Project description:Purpose: Chemotherapy is pivotal in the multimodal treatment of pancreatic cancer patients. In recent years, technical advances have developed experimental methods that unveiled a high degree of inter- and intratumoral heterogeneity in pancreatic cancer. We hypothesized that intratumoral heterogeneity (ITH) impacts response to gemcitabine treatment and demands specific targeting of resistant subclones. Experimental Design: We addressed the effect of ITH on response to gemcitabine treatment using single cell-derived cell lines (SCDCL) from the classical-like cell line BxPC3 and the basal-like cell line Panc-1 which were analyzed by mRNA-seq and mass spectrometry. Results: Individual SCDCLs of the parental tumor cell populations of BxPC3 and Panc-1 showed considerable heterogeneity in response to gemcitabine. Unsupervised principal component analysis (PCA) including the 1,000 most variably expressed genes showed a clustering of the SCDCLs according to their respective sensitivity to gemcitabine treatment for BxPC3, while this clustering was less clear for Panc-1. In BxPC3 SCDCLs, enriched signaling pathways EMT, TNF signaling via NfKB, and IL2STAT5 signaling correlated with more resistant behavior to gemcitabine. In Panc-1 SCDCLs MYC targets V1 and V2 as well as E2F targets were associated with stronger resistance to gemcitabine. Feature extraction of proteomes again identified less proteins whose expression was associated with the response of individual SCDCLs in Panc-1 compared to BxPC3. Based on molecular profiles, we could show that the gemcitabine-resistant SCDCLs of both BxPC3 and Panc-1 are more sensitive to the BET inhibitor JQ1 compared to the respective gemcitabine-sensitive SCDCLs. Conclusions: Our model system of SCDCLs identified gemcitabine-resistant subclones within a parental tumor population and provides evidence for the critical role of ITH for treatment response in pancreatic cancer. Through molecular profiling, we identified specific signaling pathways and protein signatures that might help to explain the differential response to treatment among clones. We exploited these molecular differences for an improved and more targeted therapy of resistant subclones of a heterogeneous tumor.
Project description:Gemcitabine has been a first-line therapeutic agent for pancreatic ductal adenocarcinoma (PDAC) pancreatic cancer; however, acquisition of resistance to gemcitabine remains a major challenge. We analyzed miRNAs expression profiles by array-based miRNAs analysis between gemcitabine–resistant (PANC-1/GEM) and parental PANC-1 cells.
Project description:Gemcitabine resistance is currently the main problem of chemotherapy for advanced pancreatic cancer patients. The resistance is thought to be caused by altered drug metabolism or reduced apoptosis of cancer cells. However, the underlying mechanism of Gemcitabine resistance in pancreatic cancer remains unclear. In this study, we established Gemcitabine resistant PANC-1 (PANC-1-GR) cell lines and compared the circular RNAs (circRNAs) profiles between PANC-1 cells and PANC-1-GR cells by RNA sequencing.
Project description:No reliable predictors of susceptibility to gemcitabine chemotherapy exist in pancreatic ductal adenocarcinoma. MicroRNAs (miR) are epigenetic gene regulators with tumorsuppressive or oncogenic roles in various carcinomas. This study assesses chemoresistant PDAC for its specific miR expression pattern. Gemcitabine-resistant variants of two mutant p53 human pancreatic adenocarcinoma cell lines were established. MicroRNA screening was investigated by microarray. Gemcitabine-resistant PANC-1 (PANC-1-GR) and MIA-PaCa-2 (MIA-PaCa-2-GR) cell clones were produced by exposing the parental cells to repeated pulsatile gemcitabine treatment over 3 days with constant sublethal concentrations followed by recovery-periods with agent-free medium until the cells recovered exponentially. Parental PANC-1 cells were treated with 0.4µM gemcitabine cycles for approximately 9 months. Parental MIA-PaCa-2 cells were exposed to 0.06µM gemcitabine cycles for approximately 12 months. Affymetrix GeneChip miRNA microarrays (Affymetrix UK Ltd., High Wycombe, UK) were performed in parental and chemoresistant PANC-1 and MIA-PaCa-2 cells after 29 chemotherapy cycles using the manufacturers´ protocols. The samples were prepared from 1µg of total-RNA in accordance with the Affymetrix FlashTag Biotin HSR RNA Labeling Kit. The targets were hybridized overnight to Affymetrix GeneChip miRNA arrays. Following hybridization, the arrays were washed and stained using the Affymetrix GeneChip Fluidics Station 450 and scanned using the Affymetrix GeneChip Scanner 3000 7G. Microarray data quality was checked as recommended by the manufacturer and by the quality metrics in the Partek Genomics Suite software (Partek Inc., St. Louis, MO).
