Exploring the Anticancer Potential of Origanum majorana Essential Oil Monoterpenes Alone and in Combination against Non-Small Cell Lung Cancer.

Lung cancer is the second most commonly diagnosed cancer and has the highest mortality rate worldwide despite the remarkable advances in its treatment. Origanum majorana Essential Oil (OMEO) has been shown to be effective against non-small cell lung cancer (NSCLC) cells, decreasing their viability and colony growth in vitro, as well as inhibiting tumor growth in chick embryo chorioallantoic membranes (CAM) and nude mice in vivo. OMEO is mainly composed of four monoterpenes, namely terpinen-4-ol, sabinene hydrate, α-terpinene, and γ-terpinene. In this study, we aimed to investigate the potential anticancer effects of these monoterpenes, either alone or in combination, on NSCLC. Our findings indicate that these four monoterpenes significantly decreased NSCLC cell viability in a concentration-dependent manner, reduced their colony growth in vitro, and also downregulated survivin expression in these cells. Moreover, different combined mixtures of these monoterpenes further enhanced their anticancer effects on cellular viability, with a terpinen-4-ol and sabinene hydrate combination being the most potent. We also found that terpinen-4-ol, in combination with sabinene hydrate, markedly enhanced the anticancer effect of the individual monoterpenes on NSCLC viability within a shorter treatment duration through, at least in part, survivin downregulation. Furthermore, this combination enhanced the inhibition of colony growth in vitro and the tumor growth of NSCLC cells xenografted onto chick embryo CAM in vivo. Altogether, our study highlights the potential of these monoterpenes for use in further pre-clinical investigations against various cancer hallmarks.

PD-1 Independent Role of PD-L1 in Triple-Negative Breast Cancer Progression.

Triple-negative breast cancer (TNBC) is a type of breast malignancy characterized by a high proliferative rate and metastatic potential leading to treatment failure, relapse, and poor prognosis. Therefore, efforts are continuously being devoted to understanding its biology and identifying new potential targets. Programmed death-ligand 1 (PD-L1) is an immunosuppressive protein that inactivates T cells by binding to the inhibitory receptor programmed death-1 (PD-1). PD-L1 overexpression in cancer cells contributes to immune evasion and, subsequently, poor survival and prognosis in several cancers, including breast cancer. Apart from its inhibitory impact on T cells, this ligand is believed to have an intrinsic role in cancer cells. This study was performed to clarify the PD-1 independent role of PD-L1 in TNBC MDA-MB-231 cells by knocking out the PD-L1 using three designs of CRISPR-Cas9 lentiviral particles. Our study revealed that PD-L1 knockout significantly inhibited MDA-MB-231 cell proliferation and colony formation in vitro and tumor growth in the chick embryo chorioallantoic membrane (CAM) model in vivo. PD-L1 knockout also decreased the migration and invasion of MDA-MB-231 cells in vitro. We have shown that PD-L1 knockout MDA-MB-231 cells have low levels of p-Akt and p-ERK in addition to some of their downstream proteins, c-Fos, c-Myc, p21, survivin, and COX-2. Furthermore, PD-L1 knockout significantly decreased the expression of Snail and RhoA. This study shows the intrinsic role of PD-L1 in TNBC independently of its binding to PD-1 receptors on T cells. It may pave the way for developing novel therapeutic strategies using PD-L1 inhibitors alone and in combination to treat TNBC more effectively.

Origanum majorana essential oil decreases lung tumor growth and metastasis in vitro and in vivo.

Current targeted- and immuno-therapies have prolonged the overall survival of non-small cell lung cancer (NSCLC) patients by few months in a small percentage of patients responding to these treatments. This situation has prompted us to investigate the anticancer potential of the Origanum majorana Essential Oil (OMEO). In this pre-clinical study and using two major human NSCLC, namely A549 and LNM35, we demonstrated that OMEO significantly decreases the viability of these cells and the growth of their pre-formed colonies in vitro in a concentration-dependent manner and partly via the induction of caspase 3/7-dependent cell death and downregulation of survivin. Moreover, OMEO significantly slow down the growth of A549 and LNM35 tumor xenografts in the CAM and in nude mice models in vivo. Furthermore, OMEO significantly reduces in vitro A549 and LNM35 cancer cell migration and invasion, and the incidence and growth of lymph nodes metastasis in vivo in nude mice xenografted subcutaneously with the highly metastatic LNM35 cells. Three months of treatment of mice with OMEO did not affect blood, kidney, and liver functions. Our study demonstrates that OMEO is a safe and robust anticancer option.

