Potential of adjunctive Mycobacterium w (MIP) immunotherapy in reducing the duration of standard chemotherapy against tuberculosis.

INTRODUCTION: The need to shorten the treatment duration in tuberculosis has always been felt. Immunotherapy in combination with chemotherapy has been considered a promising approach for this purpose into tuberculosis. We studied the adjuvant immunotherapeutic activity of Mycobacterium indicus pranii (MIP or Mw) in combination with conventional chemotherapy using guinea pig of pulmonary tuberculosis infected with Mycobacterium tuberculosis H37Rv via aerosol. METHODS: Experimental animals treated with standard chemotherapy and immunotherapy (MIP) separately and in combination of both. Guinea pig lungs evaluated following infection and subsequent therapy at predefine time point. Various cytokine mRNA expressions levels were quantified by quantitative reverse transcriptase PCR at the 4th, 8th and 12th week post-infection of M. tuberculosis. RESULTS: We determined the time required for bacterial clearance from guinea pig lungs. Standard chemotherapy (RvCh) compared to the animals where chemotherapy plus Mw immunotherpay (RvChMwT) was given. It took 12 weeks to achieve bacterial clearance in the RvCh group while this was achieved in 8 weeks in RvChMwT group. Pro-inflammatory cytokines (IFN-γ, IL-2, IL-12p35 and TNF-α) level were higher in RvCh, RvChMwT and RvMwT group, while the IL-10 and TGF-ß were suppressed. CONCLUSION: Cytokine expression level showed that Mw in conjunction with chemotherapy enhances the effect of pro-inflammatory cytokines (such as, IFN-γ, IL-2, IL-12 and TNF-α) and reduces the production and effect of anti-inflammatory cytokines (like IL-10 and TGF-ß) thereby restoring the pro-inflammatory / anti-inflammatory cytokines balance. Thus, the present study indicates that subject to rigorous testing by other parameters, Mw (MIP) as adjunct immunotherapy has potential for reducing treatment duration.

Survivin, a molecular target for therapeutic interventions in squamous cell carcinoma.

Squamous cell carcinoma (SCC) is the most common cancer worldwide. The treatment of locally advanced disease generally requires various combinations of radiotherapy, surgery, and systemic therapy. Despite aggressive multimodal treatment, most of the patients relapse. Identification of molecules that sustain cancer cell growth and survival has made molecular targeting a feasible therapeutic strategy. Survivin is a member of the Inhibitor of Apoptosis Protein (IAP) family, which is overexpressed in most of the malignancies including SCC and totally absent in most of the normal tissues. This feature makes survivin an ideal target for cancer therapy. It orchestrates several important mechanisms to support cancer cell survival including inhibition of apoptosis and regulation of cell division. Overexpression of survivin in tumors is also associated with poor prognosis, aggressive tumor behavior, resistance to therapy, and high tumor recurrence. Various strategies have been developed to target survivin expression in cancer cells, and their effects on apoptosis induction and tumor growth attenuation have been demonstrated. In this review, we discuss recent advances in therapeutic potential of survivin in cancer treatment.

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.

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.

Parasite killing in malaria non-vector mosquito Anopheles culicifacies species B: implication of nitric oxide synthase upregulation.

BACKGROUND: Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. CONCLUSIONS/SIGNIFICANCE: We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and could be utilized to understand the molecular basis of refractoriness in planning effective vector control strategies.

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

BACKGROUND: 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. METHODS: Oral cancer tissues were freshly obtained at the time of surgery and classified as per general rules of head and neck cancer (TNM classification). Immunohistochemistry and reverse transcriptase-polymerase chain reaction were conducted to study the expression of survivin and p53. The Fisher's exact test was employed to determine the association of survivin and p53 with clinicopathologic parameters of the subjects being studied. RESULTS: Positive staining for survivin was found in 72% OSCC and 44% oral premalignant lesions with no immunoreactions in the corresponding normal tissues. For p53, 59% OSCC, 38% premalignant lesions, and 14% normal tissues were positive. Importantly, about half of the p53-positive OSCC and premalignant tissues also showed survivin positivity (28% OSCC and 18% premalignant lesions). Further, it is observed that the number of survivin positive cells was significantly higher in the p53-positive group. Survivin is expressed in a varying proportion of cells, and in majority of patients it was localized in cytoplasm, whereas p53 is strictly restricted to the nucleus. The survivin expression levels in both primary OSCC and premalignant lesions were significantly higher than in normal oral tissues (OSCC, p < .0008; premalignant lesions, p < .04). No significant correlations between survivin and p53 expression with clinicopathologic parameters were found. CONCLUSIONS: Frequent overexpression of apoptosis regulators, survivin and p53, in OSCC as well as in oral premalignant lesions were found. Overexpression of these 2 markers in premalignant lesions suggest a role in early stages of oral carcinogenesis.