Project description:Tumor heterogeneity and resistance to chemotherapy represents a significant challenge in the clinical management of triple negative breast cancer (TNBC). By dissecting molecular pathways associated with treatment resistance, we sought to define patient sub-groups and define actionable targets for next-line treatment. Bulk RNA sequencing were performed on isogenic patient-derived xenografts (PDX) representing paclitaxel-sensitive and -resistant tumors. Pathways identified as upregulated in the resistant model were further explored as targets in downstream approcaches, and their clinical relevance evaluated in publicly available clincial data.
Project description:In this study, we aimed to investigate the gene expression changes associated with the development of paclitaxel resistance in patient-derived xenograft (PDX) models. We established paclitaxel-resistant PDX models in mice by administering 10 mg/kg of paclitaxel via intraperitoneal injection once a week. The treatment continued until the sixth generation of the PDX models was successfully established. RNA sequencing was performed on samples from the first generation (control and treated groups) and the sixth generation (control and treated groups) to identify differentially expressed genes and pathways involved in drug resistance. Our findings provide insights into the molecular mechanisms underlying paclitaxel resistance and may inform the development of more effective therapeutic strategies.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited and very often, ineffective medical and surgical therapeutic options. The treatment of patients with advanced unresectable PDAC is restricted to systemic chemotherapy, a therapeutic intervention to which most eventually develop resistance. Recently, nab-paclitaxel has been added to the arsenal of first line therapies, and the combination of gemcitabine and nab-paclitaxel has modestly prolonged median overall survival. However, patients almost invariably succumb to the disease, and little is known about the mechanisms underlying nab-paclitaxel (n-PTX) resistance. Using the conditionally reprogrammed (CR) cell approach, we established and verified continuously growing cell cultures from treatment-naive PDAC patients. To study the mechanisms of primary drug resistance, nab-paclitaxel-resistant (n-PTX-R) cells were generated from primary cultures and drug resistance was verified in vivo, both in zebrafish and in athymic nude mouse xenograft models. Molecular analyses identified the sustained induction of c-MYC in the nab-paclitaxel-resistant cells. Depletion of c-Myc restored nab-paclitaxel sensitivity, as did treatment with either the MEK inhibitor, trametinib, or a small molecule activator of protein phosphatase 2a (SMAP). Implications: The strategies we have devised, including the patient-derived primary cells and the unique drug resistant isogenic cells, are rapid and easily applied in vitro and in vivo platforms to better understand the mechanisms of drug resistance and for defining effective therapeutic options on a patient by patient basis
Project description:The microtubule-stabilising drug paclitaxel has activity in relapsed ovarian cancer. However, resistance frequently develops. Oncolytic adenoviruses are a novel cancer therapy, and replicate selectively within and lyse malignant cells, leading to productive infection of neighbouring cells. We found increased efficacy of adenoviruses of multiple subtypes in paclitaxel-resistant ovarian cancer cells. There was increased expression of a key adenovirus receptor, CAR (coxsackie adenovirus receptor), due to increased transcription that resulted from histone modification. Moreover, CAR transcription increased in intraperitoneal xenografts with acquired paclitaxel resistance and in tumours from patients with paclitaxel-resistant ovarian cancer. Finally, we identified dysregulated cell cycle control as a second mechanism of increased adenovirus efficacy in paclitaxel-resistant ovarian cancer and that inhibition of CDK4/6 using PD-0332991 was able both to reverse paclitaxel resistance and reduce adenovirus efficacy. Thus, paclitaxel resistance increases oncolytic adenovirus efficacy via at least two separate mechanisms. Parental SKOV3 and paclitaxel-resistant SKOV3-TR cells were analysed in duplicate
Project description:Conventional frontline treatment for ovarian cancer consists of successive chemotherapy cycles of paclitaxel and platinum. Despite the initial favorable responses for most patients, chemotherapy resistance frequently leads to recurrent or refractory disease. New treatment strategies that circumvent or prevent mechanisms of resistance are needed to improve ovarian cancer therapy. We developed in vitro ovarian cancer cell line models of acquired paclitaxel resistance using 2 immortalized human ovarian cancer cell lines, OVCAR3 and TOV-21G. We also developed in vitro primary ovarian cancer organoid models using tumor tissue from 7 patients with gynecologic malignancies. Gene expression differences in resistant and sensitive lines were analyzed by RNA sequencing to identify potential mechanisms of paclitaxel resistance in primary ovarian cancer.
