Semaphorin 3A upregulates FOXO 3a-dependent MelCAM expression leading to attenuation of breast tumor growth and angiogenesis.

Semaphorin 3A (Sema 3A), a member of semaphorin family, serves as a guidance clue during embryonic development and is known as a candidate tumor suppressor that attenuates breast tumor progression by binding with its co-receptor, neuropilin-1 (NRP-1). However, the underlying mechanism by which Sema 3A suppresses breast tumor growth is still unexplored. In this study, we report that Sema 3A regulates phosphorylation and nuclear translocation of phosphatase and tensin homolog (PTEN) and FOXO 3a. Moreover, Sema 3A controls NRP-1-mediated PTEN-dependent FOXO 3a activation. Overexpression of PTEN and FOXO 3a enhances Sema 3A-induced attenuation of breast cancer cell migration. Chromatin immunoprecipitation and electrophoretic mobility shift assay data revealed that FOXO 3a regulates MelCAM at the transcriptional level. Furthermore, Sema 3A induces NRP-1-mediated MelCAM expression through PTEN and FOXO 3a. The data also showed that vascular endothelial growth factor-induced angiogenesis is inhibited by Sema 3A. Loss of or gain in function study revealed that Sema 3A modulates phosphorylation of PTEN and FOXO 3a and expression of MelCAM, leading to suppression of tumor growth and angiogenesis using in vivo mice model. Clinical specimen analysis revealed that reduced expression of Sema 3A and p-PTEN are correlated with enhanced breast cancer progression, further strengthening our in vitro and in vivo findings. Correlation of relapse-free survival of breast cancer patients (n=2878) with expression levels of Sema 3A, NRP-1, FOXO 3a and MelCAM were studied by Kaplan-Meier analysis. Statistical analysis revealed a close association between reduced expression of Sema 3A and MelCAM with that of poor patient's survival. Our study demonstrated a novel mechanism of regulation of tumor suppression by Sema 3A in coordination with a chain of tumor-suppressor genes, which in turn inhibits breast cancer cell migration, tumor growth and angiogenesis.

Hypoxia-driven osteopontin contributes to breast tumor growth through modulation of HIF1α-mediated VEGF-dependent angiogenesis.

Hypoxia is a salient feature of most solid tumors, and hypoxic adaptation of cancer cells has crucial implications in propagation of malignant clonal cell population. Osteopontin (OPN) has been identified as a hypoxia-responsive gene, but the mechanistic and regulatory role of OPN under hypoxia is less characterized. The present study identifies the existence of a positive inter-regulatory loop between hypoxia and OPN. We have shown that hypoxia induces OPN expression in breast cancer cells; however, the expression was found to be HIF1α independent. OPN enabled transcriptional upregulation of HIF1α expression both under normoxia and hypoxia, whereas stability of HIF1α protein in breast cancer cells remained unaffected. Moreover, we have shown that OPN induces integrin-linked kinase (ILK)/Akt-mediated nuclear factor (NF)-κB p65 activation leading to HIF1α-dependent vascular endothelial growth factor (VEGF) expression and angiogenesis in response to hypoxia. These in vitro data are biologically important as OPN expressing cells induce greater tumor growth and angiogenesis through enhanced expressions of proangiogenic molecules as compared with control. Immunohistochemical analysis of human breast cancer specimens revealed significant correlation between OPN and HIF1α but not HIF2α. Elevated expression of HIF1α and OPN was observed in pre-neoplastic and early stage infiltrating ductal carcinoma implicating the role of these proteins in neoplastic progression of breast cancer. Together, our results substantiate the prime role of OPN in cellular adaptation through ILK and NF-κB-mediated HIF1α-dependent VEGF expression in response to hypoxia that ultimately controls breast cancer progression and angiogenesis. Our study reinforces the fact that targeting OPN and its regulated signaling network hold important therapeutic implications.

Osteopontin signaling upregulates cyclooxygenase-2 expression in tumor-associated macrophages leading to enhanced angiogenesis and melanoma growth via α9ß1 integrin.

Tumor-associated macrophages (TAMs) have multifaceted roles in tumor development, particularly linked with tumor angiogenesis and invasion, but the molecular mechanism underlying this association remains unclear. In this study, we report that lack of osteopontin (OPN) suppresses melanoma growth in opn(-/-) mice and macrophages are the crucial component responsible for OPN-regulated melanoma growth. In tumor microenvironment, OPN activates macrophages and influences angiogenesis by enhancing cyclooxygenase-2 (COX-2)-dependent prostaglandin E2 (PGE2) production in an autocrine manner. Furthermore, we identify α9ß1 integrin as a functional receptor for OPN that mediates its effect and activates ERK and p38 signaling, which ultimately leads to COX-2 expression in macrophages. The major role played by OPN and PGE2 in angiogenesis are further amplified by upregulation of MMP-9. OPN-activated macrophages promote the migration of endothelial and cancer cells via PGE2. These findings provide evidence that TAMs serve as source of key components such as OPN and COX-2-derived PGE2 and MMP-9 in melanoma microenvironment. Clinical specimens analyses revealed that increased infiltration of OPN-positive TAMs correlate with melanoma growth and angiogenesis. These data provide compelling evidence that OPN and COX-2 expressing macrophages are obligatory factors in melanoma growth. We conclude that OPN signaling is involved in macrophage recruitment into tumor, and our results emphasize the potential role of macrophage in modulation of tumor microenvironment via secretion of OPN, PGE2 and MMP-9, which trigger angiogenesis and melanoma growth. Thus, blockade of OPN and its regulated signaling network provides unique strategy to eradicate melanoma by manipulating TAMs.

