Selective cytotoxic activity against leukemic cell lines from mosquitocidal Bacillus thuringiensis parasporal...

Area of Science:

• Microbiology
• Biochemistry
• Cancer Research

Background:

• Parasporin discovery spurred interest in Bacillus thuringiensis (Bt) for anti-cancer applications.
• Mosquitocidal Bt isolates were screened for cytotoxic effects on cancer cell lines.

Purpose of the Study:

• To evaluate the anti-leukemic potential of parasporal inclusions from Malaysian mosquitocidal Bt isolates against the CEM-SS cell line.
• To determine the specificity and mechanism of action of cytotoxic Bt parasporal inclusions.

Main Methods:

• Screening of 12 mosquitocidal Bt isolates for cytotoxicity against CEM-SS and HeLa cell lines.
• Analysis of non-hemolytic Bt isolate (Bt 18) for specificity against normal T lymphocytes.
• SDS-PAGE and N-terminal sequencing of Bt 18 parasporal inclusions.
• Apoptosis assays to determine the mode of cell death.

Main Results:

• Most Bt isolates exhibited low to moderate cytotoxicity against CEM-SS and HeLa cells.
• Bt 18 parasporal inclusions showed specific cytotoxicity towards CEM-SS cells, sparing normal T lymphocytes.
• Bt 18 induced apoptosis in leukemic cells.
• Bt 18 parasporal inclusions showed similarities to Cry proteins from B. thuringiensis subsp jegathesan and B. thuringiensis subsp israelensis.

Conclusions:

• Bt 18 parasporal inclusions possess selective anti-leukemic activity and therapeutic potential.
• Bt 18's non-hemolytic yet discriminately cytotoxic nature suggests properties similar to Parasporin.
• Further research into Bt 18 for cancer therapy is warranted.