Ram P. Tiwari

Biology of Cox-2: An Application in Cancer Therapeutics

Cyclooxygenase-2 (Cox-2) is an inducible enzyme involved in the conversion of arachidonic acid to prostaglandin and other eicosanoids. Molecular pathology studies have revealed that Cox-2 is over-expressed in cancer and stroma cells during tumor progression, and anti-cancer chemo-radiotherapies induce expression of Cox-2 in cancer cells. Elevated tumor Cox-2 is associated with increased angiogenesis, tumor invasion and promotion of tumor cell resistance to apoptosis. Several experimental and clinical studies have established potent anti-cancer activity of NSAID (Non-steroidal anti-inflammatory drugs) and other Cox-2 inhibitors such as celecoxib. Much attention is being focused on Cox-2 inhibitors as beneficial target for cancer chemotherapy. The mode of action of Cox-2 and its inhibitors remains unclear. Further clinical application needs to be investigated for comprehending Cox-2 biological functions and establishing it as an effective target in cancer therapy.

Down-regulation of survivin by oxaliplatin diminishes radioresistance of head and neck squamous carcinoma cells

BACKGROUND Oxaliplatin is integrated in treatment strategies against a variety of cancers including radiation protocols. Herein, as a new strategy we tested feasibility and rationale of oxaliplatin in combination with radiation to control proliferation of head and neck squamous cell carcinoma (HNSCC) cells and discussed survivin-related signaling and apoptosis induction. METHODS Cytotoxicity and apoptosis induced by radiation and/or oxaliplatin were examined in relation to survivin status using two HNSCC cell lines viz., Cal27 and NT8e, and one normal 293-cell line. Survivin gene knockdown by siRNA was also tested in relevance to oxaliplatin-mediated radiosensitization effects. RESULTS Survivin plays a critical role in mediating radiation-resistance in part through suppression of apoptosis via a caspase-dependent mechanism. Oxaliplatin treatment significantly decreased expression of survivin in cancer cells within 24-72 h. Apoptotic cells and caspase-3 activity were increased parallely with decrease in cell viability, if irradiated during this sensitive period. The cytotoxicity of oxaliplatin and radiation combination was greater than additive. Survivin gene knockdown experiments have demonstrated the role of survivin in radiosensitization of cancer cells mediated by oxaliplatin. CONCLUSIONS Higher expression of survivin is a critical factor for radioresistance in HNSCC cell lines. Pre-treatment of cancer cells with oxaliplatin significantly increased the radiosensitivity through induction of apoptosis by potently inhibiting survivin.

Detection of survivin and p53 in human oral cancer: Correlation with clinicopathologic findings

Survivin, an inhibitor of apoptosis, is overexpressed in cancer. It has been implicated in both prevention of apoptosis and cell cycle regulation. We investigated the distribution of antiapoptotic protein survivin in 29 oral squamous cell carcinoma (OSCC) and 16 oral premalignant lesions. It has been suggested that wild‐type p53 represses survivin expression. Therefore, we investigated the status of p53 in relation to survivin to determine the potential involvement in oral tumorigenesis.

Induction of Apoptosis and Sensitization of Head and Neck Squamous Carcinoma Cells to Cisplatin by Targeting Survivin Gene Expression

Survivin is known to be highly-expressed in various carcinomas; and is associated with their biologically aggressive characteristics and drug resistance. We have previously reported survivin as an important anti-apototic protein involved in head and neck squamous cell carcinoma (HNSCC) tumorigenesis and providing resistance to conventional cancer therapies. The purpose of present study was to investigate the potential of survivin as a therapeutic target in HNSCC. This study was designed to explore the effect(s) of survivin-siRNA therapy on the apoptosis in HNSCC cells, and its influence on cisplatin-sensitivity. Lentivirus vector was developed to deliver survivin specific siRNA into cancer cells. The data indicates that silencing of survivin-mediated by Lentivirus-siRNA therapy effectively suppressed cancer cell proliferation and induced caspase-dependent apoptosis in HNSCC cells. The study also shows that the response of HNSCC cells to cisplatin drug treatment at clinically relevant level was limited. We observed survivin to be a key factor involved in this cisplatin-resistance mechanism, and down-regulation of survivin significantly increased sensitivity of cancer cells to cisplatin-mediated apoptosis. Thus, this combination therapy acts as a multimodality regimen with significant potential to improve clinical outcomes in head and neck cancers.

Cardiac Troponins I and T: Molecular Markers for Early Diagnosis, Prognosis, and Accurate Triaging of Patients with Acute Myocardial Infarction

Acute myocardial infarction (AMI) is the leading cause of death worldwide, with early diagnosis still being difficult. Promising new cardiac biomarkers such as troponins and creatine kinase (CK) isoforms are being studied and integrated into clinical practice for early diagnosis of AMI. The cardiac-specific troponins I and T (cTnI and cTnT) have good sensitivity and specificity as indicators of myocardial necrosis and are superior to CK and its MB isoenzyme (CK-MB) in this regard. Besides being potential biologic markers, cardiac troponins also provide significant prognostic information. The introduction of novel high-sensitivity troponin assays has enabled more sensitive and timely diagnosis or exclusion of acute coronary syndromes. This review summarizes the available information on the potential of troponins and other cardiac markers in early diagnosis and prognosis of AMI, and provides perspectives on future diagnostic approaches to AMI.

