Search

Background/Aim: Fine particulate matter (PM(2.5)) in air pollution causes skin damage through the induction of oxidative stress in the epidermis. Antioxidants help counteract cellular oxidant species and maintain cell homeostasis. This study aimed to examine the protective effect of standardized ethanolic extract of Thunbergia laurifolia leaves on PM(2.5)-mediated oxidative stress in epidermal keratinocytes. Materials and Methods: The extract was standardized with rosmarinic acid. Effects of standardized T. laurifolia extract (STLE) (0-400 μg/ml) and PM(2.5) (0-32 μg/ml) on cell viability after 24 h of treatment were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. PM(2.5) (0-32 μg/ml) induction of intracellular reactive oxygen species (ROS) at 6 h was monitored using 2’,7’-dichlorodihydrofluorescein diacetate. Cells were co-treated for 6 h with PM(2.5) (32 μg/ml) and STLE (25-100 μg/ml) and monitored for oxidative stress inhibition. Proteins related to cellular antioxidant defense system were examined by western blot analysis, after co-treatment and STLE treatment for 6 h and 24 h, respectively. Nuclear expression of nuclear factor erythroid 2-related factor (NRF2) and p62 were determined by immunofluorescence after co-treatment of 6 h. Results: PM(2.5) (32 μg/ml) remarkably induced ROS production within 6 h. The co-treatment dramatically inhibited PM(2.5)-induced oxidative stress at 6 h. In addition, STLE enhanced cellular defense system by increasing the levels of p62, NRF2 and superoxide dismutase 1 proteins. STLE stimulated nuclear localization and function of NRF2 and p62 proteins, while suppressing Kelch-like ECH-associated protein 1. Conclusion: STLE exhibits promising natural antioxidant activity against oxidative stress induced by PM(2.5) in keratinocytes.

Aberrant c-Myc is a common feature in the majority of human cancers and has been linked to oncogenic malignancies. As a profound activator of aggressive lung cancer, targeting c-Myc would lead to the better clinical outcome. Here we develop a novel c-Myc targeted compound N, N-bis (5-ethyl-2-hydroxybenzyl) methylamine (EMD) and present evidence demonstrating its effectiveness in targeting c-Myc for degradation in human lung carcinoma. EMD exhibited strong cytotoxicity towards various human lung cancer cell lines ae well as chemotherapeutic-resistant patient-derived lung cancer cells through apoptosis induction, in comparison to chemotherapeutic drugs. Mechanistically, EMD eliminates c-Myc in the cells and initiates caspase-dependent apoptosis cascade. Cycloheximide chase assay revealed that EMD significantly shortened c-Myc half-life by approximately two-fold. Cotreatment of EMD with proteasome inhibitor MG132 reversed its c-Myc targeting effect, suggesting the involvement of ubiquitin-mediated proteasomal degradation in the process. We further verified that EMD strongly induced the ubiquitination of c-Myc that prompted it for protein degradation. c-Myc inhibition and apoptosis induction were additionally shown in hematologic malignant K562, indicating the generality of the observed EMD effects. Altogether, we have identified EMD as a novel potent compound targeting oncogenic c-Myc, which may offer new opportunities for lung cancer treatment. SIGNIFICANCE STATEMENT Deregulation of c-Myc is frequently associated with cancer progression. This study examined the effect of a new compound EMD in targeting c-Myc in several lung cancer cell lines and drug-resistant primary lung cancer cells. EMD induced dramatic c-Myc degradation through ubiquitin-proteasomal mechanism. The promising anti-cancer and c-Myc targeted activities of EMD support its potential new approaches to treat c-Myc driven cancer.

Background/aim Certain integrins including integrin β3 facilitate movement and survival of metastatic cancer cells. We examined whether benzoxazine dimer analogue N,N-bis(5-ethyl-2-hydroxybenzyl) methylamine (HM) has anti-metastatic effects. Materials and methods Cell viability was examined by the 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. Wound healing and phalloidin-rhodamine assays were performed to evaluate the migration and filopodia formation, respectively. Anoikis resistance was studied by anchorage-independent growth assay. The expression of proteins regulating migration were examined by western blot. Results HM treatment significantly inhibited growth and survival of detached lung cancer cells as indicated by the reduced colony number and size of anchorage-independent growth analysis. HM inhibited cell migration and suppressed filopodia formation. Protein analysis indicated that the compound dramatically decreased integrin β3 and its related downstream proteins including active focal adhesion kinase (FAK) and active protein kinase B (AKT); however, integrin β1 and α5 were found to be unaltered. Conclusion HM shows a potential in targeting integrin β3 and could be a good candidate for further developed as an anti-metastatic therapy.

