MicroRNA-1307-3p contributes to breast cancer progression through PRM2.

BACKGROUND: Despite advances in screening and therapy, breast cancer (BC) remains the predominant cancer in women globally. Dysregulation of microRNAs (miRNAs) is pivotal in carcinogenesis across various cancers, including BC. Evidence indicates that miR-1307-3p is upregulated in BC tumors, yet its target genes are not fully elucidated. This study aimed to explore how miR-1307-3p regulates BC proliferation, migration, invasion, and angiogenesis and to identify potential target genes. METHODS: Basal miR-1307-3p levels were quantified in BC cell lines MDA-MB-231 and MCF-7, as well as MCF-10A using quantitative real-time reverse transcription-PCR (RT-qPCR). The impact of miR-1307-3p inhibition on BC cell proliferation, migration, invasion, and angiogenesis was assessed. Nine miRNA-target prediction databases identified potential miR-1307-3p targets. Target expression was validated using RT-qPCR, Western blot, and dual-luciferase reporter assays. MiR-1307-3p was overexpressed in MDA-MB-231 and MCF-7 compared to MCF-10A. RESULTS: Inhibiting miR-1307-3p significantly reduced BC cell proliferation, migration, invasion, and angiogenesis. Bioinformatics analysis identified 17 potential miR-1307-3p targets, with protamine 2 (PRM2) overexpression confirmed via Western blot and dual-luciferase assays. CONCLUSION: MiR-1307-3p overexpression in BC promotes proliferation, migration, invasion, and angiogenesis. PRM2 emerges as a novel miR-1307-3p target in BC.

Transcribed Ultraconserved Regions Are Associated with Clinicopathological Features in Breast Cancer.

Ultraconserved regions (UCRs) are 481 genome segments, with length longer than 200 bp, that are 100% conserved among humans, mice, and rats. The majority of UCRs are transcriptionally active (T-UCRs) as many of them produce non-coding RNAs. In a previous study, we evaluated the expression level of T-UCRs in breast cancer (BC) patients and found that 63% of transcripts correlated with some clinical and/or molecular parameter of BC. In this study, we delved into the expression levels of 12 T-UCRs and correlated them with clinicopathological parameters, immunohistochemical markers, and overall survival in two breast cancer cohorts: TCGA and Brazilian patients. We found that uc.268 is more expressed in TCGA patients under 40 years of age, associated with progesterone receptor (PR) and estrogen receptor (ER), and its high expression is found in luminal A. Lower uc.84 and uc.376 were respectively observed in metastatic and stage IV tumors associated with good prognostic in luminal B. Moreover, uc.84 was only related to the HER2+, while uc.376 was related to ER+ and PR+, and HER2+. A panel composed of uc.147, uc.271, and uc.427 distinguished luminal A from triple negative patients with an AUC of 0.9531 (sensitivity 92.19% and specificity 86.76%). These results highlight the potential role of T-UCRs in BC and provide insights into the potential application of T-UCRs as biomarkers.

A novel lncRNA derived from an ultraconserved region: lnc-uc.147, a potential biomarker in luminal A breast cancer.

The human genome contains 481 ultraconserved regions (UCRs), which are genomic stretches of over 200 base pairs conserved among human, rat, and mouse. The majority of these regions are transcriptionally active (T-UCRs), and several have been found to be differentially expressed in tumours. Some T-UCRs have been functionally characterized, but of those few have been associated to breast cancer (BC). Using TCGA data, we found 302 T-UCRs related to clinical features in BC: 43% were associated with molecular subtypes, 36% with oestrogen-receptor positivity, 17% with HER2 expression, 12% with stage, and 10% with overall survival. The expression levels of 12 T-UCRs were further analysed in a cohort of 82 Brazilian BC patients using RT-qPCR. We found that uc.147 is high expressed in luminal A and B patients. For luminal A, a subtype usually associated with better prognosis, high uc.147 expression was associated with a poor prognosis and suggested as an independent prognostic factor. The lncRNA from uc.147 (lnc-uc.147) is located in the nucleus. Northern blotting results show that uc.147 is a 2,8 kb monoexonic trancript, and its sequence was confirmed by RACE. The silencing of uc.147 increases apoptosis, arrests cell cycle, and reduces cell viability and colony formation in BC cell lines. Additionally, we identifed 19 proteins that interact with lnc-uc.147 through mass spectrometry and demonstrated a high correlation of lnc-uc.147 with the neighbour gene expression and miR-18 and miR-190b. This is the first study to analyse the expression of all T-UCRs in BC and to functionally assess the lnc-uc.147.

Targeting c-MYC in Platinum-Resistant Ovarian Cancer.

The purpose of this study was to investigate the molecular and therapeutic effects of siRNA-mediated c-MYC silencing in cisplatin-resistant ovarian cancer. Statistical analysis of patient's data extracted from The Cancer Genome Atlas (TCGA) portal showed that the disease-free (DFS) and the overall (OS) survival were decreased in ovarian cancer patients with high c-MYC mRNA levels. Furthermore, analysis of a panel of ovarian cancer cell lines showed that c-MYC protein levels were higher in cisplatin-resistant cells when compared with their cisplatin-sensitive counterparts. In vitro cell viability, growth, cell-cycle progression, and apoptosis, as well as in vivo therapeutic effectiveness in murine xenograft models, were also assessed following siRNA-mediated c-MYC silencing in cisplatin-resistant ovarian cancer cells. Significant inhibition of cell growth and viability, cell-cycle arrest, and activation of apoptosis were observed upon siRNA-mediated c-MYC depletion. In addition, single weekly doses of c-MYC-siRNA incorporated into 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG-2000)-based nanoliposomes resulted in significant reduction in tumor growth. These findings identify c-MYC as a potential therapeutic target for ovarian cancers expressing high levels of this oncoprotein.