Chemotherapy combined with or without targeted therapy is the fundamental treatment for metastatic colorectal cancer (mCRC). Due to the adverse effects of chemotherapeutic drugs and the biological ...characteristics of the tumor cells, it is difficult to make breakthroughs in traditional strategies. The immune checkpoint blockades (ICB) therapy has made significant progress in the treatment of advanced malignant tumors, and patients who benefit from this therapy may obtain a long-lasting response. Unfortunately, immunotherapy is only effective in a limited number of patients with microsatellite instability--high (MSI-H), and segment initial responders can subsequently develop acquired resistance. From September 4, 2014, the first anti-PD-1/PD-L1 drug Pembrolizumab was approved by the FDA for the second-line treatment of advanced malignant melanoma. Subsequently, it was approved for mCRC second-line treatment in 2017. Immunotherapy has rapidly developed in the past 7 years. The in-depth research of the ICB treatment indicated that the mechanism of colorectal cancer immune-resistance has become gradually clear, and new predictive biomarkers are constantly emerging. Clinical trials examining the effect of immune checkpoints are actively carried out, in order to produce long-lasting effects for mCRC patients. This review summarizes the treatment strategies for mCRC patients, discusses the mechanism and application of ICB in mCRC treatment, outlines the potential markers of the ICB efficacy, lists the key results of the clinical trials, and collects the recent basic research results, in order to provide a theoretical basis and practical direction for immunotherapy strategies. Keywords: Metastatic colorectal cancer, Immune checkpoint blockade, Immunotherapy, Biomarkers, Immune desert, Microsatellite instability, Precision medicine
Genetic variants and lifestyle factors have been associated with gastric cancer risk, but the extent to which an increased genetic risk can be offset by a healthy lifestyle remains unknown. We aimed ...to establish a genetic risk model for gastric cancer and assess the benefits of adhering to a healthy lifestyle in individuals with a high genetic risk.
In this meta-analysis and prospective cohort study, we first did a fixed-effects meta-analysis of the association between genetic variants and gastric cancer in six independent genome-wide association studies (GWAS) with a case-control study design. These GWAS comprised 21 168 Han Chinese individuals, of whom 10 254 had gastric cancer and 10 914 geographically matched controls did not. Using summary statistics from the meta-analysis, we constructed five polygenic risk scores in a range of thresholds (p=5 × 10−4 p=5 × 10−5 p=5 × 10−6 p=5 × 10−7, and p=5 × 10−8) for gastric cancer. We then applied these scores to an independent, prospective, nationwide cohort of 100 220 individuals from the China Kadoorie Biobank (CKB), with more than 10 years of follow-up. The relative and absolute risk of incident gastric cancer associated with healthy lifestyle factors (defined as not smoking, never consuming alcohol, the low consumption of preserved foods, and the frequent intake of fresh fruits and vegetables), was assessed and stratified by genetic risk (low quintile 1 of the polygenic risk score, intermediate quintile 2–4 of the polygenic risk score, and high quintile 5 of the polygenic risk score). Individuals with a favourable lifestyle were considered as those who adopted all four healthy lifestyle factors, those with an intermediate lifestyle adopted two or three factors, and those with an unfavourable lifestyle adopted none or one factor.
The polygenic risk score derived from 112 single-nucleotide polymorphisms (p<5 × 10−5) showed the strongest association with gastric cancer risk (p=7·56 × 10−10). When this polygenic risk score was applied to the CKB cohort, we found that there was a significant increase in the relative risk of incident gastric cancer across the quintiles of the polygenic risk score (ptrend<0·0001). Compared with individuals who had a low genetic risk, those with an intermediate genetic risk (hazard ratio HR 1·54 95% CI 1·22–1·94, p=2·67 × 10−4) and a high genetic risk (2·08 1·61–2·69, p<0·0001) had a greater risk of gastric cancer. A similar increase in the relative risk of incident gastric cancer was observed across the lifestyle categories (ptrend<0·0001), with a higher risk of gastric cancer in those with an unfavourable lifestyle than those with a favourable lifestyle (2·03 1·46–2·83, p<0·0001). Participants with a high genetic risk and a favourable lifestyle had a lower risk of gastric cancer than those with a high genetic risk and an unfavourable lifestyle (0·53 0·29–0·99, p=0·048), with an absolute risk reduction of 1·12% (95% CI 0·62–1·56).
Chinese individuals at an increased risk of incident gastric cancer could be identified by use of our newly developed polygenic risk score. Compared with individuals at a high genetic risk who adopt an unhealthy lifestyle, those who adopt a healthy lifestyle could substantially reduce their risk of incident gastric cancer.
National Key R&D Program of China, National Natural Science Foundation of China, 333 High-Level Talents Cultivation Project of Jiangsu Province, and China Postdoctoral Science Foundation.
Background
To evaluate the clinical implications of non-biological factors (NBFs) with colorectal cancer (CRC) patients younger than 45 years.