Cancer stem cells (CSCs) are distinct cancer populations with tumorigenic and self-renewal abilities. CSCs are drivers of cancer initiation, progression, therapeutic failure, and disease recurrence. Thereby, novel compounds targeting CSCs offer a promising way to control cancer. In this study, the hydroquinone 5-O-cinnamoyl ester of renieramycin M (CIN-RM) was demonstrated to suppress lung cancer CSCs. CIN-RM was toxic to lung cancer cells with a half-maximal inhibitory concentration of around 15 µM. CIN-RM suppressed CSCs by inhibiting colony and tumor spheroid formation. In addition, the CSC population was isolated and treated and the CSCs were dispatched in response to CIN-RM within 24 h. CIN-RM was shown to abolish cellular c-Myc, a central survival and stem cell regulatory protein, with the depletion of CSC markers and stem cell transcription factors ALDH1A1, Oct4, Nanog, and Sox2. For up-stream regulation, we found that CIN-RM significantly inhibited Akt and consequently decreased the pluripotent transcription factors. CIN-RM also inhibited mTOR, while slightly decreasing p-GSK3β (Ser9) but rarely affected the protein kinase C (PKC) signal. Inhibiting Akt/mTOR induced ubiquitination of c-Myc and promoted degradation. The mechanism of how Akt regulates the stability of c-Myc was validated with the Akt inhibitor wortmannin. The computational analysis further confirmed the strong interaction between CIN-RM and the Akt protein with a binding affinity of −10.9 kcal/mol at its critical active site. Taken together, we utilized molecular experiments, the CSC phenotype, and molecular docking methods to reveal the novel suppressing the activity of this compound on CSCs to benefit CSC-targeted therapy for lung cancer treatment.

Cancer stem cells (CSCs) are distinct cancer populations with tumorigenic and self-renewal abilities. CSCs are drivers of cancer initiation, progression, therapeutic failure, and disease recurrence. Thereby, novel compounds targeting CSCs offer a promising way to control cancer. In this study, the hydroquinone 5-O-cinnamoyl ester of renieramycin M (CIN-RM) was demonstrated to suppress lung cancer CSCs. CIN-RM was toxic to lung cancer cells with a half-maximal inhibitory concentration of around 15 µM. CIN-RM suppressed CSCs by inhibiting colony and tumor spheroid formation. In addition, the CSC population was isolated and treated and the CSCs were dispatched in response to CIN-RM within 24 h. CIN-RM was shown to abolish cellular c-Myc, a central survival and stem cell regulatory protein, with the depletion of CSC markers and stem cell transcription factors ALDH1A1, Oct4, Nanog, and Sox2. For up-stream regulation, we found that CIN-RM significantly inhibited Akt and consequently decreased the pluripotent transcription factors. CIN-RM also inhibited mTOR, while slightly decreasing p-GSK3β (Ser9) but rarely affected the protein kinase C (PKC) signal. Inhibiting Akt/mTOR induced ubiquitination of c-Myc and promoted degradation. The mechanism of how Akt regulates the stability of c-Myc was validated with the Akt inhibitor wortmannin. The computational analysis further confirmed the strong interaction between CIN-RM and the Akt protein with a binding affinity of −10.9 kcal/mol at its critical active site. Taken together, we utilized molecular experiments, the CSC phenotype, and molecular docking methods to reveal the novel suppressing the activity of this compound on CSCs to benefit CSC-targeted therapy for lung cancer treatment.

Focal adhesion kinase (FAK) controls several cancer aggressive potentials of cell movement and dissemination. As epithelial–mesenchymal transition (EMT) and the migratory-associated integrins, known influencers of metastasis, have been found to be linked with FAK activity, this study unraveled the potential pharmacological effect of artocarpin in targeting FAK resulting in the suppression of EMT and migratory behaviors of lung cancer cells. Treatment with artocarpin was applied at concentrations of 0–10 μM, and the results showed non-cytotoxicity in lung cancer cell lines (A549 and H460), normal lung (BEAS-2B) cells and primary metastatic lung cancer cells (ELC12, ELC16, and ELC20). We also found that artocarpin (0–10 µM) had no effect on cell viability, proliferation, and migration in BEAS-2B cells. For metastasis-related approaches, artocarpin significantly inhibited cell migration, invasion, and filopodia formation. Artocarpin also dramatically suppressed anchorage-independent growth, cancer stem cell (CSC) spheroid formation, and viability of CSC-rich spheroids. For molecular targets of artocarpin action, computational molecular docking revealed that artocarpin had the best binding affinity of −8.0 kcal/mol with FAK protein. Consistently, FAK-downstream proteins, namely active Akt (phosphorylated Akt), active mTOR (phosphorylated mTOR), and Cdc42, and EMT marker and transcription factor (N-cadherin, Vimentin, and Slug), were found to be significantly depleted in response to artocarpin treatment. Furthermore, we found the decrease of Caveolin-1 (Cav-1) accompanied by the reduction of integrin-αν and integrin-β3. Taken together, these findings support the anti-metastasis potentials of the compound to be further developed for cancer therapy.

Aberrant cellular Myc (c-Myc) is a common feature in the majority of human cancers and has been linked to oncogenic malignancies. Here, we developed a novel c-Myc-targeting compound

Emerging evidence has provided important information on oncoproteins involved in cancer initiation, progression, metastasis, and resistance to current therapies. C-myc, one of the critical oncoproteins, has been shown to be implicated in enhancing the aggressiveness of many cancers, mainly through its ability to increase cancer cell growth and cellular survival mechanisms. Despite the more precise and earlier detection and the availability of better therapies, lung cancer remains the most dreadful cancer as it causes high mortality rate with relatively poor treatment success. In lung cancer, C-myc is frequently dysregulated and associated with unfavorable patient survival. C-myc plays a role in regulation of lung cancer cell behaviors including growth, resistance, death, and dissemination through the activation of cell cycle driving proteins, an increase in the cellular levels of anti-apoptotic proteins, and the modulation of metabolism. Besides, C-myc has been shown to be important for cancer stem cell (CSC) properties. Taken together, targeting as well as inhibiting C-myc could provide promising means for resolving lung cancer. This review emphasizes on the molecular mechanism by which C-myc influences lung cancer growth, metastasis, drug resistance, and CSC maintenance, and suggests the target proteins that may benefit drug discovery and design.