ßhCG mediates immune suppression through upregulation of CD11b+ Gr1+ myeloid derived suppressor cells, CD206+ M2 macrophages, and CD4+ FOXP3+ regulatory T-cells in BRCA1 deficient breast cancers.

BRCA1 mutation is reported in about 70% of all triple negative breast cancers (TNBC), while BRCA1 defect due to promoter hypermethylation is seen in about 30%-60% of sporadic breast cancers. Although PARP inhibitors and platinum-based chemotherapy are used to treat these cancers, more efficient therapeutic approaches are required to overcome the resistance to treatment. Our previous findings have reported elevated ßhCG expression but not αhCG in BRCA1 deficient breast cancers. As ßhCG causes immune suppression in pregnancy, this study explored the immunomodulatory effect of ßhCG in BRCA1mutated/deficient TNBC. We observed that Th1, Th2, and Th17 cytokines are upregulated in the presence of ßhCG in BRCA1 defective cancers. In NOD-SCID and syngeneic mouse models, ßhCG increases the frequency of Myeloid-derived suppressor cells in tumour tissues and contributes to macrophage reprogramming from antitumor M1 to pro-tumour M2 phenotype. ßhCG reduces the CD4+ T-cell infiltration while increasing the density of CD4+ CD25+ FOXP3+ regulatory T-cell in BRCA1 deficient tumour tissues. In contrast, xenograft tumours with ßhCG knocked down TNBC cells did not show these immune suppressive effects. We have also shown that ßhCG upregulates pro-tumorigenic markers arginase1(Arg1), inducible nitric oxide synthase, PD-L1/PD-1, and NFκB in BRCA1 defective tumours. Thus, for the first time, this study proves that ßhCG suppresses the host antitumor immune response and contributes to tumour progression in BRCA1 deficient tumours. This study will help develop new immunotherapeutic approaches for treating BRCA1 defective TNBC by regulating ßhCG.

BRCA1 promoter hypermethylation in human placenta: a hidden link with ß-hCG expression.

Gestational trophoblastic diseases (GTD) are group of pregnancy-related tumors characterized by abnormal levels of 'ß-hCG' with higher incidence in South-East Asia, especially India. Our laboratory has reported that wild-type BRCA1 transcriptionally regulates ß-hCG in triple negative breast cancers (TNBCs). These factors culminated into analysis of BRCA1 status in GTD, which would emanate into elucidation of BRCA1- ß-hCG relationship and unraveling etio-pathology of GTD. BRCA1 level in GTD is down-regulated due to the over-expression of DNMT3b and subsequent promoter hypermethylation, when compared to the normal placentae accompanied with its shift in localization. There is an inverse correlation of serum ß-hCG levels with BRCA1 mRNA expression. The effects of methotrexate (MTX), which is the first-line chemotherapeutic used for GTD treatment, when analyzed in comparison with plumbagin (PB) revealed that PB alone is efficient than MTX alone or MTX-PB in combination, in showing selective cytotoxicity against GTD. Interestingly, PB increases BRCA1 levels post-treatment, altering DNMT3b levels and resultant BRCA1 promoter methylation. Also, cohort study analyzed the incidence of GTD at Sree Avittom Thirunal (SAT) Hospital, Thiruvananthapuram, which points out that 11.5% of gestational trophoblastic neoplasia (GTN) cases were referred to Regional Cancer Centre, Thiruvananthapuram, for examination of breast lumps. This has lend clues to supervene the risk of GTD patients towards BRCA1-associated diseases and unveil novel therapeutic for GTD, a plant-derived naphthoquinone, PB, already reported as selectively cytotoxic against BRCA1 defective tumors.

Gene expression signatures: A tool for analysis of breast cancer prognosis and therapy.

Breast Cancer is the most predominant female cancer in developed as well as developing countries. The treatment strategies of breast cancers depends on an array of factors like age at diagnosis, menstrual status, dietary pattern, immunological response, genetic variations of the cancer cells etc. Recent technological advancements in cancer diagnosis lead to the emergence of gene expression pattern for better understanding of the tumor behavior. It has not only bolstered the prognosis, but also the early diagnosis and therapy. The accuracy in disease prognosis can be boosted when gene expression signatures are combined with traditional clinicopathological features. This review explains how the evolution of gene expression signatures for breast cancers, its advantages and future prospects. In addition, an overview of currently available gene expression signature analysis tools and consolidated information on their current status and specific benefits, that can be availed for breast cancer diagnosis are also discussed.

Brcal Defective Breast Cancer Cells Induce in vitro Transformation of Cancer Associated Fibroblasts (CAFs) to Metastasis Associated Fibroblasts (MAF).

It is known that Cancer Associated Fibroblast (CAFs) from the primary tumor site can accompany cancer cells to a secondary site during the process of metastasis. We hypothesize that these CAFs could be transformed to an altered cell type, which can be called as Metastasis Associated Fibroblasts (MAF) in turn can support, and convoy cancer cells for metastasis. There are no published reports that have characterized and distinguished CAFs from MAF. It is well established that some of the cancer cells within the tumor mass accumulate novel mutations prior to metastasis. Hence, we speculated that mutations in the tumor suppressor gene, BRCA1, which is already reported to induce metastasis via abnormal expression of Ezrin, Radixin and Moesin (ERM), could generate MAF. In the present study, we demonstrate for the first time that CAFs isolated from primary breast cancer tissues when co-cultured with BRCA1 mutated HCC1937 cells transform CAFs to MAF in vitro. As expected, MAF augmented proliferation, migration and invasion along with over-expression of epithelial mesenchymal transition (EMT) markers, Ezrin and CCL5, thereby facilitating metastasis. Therefore, we inhibited Ezrin and CCL5 in vitro in MAF and observed that the migration and invasion abilities of these cells were attenuated. This highlights the intriguing possibilities of combination therapy using MAF inhibitors as anti-metastatic agents along with anticancer drugs, to control the metastatic spread from primary tumor site.

Insights into dovetailing GTD and Cancers.

Gestational trophoblastic diseases (GTD) encompass a group of placental tumors which mostly arise due to certain fertilization defects, resulting in the over-proliferation of trophoblasts. The major characteristic of this diseased state is that ß-hCG rises up manifold than that is observed during pregnancy. The incidence of GTD when analyzed on a global scale, figures out that there is a greater risk in South-East Asia, the reason of which remains unclear. An insight into any possible correlation of GTD incidence with cancers, other than choriocarcinoma, is being attempted here. Also, we review the recent developments in research on the molecular etiopathology of GTD. This review would render a wider eye towards a new paradigm of thoughts to connect GTD and breast cancer, which has not been into the picture till date.