Single-Cell Analyses Inform Mechanisms of Myeloid-Targeted Therapies in Colon Cancer.

Single-cell RNA sequencing (scRNA-seq) is a powerful tool for defining cellular diversity in tumors, but its application toward dissecting mechanisms underlying immune-modulating therapies is scarce. We performed scRNA-seq analyses on immune and stromal populations from colorectal cancer patients, identifying specific macrophage and conventional dendritic cell (cDC) subsets as key mediators of cellular cross-talk in the tumor microenvironment. Defining comparable myeloid populations in mouse tumors enabled characterization of their response to myeloid-targeted immunotherapy. Treatment with anti-CSF1R preferentially depleted macrophages with an inflammatory signature but spared macrophage populations that in mouse and human expresses pro-angiogenic/tumorigenic genes. Treatment with a CD40 agonist antibody preferentially activated a cDC population and increased Bhlhe40+ Th1-like cells and CD8+ memory T cells. Our comprehensive analysis of key myeloid subsets in human and mouse identifies critical cellular interactions regulating tumor immunity and defines mechanisms underlying myeloid-targeted immunotherapies currently undergoing clinical testing.

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.

ABHD6 suppresses colorectal cancer progression via AKT signaling pathway.

Colorectal cancer (CRC) continues to be a prevalent malignancy, posing a significant risk to human health. The involvement of alpha/beta hydrolase domain 6 (ABHD6), a serine hydrolase family member, in CRC development was suggested by our analysis of clinical data. However, the role of ABHD6 in CRC remains unclear. This study seeks to elucidate the clinical relevance, biological function, and potential molecular mechanisms of ABHD6 in CRC. We investigated the role of ABHD6 in clinical settings, conducting proliferation, migration, and cell cycle assays. To determine the influence of ABHD6 expression levels on Oxaliplatin sensitivity, we also performed apoptosis assays. RNA sequencing and KEGG analysis were utilized to uncover the potential molecular mechanisms of ABHD6. Furthermore, we validated its expression levels using Western blot and reactive oxygen species (ROS) detection assays. Our results demonstrated that ABHD6 expression in CRC tissues was notably lower compared to adjacent normal tissues. This low expression correlated with a poorer prognosis for CRC patients. Moreover, ABHD6 overexpression impeded CRC cell proliferation and migration while inducing G0/G1 cell cycle arrest. In vivo experiments revealed that downregulation of ABHD6 resulted in an increase in tumor weight and volume. Mechanistically, ABHD6 overexpression inhibited the activation of the AKT signaling pathway and decreased ROS levels in CRC cells, suggesting the role of ABHD6 in CRC progression via the AKT signaling pathway. Our findings demonstrate that ABHD6 functions as a tumor suppressor, primarily by inhibiting the AKT signaling pathway. This role establishes ABHD6 as a promising prognostic biomarker and a potential therapeutic target for CRC patients.

Overall survival prediction of gastric cancer using the gene signature of CT-detected extramural venous invasion combined with M2 macrophages infiltration.

BACKGROUND: CT-detected Extramural venous invasion (EMVI) is known as an independent risk factor for distant metastasis in patients with advanced gastric cancer (GC). However, the molecular basis is not clear. In colorectal cancer, M2 macrophages plays a vital role in determining EMVI. This study aimed to investigate the relationship between CT-detected EMVI and the M2 macrophages as well as prognosis predictionusing a radiogenomic approach. METHOD: We utilized EMVI-related genes (from mRNA sequencing of 13 GC samples correlated with EMVI score by spearman analysis, P < 0.01) to overlap the co-expression genes of WGCNA module and M2 macrophages related genes (from mRNA data of 371 GC patients in TCGA database), generating a total of 136 genes. An EMVI-M2-prognosis-related hub gene signature was constructed by COX and least absolute shrinkage and selection operator (LASSO) analysis from a training cohort TCGA database (n = 371) and validated it in a validation cohort from GEO database (n = 357). High- and low-risk groups were divided by hub gene (EGFLAM and GNG11) signature-derived risk scores. We assessed its predictive ability through Kaplan-Meier (K-M) curve and COX analysis. Furthermore, we utilized ESTIMATE to detect tumor mutation burden (TMB) and evaluate sensitivity to immune checkpoint inhibitors (ICIs). Expression of hub genes was tested using western blotting and immunohistochemistry (IHC) analysis. RESULTS: The overall survival (OS) was significantly reduced in the high-risk group (Training/Validation: AUC = 0.701/0.620; P < 0.001/0.003). Furthermore, the risk score was identified as an independent predictor of OS in multivariate COX regression analyses (Training/Validation: HR = 1.909/1.928; 95% CI: 1.225-2.974/1.308-2.844). The low-risk group exhibited significantly higher TMB levels (P = 1.6e- 07) and greater sensitivity to ICIs. Significant higher expression of hub-genes was identified on multiple GC cell lines and original samples. Hub-genes knockdown in gastric cancer cell lines inhibited their proliferation, metastatic and invasive capacity to varying degrees. In vivo experiments indicate that EGFLAM, as one of the hub genes, its high expression can serve as a biomarker for low response to immunotherapy. CONCLUSION: Our study demonstrated EMVI-M2 gene signature could effectively predict the prognosis of GC tissue, reflecting the relationship between EMVI and M2 macrophages.

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.

Lineage tracking reveals dynamic relationships of T cells in colorectal cancer.

T cells are key elements of cancer immunotherapy1 but certain fundamental properties, such as the development and migration of T cells within tumours, remain unknown. The enormous T cell receptor (TCR) repertoire, which is required for the recognition of foreign and self-antigens2, could serve as lineage tags to track these T cells in tumours3. Here we obtained transcriptomes of 11,138 single T cells from 12 patients with colorectal cancer, and developed single T cell analysis by RNA sequencing and TCR tracking (STARTRAC) indices to quantitatively analyse the dynamic relationships among 20 identified T cell subsets with distinct functions and clonalities. Although both CD8+ effector and 'exhausted' T cells exhibited high clonal expansion, they were independently connected with tumour-resident CD8+ effector memory cells, implicating a TCR-based fate decision. Of the CD4+ T cells, most tumour-infiltrating T regulatory (Treg) cells showed clonal exclusivity, whereas certain Treg cell clones were developmentally linked to several T helper (TH) cell clones. Notably, we identified two IFNG+ TH1-like cell clusters in tumours that were associated with distinct IFNγ-regulating transcription factors -the GZMK+ effector memory T cells, which were associated with EOMES and RUNX3, and CXCL13+BHLHE40+ TH1-like cell clusters, which were associated with BHLHE40. Only CXCL13+BHLHE40+ TH1-like cells were preferentially enriched in patients with microsatellite-instable tumours, and this might explain their favourable responses to immune-checkpoint blockade. Furthermore, IGFLR1 was highly expressed in both CXCL13+BHLHE40+ TH1-like cells and CD8+ exhausted T cells and possessed co-stimulatory functions. Our integrated STARTRAC analyses provide a powerful approach to dissect the T cell properties in colorectal cancer comprehensively, and could provide insights into the dynamic relationships of T cells in other cancers.

Therapeutic potentials of FexMoyS-PEG nanoparticles in colorectal cancer: a multimodal approach via ROS-ferroptosis-glycolysis regulation.

Improving cancer therapy by targeting the adverse tumor microenvironment (TME) rather than the cancer cells presents a novel and potentially effective strategy. In this study, we introduced FexMoyS nanoparticles (NPs), which act as sequential bioreactors to manipulate the TME. FexMoyS NPs were synthesized using thermal decomposition and modified with polyethylene glycol (PEG). Their morphology, chemical composition, and photothermal properties were characterized. The capability to produce ROS and deplete GSH was evaluated. Effects on CRC cells, including cell viability, apoptosis, and glycolysis, were tested through various in vitro assays. In vivo efficacy was determined using CRC-bearing mouse models and patient-derived xenograft (PDX) models. The impact on the MAPK signaling pathway and tumor metabolism was also examined. The FexMoyS NPs showed efficient catalytic activity, leading to increased ROS production and GSH depletion, inducing ferroptosis, and suppressing glycolysis in CRC cells. In vivo, the NPs significantly inhibited tumor growth, particularly when combined with NIR light therapy, indicating a synergistic effect of photothermal therapy and chemodynamic therapy. Biosafety assessments revealed no significant toxicity in treated mice. RNA sequencing suggested that the NPs impact metabolism and potentially immune processes within CRC cells. FexMoyS NPs present a promising multifaceted approach for CRC treatment, effectively targeting tumor cells while maintaining biosafety. The nanoparticles exhibit potential for clinical translation, offering a new avenue for cancer therapy.

Conformal thyroidectomy is a feasible option in papillary thyroid microcarcinoma: a retrospective cohort study with 10-year follow-up results.

BACKGROUND: In recent years, there has been an increasing prevalence of patients with papillary thyroid microcarcinoma (PTMC) without lymph node involvement in medical centers worldwide. For patients who are unable to undergo active surveillance (AS) and are afraid of postoperative complications, conformal thyroidectomy may be a suitable option to ensure both preservation of function and complete removal of the tumor. METHODS: The patients in the cohort during 2010 to 2015 were retrospectively enrolled strictly following the inclusion and exclusion criteria. The observation and control groups were defined based on the surgical approach, with patients in the observation group undergoing conformal thyroidectomy and patients in the control group undergoing lobectomy. Event-free survival (EFS), the interval from initial surgery to the detection of recurrent or metastatic disease, was defined as the primary observation endpoint. RESULTS: A total of 319 patients were included in the study, with 124 patients undergoing conformal thyroidectomy and 195 patients undergoing lobectomy. When compared to lobectomy, conformal thyroidectomy demonstrated reduced hospital stays, shorter operative times, and lower rates of vocal cord paralysis and hypoparathyroidism. Furthermore, the mean bleeding volume during the operation and the rate of permanent hypothyroidism were also lower in the conformal thyroidectomy group than in the lobectomy group. However, there was no statistically significant difference observed in the 5- and 10-year EFS between the two groups. CONCLUSIONS: Conformal thyroidectomy had advantages in perioperative management and short-term complication rates, with an EFS that was not inferior to that of lobectomy. Thus, conformal thyroidectomy is a feasible option for low-risk PTMC patients.

Machine learning-based prediction models affecting the recovery of postoperative bowel function for patients undergoing colorectal surgeries.

PURPOSE: The debate surrounding factors influencing postoperative flatus and defecation in patients undergoing colorectal resection prompted this study. Our objective was to identify independent risk factors and develop prediction models for postoperative bowel function in patients undergoing colorectal surgeries. METHODS: A retrospective analysis of medical records was conducted for patients who undergoing colorectal surgeries at Peking University People's Hospital from January 2015 to October 2021. Machine learning algorithms were employed to identify risk factors and construct prediction models for the time of the first postoperative flatus and defecation. The prediction models were evaluated using sensitivity, specificity, the Youden index, and the area under the receiver operating characteristic curve (AUC) through logistic regression, random forest, Naïve Bayes, and extreme gradient boosting algorithms. RESULTS: The study included 1358 patients for postoperative flatus timing analysis and 1430 patients for postoperative defecation timing analysis between January 2015 and December 2020 as part of the training phase. Additionally, a validation set comprised 200 patients who undergoing colorectal surgeries from January to October 2021. The logistic regression prediction model exhibited the highest AUC (0.78) for predicting the timing of the first postoperative flatus. Identified independent risk factors influencing the time of first postoperative flatus were Age (p < 0.01), oral laxatives for bowel preparation (p = 0.01), probiotics (p = 0.02), oral antibiotics for bowel preparation (p = 0.02), duration of operation (p = 0.02), postoperative fortified antibiotics (p = 0.02), and time of first postoperative feeding (p < 0.01). Furthermore, logistic regression achieved an AUC of 0.72 for predicting the time of first postoperative defecation, with age (p < 0.01), oral antibiotics for bowel preparation (p = 0.01), probiotics (p = 0.01), and time of first postoperative feeding (p < 0.01) identified as independent risk factors. CONCLUSIONS: The study suggests that he use of probiotics and early recovery of diet may enhance the recovery of bowel function in patients undergoing colorectal surgeries. Among the various analytical methods used, logistic regression emerged as the most effective approach for predicting the timing of the first postoperative flatus and defecation in this patient population.

Incidence, risk factors, and outcomes of the transition of HIPEC-induced acute kidney injury to acute kidney disease: a retrospective study.

BACKGROUND: Acute kidney injury (AKI) is recognized as a common complication following cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Characterized by prolonged renal function impairment, acute kidney disease (AKD) is associated with a higher risk of chronic kidney disease (CKD) and mortality. METHODS: From January 2018 to December 2021, 158 patients undergoing CRS-HIPEC were retrospectively reviewed. Patients were separated into non-AKI, AKI, and AKD cohorts. Laboratory parameters and perioperative features were gathered to evaluate risk factors for both HIPEC-induced AKI and AKD, with the 90-day prognosis of AKD patients. RESULTS: AKI developed in 21.5% of patients undergoing CRS-HIPEC, while 13.3% progressed to AKD. The multivariate analysis identified that ascites, GRAN%, estimated glomerular filtration rate (eGFR), and intraoperative (IO) hypotension duration were associated with the development of HIPEC-induced AKI. Higher uric acid, lessened eGFR, and prolonged IO hypotension duration were more predominant in patients proceeding with AKD. The AKD cohort presented a higher risk of 30 days of in-hospital mortality (14.3%) and CKD progression (42.8%). CONCLUSIONS: Our study reveals a high incidence of AKI and AKI-to-AKD transition. Early identification of risk factors for HIPEC-induced AKD would assist clinicians in taking measures to mitigate the incidence.

China special issue on gastrointestinal tumors-Improved survival after multidisciplinary team decision for patients with advanced gastrointestinal cancer: A multicenter, noninterventional, controlled study.

Formal multidisciplinary team (MDT) discussions in clinical practice require time and space but have unclear survival benefits for advanced gastrointestinal cancer patients. Our study aimed to investigate the long-term survival of patients with advanced gastrointestinal cancer after MDT decision. From June 2017 to June 2019, continuous MDT discussions on advanced gastrointestinal cancer were conducted in 13 medical centers in China. MDT decisions and actual treatment received by patients were prospectively recorded. The primary endpoint was the difference in overall survival (OS) between patients in the MDT decision implementation and nonimplementation groups. The secondary endpoints included the implementation rate of MDT decisions and subgroup survival analysis. A total of 461 MDT decisions of 455 patients were included in our study. The implementation rate of MDT decisions was 85.7%. Previous treatment had an impact on MDT decision-making. The OS was 24.0 months and 17.0 months in the implementation and nonimplementation groups, respectively. The implementation of MDT decisions significantly reduced the risk of death in multivariate analyses (hazard ratio = 0.518; 95% confidence interval: 0.304-0.884, P = .016). Subgroup analysis showed a significant difference in survival of patients with colorectal cancer, but not in survival of patients with gastric cancer. The rate of secondary MDT discussion was only 5.6% among patients who the MDT decisions were discontinued due to changes in their condition. MDT discussion can prolong the OS of patients with advanced gastrointestinal cancer, especially those with colorectal cancer. Timely scheduling of the subsequent MDT discussion is necessary when the disease condition changes.

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.

Computed tomography-detected extramural venous invasion-related gene signature: a potential negative biomarker of immune checkpoint inhibitor treatment in patients with gastric cancer.

BACKGROUND: To investigate the association between computed tomography (CT)-detected extramural venous invasion (EMVI)-related genes and immunotherapy resistance and immune escape in patients with gastric cancer (GC). METHODS: Thirteen patients with pathologically proven locally advanced GC who had undergone preoperative abdominal contrast-enhanced CT and radical resection surgery were included in this study. Transcriptome sequencing was multidetector performed on the cancerous tissue obtained during surgery, and EMVI-related genes (P value for association < 0.001) were selected. A single-sample gene set enrichment analysis algorithm was also used to divide all GC samples (n = 377) in The Cancer Genome Atlas (TCGA) database into high and low EMVI-immune related groups based on immune-related differential genes. Cluster analysis was used to classify EMVI-immune-related genotypes, and survival among patients was validated in TCGA and Gene Expression Omnibus (GEO) cohorts. The EMVI scores were calculated using principal component analysis (PCA), and GC samples were divided into high and low EMVI score groups. Microsatellite instability (MSI) status, tumor mutation burden (TMB), response rate to immune checkpoint inhibitors (ICIs), immune escape were compared between the high and low EMVI score groups. Hub gene of the model in pan-cancer analysis was also performed. RESULTS: There were 17 EMVI-immune-related genes used for cluster analysis. PCA identified 8 genes (PCH17, SEMA6B, GJA4, CD34, ACVRL1, SOX17, CXCL12, DYSF) that were used to calculate EMVI scores. High EMVI score groups had lower MSI, TMB and response rate of ICIs, status but higher immune escape status. Among the 8 genes used for EMVI scores, CXCL12 and SOX17 were at the core of the protein-protein interaction (PPI) network and had a higher priority in pan-cancer analysis. Immunohistochemical analysis showed that the expression of CXCL12 and SOX17 was significantly higher in CT-detected EMVI-positive samples than in EMVI-negative samples (P < 0.0001). CONCLUSION: A CT-detected EMVI gene signature could be a potential negative biomarker for ICIs treatment, as the signature is negatively correlated with TMB, and MSI, resulting in poorer prognosis.

Risk stratification for 1- to 2-cm gastric gastrointestinal stromal tumors: visual assessment of CT and EUS high-risk features versus CT radiomics analysis.

OBJECTIVES: To investigate the ability of CT and endoscopic sonography (EUS) in predicting the malignant risk of 1-2-cm gastric gastrointestinal stromal tumors (gGISTs) and to clarify whether radiomics could be applied for risk stratification. METHODS: A total of 151 pathologically confirmed 1-2-cm gGISTs from seven institutions were identified by contrast-enhanced CT scans between January 2010 and March 2021. A detailed description of EUS morphological features was available for 73 gGISTs. The association between EUS or CT high-risk features and pathological malignant potential was evaluated. gGISTs were randomly divided into three groups to build the radiomics model, including 74 in the training cohort, 37 in validation cohort, and 40 in testing cohort. The ROIs covering the whole tumor volume were delineated on the CT images of the portal venous phase. The Pearson test and least absolute shrinkage and selection operator (LASSO) algorithm were used for feature selection, and the ROC curves were used to evaluate the model performance. RESULTS: The presence of EUS- and CT-based morphological high-risk features, including calcification, necrosis, intratumoral heterogeneity, irregular border, or surface ulceration, did not differ between very-low and intermediate risk 1-2-cm gGISTs (p > 0.05). The radiomics model consisting of five radiomics features showed favorable performance in discrimination of malignant 1-2-cm gGISTs, with the AUC of the training, validation, and testing cohort as 0.866, 0.812, and 0.766, respectively. CONCLUSIONS: Instead of CT- and EUS-based morphological high-risk features, the CT radiomics model could potentially be applied for preoperative risk stratification of 1-2-cm gGISTs. KEY POINTS: • The presence of EUS- and CT-based morphological high-risk factors, including calcification, necrosis, intratumoral heterogeneity, irregular border, or surface ulceration, did not correlate with the pathological malignant potential of 1-2-cm gGISTs. • The CT radiomics model could potentially be applied for preoperative risk stratification of 1-2-cm gGISTs.

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.

Lymph node metastasis in T1-2 colorectal cancer: a population-based study.

BACKGROUND: We performed this study to identify predictive factors for lymph node metastasis (LNM) and analyze the impact of LNM on the prognosis of patients with T1-2 colorectal cancer (CRC), with the intention of providing guidance for the treatment. METHODS: The Surveillance Epidemiology and End Result database was used to identify 20,492 patients diagnosed with T1-2 stage CRC between 2010 and 2019, who underwent surgery and lymph node evaluation and had complete prognostic information. Clinicopathological data of patients with T1-2 stage colorectal cancer treated with surgery at Peking University People's Hospital from 2017 to 2021 with complete clinical information were retrieved. We identify and confirm the risk factors for positive lymph node involvement, and the results of follow-up were analyzed. RESULTS: Age, preoperative carcinoembryonic antigen (CEA) level, perineural invasion, and primary tumor site were independent risk factors for LNM in T1-2 CRC based on the analysis of the SEER database, while tumor size and histology of mucinous carcinoma were also independent risk factors in T1 CRC. We then make the nomogram model for predicting LNM risk and showed an acceptable consistency and calibration capability. Survival analysis showed that LNM was an independent prognostic indicator of 5-year disease-specific survival (P = 0.013) and disease-free survival (P < 0.001) in patients with T1 and T2 CRC. CONCLUSION: Age, CEA level and primary tumor site should be taken into consideration before making the surgical decision in T1-2 CRC patients. The tumor size and histology of mucinous carcinoma also need to be thought about in T1 CRC. Conventional imaging tests do not appear to provide a precise assessment for this issue.

KLHL22 maintains PD-1 homeostasis and prevents excessive T cell suppression.

Aberrant programmed cell death protein 1 (PD-1) expression on the surface of T cells is known to inhibit T cell effector activity and to play a pivotal role in tumor immune escape; thus, maintaining an appropriate level of PD-1 expression is of great significance. We identified KLHL22, an adaptor of the Cul3-based E3 ligase, as a major PD-1-associated protein that mediates the degradation of PD-1 before its transport to the cell surface. KLHL22 deficiency leads to overaccumulation of PD-1, which represses the antitumor response of T cells and promotes tumor progression. Importantly, KLHL22 was markedly decreased in tumor-infiltrating T cells from colorectal cancer patients. Meanwhile, treatment with 5-fluorouracil (5-FU) could increase PD-1 expression by inhibiting the transcription of KLHL22. These findings reveal that KLHL22 plays a crucial role in preventing excessive T cell suppression by maintaining PD-1 expression homeostasis and suggest the therapeutic potential of 5-FU in combination with anti-PD-1 in colorectal cancer patients.

hsa_circ_0000231 Promotes colorectal cancer cell growth through upregulation of CCND2 by IGF2BP3/miR-375 dual pathway.

BACKGROUND: Circular RNAs (circRNAs) have emerged as vital regulators of the initiation and progression of diverse kinds of human cancers. In this study, we explored the role of hsa_circ_0000231 and its downstream pathway in CRC. METHODS: The expression profile of circRNAs in 5 pairs of CRC tissues and adjacent normal tissues were analyzed by Microarray. Quantitative real-time PCR and in situ hybridization and Base Scope Assay were used to determine the level and prognostic values of hsa_circ_0000231. Then, functional experiments in vitro and in vivo were performed to investigate the effects of hsa_circ_0000231 on cell proliferation. Mechanistically, fluorescent in situ hybridization, dual luciferase reporter assay, RNA pull-down and RNA immunoprecipitation experiments were performed to confirm the interaction between hsa_circ_0000231 and IGF2BP3 or has_miR-375. RESULTS: We acquired data through circRNA microarray profiles, showing that the expression of hsa_circ_0000231 was upregulated in CRC primary tissues compared to adjacent normal tissues, which was indicated poor prognosis of patients with CRC. Functional analysis indicated that inhibition of hsa_circ_0000231 in CRC cell lines could suppress CRC cell proliferation as well as tumorigenesis in vitro and in vivo. The mechanistic analysis showed that hsa_circ_0000231 might, on the one hand, act as a competing endogenous RNA of miR-375 to promote cyclin D2 (CCND2) and, on the other hand, bind to the IGF2BP3 protein to prevent CCND2 degradation. CONCLUSIONS: The findings suggested that hsa_circ_0000231 facilitated CRC progression by sponging miR-375 or binding to IGF2BP3 to modulate CCND2, implying that hsa_circ_0000231 might be a potential new diagnostic and therapeutic biomarker of CRC.

SIRT2-dependent IDH1 deacetylation inhibits colorectal cancer and liver metastases.

Protein lysine acetylation affects colorectal cancer (CRC) distant metastasis through multiple pathways. In a previous proteomics screen, we found that isocitrate dehydrogenase 1 (IDH1) is hyperacetylated in CRC primary tumors and liver metastases. Here, we further investigate the function of IDH1 hyperacetylation at lysine 224 in CRC progression. We find that IDH1 K224 deacetylation promotes its enzymatic activity and the production of α-KG, and we identify sirtuin-2 (SIRT2) as a major deacetylase for IDH1. SIRT2 overexpression significantly inhibits CRC cell proliferation, migration, and invasion. IDH1 acetylation is modulated in response to intracellular metabolite concentration and regulates cellular redox hemostasis. Moreover, IDH1 acetylation reversely regulates HIF1α-dependent SRC transcription which in turn controls CRC progression. Physiologically, our data indicate that IDH1 deacetylation represses CRC cell invasion and migration in vitro and in vivo, while the hyperacetylation of IDH1 on K224 is significantly correlated to distant metastasis and poor survival of colorectal cancer patients. In summary, our study uncovers a novel mechanism through which SIRT2-dependent IDH1 deacetylation regulates cellular metabolism and inhibits liver metastasis of colorectal cancer.

Establishment of the prediction model and biological mechanism exploration for secondary imatinib-resistant in gastrointestinal stromal tumor.

A gastrointestinal stromal tumor (GIST) is mostly driven by the auto-activated, mutant KIT receptor tyrosine kinase gene or by the platelet-derived growth factor receptor alpha. Inhibition of KIT-signaling is the primary molecular target therapy for GIST, which is performed by the drug imatinib clinically. However, more than half of advanced or metastatic GIST develop secondary resistance to imatinib within 2 years after initiation of treatment, and the mechanism of acquired imatinib-resistant in GIST remains unclear. Therefore, we designed the present study, and firstly analyzed the gene expression profile of imatinib-resistant and sensitive GIST from GEO DataSet and identified 44 differential expressed genes. Then, a model including nine genes with their expressed coefficients was identified as a risk score to predict imatinib-resistant GIST. Internal and external validation of the prediction model was performed through the ROC curve, and the area under the curve was 0.967 (95%CI 0.901-1.000) and 0.917 (95%CI 0.753-1.000), separately. Lastly, the effect of immune, m6A, pyroptosis, and ferroptosis-related genes on imatinib-resistant GIST was also assessed because DNA replication was the most enriched biological function of DEGs after functional annotation, pathway enrichment, and protein-protein interaction network analyses. In conclusion, the present study established a novel model to predict secondary imatinib-resistant GIST. Meanwhile, the bioinformatic mining results provided potential and promising targets for imatinib-resistant therapy.