Identification of native Bacillus thuringiensis strain from South India having specific cytocidal activity against cancer cells

Abstract

Aim: To identify the parasporin‐producing, indigenous Bacillus thuringiensis strains that specifically targets human cancer cells in Madurai, Tamil Nadu, South India. Methods and Results: Alkali‐solubilized inclusion proteins from the 82 nonclonal indigenous isolates of B. thuringiensis were analysed for their cytotoxicity against two human cancer cell lines, U‐937 (human histiocytic lymphoma) and HCT‐250 (adherent human colon cancer cells). Activated inclusion protein from one of the isolates, B. thuringiensis LDC‐391, was found to be highly cytotoxic to HCT‐250 and moderately toxic to U‐937, but nontoxic to normal lymphocytes. This strain did not show any insecticidal activity against the lepidopteran and dipteran larvae tested, as well as it was nonhaemolytic on human erythrocytes. The Western‐blotting analysis showed that the putative 180 kDa cytotoxic protein from the isolate B. thuringiensis LDC‐391 cross‐reacted with the reference antisera of 81‐kDa parasporin‐1. Conclusions: Our observations imply that B. thuringiensis LDC‐391 is different from the already reported parasporin producers, as it is showing variation in the target specificity. Significance and Impact of the Study: Characterizing these proteins can pave the way to alleviate problems associated with neoplastic transformation and cancer progression.

Bacillus spp.: Attractive Sources of Anti-cancer and Anti-proliferative Biomolecules

“…proteins are yet to be classi ed (Poornima et al, 2010;Gonzalez et al, 2011;Ammons et al, 2016). Among these six classes of parasporin, only PS1 kills cancer cells by activating apoptotic signaling pathway causing from attenuation of cellular protein and DNA synthesis, and by increasing in ux of calcium ions (Katayama et al,2007).…”

Phenotypic and genotypic characterization of B.t.LDC-391 strain that produce cytocidal proteins against human cancer cells

“…These strains are usually non haemolytic and non-motile with other phenotypic characters similar to that of insecticidal B.thuringiensis strains. B.t .LDC-391, investigated in this study is one such soil isolates from southern part of India, showing cytotoxicity against human colon cancer cell line, HCT-116 [6]. Albeit this strain possesses parasporal inclusions which is a common feature of B.thuringiensis species, the distinctness of this strain at morphological and molecular level to other related species needs to be investigated.…”

Novel Toxicity of <i>Bacillus thuringiensis</i> Strains against the Melon Fruit Fly, <i>Bactrocera cucurbitae</i> (Diptera: Tephritidae)

“…The logarithmic value of the concentration of spores was the basis for LC 50 and LC 99 determination instead of proteins because actual amount of the active proteins should be confirmed for the strains expressing more than one protein. From this analysis, the LC 50 value of Bt JSc1 and the LC 99 value of Bt SSc2 were found to be highly comparable to those of Btk HD-73 Table 1 . 16S rRNA gene sequence analysis has been used as a molecular identification tool for Bt and the claims of its ability to discriminate Bt in different H-serotypes also was reported Joung and Cote, 2002;Soufiane and Cote, 2009;Poornima et al, 2010 . In the present study, 16S rRNA gene analysis was performed with 19 degraded product of Cry1 protein Armengol et al, 2006 .…”