Project description:Paclitaxel is a first-line drug for treating epithelial ovarian cancer (EOC). However, prognosis for patients with advanced stage cancer remains poor due to primary or acquired drug resistance. Therefore, overcoming chemoresistance is one of the greatest challenges in treating EOC. In this study, we identified microRNAs (miRNA) that regulate paclitaxel resistance and tested their potential utility as therapeutic targets. Paclitaxel-resistant cell lines were established using two EOC cell lines: SKVO3ip1 and HeyA8. miRNA PCR arrays showed that miR-194-5p was downregulated in paclitaxel-resistant cells. Forced expression of miR-194-5p resensitized resistant cells to paclitaxel. Conversely, miR-194-5p inhibition induced paclitaxel resistance in parental cells. In silico analysis and luciferase reporter assay revealed that MDM2 is a direct target of miR-194-5p. MDM2 was upregulated in paclitaxel resistant cells compared with parental cells. MDM2 inhibition also resensitized resistant cells to paclitaxel and forced MDM2 induced paclitaxel resistance in parental cells. miR-194-5p induced p21 upregulation and G1 phase arrest in resistant cells by downregulating MDM2. Furthermore, a public database showed that high MDM2 expression was associated with a shorter progression-free survival in EOC patients treated with paclitaxel. Collectively, our results show that restoring miR-194-5p expression resensitizes EOCs to paclitaxel, and this may be exploited as a therapeutic option.
Project description:The microtubule-stabilising drug paclitaxel has activity in relapsed ovarian cancer. However, resistance frequently develops. Oncolytic adenoviruses are a novel cancer therapy, and replicate selectively within and lyse malignant cells, leading to productive infection of neighbouring cells. We found increased efficacy of adenoviruses of multiple subtypes in paclitaxel-resistant ovarian cancer cells. There was increased expression of a key adenovirus receptor, CAR (coxsackie adenovirus receptor), due to increased transcription that resulted from histone modification. Moreover, CAR transcription increased in intraperitoneal xenografts with acquired paclitaxel resistance and in tumours from patients with paclitaxel-resistant ovarian cancer. Finally, we identified dysregulated cell cycle control as a second mechanism of increased adenovirus efficacy in paclitaxel-resistant ovarian cancer and that inhibition of CDK4/6 using PD-0332991 was able both to reverse paclitaxel resistance and reduce adenovirus efficacy. Thus, paclitaxel resistance increases oncolytic adenovirus efficacy via at least two separate mechanisms.
Project description:Resistance to chemotherapy is one of the main causes of mortality in late-stage nasopharyngeal carcinoma (NPC) with dismal prognosis and limited therapeutic options. Therefore, there is an urgent need to exploit new therapeutic targets to improve current clinical outcome. In this study, we identified pacritinib, a late stage clinical drug targeting IRAK1, as a sensitizer to resistance of paclitaxel in NPC. Through analysis of both chemoresistant cellular models and clinical samples of relapse and metastasis, we have shown that aberrant IRAK1-S100A9 deregulation is correlated with chemoresistance and prognosticates poor clinical outcome. Further functional studies demonstrated that genetic and pharmacological inhibition of IRAK1-S100A9 axis overcomes the resistance to paclitaxel and combination of pacritinib with paclitaxel exhibited superior anti-tumor effect in both in vivo and in vitro models.
Project description:To investigate the gene targets associated with paclitaxel resistance in EOC, we cultured A2780 and paclitaxel resistant A2780 (A2780-Taxol) cell lines.