DDP Resistance In Gastric Cancer Cells Research Articles

Tanshinone I Stimulates Pyroptosis of Cisplatin-Resistant Gastric Cancer Cells by Activating the NF-κB/Caspase-3(8)/GSDME Signaling Pathway.

Cisplatin (DDP) resistance frequently occurs in gastric cancer (GC) therapy. Tanshinone I is a liposoluble phenanthraquinone compound present in the roots of Salvia miltiorrhiza Bunge (Danshen). In this study, we aimed to explore the effects of tanshinone I on modulating DDP resistance of GC cells in vitro and in vivo. DDP-resistant GC cell models (BGC823/DDP and SGC7901/DDP) were established, and their viability, proliferation, migration, lactate dehydrogenase activity, reactive oxygen species (ROS) generation, and pyroptosis were assessed after DDP treatment with or without tanshinone I. In addition, a mouse model with subcutaneously transplanted GC tumors was established to confirm the effects of tanshinone I and DDP on tumor growth and cell pyroptosis. The results revealed that tanshinone I inhibited DDP-resistant GC cell proliferation and migration; increased intracellular ROS levels; and activated cell pyroptosis by enhancing the levels of cleaved caspase-8, cleaved caspase-3, GSDME-NT, phospho-IKK-α/β, and nuclear factor kappa-B (NF-κB). GSDME knockdown weakened these effects of tanshinone I on DDP-resistant GC cells. Furthermore, DDP combined with tanshinone I inhibited the growth of subcutaneously transplanted GC tumors in mice by reducing cell proliferation and inducing pyroptosis. In conclusion, tanshinone I reversed DDP resistance of GC cells by stimulating pyroptosis, by activating NF-κB/caspase-3(8)/GSDME signaling pathway.

Gastric cancer derived mesenchymal stem cells promoted DNA repair and cisplatin resistance through up-regulating PD-L1/Rad51 in gastric cancer

Chemotherapy resistance in advanced gastric cancer (GC) patients has largely limited the effectiveness of therapy, resulting in disease recurrence and poor prognosis. Gastric cancer derived mesenchymal stem cells (GCMSC) are widely believed to promote GC invasion, metastasis and immune escape via up-regulating programmed death ligand 1 (PD-L1). However, the mechanism by which PD-L1 mediated by GCMSC might regulate the chemoresistance is unknown in GC. Herein, higher half maximal inhibitory concentrations (IC50) and less apoptotic rate were observed in GCMSC conditioned medium (GCMSC-CM) treated GC cells exposed to cisplatin (DDP), along with high expression of multi-drug resistance 1 (MDR1) and DNA repair related genes such as Rad51. The knockdown of PD-L1 reversed the increase of Rad51 mediated by GCMSC-CM, resulting in the increased sensitivity of GC cells to DDP. In addition, inhibition of heat shock protein 90 (HSP90) regulated the expression of PD-L1 and Rad51, revealing the important role of HSP90 in GCMSC-CM mediated DDP resistance. Consistent with the observations in vitro, analysis of patient samples and xenograft models further confirmed that reduction of PD-L1 or HSP90 weakened DDP tolerance mediated by GCMSC-CM, along with decrease of Rad51 and MDR1. In conclusion, we demonstrated that GCMSC-CM enhanced DDP resistance in GC cells through regulating PD-L1-Rad51. It is the first to report this particular mechanism of DDP resistance induced by GCMSC in GC, suggesting a potential therapeutic targets for DDP resistant GC cells.

The Interaction Between SMAD1 and YAP1 Is Correlated with Increased Resistance of Gastric Cancer Cells to Cisplatin.

Drug resistance is a major obstacle leading to treating failure and poor outcome in gastric cancer (GC). This study explores the interaction between SMAD family member 1 (SMAD1) and Yes1-associated transcriptional regulator (YAP1) and their roles in cisplatin (DDP) resistance in GC. Transcriptome analysis predicted that SMAD1 is highly expressed in DDP-resistant cells. Elevated SMAD1 expression was detected in GC tissue and cells, especially in DDP-resistant cells (MKN-45/DDP and AGS/DDP). SMAD1 downregulation in cells decreased 50% inhibition value of DDP, reduced proliferation, migration, and invasion, and promoted cell cycle arrest and apoptosis. A protein-protein interaction network suggested a possible SMAD1 and YAP1 interaction in GC. The SMAD1 and YAP1 interaction was validated by chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP), and luciferase assays. SMAD1 bound to YAP1 and activated its transcription. SMAD1 formed complexes with YAP1 in nucleus, and YAP1 upregulation enhanced SMAD1 activity as well. Upregulation of YAP1 restored the malignant behaviors of GC cells suppressed by SMAD1 silencing. In vivo, SMAD1 silencing suppressed growth and DDP resistance of xenograft tumors in nude mice, and this suppression was blocked by YAP1 overexpression again. In conclusion, this study demonstrates that SMAD1 can interact with YAP1 to enhance the DDP resistance of GC cells.

