SMAC mimetic birinapant inhibits hepatocellular carcinoma growth by activating the cIAP1/TRAF3 signaling pathway

Regulation of apoptosis by ubiquitination in liver cancer

Apoptosis is a programmed cell death process critical to cell development and tissue homeostasis in multicellular organisms. Defective apoptosis is a crucial step in the malignant transformation of cells, including hepatocellular carcinoma (HCC), where the apoptosis rate is higher than in normal liver tissues. Ubiquitination, a post-translational modification process, plays a precise role in regulating the formation and function of different death-signaling complexes, including those involved in apoptosis. Aberrant expression of E3 ubiquitin ligases (E3s) in liver cancer (LC), such as cellular inhibitors of apoptosis proteins (cIAPs), X chromosome-linked IAP (XIAP), and linear ubiquitin chain assembly complex (LUBAC), can contribute to HCC development by promoting cell survival and inhibiting apoptosis. Therefore, the review introduces the main apoptosis pathways and the regulation of proteins in these pathways by E3s and deubiquitinating enzymes (DUBs). It summarizes the abnormal expression of these regulators in HCC and their effects on cancer inhibition or promotion. Understanding the role of ubiquitination in apoptosis and LC can provide insights into potential targets for therapeutic intervention.

Characteristic of molecular subtypes based on PANoptosis-related genes and experimental verification of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a type of liver cancer that originates from liver cells. It is one of the most common types of liver cancer and a leading cause of cancer-related death worldwide. Early detection and treatment can improve the HCC prognosis. Therefore, it is necessary to further improve HCC markers and risk stratification. PANoptosome is a cytoplasmic polymer protein complex that regulates a proinflammatory programmed cell death pathway called "PANoptosis". The role of PANoptosis in HCC remains unclear. In this study, the molecular changes of PANoptosis related genes (PAN-RGs) in HCC were systematically evaluated. We characterized the heterogeneity of HCC by using consensus clustering to identify two distinct subtypes. The two subtypes showed different survival rate, biological function, chemotherapy drug sensitivity and immune microenvironment. After identification of PAN-RG differential expression genes (DEGs), a prognostic model was established by Cox regression analysis using minimum absolute contraction and selection operator (LASSO), and its prognostic value was verified by Cox regression analysis, Kaplan-Meier curve and receiver operating characteristic (ROC) curve. Our own specimens were also used to further validate the prognostic significance and possible clinical value of the selected targets. Subsequently, we conducted a preliminary discussion on the reasons for the influence of the model on the prognosis through TME analysis, drug resistance analysis, TMB analysis and other studies. This study provides a new idea for individualized and precise treatment of HCC.

Ficus dubia Latex Extract Induces Cell Cycle Arrest and Apoptosis by Regulating the NF-κB Pathway in Inflammatory Human Colorectal Cancer Cell Lines

Colorectal cancer is one of the most diagnosed cancers that is associated with inflammation. Ficus dubia latex is recognized as a remedy with various therapeutic effects in traditional medicine, including anti-inflammatory and antioxidant activity. The present study aims to compare the anti-tumor activity of Ficus dubia latex extract (FDLE) against HCT-116 and HT-29 human colorectal cancer cell lines in normal and inflammatory condition and explore its mechanism of action. FDLE exhibited remarkable antiproliferative activity against HCT-116 and HT-29 colorectal cancer cell lines in both conditions using MTT and colony formation assays and more effective anti-proliferation was observed in inflammatory condition. Mechanistically, FDLE induced cell cycle arrest at G0/G1 phase by down-regulating NF-κB, cyclin D1, CDK4 and up-regulatingp21 in both cell in normal condition. In inflammatory condition, FDLE not only exhibited stronger induction of cell cycle arrest in both cells by down-regulating NF-κB, cyclin D1, CDK4 and down-regulating p21, but also selectively induced apoptosis in HCT-116 cells by down-regulating NF-κB and Bcl-xl and up-regulating Bid, Bak, cleaved caspase-7 and caspase-3 through stronger ability to regulate these proteins. Our results demonstrated that the phytochemical agent in the latex of Ficus dubia could potential be used for treatment and prevention of human colorectal cancer, especially in inflammation-induced hyperproliferation progression.

Overview of the progress and prospects of SMAC mimetics in cancers: Is it a silver bullet?

Loss of apoptosis results in the survival and uncontrolled proliferation of cancer cells. Basic and clinical researchers have dissected myriads of central regulators of apoptosis. Second mitochondria-derived activator of caspases (SMAC)/ direct inhibitor of apoptosis protein (IAP)-binding protein with low pI (DIABLO) has attracted phenomenal attention because of its amazing ability to trigger apoptotic death. Accordingly, different teams of interdisciplinary researchers are working on the design and development of SMAC mimetics which can significantly inhibit primary and secondary tumor growth.

Development of a Toll-Like Receptor-Based Gene Signature That Can Predict Prognosis, Tumor Microenvironment, and Chemotherapy Response for Hepatocellular Carcinoma

Objective: Emerging evidence highlights the implications of the toll-like receptor (TLR) signaling pathway in the pathogenesis and therapeutic regimens of hepatocellular carcinoma (HCC). Herein, a prognostic TLR-based gene signature was conducted for HCC.

Methods: HCC-specific TLRs were screened in the TCGA cohort. A LASSO model was constructed based on prognosis-related HCC-specific TLRs. The predictive efficacy, sensitivity, and independency of this signature was then evaluated and externally verified in the ICGC, GSE14520, and GSE76427 cohorts. The associations between this signature and tumor microenvironment (stromal/immune score, immune checkpoint expression, and immune cell infiltrations) and chemotherapy response were assessed in HCC specimens. The expression of TLRs in this signature was verified in HCC and normal liver tissues by Western blot. Following si-MAP2K2 transfection, colony formation and apoptosis of Huh7 and HepG2 cells were examined.

Results: Herein, we identified 60 HCC-specific TLRs. A TLR-based gene signature (MAP2K2, IRAK1, RAC1, TRAF3, MAP3K7, and SPP1) was conducted for HCC prognosis. High-risk patients exhibited undesirable outcomes. ROC curves confirmed the well prediction performance of this signature. Multivariate Cox regression analysis demonstrated that the signature was an independent prognostic indicator. Also, high-risk HCC was characterized by an increased immune score, immune checkpoint expression, and immune cell infiltration. Meanwhile, high-risk patients displayed higher sensitivity to gemcitabine and cisplatin. The dysregulation of TLRs in the signature was confirmed in HCC. MAP2K2 knockdown weakened colony formation and elevated apoptosis of Huh7 and HepG2 cells.

Conclusion: Collectively, this TLR-based gene signature might assist clinicians to select personalized therapy programs for HCC patients.

Combination of Wogonin and Artesunate Exhibits Synergistic anti-Hepatocellular Carcinoma Effect by Increasing DNA-Damage-Inducible Alpha, Tumor Necrosis Factor α and Tumor Necrosis Factor Receptor-Associated Factor 3-mediated Apoptosis

Hepatocellular carcinoma (HCC) is difficult to treat, and is the second leading cause of cancer-related death worldwide. This study aimed to examine whether combination of wogonin and artesunate exhibits synergistic anti-HCC effect. Our data show that the combination treatment exhibits synergistic effect in reducing HCC cell viability by increasing apoptosis as indicated by the elevated cleavage of caspase 8, 3 and PARP. Interestingly, PCR array and the subsequent studies indicate that the combination treatment significantly increases the expression of DNA-damage-inducible, alpha (GADD45A), tumor necrosis factor (TNFα) and TNF receptor-associated factor 3 (TRAF3). Knockdown of GADD45A, TNFα or TRAF3 abolishes the combination treatment-enhanced apoptosis and the synergistic effect in reducing HCC cell viability. In the HCC-bearing xenograft mouse models, although the combination treatment increases the activity of NFκB in the tumor tissues, it exhibits a more potent anti-HCC effect than the mono-treatment, which may due to the enhanced apoptosis as indicated by the increased expression of GADD45A, TNFα, TRAF3 and apoptotic markers. Our study clearly demonstrates that the combination of artesunate and wogonin exhibits synergistic anti-HCC effect, and support the further development of this combination as alternative therapeutics for HCC management.

An Updated Review of Smac Mimetics, LCL161, Birinapant, and GDC-0152 in Cancer Treatment

Inhibitor of apoptosis proteins (IAPs) are suggested as therapeutic targets for cancer treatment. Smac/DIABLO is a natural IAP antagonist in cells; therefore, Smac mimetics have been developed for cancer treatment in the past decade. In this article, we review the anti-cancer potency and novel molecular targets of LCL161, birinapant, and GDC-0152. Preclinical studies demonstrated that Smac mimetics not only induce apoptosis but also arrest cell cycle, induce necroptosis, and induce immune storm in vitro and in vivo. The safety and tolerance of Smac mimetics are evaluated in phase 1 and phase 2 clinical trials. In addition, the combination of Smac mimetics and chemotherapeutic compounds was reported to improve anti-cancer effects. Interestingly, the novel anti-cancer molecular mechanism of action of Smac mimetics was reported in recent studies, suggesting that many unknown functions of Smac mimetics still need to be revealed. Exploring these currently unknown signaling pathways is important to provide hints for the modification and combination therapy of further compounds.