Impact of Sodium Dichloroacetate Alone and in Combination Therapies on Lung Tumor Growth and Metastasis.

Metabolic reprogramming has been recognized as an essential emerging cancer hallmark. Dichloroacetate (DCA), an inhibitor of pyruvate dehydrogenase kinase (PDK), has been reported to have anti-cancer effects by reversing tumor-associated glycolysis. This study was performed to explore the anti-cancer potential of DCA in lung cancer alone and in combination with chemo- and targeted therapies using two non-small cell lung cancer (NSCLC) cell lines, namely, A549 and LNM35. DCA markedly caused a concentration- and time-dependent decrease in the viability and colony growth of A549 and LNM35 cells in vitro. DCA also reduced the growth of tumor xenografts in both a chick embryo chorioallantoic membrane and nude mice models in vivo. Furthermore, DCA decreased the angiogenic capacity of human umbilical vein endothelial cells in vitro. On the other hand, DCA did not inhibit the in vitro cellular migration and invasion and the in vivo incidence and growth of axillary lymph nodes metastases in nude mice. Treatment with DCA did not show any toxicity in chick embryos and nude mice. Finally, we demonstrated that DCA significantly enhanced the anti-cancer effect of cisplatin in LNM35. In addition, the combination of DCA with gefitinib or erlotinib leads to additive effects on the inhibition of LNM35 colony growth after seven days of treatment and to synergistic effects on the inhibition of A549 colony growth after 14 days of treatment. Collectively, this study demonstrates that DCA is a safe and promising therapeutic agent for lung cancer.

Butein and Frondoside-A Combination Exhibits Additive Anti-Cancer Effects on Tumor Cell Viability, Colony Growth, and Invasion and Synergism on Endothelial Cell Migration.

Despite the significant advances in targeted- and immuno-therapies, lung and breast cancer are at the top list of cancer incidence and mortality worldwide as of 2020. Combination therapy consisting of a mixture of different drugs taken at once is currently the main approach in cancer management. Natural compounds are extensively investigated for their promising anti-cancer potential. This study explored the anti-cancer potential of butein, a biologically active flavonoid, on two major solid tumors, namely, A549 lung and MDA-MB-231 breast cancer cells alone and in combination with another natural anti-cancer compound, frondoside-A. We demonstrated that butein decreases A549 and MDA-MB-231 cancer cell viability and colony growth in vitro in addition to tumor growth on chick embryo chorioallantoic membrane (CAM) in vivo without inducing any noticeable toxicity. Additionally, non-toxic concentrations of butein significantly reduced the migration and invasion of both cell lines, suggesting its potential anti-metastatic effect. We showed that butein anti-cancer effects are due, at least in part, to a potent inhibition of STAT3 phosphorylation, leading to PARP cleavage and consequently cell death. Moreover, we demonstrated that combining butein with frondoside-A leads to additive effects on inhibiting A549 and MDA-MB-231 cellular viability, induction of caspase 3/7 activity, inhibition of colony growth, and inhibition of cellular migration and invasion. This combination reached a synergistic effect on the inhibition of HUVECs migration in vitro. Collectively, this study provides sufficient rationale to further carry out animal studies to confirm the relevance of these compounds' combination in cancer therapy.

Effects of Diesel Exhaust Particles on Mouse Gastric Stem Cells.

