Trupti Patel

From Natural Products to Drugs for Epimutation Computer-Aided Drug Design

The epimutational event, i.e., ectopic methylation in tumor suppressor genes, can lead to gene silencing, thus promoting prognosis of cancer. The progression of DNA methylation is a cycle of demethylation, de novo methylation, and maintenance methylation. The enzyme responsible for maintenance of methylation status is DNA methyltransferase 1 (DNMT1), the continuous activity of which is required to maintain the pattern of epimutation; thus, its inhibition is a promising strategy for the treatment of cancer. To the best of our knowledge, this study is the first to focus on the recently developed crystal structure of the catalytic site of DNMT1. Here in this study, we have used the crystal structure for the development of non-nucleoside DNMT1 inhibitors using virtual screening (VS), absorption, distribution, metabolism, elimination/toxicology analysis, and molecular docking studies. In this study, VS was carried out on 48,531 natural products to create a subset of lead-like natural products. Three of them were found to form hydrogen bonds with the catalytic site of the DNMT1 (Cys 1226). Thus, this study adumbrates potential lead compounds for treatment of epimutation.

Study of cytomorphology of solid pseudopapillary tumor of pancreas and its differential diagnosis.

Background: Solid pseudopapillary tumor is a rare pancreatic neoplasm with uncertain to low malignant potential. This is an uncommon neoplasm with many pseudonyms, occurring predominantly in young woman under the age of thirty years. Aims: To study the cytomorphological features of six cases of solid and pseudopapillary epithelial neoplasm of pancreas diagnosed on fine needle aspiration cytology (FNAC) in years 2005 to 2007 and its cyto-histological correlation. Materials and Methods: Image-guided FNAs was done in these six patients preoperatively. Alcohol-fixed smears were stained with Papanicolaou stain, cytomorphological findings were evaluated and diagnosis was made. Diagnosis was later confirmed by histology in all cases. Results: All six cases show characteristic cytological features such as hypercellular smears with presence of abundant delicate papillary fragments, dyscohesive cells, monomorphic tumor cells with delicate folded nuclear membranes, and foamy macrophages in the background. Conclusions: Preoperative correct diagnosis of solid pseudopapillary tumor of pancreas is possible on FNAC and by doing so it helps in management of this surgically curable neoplasm.

N-Nitrosodimethylamine in the Kashmiri Diet and Possible Roles in the High Incidence of Gastrointestinal Cancers

The Kashmiri population is culturally distinct with special dietary features owing to the temperate climatic conditions of Kashmir valley. This has habituated the population to preserve food in smoked, pickled and sundried forms which include considerable amounts of N-nitroso compounds (NOCs). These are known to cause cytotoxicity, DNA damage, mutation, unscheduled DNA synthesis and DNA methylation. All of these changes at molecular level are known to contribute to the pathogenesis of cancer. One of the prominent NOCs found in Kashmiri food is N-Nitrosodimethylamine (NDMA). Here we review the occurrence of NDMA in sundried foods, dried fish, kehwa, traditional pickle, Brassica oleracia and tobbaco. We also discuss its possible role in the high prevalence of gastrointestinal cancers in Kashmir.

Pathological predictive factors for tumor response in locally advanced breast carcinomas treated with anthracyclin-based neoadjuvant chemotherapy

AIM Neoadjuvant chemotherapy (NACT) is used as a primary treatment for locally advanced breast carcinoma (LABC) and also extended to operable breast cancer. The aim of this study was to evaluate the predictive value of different histological parameters in core biopsy of LABC patients treated with anthracycline-based chemotherapy regimen. Pathological assessment of the excised tumor bed is the gold standard and is essential for identifying the group of patients with pathologic complete response (pCR) or pathologic noncomplete response (pNR). MATERIALS AND METHODS A total of 50 patients with stage II and III breast carcinoma were included in the study. Pretreatment core biopsy histological features include tumor type, histological grade, presence of tumor necrosis, lymphovascular emboli (LVE) and immunohistochemical stains for estrogen receptor (ER) and progesterone receptor (PR) were obtained. Patients were given 3-6 cycles of NACT. Pathological response was assessed. RESULT Seven out of 50 patients achieved pCR. A total of 71.4% patients who achieved pCR had tumor necrosis on initial core biopsy while only 30% pNR cases had this feature (P =0.035). Breast carcinoma other than ductal type was chemoresistant. Of 47 core biopsies, LVE was observed in 13 cases (28 %) of which 11 showed axillary node metastasis. None of these 13 cases had pCR, thus having poor predictive value. CONCLUSION Pathological parameters like type of tumor, presence of LVE and tumor necrosis in the core biopsy can predict the response to NACT in routine stain. Tumor necrosis and type of breast carcinoma are predictive parameters for tumor responsiveness to NACT. LVE was reliable in predicting axillary lymph node metastasis.

Gut microbiota: an Indicator to Gastrointestinal Tract Diseases

PurposeGut microbiota is predicted to play a key role in manifestation of gastrointestinal tract cancers. The human gastrointestinal tract is a complex and abundant network of microbial community. Gut microbiota depicts the microbe population living in our intestine. Humans harbour more than 1014 microbes in the gut, and the diversity and densities of the microbiota increase from stomach to colon.MethodsThe beneficial relationship between endogenous microbiota and the eukaryotic hosts helps in maintaining various metabolic activities of the body as well as temperature and pH balance. Studies using culturing methods have suggested that the oesophagus is either sterile or contains only a few transient microbes that originates from the oropharynx by swallowing or from the stomach by gastroesophageal reflux. However, metagenomics suggest that large numbers of uncultured organisms are harboured in the human gut.ResultsObservations suggest that research directed towards manipulation of the gut microbiota can be employed in prevention as well as treatment of these conditions. Well-designed, randomized, placebo-controlled human studies using probiotics and/or prebiotics are necessary to formulate the directions for prevention and therapy.ConclusionsChange in gut microbes in gastrointestinal (GI) tract may have major implication in gastric cancer, the fifth most occurring malignancy in the world. Affected population manifests multiple conditions and diseases, which majorly includes inflammatory bowel disease and colorectal malignancy.

