Reversing Anoikis Resistance in Triple-Negative Breast Cancer.

摘要

During the first year of this idea expansion grant, we have addressed Aim1, which was to determine if restoration of miR-200c and inhibition of miR-222 can enhance TNBC differentiation in 3D culture. We found addition of miR-200c and miR-222 inhibition make TNBC colonies in culture in 3D in matrigel smaller, rounder and increase Dicer protein. Additionally, restoration of miR-200c decreases the amount of xCT protein, which regulates intracellular glutathione levels). There are multiple predicted target sites for both miR-200c and miR-193 in the xCT 3 UTR so we are cloning this region to prove that it is a direct target of these miRNA since miR-200c is lost in TNBC that are anoikis resistant and miR-193b decreases in suspension. We also find that restoration of miR-200c increases epithelial splicing factors in TNBC. In this first year we have also completed tasks in Aim 2 to identify the mechanisms by which TNBC cells resist anoikis. We confirmed that TNBC regulators of reactive oxygen species such as xCT and stress and inflammatory pathway genes including COX2 in suspension. Lastly, we followed up on our observation that components of the kynurenine pathway (KP), that leads to formation of NAD(+) increases in suspension. We demonstrate that knockdown of COX2 increases death in suspension as does knockdown or inhibition of TDO2. Our study continues to generate mechanistic and pre-clinical data necessary to determine if manipulation of key miRNAs has potential as a form of differentiation therapy for TNBC, for which there is currently no effective targeted treatment.