Glycolipids of Mycobacterium tuberculosis Strain H37Rv Are Potential Serological Markers for Diagnosis of Active Tuberculosis

ABSTRACT A simple and cost-effective diagnostic tool (TB Screen Test) for the screening of patients with pulmonary and extrapulmonary tuberculosis and for differentiation of those individuals from individuals without tuberculosis, other common infections, and healthy controls has been developed. The serological responses of purified mycobacterial glycolipid antigens were examined by a liposome agglutination assay. The assay was able to detect very low antiglycolipid antibody concentrations in the infected individuals. The sera from the tuberculosis patient group had significantly higher concentrations of antiglycolipid antibody than the sera from uninfected control subjects, with 94% sensitivity and 98.3% specificity. Glycolipids of Mycobacterium tuberculosis H37Rv antigens were isolated, purified, and characterized. After interchelation with liposome particles, these purified antigens specifically bound to the antiglycolipid antibodies present in the sera of patients with tuberculosis, resulting in the formation of a blue agglutination. This protocol clearly differentiates healthy controls and M. bovis BCG-vaccinated subjects from those with active tuberculosis. The resultant diagnostic tool, the TB Screen Test, is more economical and rapid (4 min) than other currently available products and can be used for the mass screening of a heavily afflicted population.

Growth inhibition and chemo-radiosensitization of head and neck squamous cell carcinoma (HNSCC) by survivin-siRNA lentivirus.

BACKGROUND Survivin expression is often associated with aggressive tumor behavior and therapy resistance. In this study, we investigated the effect of survivin knockdown by survivin-siRNA lentiviral vector (Svv-Lent) on the response of HNSCC to chemo-radiotherapy, tumor growth and metastasis. METHODS Four human HNSCC (OSC19, Cal27, Cal33 and FaDu) and one normal HOK cell lines were included in the study, and survivin knockdown was achieved with Svv-Lent treatment. Cell proliferation and apoptosis were measured by MTT and TUNEL assay, respectively. Transwell assays were performed to measure in vitro cell migration and matrigel invasion. Xenograft tumors were developed in nude mice by injecting Cal27 cells subcutaneously and following tail-vein injection of lung and liver metastasis. RESULTS Knockdown of survivin significantly suppressed HNSCC cell proliferation and induced apoptosis in vitro. Survivin inhibition could also significantly reduce in vitro cell migration and matrigel invasion that might be due to inactivation of matrix metalloproteinases. In vivo studies showed significant repression of Cal27 xenograft tumor growth and tissue metastasis leading to improvement in mice survival in the Svv-Lent treated group compared to controls. Our data indicated that survivin expression in HNSCC cells contributed to chemo-radioresistance, and its down-regulation increased anti-cancer effects of paclitaxel, cisplatin and radiation. CONCLUSIONS Our findings suggest that sustained survivin expression facilitates HNSCC tumor growth and confers resistance to chemo-radiotherapy. Svv-Lent therapy may be able to enhance the cytotoxic effect of commonly used anticancer drugs such as cisplatin and paclitaxel, and radiotherapy that could provide a promising strategy for the effective control of resistant head and neck cancer.

Allele mining in β-lactoglobulin gene of Capra hircus

β-Lactoglobulin (β-LG) genetic polymorphisms are important and well known due to their effects on quantitative traits and technological properties of milk. At the DNA level, polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) allows for the detection of unknown polymorphisms at β-LG loci. Here we describe the usefulness of the PCR-SSCP technique for β-LG typing. In the present study, we amplified and sequenced the part of promoter region and all the seven exons containing the entire coding and untranslated region for the β-lactoglobulin gene in best dairy goat breeds of India namely: Jamunapari and Jakhrana. Nine polymorphisms were detected, one in the l promoter region, four in the introns and four in the exons of the β-lactoglobulin gene. All polymorphisms were single nucleotide substitutions. The polymorphisms in the coding region did not produce any amino acid change.

Oncoapoptotic Markers in Oral Cancer: Prognostics and Therapeutic Perspective

Oral cancer is one of the most commonly found cancers in many South-Asian underdeveloped countries, especially among men in comparison to women. When considering the mortality rate among all types of existing cancers, in India oral cancer is the primary reason for death in men. Some of the major reasons contributing to the high mortality rate are late diagnosis, lack of treatment options and high prevalence of tobacco consumption. Oral cancer is often diagnosed at a stage when cancer cells have already become aggressive and become resistant to standard therapeutic options. Progression, apoptosis, angiogenesis, metastasis and invasion behold great capability to treat and detect cancer at the molecular level. Dysregulation of apoptosis is one of the most common molecular events known to be associated with the development of oral cancer. In this review, we discuss key apoptotic markers which can be used as prognostic and/or therapeutic targets in oral cancer.