Breast cancer (BC) displays striking genetic, epigenetic and phenotypic diversity. N6-methyladenosine (m6A) in mRNA has emerged as a crucial epitranscriptomic modification that controls cancer self-renewal and cell fate. However, the key enzymes of m6A expression and function in human breast carcinogenesis remain unclear. The expression of m6A methylases (METTL3, METTL14 and WTAP) and demethylases (FTO and ALKBH5) were analyzed by using ONCOMINE and The Cancer Genome Atlas databases and in 36 pairs of BC and adjacent non-cancerous tissue. The level of m6A in BC patients was detected by ELISA, and the function of m6A was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay and transwell assay. The database of bc-GenExMiner v4.0, Kaplan-Meier Plotter and cBioPortal were queried for correlation, mutation and prognosis analysis of BC. The m6A methylases and demethylases were dysregulated in several major malignant tumors. Specifically, the expression of all m6A methylases was reduced in BC as compared with normal controls, but the demethylase ALKBH5 was induced in ONCOMINE databases and confirmed in clinical patients. METTL14 expression was positively correlated with METTL3 expression, and both showed high expression in normal breast-like and luminal-A and -B BC. Functionally, reducing m6A expression by overexpressing METTL14 and/or knockdown of ALKBH5 could inhibit breast cell viability, colony formation and cell migration. Furthermore, Kaplan-Meier, meta-analysis and univariate Cox assay showed that the expression of m6A members including METTL3, METTL14, WTAP and FTO but not their gene mutation and amplification, was tightly associated with cancer progression and poor survival. Changes of m6A modulators reduced m6A may promote tumorigenesis and predict poor prognosis in BC.

Background: HPV has been found repeatedly in esophageal carcinoma tissues. However, reported detection rates of HPV DNA in these tumors have varied markedly. Differences in detection methods, sample types, and geographic regions of sample origin have been suggested as potential causes of this discrepancy.Methods: HPV L1 DNA and HPV genotypes were evaluated in 435 esophageal carcinoma specimens collected from four geographic regions with different ethnicities including Anyang in north China, Shantou in south China, Xinjiang in west China, and the United States. The HPV L1 fragment was detected using SPF1/GP6+ primers. HPV genotyping was performed using genotype specific PCR.Results: Two hundred and forty four of 435 samples (56.1%) tested positive for HPV L1. Significant differences in detection rate were observed neither among the three areas of China nor between China and the US. HPV6, 16, 18, 26, 45, 56, 57, and 58 were identified in L1 positive samples. HPV16 and 57 were the most common types in all regions, followed by HPV26 and HPV18.Conclusions: HPV infection is common in esophageal carcinoma independent of region and ethnic group of origin. Findings in this study raise the possibility that HPV is involved in esophageal carcinogenesis. Further investigation with a larger sample size over broader geographic areas may be warranted.

Epoxyeicosatrienoic acids (EETs) are derived from arachidonic acid by cytochrome P450 (CYP) and metabolized by soluble epoxide hydrolase (sEH). EETs have been associated with cardiovascular disease, diabetes and several cancer diseases. However, the distribution in tissue and role of CYP2C8, 2C9, 2J2 and sEH in human breast carcinogenesis remains uncertain. Breast cancer (BC) and adjacent noncancerous tissue was obtained from 40 breast cancer patients in the Chaoshan region in China from 2010 to 2012. The level of 14,15-EET/14,15-DHET in BC patients was detected by ELISA; the expression and distribution of CYP2C8, 2C9, 2J2 and sEH was determined by quantitative RT-PCR and immunohistochemical staining; and cell proliferation and migration was analyzed by MTT and transwell assays, respectively. The median 14,15-EET and 14,15-EET/DHET level was 2.5-fold higher in BC than noncancerous tissue. The mRNA and protein levels of CYP2C8, 2C9 and 2J2 were higher, and sEH was lower in BC than noncancerous tissue. Furthermore, CYP2C8 and 2C9 protein levels positively correlated with Ki67 status, and CYP2J2 levels positively correlated with histological grade and tumor size. The sEH protein level negatively correlated with tumor size, estrogen receptors and Ki67. In MDA-MB-231 cells, siRNA knockdown of CYP2C8, 2C9 or 2J2 reduced cell proliferation, by 24.5%, 29.13%, or 22.7% and decreased cell migration by 49.1%, 44.9%, and 50.9%, respectively. Similarly, with adenovirus overexpression of sEH, both cell proliferation and migration rates were reduced by 31.4% and 45.8%, respectively. The present study shows that elevated EET levels in BC tissues are associated with upregulation of CYP2C8, 2C9, and 2J2, and downregulation of sEH, and are also associated with aggressive cell behavior in BC patients.

