Aim: MTHFD1 was the enzyme providing one-carbon derivatives of tetrahydrofolate. We sought to investigate the impact of MTHFD1 on hepatocellular carcinoma (HCC). Methods: Bioinformatic analysis, western blot and immunohistochemistry were conducted to detect MTHFD1 expression in HCC. The relationships between MTHFD1 and prognosis of 172 HCCs were analyzed by Kaplan–Meier method and Cox proportional hazards model. Results: High MTHFD1 expression in HCC represented poor prognosis (overall survival p = 0.025; time to recurrence p = 0.044). Combining MTHFD1 with serum AFP, survival analysis demonstrated the prognosis of the MTHFD1 low expression and AFP ≤20 ng/ml group was better than that of the MTHFD1 high expression or AFP >20 ng/ml group and the MTHFD1 high expression and AFP >20 ng/ml group (overall survival p < 0.0001; time to recurrence p < 0.0001). Conclusion: High MTHFD1 expression in HCC indicated poorer prognosis. Combining MTHFD1 with serum AFP improved the accuracy of prognostic prediction.

Background: Despite recent advances in the treatment of hepatocellular carcinoma (HCC), the chemotherapy efficacy against HCC is still unsatisfactory. The mammalian target of rapamycin (mTOR) has been emerged as an important cancer therapeutic target. However, HCC cells often resistant to rapamycin because of the paradoxical activation of Akt by rapamycin. In this study, we investigated whether bortezomib could enhance the antitumor effects of rapamycin. Methods: The effects of rapamycin and bortezomib on HCC proliferation, apoptosis, migration, and invasiveness in vitro were assessed by CCK-8 analysis, flow cytometry, Hoechst 33342 staining and transwell assays, respectively. Total and phosphorylated protein levels of Akt were detected by Western blotting. The effects of rapamycin and/or bortezomib on the mRNA expression levels of p53, p27, p21 and Bcl-2 family in HCCLM3 cells were evaluated by RT-PCR. The roles of rapamycin and bortezomib on HCC growth and metastasis in xenograft models were evaluated by tumor volumes and fluorescent signals. The effects of rapamycin and bortezomib on cell proliferation and apoptosis in vivo were test by PCNA and TUNEL staining. Results: Bortezomib synergized with rapamycin to reduce cell growth, induce apoptosis, and inhibit cell mobility in vitro. Further mechanistic studies showed that bortezomib inhibited rapamycin-induced phosphorylated Akt, which in turn enhanced apoptosis of HCC cell lines. The alteration of the mRNA expression of cell cycle inhibitors p53, p27, p21 and apoptosis associated genes Bcl-2, Bax were also involved in the synergistic antitumor effects of rapamycin and bortezomib. P53 inhibitor PFT-α significantly attenuate the effect of rapamycin and bortezomib on cell apoptosis, which indicated that the pro-apoptotic effect of rapamycin and bortezomib may be p53-dependent. Treatment of HCCLM3-R bearing nude mice with rapamycin and bortezomib significantly enhanced tumor growth inhibition (72.4%), comparing with either rapamycin- (54.7%) or bortezomib-treated mice (22.4%). In addition, the lung metastasis was significantly suppressed in mice received the combination treatment (16.6%). The combination treatment of rapamycin and bortezomib significantly inhibited tumor cell proliferation and tumor angiogenesis in vivo. Conclusion: The combination of rapamycin with bortezomib could be a novel and promising therapeutic approach to the treatment of HCC.