LncRNA HLA Complex Group 11 Knockdown Alleviates Cisplatin Resistance in Gastric Cancer by Targeting the miR-144-3p/UBE2D1 Axis.

ObjectiveCisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). LncRNA noncoding RNA HLA complex group 11 (lncRNA HCG11) has been confirmed to promote GC progression. This study attempted to investigate the underlying molecular mechanism of HCG11 in DDP resistance of GC.MethodsqRT-PCR was performed to evaluate the expression of HCG11, microRNA-144-3p (miR-144-3p), and ubiquitin-conjugating enzyme E2 D1 (UBE2D1) in GC. The correlation between HCG11 and clinicopathological features of GC patients was assessed. DDP-resistant GC cells and their parental cells were cultured in different concentrations of DDP. The role of HCG11 for the viability and the half maximal inhibitory concentration (IC50) of DDP in DDP-resistant GC cells was determined by MTT assay. Then, the invasion of DDP-resistant GC cells was measured by transwell assay. Next, a dual-luciferase reporter assay was used to confirm the interactions among HCG11, miR-144-3p, and UBE2D1 in GC.ResultsThe expression of HCG11 and UBE2D1 was elevated in tumor tissues of GC patients, but miR-144-3p was declined. HCG11 expression was elevated in DDP-resistant GC patients and is strongly correlated with DDP sensitivity and World Health Organization grade in GC patients. HCG11 knockdown reduced the viability, IC50 of DDP, and invasion of DDP-resistant GC cells. Additionally, HCG11 targeted miR-144-3p and miR-144-3p further targeted UBE2D1. Feedback experiments indicated that low expression of miR-144-3p or overexpression of UBE2D1 mitigated the inhibitory effect of HCG11 depletion on DDP resistance of GC cells.ConclusionHCG11 knockdown attenuated DDP resistance of GC cells through via miR-144-3p/UBE2D1 axis, affording a novel therapeutic strategy for GC.

HCP5 contributes to cisplatin resistance in gastric cancer through miR-128/HMGA2 axis

ABSTRACT The long non-coding RNA HLA complex P5 (HCP5) is extensively related to cancer chemoresistance, while its function in gastric cancer (GC) has not been well elucidated yet. Here, the role and mechanism of HCP5 in regulating the chemoresistance of GC to cisplatin (DDP) was investigated. Our results revealed that HCP5 was increased in GC patients and indicated a poor prognosis. HCP5 knockdown weakens DDP resistance and reduced apoptosis of GC cells. miR-128 was decreased in GC patients and sponged by HCP5. HMGA2 was targeted by miR-128 and was increased in GC patients. HCP5 aggravated the resistance of GC cells to DDP in vitro by elevating HMGA2 expression via sponging miR-128. HCP5 silencing inhibited GC cells growth, resistance to DDP, and Ki-67 expression in vivo. In summary, HCP5 contributed to DDP resistance in GC cells through miR-128/HMGA2 axis, providing a promising therapeutic target for GC chemoresistance.

Circular RNA circVAPA promotes chemotherapy drug resistance in gastric cancer progression by regulating miR-125b-5p/STAT3 axis.