Project description:No reliable predictors of susceptibility to gemcitabine chemotherapy exist in pancreatic ductal adenocarcinoma. MicroRNAs (miR) are epigenetic gene regulators with tumorsuppressive or oncogenic roles in various carcinomas. This study assesses chemoresistant PDAC for its specific miR expression pattern. Gemcitabine-resistant variants of PANC-1, a mutant p53 human pancreatic adenocarcinoma cell line, were established. MicroRNA screening was investigated by microarray. Gemcitabine-resistant PANC-1 (PANC-1-GR) cell clones were produced by exposing the parental cells to repeated pulsatile gemcitabine treatment over 3 days with constant sublethal concentrations followed by recovery-periods with agent-free medium until the cells recovered exponentially. Parental PANC-1 cells were treated with 0.4µM gemcitabine cycles for approximately 9 months. Affymetrix GeneChip miRNA microarrays (Affymetrix UK Ltd., High Wycombe, UK) were performed in parental and chemoresistant PANC-1 cells after 17 chemotherapy cycles using the manufacturers´ protocols. The samples were prepared from 1µg of total-RNA in accordance with the Affymetrix FlashTag Biotin HSR RNA Labeling Kit. The targets were hybridized overnight to Affymetrix GeneChip miRNA arrays. Following hybridization, the arrays were washed and stained using the Affymetrix GeneChip Fluidics Station 450 and scanned using the Affymetrix GeneChip Scanner 3000 7G. Microarray data quality was checked as recommended by the manufacturer and by the quality metrics in the Partek Genomics Suite software (Partek Inc., St. Louis, MO).
Project description:Purpose: Chemotherapy is pivotal in the multimodal treatment of pancreatic cancer patients. In recent years, technical advances have developed experimental methods that unveiled a high degree of inter- and intratumoral heterogeneity in pancreatic cancer. We hypothesized that intratumoral heterogeneity (ITH) impacts response to gemcitabine treatment and demands specific targeting of resistant subclones. Results: Individual SCDCLs of the parental tumor cell populations of BxPC3 and Panc-1 showed considerable heterogeneity in response to gemcitabine. Unsupervised principal component analysis (PCA) including the 1,000 most variably expressed genes showed a clustering of the SCDCLs according to their respective sensitivity to gemcitabine treatment for BxPC3, while this clustering was less clear for Panc-1. In BxPC3 SCDCLs, enriched signaling pathways EMT, TNF signaling via NfKB, and IL2STAT5 signaling correlated with more resistant behavior to gemcitabine. In Panc-1 SCDCLs MYC targets V1 and V2 as well as E2F targets were associated with stronger resistance to gemcitabine. Feature extraction of proteomes again identified less proteins whose expression was associated with the response of individual SCDCLs in Panc-1 compared to BxPC3. Based on molecular profiles, we could show that the gemcitabine-resistant SCDCLs of both BxPC3 and Panc-1 are more sensitive to the BET inhibitor JQ1 compared to the respective gemcitabine-sensitive SCDCLs. Conclusions: Our model system of SCDCLs identified gemcitabine-resistant subclones within a parental tumor population and provides evidence for the critical role of ITH for treatment response in pancreatic cancer. Through molecular profiling, we identified specific signaling pathways and protein signatures that might help to explain the differential response to treatment among clones. We exploited these molecular differences for an improved and more targeted therapy of resistant subclones of a heterogeneous tumor.
Project description:We examined the microarray-based expression profiles of the cells to identify genes associated with gemcitabine resistance Using a set of parental and gemcitabine resistant cell line, MKN28 and RMKN28, we studied mRNA transcription levels by microarray analysis to see if there are any of the key molecules for development of acquisition of the GEM resistance.
Project description:We examined the microarray-based expression profiles of the cells to identify genes associated with gemcitabine resistance Using three set of parental and resistant cell lines, PK-9 and RPK-9, PK-1 and RPK-1, and PK-59 and RPK-59, we studied mRNA transcription levels by microarray analysis to see if there are any of the key molecules for development of acquisition of the GEM resistance.