Methods
In the present study, we have conducted Cox ...proportional hazard regression analyses to evaluate the prognosis of different prognostic factors, the hazard ratios (HRs) were shown with 95% confidence intervals (CIs). Kaplan–Meier method was utilized to compare the prognostic value of different factors with the log-rank test. NBF score was established according to the result of multivariate Cox analyses.
Results
In total, 15129 patients before 45 years with known NBFs were identified from the SEER database. Only county-level median household income, marital status and insurance status were NBFs that significantly corelated with the cause specifical survival in CRC patients aged less than 45 years old (P < 0.05). Stage NBF 1 showed 50.5% increased risk of CRC-specific mortality (HR = 1.505, 95% CI = 1.411-1.606, P < 0.001). Stage NBF 0 patients were associated with significantly increased CRC-specific survival (CCSS) when compared with the stage NBF 1 patients in different AJCC TNM stages.
Conclusions
NBF stage (defined by county-level median household income, marital status and insurance status) was strongly related to the prognosis of CRC patients. NBFs should arouse enough attention of us in clinical practice of patients younger than 45 years.
The shortage of healthcare workers is becoming a serious global problem. The underlying reasons may be specific to the healthcare system in each country. Over the past decade, medicine has become an ...increasingly unpopular profession in China due to the heavy workload, long-term training, and inherent risks. The ongoing COVID-19 pandemic has placed the life-saving roles of healthcare professionals under the spotlight. This public health crisis may have a profound impact on career choices in Chinese population.
We conducted a questionnaire-based online survey among 21,085 senior high school students and 21,009 parents from 24 provinces (or municipalities) of China. We investigated the change of interest in medical study due to the outbreak of COVID-19 and the potential motivational factors based on the expectancy-value theory framework. Pearson correlation analysis was used to assess the correlation of static or dynamic interest in medical career pursuit with the reported number of COVID-19 cases. Logistic regression model was adopted to analyze the main factors associated with students' choices.
We observed an increased preference for medical study post the outbreak of COVID-19 in both students (17.5 to 29.6%) and parents (37.1 to 47.3%). Attainment value was found to be the main reason for the choice among students, with the contribution to society rated as the top motivation. On the other hand, the predominant demotivation in high school students was lack of interest, followed by concerns regarding violence against doctors, heavy workload, long-term training and heavy responsibility as a doctor. Additionally, students who were female, in the resit of final year, had highly educated parents and outside of Hubei province were significantly associated with a keen interest in pursuing medical study.
This is the first multi-center cross-sectional study exploring the positive change and motivations of students' preferences in medical study due to the outbreak of COVID-19. Our results may help medical educators, researchers and policymakers to restructure medical education to make it more appealing to high school students, particularly, to develop a more supportive social and working environment for medical professionals to maintain the observed enhanced enthusiasm.
•Acute postnatal exposure to VPA induced autism-like behaviors.•VPA could affect transcriptional and splicing events genome-wide.•Dysregulated genes are associated with neurological diseases and ...neural system development.
Gene-environmental interaction could be the major cause of autism. The aim of the current study is to detect the effects of valproic acid on gene expression profiles and alternatively spliced genes in the prefrontal cortex in rat models of autism. Female rats received a single intraperitoneal injection of 600 mg/kg valproic acid at day 12.5 post-conception, and controls were injected with saline. Only male offspring were employed in the current study. RNA sequencing was used to investigate transcriptome in the prefrontal cortex of VPA-exposed rats. There were 3228 differently expressed genes and 637 alternative spliced genes, in VPA rats compared to controls. Pathways enrichment among the differently expressed genes and alternatively spliced genes were associated with neurological diseases and neural system development. The results implied VPA affected transcriptional and splicing events genome-wide and the transcriptional and splicing events may be associated with the autistic behaviors of VPA rats.
Genome-wide association studies have revealed an association between coronary heart disease (CHD) and genetic variation on chromosome 13q34, with the lead single nucleotide polymorphism rs4773144 ...residing in the COL4A2 gene in this genomic region. We investigated the functional effects of this genetic variant. Analyses of primary cultures of vascular smooth muscle cells (SMCs) and endothelial cells (ECs) from different individuals showed a difference between rs4773144 genotypes in COL4A2 and COL4A1 expression levels, being lowest in the G/G genotype, intermediate in A/G and highest in A/A. Chromatin immunoprecipitation followed by allelic imbalance assays of primary cultures of SMCs and ECs that were of the A/G genotype revealed that the G allele had lower transcriptional activity than the A allele. Electrophoretic mobility shift assays and luciferase reporter gene assays showed that a short DNA sequence encompassing the rs4773144 site interacted with a nuclear protein, with lower efficiency for the G allele, and that the G allele sequence had lower activity in driving reporter gene expression. Analyses of cultured SMCs from different individuals demonstrated that cells of the G/G genotype had higher apoptosis rates. Immunohistochemical and histological examinations of ex vivo atherosclerotic coronary arteries from different individuals disclosed that atherosclerotic plaques with the G/G genotype had lower collagen IV abundance and thinner fibrous cap, a hallmark of unstable, rupture-prone plaques. A study of a cohort of patients with angiographically documented coronary artery disease showed that patients of the G/G genotype had higher rates of myocardial infarction, a phenotype often caused by plaque rupture. These results indicate that the CHD-related genetic variant at the COL4A2 locus affects COL4A2/COL4A1 expression, SMC survival, and atherosclerotic plaque stability, providing a mechanistic explanation for the association between the genetic variant and CHD risk.
