Shiga-Like Toxin Produced by Local Isolates of Escherichia coli O157:H7 Induces Apoptosis of the T47 Breast Cancer Cell Line

Komang Januartha Putra Pinatih; I Wayan Suardana; Dyah Ayu Widiasih; Hamong Suharsono

doi:10.1177/11782234211010120

Shiga-Like Toxin Produced by Local Isolates of Escherichia coli O157:H7 Induces Apoptosis of the T47 Breast Cancer Cell Line

Breast Cancer (Auckl). 2021 Apr 28:15:11782234211010120. doi: 10.1177/11782234211010120. eCollection 2021.

Authors

Komang Januartha Putra Pinatih¹, I Wayan Suardana², Dyah Ayu Widiasih³, Hamong Suharsono⁴

Affiliations

¹ Department of Clinical Microbiology, Faculty of Medicine, Udayana University, Denpasar, Indonesia.
² Laboratory of Veterinary Public Health, Department of Preventive Veterinary Medicine, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia.
³ Department of Veterinary Public Health, Faculty of Veterinary Medicine, Gadjah Mada University, Yogyakarta, Indonesia.
⁴ Laboratory of Veterinary Biochemistry, Department of Basic Veterinary Medicine, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia.

Abstract

Purpose: It has been suggested that Shiga-like toxins produced by Escherichia coli O157:H7 could be used as novel therapeutic agents against malignant tumors. In addition, the antitumor potency of local isolates from Indonesia, which are known to be less toxic than the control isolate ATCC 43894, has not yet been tested. The study aimed to analyze local strains of E. coli O157:H7 as a proapoptosis agent on the T47 breast cancer cell line.

Methods: As many as 30 culture cells of T47D breast cancer cell line were subjected to purified extracts of Shiga-like toxin originating from 5 local isolates of E. coli O157:H7: KL-48(2), SM-25(1), SM-7(1), DS-21(4), and 1 isolate ATCC 43894 which was used as a control. Toxin production of each isolate was detected using a sandwich enzyme-linked immunosorbent assay, and the treatment of cell lines was observed for 24 hours, with 2 replications; 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide tests and acridine orange/ethidium bromide double staining assays were used for detection and analyses of apoptosis.

Results: The study showed 2 local strains of E. coli O157:H7 (codes KL-48(2) and SM-25(1)) had toxins positive at titer 5 and 10 μg/100 μL. These titers were lower than the control isolate ATCC 43894, but they had a necrosis effect higher (P < .05), ie, 80.3%, than control isolate, ie, 63.3%. Other local strain SM-25(1) also had a good necrosis effect. It has a nondifferent necrosis effect (P > .05) with the control isolate ATCC 43894, ie, 13.0% from 13.3%.

Conclusion: This study concludes that the Shiga toxin produced by E. coli O157:H7 local isolate (Indonesia) has potential as a proapoptotic and/or necrotic agent for treating T47 breast cancer cell lines, as effectively as ATCC 43894 control isolates.

Keywords: Breast cancer; E. coli O157:H7; Shiga-like toxin; T47 cell line; proapoptosis.