Fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m⁶A) demethylase, participates in tumor progression and metastasis in many malignancies, but its role in colorectal cancer (CRC) is still unclear. Here, we found that FTO protein levels, but not RNA levels, were downregulated in CRC tissues. Reduced FTO protein expression was correlated with a high recurrence rate and poor prognosis in resectable CRC patients. Moreover, we demonstrated that hypoxia restrained FTO protein expression, mainly due to an increase in ubiquitin-mediated protein degradation. The serine/threonine kinase receptor associated protein (STRAP) might served as the E3 ligase and K216 was the major ubiquitination site responsible for hypoxia-induced FTO degradation. FTO inhibited CRC metastasis both in vitro and in vivo. Mechanistically, FTO exerted a tumor suppressive role by inhibiting metastasis-associated protein 1 (MTA1) expression in an m⁶A-dependent manner. Methylated MTA1 transcripts were recognized by an m⁶A “reader”, insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), which then stabilized its mRNA. Together, our findings highlight the critical role of FTO in CRC metastasis and reveal a novel epigenetic mechanism by which the hypoxic tumor microenvironment promotes CRC metastasis.

Summary: A recent study indicated that Lectin‐type oxidized LDL receptor‐1 (LOX‐1) was a distinct surface marker for human polymorphisms myeloid‐derived suppressor cells (PMN‐MDSC). The present study was aimed to investigate the existence LOX‐1 PMN‐MDSC in hepatocellular carcinoma (HCC) patients. One hundred and twenty‐seven HCC patients, 10 patients with mild active chronic hepatitis B, 10 liver cirrhosis due to hepatitis B, 10 liver dysplastic node with hepatitis B and 50 health control were included. LOX‐1⁺ CD15⁺ PMN‐MDSC were significantly elevated in HCC patients compared with healthy control and patients with benign diseases. LOX‐1⁺ CD15⁺ PMN‐MDSC in circulation were positively associated with those in HCC tissues. LOX‐1⁺ CD15⁺ PMN‐MDSCs significantly reduced proliferation and IFN‐γ production of T cells with a dosage dependent manner with LOX‐1⁻ CD15⁺ PMNs reached negative results. The suppression on T cell proliferation and IFN‐γ production was reversed by ROS inhibitor and Arginase inhibitor. ROS level and activity of arginase of LOX‐1 ⁺CD15⁺ PMN were higher in LOX‐1⁺ CD15⁺ PMN‐MDSCs than LOX‐1⁻ CD15⁺ PMNs, as well as the expression of the NADPH oxidase NOX2 and arginase I. RNA sequence revealed that LOX‐1⁺ CD15⁺ PMN‐MDSCs displayed significantly higher expression of spliced X‐box ‐binding protein 1 (sXBP1), an endoplasmic reticulum (ER) stress marker. ER stress inducer induced LOX‐1 expression and suppressive function for CD15⁺ PMN from health donor. For HCC patients, LOX‐1⁺ CD15⁺ PMN‐MDSCs were positively related to overall survival. Above all, LOX‐1⁺ CD15⁺ PMN‐MDSC were elevated in HCC patients and suppressed T cell proliferation through ROS/Arg I pathway induced by ER stress. They presented positive association with the prognosis of HCC patients.

AIM: To investigate the prognostic value of preoperative lymphocyte-to-monocyte ratio (LMR) in patients with hepatocellular carcinoma (HCC) undergoing curative hepatectomy. METHODS: Clinicopathological data of 210 hepatitis B virus (HBV)-associated HCC patients who were treated by radical hepatic resection between 2003 and 2010 were retrospectively analyzed. None of the patients received any preoperative anticancer therapy or intraoperative radiofrequency ablation. The diagnosis was confirmed by pathological examination after surgery. Absolute peripheral blood lymphocyte and monocyte counts were derived from serum complete blood cell count before surgery, and LMR was calculated by dividing lymphocyte count by monocyte count. The best cutoff was determined by receiver operating characteristics (ROC) curve analysis. Correlations between LMR levels and clinicopathological features were assessed using the χ² test. Survival outcomes were estimated using the Kaplan-Meier method and compared by the log-rank test. Univariate and multivariate analyses were performed to evaluate the prognostic impact of LMR and other clinicopathological factors on overall survival (OS) and recurrence-free survival (RFS), using the Cox proportional hazards model. RESULTS: The optimal cutoff value of LMR for survival analysis was 3.23, which resulted in the most appropriate sensitivity of 55.3% and specificity of 74.7%, with the area under the curve (AUC) of 0.66 (95%CI: 0.593-0.725). All patients were dichotomized into either a low (≤ 3.23) LMR group (n = 66) or a high (> 3.23) LMR group (n = 144). A low preoperative LMR level was significantly correlated with the presence of cirrhosis, elevated levels of total bilirubin and larger tumor size. Patients with a low LMR level had significantly reduced 5-year OS (61.9% vs 83.2%, P < 0.001) and RFS (27.8% vs 47.6%, P = 0.009) compared to those with a high LMR level. Multivariate analyses indicated that a lower LMR level was a significantly independent predictor of inferior OS (P = 0.003) and RFS (P = 0.006). Subgroup analysis indicated that survival outcome was significantly more favorable in cirrhotic patients with LMR > 3.23. However, there were no differences between low and high LMR groups for OS and RFS in non-cirrhotic patients. CONCLUSION: Preoperative LMR was demonstrated for the first time to serve as an independent prognostic factor in HBV-associated HCC patients after curative resection. Prospective studies with larger cohorts for validation are warranted.

Purpose: To compare the efficacy and safety of high-dose vitamin C plus FOLFOX ± bevacizumab versus FOLFOX ± bevacizumab as first-line treatment in patients with metastatic colorectal cancer (mCRC). Patients and Methods: Between 2017 and 2019, histologically confirmed patients with mCRC (n = 442) with normal glucose-6-phosphate dehydrogenase status and no prior treatment for metastatic disease were randomized (1:1) into a control (FOLFOX ± bevacizumab) and an experimental [high-dose vitamin C (1.5 g/kg/d, intravenously for 3 hours from D1 to D3) plus FOLFOX ± bevacizumab] group. Randomization was based on the primary tumor location and bevacizumab prescription. Results: The progression-free survival (PFS) of the experimental group was not superior to the control group [median PFS, 8.6 vs. 8.3 months; HR, 0.86; 95% confidence interval (CI), 0.70–1.05; P = 0.1]. The objective response rate (ORR) and overall survival (OS) of the experimental and control groups were similar (ORR, 44.3% vs. 42.1%; P = 0.9; median OS, 20.7 vs. 19.7 months; P = 0.7). Grade 3 or higher treatment-related adverse events occurred in 33.5% and 30.3% of patients in the experimental and control groups, respectively. In prespecified subgroup analyses, patients with RAS mutation had significantly longer PFS (median PFS, 9.2 vs. 7.8 months; HR, 0.67; 95% CI, 0.50–0.91; P = 0.01) with vitamin C added to chemotherapy than with chemotherapy only. Conclusions: High-dose vitamin C plus chemotherapy failed to show superior PFS compared with chemotherapy in patients with mCRC as first-line treatment but may be beneficial in patients with mCRC harboring RAS mutation.