Targeted re-sequencing identified rs3106189 at the 5' UTR of TAPBP and rs1052918 at the 3' UTR of TCF3 to be associated with the overall survival of colorectal cancer patients

PD-1 blockade plus COX inhibitors in dMMR metastatic colorectal cancer: Clinical, genomic, and immunologic analyses from the PCOX trial

BACKGROUND

Approximately 20% of patients with DNA mismatch repair deficiency (dMMR) metastatic colorectal cancer do not respond to anti-programmed death-1 (PD-1) ligand therapy, and baseline biomarkers of response are lacking.

METHODS

We conducted a phase 2 study to evaluate the efficacy of cyclooxygenase (COX) inhibitors in combination with anti-PD-1 therapy in patients with dMMR metastatic colorectal cancer. The primary endpoint was objective response rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate, duration of response, and safety.

FINDINGS

A total of 30 patients were enrolled, and the objective response rate was 73.3%, meeting the predefined endpoint of 68%. The median PFS and median OS were not reached at a median follow-up period of 50.8 months. Disease control was achieved in 28 patients (93.3%). The median duration of response was not reached. The combination was well tolerated. Multiomics analysis revealed that the antigen processing and presentation pathway was positively associated with treatment response and PFS. Higher TAPBP expression was predictive of better PFS (log-rank p = 0.003), and this prognostic significance was confirmed in an immunotherapy validation cohort.

CONCLUSIONS

Thus, COX inhibitors combined with PD-1 blockade may be effective and safe treatment options for patients with dMMR metastatic colorectal cancer, and TAPBP may serve as a biomarker for immune checkpoint inhibitor therapy (this study was registered at ClinicalTrials.gov: NCT03638297).

FUNDING

Funded by the National Natural Science Foundation of China (81974369) and the program of Guangdong Provincial Clinical Research Center for Digestive Diseases (2020B1111170004).

A genetic variant in the TAPBP gene enhances cervical cancer susceptibility by increasing m6A modification

Genetic variants can affect gene expression by altering the level of N6-methyladenosine (m6A) modifications. A better understanding of the association of these genetic variants with susceptibility to cervical cancer (CC) can promote advances in disease screening and treatment. Genome-wide identification of m6A-associated functional SNPs for CC was performed using the TCGA and JENGER databases, incorporating the data from RNA-seq and MeRIP-seq. The screened risk-associated SNP rs1059288 (A>G), which is located in the 3' UTR of TAPBP, was further validated in a case-control study involving 921 cases and 1077 controls. The results revealed a significant association between rs1059288 and the risk of CC (OR 1.48, 95% CI 1.13-1.92). Mechanistically, the presence of the risk G allele of rs1059288 was associated with increased m6A modification of TAPBP compared with the A allele. This modification was facilitated by the m6A methyltransferase METTL14 and the reading protein YTHDF2. Immunohistochemical staining of tissue microarrays containing 61 CC and 45 normal tissues showed an overexpression of TAPBP in CC. Furthermore, the upregulation of TAPBP promoted the growth and migration of CC cells as well as tumor-forming ability, inhibited apoptosis, and conferred increased resistance to commonly used chemotherapeutic drugs such as bleomycin, cisplatin, and doxorubicin. Knockdown of TAPBP inhibited the JAK/STAT/MICB signaling pathway in CC cells and upregulated certain immune genes including ISG15, IRF3, PTPN6, and HLA-A. These findings offer insights into the involvement of genetic variations in TAPBP in the development and progression of CC.

The Antigen-Processing Pathway via Major Histocompatibility Complex I as a New Perspective in the Diagnosis and Treatment of Endometriosis

