Rat B Cell Leukemia X long ELISA Kit

Anti-apoptotic Bcl-2-family members are frequently dysregulated in both blood and solid cancers, contributing to their survival despite ongoing oncogenic stress. Yet, such cancer cells often are highly dependent on Bcl-2 for their survival, a feature that is exploited by so-called BH3-mimetic drugs. Venetoclax (ABT-199) is a selective BH3-mimetic Bcl-2 antagonist that is currently used in the clinic for treatment of chronic lymphocytic leukemia patients. Unfortunately, venetoclax resistance has already emerged in patients, limiting the therapeutic success. Here, we examined strategies to overcome venetoclax resistance. Therefore, we used two diffuse large B-cell lymphoma (DLBCL) cell lines, Riva WT and venetoclax-resistant Riva (VR). The latter was obtained by prolonged culturing in the presence of venetoclax. We report that Riva VR cells did not become more sensitive to BIRD-2, a peptide targeting the Bcl-2 BH4 domain, and established cross-resistance towards BDA-366, a putative BH4-domain antagonist of Bcl-2. However, we found that Bcl-XL, another Bcl-2-family protein, is upregulated in Riva VR, while Mcl-1 expression levels are not different in comparison with Riva WT, hinting towards an increased dependence of Riva VR cells to Bcl-XL. Indeed, Riva VR cells could be resensitized to venetoclax by A-1155463, a selective BH3 mimetic Bcl-XL inhibitor. This is underpinned by siRNA experiments, demonstrating that lowering Bcl-XL-expression levels also augmented the sensitivity of Riva VR cells to venetoclax. Overall, this work demonstrates that Bcl-XL upregulation contributes to acquired resistance of DLBCL cancer cells towards venetoclax and that antagonizing Bcl-XL can resensitize such cells towards venetoclax.

Liver cancer or hepatocellular carcinoma is considered to be the third leading cause of death among all other cancers. The rate of liver cancer occurrence is high, and the rate of recovery is low. In this study, we investigated the therapeutic efficacy of vicenin-2 against the diethylnitrosamine-induced liver carcinoma in experimental rats. Diethylnitrosamine was widely employed as a carcinogenic agent to stimulate the cancer in animal models. Our results indicated that vicenin-2 administration effectively attenuates the diethylnitrosamine-induced physiological and pharmacological alterations in the experimental rats. Vicenin-2 treatment significantly enhanced the pathological lesions and decreased the levels of alaninc aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alpha-fetoprotein (AFP) in serum. We also observed that vicenin-2 reduced the production of reactive oxygen species, decreased the liver weight, upregulated expression of apoptotic proteins, and decreased the histological changes in the liver, which are induced by the diethylnitrosamine in rats. Moreover, vicenin-2 downregulates antiapoptotic Bcl-2 and Bcl-xL, and upregulates the proapoptotic Bax and caspase. Hence, our results suggested that vicenin-2 had a highly therapeutic effect in reversing diethylnitrosamine-induced liver carcinoma in rats, which might be related to the apoptosis induced by vicenin-2. Therefore vicenin-2 could be a good candidate for future therapeutic use to inhibit chemically induced liver cancer.