PIWI-Like 1 and PIWI-Like 2 Expression in Breast Cancer

A comprehensive review on the role of PIWI-interacting RNA (piRNA) in gynecological cancers

Gynecological cancers are currently a major public health concern due to increase in incidence and mortality globally. PIWI-interacting RNA (piRNA) are small non-coding RNA consisting of 24-32 nucleotides that plays regulatory role by interacting with piwi family of protein. Recent studies have revealed that piRNAs are expressed in various kinds of human tissues and influences key signalling pathways at transcriptional and post transcriptional levels. Studies have also that suggested piRNA and PIWI proteins display frequently altered expression in several cancers. Recent research has indicated that abnormal expression of piRNA may play a significant role in development and progression of gynecological cancers. Clinical studies suggested that, abnormally expressed piRNAs may serve as diagnostic and prognostic marker, and as potential therapeutic targets in these cancers. In the present review article, we discussed the emerging role of piRNA and their utility as diagnostic and prognostic marker in gynecological cancers.

Elevated expression patterns of P-element Induced Wimpy Testis (PIWI) transcripts are potential candidate markers for Hepatocellular Carcinoma

BACKGROUND

P-Element-induced wimpy testis (PIWI) proteins, when in combination with PIWI-interacting RNA (piRNA), are engaged in the epigenetic regulation of gene expression in germline cells. Different types of tumour cells have been found to exhibit abnormal expression of piRNA, PIWIL-mRNAs, and proteins. We aimed to determine the mRNA expression profiles of PIWIL1, PIWIL2, PIWIL3, & PIWIL4, in hepatocellular carcinoma patients, and to associate their expression patterns with clinicopathological features.

METHODS

The expression patterns of PIWIL1, PIWIL2, PIWIL3, PIWIL4 mRNA, was assessed via real-time quantitative polymerase chain reaction (RT-QPCR), on tissue and serum samples from HCC patients, their impact for diagnosis was evaluated by ROC curves, prognostic utility was determined, and In Silico analysis was conducted for predicted variant detection, association with HCC microRNAs and Network Analysis.

RESULTS

Expression levels were significantly higher in both HCC tissue and serum samples than in their respective controls (p< 0.001). Additionally, the diagnostic performance was assessed, Risk determination was found to be statistically significant.

CONCLUSION

PIWIL mRNAs are overexpressed in HCC tissue and serum samples, the expression patterns could be valuable molecular markers for HCC, due to their association with age, tumour grade and pattern. To the best of our knowledge, our study is the first to report the expression levels of all PIWIL mRNA and to suggest their remarkable values as diagnostic and prognostic biomarkers, in addition to their correlation to HCC development. Additionally, a therapeutic opportunity might be also suggested through in silico miRNA prediction for HCC and PIWIL genes through DDX4 and miR-124-3p.

Expression of the Immunohistochemical Markers CK5, CD117, and EGFR in Molecular Subtypes of Breast Cancer Correlated with Prognosis

Molecular-based subclassifications of breast cancer are important for identifying treatment options and stratifying the prognosis in breast cancer. This study aimed to assess the prognosis relative to disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer (TNBC) and other subtypes, using a biomarker panel including cytokeratin 5 (CK5), cluster of differentiation 117 (CD117), and epidermal growth factor receptor (EGFR). This cohort-case study included histologically confirmed breast carcinomas as cohort arm. From a total of 894 patients, 572 patients with early breast cancer, sufficient clinical data, and archived tumor tissue were included. Using the immunohistochemical markers CK5, CD117, and EGFR, two subgroups were formed: one with all three biomarkers negative (TBN) and one with at least one of those three biomarkers positive (non-TBN). There were significant differences between the two biomarker subgroups (TBN versus non-TBN) in TNBC for DFS (p = 0.04) and OS (p = 0.02), with higher survival rates (DFS and OS) in the non-TBN subgroup. In this study, we found the non-TBN subgroup of TNBC lesions with at least one positive biomarker of CK5, CD117, and/or EGFR, to be associated with longer DFS and OS.

Piwi-interacting RNA-651 promotes cell proliferation and migration and inhibits apoptosis in breast cancer by facilitating DNMT1-mediated PTEN promoter methylation

Piwi-interacting RNAs (piRNAs/piRs) are small non-coding RNAs that play important roles in stablizing genome through silencing transposable genetic elements. The piR-651 was reported to be dysregulated in several human solid cancer tissues, such as gastric and lung cancers. However, the role of piRNA-651 in carcinogenesis of breast cancer has not been defined. We found that piR-651 was highly expressed in breast cancer tissues and cell lines. Overexpression of piR-651 facilitated cell proliferation and invasion, restrained cell apoptosis and the percentage of arrested cells in G0/G1 phase, accompanied by upregulated expression of oncogenes (MDM2, CDK4 and Cyclin D1), whereas piR-651 downregulation showed the opposite effects. Additionally, piR-651 could promote phosphatase and tensin homolog (PTEN) methylation and its downregulated expression by recruiting DNA methyltransferase 1 (DNMT1) to the PTEN promoter region through complex formation with PIWIL2. PTEN overexpression reversed the effects of upregulated piR-651 on cell functions. This study reveals that piR-651 promotes proliferation and migration and induces apoptosis of breast cancer cells by facilitating DNMT1-mediated PTEN promoter methylation, which may provide a potential therapeutic mechanism for breast cancer.