PTP formation and mitochondrial membrane permeabilization eventually resulted in the release of cytochrome c and activation of the Caspase pathway. However, these effects were not clearly seen in K562/CDDP, which may be the reason for the acquired CDDP resistance. However, Ethaselen can induce a high level of ROS in K562/CDDP by TrxR activity inhibition and increased ratio of Bax to Bcl-2 in K562/CDDP by nuclear factor κB（NF-κB） suppression, which subsequently induces the release of cytochrome c in K562/CDDP. This response is partly responsible for the reversal of the cisplatin resistance in K562/CDDP cells.

Elevated extracellular calcium ions accelerate the proliferation and migration of HepG2 cells and decrease cisplatin sensitivity

Hepatoblastoma is the most frequent liver malignancy in children.HepG2 has been discovered as a hepatoblastoma-derived cell line and tends to form clumps in culture.Intriguingly,we observed that the addition of calcium ions reduced cell clumping and disassociated HepG2 cells.The calcium signal is in connection with a series of processes critical in the tumorigenesis.Here,we demonstrated that extracellular calcium ions induced morphological changes and enhanced the epithelial-mesenchymal transition in HepG2 cells.Mechanistically,calcium ions promoted HepG2 proliferation and migration by up-regulating the phosphorylation levels of focal adhesion kinase(FAK),protein kinase B,and p38 mitogen-activated protein kinase.The inhibitor of FAK or Ca2+/calmodulin-dependent kinaseⅡ(CaMKⅡ)reversed the Ca2+-induced effects on HepG2 cells,including cell proliferation and migration,epithelial-mesenchymal transition protein expression levels,and phosphorylation levels of FAK and protein kinase B.Moreover,calcium ions decreased HepG2 cells'sensitivity to cisplatin.Furthermore,we found that the expression levels of FAK and CaMKⅡwere increased in hepatoblastoma.The group with high expression levels of FAK and CaMKⅡexhibited significantly lower ImmunoScore as well as CD8+T and NK cells.The expression of CaMKⅡwas positively correlated with that of PDCD1 and LAG3.Correspondingly,the expression of FAK was negatively correlated with that of TNFSF9,TNFRSF4,and TNFRSF18.Collectively,extracellular calcium accelerates HepG2 cell proliferation and migration via FAK and CaMKⅡand enhances cisplatin resistance.FAK and CaMKⅡshape immune cell infiltration and responses in tumor microenvironments,thereby serving as potential targets for hepatoblastoma.

A nanocomposite competent to overcome cascade drug resistance in ovarian cancer via mitochondria dysfunction and NO gas synergistic therapy

Ovarian cancer(OC)is one of the most common and recurring malignancies in gynecology.Patients with relapsed OC always develop"cascade drug resistance"(CDR)under repeated chemotherapy,leading to subsequent failure of chemotherapy.To overcome this challenge,amphiphiles(P1)carrying a nitric oxide(NO)donor(Isosorbide 5-mononitrate,ISMN)and high-density disulfide are synthesized for encapsulatingmitochondria-targeted tetravalent platinum prodrug(TPt)to construct a nanocomposite(INP@TPt).Mechanism studies indicated that INP@TPt significantly inhibited drug-resistant cells by increasing cellular uptake and mitochondrial accumulation of platinum,depleting glutathione,and preventing apoptosis escape through generating highly toxic peroxynitrite anion(ONOO−).To better replicate the microenvironmental and histological characteristics of the drug resistant primary tumor,an OC patient-derived tumor xenograft(PDXOC)model in BALB/c nude mice was established.INP@TPt showed the best therapeutic effects in the PDXOC model.The corresponding tumor tissues contained high ONOO−levels,which were attributed to the simultaneous release of O_(2)^(·−)and NO in tumor tissues.Taken together,INP@TPtbased systematic strategy showed considerable potential and satisfactory biocompatibility in overcoming platinum CDR,providing practical applications for ovarian therapy.