We previously reported that some single nucleotide polymorphisms (SNPs) of candidate genes involved in the MTOR complex1 (MTORC1) were associated with risk of gastric cancer (GCa). In the present ...study, we further evaluated associations of eight potentially functional SNPs of MTOR, MLST8 and RPTOR with survival of 1002 GCa patients and also investigated molecular mechanisms underlying such associations. Specifically, we found that the MTOR rs2536 C allele at the microRNA binding site was independently associated with a 26% reduction of death risk (HR = 0.74, 95% CI = 0.57–0.96, p = 0.022). The results remained noteworthy with a prior false positive probability of 0.1. Genotype–phenotype correlation analysis in 144 patients’ adjacent normal gastric tissue samples revealed that the MTOR expression levels were lower in rs2536 TC/CC carriers than that in wild‐type TT carriers (p = 0.043). Dual luciferase assays revealed that the rs2536 C allele had a higher binding affinity to microRNA‐150, leading to a decreased transcriptional activity of MTOR, compared to the rs2536 T allele. Further functional analysis revealed that MTOR knockdown by small interference RNA impaired proliferation, migration, and invasion ability in GCa cell lines. In conclusion, The MTOR rs2536 T > C change may be a biomarker for survival of Chinese GCa patients, likely by modulating microRNA‐induced gene expression silencing. Additional studies are needed to validate our findings.
What's new?
While MTORC1 is known to play an important role in the development of gastric cancer (GCa), its role in GCa progression remains unclear. This study of 1002 Chinese GCa patients demonstrated for the first time that the MTOR rs2536 T > C change predicted better overall survival. Functional studies showed that the 3′UTR of MTOR with rs2536 C had a better binding affinity to miRNA‐150, leading to down‐regulated MTOR expression and a less aggressive phenotype of GCa cells. The MTOR rs2536 T > C change may thus be a biomarker for survival of Chinese GCa patients, likely acting by modulating microRNA‐induced gene expression silencing.
Background
Circular RNAs (circRNAs) generated by back‐splicing of precursor mRNAs (pre‐mRNAs) are often aberrantly expressed in cancer cells. Accumulating evidence has revealed that circRNAs play a ...critical role in the progression of several cancers, including colorectal cancer (CRC). However, the current understandings of the emerging functions of circRNAs in CRC lipid metabolism and the underlying molecular mechanisms are still limited. Here, we aimed to explore the role of circCAPRIN1 in regulating CRC lipid metabolism and tumorigenesis.
Methods
circRNA microarray was performed with three pairs of tumor and non‐tumor tissues from CRC patients. The expression of circRNAs were determined by quantitative PCR (qPCR) and in situ hybridization (ISH). The endogenous levels of circRNAs in CRC cells were manipulated by transfection with lentiviruses overexpressing or silencing circRNAs. The regulatory roles of circRNAs in the occurrence of CRC were investigated both in vitro and in vivo using gene expression array, RNA pull‐down/mass spectrometry, RNA immunoprecipitation assay, luciferase reporter assay, chromatin immunoprecipitation analysis, and fluorescence in situ hybridization (FISH).
Results
Among circRNAs, circCAPRIN1 was most significantly upregulated in CRC tissue specimens. circCAPRIN1 expression was positively correlated with the clinical stage and unfavorable prognosis of CRC patients. Downregulation of circCAPRIN1 suppressed proliferation, migration, and epithelial‐mesenchymal transition of CRC cells, while circCAPRIN1 overexpression had opposite effects. RNA sequencing and gene ontology analysis indicated that circCAPRIN1 upregulated the expressions of genes involved in CRC lipid metabolism. Moreover, circCAPRIN1 promoted lipid synthesis by enhancing Acetyl‐CoA carboxylase 1 (ACC1) expression. Further mechanistic assays demonstrated that circCAPRIN1 directly bound signal transducer and activator of transcription 2 (STAT2) to activate ACC1 transcription, thus regulating lipid metabolism and facilitating CRC tumorigenesis.
Conclusions
These findings revealed the oncogenic role and mechanism of circCAPRIN1 in CRC. circCAPRIN1 interacted with STAT2 to promote CRC tumor progression and lipid synthesis by enhancing the expression of ACC1. circCAPRIN1 may be considered as a novel potential diagnostic and therapeutic target for CRC patients.
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