Gefitinib-resistant (G-R) nonsmall-cell lung cancer (NSCLC) and rheumatoid arthritis (RA) were studied as conditions representative of malignant and proliferative diseases, respectively. Strong lipogenic activity and high expression of sterol regulatory element-binding protein 1 (SREBP1) were found in both G-R NSCLC cells and synovial fibroblasts from RA patients (RASFs). Berberine (BBR), an effective suppressor of SREBP1 and lipogenesis regulated through reactive oxygen species (ROS)/AMPK pathway, selectively inhibited the growth of G-R NSCLC cells and RASFs but not that of normal cells. It effectively caused mitochondrial dysfunction, activated ROS/AMPK pathway, and finally suppressed cellular lipogenesis and cell proliferation. Addition of ROS blocker, AMPK inhibitor, and palmitic acid significantly reduced the effect of BBR. In an in vivo study, treatment of BBR led to significant inhibition of mouse tumor xenograft growth and remarkably slowed down the development of adjuvant-induced arthritis in rats. Innovation and Conclusion: Targeting ROS/AMPK/lipogenesis signaling pathway selectively inhibited the growth of G-R NSCLC cells and the progress of RASFs in vitro and in vivo, which provides a new avenue for treating malignancies and proliferative diseases. Antioxid. Redox Signal. 28, 339-357.

Deltarasin is a recently identified small molecule that can inhibit KRAS–PDEδ interactions by binding to a hydrophobic pocket on PDEδ, resulting in the impairment of cell growth, KRAS activity, and RAS/RAF signaling in human pancreatic ductal adenocarcinoma cell lines. Since KRAS mutations are the most common oncogene mutations in lung adenocarcinomas, implicated in over 30% of all lung cancer cases, we examined the ability of deltarasin to inhibit KRAS-dependent lung cancer cell growth. Here, for the first time, we document that deltarasin produces both apoptosis and autophagy in KRAS-dependent lung cancer cells in vitro and inhibits lung tumor growth in vivo. Deltarasin induces apoptosis by inhibiting the interaction of with PDEδ and its downstream signaling pathways, while it induces autophagy through the AMPK-mTOR signaling pathway. Importantly, the autophagy inhibitor, 3-methyl adenine (3-MA) markedly enhances deltarasin-induced apoptosis via elevation of reactive oxygen species (ROS). In contrast, inhibition of ROS by N-acetylcysteine (NAC) significantly attenuated deltarasin-induced cell death. Collectively, these observations suggest that the anti-cancer cell activity of deltarasin can be enhanced by simultaneously blocking “tumor protective” autophagy, but inhibited if combined with an anti-oxidant.

In previous experiments, ginsenoside Rh2 induced apoptosis and cell cycle arrest, which indicates a potential role for ginsenoside Rh2 in anticancer treatment. The effect of ginsenoside Rh2 on cancer is marked and ginsenoside Rh2 has been shown to inhibit pancreatic tumor migratory ability. In the present study, Transwell chambers were used in order to investigate whether ginsenoside Rh2 inhibits the migratory ability of HepG2 liver carcinoma cells. Furthermore, to analyze activator protein 1 (AP-1) transcription factor expression following Rh2 treatment, ten plasmids encoding Renilla luciferase coupled to the transcription factors were transiently transfected into the HepG2 cells and luciferase was detected by the Luciferase Reporter Assay system reagent. The results indicated that ginsenoside Rh2 inhibited HepG2 cell migratory ability. The expression levels of AP-1 transcription factors were increased in HepG2 cells following induction by phorbol 12-myristate 13-acetate, but ginsenoside Rh2 suppressed this induced AP-1 expression. AP-1 transcription factors recruit histone deacetylase (HDAC)4 and affect its transcription, thus, the expression levels of HDAC4 were also analyzed, and these were found to be increased in the Rh2 treatment group. Matrix metalloproteinase 3 (MMP3), a gene downstream of AP-1, was then investigated, and the treatment group expressed reduced levels of MMP3 gene and protein. Therefore, the inhibitory effect of ginsenoside Rh2 on the migratory ability of HepG2 may be presumed to occur by the recruitment of HDAC and the resulting inhibition of AP-1 transcription factors, in order to reduce the expression levels of MMP3 gene and protein.

Oncogenic KRAS is considered a promising target for anti‐cancer therapy. However, direct pharmacological strategies targeting KRAS‐driven cancers remained unavailable. The prenyl‐binding protein PDEδ, a transporter of KRAS, has been identified as a potential target for pharmacological inhibitor by selectively binding to its prenyl‐binding pocket, impairing oncogenic KRAS signaling pathway. Here, we discovered a novel PDEδ inhibitor (E)‐N′‐((3‐(tert‐butyl)‐2‐hydroxy‐6,7,8,9‐tetrahydrodibenzo[b,dfuran‐1‐yl)methylene)‐2,4‐dihydroxybenzohydrazide(NHTD) by using a high‐throughput docking‐based virtual screening approach. In vitro and in vivo studies demonstrated that NHTD suppressed proliferation, induced apoptosis and inhibited oncogenic K‐RAS signaling pathways by disrupting KRAS‐PDEδ interaction in nonsmall cell lung cancer (NSCLC) harboring KRAS mutations. NHTD redistributed the localization of KRAS to endomembranes by targeting the prenyl‐binding pocket of PDEδ and exhibited the suppression of abnormal KRAS function. Importantly, NHTD prevented tumor growth in xenograft and KRAS mutant mouse model, which presents an effective strategy targeting KRAS‐driven cancer.

Background: Overexpression of epidermal growth factor receptor (EGFR) has been reported to be implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Several EGFR inhibitors have been used in clinical treatment of NSCLC, but the emergence of EGFRL858R/T790M resistant mutation has reduced the efficacy of the clinical used EGFR inhibitors. There is an urgent need to develop novel EGFRL858R/T790M inhibitors for better NSCLC treatment.Methods: By screening a natural product library, we have identified gossypol as a novel potent inhibitor targeting EGFRL858R/T790M. The activity of gossypol on NSCLC cells was evaluated by cell proliferation, cell apoptosis and cell migration assays. Kinase activity inhibition assay and molecular docking were used to study the inhibition mechanism of gossypol to EGFRL858R/T790M. Western blotting was performed to study the molecular mechanism of gossypol inhibiting the downstream pathways of EGFR.Results: Gossypol inhibited the cell proliferation and cell migration of NSCLC cells, and induced caspase-dependent cell apoptosis of NSCLC cells by upregulating the expression of pro-apoptotic protein BAD. Molecular docking revealed that gossypol could bind to the kinase domain of EGFRL858R/T790M with good binding affinity through hydrogen bonds and hydrophobic interactions. Gossypol inhibited the kinase activity of EGFRL858R/T790M with EC50 of 150.1 nM. Western blotting analysis demonstrated that gossypol inhibited the phosphorylation of EGFR and its downstream signal pathways in a dose-dependent manner.Conclusion: Gossypol inhibited cell proliferation and induced apoptosis of NSCLC cells by targeting EGFRL858R/T790M. Our findings provided a basis for developing novel EGFRL858R/T790M inhibitors for treatment of NSCLC.