Controlled protein degradation mediated by ubiquitin/proteasome system (UPS) plays a crucial role in modulating a broad range of cellular responses. Dysregulation of the UPS often accompanies tumorigenesis and progression. Ubiquitination of a target protein involves a cascade of enzymes. Importantly, E3 ubiquitin ligases determine the specificity of protein substrates and are themselves the enzymes. They, therefore represent a group of attractive and potentially "drugable" molecular targets for disease intervention in mechanism driven drug discovery. My work is to identify the expression and activation status of Smurf2 (Smad ubiquitin regulatory factor 2), a HECT-type E3-ubiquitin ligase and the signaling pathways in which they are involved in breast cancer and to further investigate whether inhibition of Smurfs by either plant derived or synthetic drugs could be an effective therapeutic regime in breast cancer. We analyzed the expression of Smurf2 in 7 breast cancer cell lines and a high level expression of Smurf2 was detected in MDA-MB-231, NCI-ADR-RES and SKBR3 cell lines.

Cyclins and cyclin dependent kinases (cdks) regulate the cell division cycle in mammalian cells. The cyclin-cdk complex phosphorylates various cell cycle regulatory proteins which help in the progression of cells from one phase to another. On the other hand, cyclin dependant kinase inhibitors (CKIs) regulate various check points associated with cell division cycle. cks1 (cyclin dependent kinase subunit1) is one of the essential components of the cdks and has been found to be over-expressed in different human tumors. However, the exact role of its over-expression in cancers is still unclear. In addition to its role as an essential component of cyclin-cdk complexes, cks1 has also been known to function as an accessory protein of the SCF^Skp2 ubiquitinating machinery. Several studies in lower eukaryotes suggest cks1 to be essential for the cells during mitotic entry, progression and exit. Its close association with cdk1 has prompted us to investigate its role on cdk1 activation, a critical event during mitotic entry, progression and exit. Expression analysis of both cks1 and phospho-cdk1 was conducted in oral cancer cells upon re-entry into cell cycle from G1/S or G2/M phase synchronized stages. Its possible cross-talk with cyclin B has also been analyzed at both transcriptional and post transcriptional level. We observed a direct association of cks1 and cdk1 activation and ruled out a cross-talk between cyclin B and cks1. In conclusion, our results indicate that the functional role of cks1 during mitosis may be elicited at the level of cdk1 activation as well as at the level of associated events triggered by active cdk1.

Peroxisome Proliferator Activated Receptor gamma (PPAR Γ), a member of the nuclear receptor superfamily, is activated by several compounds, including the thiazolidinediones. Activation of PPAR Γ and regulation of gene transcription is a multistep process that involves ligand binding, heterodimerisation with retinoid X receptor (RXR), interaction with sequence specific gene promoter elements, and recruitment of coactivators and other nuclear coregulatory proteins. In addition to being a therapeutic target for obesity, hypolipidaemia and diabetes, perturbation of PPARΓ signaling is now believed to be a strategy for treatment of several cancers, including breast. In breast tissue, agonists of PPARΓ have been shown to inhibit cell growth, reduce estrogen production by adipose tissue, inhibit oestrogen receptor (ER) activity and play a role in tumor regression. As such, PPARΓ agonists have been proposed as anticancer therapeutics for breast cancer, a theory currently being tested in clinical trials. Although the therapeutic potential of PPARΓ agonists as anticancer agents is clearly evident, the role of PPARΓ activation in the process and thus their mechanism of action remains unclear. However, it is very much clear that there exist a link between PPARΓ and breast cancer and my work mainly focus on identifying the link, so that it can be used as a safe target in the management of breast cancer.

Stem cell biology is one of the most exciting research topics of today. There is increasing evidence that a rare population of undifferentiated cells is responsible for tumour formation and maintenance. It is likely that these undifferentiated cells undergo symmetric and asymmetric divisions in vivo, resulting in the expansion of the tumorigenic cell population while producing a progeny of more differentiated cells that constitute the prevalent population of the tumour cell mass. We aim to identify, isolate, and characterize the cancer stem cell (CSC) population that drives and maintains colorectal cancer growth and metastasis. We will also analyze whether established malignant colon cancer cell lines, which have been maintained for years in culture, contain a side population (SP) of stem cells and study its characteristics at the molecular level. The potential role of these tumor primordial cells in surgical margins will also be analyzed if any and correlated with the disease outcome. The stem cell profile in primary colorectal tumors/surgical margins will be compared with the prognosis of the patients and combination therapy targeted towards the suppression of these stem like cells will be analyzed.

Chronic myeloid leukemia (CML) has been regarded as the paradigmatic example of a malignancy defined by a unique molecular event, the BCR-ABL1 oncogene. CML is characterized by the Philadelphia (Ph) chromosome, which results from the t(9;22)(q34;q11) balanced reciprocal translocation. The molecular consequence of this translocation is the generation of the BCR-ABL1 oncogene that encodes the chimeric BCR-ABL1 protein with tyrosine kinase activity. The best known drug which is an inhibitor of the Bcr-Abl oncoprotein is Imatinib mesylate (IM), which has shown significant treatment responses, especially when applied during the early phases of CML. However, the cancer cells are evolving resistance to the drug, mainly through point mutations. Therefore, monotherapy with IM may not be the best option in CML. Addition of alternate TKIs which synergize with IM may enhance the effect of the targeted therapy. . This study aims at the synergistic anti-CML activity of IM with Indirubin, a Chinese anti-leukemia medicine, on IM-resistant and IM- sensitive conditions. The major expected outcome is the efficient reversal of imatinib resistance and effective cell killing via apoptosis. Nilotinib will be used as a positive control. This study may help identifying the exact molecular pathology behind imatinib resistance and help identifying new molecules to rectify the same. Moreover, the study may reveal new therapeutic approaches to halt imatinib resistance.

Signal Transducers and Activators of Transcription (STATs) are a family of cytoplasmic proteins with roles as signal messengers and transcription factors that participate in normal cellular responses to cytokines and growth factors. The oncogenic significance of activated STAT3 molecule is due to their effects on numerous parameters of the development and progression of malignancy, such as apoptosis, cell proliferation, angiogenesis and immune system evasion. In primary human breast tumor cells and human cancer cell lines, the cytokine IL-6 constitutively activates STAT3 molecule. Evaluation of the credibility of STAT3 as a valid molecular target for breast cancer therapy using cell cultures as well as whole animal models has met with positive outcomes. The discovery of the phenomenon of RNAi (RNA interference) has demonstrated that exogenously administered or artificially expressed double-stranded RNAs (dsRNAs) selectively inhibit expression of target genes with homologous nucleotide sequence. This approach of gene targeting, known as post-transcriptional gene-silencing, has been used in the development of si-RNA (short-interfering RNA)-based approaches in cancer therapy. The same approach would be undertaken to silence the STAT3 molecule and thereby used as a therapeutic approach for the treatment of breast cancer in combination with drugs used presently for its treatment. Inhibition of STAT3 signaling at the molecular level is proposed to provide improved treatment for breast cancer by overcoming chemoresistance.