MicroRNA (miRNA) plays a key role in development and specific biological processes, such as cell proliferation, differentiation, and apoptosis. Extensive studies of mammary miRNAs have been performed in different species and tissues. However, little is known about porcine mammary gland miRNAs. In this study, we report the identification and characterization of miRNAs in the lactating mammary gland in two distinct pig breeds, Jinhua and Yorkshire. Many miRNAs were detected as significantly differentially expressed between the two libraries. Among the differentially expressed miRNAs, many are known to be related to mammary gland development and lactation by interacting with putative target genes in previous studies. These findings suggest that miRNA expression patterns may contribute significantly to target mRNA regulation and influence mammary gland development and peak lactation performance. The data we obtained provide useful information about the roles of miRNAs in the biological processes of lactation and the mechanisms of target gene expression and regulation.

Breast cancer (BCa) remains as the second leading cause of cancer-related death in women worldwide. The majority of the deaths are due to its progression to metastatic BCa. Although Grb2-associated binding protein 1 (Gab1) has been implicated in tumor proliferation and metastasis in multiple tumors including colorectal cancer, hepatocellular carcinoma and ovarian cancer, whether and how it regulates BCa metastasis are still poorly understood. Western blot assay and immunohistochemical (IHC) staining were performed to assess expression of Gab1 in primary and metastatic BCa clinical samples. Biological function assay studies in vitro and in vivo were employed to investigate the functions of Gab1 during BCa metastasis. Co-immunoprecipitation (co-IP) assessment, western blot assay and immunofluorescence (IF) staining were carried out to investigate the underlying mechanism for the function of Gab1 on BCa metastasis. In this study, we found that expression level of Gab1 was increased significantly in BCa tissue samples compared to that in benign mammary hyperplastic tissues. Furthermore, elevated expression of Gab1 was positively associated with metastasis in HER2 and TNBC subtypes of BCa. In BCa cell line MDA-MB-231 and SK-BR3 cells, stable overexpression of Gab1 promoted, while knockdown of Gab1 inhibited cell migration in vitro and metastasis in vivo. Mechanistically, overexpression of Gab1 enhanced its interaction with Par3, a key component of the polarity-associated partitioning defective (PAR) complex, leading to a dissociation of the PAR complex. Consequently, dissociated PAR complex induced epithelial-to-mesenchymal transition (EMT) for breast tumor metastasis. By restoration assessment, we found that only re-expression of a fully functional Gab1, but not a mutant Gab1 that harbors either Par3 binding-deficiency or Par1b binding-deficiency, could reverse the repressive phenotype of cell migration in vitro and metastasis in vivo due to Gab1 knockdown. Our findings indicate that elevated expression of Gab1 promotes BCa metastasis by dissociating the PAR complex that leads to EMT, implicating a role of Gab1 as a potential biomarker of metastatic BCa. Moreover, inhibition of Gab1 expression might be a promising therapeutic strategy for BCa metastasis.

Hepatocellular Carcinoma (HCC) is a malignant tumor with high morbidity and mortality worldwide, which represents a serious threat to human life, health and quality of life. Blood-based detection is essential for HCC screening, early diagnosis, prognosis evaluation, and surveillance. Current non-invasive detection strategy including serum alpha-fetoprotein (AFP), ultrasound, computerized tomography, and magnetic resonance imaging. The limited specificity of an AFP and the dependence on operator experience and diagnostic personnel for ultrasound have constrained their utility in early HCC diagnosis. In recent years, with the development of various detection technologies, there has been an increasing focus on exploring blood-based detection markers for HCC. The types of markers include protein markers, DNA mutation, DNA epigenetic modification, mRNA, miRNA, and so on. However, numerous methodological and biological factors limit the clinical sensitivity and generalization performance of these new biomarkers. In this review, we describe the state-of-the-art technologies for cfDNA analysis, and discuss outstanding biological and technical challenges that, if addressed, would substantially improve HCC diagnostics and patient care.

Backgroud: Although recent studies have reported the regulation of the immune response in hepatocellular carcinoma (HCC) through DNA methylation, the comprehensive impact methylation modifications on tumor microenvironment characteristics and immunotherapy efficacy has not been fully elucidated.Methods: In this research, we conducted a comprehensive assessment of the patterns of DNA methylation regulators and the profiles of the tumor microenvironment (TME) in HCC, focusing on 21 specific DNA methylation regulators. We subsequently developed a unique scoring system, a DNA methylation score (DMscore), to assess the individual DNA methylation modifications among the three distinct methylation patterns for differentially expressed genes (DEGs).Results: Three distinct methylation modification patterns were identified with distinct TME infiltration characteristics. We demonstrated that the DMscore could predict patient subtype, TME infiltration, and patient prognosis. A low DMscore, characterized by an elevated tumor mutation burden (TMB), hepatitis B virus (HBV)/hepatitis C virus (HCV) infection, and immune activation, indicates an inflamed tumor microenvironment phenotype with a 5-year survival rate of 7.8%. Moreover, a low DMscore appeared to increase the efficacy of immunotherapy in the anti-CTLA-4/PD-1/PD-L1 cohort.Conclusions: In brief, this research has enhanced our understanding of the correlation between modifications in DNA methylation patterns and the profile of the tumor microenvironment in individuals diagnosed with HCC. The DMscore may serve as an alternative biomarker for survival and efficacy of immunotherapy in patients with HCC.