LAMTOR1 ablation impedes cGAS degradation caused by chemotherapy and promotes antitumor immunity.

Chemotherapy resistance remains a significant obstacle that limits the long-term efficacy of cancer therapy, necessitating further investigations into the underlying mechanisms. Here, we find that DNA fragments induced by chemotherapeutic agents trigger the degradation of cGAS, a potent double-strand DNA (dsDNA) sensor, by lysosomes. Mechanically, the lysosome-localized protein LAMTOR1 is up-regulated, and the interaction between LAMTOR1 and cGAS is enhanced upon exposure to DNA fragments, boosting the accumulation and digestion of cGAS in lysosomes through the receptor protein p62. LAMTOR1 deficiency increases cGAS abundance and promotes activation of the cGAS-STING pathway, leading to subsequent production of type I interferons induced by cytosolic DNA stimulation. Loss of LAMTOR1 synergizes with immunotherapy and chemotherapy to inhibit tumor growth and prolong the survival time of tumor-bearing mice by promoting the infiltration of effective T lymphocytes. Thus, our study reveals a regulation of cGAS abundance and provides a potential strategy to overcome chemotherapy resistance by targeting LAMTOR1.

Distal margin distance in radical resection of locally advanced rectal cancer after neoadjuvant therapy.

Colorectal cancer has a high incidence and mortality rate in China, with the majority of cases being middle and low rectal cancer. Surgical intervention is currently the main treatment modality for locally advanced rectal cancer, with the common goal of improving oncological outcomes while preserving function. The controversy regarding the circumferential resection margin distance in rectal cancer surgery has been resolved. With the promotion of neoadjuvant therapy concepts and advancements in technology, treatment strategies have become more diverse. Following tumor downstaging, there is an increasing trend towards extending the safe distance of distal rectal margin. This provides more opportunities for patients with low rectal cancer to preserve their anal function. However, there is currently no consensus on the specific distance of distal resection margin.

Potential crosstalk between SPP1 + TAMs and CD8 + exhausted T cells promotes an immunosuppressive environment in gastric metastatic cancer.

BACKGROUND: Immunotherapy brings new hope to patients with advanced gastric cancer. However, liver metastases can reduce the efficacy of immunotherapy in patients. Tumor-associated macrophages (TAMs) may be the cause of this reduction in efficacy. SPP1 + TAMs are considered to have immunosuppressive properties. We aimed to investigate the involvement of SPP1 + TAMs in the metastasis of gastric cancer. METHODS: The single-cell transcriptome was combined with batched BULK datasets for analysis. Animal models were used to verify the analysis results. RESULTS: We reveal the interaction of SPP1 + TAMs with CD8 + exhausted T cells in metastatic cancer. Among these interactions, GDF15-TGFBR2 may play a key immunosuppressive role. We constructed an LR score to quantify interactions based on ligands and receptors. The LR score is highly correlated with various immune features and clinical molecular subtypes. The LR score may also guide the prediction of the efficacy of immunotherapy and prognosis. CONCLUSIONS: The crosstalk between SPP1 + TAMs and CD8 + exhausted T cells plays a key immunosuppressive role in the gastric metastatic cancer microenvironment.

Application of Single-Cell Sequencing Technology in Research on Colorectal Cancer.

Colorectal cancer (CRC) is the third most prevalent and second most lethal cancer globally, with gene mutations and tumor metastasis contributing to its poor prognosis. Single-cell sequencing technology enables high-throughput analysis of the genome, transcriptome, and epigenetic landscapes at the single-cell level. It offers significant insights into analyzing the tumor immune microenvironment, detecting tumor heterogeneity, exploring metastasis mechanisms, and monitoring circulating tumor cells (CTCs). This article provides a brief overview of the technical procedure and data processing involved in single-cell sequencing. It also reviews the current applications of single-cell sequencing in CRC research, aiming to enhance the understanding of intratumoral heterogeneity, CRC development, CTCs, and novel drug targets. By exploring the diverse molecular and clinicopathological characteristics of tumor heterogeneity using single-cell sequencing, valuable insights can be gained into early diagnosis, therapy, and prognosis of CRC. Thus, this review serves as a valuable resource for identifying prognostic markers, discovering new therapeutic targets, and advancing personalized therapy in CRC.

Risk factors for anastomotic leak and postoperative morbidity after right hemicolectomy for colon cancer: results from a prospective, multi-centre, snapshot study in China.

BACKGROUND: Right hemicolectomy is the standard treatment for right-sided colon cancer. There is variation in the technical aspects of performing right hemicolectomy as well as in short-term outcomes. It is therefore necessary to explore best clinical practice following right hemicolectomy in expert centres. METHODS: This snapshot study of right hemicolectomy for colon cancer in China was a prospective, multicentre cohort study in which 52 tertiary hospitals participated. Eligible patients with stage I-III right-sided colon cancer who underwent elective right hemicolectomy were consecutively enrolled in all centres over 10 months. The primary endpoint was the incidence of postoperative 30-day anastomotic leak. RESULTS: Of the 1854 patients, 89.9 per cent underwent laparoscopic surgery and 52.3 per cent underwent D3 lymph node dissection. The overall 30-day morbidity and mortality were 11.7 and 0.2 per cent, respectively. The 30-day anastomotic leak rate was 1.4 per cent. In multivariate analysis, ASA grade > II (P < 0.001), intraoperative blood loss > 50 ml (P = 0.044) and D3 lymph node dissection (P = 0.008) were identified as independent risk factors for postoperative morbidity. Extracorporeal side-to-side anastomosis (P = 0.031), intraoperative blood loss > 50 ml (P = 0.004) and neoadjuvant chemotherapy (P = 0.004) were identified as independent risk factors for anastomotic leak. CONCLUSION: In high-volume expert centres in China, laparoscopic resection with D3 lymph node dissection was performed in most patients with right-sided colon cancer, and overall postoperative morbidity and mortality was low. Further studies are needed to explore the optimal technique for right hemicolectomy in order to improve outcomes further.

Histone deacetylase-mediated tumor microenvironment characteristics and synergistic immunotherapy in gastric cancer.

Background: Studies have shown that the expression of histone deacetylases (HDACs) is significantly related to the tumor microenvironment (TME) in gastric cancer. However, the expression of a single molecule or several molecules does not accurately reflect the TME characteristics or guide immunotherapy in gastric cancer. Methods: We constructed an HDAC score (HDS) based on the expression level of HDACs. The single-cell transcriptome was used to analyze the underlying factors contributing to differences in immune infiltration between patients with a high and low HDS. In vitro and in vivo experiments validated the strategy of transforming cold tumors into hot tumors to guide immunotherapy. Results: According to the expression characteristics of HDACs, we constructed an HDS model to characterize the TME. We found that patients with a high HDS had stronger immunogenicity and could benefit more from immunotherapy than those with a low score. The AUC value of the HDS combined with the combined positive score (CPS)for predicting the efficacy of immunotherapy was as high as 0.96. By single-cell and paired bulk transcriptome sequencing analysis, we found that the infiltration levels of CD4+ T cells, CD8+ T cells and NK cells were significantly decreased in the low HDS group, which may be induced by MYH11+ fibroblasts, CD234+ endothelial cells and CCL17+ pDCs via the MIF signaling pathway. Inhibition of the MIF signaling pathway was confirmed to potentially enhance immune infiltration. In addition, our analysis revealed that GPX4 inhibitors might be effective for patients with a low HDS. GPX4 knockout significantly inhibited PD-L1 expression and promoted the infiltration and activation of CD8+ T cells. Conclusion: We constructed an HDS model based on the HDAC expression characteristics of gastric cancer. This model was used to evaluate TME characteristics and predict immunotherapy efficacy. Inhibition of the MIF signaling pathway in the TME and GPX4 expression in tumor cells may be an important strategy for cold tumor synergistic immunotherapy for gastric cancer.

IDH1 K224 acetylation promotes colorectal cancer via miR-9-5p/NHE1 axis-mediated regulation of acidic microenvironment.

The acidic microenvironment is considered an important factor in colorectal cancer (CRC) that contributes to malignant transformation. However, the underlying mechanism remains unclear. In a previous study, we confirmed that IDH1 K224 deacetylation promotes enzymatic activity and the production of α-KG. Here, we further investigate the effect of IDH1 hyperacetylation on the CRC acidic microenvironment. We demonstrate that increased α-KG affects hydroxylation of Ago2 and mediates miR-9-5p targeting NHE1 protein. Knockdown of NHE1 dramatically attenuates CRC cell proliferation and migration by restricting transport of intracellular H+ out of cells. Furthermore, we show that miR-9-5p is the microRNA with the most significant difference in the alteration of IDH1 K224 acetylation and can downregulate NHE1 mRNA. Our data also indicate that hydroxylation stabilizes Ago2, which in turn promotes miR-9-5p activity. Taken together, our results reveal a novel mechanism through which IDH1 deacetylation regulates the cellular acidic microenvironment and inhibits CRC metastasis.

Characteristics of alpha-fetoprotein-positive gastric cancer revealed by analysis of cancer databases and transcriptome sequencing data.

Gastric cancer is one of the most common malignant tumors in the world. Alpha fetoprotein (AFP)-positive gastric cancer (AFPP-GC) is considered a special entity among gastric cancers. There is still controversy regarding the clinicopathological characteristics and prognosis of AFPP-GC, and the potential mechanism underlying its high malignant potential is still unclear. A comprehensive description of AFPP-GC genomic characteristics and regulatory mechanisms is lacking. This study analyzed the pathological characteristics and prognosis of AFPP-GC by utilizing clinical samples. The results showed that AFPP-GC has a poor prognosis and a high of risk liver metastasis. Tissue transcriptome sequencing showed that genes with high expression in AFPP-GC were involved in the activation of various cancer pathways, and genes with low expression were involved in the immune response. Single-sample gene set enrichment analysis showed that overexpression of AFP in AFPP-GC significantly inhibited the infiltration of CD8+ T cells. To further explore the genomic characteristics of AFPP-GC, the signaling pathway by which AFP regulates the invasion and metastasis of AFPP-GC cells was discussed. The results showed that AFPP-GC may promote cell invasion by regulating the PTEN/AKT1/SOX5/CES1 signaling axis. This study reveals the molecular mechanism underlying the increased malignant potential of AFPP-GC vs. AFP-negative gastric cancer (AFPN-GC). This provides important information for individualized treatment of AFPP-GC.

Incidence, prevention, risk factors, and prediction of venous thromboembolism in Chinese patients after colorectal cancer surgery: a prospective, multicenter cohort study.

BACKGROUND: Venous thromboembolism (VTE) is a common and serious complication after colorectal cancer (CRC) surgery. Few large-sample studies have reported VTE incidence and management status after CRC surgery in China. This study aimed to investigate the incidence and prevention of VTE in Chinese patients after CRC surgery, identify risk factors for developing VTE, and construct a new scoring system for clinical decision-making and care planning. METHODS: Participants were recruited from 46 centers in 17 provinces in China. Patients were followed up for 1 month postoperatively. The study period was from May 2021 to May 2022. The Caprini score risk stratification and VTE prevention and incidence were recorded. The predictors of the occurrence of VTE after surgery were identified by multivariate logistic regression analysis, and a prediction model (CRC-VTE score) was developed. RESULTS: A total of 1836 patients were analyzed. The postoperative Caprini scores ranged from 1 to 16 points, with a median of 6 points. Of these, 10.1% were classified as low risk (0-2 points), 7.4% as moderate risk (3-4 points), and 82.5% as high risk (≥5 points). Among these patients, 1210 (65.9%) received pharmacological prophylaxis, and 1061 (57.8%) received mechanical prophylaxis. The incidence of short-term VTE events after CRC surgery was 11.2% (95% CI 9.8-12.7), including deep venous thrombosis (DVT) (11.0%, 95% CI 9.6-12.5) and pulmonary embolism (PE) (0.2%, 95% CI 0-0.5). Multifactorial analysis showed that age (≥70 years), history of varicose veins in the lower extremities, cardiac insufficiency, female sex, preoperative bowel obstruction, preoperative bloody/tarry stool, and anesthesia time at least 180 min were independent risk factors for postoperative VTE. The CRC-VTE model was developed from these seven factors and had good VTE predictive performance ( C -statistic 0.72, 95% CI 0.68-0.76). CONCLUSIONS: This study provided a national perspective on the incidence and prevention of VTE after CRC surgery in China. The study offers guidance for VTE prevention in patients after CRC surgery. A practical CRC-VTE risk predictive model was proposed.