THE EFFECT OF IRISQUINONE ON THE GLUTATHIONE SYSTEM AND MRP EXPRESSION OF CISPLATIN-RESISTANTHUMAN LUNG ADENOCARCINOMA CELL LINE (A_(549)^(DDP))

Objective: To investigate the Reversal Effect of Irisquinone (ANKA) on Cisplatin-resistant Human Lung Adenocarcinoma Cell Line (A 549 DDP ) and the change of MRP expression. Methods: MTT assay, flow cytometry, glutathione reductase recycling assay, RT-PCR were used. Results: None or low cytotoxic concentration of ANKA (10, 20, 30 μmol/L) could increase the sensitivity of A 549 DDP cells to CDDP by 8.2, 7.9 and 8.9-fold in a dose independent manner. After A 549 DDP cells was pretreated with 10 μmol/L ANKA for 12 h, CDDP cytotoxicity was increased 9.41-fold. The GSH content of the cells treated by ANKA is reduced significantly (P<0.001). The GSTπ protein expression was reduced by ANKA depended on its doses. ANKA also reduced expression of MRP protein, dependent on its dose and treating time (P<0.001). MRP mRNA expression was reduced only by 30μmol/L ANKA (P<0.05). Conclusion: The reversal effect of ANKA on A 549 DDP cell was relative to intracellular glutathione system.

Dysregulation of mRNA profile in cisplatin-resistant gastric cancer cell line SGC7901

AIM To explore novel therapeutic target of cisplatin resistance in human gastric cancer.METHODS The sensitivity of SGC7901 cells and cisplatin-resistant SGC7901 cells(SGC7901/DDP) for cisplatin were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. High-quality total RNA which isolated from SGC7901/DDP cells and SGC7901 cells were used for mR NA microarray analysis. Results were analyzed bioinformatically to predict their roles in the development of cisplatin resistance and the expression of 13 dysregulated mR NAs we selected were validated by quantitative real-time polymerase chain reaction(qR T-PCR). RESULTS SGC7901/DDP cells highly resistant to cisplatin demonstrated by MTT assay. A total of 1308 m RNAs(578 upregulated and 730 downregulated) were differentially expressed(fold change ≥ 2 and P-value < 0.05) in the SGC7901/DDP cells compared with SGC7901 cells. The expression of mR NAs detected by q RT-PCR were consistent with the microarray results. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway and protein-protein interaction analysis demonstrated that the differentially expressed mR NAs were enriched in PI3K-Akt, Notch, MAPK, ErbB, Jak-STAT, NF-kappa B signaling pathways which may be involved in cisplatin resistance. Several genes such as PDE3 B, VEGFC, IGFBP3, TLR4, HIPK2 and EGF may associated with drug resistance of gastric cancer cells to cisplatin.CONCLUSION Exploration of those altered mR NAs may provide more promising strategy in diagnosis and therapy for gastric cancer with cisplatin resistance.

Curcumin Synergizes with Cisplatin to Inhibit Colon Cancer through Targeting the MicroRNA-137-Glutaminase Axis

Objective:Colorectal cancer(CRC)is one of the most lethal and prevalent malignancies world-wide.Currently,surgery,radiotherapy and chemotherapy are clinically applied as common approaches for CRC patients.Cisplatin is one of the most frequently used chemotherapy drugs for diverse cancers.Although chemotherapeutic strategies have improved the prognosis and survival of cancer patients,development of cisplatin resistance has led to cancer recurrence.Curcumin,isolated from turmeric,has been used as an effective anti-cancer agent.However,the molecular mechanisms for curcumin-mediated cisplatin sensitivity of CRC have not been elucidated.

Identification of functional genes regulating gastric cancer progression using integrated bioinformatics analysis

