Loss of tumor intrinsic PD-L1 confers resistance to drug-induced apoptosis in human colon cancer.

Loss of tumor intrinsic PD-L1 confers resistance to drug-induced apoptosis in human colon cancer. Neoplasma. 2020 Oct 08;: Authors: Feng D, Chen Z, He X, Huang S, Zhang Z Abstract Colorectal cancer (CRC) with BRAF (V600E) is associated with microsatellite instability (MSI) that predicts response to immune checkpoint inhibitors. We demonstrated the interrogation of TCGA RNA-seq human datasets revealed that BRAFV600E tumors had significantly higher Programmed Death Ligand 1 (PD-L1) mRNA compared to non-mutated BRAF CRCs. Also, MSI-H tumors were evaluated as higher PD-L1 than MSS CRCs. Inhibition of MEK/ERK by cobimetinib or CDK inhibitor dinaciclib was shown to attenuate mutant BRAF-induced PD-L1 coincident with reduced c-JUN and YAP expression whose combined knockdown reduced PD-L1. Using TCGA datasets, PD-L1 mRNA expression in human colon cancers was significantly associated with YAP expression. The deletion of PD-L1 can reduce tumor cell growth shown by clonogenic assay. Analysis of the role of PD-L1 as a mediator of chemosensitivity was then performed. Knockout of PD-L1 was shown to attenuate the induction of DNA double-strand breaks (pH2AX) and caspase-3 cleavage by 5-fluorouracil (5-FU) and paclitaxel compared to parental CRC cells. Results were confirmed in PD-L1 knockout MC38 murine CRC cells where re-expression of wild-type PD-L1 promoted DNA damage and apoptosis. We also performed the clonogenic assay and flow cytometry to prove that loss of PD-L...
Source: Neoplasma - Category: Cancer & Oncology Authors: Tags: Neoplasma Source Type: research

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Source: Frontiers in Pharmacology - Category: Drugs & Pharmacology Source Type: research
Abstract The majority of cancers detected every year are treated with anti-cancer compounds. Unfortunately, many tumors become resistant to antineoplastic drugs. One option is to use cocktails of compounds acting on different targets to try to overcome the resistant cells. This type of approach can produce good results, but is often accompanied by a sharp increase of associated side effects. The strategy presented herein focuses on the use of a single compound acting on two different biological targets enhancing potency and lowering the toxicity of the chemotherapy. In this light, the approach presented in the cur...
Source: Bioorganic Chemistry - Category: Chemistry Authors: Tags: Bioorg Chem Source Type: research
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Source: GEO: Gene Expression Omnibus - Category: Genetics & Stem Cells Tags: Expression profiling by array Mus musculus Source Type: research
Shigeru Okada John J. Kopchick Growth hormone (GH) facilitates therapy resistance in the cancers of breast, colon, endometrium, and melanoma. The GH-stimulated pathways responsible for this resistance were identified as suppression of apoptosis, induction of epithelial-to-mesenchymal transition (EMT), and upregulated drug efflux by increased expression of ATP-binding cassette containing multidrug efflux pumps (ABC-transporters). In extremely drug-resistant melanoma, ABC-transporters have also been reported to mediate drug sequestration in intracellular melanosomes, thereby reducing drug efficacy. Melanocyte-inducing...
Source: Cancers - Category: Cancer & Oncology Authors: Tags: Article Source Type: research
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Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
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Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
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Source: Frontiers in Pharmacology - Category: Drugs & Pharmacology Source Type: research
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Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
In this study, we evaluated the therapeutic benefit of combining the TAB004 antibody with Liposomal-MSA-IL-2 in immune competent and human MUC1 transgenic (MUC1.Tg) mouse models of PDA and investigated the associated immune responses. Treatment with TAB004 + Lip-MSA-IL-2 resulted in significantly improved survival and slower tumor growth compared to controls in MUC1.Tg mice bearing an orthotopic PDA.MUC1 tumor. Similarly, in the spontaneous model of PDA that expresses human MUC1, the combination treatment stalled the progression of pancreatic intraepithelial pre-neoplastic (PanIN) lesion to adenocarcinoma. Treatment with t...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
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