Stem cells have attracted many scientists because of their unique properties and therapeutic applications. However, very little is known on the environmental toxins that could affect their biological features. This study focuses on the consequences of the exposure of a cell line representative of the mouse gastric stem/progenitor (mGS) cells to diesel exhaust particles (DEPs). These immortal cells were cultured using routine protocols. The DEPs were added to the culture media at 1, 10, and 100 µg/mL for 1 to 72 h. The cells were assayed for their viability, migration, oxidative stress, and the expression of genes specific for cell proliferation, pluripotency, and death. DEPs induced a reduction in the metabolic activity of mGS cells, only at a high concentration of 100 µg/mL. However, no significant effects were detected on cell migration, oxidative stress markers (glutathione and thiobarbituric acid reactive substances), and cell death related proteins/genes. Interestingly, these findings were associated with down-regulation of Notch 2 and 3 and Bmi-1 proteins and activation of STAT3 involved in the regulation of the fate of stem cells. In conclusion, this study demonstrates that mGS cells have some resistance to oxidative stress and apoptosis when exposed to DEPs at the expense of their stemness.

PTC-209 Anti-Cancer Effects Involved the Inhibition of STAT3 Phosphorylation.

Introduction: Lung, breast, and colorectal cancers are the leading causes of cancer-related deaths despite many therapeutic options, including targeted therapy and immunotherapies. Methods: Here, we investigated the impact of PTC-209, a small-molecule Bmi-1 inhibitor, on human cancer cell viability alone and in combination with anticancer drugs, namely, cisplatin, oxaliplatin, 5-fluorouracil, camptothecin, and Frondoside-A and its impact on cellular migration and colony growth in vitro and on tumor growth in ovo. Results: We demonstrate that PTC-209 causes a concentration- and time-dependent decrease in the cellular viability of lung cancer cells (LNM35 and A549), breast cancer cells (MDA-MB-231 and T47D), and colon cancer cells (HT-29, HCT8/S11, and HCT-116). Similarly, treatment with PTC-209 significantly decreased the growth of LNM35, A549, MDA-MB-231, and HT-29 clones and colonies in vitro and LNM35 and A549 tumor growth in the in ovo tumor xenograft model. PTC-209 at the non-toxic concentrations significantly reduced the migration of lung (LNM35 and A549) and breast (MDA-MB-231) cancer cells. Moreover, we show that PTC-209, at a concentration of 1 µM, enhances the anti-cancer effects of Frondoside-A in lung, breast, and colon cancer cells, as well as the effect camptothecin in breast cancer cells and the effect of cisplatin in lung cancer cells in vitro. However, PTC-209 failed to enhance the anti-cancer effects of oxaliplatin and 5-fluorouracil in colon cancer cells. Treatment of lung, breast, and colon cancer cells with PTC-209 (1 and 2.5 µM) for 48 h showed no caspase-3 activation, but a decrease in the cell number below the seeding level suggests that PTC-209 reduces cellular viability probably through inhibition of cell proliferation and induction of cell death via a caspase-3-independent mechanism. Molecular mechanism analysis revealed that PTC-209 significantly inhibited the STAT3 phosphorylation by decreasing the expression level of gp130 as early as 30 min post-treatment. Conclusion: Our findings identify PTC-209 as a promising anticancer agent for the treatment of solid tumors either alone and/or in combination with the standard cytotoxic drugs cisplatin and camptothecin and the natural product Frondoside-A.

SMARCAD1 in Breast Cancer Progression.

BACKGROUND/AIMS: Breast cancer is the most common cancer in women worldwide, and within this cancer type, triple-negative breast cancers have the worst prognosis. The identification of new genes associated with triple-negative breast cancer progression is crucial for developing more specific anti-cancer targeted therapies, which could lead to a better management of these patients. In this context, we have recently demonstrated that SMARCAD1, a DEAD/H box-containing helicase, is involved in breast cancer cell migration, invasion, and metastasis. The aim of this study was to investigate the impact of the stable knockdown of SMARCAD1 on human breast cancer cell progression. METHODS: Using two different designs of shRNA targeting SMARCAD1, we investigated the impact of the stable knockdown of SMARCAD1 on human breast cancer cell proliferation and colony growth in vitro and on tumour growth in chick embryo and nude mouse xenograft models in vivo using MDA-MB-231 (ER-/PR-/ HER2-) and T47D (ER+/PR+/-/HER2-) human breast cancer cell lines. RESULTS: We found that SMARCAD1 knockdown resulted in a significant decrease in breast cancer cell proliferation and colony formation, leading to the significant inhibition of tumour growth in both the chick embryo and nude mouse xenograft models. This inhibition was due, at least in part, to a decrease in IKKß expression. CONCLUSION: These results indicate that SMARCAD1 is involved in breast cancer progression and can be a promising target for breast cancer therapy.

