PLEKHG5 is stabilized by HDAC2-related deacetylation and confers sorafenib resistance in hepatocellular carcinoma

Diesel exhaust promoted diethylnitrosamine-induced hepatocarcinogenesis in mice

Exposure to diesel exhaust (DE) has been linked to an increased risk of various cancers, including liver cancer. However, the underlying mechanisms driving this association remain insufficiently understood. In this study, we employed a diethylnitrosamine (DEN)-induced mouse liver tumor model and conducted a 19-week combined exposure (750 μg/m3) using a DE exposure system. Our results demonstrated that long-term DE exposure activates cancer-related genes and enhances the formation of DEN-induced liver tumors. Compared to the DEN group, mice in the DEN + diesel exhaust exposure (DEE) group exhibited lower body weight, higher tumor formation rates and more severe DNA damage. The tumor-promoting effect of DE may be associated with the upregulation of SEMA4D and the activation of the PI3K/AKT signaling pathway. Additionally, liver cells in the DEE group exhibited nuclear atypia, a characteristic feature of cancerous transformation. In vitro studies have revealed that exposure to diesel exhaust particles (DEP) promotes the proliferation of HepG2 cells and HUH7 cells by upregulating SEMA4D and activating the PI3K/AKT signaling pathway. This effect was attenuated by inhibiting either SEMA4D or PI3K. This study was the first to identify that DE exposure promotes the development of DEN-induced liver tumors in mice, with the mechanism potentially involving the SEMA4D/PI3K/AKT pathway. These findings provide novel insights into the hepatotoxic effects of DE and highlight the need for further investigation into its carcinogenic potential.

Acetylation and deacetylation dynamics in stress response to cancer and infections

In response to stress stimuli, cells have evolved various mechanisms to integrate internal and external signals to achieve dynamic homeostasis. Lysine acetyltransferase (KATs) and deacetyltransferase (KDACs) are the key modulators of epigenetic modifications, enabling cells to modulate cellular responses through the acetylation and deacetylation of both histone and nonhistone proteins. Understanding the signaling pathways involved in cellular stress response, along with the roles of KATs and KDACs may pave the way for the development of novel therapeutic strategies. This review discusses the molecular mechanisms of acetylation and deacetylation in stress responses related to tumorigenesis, viral and bacterial infections. In tumorigenesis section, we focused on the tumor cells' intrinsic and external molecules and signaling pathways regulated by acetylation and deacetylation modification. In viral and bacterial infections, we summarized the update research on acetylation and deacetylation modification in viral and bacterial infections, which systematical introduction on this topic is not too much. Additionally, we provide an overview of current therapeutic interventions and clinical trials involving KAT and KDAC inhibitors in the treatment of cancer, as well as viral and bacterial infection-related diseases.

Mechanisms of sorafenib resistance in hepatocellular carcinoma

Liver cancer is one of the most common and devastating causes of cancer-related deaths worldwide. Hepatocellular carcinoma (HCC) accounts for approximately 90% of primary liver cancers and represents a significant global health issue. There is currently no effective systemic treatment for patients with advanced liver cancer. One study suggests that sorafenib may be effective against hepatocellular carcinoma. Sorafenib can significantly extend the median survival time of patients, but only by 3-5 months. Furthermore, it is linked to severe adverse side effects and frequently leads to drug resistance. In this review, we offer a critical analysis of the factors contributing to sorafenib resistance in HCC.

HDAC2 promotes autophagy-associated HCC malignant progression by transcriptionally activating LAPTM4B

Hepatocellular carcinoma (HCC) is a significant global health challenge. The activation of autophagy plays an essential role in promoting the proliferation and survival of cancer cells. However, the upstream regulatory network and mechanisms governing autophagy in HCC remain unclear. This study demonstrated that histone deacetylase 2 (HDAC2) regulates autophagy in HCC. Its expression was elevated in HCC tissues, and high HDAC2 expression was strongly associated with poor prognosis in individuals with HCC. Integrated in vitro and in vivo investigations confirmed that HDAC2 promotes autophagy and autophagy-related malignant progression in HCC. Mechanistically, HDAC2 bound specifically to the lysosome-associated protein transmembrane 4-β (LAPTM4B) promoter at four distinct binding sites, enhancing its transcriptional activation and driving autophagy-related malignant progression in HCC. These findings establish LAPTM4B as a direct target gene of HDAC2. Furthermore, the selective inhibitor of HDAC2 effectively alleviated the malignant development of HCC. In addition, multivariate Cox regression analysis of 105 human HCC samples revealed that HDAC2 expression is an independent predictor of HCC prognosis. This study underscores the crucial role of the HDAC2-LAPTM4B axis in regulating autophagy in the malignant evolution of HCC and highlights the potential of targeting HDAC2 to prevent and halt the malignant progression of HCC.