Both N6-methyladenosine (m6A) RNA modification and microRNAs (miRNAs) are common regulatory mechanisms for gene post-transcription by modulating mRNA stability and translation. They also share the same 3′-untranslated regions (UTRs) regions for their target gene. However, little is known about their potential interaction in cell development and biology. Here, we aimed to investigate how m6A regulates the specific miRNA repression during cardiac development and hypertrophy. Our multiple lines of bioinformatic and molecular biological evidence have shown that m6A modification on cardiac miR-133a target sequence promotes miR-133a repressive effect via AGO2-IGF2BP2 (Argonaute 2—Insulin-like growth factor 2 mRNA binding protein 2) complex. Among 139 cardiac miRNAs, only the seed sequence of miR-133a was inversely complement to m6A consensus motif “GGACH” by sequence alignment analysis. Immunofluorescence staining, luciferase reporter, and m6A-RIP (RNA immunoprecipitation) assays revealed that m6A modification facilitated miR-133a binding to and repressing their targets. The inhibition of the miR-133a on cardiac proliferation and hypertrophy could be prevented by silencing of Fto (FTO alpha-ketoglutarate dependent dioxygenase) which induced m6A modification. IGF2BP2, an m6A binding protein, physically interacted with AGO2 and increased more miR-133a accumulation on its target site, which was modified by m6A. In conclusion, our study revealed a novel and precise regulatory mechanism that the m6A modification promoted the repression of specific miRNA during heart development and hypertrophy. Targeting m6A modification might provide a strategy to repair hypertrophic gene expression induced by miR-133a.

Background: Human papillomavirus (HPV) infection is a major risk factor for the development of nearly all cases of cervical cancer worldwide. The presence of HPV DNA in cases of esophageal squamous-cell carcinoma (ESCC) has been reported repeatedly from Shantou, China, and other regions with a high incidence of esophageal carcinoma (EC). However, unlike in cervical squamous-cell carcinoma (CSCC), in ESCC, the characteristics of HPV are unclear. Thus, the role of high-risk HPV types in the carcinogenesis of ESCC remains uncertain. Methods: Seventy cases of ESCC with 60 controls and 39 cases of CSCC with 54 controls collected from patients in Shantou region in China were compared for the distributions of HPV-16, -18 and -58; viral load; and viral integration using real-time PCR assay and HPV-16 expression using immunostaining. Results: The detection rates and viral loads of HR-HPV infection were significantly lower in ESCC than in CSCC (50.0% vs. 79.48%, P = 0.005; 2.55 ± 3.19 vs. 361.29 ± 441.75, P = 0.002, respectively). The combined integration level of HPV-16, -18 and -58 was slightly lower in ESCC than in CSCC (P = 0.022). HPV-16 expression was detected in 59.26% of ESCC tissue and significantly associated with tumour grade (P = 0.027). Conclusions: High levels of HR-HPV expression and integration may be an indicator of the risk of ESCC, at least for patients in the Shantou region of China. However, a relatively low HPV copy number and infection rate in ESCC is unlikely to play an essential a role in the carcinogenesis of ESCC as in cervical cancer. Factors other than HR-HPV infection may contribute to the carcinogenesis of ESCC.

KRAS and TP53 mutations are the two most common driver mutations in patients with lung adenocarcinoma (LUAD), and they appear to reduce latency and increase metastatic proclivity when a KRAS and TP53 co-mutation (KRAS/TP53-mut) occurs. However, the molecular mechanism involved is unclear. N⁶-methyladenosine (m⁶A), the most abundant RNA modification in mammal mRNAs, plays a critical role in tumorigenesis. Here, we used genomic and transcriptomic data and found that only LUAD patients with KRAS/TP53-mut, but not an individual mutation, appeared to exhibit poor overall survival when compared with patients without KRAS and TP53 mutation (wildtype). Subsequently, we analyzed the differential expression of the 15-m⁶A-related genes in LUAD with different mutations and found that YTHDF1 was the most upregulated in KRAS/TP53-mut patients and associated with their adverse prognosis. Bioinformatics and experimental evidence indicated that elevated YTHDF1 functionally promoted the translation of cyclin B1 mRNA in an m⁶A-dependent manner, thereby facilitating the tumor proliferation and poor prognosis of LUAD with KRAS/TP53-mut. Furthermore, the concurrent increase in YTHDF1 and cyclin B1 was confirmed by immunohistochemistry staining in patients with co-occurring KRAS/TP53 mutations. YTHDF1 was correlated with an unfavorable clinical stage and tumor size. Collectively, we identified and confirmed a novel “YTHDF1–m⁶A–cyclin B1 translation” axis as an essential molecular pathway for the prognosis of KRAS/TP53-mut LUAD.