Young adults with colon cancer: clinical features and surgical outcomes.

BACKGROUND: The clinicopathological features, surgical outcomes, and long-term survival of patients with young-onset colon cancer (≤ 40 years old) remain controversial. METHODS: The clinicopathologic and follow-up data of patients aged < 40 years with colon cancer between January 2014 and January 2022 were reviewed. The primary objectives were clinical features and surgical outcomes. Long-term survival was investigated as a secondary objective. RESULTS: Seventy patients were included in the study, and no significant rising trend (Z=0, P=1) of these patients was observed over the 8-year study period. Stage IV disease was accompanied by more ulcerative or infiltrating type (84.2% vs. 52.9%, P=0.017) and lymphovascular or perineural invasion (64.7% vs. 25.5%, P=0.003) than stage I-III disease. After a median follow-up time of 41 months (range 8-99 months), the 1-, 3-, and 5-year estimated overall survival (OS) rates were 92.6%, 79.5%, and 76.4%, respectively. The 1-, 3-, and 5-year progression-free survival (PFS) rates were 79.6%, 71.7%, and 71.7%, respectively. Multivariate Cox regression showed that M+ stage (hazard ratio [HR], 3.942; 95% confidence interval [CI], 1.176-13.220, P=0.026) was the only independent risk factor affecting OS. Meanwhile, tumor deposits (HR, 4.807; 95% CI, 1.942-15.488, P=0.009), poor differentiation (HR, 2.925; 95% CI, 1.012-8.454, P=0.047), and M+ stage (HR, 3.540; 95% CI, 1.118-11.202, P=0.032) independently affected PFS. CONCLUSIONS: The differences in the clinical features, surgical outcomes, and long-term survival between young adults and elderly colon cancer patients need further investigation.

Reshaping the tumour immune microenvironment in solid tumours via tumour cell and immune cell DNA methylation: from mechanisms to therapeutics.

In recent years, the tumour microenvironment (TME) of solid tumours has attracted more and more attention from researchers, especially those non-tumour components such as immune cells. Infiltration of various immune cells causes tumour immune microenvironment (TIME) heterogeneity, and results in different therapeutic effects. Accumulating evidence showed that DNA methylation plays a crucial role in remodelling TIME and is associated with the response towards immune checkpoint inhibitors (ICIs). During carcinogenesis, DNA methylation profoundly changes, specifically, there is a global loss of DNA methylation and increased DNA methylation at the promoters of suppressor genes. Immune cell differentiation is disturbed, and exclusion of immune cells from the TME occurs at least in part due to DNA methylation reprogramming. Therefore, pharmaceutical interventions targeting DNA methylation are promising. DNA methyltransferase inhibitors (DNMTis) enhance antitumor immunity by inducing transcription of transposable elements and consequent viral mimicry. DNMTis upregulate the expression of tumour antigens, mediate immune cells recruitment and reactivate exhausted immune cells. In preclinical studies, DNMTis have shown synergistic effect when combined with immunotherapies, suggesting new strategies to treat refractory solid tumours.