Advances in hepatocellular carcinoma drug resistance models

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Surgery has been the major treatment method for HCC owing to HCC's poor sensitivity to radiotherapy and chemotherapy. However, its effectiveness is limited by postoperative tumour recurrence and metastasis. Systemic therapy is applied to eliminate postoperative residual tumour cells and improve the survival of patients with advanced HCC. Recently, the emergence of various novel targeted and immunotherapeutic drugs has significantly improved the prognosis of advanced HCC. However, targeted and immunological therapies may not always produce complete and long-lasting anti-tumour responses because of tumour heterogeneity and drug resistance. Traditional and patient-derived cell lines or animal models are used to investigate the drug resistance mechanisms of HCC and identify drugs that could reverse the resistance. This study comprehensively reviewed the established methods and applications of in-vivo and in-vitro HCC drug resistance models to further understand the resistance mechanisms in HCC treatment and provide a model basis for possible individualised therapy.

Dual-molecular targeting nanomedicine upregulates synergistic therapeutic efficacy in preclinical hepatoma models

Advanced hepatocellular carcinoma (HCC) is one of the most challenging cancers because of its heterogeneous and aggressive nature, precluding the use of curative treatments. Sorafenib (SOR) is the first approved molecular targeting agent against the mitogen-activated protein kinase (MAPK) pathway for the noncurative therapy of advanced HCC; yet, any clinically meaningful benefits from the treatment remain modest, and are accompanied by significant side effects. Here, we hypothesized that using a nanomedicine platform to co-deliver SOR with another molecular targeting drug, metformin (MET), could tackle these issues. A micelle self-assembled with amphiphilic polypeptide methoxy poly(ethylene glycol)-block-poly(L-phenylalanine-co-l-glutamic acid) (mPEG-b-P(LP-co-LG)) (PM) was therefore designed for combinational delivery of two molecular targeted drugs, SOR and MET, to hepatomas. Compared with free drugs, the proposed, dual drug-loaded micelle (PM/SOR+MET) enhanced the drugs' half-life in the bloodstream and drug accumulation at the tumor site, thereby inhibiting tumor growth effectively in the preclinical subcutaneous, orthotopic and patient-derived xenograft hepatoma models without causing significant systemic and organ toxicity. Collectively, these findings demonstrate an effective dual-targeting nanomedicine strategy for treating advanced HCC, which may have a translational potential for cancer therapeutics. STATEMENT OF SIGNIFICANCE: Treatment of advanced hepatocellular carcinoma (HCC) remains a formidable challenge due to its aggressive nature and the limitations inherent to current therapies. Despite advancements in molecular targeted therapies, such as Sorafenib (SOR), their modest clinical benefits coupled with significant adverse effects underscore the urgent need for more efficacious and less toxic treatment modalities. Our research presents a new nanomedicine platform that synergistically combines SOR with metformin within a specialized diblock polypeptide micelle, aiming to enhance therapeutic efficacy while reducing systemic toxicity. This innovative approach not only exhibits marked antitumor efficacy across multiple HCC models but also significantly reduces the toxicity associated with current treatments. Our dual-molecular targeting approach unveils a promising nanomedicine strategy for the molecular treatment of advanced HCC, potentially offering more effective and safer treatment alternatives with significant translational potential.

NFKBIZ regulates NFκB signaling pathway to mediate tumorigenesis and metastasis of hepatocellular carcinoma by direct interaction with TRIM16

Hepatocellular carcinoma (HCC) is a malignant tumor with high incidence and mortality rates. NFKBIZ, a member of the nuclear factor kappa B inhibitory family, is closely related to tumor progression. However, the precise role of NFKBIZ in HCC remains unclear. To explore this, we conducted a series of experiments from clinic to cells. Western blot and qPCR revealed a significant downregulation of NFKBIZ in human HCC tissues. Clinical character analysis showed that the patients with lower NFKBIZ expression had poorer prognosis and higher clinical stage. By using CCK-8, wound healing, transwell invasion and migration assay, we discovered that NFKBIZ expression was reversely associated with the proliferation, invasion, and migration ability of HCC cells in vitro. Additionally, the results obtained from xenograft assay and lung metastasis models showed that NFKBIZ overexpression inhibited the growth and metastasis of HCC cells in vivo. Western blot and immunofluorescence assay further revealed that NFKBIZ mediated HCC cell growth and migration by regulating NFκB signaling transduction. Finally, flow cytometry, protein degradation assay and Co-immunoprecipitation indicated that TRIM16 can enhance NFKBIZ ubiquitination by direct interactions at its K48 site, which may thereby alleviate HCC cell apoptosis to induce the insensitivity to sorafenib. In conclusion, our study demonstrated that NFKBIZ regulated HCC tumorigenesis and metastasis by mediating NFκB signal transduction and TRIM16/NFKBIZ/NFκB axis may be the underlying mechanism of sorafenib insensitivity in HCC.