Niemann-Pick C1-like 1 (NPC1L1) and Niemann-Pick C2 (NPC2) is a critical mediator of cholesterol absorption. The aim of the present study was to investigate the prognostic value of NPC1L1 and NPC2 in human primary hepatocellular carcinoma (HCC). The expression level of NPC1L1 and NPC2 were evaluated by Immunohistochemistry, Westen blot and Real-time Quantitative PCR. Protein expression level in tissue was represented by integral optic density (IOD). For prognosis analyses, outcome-based cut-point was calculated by X-tile software. Kaplan-Meier analysis, Cox regression analysis were used evaluate prognostic value of NPC1L1 and NPC2 and NPC1L1/NPC2 combination. Both of NPC1L1 and NPC2 were significantly decreased in HCC tissues than peritumoral liver tissues (61 pairs of tissue for Immunohistochemistry and 10 pairs of tissues for Western blot and Real-time Quantitative PCR), respectively. (n=61: p=0.0005 for NPC1L1 and p=0.0001 for NPC2; n=10: p=0.0002 for NPC1L1 and p=0.0489 for NPC2). Kaplan-Meier analyses in 265 HCC cases were showed that the low expression level of NPC1L1 and NPC2 and NPC1L1/NPC2 combination were significantly correlated with poor overall survival (OS) and shorter time to recurrence (TTR). In addition, univariate and multivariate Cox analyses showed that the expression level of NPC1L1/NPC2 combination in HCC was an independent prognostic factor for OS and TTR. Conclusion: NPC1L1 and NPC2 were lowly expressed in HCC compared with peritumoral liver tissues, and low expression of NPC1L1 and NPC2 in HCC tissues may indicate poor outcome of HCC patients after surgery. NPC1L1/NPC2 combination is an independent prognostic factor for OS and TTR in postoperative HCC patients.

Background: Differential diagnosis of high-grade dysplastic nodules (HGDN) and well-differentiated hepatocellular carcinoma (WDHCC) represents a challenge to experienced hepatic clinicians, radiologists and hepatopathologists. Methods: The expression profiles of aminoacylase-1 (ACY1), sequestosome-1 (SQSTM1) and glypican-3 (GPC3) in low-grade dysplastic nodules (LGDN), HGDN and WDHCC were assessed by immunohistochemistry. The differential diagnostic performances of these three markers alone and in combination for HGDN and WDHCC were investigated by logistic regression models (HGDN = 21; WDHCC = 32) and validated in an independent test set (HGDN, n = 21; WDHCC n = 24). Postoperative overall survival and time to recurrence were evaluated by univariate and multivariate analyses in an independent set of 500 patients. Results: ACY1, SQSTM1 and GPC3 were differentially expressed in each group. For the differential diagnosis of WDHCC from HGDN, the sensitivity and specificity of the combination of ACY1 + SQSTM1 + GPC3 for detecting WDHCC were 93.8% and 95.2% respectively in the training set, which were higher than any of the three two-marker combinations. The validities of the four diagnostic models were further confirmed in an independent test set, and corresponding good sensitivity and specificity were observed. Interestingly, GPC3 expression in HCC tissues combined with serum α-fetoprotein (AFP) was found to be an independent predictor for overall survival and time to recurrence. Conclusions: ACY1 + SQSTM1 + GPC3 combination represents a potentially valuable biomarker for distinguishing between WDHCC and HGDN using immunohistochemistry. Meanwhile, low GPC3 staining combined with positive serum AFP may play a practical role in predicting poor postoperative outcome and high tumor recurrence risk.

Ferroptosis, a unique form of iron-dependent cell death triggered by lipid peroxidation accumulation, holds great promise for cancer therapy. Despite the crucial role of GPX4 in regulating ferroptosis, our understanding of GPX4 protein regulation remains limited. Through FACS-based genome-wide CRISPR screening, we identified MALT1 as a regulator of GPX4 protein. Inhibition of MALT1 expression enhances GPX4 ubiquitination-mediated degradation by up-regulating the E3 ubiquitin ligase RC3H1. Using both rescue assays and functional genetic screening, we demonstrate that pharmacologically targeting MALT1 triggers ferroptosis in liver cancer cells. Moreover, we show that targeting MALT1 synergizes with sorafenib or regorafenib to induce ferroptosis across multiple cancer types. These findings elucidate the modulatory effects of the MALT1–RC3H1 axis on GPX4 stability, revealing a molecular mechanism that could be exploited to induce ferroptosis for cancer therapy.