Need and strategy for sentinel surveillance for drug resistance in leprosy in India.

In the fight against leprosy drug resistance poses a serious impediment at a stage when there is dramatic decline in prevalence due to intensive and concerted chemotherapy intervention. Drug resistance in leprosy has been reported since 1964 for dapsone, 1976 for rifampicin and 1996 for ofloxacin. Recent reports and publications have indicated few instances of rifampicin resistance in several endemic areas. In light of reporting drug resistance in leprosy, the National Leprosy Eradication Programme (NLEP) in India has started collecting information on relapse cases from peripheral institutions. The data show quite significant number of relapse cases (328 in year 2008-09) reported from few endemic states. Comprehensive data on the magnitude of drug resistance are crucial to evaluate the efficacy of MDT and to maintain the effectiveness of the current leprosy control strategy. It has become a necessity to develop a surveillance system to keep a close vigil on drug resistance. PCR based assays have convincingly demonstrated that detection of rifampicin resistance by this method is a feasible and practical alternative to the mouse foot pad (MFP) assay and has practical application in India. Surveillance of drug resistance in leprosy can be carried out based on a sentinel surveillance model. Certain district hospitals and tertiary institutions can be identified as sentinel sites in endemic states where tissue samples can be collected and transported to the identified reference laboratories. Based on the suspected and confirmed relapsed cases reported, 12 states have been identified for inclusion under the surveillance of drug resistance in leprosy. These are Andhra Pradesh, Bihar, Chhattisgarh, Karnataka, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Tamilnadu, Uttar Pradesh, West Bengal and Delhi. Four reference laboratories have already been identified, one each in the states of Uttar Pradesh, Andhra Pradesh, Tamilnadu and Delhi. Tissue samples from sentinel sites would be sent to designated laboratories for conducting the DNA sequencing tests to confirm rifampicin resistance.

Need and strategy for sentinel surveillance for drug resistance in leprosy in India

In the fight against leprosy drug resistance poses a serious impediment at a stage when there is dramatic decline in prevalence due to intensive and concerted chemotherapy intervention. Drug resistance in leprosy has been reported since 1964 for dapsone, 1976 for rifampicin and 1996 for ofloxacin. Recent reports and publications have indicated few instances of rifampicin resistance in several endemic areas. In light of reporting drug resistance in leprosy, the National Leprosy Eradication Programme (NLEP) in India has started collecting information on relapse cases from peripheral institutions. The data show quite significant number of relapse cases (328 in year 2008-09) reported from few endemic states. Comprehensive data on the magnitude of drug resistance are crucial to evaluate the efficacy of MDT and to maintain the effectiveness of the current leprosy control strategy. It has become a necessity to develop a surveillance system to keep a close vigil on drug resistance. PCR based assays have convincingly demonstrated that detection of rifampicin resistance by this method is a feasible and practical alternative to the mouse foot pad (MFP) assay and has practical application in India. Surveillance of drug resistance in leprosy can be carried out based on a sentinel surveillance model. Certain district hospitals and tertiary institutions can be identified as sentinel sites in endemic states where tissue samples can be collected and transported to the identified reference laboratories. Based on the suspected and confirmed relapsed cases reported, 12 states have been identified for inclusion under the surveillance of drug resistance in leprosy. These are Andhra Pradesh, Bihar, Chhattisgarh, Karnataka, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Tamilnadu, Uttar Pradesh, West Bengal and Delhi. Four reference laboratories have already been identified, one each in the states of Uttar Pradesh, Andhra Pradesh, Tamilnadu and Delhi. Tissue samples from sentinel sites would be sent to designated laboratories for conducting the DNA sequencing tests to confirm rifampicin resistance.

Epidemiological trends of leprosy elimination in CLTRI rural field operation area, Tamil Nadu, India.

The analysis of computerized data of patients in our Rural Field Operation Area (Kunrathur Taluk, Kancheepuram District, Tamil Nadu) from the start of MDT in 1986 has shown a decrease of leprosy prevalence from 275/10000 in 1986 to 0.7/10000 in 2005. Leprosy has been eliminated as a public health problem after 19 years of MDT implementation. Although the control programme was started in 1962, MDT implementation began only in 1986. The new case-detection rate has declined significantly from 27.3 in 1987 to 2.4/10000 in 2005 (y = -1.6x + 2325.1, p = < 0.05). The age-specific cumulative detection rates calculated showed highest case-detection at 10-14 years for total, 10-14 years for PB, 50-54 for MB, and 10-14 for both males and females. MB percentage was more among new cases in the last three years as compared to the initial three years, and this difference was found to be statistically significant, but there was no significant difference between the first three and the last three-year periods in child, male and disability rates (grade +/-2) among new cases. Thus, the declining trend in NCDR has not reflected any change in sex and age-groups of new cases. This analysis strengthens the hypothesis of sub-clinical cases possibly transmitting the disease and MB cases accruing after long incubation period.

