Acetylshikonin exerts anti-tumor effects on non-small cell lung cancer through dual inhibition of STAT3 and EGFR.

BACKGROUND: Lung cancer is one of the most common types of malignant tumor. It has one of the highest morbidity and mortality rates worldwide, and approximately 85% of cases are non-small cell lung cancer (NSCLC). Clinically, several EGFR inhibitors have been used to treat NSCLC, but resistance can develop. Studies have shown that cross talk between signal transducer and activator of transcription 3 (STAT3) and epidermal growth factor receptor (EGFR) can mediate drug resistance. Acetylshikonin has obvious antitumor effects, but the mechanism of action is still unclear. PURPOSE: To analyze the antitumor activity of acetylshikonin in lung cancer and clarify its molecular mechanism. METHODS: Methyl thiazolyl tetrazolium (MTT), colony formation and 5-ethynyl-2'-deoxyuridine (EDU) assays were performed to examine the effects of acetylshikonin in inhibiting the proliferation of NSCLC cells (PC-9, H1975 and A549). Scratch wound and transwell assays were used to evaluate the migration and invasion of NSCLC cells. Flow cytometry was employed to determine whether acetylshikonin could induce apoptosis. Proteome sequencing was used to identify the targets of acetylshikonin. Immunofluorescence staining and western blotting were utilized to verify the inhibition of STAT3 and EGFR phosphorylation. A xenotransplantation model was established to evaluate the efficacy of acetylshikonin in nude mice. RESULTS: Our data demonstrated that acetylshikonin significantly decreased the survival rate of human NSCLC cells, increased the apoptotic rate and inhibited cell migration dose-dependently. Immunofluorescence staining and western blotting analyses revealed that acetylshikonin inhibited EGFR and STAT3 pathways. Acetylshikonin also inhibited tumor growth in a xenograft model better than inhibitors of EGFR and STAT3. CONCLUSION: Acetylshikonin has anti-cancer effects on NSCLC cells by inhibiting EGFR and STAT3, indicating that acetylshikonin may be a new antitumor drug to treat NSCLC.

Intravitreal injection of docosahexaenoic acid attenuated photoreceptor cell injury in a NaIO3-induced age-related macular degeneration rat model.

In most studies, the major supplement docosahexaenoic acid (DHA) is administered orally or intraperitoneally. In this study, we proposed to assess the safety and efficacy of the intravitreal injection of DHA in an age-related macular degeneration (AMD) rat model. Different concentrations of DHA were injected into the vitreous body. Histopathology and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) analysis showed that there was no difference in thickness, observable structure, or apoptosis among the untreated, normal saline, and DHA groups (0.2, 1.0, 5.0 and 10µg). However, GFAP expression was increased in the 10µg group. To investigate whether intravitreal injection of DHA could protect photoreceptors, we developed a NaIO3-induced retinal damage model in adult rats. Decreases in deformation and thickness were observed in the outer nuclear layer (ONL) after NaIO3 administration but were improved with DHA injection. The NaIO3 group showed a substantial reduction in the number of nuclei in ONL, whereas the DHA group showed an increase. Additionally, significant increases in SOD activity and Nrf2 expression were observed after DHA injection; GFAP and NF-κB expression levels were markedly decreased by DHA injection. Moreover, Western blotting showed that Bax, cleaved caspase-3 and CHOP were notably increased in the NaIO3 group but were significantly decreased by DHA injection. Collectively, intravitreal injection of DHA is safe and effective in select doses in a NaIO3-induced AMD rat model. The current results suggest that intravitreal injection of DHA may be a new avenue for the treatment of AMD.