Abstract The present study tested the effects of a newly identified indolin-3-one compound (compound 1, produced by Pseudomonas aeruginosa, on HepG2 cells. The MTT assays demonstrated decreased metabolic activities in HepG2 cells treated with compound 1, with dose- and time-dependent intensifying effect, starting at a concentration of 40u2009µM. The IC50 after 24, 48, 72, and 96u2009h treatments were 41.35, 52.7, 92.79 and 66.65u2009μM of compound 1, respectively. Below 80u2009µM, no significative damage on erythrocytes membranes was observed by the hemolytic assays. The RT-qPCR revealed that the compound modulated key genes involved in carcinogenesis process, indicating possible indolin-3-one mechanisms of action. The data showed that gene expression alterations promoted by compound 1,... in concentrations up to 60u2009μM after 48u2009h, led to a decrease in cellular progression and there was no direct cellular damage. In addition, non-cytotoxic concentrations of compound 1 halved the concentration of the chemotherapeutic doxorubicin, maintaining similar therapeutic effect against HepG2 cells. The novelty of the molecule and the biological activities observed in the present study emphasize the potential of the compound 1 in cancer therapy research.