Project description:Radiotherapy and adjuvant cisplatin (DDP) chemotherapy are standard administrations applied in the treatment of NPC. However, molecular change and functions of DDP chemo-resistance in nasopharyngeal carcinoma are still poorly understood.
Project description:Cisplatin (CDDP) is a widely used agent in the treatment of neuroblastoma. Unfortunately, the development of acquired chemoresistance limits its clinical use. To gain a detailed understanding of the mechanisms underlying the development of such chemoresistance, we comparatively analysed established cisplatin-resistant neuroblastoma cell line (UKF-NB- 4CDDP) and its sensitive counterpart (UKF-NB-4). We confirmed the decreased sensitivity of tested cells to cisplatin and identified a cross-resistance to carboplatin and oxaliplatin. Among the proteins responsible for UKF-NB-4CDDP chemoresistance, ion channels transport family proteins, ABC superfamily proteins, SLC-mediated trans-membrane transporters, proteasome complex subunits and V-ATPases were identified. Moreover, we detected markedly higher proteasome activity in UKF-NB-4CDDP cells and a remarkable lysosomal enrichment that can be inhibited by bafilomycin A to sensitize UKF-NB-4CDDP to CDDP. Our results indicate that lysosomal sequestration and proteasome activity may be one of key mechanisms responsible for intrinsic chemoresistance of neuroblastoma to CDDP.
Project description:The development of therapeutic resistance and metastatic dissemination takes place in 20-30% patients with nasopharyngeal carcinoma (NPC), resulting in poor survival. Hence, a better understanding of the underlying molecular mechanisms will help improve clinical outcome. We have identified a novel circRNA, circIPO7, as a promoter of metastasis and cisplatin chemoresistance in NPC cells. Expression profiling and Genome binding/occupancy profiling by high throughput sequencing were performed to explore the underlying molecular mechanisms.
Project description:Cancer stem cells (CSCs) possess self-renewal and chemoresistance activities. However, the manner in which these features are maintained remains obscure. We sought to identify cell surface protein(s) that mark self-renewing and chemoresistant gastric cancer cells using the Explorer Antibody Microarray. We identified PMP22, a target gene of the Wnt/β-catenin pathway, as the most upregulated cell surface protein in gastric cancer xenografts exposed to cisplatin (DDP). PMP22 expression was markedly upregulated in tumorspheric cells and declined with differentiation. Infecting gastric cancer cells with lentivirus expressing PMP22 shRNAs reduced proliferation, tumorsphere formation, and chemoresistance to cisplatin in vitro and in NOD/SCID mice. When combined with bortezomib, a PMP22 inhibitor, the chemotherapeutic sensitivity to cisplatin treatment was dramatically increased by inducing cell apoptosis in cultured cells and xenograft mouse models. Finally, mRNA expression levels of PMP22 were detected in 38 tumor specimens from patients who received 6 cycles of perioperative chemotherapy. A strong correlation between PMP22 level and tumor recurrence was revealed, thus showing a pivotal role of PMP22 in the clinical chemoresistance of gastric cancer. Our study is the first to show the role of PMP22 in gastric cancer stemness and chemoresistance and reveals a potential new target for the diagnosis and treatment of recurrent gastric cancer.
Project description:Chemoresistance frequently leads to therapeutic failure in tongue squamous cell carcinoma (TSCC). Increasing evidence has shown that Long noncoding RNAs (lncRNAs) play pivotal roles in biological properties of cancer. However, the roles and mechanisms of lncRNAs in cisplatin resistance are not well understood. In this study, to identify the lncRNAs induced by chemotherapy, we profile the expression of lncRNAs in cisplatin-resistant TSCC cells using LncRNA microarrays.
