FOXO1 promotes the expression of canonical WNT target genes in examined basal-like breast and glioblastoma multiforme cancer cells

Basal-like breast cancer (BBC) and glioblastoma multiforme (GBM) are aggressive cancers associated with poor prognosis. BBC and GBM have stem cell-like gene expression signatures, which are in part driven by forkhead box O (FOXO) transcription factors. To gain further insight into the impact of FOXO1 in BBC, we treated BT549 cells with AS1842856 and performed RNA sequencing. AS1842856 binds to unphosphorylated FOXO1 and inhibits its ability to directly bind to DNA. Gene Set Enrichment Analysis indicated that a set of WNT pathway target genes, including lymphoid enhancer-binding factor 1 (LEF1) and transcription factor 7 (TCF7), were robustly induced after AS1842856 treatment. These same genes were also induced in GBM cell lines U87MG, LN18, LN229, A172, and DBTRG upon AS1842856 treatment. By contrast, follow-up RNA interference (RNAi) targeting of FOXO1 led to reduced LEF1 and TCF7 gene expression in BT549 and U87MG cells. In agreement with RNAi experiments, CRISPR Cas9-mediated FOXO1 disruption reduced the expression of canonical WNT genes LEF1 and TCF7 in U87MG cells. The loss of TCF7 gene expression in FOXO1 disruption mutants was restored by exogenous expression of the DNA-binding-deficient FOXO1-H215R. Therefore, FOXO1 induces TCF7 in a DNA-binding-independent manner, similar to other published FOXO1-activated genes such as TCF4 and hes family bHLH transcription factor 1. Our work demonstrates that FOXO1 promotes canonical WNT gene expression in examined BBC and GBM cells, similar to results found in Drosophila melanogaster, T-cell development, and murine acute myeloid leukemia models.

Clinicopathological Features and Treatment Challenges in Triple Negative Breast Cancer Patients: A Retrospective Cohort Study

OBJECTIVE

As the genetic and molecular profiles of triple negative breast carcinoma (TNBC) are elucidated, multiple therapeutic targets have been produced. TNBC with less than 1% androgen receptor (AR) expression may respond to enzalutamide with greater response association in higher levels. A metronomic dose of capecitabine and docetaxel are effective developed drugs for angiogenic process inhibition. We aimed to demonstrate the treatment outcome of triple-negative breast cancer patients in correlation to their clinicopathological features.

MATERIALS AND METHODS

A retrospective cohort study of 80 TNBC patients was conducted. The patients underwent proper observation with the reporting of their treatment and follow-up data. Patients with a metastatic disease, neoadjuvant chemotherapy, follow-up drop or data shortage were excluded from the survival analysis.

RESULTS

The study results revealed a significant association between negative androgen expression and younger age ≤35 years, premenopausal status, higher grade, extracapsular extension, lymphovascular invasion, Ki 67, and CA15-3 (p=0.003, 0.02, < 0.001, 0.001, 0.027, 0.005, 0.009 respectively). The three-year overall survival (OS) in patients who received bicalutamide was better than those patients who received capecitabine or docetaxel but of no significance (p=0.46). The three-year disease free survival (DFS) was significantly better in the bicalutamide arm versus the other two groups (p=0.012).

CONCLUSIONS

We concluded that extended adjuvant antiandrogen such as bicalutamide and metronomic capecitabine are well tolerated with accepted compliance and affordability compared to docetaxel and are warranted for problem-solving and better DFS and OS in some TNBC patients.

MiR-195 regulates mitochondrial function by targeting mitofusin-2 in breast cancer cells

Mitochondrial dynamics is a highly dysregulated process in cancer. Apoptosis and mitochondrial fission are two concurrent events wherein increased mitochondrial fragmentation serves as a hallmark of apoptosis. We have shown earlier that miR-195 exerts pro-apoptotic effects in breast cancer cells. Herein, we have demonstrated miR-195 as a modulator of mitochondrial dynamics and function. Imaging experiments upon miR-195 treatment have shown that mitochondria undergo extensive fission. We validated mitofusin2 as a potential target of miR-195. This may provide a molecular explanation for the respiratory defects induced by miR-195 over-expression in breast cancer cells. Active, but not total, mitochondrial mass, was reduced with increasing levels of miR-195. We have further shown that miR-195 enhances mitochondrial SOD-2 expression but does not affect PINK1 levels in breast cancer cells. Collectively, we have revealed that miR-195 is a modulator of mitochondrial dynamics by targeting MFN2 thereby impairing mitochondrial function. Concomitantly, it enhances the scavenger of reactive oxygen species (SOD-2) to maintain moderate levels of oxidative stress. Our findings suggest a therapeutic potential of miR-195 in both ER-positive as well as ER-negative breast cancer cells.

