In Vitro Cell Death Mechanisms Induced by Dicoma anomala Root Extract in Combination with ZnPcS4 Mediated-Photodynamic Therapy in A549 Lung Cancer Cells

Alexander Chota; Blassan P George; Heidi Abrahamse

doi:10.3390/cells11203288

In Vitro Cell Death Mechanisms Induced by Dicoma anomala Root Extract in Combination with ZnPcS₄ Mediated-Photodynamic Therapy in A549 Lung Cancer Cells

Cells. 2022 Oct 19;11(20):3288. doi: 10.3390/cells11203288.

Authors

Alexander Chota¹, Blassan P George¹, Heidi Abrahamse¹

Affiliation

¹ Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, P.O. Box 1711, Doornfontein 2028, South Africa.

Abstract

Globally, lung cancer has remained the leading cause of morbidity and mortality in men and women. To enhance photodynamic therapeutic effects in vitro, the present study was designed to reduce dose-dependence in photodynamic therapy (PDT) and evaluate the anticancer effects of Dicoma anomala (D. anomala) root extracts (i.e., chloroform (Chl), ethyl acetate (EtOAc), and methanol (MeOH)) on A549 lung cancer cells. The most active extract of D. anomala (D.A) was used to establish the 50% inhibitory concentration (IC₅₀), which was further used to evaluate the anticancer efficacy of D.A in combination with ZnPcS₄-mediated PDT IC₅₀. The study further evaluated cell death mechanisms by cell viability/ cytotoxicity (LIVE/DEAD^TM assay), flow cytometry (Annexin V-fluorescein isothiocyanate (FITC)-propidium iodide (PI) staining), immunofluorescence (p38, p53, Bax, and caspase 3 expressions), and fluorometric multiplex assay (caspase 8 and 9) 24 h post-treatment with IC₅₀ concentrations of ZnPcS₄-mediated PDT and D.A MeOH root extract. Morphological changes were accompanied by a dose-dependent increase in cytotoxicity, decrease in viability, and proliferation in all experimental models. Apoptosis is the highly favored cell death mechanism observed in combination therapy groups. Apoptotic activities were supported by an increase in the number of dead cells in the LIVE/DEAD^TM assay, and the upregulation of p38, p53, Bax, caspase 3, 8, and 9 apoptotic proteins. In vitro experiments confirmed the cytotoxic and antiproliferative effects of D.A root extracts in monotherapy and in combination with ZnPcS₄-mediated PDT. Taken together, our findings demonstrated that D.A could be a promising therapeutic candidate worth exploring in different types of cancer.

Keywords: Dicoma anomala; apoptosis; lung cancer; photodynamic therapy; zinc phthalocyanine tetrasulfonate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Annexin A5
Caspase 3
Caspase 8
Cell Death
Chloroform
Female
Fluorescein-5-isothiocyanate
Humans
Lung Neoplasms* / drug therapy
Male
Methanol
Photochemotherapy*
Plant Extracts / pharmacology
Plant Extracts / therapeutic use
Propidium
Tumor Suppressor Protein p53
bcl-2-Associated X Protein

Substances

zinc(II) phthalocyanine trisulfonic acid
Caspase 3
Caspase 8
Annexin A5
Methanol
Chloroform
Propidium
Fluorescein-5-isothiocyanate
Tumor Suppressor Protein p53
bcl-2-Associated X Protein
Plant Extracts

Grants and funding

This research was funded by the South African Research Chairs initiative of the Department of science and technology and National Research Foundation of South Africa (Grant No. 98337), South African Medical Research Council (Grant No. SAMRC EIP007/2021), as well as grants received from the University Research Committee (URC), African Laser Centre (ALC), University of Johannesburg, and the Council for Scientific and Industrial Research (CSIR)-National Laser Centre (NLC).