Aurora Kinase A and Bcl-xL Inhibition Suppresses Metastasis in Triple-Negative Breast Cancer

A comprehensive review on role of Aurora kinase inhibitors (AKIs) in cancer therapeutics

Aurora kinases (AURKs) are a family of serine /threonine protein kinases that have a crucial role in cell cycle process mainly in the event of chromosomal segregation, centrosome maturation and cytokinesis. The family consists of three members including Aurora kinase A (AURK-A), Aurora kinase B (AURK-B) and Aurora kinase C (AURK-C). All AURKs contain a conserved kinase domain for their activity but differ in their cellular localization and functions. AURK-A and AURK-B are expressed mainly in somatic cells while the expression of AURK-C is limited to germ cells. AURK-A promotes G2 to M transition of cell cycle by controlling centrosome maturation and mitotic spindle assembly. AURK-B and AURK-C form the chromosome passenger complex (CPC) that ensures proper chromosomal alignments and segregation. Aberrant expression of AURK-A and AURK-B has been detected in several solid tumours and malignancies. Hence, they have become an attractive therapeutic target against cancer. The first part of this review focuses on AURKs structure, functions, subcellular localization, and their role in tumorigenesis. The review also highlights the functional and clinical impact of selective as well as pan kinase inhibitors. Currently, >60 compounds that target AURKs are in preclinical and clinical studies. The drawbacks of existing inhibitors like selectivity, drug resistance and toxicity have also been addressed. Since, majority of inhibitors are Aurora kinase inhibitor (AKI) type-1 that bind to the active (DFGin and Cin) conformation of the kinase, this information may be utilized to design highly selective kinase inhibitors that can be combined with other therapeutic agents for better clinical outcomes.

Gains of 20q11.21 in human pluripotent stem cells: Insights from cancer research

The genetic abnormalities observed in hPSC cultures worldwide have been suggested to pose an important hurdle in their safe use in regenerative medicine due to the possibility of oncogenic transformation by mutant cells in the patient posttransplantation. One of the best-characterized genetic lesions in hPSCs is the gain of 20q11.21, found in 20% of hPSC lines worldwide, and strikingly, also amplified in 20% of human cancers. In this review, we have curated the existing knowledge on the incidence of this mutation in hPSCs and cancer, explored the significance of chromosome 20q11.21 amplification in cancer progression, and reviewed the oncogenic role of the genes in the smallest common region of gain, to shed light on the significance of this mutation in hPSC-based cell therapy. Lastly, we discuss the state-of-the-art strategies devised to detect aneuploidies in hPSC cultures, avoid genetic changes in vitro cultures of hPSCs, and strategies to eliminate genetically abnormal cells from culture.

Inhibitory effect of miR342 on the progression of triple-negative breast cancer cells in vitro and in the mice model

Introduction

Breast cancer is the most common cancer in women worldwide, and the triple-negative subtype is the most invasive, with limited therapeutic options. Since miRNAs are involved in many cellular processes, they harbor great value for cancer treatment. Therefore, in this study, we have investigated the anti-proliferative and anti-invasive roles of miR342 in 4T1 triple-negative cells in vitro and also studied the effect of this miRNA on tumor progression and the expression of its target genes in vivo.

Methods

4T1 cells were transduced with conditioned media of miR342-transfected Hek-LentiX cells. MTT and clonogenic assays were used to assess the viability and colony-forming ability of 4T1 cells. Apoptosis and invasion rates were respectively evaluated by annexin/7-AAD and wound healing assays. At last, in vivo tumor progression was evaluated using H&E staining, real-time PCR, and immunohistochemistry.

Results

The viability of transduced-4T1 cells reduced significantly 48 hours after cell seeding and colony forming ability of these cells reduced to 50% of the control group. Also, miR342 imposed apoptotic and anti-invasive influence on these cells in vitro. A 30-day follow-up of the breast tumor in the mice model certified significant growth suppression along with reduced mitotic index and tumor grade in the treatment group. Moreover, decreased expression of Bcl2l1, Mcl1, and ID4, as miR342 target genes, was observed, accompanied by reduced expression of VEGF and Bcl2/Bax ratio at the protein level.

Conclusion

To conclude, our data support the idea that miR342 might be a potential therapeutic target for the treatment of triple-negative breast cancer (TNBC).