Objective: To compare neoadjuvant chemotherapy (nCT) with CAPOX alone versus neoadjuvant chemoradiotherapy (nCRT) with capecitabine in locally advanced rectal cancer (LARC) with uninvolved mesorectal fascia (MRF). Background Data: nCRT is associated with higher surgical complications, worse long-term functional outcomes, and questionable survival benefits. Comparatively, nCT alone seems a promising alternative treatment in lower-risk LARC patients with uninvolved MRF. Methods: Patients between June 2014 and October 2020 with LARC within 12 cm from the anal verge and uninvolved MRF were randomly assigned to nCT group with 4 cycles of CAPOX (Oxaliplatin 130 mg/m2 IV day 1 and Capecitabine 1000 mg/m2 twice daily for 14 d. Repeat every 3 wk) or nCRT group with Capecitabine 825 mg/m² twice daily administered orally and concurrently with radiation therapy (50 Gy/25 fractions) for 5 days per week. The primary end point is local-regional recurrence-free survival. Here we reported the results of secondary end points: histopathologic response, surgical events, and toxicity. Results: Of the 663 initially enrolled patients, 589 received the allocated treatment (nCT, n=300; nCRT, n=289). Pathologic complete response rate was 11.0% (95% CI, 7.8-15.3%) in the nCT arm and 13.8% (95% CI, 10.1-18.5%) in the nCRT arm (P=0.33). The downstaging (ypStage 0 to 1) rate was 40.8% (95% CI, 35.1-46.7%) in the nCT arm and 45.6% (95% CI, 39.7-51.7%) in the nCRT arm (P=0.27). nCT was associated with lower perioperative distant metastases rate (0.7% vs. 3.1%, P=0.03) and preventive ileostomy rate (52.2% vs. 63.6%, P=0.008) compared with nCRT. Four patients in the nCT arm received salvage nCRT because of local disease progression after nCT. Two patients in the nCT arm and 5 in the nCRT arm achieved complete clinical response and were treated with a nonsurgical approach. Similar results were observed in subgroup analysis. Conclusions: nCT achieved similar pCR and downstaging rates with lower incidence of perioperative distant metastasis and preventive ileostomy compared with nCRT. CAPOX could be an effective alternative to neoadjuvant therapy in LARC with uninvolved MRF. Long-term follow-up is needed to confirm these results.

Background: Metabolic reprograming have been associated with cancer occurrence and progression within the tumor immune microenvironment. However, the prognostic potential of metabolism-related genes in colorectal cancer (CRC) has not been comprehensively studied. Here, we investigated metabolic transcript-related CRC subtypes and relevant immune landscapes, and developed a metabolic risk score (MRS) for survival prediction. Methods: Metabolism-related genes were collected from the Molecular Signatures Database and metabolic subtypes were identified using an unsupervised clustering algorithm based on the expression profiles of survival-related metabolic genes in GSE39582. The ssGSEA and ESTIMATE methods were applied to estimate the immune infiltration among subtypes. The MRS model was developed using LASSO Cox regression in the GSE39582 dataset and independently validated in the TCGA CRC and GSE17537 datasets. Results: We identified two metabolism-related subtypes (cluster-A and cluster-B) of CRC based on the expression profiles of 539 survival-related metabolic genes with distinct immune profiles and notably different prognoses. The cluster-B subtype had a shorter OS and RFS than the cluster-A subtype. Eighteen metabolism-related genes that were mostly involved in lipid metabolism pathways were used to build the MRS in GSE39582. Patients with higher MRS had worse prognosis than those with lower MRS (HR 3.45, P < 0.001). The prognostic role of MRS was validated in the TCGA CRC (HR 2.12, P = 0.00017) and GSE17537 datasets (HR 2.67, P = 0.039). Time-dependent receiver operating characteristic curve and stratified analyses revealed the robust predictive ability of the MRS in each dataset. Multivariate Cox regression analysis indicted that the MRS could predict OS independent of TNM stage and age. Conclusions: Our study provides novel insight into metabolic heterogeneity and its relationship with immune landscape in CRC. The MRS was identified as a robust prognostic marker and may facilitate individualized therapy for CRC patients.