BACKGROUNDGastric cancer (GC) is a prevalent malignancy, leading to a high incidence of cancer-associated death. Cisplatin (DDP)-based chemotherapy is the principal therapy for clinical GC treatment, but DDP resistance is a severe clinical challenge and the mechanism remains poorly understood. Circular RNAs (circRNAs) have been identified to play crucial roles in modulating the chemoresistance of gastric cancer cells.AIMTo explore the effect of circVAPA on chemotherapy resistance during GC progression.METHODSThe effect of circVAPA on GC progression and chemotherapy resistance was analyzed by MTT assay, colony formation assay, Transwell assay, wound healing assay, and flow cytometry analysis in GC cells and DDP resistant GC cell lines, and tumorigenicity analysis in nude mice in vivo. The mechanism was investigated by luciferase reporter assay, quantitative real-time PCR, and Western blot analysis. RESULTSCircVAPA expression was up-regulated in clinical GC tissues compared with normal samples. CircVAPA depletion inhibited proliferation, migration, and invasion and increased apoptosis of GC cells. The expression of circVAPA, STAT3, and STAT3 downstream genes was elevated in DDP resistant SGC7901/DDP cell lines. CircVAPA knockdown attenuated the DDP resistance of GC cells. Mechanically, circVAPA was able to sponge miR-125b-5p, and miR-125b-5p could target STAT3 in the GC cells. MiR-125b-5p inhibitor reversed circVAPA depletion-enhanced inhibitory effect of DDP on GC cells, and STAT3 knockdown blocked circVAPA overexpression-induced proliferation of DDP-treated SGC7901/DDP cells. The depletion of STAT3 and miR-125b-5p inhibitor reversed circVAPA depletion-induced GC cell apoptosis. Functionally, circVAPA contributed to the tumor growth of SGC7901/DDP cells in vivo.CONCLUSIONCircVAPA promotes chemotherapy resistance and malignant progression in GC by miR-125b-5p/STAT3 signaling. Our findings present novel insights into the mechanism by which circVAPA regulates chemotherapy resistance of GC cells. CircVAPA and miR-125b-5p may be considered as the potential targets for GC therapy.

HCP5 Promotes Proliferation and Contributes to Cisplatin Resistance in Gastric Cancer Through miR-519d/HMGA1 Axis.

IntroductionThe long-non-coding RNA HCP5 (HLA complex P5) has been extensively linked to the ability of cancer cells to resist chemotherapeutic interventions. Here, we investigated the role of HCP5 in gastric cancer (GC) which to-date has been poorly characterized. Our results indicated that HCP5 expression was up-regulated in GC cells.MethodsHCP5, miR-519d, and high mobility group A1 (HMGA1) expression levels in GC cells were measured using quantitative real-time PCR (qRT-PCR) and Western blot analysis. Drug sensitivity and apoptosis of tumor cells were assessed using cell counting kit-8, flow cytometry, and caspase activity assay. Bioinformatics and luciferase reporter assays were employed for analyzing the interactions between HCP5, miR-519d, and HMGA1.ResultsHCP5 knockdown suppressed proliferation and weakened the resistance to cisplatin (DDP) of GC cells. miR-519d was down-regulated in GC cells and sponged by HCP5. HMGA1 was directly inhibited by miR-519d and its expression was up-regulated in GC cells. HCP5 exacerbated the resistance to cisplatin of GC cells in vitro by enhancing HMGA1 expression via sponging miR-519d.ConclusionIn summary, HCP5 promoted proliferation and contributed to DDP resistance in GC cells through miR-519d/HMGA1 axis.

CircRNA DONSON contributes to cisplatin resistance in gastric cancer cells by regulating miR-802/BMI1 axis

BackgroundCircular RNA downstream neighbor of SON (circDONSON) has been revealed to promote gastric cancer (GC) growth and invasion, while the role and molecular mechanism underlying circDONSON in GC cisplatin (DDP) resistance remain unclear.MethodsLevels of circDONSON, microRNA (miR)-802, and B lymphoma Mo-MLV insertion region 1 (BMI1) mRNA were detected using quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit-8 assay, colony formation assay and flow cytometry, respectively. Protein levels of BMI1, Cyclin D1, p27, Caspase-3 Cleavage and Caspase-9 Cleavage were determined by western blot. The interaction between miR-802 and circDONSON or BMI1 was confirmed by dual-luciferase reporter assay. In vivo experiments were conducted via the murine xenograft model.ResultsCircDONSON was elevated in GC tissues and cell lines, especially in DDP-resistant GC tissues and cells. Knockdown of circDONSON sensitized GC cells to DDP by inhibiting cell viability and promoting cell apoptosis in vitro. Further mechanism-related investigations suggested that circDONSON functioned as “sponge” by competing for miR-802 binding to modulate its target BMI1. Silencing miR-802 reversed the inhibition of DDP-resistance in GC cells induced by circDONSON down-regulation. Besides, miR-802 alleviated DDP resistance in GC cells by targeting BMI1. Functionally, circDONSON knockdown enhanced the cytotoxicity of DDP in GC in vivo.ConclusionOur findings demonstrated circDONSON promoted cisplatin resistance in gastric cancer cells by regulating miR-802/BMI1 axis, shedding light on the development of a novel therapeutic strategy to overcome chemoresistance in gastric cancer patients.

