Dataset Information

In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer.

ABSTRACT: In solid tumors, resistance to therapy inevitably develops upon treatment with cytotoxic drugs or molecularly targeted therapies. Here, we describe a system that enables pooled shRNA screening directly in mouse hepatocellular carcinomas (HCC) in vivo to identify genes likely to be involved in therapy resistance. Using a focused shRNA library targeting genes located within focal genomic amplifications of human HCC, we screened for genes whose inhibition increased the therapeutic efficacy of the multikinase inhibitor sorafenib. Both shRNA-mediated and pharmacological silencing of Mapk14 (p38?) were found to sensitize mouse HCC to sorafenib therapy and prolong survival by abrogating Mapk14-dependent activation of Mek-Erk and Atf2 signaling. Elevated Mapk14-Atf2 signaling predicted poor response to sorafenib therapy in human HCC, and sorafenib resistance of p-Mapk14-expressing HCC cells could be reverted by silencing Mapk14. Our results suggest that a combination of sorafenib and Mapk14 blockade is a promising approach to overcoming therapy resistance of human HCC.

SUBMITTER: Rudalska R

PROVIDER: S-EPMC4587571 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer.

Rudalska Ramona R Dauch Daniel D Longerich Thomas T McJunkin Katherine K Wuestefeld Torsten T Kang Tae-Won TW Hohmeyer Anja A Pesic Marina M Leibold Josef J von Thun Anne A Schirmacher Peter P Zuber Johannes J Weiss Karl-Heinz KH Powers Scott S Powers Scott S Malek Nisar P NP Eilers Martin M Sipos Bence B Lowe Scott W SW Geffers Robert R Laufer Stefan S Zender Lars L

Nature medicine 20140914 10

In solid tumors, resistance to therapy inevitably develops upon treatment with cytotoxic drugs or molecularly targeted therapies. Here, we describe a system that enables pooled shRNA screening directly in mouse hepatocellular carcinomas (HCC) in vivo to identify genes likely to be involved in therapy resistance. Using a focused shRNA library targeting genes located within focal genomic amplifications of human HCC, we screened for genes whose inhibition increased the therapeutic efficacy of the m ...[more]

PMID: 25216638

Similar Datasets

Project description:BackgroundPancreatic cancer retains a poor prognosis among the gastrointestinal cancers. It affects 230,000 individuals worldwide, has a very high mortality rate, and remains one of the most challenging malignancies to treat successfully. Treatment with gemcitabine, the most widely used chemotherapeutic against pancreatic cancer, is not curative and resistance may occur. Combinations of gemcitabine with other chemotherapeutic drugs or biological agents have resulted in limited improvement.MethodsIn order to improve gemcitabine response in pancreatic cancer cells, we utilized a synthetic lethal RNAi screen targeting 572 known kinases to identify genes that when silenced would sensitize pancreatic cancer cells to gemcitabine.ResultsResults from the RNAi screens identified several genes that, when silenced, potentiated the growth inhibitory effects of gemcitabine in pancreatic cancer cells. The greatest potentiation was shown by siRNA targeting checkpoint kinase 1 (CHK1). Validation of the screening results was performed in MIA PaCa-2 and BxPC3 pancreatic cancer cells by examining the dose response of gemcitabine treatment in the presence of either CHK1 or CHK2 siRNA. These results showed a three to ten-fold decrease in the EC50 for CHK1 siRNA-treated cells versus control siRNA-treated cells while treatment with CHK2 siRNA resulted in no change compared to controls. CHK1 was further targeted with specific small molecule inhibitors SB 218078 and PD 407824 in combination with gemcitabine. Results showed that treatment of MIA PaCa-2 cells with either of the CHK1 inhibitors SB 218078 or PD 407824 led to sensitization of the pancreatic cancer cells to gemcitabine.ConclusionThese findings demonstrate the effectiveness of synthetic lethal RNAi screening as a tool for identifying sensitizing targets to chemotherapeutic agents. These results also indicate that CHK1 could serve as a putative therapeutic target for sensitizing pancreatic cancer cells to gemcitabine.

Project description:BackgroundOverexpression of Aurora-A (AURKA) is a feature of breast cancer and associates with adverse prognosis. The selective Aurora-A inhibitor alisertib (MLN8237) has recently demonstrated promising antitumor responses as a single agent in various cancer types but its phase III clinical trial was reported as a failure since MLN8237 did not show an apparent effect in prolonging the survival of patients. Thus, identification of potential targets that could enhance the activity of MLN8237 would provide a rationale for drug combination to achieve better therapeutic outcome.MethodsHere, we conducted a systematic synthetic lethality CRISPR/Cas9 screening of 507 kinases using MLN8237 in breast cancer cells and identified a number of targetable kinases that displayed synthetic lethality interactions with MLN8237. Then, we performed competitive growth assays, colony formation assays, cell viability assays, apoptosis assays, and xenograft murine model to evaluate the synergistic therapeutic effects of Haspin (GSG2) depletion or inhibition with MLN8237. For mechanistic studies, immunofluorescence was used to detect the state of microtubules and the localization of Aurora-B and mitotic centromere-associated kinesin (MCAK).ResultsAmong the hits, we observed that Haspin depletion or inhibition marginally inhibited breast cancer cell growth but could substantially enhance the killing effects of MLN8237. Mechanistic studies showed that co-treatment with Aurora-A and Haspin inhibitors abolished the recruitment of Aurora-B and mitotic centromere-associated kinesin (MCAK) to centromeres which were associated with excessive microtubule depolymerization, kinetochore-microtubule (KT-MT) attachment failure, and severe mitotic catastrophe. We further showed that the combination of MLN8237 and the Haspin inhibitor CHR-6494 synergistically reduced breast cancer cell viability and significantly inhibited both in vitro and in vivo tumor growth.ConclusionsThese findings establish Haspin as a synthetic lethal target and demonstrate CHR-6494 as a potential combinational drug for promoting the therapeutic effects of MLN8237 on breast cancer.

Dataset Information

In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer.

Publications

In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets