3-(2-4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3h)-quinazolinone and Carcinoma--Hepatocellular

Pseudolaric acid B (PAB), a natural product isolated from the root bark of Pseudolarix kaempferi, has been reported to exert inhibitory effects in various cancers. However, the underlying mechanisms remain largely unclear. In the present study, we investigated the mechanism through which PAB exert its anticancer effects in hepatocellular carcinoma (HCC). PAB inhibited the viability of and induced apoptosis in Hepa1-6 cells in a dose-dependent manner. It disrupted mitochondrial membrane potential (MMP) and impaired ATP production. Furthermore, PAB induced phosphorylation of DRP1 at Ser616 and mitochondrial fission. Blocking DRP1 phosphorylation by Mdivi-1 inhibited mitochondrial fission and PAB-induced apoptosis. Moreover, c-Jun N-terminal kinase (JNK) was activated by PAB, and blocking JNK activity using SP600125 inhibited PAB-induced mitochondrial fission and cell apoptosis. Furthermore, PAB activated AMP-activated protein kinase (AMPK), and inhibiting AMPK by compound C attenuated PAB-stimulated JNK activation and blocked DRP1-dependent mitochondrial fission and apoptosis. Our in vivo data confirmed that PAB inhibited tumor growth and induced apoptosis in an HCC syngeneic mouse model by inducing the AMPK/JNK/DRP1/mitochondrial fission signaling pathway. Furthermore, a combination of PAB and sorafenib showed a synergistic effect in inhibiting tumor growth in vivo. Taken together, our findings highlight a potential therapeutic strategy for HCC.

Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Carcinoma, Hepatocellular; Dynamins; Liver Neoplasms; Mice; Mice, Inbred Strains; Mitochondrial Dynamics

The efficacy of chemotherapy for hepatocellular carcinoma (HCC) remains unsatisfactory, primarily due to inherent self‑defense mechanisms (e.g., mitophagy and autophagy). In the present study, we aimed to explore the pro‑apoptotic effects of targeting mitophagy to potentiate the efficacy of chemotherapy for HCC. HCC cells were subjected to cisplatin, after which cisplatin‑induced mitophagy was quantified by immunofluorescence. Mdivi‑1, a specific dynamin‑related protein 1 (DRP1) inhibitor, was used to study the role of DRP1 in cisplatin‑induced HCC mitophagy. The synergistic effect of cisplatin and the DRP1 inhibitor on HCC was assessed in vitro and in vivo. Accordingly, cisplatin induced mitophagy in surviving HCC cells by activating DRP1. The DRP1 inhibitor (Mdivi‑1) increased the apoptosis of cisplatin‑treated HCC cells by targeting mitophagy. Mechanistically, Mdivi‑1 upregulated Bax and downregulated Bcl‑xL, leading to an increase in mitochondrial membrane permeability and subsequent release of cytochrome c from mitochondria into the cytosol, thereby aggravating cisplatin‑induced apoptosis in HCC cells. Moreover, Mdivi‑1 acted synergistically with cisplatin to suppress HCC xenograft growth in vivo. Our results indicate that targeting cisplatin‑mediated mitophagy increases HCC apoptosis via DRP1 inhibition, providing preclinical proof of concept for combination therapy targeting mitophagy to potentiate the efficacy of chemotherapy.

Topics: Animals; Apoptosis; Autophagy; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dynamins; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; Mice; Mitochondria; Mitophagy; Quinazolinones; Reactive Oxygen Species; Xenograft Model Antitumor Assays

Cancer stem cells (CSCs) are considered to be the main cause of tumor recurrence, metastasis, and an unfavorable prognosis. Energy metabolism is closely associated with cell stemness. However, how the stemness of liver cancer stem cells (LCSCs) is regulated by metabolic/oxidative stress remains poorly understood. In this study, we compare the metabolic differences between LCSCs and the hepatocellular carcinoma cell line HCCLM3, and explore the relationship between metabolism and LCSC stemness. We found that LCSCs from the hepatocellular carcinoma cell HCCLM3 exhibited more robust glucose metabolism than HCCLM3, including glycolysis, oxidative phosphorylation (OXPHOS), and pyruvate produced by glycolysis entering mitochondria for OXPHOS. Moreover, 2-deoxy-D-glucose (2-DG) enhanced the LCSC stemness by upregulating OXPHOS. In contrast, Mdivi-1 reduced the levels of OXPHOS and weakened the stemness by inhibiting mitochondrial fission. Together, our findings clarify the relationship between energy metabolism and LCSC stemness and may provide theoretical guidance and potential therapeutic approaches for liver cancer.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Humans; Liver Neoplasms; Mitochondria, Liver; Neoplastic Stem Cells; Oxidative Phosphorylation; Quinazolinones

Mitochondrial morphology is dynamically remodeled by fusion and fission in cells, and dysregulation of this process is closely implicated in tumorigenesis. However, the mechanism by which mitochondrial dynamics influence cancer cell survival is considerably less clear, especially in hepatocellular carcinoma (HCC). In this study, we systematically investigated the alteration of mitochondrial dynamics and its functional role in the regulation of autophagy and HCC cell survival. Furthermore, the underlying molecular mechanisms and therapeutic application were explored in depth. Mitochondrial fission was frequently upregulated in HCC tissues mainly due to an elevated expression ratio of DNM1L to MFN1, which significantly contributed to poor prognosis of HCC patients. Increased mitochondrial fission by forced expression of DNM1L or knockdown of MFN1 promoted the survival of HCC cells both in vitro and in vivo mainly by facilitating autophagy and inhibiting mitochondria-dependent apoptosis. We further demonstrated that the survival-promoting role of increased mitochondrial fission was mediated via elevated ROS production and subsequent activation of AKT, which facilitated MDM2-mediated TP53 degradation, and NFKBIA- and IKK-mediated transcriptional activity of NFKB in HCC cells. Also, a crosstalk between TP53 and NFKB pathways was involved in the regulation of mitochondrial fission-mediated cell survival. Moreover, treatment with mitochondrial division inhibitor-1 significantly suppressed tumor growth in an in vivo xenograft nude mice model. Our findings demonstrate that increased mitochondrial fission plays a critical role in regulation of HCC cell survival, which provides a strong evidence for this process as drug target in HCC treatment.

Topics: Animals; Apoptosis; Autophagy; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dynamins; Female; Gene Expression Regulation, Neoplastic; GTP Phosphohydrolases; Humans; Liver Neoplasms; Male; Mice; Mice, Inbred C57BL; Mice, Nude; Microtubule-Associated Proteins; Middle Aged; Mitochondrial Dynamics; Mitochondrial Proteins; NF-kappa B; Prognosis; Quinazolinones; Reactive Oxygen Species; Signal Transduction; Tumor Suppressor Protein p53; Up-Regulation