Endometriosis is a debilitating gynecological disease defined as the presence of endometrium-like epithelium and/or stroma outside the uterine cavity. The most commonly affected sites are the pelvic peritoneum, ovaries, uterosacral ligaments, and the rectovaginal septum. The aberrant tissue responds to hormonal stimulation, undergoing cyclical growth and shedding similar to appropriately located endometrial tissue in the uterus. Common symptoms of endometriosis are painful periods and ovulation, severe pelvic cramping, heavy bleeding, pain during sex, urination and bowel pain, bleeding, and pain between periods. Numerous theories have been proposed to explain the pathogenesis of endometriosis. Sampson's theory of retrograde menstruation is considered to be the most accepted. This theory assumes that endometriosis occurs due to the retrograde flow of endometrial cells through the fallopian tubes during menstruation. However, it has been shown that this process takes place in 90% of women, while endometriosis is diagnosed in only 10% of them. This means that there must be a mechanism that blocks the immune system from removing endometrial cells and interferes with its function, leading to implantation of the ectopic endometrium and the formation of lesions. In this review, we consider the contribution of components of the Major Histocompatibility Complex (MHC)-I-mediated antigen-processing pathway, such as the ERAP, TAP, LMP, LNPEP, and tapasin, to the susceptibility, onset, and severity of endometriosis. These elements can induce significant changes in MHC-I-bound peptidomes that may influence the response of immune cells to ectopic endometrial cells.

Genetic variation that determines TAPBP expression levels associates with the course of malaria in an HLA allotype-dependent manner

HLA class I (HLA-I) allotypes vary widely in their dependence on tapasin (TAPBP), an integral component of the peptide-loading complex, to present peptides on the cell surface. We identified two single-nucleotide polymorphisms that regulate TAPBP messenger RNA (mRNA) expression in Africans, rs111686073 (G/C) and rs59097151 (A/G), located in an AP-2α transcription factor binding site and a microRNA (miR)-4486 binding site, respectively. rs111686073G and rs59097151A induced significantly higher TAPBP mRNA expression relative to the alternative alleles due to higher affinity for AP-2α and abrogation of miR-4486 binding, respectively. These variants associated with lower Plasmodium falciparum parasite prevalence and lower incidence of clinical malaria specifically among individuals carrying tapasin-dependent HLA-I allotypes, presumably by augmenting peptide loading, whereas tapasin-independent allotypes associated with relative protection, regardless of imputed TAPBP mRNA expression levels. Thus, an attenuated course of malaria may occur through enhanced breadth and/or magnitude of antigen presentation, an important consideration when evaluating vaccine efficacy.

The Impact of STAT3 rs1053005 Variation on Type 1 Diabetes Mellitus Susceptibility: Association Study and in Silico Analysis

AIMS

Type 1 diabetes (T1DM) is an autoimmune disorder with multiple genetic and environmental risk factors that are still poorly understood. The signal transducer and activator of transcription (STAT) proteins play a pivotal role in immune-cell genesis and regulation. This study aimed to determine the effect of rs1053005 single nucleotide polymorphism (SNP) in 3'-UTR of STAT3 mRNA on the susceptibility to T1DM in an Iranian population.

METHODS

PCR-RFLP was conducted on 250 T1DM patients and 250 control cases to assess STAT3 rs1053005 polymorphism. Moreover, several bioinformatics tools were employed to identify the candidate miRNAs targeting the STAT3 mRNA region under study as well as the effect of rs1053005 on their binding site.

RESULTS

Significant variations in the distribution of genotypes and alleles were seen between cases and controls. The comparison results of the frequency of AA, AG, and GG genotypes between T1DM patients and control groups were 49.2% versus 64.8%, 39.2 versus 30%, and 11.6 versus 5.2%, respectively. Individuals who carried GG genotype were at 2.93-fold increased risk of developing T1DM and the G allele was associated with 1.79-fold higher T1DM risk. Bioinformatics analysis demonstrated that due to rs1053005, the interaction of 3 miRNAs were broken, 3 were weakened, 2 were reinforced, and 4 binding sites were created.

CONCLUSION

The result of this study indicates an association between STAT3 rs1053005 and T1DM susceptibility which may be due to interference of the SNP with native-binding site of some predicted miRNAs.

APC gene 3'UTR SNPs and interactions with environmental factors are correlated with risk of colorectal cancer in Chinese Han population

Objective: To study the correlation between adenomatous polyposis coli (APC) gene 3′ untranslated region (UTR) single nucleotide polymorphisms (SNPs) and their interactions with environmental factors and the risk of colorectal cancer (CRC) in a Chinese Han population.