Geminin overexpression promotes imatinib sensitive breast cancer: a novel treatment approach for aggressive breast cancers, including a subset of triple negative

Breast cancer is the second leading cause of cancer-related deaths in women. Triple negative breast cancer (TNBC) is an aggressive subtype that affects 10–25% mostly African American women. TNBC has the poorest prognosis of all subtypes with rapid progression leading to mortality in younger patients. So far, there is no targeted treatment for TNBC. To that end, here we show that c-Abl is one of several tyrosine kinases that phosphorylate and activate geminin’s ability to promote TNBC. Analysis of >800 breast tumor samples showed that geminin is overexpressed in ∼50% of all tumors. Although c-Abl is overexpressed in ∼90% of all tumors, it is only nuclear in geminin overexpressing tumors. In geminin-negative tumors, c-Abl is only cytoplasmic. Inhibiting c-Abl expression or activity (using imatinib or nilotinib) prevented geminin Y150 phosphorylation, inactivated the protein, and most importantly converted overexpressed geminin from an oncogene to an apoptosis inducer. In pre-clinical orthotopic breast tumor models, geminin-overexpressing cells developed aneuploid and invasive tumors, which were suppressed when c-Abl expression was blocked. Moreover, established geminin overexpressing orthotopic tumors regressed when treated with imatinib or nilotinib. Our studies support imatinib/nilotonib as a novel treatment option for patients with aggressive breast cancer (including a subset of TNBCs)-overexpressing geminin and nuclear c-Abl.

The addition of bevacizumab to standard chemotherapy in breast cancer: which patient benefits the most?

Bevacizumab, a humanized monoclonal antibody directed against vascular endothelial growth factor, is an effective and well-tolerated treatment option for patients with breast cancer. Bevacizumab has demonstrated a gain in progression-free survival and a trend towards an overall survival benefit in various subgroups of breast cancer. Given the lack of a predictive biomarker, we performed a literature search with regard to efficacy and tolerability of bevacizumab in different subgroups of breast cancer patients and in different settings. In the metastatic setting, the efficacy of bevacizumab has been most extensively studied and demonstrated in patients with triple-negative breast cancer, the most difficult-to-treat population among patients with advanced disease and also the group with the biggest need for new treatment options. Overall, bevacizumab is well tolerated with very few serious adverse events. Bevacizumab is also an active and feasible treatment option for patients above 70 years of age.

Race and the prognostic influence of p53 in women with breast cancer

BACKGROUND

Prior study suggests that p53 status behaves as an independent marker of prognosis in African American (AA) women with breast cancer. We investigate whether the influence of p53 is unique to AAs or is present in other race/ethnic groups, and how this compares with known prognostic factors.

METHODS

Cox regression models [hazard ratios (HRs), 95% confidence intervals (CIs)] were used to select and evaluate factors prognostic for all-cause mortality in 331 AA and 203 non-AA consecutively treated women.

RESULTS

Statistically significant baseline prognostic factors were as follows. For AAs: stage [(III/I) HR 5.57; 95% CI 3.08-10.09], grade [(higher/low) HR 1.55; 95% CI 1.14-2.11], estrogen receptor (ER)/progesterone receptor (PR) status [(-/+) HR 2.01; 95% CI 1.38-2.93], triple negative (ER-, PR-, HER2-) subtype [(+/-) HR 1.95; 95% CI 1.33-2.85], and p53 status [(+/-) HR 1.69; 95% CI 1.10-2.58]. For non-AAs: stage [HR 11.93; 95% CI 2.80-50.84], grade [HR 1.61; 95% CI 0.96-2.71], and ER/PR status [HR 2.13; 95% CI 1.19-3.81]. There was a differential effect of race within p53 groups (P=0.05) and in multivariate modeling p53-positive status remained an adverse prognostic factor in AAs only [HR 1.82; 95% CI 1.04-3.17]. Compared to non-AAs, 5-year unadjusted survival was worse for AAs overall (73.4% vs. 63.6%; P=0.032), and also for AAs with p53-positive status (80.3% vs. 54.2%; P=0.016), but not for AAs with p53-negative disease (68.4% vs. 67.9%; P=0.81).

CONCLUSIONS

Among women with breast cancer of different race/ethnicity, an adverse prognostic effect as a result of p53 positivity was only observed in AA women.