Negative regulation of CD44st by miR-138-5p affects the invasive ability of breast cancer cells and patient prognosis after breast cancer surgery

Identification and Validation of circDOCK1/miR-138-5p/GRB7 Axis for Promoting Breast Cancer Progression

Background

Non-coding RNAs have received increasing attention in human tumors, with RNA interaction networks playing important roles in breast cancer. This study aims to explore novel circular RNAs and their mechanisms of biological function in breast cancer.

Methods

Six HER2-positive breast cancer tissues and paired normal tissues were obtained for the whole transcriptome RNA sequencing. Differentially expressed (DE) circRNAs, miRNAs and mRNAs were identified and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DERNAs were performed. DECircRNAs- DEmiRNAs- DEmRNAs networks were constructed and further verified by bioinformatics database analyses, luciferase assays and RIP assays. The expression level of circDOCK1 in breast cancer specimens was measured using qRT-PCR. Functional rescue experiments were conducted to explore the role of circDOCK1/miR-138-5p/GRB7 axis in breast cancer cells. The correlation of circDOCK1 expression and clinicopathologic features of 102 HER2 positive breast cancer patients was analyzed.

Results

A total of 6960 DEmRNAs, 133 DE miRNAs and 1691 DE circRNAs were identified from HER2-positive breast cancer tissues and paracancerous tissues. Enrichment Analysis showed that the differential mRNAs were associated with cell division in biological processes and cell cycle and signaling pathways. GO and KEGG analysis demonstrated that DE circRNAs were mainly enriched in double-strand break repair, positive regulation of transcription by RNA polymerase II, nucleoplasma, nucleus, chromatin binding and protein binding. Forty networks of competing endogenous RNAs (ceRNAs) were constructed and circDOCK1/miR-138-5p/GRB7 axis was verified. Functional experiments revealed that the axis promotes migration and invasion of breast cancer cells. CircDOCK1 expression was elevated in breast cancer patients and correlated with adverse clinicopathologic parameters. Patients with high circDOCK1 level had poor outcomes.

Conclusion

A novel circDOCK1/miR-138-5p/GRB7 axis promotes HER2 positive breast cancer metastasis and progression, providing a potential therapeutic target in the treatment of breast cancer.

Hyaluronic acid/dextran-based polymeric micelles co-delivering ursolic acid and doxorubicin to mitochondria for potentiating chemotherapy in MDR cancer

Cancer multidrug resistance (MDR) dramatically hindered the efficiency of standard chemotherapy. Mitochondria are highly involved in the occurrence and development of MDR; thus, inducing its malfunction will be an appealing strategy to treat MDR tumors. In this paper, a natural polysaccharides-based nanoplatform (TDTD@UA/HA micelles) with cell and mitochondria dual-targeting ability was facilely fabricated to co-deliver ursolic acid (UA) and doxorubicin (DOX) for combinatorial MDR therapy. TDTD@UA/HA micelles featured a spherical morphology, narrow size distribution (∼140 nm), as well as favorable drug co-loading capacity (DOX: 8.41 %, UA: 9.06 %). After hyaluronic acid (HA)-mediated endocytosis, the lysosomal hyaluronidase promoted the degradation of HA layer and then the positive triphenylphosphine groups were exposed, which significantly enhanced the mitochondria-accumulation of nano micelles. Subsequently, DOX and UA were specifically released into mitochondria under the trigger of endogenous reactive oxygen species (ROS), followed by severe mitochondrial destruction through generating ROS, exhausting mitochondrial membrane potential, and blocking energy supply, etc.; ultimately contributing to the susceptibility restoration of MCF-7/ADR cells to chemotherapeutic agents. Importantly, TDTD@UA/HA micelles performed potent anticancer efficacy without distinct toxicity on the MDR tumor-bearing nude mice model. Overall, the versatile nanomedicine represented a new therapeutic paradigm and held great promise in overcoming MDR-related cancer.

Evaluation of MMP-13 and Micro RNA-138 as prognostic biomarkers for breast cancer in Egyptian women patients

BACKGROUND

Elevated serum levels of MMP-13 are linked to tumor growth and metastasis, while miR-138 dysregulation is observed in breast cancer cases. The aim of this study is to investigate the expression of miR-138 and MMP-13 levels as potential biomarkers for the prognosis of breast cancer.

PATIENTS AND METHOD

In this retrospective case-control study, 119 female subjects were recruited and divided into three groups. MMP-13 level was measured using Enzyme Linked Immunosorbent Assay (ELISA), while real-time PCR technique was employed to quantify miR-138 expression.

RESULTS

Both non-metastatic and metastatic groups showed significantly higher levels of serum MMP-13 compared to other groups. MMP-13 levels are significantly increased among patients with advanced tumor size, lymph node metastasis, and triple-negative breast cancer cases. An inverse significant association between MMP-13 levels and response to treatment was observed. Expression of miR-138 underwent a significant down-regulation in breast cancer patients, and a statistically significant association was established between miR-138 expression and triple-negative breast cancer cases. A positive association was detected between the increase in miR-138 expression and the good response to treatment. The expression of miR-138 was inversely correlated with the MMP-13 levels.

CONCLUSION

MMP-13 levels were significantly higher in breast cancer, especially in advanced cases, suggesting its role in promoting tumor invasion and metastasis. MiR-138 was down-regulated in breast cancer, especially in triple-negative breast cancer patients, rendering it a promising biomarker for triple-negative breast cancer. Modulation of miR-138 expression and MMP-13 levels may represent therapeutic targets for breast cancer.