miR-221-3p Promotes Pancreatic Cancer Progression via Targeting P53 and PTEN

Background: To assess the regulatory role of microRNA-221-3p (miR-221-3p) as a modulator of pancreatic cancer (PC) cell apoptosis, invasion, migration, and proliferation through its ability to regulate P53 and PTEN expression.Methods: PCPATU8988 cells were used as a model in which high-level or low-level models of miR-221-3p expression were established, with qPCR being used to confirm transfection efficiency. CCK-8 assays were employed to evaluate the proliferation of these cells, with migration and invasion being assessed through appropriate in vitro assays. Western blotting was used to assess PTEN and P53 protein levels in these experimental cells. Flow cytometry was additionally used to assess the impact of experimental manipulations on cellular apoptosis.Results: MiR-221-3p overexpression enhanced the migratory, proliferative, and invasive activity of PCPATU8988 cells (P<0.01) and suppressed their apoptotic death (P<0.05), while miR-221-3p inhibition had the opposite impact. No differences in P53 and PTEN protein levels were detected when comparing the NC miR-221-3p mimic or inhibitor groups (P>0.05), whereas miR-221-3p mimic transfection significantly reduced the levels of these proteins (P<0.05).Conclusion: This analysis showed that miR-221-3p can drive PC cell proliferative, migratory, and invasive activity while suppressing the apoptotic death of these cells. Functionally, this miRNA can suppress P53 and PTEN protein expression. Overall, this suggests that miR-221-3p can regulate PC development by controlling the expression of these key oncogenic proteins.

LncRNA RP11-295G20.2 regulates hepatocellular carcinoma cell growth and autophagy by targeting PTEN to lysosomal degradation

PTEN is a crucial tumor suppressor and loss of PTEN protein is involved in various cancers. However, the detailed molecular mechanisms of PTEN loss in cancers remain elusive, especially the involvement of lncRNAs. Here, lncRNA RP11-295G20.2 is found to be significantly upregulated in hepatocellular carcinoma (HCC) and promotes the growth of liver cancer cells both in vitro and in vivo. Furthermore, RP11-295G20.2 inhibits autophagy in liver cancer cells. Interestingly, RP11-295G20.2 directly binds to the PTEN protein and leads to its degradation. RP11-295G20.2 expression is inversely correlated with PTEN protein expression in 82 TCGA/TCPA-LIHC samples. Surprisingly, RP11-295G20.2-induced PTEN degradation occurs through the lysosomal pathway instead of the proteasome pathway. RP11-295G20.2 binds to the N terminus of PTEN and facilitates the interaction of p62 with PTEN. Thus, PTEN is translocated into lysosomes and degraded. RP11-295G20.2 also influences AKT phosphorylation and forkhead box O 3a (FOXO3a) translocation into the nucleus, in turn regulating the transcription of autophagy-related genes. Collectively, RP11-295G20.2 directly binds to PTEN and enables its lysosomal degradation. This newly identified RP11-295G20.2/PTEN axis reveals an unexplored molecular mechanism regarding PTEN loss in liver cancer and might provide new therapeutic benefits for liver cancer patients.

USP52 inhibits cell proliferation by stabilizing PTEN protein in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer. Ubiquitination is closely related to the development of lung cancer. However, the biological importance of newly discovered ubiquitin specific peptidase 52 (USP52) in NSCLC remained unclear. Here, our findings identify USP52 as a novel tumor suppressor of NSCLC, the low expression of USP52 predicts a poor prognosis for NSCLC patients. This study demonstrates that USP52 inhibits cancer cell proliferation through downregulation of cyclin D1 as well as AKT/mTOR signaling pathway inhibition. Meanwhile, USP25 also suppresses NSCLC progression via enhancing PTEN stability in cancer cells, which further indicates the significance/importance of USP52 in NSCLC suppression.

Distinct, opposing functions for CFIm59 and CFIm68 in mRNA alternative polyadenylation of Pten and in the PI3K/Akt signalling cascade

ABSTRACTThe precise maintenance of PTEN dosage is crucial for tumor suppression across a wide variety of cancers. Post-transcriptional regulation of Pten heavily relies on regulatory elements encoded by its 3’UTR. We previously reported the important diversity of 3’UTR isoforms of Pten mRNAs produced through alternative polyadenylation (APA). Here, we reveal the direct regulation of Pten APA by the mammalian cleavage factor I (CFIm) complex, which in turn contributes to PTEN protein dosage. CFIm consists of the UGUA-binding CFIm25 and APA regulatory subunits CFIm59 or CFIm68. Deep sequencing analyses of perturbed (KO and KD) cell lines uncovered the differential regulation of Pten APA by CFIm59 and CFIm68 and further revealed that their divergent functions have widespread impact for APA in transcriptomes. Differentially regulated genes include numerous factors within the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signalling pathway that PTEN counter-regulates. We further reveal a stratification of APA dysregulation among a subset of PTEN-driven cancers, with recurrent alterations among PI3K/Akt pathway genes regulated by CFIm. Our results refine the transcriptome selectivity of the CFIm complex in APA regulation, and the breadth of its impact in PTEN-driven cancers.

PTEN and DNA Ploidy Status by Machine Learning in Prostate Cancer

Machine learning (ML) is expected to improve biomarker assessment. Using convolution neural networks, we developed a fully-automated method for assessing PTEN protein status in immunohistochemically-stained slides using a radical prostatectomy (RP) cohort (n = 253). It was validated according to a predefined protocol in an independent RP cohort (n = 259), alone and by measuring its prognostic value in combination with DNA ploidy status determined by ML-based image cytometry. In the primary analysis, automatically assessed dichotomized PTEN status was associated with time to biochemical recurrence (TTBCR) (hazard ratio (HR) = 3.32, 95% CI 2.05 to 5.38). Patients with both non-diploid tumors and PTEN-low had an HR of 4.63 (95% CI 2.50 to 8.57), while patients with one of these characteristics had an HR of 1.94 (95% CI 1.15 to 3.30), compared to patients with diploid tumors and PTEN-high, in univariable analysis of TTBCR in the validation cohort. Automatic PTEN scoring was strongly predictive of the PTEN status assessed by human experts (area under the curve 0.987 (95% CI 0.968 to 0.994)). This suggests that PTEN status can be accurately assessed using ML, and that the combined marker of automatically assessed PTEN and DNA ploidy status may provide an objective supplement to the existing risk stratification factors in prostate cancer.

Possible Role of PTEN expression in discriminating Benign Endometrial hyperplasia from Atypical Hyperplasia/Endometrial Intraepithelial Neoplasia in a series of Egyptian Patients

Background: Endometrial hyperplasia represents a heterogeneous group of lesions in response to the unopposed growth-promoting action of estrogen. WHO classified endometrial hyperplastic lesions into Benign Hyperplasia (BH) and atypical hyperplasia/ endometrial intraepithelial neoplasia AH/EIN. Phosphatase and tensin homolog (PTEN) is one of the earliest and most common genetic abnormalities detected in endometrioid adenocarcinoma (type I) and even in its precursors. This study aimed at histological evaluation of hyperplastic endometrial lesions according to WHO 2014 and investigating the role of PTEN expression in highlighting the precancerous group (AH/EIN). Patient and Method: This study included a series of 70 Egyptian patients suffered from hyperplastic endometrial lesions. They were previously diagnosed according to WHO1994 schema simple endometrial hyperplasia without atypia (n=18), simple endometrial hyperplasia with atypia (n=2), complex hyperplasia without atypia (n=25), complex hyperplasia with atypia (n=5) and hyperplastic endometrial polyps (n=20). Results: Cases were histologically re-evaluated according to WHO 2014 classification; BH (62 cases) and eight cases of AH/EIN. A significant difference in PTEN expression (regarding percentage and intensity of staining) in relation to histopathological diagnosis was detected (P-value 0.02 and <0.05, respectively). The sensitivity and specificity of the absence of diffuse PTEN protein expression (>50%) to detect AH/EIN were 100% and 77.4%, respectively. Conclusion: Diffuse, dim or loss of immunohistochemical expression of PTEN protein is significantly correlated with the new WHO classification segregation of AH/EIN as precancerous lesions. However, further studies are recommended to confirm this association.

PTEN protein expression has role in predicting disease-free-interval in endometrioid endometrial carcinoma

Objectives To determine the significance of tumour PTEN protein expression in endometrioid endometrial carcinoma (EEC) and it is correlation with tumour characteristics. Methods A total of 30 eligible archived paraffin-embedded tissue blocks from 61 EEC cases (January 2015–December 2017) were retrieved from the Histopathology Laboratory in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) following institutional ethic approval. For PTEN protein detection, immunohistochemistry (IHC) staining was performed and the data was correlated with clinicopathologic parameters. Results Fourteen samples (46.7%) showed positive PTEN protein expression, while 16 (53.3%) were negative. The mean age was 62.00 ± 9.51 years old, while the mean Body Mass Index (BMI) was 27.28 ± 7.16 kg/m2. There was no significant difference between age (p=0.27, 95% CI: −10.98 to 3.21) and BMI (p=0.67, 95% CI: −4.30 to 6.58) with PTEN protein expression. There were significant correlation between PTEN protein expression with myometrial invasion (p=0.010), but not with lymphovascular space invasion (p=0.743), grade (p=0.532), stage (p=0.733) and CA-125 level (p=0.47). The higher stage correlates with the presence of LVSI (p=0.002). PTEN positive associated with longer disease-free-interval (p=0.025), but not improving the overall survival (p=0.38) Conclusions Positive PTEN protein expression correlates with less myometrial invasion.