Molecular Epidemiology of Epstein-Barr Virus in Women Breast Cancer in Congo Brazzaville

Introduction: the Epstein Barr virus is one of the very first oncogenic viruses to be identified as responsible for human malignancies. Its role as an etiological agent of breast cancer remains controversial, however, despite the growing molecular evidence. The aim of this study was detected the presence of EBV DNA in patients with breast cancer in the Republic of Congo. Methods: The study was conducted on 90 samples of formalin fixed and paraffin-embedded tissue blocks (FFPE) from breast cancer tissue. The immunohistochemistry technique was used to test for the expression of the LMP1 antibody and DNA was extracted from all blocks of formalin-fixed and paraffin-embedded breast cancer tissue (FFPE) to detect presence of EBV 1 DNA by real-time polymerase chain reaction (PCR). Results: EBV was detected in 12.33% (12/90) of formalin-fixed, paraffin-embedded (FFPE) breast cancer tissue blocks. All formalin-fixed, paraffin-embedded (FFPE) breast cancer tissue blocks with positive EBV DNA were high tumor grades (II and III). Overall EBV infection with clinicopathological features of breast cancer cases showed no significant difference (P>0.05). However, a statistically significant difference was observed between EBV infection and histological types (P=0.04). Conclusion: Our results provide evidence for the presence of EBV DNA in female breast cancer in Congo Brazzaville. However, this evidence is substantial but inconclusive for the involvement of viruses in the development of breast cancer. Therefore, future investigations will be needed to elucidate the exact role of EBV in breast cancer in women in the Republic of Congo. Key words: EBV, breast cancer, women, Congo Brazzaville.

Eliminating fibroblast activation protein-α expressing cells by photoimmunotheranostics

Photoimmunotherapy (PIT) using an antibody conjugated to a near infrared dye IR700 is achieving significant success in target-specific elimination of cells. Fibroblast activation protein alpha (FAP-α) is an important target in cancer because of its expression by cancer associated fibroblasts (CAFs) as well as by some cancer cells. CAFs that express FAP-α have protumorigenic and immune suppressive functions. Using immunohistochemistry of human breast cancer tissue microarrays, we identified an increase of FAP-α+ CAFs in invasive breast cancer tissue compared to adjacent normal tissue. We found FAP-α expression increased in fibroblasts co-cultured with cancer cells. In proof-of-principle studies, we engineered human FAP-α overexpressing MDA-MB-231 and HT-1080 cancer cells and murine FAP-α overexpressing NIH-3T3 fibroblasts to evaluate several anti-FAP-α antibodies and selected AF3715 based on its high binding-affinity with both human and mouse FAP-α. After conjugation of AF3715 with the phthalocyanine dye IR700, the resultant antibody conjugate, FAP-α-IR700, was evaluated in cells and tumors for its specificity and effectiveness in eliminating FAP-α expressing cell populations with PIT. FAP-α-IR700-PIT resulted in effective FAP-α-specific cell killing in the engineered cancer cells and in two patient-derived CAFs in a dose-dependent manner. Following an intravenous injection, FAP-α-IR700 retention was three-fold higher than IgG-IR700 in FAP-α overexpressing tumors, and two-fold higher compared to wild-type tumors. FAP-α-IR700-PIT resulted in significant growth inhibition of tumors derived from FAP-α overexpressing human cancer cells. A reduction of endogenous FAP-α+ murine CAFs was identified at 7 days after FAP-α-IR700-PIT. FAP-α-targeted NIR-PIT presents a promising strategy to eliminate FAP-α+ CAFs.

MiR-92b-3p Inhibits Proliferation of HER2-Positive Breast Cancer Cell by Targeting circCDYL

ObjectivesCircular RNA (circRNA) is a novel class of RNA, which exhibits powerful biological function in regulating cellular fate of various tumors. Previously, we had demonstrated that over-expression of circRNA circCDYL promoted progression of HER2-negative (HER2–) breast cancer via miR-1275-ULK1/ATG7-autophagic axis. However, the role of circCDYL in HER2-positive (HER2+) breast cancer, in particular its role in modulating cell proliferation, one of the most important characteristics of cellular fate, is unclear.Materials and methodsqRT-PCR and in situ hybridization analyses were performed to examine the expression of circCDYL and miR-92b-3p in breast cancer tissues or cell lines. The biological function of circCDYL and miR-92b-3p were assessed by plate colony formation and cell viability assays and orthotopic animal models. In mechanistic study, circRNAs pull-down, RNA immunoprecipitation, dual luciferase report, western blot, immunohistochemical and immunofluorescence staining assays were performed.ResultsCircCDYL was high-expressed in HER2+ breast cancer tissue, similar with that in HER2– breast cancer tissue. Silencing HER2 gene had no effect on expression of circCDYL in HER2+ breast cancer cells. Over-expression of circCDYL promoted proliferation of HER2+ breast cancer cells but not through miR-1275-ULK1/ATG7-autophagic axis. CircRNA pull down and miRNA deep-sequencing demonstrated the binding of miR-92b-3p and circCDYL. Interestingly, circCDYL did not act as miR-92b-3p sponge, but was degraded in miR-92b-3p-dependent silencing manner. Clinically, expression of circCDYL and miR-92b-3p was associated with clinical outcome of HER2+ breast cancer patients.ConclusionMiR-92b-3p-dependent cleavage of circCDYL was an essential mechanism in regulating cell proliferation of HER2+ breast cancer cells. CircCDYL was proved to be a potential therapeutic target for HER2+ breast cancer, and both circCDYL and miR-92b-3p might be potential biomarkers in predicting clinical outcome of HER2+ breast cancer patients.

LncRNA EGFR-AS1 Regulates Breast Cancer Cells Function and Sensitivity to Docetaxel Via the miR-149-5p/ELP5 Axis

Background: Recently, an increasing number of studies have focused on investigating long non-coding RNAs (lncRNAs) and their role in regulating the progression of various cancer types. However, the biological effects and underlying mechanisms of EGFR-AS1, a typical lncRNA, remain largely unclear in breast cancer.Methods: Differential expression of EGFR-AS1 in breast cancer tissue was analyzed using an integrative database and verified in breast cancer tissue samples and cells via real-time PCR analysis and western blotting analysis. The tumor promoter role of EGFR-AS1 in breast cancer cells was determined through MTT, EDU analysis, colony formation and transwell assays,and the effect of EGFR-AS1 on docetaxel drug sensitivity was examined. We then performed bioinformatic analysis and the dual-luciferase reporter assay to identify the binding sites of EGFR-AS1/miR-149-5p and miR-149-5p/ELP5. Results from western blotting and biological function studies provided insights into whether the EGFR-AS1/miR-149-5p/ELP5 axis regulates breast cancer development in vitro and in vivo. Results: EGFR-AS1 is upregulated in breast cancer tissues and cells and promotes the progression of breast cancer cells both in vitro and in vivo. Moreover, miR-149-5p is downregulated in breast cancer tissues and cell lines. Mechanistically, EGFR-AS1 regulates ELP5 levels by sponging miR-149-5p, thereby affecting cell progression and promoting epithelial-to-mesenchymal transition. Hence, the EGFR-AS1/miR-149-5p/ELP5 axis is involved in breast cancer proliferation, migration, invasion, and resistance to the chemotherapeutic drug, docetaxel, in breast cancer cells. Conclusions: EGFR-AS1 sponges miR-149-5p to affect the expression level of ELP5 ultimately acting as a new tumor promotor in breast cancer. This study provides novel insights into diagnostic and docetaxel-related chemotherapy targets for breast cancer.