A study on trend of relapse in leprosy and factors influencing relapse.

A retrospective analysis of data pertaining to the rural field operation area of the Central Leprosy Teaching and Research Institute, Chengalpattu, Tamil Nadu, was carried out to determine the magnitude of relapse after MDT and its significance with other variables. The study included 3248 leprosy patients who have successfully completed treatment during 1987-2003, of whom 2892 were PB and 356 MB cases. A total of 58 cases of relapse was reported which gives a crude cumulative relapse rate of 1.78% for the 16-year period of follow-up and the rates for PB and MB were 1.9% and 0.84% respectively. With respect to PB cases, 68% of relapses were reported in the first 3 years of RFT. The person-year relapse rate was highly significant with regard to the number of skin lesions (p<0.0002) and nerve involvement (p<0.0002). The person-year relapse rate did not differ significantly between PB and MB leprosy, male and female, and child and adult cases. RFT year cohort relapse rate reveals that the introduction of MB-MDT regimen for PB leprosy had resulted in the reduction of relapses among PB cases after 1998. The relapse rate with reference to the time gap after RFT reveals that relapse declines with passage of time after RFT. The risk of relapse was very low in both PB and MB leprosy which fact emphasizes that proper counselling about signs and symptoms of relapse during RFT is adequate to combat the problem. A majority of relapses occurred in the first three years after RFT. The number of skin lesions and involvement of nerves were the main risk factors for relapse.

Particle size distribution and respiratory deposition estimates of beryllium aerosols in an extraction and processing plant.

The mass size distribution of beryllium aerosols generated in the various operational areas of a typical extraction and processing plant was studied using an eight-stage impactor sampler. The total concentration of beryllium in the plant was found to be well below the threshold limit value. The mean value of mass median aerodynamic diameter of beryllium particles observed for various operations ranged from 5.0-9.5 microm. The alveolar deposition for various operational areas was estimated to be 3-5% for nasal breathing and 9-13% for oral breathing based on the International Commission on Radiological Protection (ICRP) human respiratory tract model. Deposition during oral breathing was higher than during nasal breathing by approximately a factor of two to three. This study on exposure characterization was useful for reducing the respirable fraction of beryllium aerosol by optimizing the capture velocity and improving the quality of other control measures.

Leprosy situation in endemic states of India and prospects of elimination of the disease.

In India there is a dramatic fall in the prevalence rate (PR) of leprosy, but the new case-detection rate (NCDR) has not been reduced concomitantly. It is the operational efficiency of the National Leprosy Eradication Programme (NLEP) that has led to a significant reduction in the NCDR in Andhra Pradesh and Tamil Nadu. The ratio of PR to NCDR has been declining in these two states and it reveals that elimination could be reached even with the high NCDR level of 3 to 4 per 10000 population, particularly if single skin lesion (SSL) cases are discharged through single dose treatment of rifampicin, ofloxacin and minocycline (ROM). On the other hand, the significant number of cases detected in Bihar and Orissa during modified leprosy elimination campaigns (MLECs) reveals that there are lacunae in operational activities in new case-detection resulting in a large number of undetected cases in the community. Only one-third of the cases are reporting voluntarily. Awareness of leprosy is not adequate to motivate the patients to report voluntarily and complete their treatment, thus underscoring the need for relying on active case-detection so that transmission can be broken and elimination of leprosy achieved. In addition, the influence of socio-economic factors on continued occurrence of leprosy cannot be ruled out. The establishment of a sentinel surveillance system along with a computerized simplified information system to gain in-depth knowledge on the functioning of the NLEP will ensure operational efficiency. In view of this situation, the NLEP should adopt a more realistic approach towards reaching the elimination goal.

Beryllium concentrations in ambient air and its source identification. A case study.

Beryllium concentrations in atmospheric particulate and soil samples in and around a Beryllium Processing Facility (BPF) have been measured. The mean air concentration level of beryllium in and around the fence line of the BPF is 0.48 +/- 0.43 ng m(-3) (n = 397) and is mostly influenced by diurnal and seasonal changes. The observed air concentration levels were well below the prescribed ambient air quality (AAQ) standard of 10 ng m(-3). The soil concentration levels of beryllium in the study area were found to be in the range of 1.42-2.75 microg g(-1). The mass median aerodynamic diameter (MMAD) of beryllium aerosols in ambient air was found to be 6.9 microm. Source identification using the Enrichment Factor (EF) approach indicates soil as the predominant contributory source for air concentrations at the site.