Recent studies suggest that metformin, which is commonly used as an oral anti-hyperglycemic agent of the biguanide family, may reduce cancer risk and improve prognosis, but the mechanisms by which metformin affects various cancers, including gastric cancer, remains unknown. The goal of the present study was to evaluate the effects of metformin on human gastric cancer cell proliferation in vitro and in vivo and to study microRNAs (miRNA) associated with antitumor effect of metformin. We used MKN1, MKN45, and MKN74 human gastric cancer cell lines to study the effects of metformin on human gastric cancer cells. Athymic nude mice bearing xenograft tumors were treated with or without metformin. Tumor growth was recorded after 4 weeks, and the expression of cell-cycle-related proteins was determined. In addition, we used miRNA array tips to explore the differences among miRNAs in MKN74 cells bearing xenograft tumors treated with or without metformin in vitro and in vivo. Metformin inhibited the proliferation of MKN1, MKN45, and MKN74 in vitro. Metformin blocked the cell cycle in G 0 -G 1 in vitro and in vivo. This blockade was accompanied by a strong decrease of G 1 cyclins, especially in cyclin D1, cyclin-dependent kinase (Cdk) 4, Cdk6 and by a decrease in retinoblastoma protein (Rb) phosphorylation. In addition, metformin reduced the phosphorylation of epidermal growth factor receptor and insulin-like growth factor-1 receptor in vitro and in vivo. The miRNA expression was markedly altered with the treatment of metformin in vitro and in vivo. Various miRNAs altered by metformin also may contribute to tumor growth in vitro and in vivo. Mol Cancer Ther; 11(3); 549-60. Ó2012 AACR.

Liver cancer has the fourth highest mortality rate of all cancers worldwide, with hepatocellular carcinoma (HCC) being the most prevalent subtype. Despite great advances in systemic therapy, such as molecular-targeted agents, HCC has one of the worst prognoses due to drug resistance and frequent recurrence and metastasis. Recently, new therapeutic strategies such as cancer immunosuppressive therapy have prolonged patients’ lives, and the combination of an immune checkpoint inhibitor (ICI) and VEGF inhibitor is now positioned as the first-line therapy for advanced HCC. Since the efficacy of ICIs depends on the tumor immune microenvironment, it is necessary to elucidate the immune environment of HCC to select appropriate ICIs. In this review, we summarize the findings on the immune microenvironment and immunosuppressive approaches focused on monoclonal antibodies against cytotoxic T lymphocyte-associated protein 4 and programmed cell death protein 1 for HCC. We also describe ongoing treatment modalities, including adoptive cell transfer-based therapies and future areas of exploration based on recent literature. The results of pre-clinical studies using immunological classification and animal models will contribute to the development of biomarkers that predict the efficacy of immunosuppressive therapy and aid in the selection of appropriate strategies for HCC treatment.

Galectin-9, a soluble β-galactoside-binding animal lectin, evokes apoptosis in various human cancer cell lines. The galectin-9 antitumor effect against hepatocellular carcinoma (HCC) is, however, unknown. We investigated whether galectin-9 suppresses HCC growth in vitro and in vivo. We assessed the antitumor effect of galectin-9 on HCC cells by conducting WST-8 assay in vitro and xenograft model analysis in vivo. Galectin-9-induced apoptosis was evaluated by FACS and ELISA in vitro and by TUNEL stain in vivo. Cell cycle alteration was profiled by FACS. Caspases were profiled by colorimetry. MicroRNAs related to the galectin-9 antitumor effects were determined using microarrays, and their antitumor effect was confirmed in a transfection study in vitro. The expression levels of the target proteins of the miRNAs extracted above were analyzed by western blot analysis. To summarize the results, galectin-9 inhibited the growth of the HCC cell lines HLE and Li-7 in vitro and Li-7 in vivo inducing apoptosis. Cell cycle turnover was not arrested in HLE and Li-7 cells in vitro. miR-1246 was similarly extracted both in vitro and in vivo, which sensitized Li-7 cells to apoptosis when transfected into the cells. DYRK1A, a target protein of miR-1246 was downregulated in Li-7 cells. Caspase-9 was upregulated in Li-7 cells in vitro and in vivo. In conclusion, galectin-9 inhibited the growth of HCC cells by apoptosis, but not cell cycle arrest, in vitro and in vivo. miR-1246 mediated signals of galectin-9, possibly through miR-1246-DYRK1A-caspase-9 axis. Galectin-9 might be a candidate agent for HCC chemotherapy.

Abstract. Metformin is a commonly used oral antihyperglycemic agent of the biguanide family. Recent studies suggest that metformin may reduce cancer risk and improve prognosis. However, the antitumor mechanism of metformin in several types of cancers, including hepatocellular carcinoma (HCC), has not been elucidated. The goal of the present study was to evaluate the effects of metformin on HCC cell proliferation in vitro and in vivo, and to study microRNAs (miRNAs) associated with the antitumor effect of metformin in vitro. We used the cell lines Alex, HLE and Huh7, and normal hepatocytes to study the effects of metformin on human HCC cells. In an in vivo study, athymic nude mice bearing xenograft tumors were treated with metformin or left untreated. Tumor growth was recorded after 4 weeks, and the expression of cell cycle-related proteins was determined. Metformin inhibited the proliferation of Alex, HLE and Huh7 cells in vitro and in vivo. Metformin blocked the cell cycle in G0/G1 in vitro and in vivo. This blockade was accompanied by a strong decrease of G1 cyclins, especially cyclin D1, cyclin E and cyclin-dependent kinase 4 (Cdk4). In addition, microRNA (miRNA) expression was markedly altered by the treatment with metformin in vitro and in vivo. In addition, various miRNAs induced by metformin also may contribute to the suppression of tumor growth. Our results demonstrate that metformin inhibits the growth of HCC, possibly by inducing G1 cell cycle arrest through the alteration of microRNAs.

