Impact of Rapid Urbanization on the Rates of Infection by Vibrio cholerae O1 and Enterotoxigenic Escherichia coli in Dhaka, Bangladesh

Bangladesh is a country where acute dehydrating diarrhea or cholera is common and is seen at least two times every year and additionally in natural disasters. In addition cholera cases have increased in the country, especially in urban settings such as in the capital city, Dhaka, where the number of hospitalized patients with more severe disease has tremendously increased. In the present observation, we have concentrated on determining the occurrence of diarrhoea caused by the two most common bacterial agents V. cholerae O1 and enterotoxigenic Escherichia coli (ETEC) in a densely populated, disease prone area Mirpur in Dhaka for two years from March 2008 to February 2010. Stool or rectal specimens from diarrheal patients coming to the ICDDR,B hospital from Mirpur were tested for the two bacterial pathogens. We found that V. cholerae O1 was the major bacterial pathogen and a cause of severe cholera disease in 23% of patients (2,647 of a total of 11,395 patients) from Mirpur. We surmise that cholera vaccines, as well as other public health tools that can target such high risk groups in the country, will be able to reduce the disease morbidity and the transmission of pathogens to improve the quality of life in urban settings

Inhibition of Breast Tumour Growth with Intravenously Administered PRKCA siRNA- and PTEN Tumour Suppressor Gene-Loaded Carbonate Apatite Nanoparticles

Gene therapy aims to silence an oncogene through RNA interference, or replace an abnormal tumour suppressor via gene augmentation. In this study, we intended RNA interference for PRKCA oncogene and gene augmentation for PTEN tumour suppressor with a view to reduce tumour growth in a mouse model of breast cancer. Inorganic carbonate apatite nanoparticles (CA NPs) were utilized to deliver the synthetic siRNA and the purified gene-carrying plasmid DNA both in vitro and in vivo. Effects of PRKCA siRNA- and PTEN plasmid-loaded NPs on viability of MCF-7, MDA-MB-231 and 4T1 breast cancer cells were assessed by MTT assay. The cell viability data in MCF-7 cell line demonstrated that combined delivery of PRKCA specific siRNA and PTEN plasmid with CA NPs had an additive effect to significantly decrease cellular growth compared to individual treatments. In addition, we observed a similar pattern of cumulative influence for combined treatment in triple negative MDA-MB-231 breast cancer cell line. Upon treatment with PRKCA siRNA+PTEN plasmid-loaded NPs, a remarkable decrease in the phosphorylated form of AKT protein of PI3K/AKT pathway was observed in Western blot, indicative of diminished proliferative signal. Moreover, in vivo study in MCF-7 xenograft breast cancer mouse model demonstrated that the rate of growth and final tumour volume were reduced significantly in the mouse group that received intravenous treatment of PRKCA siRNA+NPs, and PTEN plasmid+NPs. Our findings demonstrated that PRKCA siRNA and PTEN plasmid loaded into CA NPs attenuated breast tumour growth, suggesting their therapeutic potential in the treatment of breast cancer

Retarding breast tumor growth with nanoparticle-facilitated intravenous delivery of BRCA1 and BRCA2 tumor suppressor genes

Abstract Gene augmentation therapy entails replacement of the abnormal tumor suppressor genes in cancer cells. In this study, we performed gene augmentation for BRCA1/2 tumor suppressors in order to retard tumor development in breast cancer mouse model. We formulated inorganic carbonate apatite (CA) nanoparticles (NPs) to carry and deliver the purified BRCA1/2 gene- bearing plasmid DNA both in vitro and in vivo. The outcome of BRCA1/2 plasmid-loaded NPs delivery on cellular viability of three breast cancer cell lines such as MCF-7, MDA-MB-231 and 4T1 were evaluated by MTT assay. The result in MCF-7 cell line exhibited that transfection of BRCA 1/2 plasmids with CA NPs significantly reduced cancer cell growth in comparison to control group. Moreover, we noticed a likely pattern of cellular cytotoxicity in 4T1 murine cancer cell line. Following transfection with BRCA1 plasmid-loaded NPs, and Western blot analysis, a notable reduction in the phospho-MAPK protein of MAPK signaling pathway was detected, revealing reduced growth signal. Furthermore, in vivo study in 4T1 induced breast cancer mouse model showed that the tumor growth rate and final volume were decreased significantly in the mouse group treated intravenously with BRCA1 + NPs and BRCA2 + NPs formulations. Our results established that BRCA1/2 plasmids incorporated into CA NPs mitigated breast tumor growth, signifying their application in the therapy for breast cancer

Inhibition of breast tumour growth with intravenously administered PRKCA siRNA-and PTEN tumour suppressor gene-loaded carbonate apatite nanoparticles

