LHBs can elevate the expression of MDR1 through HIF-1α in patients with CHB infection: a comparative proteomic study

Chromosome hyperploidy induced by chronic hepatitis B virus infection and its targeted therapeutic strategy

Chronic hepatitis B virus (HBV) infection induces chromosomal hyperploidy (including aneuploidy and polyploidy) and chromosomal instability in hepatocytes, which is one of the main causes of primary hepatocellular carcinoma (HCC). Although hepatocytes can regulate polyploidization of chromosomes under normal conditions, it is difficult to regulate hyperploidization caused by HBV infection and thus carcinogenesis. Studies have shown that HBV can cause dysregulation of many signal pathways such as PLK1/PRC1, and induce chromosome hyperploidy and malignant transformation of hepatocytes. Herein we review the mechanism of HBV infection-induced chromosomal hyperploidy of hepatocytes to cuase hepatocarcinogenesis and the advances in research of drugs targeting chromosomal hyperploidy.

Overcoming the therapeutic resistance of hepatomas by targeting the tumor microenvironment

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers and is the third leading cause of cancer-related mortality worldwide. Multifactorial drug resistance is regarded as the major cause of treatment failure in HCC. Accumulating evidence shows that the constituents of the tumor microenvironment (TME), including cancer-associated fibroblasts, tumor vasculature, immune cells, physical factors, cytokines, and exosomes may explain the therapeutic resistance mechanisms in HCC. In recent years, anti-angiogenic drugs and immune checkpoint inhibitors have shown satisfactory results in HCC patients. However, due to enhanced communication between the tumor and TME, the effect of heterogeneity of the microenvironment on therapeutic resistance is particularly complicated, which suggests a more challenging research direction. In addition, it has been reported that the three-dimensional (3D) organoid model derived from patient biopsies is more intuitive to fully understand the role of the TME in acquired resistance. Therefore, in this review, we have focused not only on the mechanisms and targets of therapeutic resistance related to the contents of the TME in HCC but also provide a comprehensive description of 3D models and how they contribute to the exploration of HCC therapies.

Mechanisms of P-Glycoprotein Regulation Under Exogenous and Endogenous Oxidative Stress <i>In Vitro</i>

We investigated the mechanisms of P-glycoprotein (P-gp) transporter regulation in Caco-2 cells under exogenous and endogenous oxidative stress (OS). Exogenous OS was modeled by exposure of the growth medium to hydrogen peroxide at concentrations of 0.1, 0.5, and 1 M for 24 h or 10 M for 72 h. Endogenous OS was modeled by incubating cells with DL-buthionine sulfoximine (BSO, gamma-glutamylcysteine synthetase inhibitor) at a concentration of 10, 50, and 100 M for 24 h. The levels of intracellular reactive oxygen species (ROS) were assessed using MitoTracker Red CM-H2XRos fluorescent probes. Relative P-gp contents were analyzed using Western blot. Exogenous and endogenous OS was shown to increase relative to P-gp contents. An important role played by the Nrf2-Keap1 signaling pathway in increasing the P-gp contents under H2O2-induced exogenous OS was revealed using specific inhibitors. The transcription factor HIF1 is involved in the regulation of the P-gp levels under 24-hour exogenous OS, and the transcription factor CAR is involved in the regulation of transporter levels under 72-hour OS. All tested transcription factors and signaling pathways are involved in P-gp induction under endogenous OS. Most likely, this is associated with the bimodal effect of BSO on Pgp. On the one hand, BSO induces the development of OS; on the other, BSO, as a xenobiotic, is able to stimulate PXR and CAR, which, in turn, increase the P-gp contents.

ABCB1 protects bat cells from DNA damage induced by genotoxic compounds

Bats are unusual mammals, with the ability to fly, and long lifespans. In addition, bats have a low incidence of cancer, but the mechanisms underlying this phenomenon remain elusive. Here we discovered that bat cells are more resistant than human and mouse cells to DNA damage induced by genotoxic drugs. We found that bat cells accumulate less chemical than human and mouse cells, and efficient drug efflux mediated by the ABC transporter ABCB1 underlies this improved response to genotoxic reagents. Inhibition of ABCB1 triggers an accumulation of doxorubicin, DNA damage, and cell death. ABCB1 is expressed at higher levels in several cell lines and tissues derived from bats compared to humans. Furthermore, increased drug efflux and high expression of ABCB1 are conserved across multiple bat species. Our findings suggest that enhanced efflux protects bat cells from DNA damage induced by genotoxic compounds, which may contribute to their low cancer incidence.