Project description:Increasing evidence has shown that chemoresistance is related to the process of epithelial-mesenchymal transition (EMT) and increased invasiveness by tongue squamous cell carcinoma (TSCC) cells. Long noncoding RNAs (lncRNAs) play pivotal roles in tumour metastasis and progression. However, the roles and mechanisms of lncRNAs in cisplatin resistance induced EMT and metastasis are not well understood. In this study, a Chemotherapy Induced Long non-coding RNA 1 (CILA1) was discovered by using microarrays and was functionally identified as a regulator of chemo-sensitivity in TSCC cells.Upregulation of CILA1 promotes EMT, invasiveness and chemoresistance in TSCC cells, whereas the inhibition of CILA1 expression induces MET and chemosensitivity and inhibis the invasiveness of cisplatin-resistant cells both in vitro and in vivo. We also found that CILA1 exerts its functions via the activation of the Wnt/ β-catenin signalling pathway.High CILA1 expression levels and low levesl of phosphorylated β-catenin were closely associated with cisplatin-resistance and advanced disease stage, and were predictors of poor prognosis in TSCC patients. These findings provided a new biomarker for Increasing evidence has shown that chemoresistance is related to the process of epithelial-mesenchymal transition (EMT) and increased invasiveness by tongue squamous cell carcinoma (TSCC) cells. Long noncoding RNAs (lncRNAs) play pivotal roles in tumour metastasis and progression. However, the roles and mechanisms of lncRNAs in cisplatin resistance induced EMT and metastasis are not well understood. In this study, a Chemotherapy Induced Long non-coding RNA 1 (CILA1) was discovered by using microarrays and was functionally identified as a regulator of chemo-sensitivity in TSCC cells.Upregulation of CILA1 promotes EMT, invasiveness and chemoresistance in TSCC cells, whereas the inhibition of CILA1 expression induces MET and chemosensitivity and inhibis the invasiveness of cisplatin-resistant cells both in vitro and in vivo. We also found that CILA1 exerts its functions via the activation of the Wnt/ β-catenin signalling pathway.High CILA1 expression levels and low levesl of phosphorylated β-catenin were closely associated with cisplatin-resistance and advanced disease stage, and were predictors of poor prognosis in TSCC patients. These findings provided a new biomarker for the chemosensitivity of TSCC tumours and a therapeutic target for TSCC treatment.
Project description:Multiple DNA methylation changes have been associated with the acquisition of drug resistance; however it remains uncertain how many of these changes may represent critical DNA methylation drivers of chemoresistance. Using genome-wide DNA methylation profiling across 27,578 CpG sites on Illumina HumanMethylation27 bead array we identified loci at 4092 genes becoming hypermethylated in the chemoresistant A2780/cp70 ovarian tumour cell line compared to the parental sensitive A2780 line. Hypermethylation at CpG islands (CGI) is often associated with transcriptional silencing, however only 245 of these hypermethylated genes become down-regulated in A2780/cp70 as measured by microarray expression profiling. Treatment with the demethylating agent Decitabine induces re-sensitisation to cisplatin and resulted in re-expression of 41 of the down-regulated genes in cisplatin-resistant cells at the time point when re-sensitisation occurs. 13 of the 41 genes were consistently hypermethylated in two further independent cisplatin-resistant A2780 cell derivatives. Nine out of the 13 genes (ARHGDIB, ARMCX2, COL1A, FLNA, FLNC, MEST, MLH1, NTS, PSMB9) acquired methylation at CpG sites in ovarian tumours at relapse following chemotherapy or chemoresistant cell lines derived at the time of patient relapse. Furthermore, 5/13 candidate genes acquired methylation in drug-resistant in vivo-derived ovarian cancer sustaining (side population) cells. Therefore, this small set of genes are potential key drivers of chemoresistance and should be further evaluated as predictive biomarkers, both to existing chemotherapies, but also to epigenetic therapies used to modulate drug resistance. Array-based methylation profiling was performed using the Infinium HumanMethylation27 BeadChip in two cisplatin sensitive cell lines and three cisplatin resistant cell lines derived in vitro, four pairs of cisplatin sensitive and resistant cell lines derived in vivo, 7 pairs of tumour tissues obtained from patients before chemotherapy and at disease relapse, 2 pairs of IGROV1 SP and NSP cells. The reproducibility of the Infinium HumanMethylation27 BeadChips was evaluated using biological and technical replicates of matched chemosensitive/chemoresistant ovarian cancer cell lines PEO1/PEO4. Differential methylation cutoff was estimated from two biological replicates by bootstrap resampling.
Project description:chemoresistance frequently leads to therapeutic failure in oral squamous cell carcinoma (OSCC). Recently, studies have reported that lncRNAs play active roles in regulation biological properties of cancer. To understand whether lncRNAs involve in regulating cisplatin sensitivity in TSCC, in this study, we profiled the expression of lncRNAs in two TSCC cell lines(CAL-27 and SCC-9) under cisplatin treatment paired untreated cell lines by LncRNA Array (ArrayStar V3.0).