A newly isolated strain of Halomonas sp. (HA1) exerts anticancer potential via induction of apoptosis and G2/M arrest in hepatocellular carcinoma (HepG2) cell line

Islam M El-Garawani,Omaima A Eissa,Sabha M El-Sabbagh,Nasser H Abbas,Doaa M Abo-Atya,Shaden A M Khalifa,Hany S Ahmed,Hesham R El-Seedi

doi:10.1038/s41598-020-70945-8

Abstract

Marine bacterial strains are of great interest for their ability to produce secondary metabolites with anticancer potentials. Isolation, identification, characterization and anticancer activities of isolated bacteria from El-Hamra Lake, Wadi El-Natrun (Egypt) were the objectives of this study. The isolated bacteria were identified as a moderately halophilic alkaliphilic strain. Ethyl acetate extraction was performed and identified by liquid chromatography-mass spectrophotometry (LC–MS–MS) and nuclear magnetic resonance analysis (NMR). Cytotoxicity of the extract was assessed on the HepG2 cell line and normal human peripheral lymphocytes (HPBL) in vitro. Halomonas sp. HA1 extract analyses revealed anticancer potential. Many compounds have been identified including cyclo-(Leu-Leu), cyclo-(Pro-Phe), C17-sphinganine, hexanedioic acid, bis (2-ethylhexyl) ester, surfactin C14 and C15. The extract exhibited an IC50 of 68 ± 1.8 μg/mL and caused marked morphological changes in treated HepG2 cells. For mechanistic anticancer evaluation, 20 and 40 µg/mL of bacterial extract were examined. The up-regulation of apoptosis-related genes' expression, P53, CASP-3, and BAX/BCL-2 at mRNA and protein levels proved the involvement of P53-dependant mitochondrial apoptotic pathway. The anti-proliferative properties were confirmed by significant G2/M cell cycle arrest and PCNA down-regulation in the treated cells. Low cytotoxicity was observed in HPBL compared to HepG2 cells. In conclusion, results suggest that the apoptotic and anti-proliferative effects of Halomonas sp. HA1 extract on HepG2 cells can provide it as a candidate for future pharmaceutical industries.

Highlights

Hepatocellular carcinoma (HCC) is the fifth type of cancer in patients with chronic liver disease and cirrhosis and the second cause of death in cancer p atients[1]
Several studies have indicated the advantages of marine flora and fauna extracts in combating cancer and a number of other d iseases[35,36,37]
Bacteria are the greatest producers of bioactive natural products and are of immense importance for drug d iscovery[20]

Summary

Introduction

Hepatocellular carcinoma (HCC) is the fifth type of cancer in patients with chronic liver disease and cirrhosis and the second cause of death in cancer p atients[1]. The characterization of bioactive compounds and evaluation of the possible anticancer potential of the bacterial extract against the HepG2 cell line were warranted. The bacterial extract has been examined for their anticancer activity against HepG2 cell line using MTT assay. Results of the inverted phase-contrast examination demonstrated the remarkable anticancer potentials as evidenced by cellular shrinkage and irregular cell shapes following bacterial extract treatments in a dose-dependent manner when compared with control groups (Fig. 4).

Results

Conclusion