Hepatocellular carcinoma (HCC) is the seventh most frequent cancer and the fourth leading cause of cancer mortality worldwide. Despite substantial advances in therapeutic strategies, the prognosis of late-stage HCC remains dismal because of the high recurrence rate. A better understanding of the etiology of HCC is therefore necessary to improve outcomes. MicroRNAs (miRNAs) are small, endogenous, noncoding, single-stranded RNAs that modulate the expression of their target genes at the posttranscriptional and translational levels. Aberrant expression of miRNAs has frequently been detected in cancer-associated genomic regions or fragile sites in various human cancers and has been observed in both HCC cells and tissues. The precise patterns of aberrant miRNA expression differ depending on disease etiology, including various causes of hepatocarcinogenesis, such as viral hepatitis, alcoholic liver disease, or nonalcoholic steatohepatitis. However, little is known about the underlying mechanisms and the association of miRNAs with the pathogenesis of HCC of various etiologies. In the present review, we summarize the key mechanisms of miRNAs in the pathogenesis of HCC and emphasize their potential utility as valuable diagnostic and prognostic biomarkers, as well as innovative therapeutic targets, in HCC diagnosis and treatment.

Background: Although atezolizumab plus bevacizumab (Atez/bev) treatment has been developed for unresectable hepatocellular carcinoma (u-HCC), changes in hepatic function during therapy have yet to be reported.

Background/Aim Atezolizumab plus bevacizumab (Atez/Bev) treatment is recommended for unresechepatocellular carcinoma (u‐HCC) patients classified as Child‐Pugh A (CP‐A). This study aimed to elucidate the prognosis of patients treated with Atez/Bev, especially CP‐A and ‐B cases. Materials/methods From September 2020 to March 2022, 457 u‐HCC patients treated with Atez/Bev were enrolled (median age 74 years, male:female = 368:89, CP‐A:CP‐B = 427:30, Child‐Pugh score [CPS] 5:6:7:8:9 = 271:156:21:8:1). Therapeutic response was evaluated using RECIST ver.1.1. Clinical features and prognosis were retrospectively evaluated. Results There were no significant differences between CP‐A and ‐B patients in regard to best response (CR:PR:SD:PD = 16:91:194:81 vs. 0:7:13:8, p = 0.739; objective response rate/disease control rate = 28.0%/78.8% vs. 25.0%/71.4%). Analysis performed using inverse probability weighting adjustments of clinical factors other than those related to hepatic reserve function with a p value < 0.10 for comparisons between patients with CP‐A and ‐B showed that the progression‐free survival (PFS) rate for CP‐A cases was better (6‐/12‐/18‐month: 58.2%/36.1%/27.8% vs. 49.6%/8.7%/non‐estimable [NE], p < 0.001), as was overall survival (OS) rate (6‐/12‐/18‐month: 89.9%/71.7%/51.4% versus 63.6%/18.4%/NE; p < 0.001). Median PFS (mPFS) and median OS (mOS) for the CPS‐5 were 9.5 months/NE, and 5.1/14.0 months for the CPS‐6 (both p < 0.001). Furthermore, for modified albumin‐bilirubin grade (mALBI)‐1/2a/2b, mPFS was 9.4/8.5/5.3 months (p < 0.001) and mOS was NE/17.8/13.4 months (p < 0.001). Conclusion Better hepatic function, such as mALBI grade 1 or 2a are thought to indicate a better condition for obtaining sufficient prognosis with Atez/Bev treatment for u‐HCC patients, whereas for CP‐B patients, who mainly shown an mALBI grade of 2b or 3, Atez/Bev might have less therapeutic efficacy.

Recent studies suggest that metformin, which is a member of the biguanide family and commonly used as an oral anti-hyperglycemic agent, may reduce cancer risk and improve prognosis of numerous types of cancer. However, the mechanisms underlying the antitumor effect of metformin on esophageal cancer remain unknown. The goal of the present study was to evaluate the effects of metformin on the proliferation of human ESCC in vitro, and to study changes in the expression profile of microRNAs (miRNAs), since miRNAs have previously been associated with the antitumor effects of metformin in other human cancers. The human ESCC cell lines T.T, KYSE30 and KYSE70 were used to study the effects of metformin on human ESCC in vitro. In addition, we used miRNA array tips to explore the differences between miRNAs in KYSE30 cells with and without metformin treatment. Metformin inhibited the proliferation of T.T, KYSE30 and KYSE70 cells in vitro. Metformin blocked the cell cycle in G0/G1 in vitro. This blockade was accompanied by a strong decrease of G1 cyclins, especially cyclin D1, as well as decreases in cyclin-dependent kinase (Cdk)4, Cdk6 and phosphorylated retinoblastoma protein (Rb). In addition, the expression of miRNAs was markedly altered with the treatment of metformin in vitro. Metformin inhibited the growth of three ESCC cell lines, and this inhibition may have involved reductions in cyclin D1, Cdk4 and Cdk6.