0000000000867427
AUTHOR
Roland M Schmid
Resistance-associated substitutions in patients with chronic hepatitis C virus genotype 4 infection
Data on the prevalence of resistance-associated substitutions (RASs) and their implications for treatment with direct-acting antivirals (DAAs) are sparse in European patients with HCV genotype 4. This study investigated RASs before and after DAA failure in different genotype 4 subtypes and evaluated retreatment efficacies. Samples of 195 genotype 4-infected patients were collected in the European Resistance Database and investigated for NS3, NS5A and NS5B RASs. Retreatment efficacies in DAA failure patients were analysed retrospectively. After NS5A inhibitor (NS5Ai) failure, subtype 4r was frequent (30%) compared to DAA-naive patients (5%) and the number of NS5A RASs was significantly highe…
MTOR inhibitor-based combination therapies for pancreatic cancer
Background: Although the mechanistic target of rapamycin (MTOR) kinase, included in the mTORC1 and mTORC2 signalling hubs, has been demonstrated to be active in a significant fraction of patients with pancreatic ductal adenocarcinoma (PDAC), the value of the kinase as a therapeutic target needs further clarification. Methods: We used Mtor floxed mice to analyse the function of the kinase in context of the pancreas at the genetic level. Using a dual-recombinase system, which is based on the flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies, we generated a novel cellular model, allowing the genetic analysis of MTOR functions in tumour maintenance. Cross-species validation and pha…
HDAC1 and HDAC2 integrate the expression of p53 mutants in pancreatic cancer.
Mutation of p53 is a frequent genetic lesion in pancreatic cancer being an unmet clinical challenge. Mutants of p53 have lost the tumour-suppressive functions of wild type p53. In addition, p53 mutants exert tumour-promoting functions, qualifying them as important therapeutic targets. Here, we show that the class I histone deacetylases HDAC1 and HDAC2 contribute to maintain the expression of p53 mutants in human and genetically defined murine pancreatic cancer cells. Our data reveal that the inhibition of these HDACs with small molecule HDAC inhibitors (HDACi), as well as the specific genetic elimination of HDAC1 and HDAC2, reduce the expression of mutant p53 mRNA and protein levels. We fur…
MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib
The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both pr…