Examined lymph node numbers influence prognosis in rectal cancer treated with neoadjuvant therapy.

Background: The number of lymph nodes examined (LNe) is often insufficient in patients with rectal cancer (RC) treated with neoadjuvant therapy; however, its prognostic value remains controversial. Thus, we retrospectively explored whether LNe had an influence on staging and prognosis and investigated whether there was a cut-off value for better prognosis in patients with RC treated with neoadjuvant therapy. Methods: Data were collected from seven prospective hospital databases in China from July 2002 to May 2018. Binary logistic regression models were used to predict lymph node metastasis. The cut-off value for LNe was determined using X-tile 3.6.1. Survival outcomes and risk factors were analyzed using the log-rank test and Cox regression model. Results: A total of 482 patients were included, of whom 459 had complete overall survival (OS) information. Using the percentile method, the total number of lymph nodes examined (TLNe) was 14-16 (40th-60th percentile), and the proportion of patients with lymph node metastasis reached a maximum of 48.1%. Cox multivariate analysis showed that the odds ratio (OR) remained the highest when TLNe was 14-16 (OR = 3.379, P = 0.003). The 3-year and 5-year OS were 85.4% and 77.8%, respectively. Negative lymph nodes examined (NLNe) of ≤6 was an independent risk factor for 3-year and 5-year OS (3-year OS 71.1% vs. 85.9%, P = 0.004; 5-year OS 66.3% vs. 74.3%, P = 0.035). Subgroup analysis for patients with ypN + showed that higher 3-year and 5-year OS were achieved when the TLNe was >10, 78.8% vs. 54.0% (P = 0.005), and 60.8% vs. 36.0% (P = 0.012), respectively. Patients with ypN0M0 had a higher 5-year OS when the TLNe was >19 (P = 0.055). Conclusion: The TLNe and NLNe influenced the staging accuracy and demonstrated prognostic value in patients with RC treated with neoadjuvant therapy.

Parallel single-cell and bulk transcriptome analyses reveal key features of the gastric tumor microenvironment.

BACKGROUND: The tumor microenvironment (TME) has been shown to strongly influence treatment outcome for cancer patients in various indications and to influence the overall survival. However, the cells forming the TME in gastric cancer have not been extensively characterized. RESULTS: We combine bulk and single-cell RNA sequencing from tumors and matched normal tissue of 24 treatment-naïve GC patients to better understand which cell types and transcriptional programs are associated with malignant transformation of the stomach. Clustering 96,623 cells of non-epithelial origin reveals 81 well-defined TME cell types. We find that activated fibroblasts and endothelial cells are most prominently overrepresented in tumors. Intercellular network reconstruction and survival analysis of an independent cohort imply the importance of these cell types together with immunosuppressive myeloid cell subsets and regulatory T cells in establishing an immunosuppressive microenvironment that correlates with worsened prognosis and lack of response in anti-PD1-treated patients. In contrast, we find a subset of IFNγ activated T cells and HLA-II expressing macrophages that are linked to treatment response and increased overall survival. CONCLUSIONS: Our gastric cancer single-cell TME compendium together with the matched bulk transcriptome data provides a unique resource for the identification of new potential biomarkers for patient stratification. This study helps further to elucidate the mechanism of gastric cancer and provides insights for therapy.

Five-Year Prognosis of Complete Mesocolic Excision in Patients with Colon Cancer: A Prospective, Nonrandomized, Double-Blind Controlled Trial.

