Oxaliplatin induces different cellular and molecular chemoresistance patterns in colorectal cancer cell lines of identical origins

Abstract

BackgroundCancer cells frequently adopt cellular and molecular alterations and acquire resistance to cytostatic drugs. Chemotherapy with oxaliplatin is among the leading treatments for colorectal cancer with a response rate of 50%, inducing intrastrand cross-links on the DNA. Despite of this drug’s efficiency, resistance develops in nearly all metastatic patients. Chemoresistance being of crucial importance for the drug’s clinical efficiency this study aimed to contribute to the identification and description of some cellular and molecular alterations induced by prolonged oxaliplatin therapy. Resistance to oxaliplatin was induced in Colo320 (Colo320R) and HT-29 (HT-29R) colorectal adenocarcinoma cell lines by exposing the cells to increasing concentrations of the drug. Alterations in morphology, cytotoxicity, DNA cross-links formation and gene expression profiles were assessed in the parental and resistant variants with microscopy, MTT, alkaline comet and pangenomic microarray assays, respectively.ResultsMorphology analysis revealed epithelial-to-mesenchymal transition in the resistant vs parental cells suggesting alterations of the cells’ adhesion complexes, through which they acquire increased invasiveness and adherence. Cytotoxicity measurements demonstrated resistance to oxaliplatin in both cell lines; Colo320 being more sensitive than HT-29 to this drug (P < 0.001). The treatment with oxaliplatin caused major DNA cross-links in both parental cell lines; in Colo320R small amounts of DNA cross-links were still detectable, while in HT-29R not. We identified 441 differentially expressed genes in Colo320R and 613 in HT-29R as compared to their parental counterparts (at least 1.5 -fold up- or down- regulation, p < 0.05). More disrupted functions and pathways were detected in HT-29R cell line than in Colo320R, involving genes responsible for apoptosis inhibition, cellular proliferation and epithelial-to-mesenchymal transition. Several upstream regulators were detected as activated in HT-29R cell line, but not in Colo320R.ConclusionsOur findings revealed a more resistant phenotype in HT-29R as compared to Colo320R and different cellular and molecular chemoresistance patterns induced by prolonged treatment with oxaliplatin in cell lines with identical origins (colorectal adenocarcinomas).

Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

“…The role of elevated NF-κB activity in the resistance of CRC cells to OXA-induced cell death was previously demonstrated 30 and in agreement with other studies 40 , results presented here indicate that NF-κB is constitutively active in all the CRC cell lines examined; however, we found that those cell lines with acquired resistance to OXA exhibited an increased activation of this pathway as compared to their matched sensitive parental cells, especially the HTOXAR3 resistant model, suggesting a role for NF-κB and its downstream targets in the development of the drug-resistant phenotype. This fact was reported to be associated with the acquisition of a mesenchymal phenotype along the OXA-resistance acquisition process 41 42 and according to this, our exploratory functional enrichment analysis revealed EMT as one of the top hallmarks in the list of genes that were up-regulated in HTOXAR3 cell line in comparison with HT29 cells ( Supplementary Table S3 ). Therefore our results could be explained in part by an EMT process in OXA resistant cells.…”

“…Three NF-κB-transcriptionally regulated CXC-chemokines, CXCL8 , CXCL1 and CXCL2 , were highly overexpressed as a result of OXA-resistance acquisition in the HTOXAR3 cell line and at the same time were specifically down-regulated after treatment with OXA plus Curcumin in these cells. These pro-inflammatory chemokines play an important role in regulating CRC progression, angiogenesis and metastasis 51 , processes that have been associated with OXA resistance 42 . The effect of chemotherapy on CXCL8 52 53 , CXCL1 and CXCL2 54 gene transcription has been described elsewhere.…”

Epithelial to mesenchymal transition is associated with rapamycin resistance

“…EMT has been associated with chemoresistance to several chemotherapeutic agents including paclitaxel [ 36 ], oxaliplatin [ 37 ], gemcitabine [ 38 ], 5-fluororacil [ 39 ] as well as targeted therapies such as tamoxifen [ 40 ], erlotinib and PI3K/Akt inhibitors [ 21 ]. RNA-based multiplex predictors such as Oncotype Dx Recurrence Score and MammaPrint have been effectively transitioned to clinical use; thus, it would be important to determine whether a RNA- or protein-based predictor can indeed have predictive utility.…”

Novel Palladium(II) Complexes that Influence Prominin-1/CD133 Expression and Stem Cell Factor Release in Tumor Cells

“…Cytotoxicity evaluations were done with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test (Sigma-Aldrich) for HT-29, DLD-1, CSC and LIV cells. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H -tetrazolium/phenazine methosulfate (MTS/PMS) (Promega Corporation, Madison, WI, USA) colorimetric cell proliferation assay was done on normal human lymphocytes, following a protocol established previously [ 49 ]. Briefly, cells were seeded in triplicate in 96-well flat-bottom plates, at a cell population density of 2 × 10 4 and 15 × 10 3 for MTT and MTS/PMS assays, respectively.…”