Methods: Genotypes of APC gene 3′UTR rs1804197, rs41116, rs448475, and rs397768 loci in 340 Chinese Han patients with CRC and 340 healthy controls were analyzed. All patients with CRC were analyzed for progression-free survival (PFS) during a 3-year follow-up.

Results: The risk of CRC in subjects carrying the APC gene rs1804197 A allele was 2.95-times higher than for the C allele carriers. The interactions of the rs1804197 SNP with body mass index (BMI) and smoking were associated with the risk of CRC. The risk of CRC in the APC gene rs397768 G allele carriers was 1.68-times higher than in the A allele carriers. The interaction between the rs397768 locus SNP and gender was also associated with the risk of CRC. The 3-year PFS of patients with APC gene rs1804197 AA genotype, CA genotype, and CC genotype CRC decreased in this order, with significant difference. In addition, the 3-year PFS of rs397768 locus GG genotype, AG genotype, and AA genotype CRC patients decreased in this order, and the difference was significant.

Conclusion: The rs1804197 locus in the 3′UTR region of the APC gene and its interactions with BMI and smoking are associated with the risk of CRC in a Chinese Han population. In addition, the interaction between rs397768 locus SNP and gender is related to the risk of CRC.

Genetic variants in the histone methylation and acetylation pathway and their risks in eight types of cancers

OBJECTIVES

The histone methylation and acetylation pathway genes regulate cell growth and survival. Aberrations in this pathway are implicated in a variety of cancers. This study aimed to identify germline genetic variants in histone methylation and acetylation pathway genes that may contribute to risk in eight types of cancers and to explore the relation between the whole pathway and their risks in these types of cancers.

METHODS

Germline genetic variants in 89 genes in the histone methylation and acetylation pathway were explored. Gene-based and pathway-based associations with eight types of cancers were analyzed using logistic regression models and the permutation-based adaptive rank-truncated product method, respectively.

RESULTS

Gene-level associations revealed that genetic variants in 45 genes were significantly associated with the risk of cancer. The total histone methylation and acetylation pathway was significantly associated with the risk of esophageal squamous cell carcinoma (P = 0.0492) and prostate (P = 0.0038), lung (P = 0.00015), and bladder cancer (P = 0.00135), but not with breast (P = 0.182), pancreatic (P = 0.336) and gastric cancer (P = 0.347) and renal cell carcinoma (P =0.828).

CONCLUSIONS

Our study suggested there is an association between germline genetic variation at the overall histone methylation and acetylation pathway level and some individual genes with cancer risk. Further studies are needed to validate these relations and to explore relative mechanisms.

Next-generation sequencing of colorectal cancers in chinese: identification of a recurrent frame-shift and gain-of-function Indel mutation in the TFDP1 gene

Abstract Re-sequencing of target genes is a highly effective approach for identifying mutations in cancers. Mutations, including indels (insertions, deletions, and the combination of the two), play important roles in carcinogenesis. Combining genomic DNA capture using high-density oligonucleotide microarrays (NimbleGen, Inc.) with next-generation high-throughput sequencing, we identified approximately 1600 indels for colorectal cancers in the Chinese population. Among them, 5 indels were localized to exonic regions of genes, including the TFDP1 (transcription factor Dp-1) gene. TFDP1 is an important transcription factor that coordinates with E2F proteins, thereby promoting transcription of E2F target genes and regulating the cell cycle and differentiation. We report here the identification of a recurrent frame-shift indel mutation (named indel84) in the TFDP1 gene in colorectal cancers by next-generation sequencing. We found in a validation set that TFDP1 indel84 is present in 70% of colorectal cancer (CRC) tissues. Wild-type TFDP1 encodes a protein of 410 amino acids with a potential DNA binding site at its N-terminal followed by several functional protein domains. The TFDP1 indel cDNA would generate an alternative TFDP1 protein missing the first 120 amino acids and potentially affecting the DNA binding domain. We further demonstrated that the TFDP1 indel84 mutation generated a gain-of-function phenotype by increasing cell proliferation, migration, and invasion of CRC cells. Our study identified a key molecular event for CRC that might have great diagnostic and therapeutic potentials.