BACKGROUND: Previous studies on how complete mesocolic excision (CME) affects prognosis indicate fundamental limitations that prevent the procedure from being completely accepted in practice. This study evaluated 5-year survival in colon cancer patients who underwent CME in a strict quality-controlled trial. STUDY DESIGN: A prospective, nonrandomized, double-blind, controlled trial recruited patients who underwent open radical resection for colon cancer between November 2012 and November 2017. Third-party experts evaluated whether patients had undergone mesocolic dissection and/or central ligation by looking at photographs of both surgical field and specimen, and then divided patients into CME and non-CME (NCME) groups. The primary outcome was the 5-year local recurrence-free survival rate. Clinicopathological and follow-up data were recorded. RESULTS: There were 261 patients with a median follow-up time of 57 months assigned to the CME group, and 129 patients with a median follow-up time of 59 months were assigned to the NCME group. The 5-year local recurrence-free survival rate of patients with Union Internationale Contre le Cancer stage I to III cancer did not differ significantly between the groups. For stage I to III cancer and stage III cancer, the absolute risk reduction of 5-year cumulative death and disease progression after CME were 9.1% (95% CI 1% to 17%; p = 0.033) and 16.1% (95% CI 1% to 31%; p = 0.040), respectively. Meanwhile, CME also could reduce 14% 5-year cumulative incidence recurrence for Union Internationale Contre le Cancer stage III cancer compared with NCME (CME, 27.3% vs NCME, 41.3%; p = 0.042) after adjusting for the effect of non-cancer-related death. CONCLUSIONS: CME should be considered as a standard surgical procedure in affected patients.

Cuproptosis patterns and tumor immune infiltration characterization in colorectal cancer.

Faced with the high heterogeneity and poor prognosis of colorectal cancer (CRC), this study sought to find new predictive prognostic strategies to improve the situation. Cuproptosis is a novel cell death mechanism that relies on copper regulation. However, the role of cuproptosis-related gene (CRG) in CRC remains to be elucidated. In this study, we comprehensively assessed the CRG landscape in CRC based on The Cancer Genome Atlas (TCGA). We identified differential expression and genetic alterations of CRG in CRC. CRG is highly correlated with initiation, progression, prognosis, and immune infiltration of CRC. We construct a risk score signature containing 3 CRGs based on LASSO. We explored the correlation of CRG-Score with clinicopathological features of CRC. Age, stage, and CRG-Score were integrated to construct a nomogram. The nomogram has robust predictive performance. We also understand the correlation of CRG-Score with CRC immune landscape. CRG-Score can effectively predict the immune landscape of CRC patients. Low-risk CRC patients have greater immunogenicity and higher immune checkpoint expression. Low-risk CRC patients may be better candidates for immunotherapy. At the same time, we also predicted more sensitive drugs in the high-risk CRC patients. In conclusion, the CRG risk score signature is a strong prognostic marker and may help provide new insights into the treatment of individuals with CRC.

N6-methyladenosine demethylase ALKBH5 suppresses colorectal cancer progression potentially by decreasing PHF20 mRNA methylation.

BACKGROUND: As the most widespread mRNAs modification, N6-methyladenosine (m6 A) is dynamically and reversibly modulated by methyltransferases and demethylases. ALKBH5 is a major demethylase, and plays vital roles in the progression of cancers. However, the role and mechanisms of ALKBH5 in colorectal cancer (CRC) is unclear. RESULTS: Herein, we discovered that in CRC, downregulated ALKBH5 was closely related to poor prognosis of CRC patients. Functionally, our results demonstrated that knockdown of ALKBH5 enhanced the proliferation, migration and invasion of LOVO and RKO in vitro, while overexpression of ALKBH5 inhibited the functions of these cells. The results also demonstrated that knockdown of ALKBH5 promoted subcutaneous tumorigenesis of LOVO in vivo, while overexpression of ALKBH5 suppressed this ability. Mechanistically, results from joint analyses of MeRIP-seq and RNA-seq indicated that PHF20 mRNA was a key molecule that was regulated by ALKBH5-mediated m6 A modification. Further experiments indicated that ALKBH5 may inhibit stability of PHF20 mRNA by removing the m6 A modification of PHF20 mRNA 3'UTR. CONCLUSIONS: ALKBH5 suppresses CRC progression by decreasing PHF20 mRNA methylation. ALKBH5-mediated m6 A modification of PHF20 mRNA can serve as a hopeful strategy for the intervention and treatment of CRC.