MiR-21 modulates cisplatin resistance of gastric cancer cells by inhibiting autophagy via the PI3K/Akt/mTOR pathway.

Resistance to cisplatin (DDP) remains a major obstacle in the control of gastric cancer (GC) progression. A previous study revealed that microRNA-21 (miR-21) contributes to DDP resistance in GC cells via the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway. The aim of the current study was to explore the mechanisms underlying the cytoprotective function of miR-21. In this study, DDP-resistant GC cells were obtained by continuous exposure of human gastric adenocarcinoma cells to increasing concentrations of DDP. Western blot analysis was used to evaluate activation of the PI3K/Akt/mechanistic target of rapamycin kinase (mTOR) pathway. The level of miR-21 was altered by transfection of miR-21 mimic and inhibitor. Autophagy was assessed by detecting autophagosome formation, Beclin-1 and LC3 expression. An Annexin V-propidium iodide assay was performed to estimate the survival and death of GC cells. GC cells became refractory to the growth inhibition and apoptosis induced by DDP treatment, activation of Akt and mTOR were increased in DDP-resistant GC cells. Inhibition of autophagy decreased the sensitivity of GC cells to DDP, and autophagy induction produced the opposite effect. DDP-resistant GC cells expressed higher levels of miR-21 compared with the parent cells. Transfection of GC cells with miR-21 mimics contributed to restored DDP resistance by suppressing autophagy, while miR-21 inhibitor sensitized DDP-resistant GC cells by promoting autophagy. In conclusion, the results demonstrated that miR-21 is associated with DDP resistance in GC cells by inhibiting autophagy via the PI3K/Akt/mTOR pathway, and autophagy inducers could be therapeutic targets for the effective treatment of DDP resistance in GC.

MiR-187 influences cisplatin-resistance of gastric cancer cells through regulating the TGF-β/Smad signaling pathway.

To explore the effect of micro-ribonucleic acid (miR)-187 on cisplatin (DDP) resistance of gastric cancer cells by regulating the transforming growth factor-β (TGF-β)/Smad signaling pathway. DDP-sensitivities in GES-1, SGC7901, and SGC7901/DDP cells were detected via Cell Counting Kit-8 (CCK-8) assay. The differential expression of miR-187 of these cell lines was detected by Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR). DDP-resistant gastric cancer cells SGC7901/DDP were divided into control group (blank control), miR-187 inhibitor group (SGC7901/DDP cells transfected with miR-187 inhibitor), and miR-187 mimic group (SGC7901/DDP cells transfected with miR-187 mimic). The protein expressions of miR-187, TGF-β1, p-Smad4, excision repair cross-complementation group 3 (ERCC3), and ERCC4 were determined through RT-qPCR, immunohistochemistry, and Western blotting. The apoptosis in each group was detected by flow cytometry. MiR-187 level had a negative correlation with DDP-resistance of GES-1, SGC7901, and SGC7901/DDP cells, and among them, the GES-1 cells had the lowest DDP-resistance and the highest expression of miR-187. CCK-8 assay revealed that compared with that in the control group, DDP-resistance significantly declined in the miR-187 mimic group, while it was significantly enhanced in miR-187 inhibitor group (p<0.01). According to the results of flow cytometry, after treatment with 100 nM DDP for 12 h, the apoptotic rate in miR-187 mimic group enhanced, while it was markedly reduced in the miR-187 inhibitor group (p<0.01). Western blotting and immunohistochemistry results showed that expressions of TGF-β1 and p-Smad4 were significantly downregulated in the miR-187 mimic group, while they were upregulated in the miR-187 inhibitor group (p<0.01). Besides, compared with the control group, ERCC3 and ERCC4 were downregulated in the miR-187 mimic group, while upregulated in miR-187 inhibitor group (p<0.01). The overexpression of miR-187 alleviates DDP-resistance in gastric cancer cells by inhibiting the TGF-β/Smad signaling pathway.

