Physalin F from Physalis minima L. triggers apoptosis-based cytotoxic mechanism in T-47D cells through the activation caspase-3- and c-myc-dependent pathways.
BACKGROUND
Physalin F (a secosteroid derivative), is well recognized as a potent anticancer compound from Physalis minima L., a plant that is traditionally used to treat cancer. However, the exact molecular anticancer mechanism remains to be elucidated.


OBJECTIVE
We have recently reported the apoptosis-based cytotoxic effect of the chloroform extract of this plant. Here, we investigated the cytotoxicity and possible cell death mechanism elicited by the active constituent, physalin F on human breast T-47D carcinoma.


METHODS
Cytotoxic-guided fractionation of the chloroform extract of Physalis minima has led to the isolation of physalin F. The cytotoxicity activity was assayed using MTS assay. The effect of the compound to induce apoptosis was determined by biochemical and morphological observations through DeadEnd Colorimetric and annexin V assays, respectively, and RT-PCR analysis of mRNA expression of the apoptotic-associated genes.


RESULTS
Cytotoxicity screening of physalin F displayed a remarkable dose-dependent inhibitory effect on T-47D cells with lower EC50 value (3.60 μg/ml) than the crude extract. mRNA expression analysis revealed the co-regulation of c-myc- and caspase-3-apoptotic genes in the treated cells with the peak expression at 9 and 12h of treatment, respectively. This apoptotic mechanism is reconfirmed by DNA fragmentation and phosphatidylserine externalization.


CONCLUSIONS
These findings indicate that physalin F may potentially act as a chemopreventive and/or chemotherapeutic agent by triggering apoptosis mechanism via the activation of caspase-3 and c-myc pathways in T-47D cells.
School of Biological Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
Kheng Leong
KL
Ooi
Tengku Sifzizul Tengku
TS
Muhammad
Shaida Fariza
SF
Sulaiman
D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D032321:Physalis; D010936:Plant Extracts / Q000737:chemistry; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012632:Secosteroids / Q000302:isolation & purification / Q000494:pharmacology*
D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012632:Secosteroids; C075425:physalin F; D053148:Caspase 3
Apoptosis; Caspase-3; Cytotoxicity; Physalin F; c-myc