Background: As the selective inhibitor of BRAF kinase, vemurafenib exhibits effective antitumor activities in patients with V600 BRAF mutant melanomas. However, acquired drug resistance invariably develops after its initial treatment. Methods: Immunohistochemical staining was performed to detect the expression of iNOS and hTERT, p-p65, Epcam, CD44, PCNA in mice with melanoma xenografts. The proliferation and migration of melanoma cells were detected by MTT, tumorsphere culture, cell cycle, cell apoptosis, AO/EB assay and colony formation, transwell assay and scratch assay in vitro, and tumor growth differences were observed in xenograft nude mice. Changes in the expression of key molecules in the iNOS/hTERT signaling pathways were detected by western blot. Nucleus-cytoplasm separation, and immunofluorescence analyses were conducted to explore the location of p50/p65 in melanoma cell lines. Flow cytometry assay were performed to determine the expression of CD44. Pull down assay and ChIP assay were performed to detect the binding ability of p65 at iNOS and hTERT promoters. Additionally, hTERT promoter-driven luciferase plasmids were transfected in to melanoma cells with indicated treatment to determine luciferase activity of hTERT. Results: Melatonin significantly and synergistically enhanced vemurafenib-mediated inhibitions of proliferation, colony formation, migration and invasion and promoted vemurafenib-induced apoptosis, cell cycle arresting and stemness weakening in melanoma cells. Further mechanism study revealed that melatonin enhanced the antitumor effect of vemurafenib by abrogating nucleus translocation of NF-κB p50/p65 and their binding at iNOS and hTERT promoters, thereby suppressing the expression of iNOS and hTERT. The elevated anti-tumor capacity of vemurafenib upon co-treatment with melatonin was also evaluated and confirmed in mice with melanoma xenografts. Conclusions: Collectively, our results demonstrate melatonin synergizes the antitumor effect of vemurafenib in human melanoma by inhibiting cell proliferation and cancer-stem cell traits via targeting NF-κB/iNOS/hTERT signaling pathway, and suggest the potential of melatonin in antagonizing the toxicity of vemurafenib and augmenting its sensitivities in melanoma treatment.

Colorectal cancer, a leading cause of global cancer-related morbidity and mortality, poses a significant challenge with its incidence rising. 5-fluorouracil (5-FU), a key chemotherapy agent, faces the challenge of drug resistance. Clock genes, which regulate circadian rhythms, are linked to tumor occurrence, progression, and treatment responses, and are often abnormally expressed in many tumors. Ferroptosis, a non-apoptotic form of cell death, plays a role in tumor drug resistance. Recent research indicates that clock genes may influence tumor cells' sensitivity to ferroptosis by regulating cellular metabolism and oxidative stress responses. Through bioinformatics analysis, we identified the clock gene ARNTL2 as a key factor associated with chemoresistance. ARNTL2 was found to be significantly overexpressed in colon cancer, and was closely correlated with poor prognosis. Experimental validation using in vitro and in vivo models demonstrated that ARNTL2 promotes resistance to 5-FU by upregulating SLC7A11, a critical regulator of ferroptosis. Mechanistically, ARNTL2 directly binds to the SLC7A11 promoter and enhances its transcription, while also influencing SLC7A11 mRNA stability through PHGDH. These findings establish the ARNTL2-SLC7A11 axis as an important mechanism driving ferroptosis resistance and chemoresistance in colon cancer. Furthermore, we explored the therapeutic potential of melatonin (Mlt), a circadian-regulating hormone, and discovered that Mlt can degrade ARNTL2 via the ubiquitination-proteasome pathway, thereby downregulating the ARNTL2-SLC7A11 axis. Our results highlight ARNTL2 as a promising biomarker for predicting chemoresistance and prognosis in colon cancer patients. Additionally, the ability of Mlt to enhance chemotherapy sensitivity by targeting the ARNTL2-SLC7A11 axis offers a novel, low-toxicity strategy for improving treatment outcomes. These findings bridge the fields of chronobiology and oncology, providing new insights for precision medicine approaches in colon cancer.

Background: The prognosis of locally unresectable colon cancer (CC) is poor. This prospective observational study aimed to further evaluate the feasibility and efficacy of neoadjuvant chemoradiotherapy (NACRT) followed by surgery in these patients. Patients and methods: We consecutively enrolled patients who were diagnosed with locally unresectable CC from November 2010 to March 2017, and received NACRT followed by surgery. The data of all the patients were collected prospectively. The R0 resection, downstage and pathologic complete response (pCR) rates were calculated to evaluate the short-term treatment effects. The overall survival (OS) was used to evaluate the long-term outcome. The incidence of NACRT-related acute toxicities and postsurgical complications were used to assess the safety. Results: A total of 60 patients were eligible for analysis, including 57 (95.0%) patients who attained resectability after NACRT. Among patients managed with surgery, 49 cases (86.0%) achieved R0 resection, and 15 cases (26.3%) achieved pCR. Down T stage was seen in 47 cases (82.5%), and down N stage was seen in 53 cases (93.0%). After a median follow-up time of 26 months, the OS appeared as 76.7%. The most common grade 3/4 NACRT-related toxicity was myelosuppression (incidence, 20.0%). The incidence of grade 3/4 surgery-related complication was 7.0%. Conclusion: NACRT might be a safe and effective choice for patients with locally unresectable CC to improve treatment effects, long-term survival and life quality, though further validation is needed.