PCAT-1 contributes to cisplatin resistance in gastric cancer through miR-128/ZEB1 axis

Increasing evidence suggests that dysregulation of long non-coding RNAs (lncRNAs) is implicated with chemoresistance in cancers. However, their function and molecular mechanisms in gastric cancer (GC) chemoresistance remain not well elucidated. In this study, we aimed to investigate the functional role and the underlying molecular mechanism of lncRNA prostate cancer-associated transcript 1 (PCAT-1) in cisplatin (DDP) resistance of GC. Our results revealed that PCAT-1 was up-regulated in DDP-resistant GC tissues and cells. GC patients with high PCAT-1 expression levels had a poor prognosis. Knockdown of PCAT-1 facilitated the sensitivity of DDP-resistant GC cells to DDP. Additionally, PCAT-1 functioned as a sponge of miR-128 in GC cells. Moreover, inhibition of miR-128 reversed the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. In addition, ZEB1 was identified as a target of miR-128, and overexpression of ZEB1 could block the inductive effect of PCAT-1 knockdown on DDP sensitivity of GC cells. Besides, PCAT-1 knockdown enhanced DDP sensitivity in tumors in vivo. In summary, PCAT-1 confers DDP resistance in GC cells through miR-128/ZEB1 axis, providing a promising therapeutic strategy for GC.

Effect of PLK1 inhibition on cisplatin-resistant gastric cancer cells.

This study aims to investigate the effect of polo-like kinase 1 (PLK1) inhibition on cisplatin (DDP)-resistant gastric cancer (GC) cells. The transcriptional level of PLK1 was measured by quantitative reverse-transcription polymerase chain reaction. Expressions of PLK1 and its downstream mediators as well as autophagy-related protein LC3 I/LC3 II were detected by western blot. An 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 5-ethynyl-2'-deoxyuridine immunofluorescent staining were conducted to evaluate the cell viability and replication activity separately. Flow cytometry was carried out to determine the cell cycle status. TheGFP-LC3 vector contributed toward tracking the formation and aggregation of autophagosomes. Drug-resistant SGC-7901/DDP cells showed insignificant changes in all phases after DDP treatment, including DNA replication, cell proliferation, cell cycle, and apoptosis, whereas DDP could significantly improve the autophagy level of SGC-7901/DDP as well as PLK1expression. By downregulating the expression of PLK1, both BI2536 andsi-PLK1 enhanced SGC-7901/DDP sensitivity to DDP, suppressing the proliferation and autophagy as well as improving the apoptosis rate. PLK1 inhibition also resulted in the repression of cell division regulators CDC25C and cyclin B1. Together, our experimental results illustrated that the DDP resistance of GC cells might be associated with the aberrant overexpression of PLK1. PLK1 inhibition, including si-PLK1 and BI2536 treatment, could restore the chemosensitivity of drug-resistant SGC-7901/DDP cells and enhance the efficacy of DDP, revealing the potential value of PLK1 inhibition in GC chemotherapy.

MiR-223 promotes the cisplatin resistance of human gastric cancer cells via regulating cell cycle by targeting FBXW7.

BackgroundIncreasing evidence showed that miRNAs serve as modulators of human cancer, either as oncogene or tumor suppressors. Cisplatin resistance is the most common cause of chemotherapy failure in gastric cancer (GC). However, the roles of miRNAs in cisplatin resistance of GC remain largely unknown. The aim of the study was to identify a novel miRNA/gene pathway that regulates the sensitivity of GC cells to cisplatin.MethodsIn this study, we chose miR-223 by qRT-PCR analysis, the most significantly up-regulated miRNA in GC, to investigate its formation of DDP-resistant phenotype of GC cells and possible molecular mechanisms.ResultsWe found that miR-223 was most significantly up-regulated miRNA in DDP-resistant GC cells compared with parental GC cells. Besides, its expression was also significantly up-regulated in GC tissues. FBXW7 was identified as the direct and functional target gene of miR-223. Overexpression of FBXW7 could mimic the effect of miR-223 down-regulation and silencing of FBXW7 could partially reverse the effect of miR-223 down-regulation on DDP resistance of DDP-resistant GC cells. Besides, miR-223 and FBXW7 could affect the G1/S transition of cell cycle by altering some certain cell cycle regulators. Furthermore, miR-223 was found to be significantly up-regulated in H. pylori infected tissues and cells, suggesting that H. pylori infection may lead to GC development and DDP resistance.ConclusionsOur findings revealed the roles of miR-223/FBXW7 signaling in the DDP resistance of GC cells and targeting it will be a potential strategic approach for reversing the DDP resistance in human GC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0145-6) contains supplementary material, which is available to authorized users.