Atomic Insight into the Altered O6-Methylguanine-DNA Methyltransferase Protein Architecture in Gastric Cancer.

O6-methylguanine-DNA methyltransferase (MGMT) is one of the major DNA repair protein that counteracts the alkalyting agent-induced DNA damage by replacing O6-methylguanine (mutagenic lesion) back to guanine, eventually suppressing the mismatch errors and double strand crosslinks. Exonic alterations in the form of nucleotide polymorphism may result in altered protein structure that in turn can lead to the loss of function. In the present study, we focused on the population feared for high exposure to alkylating agents owing to their typical and specialized dietary habits. To this end, gastric cancer patients pooled out from the population were selected for the mutational screening of a specific error prone region of MGMT gene. We found that nearly 40% of the studied neoplastic samples harbored missense mutation at codon151 resulting into Serine to Isoleucine variation. This variation resulted in bringing about the structural disorder, subsequently ensuing into a major stoichiometric variance in recognition domain, substrate binding and selectivity loop of the active site of the MGMT protein, as observed under virtual microscope of molecular dynamics simulation (MDS). The atomic insight into MGMT protein by computational approach showed a significant change in the intra molecular hydrogen bond pattern, thus leading to the observed structural anomalies. To further examine the mutational implications on regulatory plugs of MGMT that holds the protein in a DNA-Binding position, a MDS based analysis was carried out on, all known physically interacting amino acids essentially clustered into groups based on their position and function. The results generated by physical-functional clustering of protein indicated that the identified mutation in the vicinity of the active site of MGMT protein causes the local and global destabilization of a protein by either eliminating the stabilizing salt bridges in cluster C3, C4, and C5 or by locally destabilizing the “protein stabilizing hing” mapped on C3-C4 cluster, preceding the active site.

Metastatic appendiceal goblet cell carcinoid masquerading as mucinous adenocarcinoma in effusion cytology: A diagnostic pitfall

Goblet cell carcinoids are rare tumors of appendix having a mixed phenotype, with partial neuroendocrine differentiation and intestinal type goblet cell morphology. The reported incidence of this tumor is still limited. Till now, only two cases of metastatic goblet cell appendiceal carcinoid on effusion cytology have been reported in literature. We describe the clinico-pathological details and lay stress on fluid cytology of metastatic goblet cell carcinoid to ascitic fluid.

Granulosa cell tumor arising in an ovary with mature teratoma

Granulosa cell tumor (GCT) with synchronous mature teratoma is extremely rare and only eight cases are documented in the literature. GCT is low-grade malignancy and need a close follow up for recurrences which may be late. We report a case of GCT and mature teratoma occurring synchronously in the same ovary in a perimenopausal woman.

Pharmacological evaluation of phytochemicals from South Indian Black Turmeric (Curcuma caesia Roxb.) to target cancer apoptosis

Curcuma caesia Roxb. (Black turmeric), a perennial herb of the family Zingiberaceae is indigenous to India. C. caesia is used as a spice, food preservative and coloring agent commonly in the Indian subcontinent. Functional parametric pharmacological evaluations like drug ability and toxicity profile of this endangered species is poorly documented. In our present study, among all the extracts of dried C. caesia rhizome viz- hexane, ethyl acetate, methanol and water tested for free radical scavenging capacity by total antioxidant activity (TAO) method, Hexane Rhizome Extract (HRE) was found to possess remarkable activity (1200mg ascorbic acid equivalent/100g). In MTT assay across three cancer cell lines and a control cell line, HRE exhibited a dose-dependent inhibition only in cancer cells, with notable activity in HepG2 cell lines (IC50: 0976µg/mL). Further, western blotting and flow cytometry experiments proved that HRE induces cell arrest at G2/M phase along with cellular apoptosis as suggestive by multiple-point mitochondrial mediated intrinsic pathway of Programmed Cell Death (PCD). Gas Chromatography-Mass Spectrophotometry (GC-MS) analysis of HRE suggested twenty compounds that when docked in silico with Tubulin (1SA0) and Epidermal Growth Factor Receptor/ EGFR (1XKK) showed very intimate binding with the original ligands. Our results provided significant evidence of the toxicity mechanisms of HRE that may be beneficial for more rational applications of drug discovery for slowing down cancer progression.

Osteoid differentiation in mesodermal (mullerian) adenosarcoma of ovary.

A 55-year-old female presented with abdominal pain and 10 cm mass per abdominal examination. Computerized tomography scan of abdomen and pelvis revealed a heterogeneously enhancing solid cystic mass right ovarian mass and mild ascites. Surgery was performed. Specimens were sent for examination. Microscopic examination revealed an admixture of benign but occasionally atypical appearing mullerian type glands with sarcomatous stroma. Solid area showed undifferentiated tumour cells. Atypical mitoses and necrosis were also seen. Areas with extensive benign osteoid surrounded by fibroblastic stroma were also present. Glandular component showed positivity for CK-7, AE-1 and EMA while sarcomatous areas showed positivity for vimentin only. Mullerian adenosarcoma of ovary with sarcomatous overgrowth (SO) having heterologous component was confirmed. Postoperative 3 cycles of chemotherapy was given and the patient was well till date (three months after surgery).