Gene therapy aims to silence an oncogene through RNA interference, or replace an abnormal tumour suppressor via gene augmentation. In this study, we intended RNA interference for PRKCA oncogene and gene augmentation for PTEN tumour suppressor with a view to reduce tumour growth in a mouse model of breast cancer. Inorganic carbonate apatite nanoparticles (CA NPs) were utilized to deliver the synthetic siRNA and the purified gene-carrying plasmid DNA both in vitro and in vivo. Effects of PRKCA siRNA- and PTEN plasmid-loaded NPs on viability of MCF-7, MDA-MB-231 and 4T1 breast cancer cells were assessed by MTT assay. The cell viability data in MCF-7 cell line demonstrated that combined delivery of PRKCA specific siRNA and PTEN plasmid with CA NPs had an additive effect to significantly decrease cellular growth compared to individual treatments. In addition, we observed a similar pattern of cumulative influence for combined treatment in triple negative MDA-MB-231 breast cancer cell line. Upon treatment with PRKCA siRNA+PTEN plasmid-loaded NPs, a remarkable decrease in the phosphorylated form of AKT protein of PI3K/AKT pathway was observed in Western blot, indicative of diminished proliferative signal. Moreover, in vivo study in MCF-7 xenograft breast cancer mouse model demonstrated that the rate of growth and final tumour volume were reduced significantly in the mouse group that received intravenous treatment of PRKCA siRNA+NPs, and PTEN plasmid+NPs. Our findings demonstrated that PRKCA siRNA and PTEN plasmid loaded into CA NPs attenuated breast tumour growth, suggesting their therapeutic potential in the treatment of breast cancer

Carbonate apatite:effect of serum and impact on the cellular proteome

Carbonate apatite (CA) is a synthetic derivative of hydroxyapatite, which we have been exploring as a drug delivery nanocarrier in the context of cancer in vitro and in vivo. This nanocarrier showed great potential delivering anti-cancer drugs, plasmids containing tumour suppressor genes and siRNAs against oncogenes in pre-clinical models. We compared here two formulations of CA—the low-Ca2+ CA (made with 4 mM Ca2+) used for in vitro studies in cell lines and the high-Ca2+ CA (made with 40 mM Ca2+) used in mouse models—in terms of protein corona formed with different concentrations of serum in vivo and in vitro. The 10-fold more Ca2+ in high-Ca2+ CA helped produce enough particles in an injectable volume for in vivo delivery of therapeutics. Both formulations made particles of similar size, but their composition differed slightly in terms of Na and Mg content. In serum-containing media, the size of the particles was dependent on the serum concentration. The protein corona around both formulations was almost similar and included albumin, fetuin, haemoglobin, and immunoglobulins. CA was not cytotoxic, and instead an increased expression of ribosomal machinery and glycolytic and cytoskeletal proteins was observed, which promoted translation, growth, and proliferation in cancer cells.</p

Shift in Phenotypic Characteristics of Enterotoxigenic <i>Escherichia coli</i> (ETEC) Isolated from Diarrheal Patients in Bangladesh

<div><p>Background</p><p>Enterotoxigenic <i>Escherichia coli</i> (ETEC) is one of the most common causes of bacterial diarrhea. Over the last decade, from 1996 to 2012, changes in the virulence antigen properties of ETEC such as heat labile (LT) and heat stable (ST) toxins, colonization factors (CFs), and ‘O’-serogroups have been observed. The aim of this prospective study was to compare changes in antigenic profiles of ETEC strains isolated from a 2% surveillance system at the icddr,b hospital in Dhaka, Bangladesh between 2007–2012 and an earlier time period of 1996–1998 conducted at the same surveillance site.</p><p>Methodology</p><p>In the surveillance system every 50^th patient attending the hospital was screened for major enteric pathogens including ETEC, <i>Vibrio cholerae</i>, <i>Shigella</i> spp. and <i>Salmonella</i> spp. from January 2007 to December 2012.</p><p>Principal Findings</p><p>Of the 15,152 diarrheal specimens tested between 2007–2012, the overall rate of ETEC isolation was 11%; of these, 43% were LT/ST, 27% LT and 30% ST positive. Isolation rate of ST-ETEC (p<0.009) and LT/ST ETEC (p<0.011) during 2007–2012 period differed significantly compared to those seen between 1996–1998. In comparison to the 1996–1998 period, difference in CF profile of ETEC isolates during 2007–2012 was observed particularly for strains expressing CS7 (12.4%), CS14 (9.5%) and CS17 (10.0%). The predominant CF types were CS5+CS6, CFA/I, CS7, CS17, CS1+CS3, CS6 and CS14. The most common serogroups among the CF positive ETEC isolates were O115, O114, O6, O25 and O8. A strong association was found between CFs and ‘O’ serogroups i.e. between CS5+CS6 and (O115 and O126); CS7 and (O114), CFA/I and (O78 and O126), CS17 and (O8 and O167) and CS1/CS2+CS3 and (O6).</p><p>Conclusion</p><p>The analyses show a shift in prevalence of antigenic types of ETEC over the study period; the information is important in designing effective ETEC vaccines with broad protective coverage.</p></div

Relative distribution of colonization factors (CFs) in ETEC isolates from diarrhea cases in Bangladesh according to year of isolation and association of specific CFs with toxin profile.

<p>Relative distribution of colonization factors (CFs) in ETEC isolates from diarrhea cases in Bangladesh according to year of isolation and association of specific CFs with toxin profile.</p

Relationship between toxin profile and dehydration status of ETEC diarrheal patients during 2007–2012.

<p>p value for chi-squared test: 0.046 (2010–2012); indicates LT vs LT/ST ETEC for severe cases.</p>a<p>Degree of dehydration based on World Health Organization guideline.</p