BACKGROUND Gastric cancer(GC)is one of the most common cancers and has a poor prognosis.Treatment of GC has remained unchanged over the past few years.AIM To investigate the potential therapeutic targets and related regulatory biomarkers of GC.METHODS We obtained the public GC transcriptome sequencing dataset from the Gene Expression Omnibus database.The datasets contained 348 GC tissues and 141 healthy tissues.In total,251 differentially expressed genes(DEGs)were identified,including 187 down-regulated genes and 64 up-regulated genes.The DEGs’enriched functions and pathways include Progesterone-mediated oocyte maturation,cell cycle,and oocyte meiosis,Hepatitis B,and the Hippo signaling pathway.Survival analysis showed that BUB1,MAD2L1,CCNA2,CCNB1,and BIRC5 may be associated with regulation of the cell cycle phase mitotic spindle checkpoint pathway.We selected 26 regulated genes with the aid of the protein-protein interaction network analyzed by Molecular Complex Detection.RESULTS We focused on three critical genes,which were highly expressed in GC,but negatively related to patient survival.Furthermore,we found that knockdown of Yu K et al.Biochemical analysis in GC WJCC https://www.wjgnet.com 5024 July 26,2023 Volume 11 Issue 21 BIRC5,TRIP13 or UBE2C significantly inhibited cell proliferation and induced cell apoptosis.In addition,knockdown of BIRC5,TRIP13 or UBE2C increased cellular sensitivity to cisplatin.CONCLUSION Our study identified significantly upregulated genes in GC with a poor prognosis using integrated bioinformatics methods.

Bioresponsive cisplatin crosslinked albumin hydrogel served for efficient cancer combination therapy

Combination therapy is one of the potential strategies for tackling complicated tumor treatments like drug resistance.In this work,we have generated a therapeutic cisplatin-crosslinked albumin hydrogel(BC-Gel)that allows the local release of L-Buthionine-sulfoximine(BSO),cisplatin,and glucose oxidase(GOx)with distinct release kinetics.The BC-Gel with favorable biostimuli degradability and injectability could release therapeutic agents in a programmed manner within the tumor microenvironment(TME).The preferentially released BSO significantly suppressed the glutathione(GSH)-related cisplatin resistance and sensitized the tumor cells to cisplatin by inhibiting theγ-glutamylcysteine synthetase.Meanwhile,cisplatin achieved a sequential release and long-term treatment following the bioresponsive gel degradation under the combined action of chloride ions(Cl−)and proteinase in the body.In addition,the overproduced H_(2)O_(2)of GOx-catalyzed glucose oxidation accelerated the depletion of existed GSH within cells and further weakened the cisplatin resistance,achieving enhanced tumor treatment together with a strong cell-killing effect.The above sequential drug release strategy based on the dual GSH depletion effect breaks the balance of the GSH-mediated redox TME and enhances the sensitivity of A549 cells to cisplatin forcefully,and provides a promising way for temporal control of drug release as well as efficient cancer combination therapy.

Meiotic nuclear divisions 1(MND1)fuels cell cycle progression by activating a KLF6/E2F1 positive feedback loop in lung adenocarcinoma

Background:Considering the increase in the proportion of lung adenocarcinoma(LUAD)cases among all lung cancers and its considerable contribution to cancer-related deaths worldwide,we sought to identify novel oncogenes to provide potential targets and facilitate a better understanding of the malignant progression of LUAD.Methods:The results from the screening of transcriptome and survival analyses according to the integrated Gene Expression Omnibus(GEO)datasets and The Cancer Genome Atlas(TCGA)data were combined,and a promising risk biomarker called meiotic nuclear divisions 1(MND1)was selectively acquired.Cell viability assays and subcutaneous xenograftmodelswere used to validate the oncogenic role ofMND1 in LUADcell proliferation and tumor growth.Aseries of assays,including mass spectrometry,co-immunoprecipitation(Co-IP),and chromatin immunoprecipitation(ChIP),were performed to explore the underlying mechanism.Results:MND1 up-regulation was identified to be an independent risk factor for overall survival in LUAD patients evaluated by both tissue microarray staining and third party data analysis.In vivo and in vitro assays showed that MND1 promoted LUAD cell proliferation by regulating cell cycle.The results of the Co-IP,ChIP and dual-luciferase reporter assays validated that MND1 competitively bound to tumor suppressor Kruppel-like factor 6(KLF6),and thereby protecting E2F transcription factor 1(E2F1)from KLF6-induced transcriptional repression.Luciferase reporter and ChIP assays found that E2F1 activated MND1 transcription by binding to its promoter in a feedback manner.Conclusions:MND1,KLF6,and E2F1 form a positive feedback loop to regulate cell cycle and confer DDP resistance in LUAD.MND1 is crucial for malignant progression and may be a potential therapeutic target in LUAD patients.