Frondoside A Enhances the Anti-Cancer Effects of Oxaliplatin and 5-Fluorouracil on Colon Cancer Cells.

Over recent years, we have demonstrated that Frondoside A, a triterpenoid glycoside isolated from an Atlantic sea cucumber, has potent in vitro and in vivo anti-cancer effects against human pancreatic, breast, and lung cancer. We have also demonstrated that Frondoside A is able to potentiate and/or synergize the anti-cancer effects of major classical cytotoxic agents, namely, gemcitabine, paclitaxel, and cisplatin, in the treatment of pancreatic, breast, and lung cancer, respectively. This study evaluates the impact of Frondoside A alone and in combination with the standard cytotoxic drugs oxaliplatin and 5-fluorouracil (5-FU) in the treatment of colon cancer using three human colon cancer cell lines, namely, HT-29, HCT-116, and HCT8/S11. We demonstrate that Frondoside A, oxaliplatin, and 5-FU cause a concentration- and time-dependent reduction in the number of HT-29 colon cancer cells. A concentration of 2.5 µM of Frondoside A led to almost 100% inhibition of cell numbers at 72 h. A similar effect was only observed with a much higher concentration (100 µM) of oxaliplatin or 5-FU. The reduction in cell numbers by Frondoside A, oxaliplatin, and 5-FU was also confirmed in two other colon cancer cell lines, namely, HCT8/S11 and HCT-116, treated for 48 h. The combinations of low concentrations of these drugs for 48 h in vitro clearly demonstrated that Frondoside A enhances the inhibition of cell numbers induced by oxaliplatin or 5-FU. Similarly, such a combination also efficiently inhibited colony growth in vitro. Interestingly, we found that the inhibition of ERK1/2 phosphorylation was significantly enhanced when Frondoside A was used in combination treatments. Moreover, we show that Frondoside A and 5-FU, when used alone, induce a concentration-dependent induction of apoptosis and that their pro-apoptotic effect is dramatically enhanced when used in combination. We further demonstrate that apoptosis induction upon the treatment of colon cancer cells was at least in part a result of the inhibition of phosphorylation of the survival kinase AKT, leading to caspase-3 activation, poly (ADP-ribose) polymerase (PARP) inactivation, and consequently DNA damage, as suggested by the increase in the level of γH2AX. In light of these findings, we strongly suggest that Frondoside A may have a role in colon cancer therapy when used in combination with the standard cytotoxic drugs oxaliplatin and 5-FU.

Anti-cancer, immunoregulatory, and antimicrobial activities of the frog skin host-defense peptides pseudhymenochirin-1Pb and pseudhymenochirin-2Pa.

Pseudhymenochirin-1Pb (Ps-1Pb) and pseudhymenochirin-2Pa (Ps-2Pa) are host-defense peptides, first isolated from skin secretions of the frog Pseudhymenochirus merlini (Pipidae). Ps-1Pb and Ps-2Pa are highly cytotoxic (LC50<12 µM) against non-small cell lung adenocarcinoma A549 cells, breast adenocarcinoma MDA-MB-231 cells, and colorectal adenocarcinoma HT-29 cells but are also hemolytic against human erythrocytes (LC50=28±2 µM for Ps-1Pb and LC50=6±1 µM for Ps-2Pa). Ps-2Pa shows selective cytotoxicity for tumor cells (LC50 against non-neoplastic human umbilical vein (HUVEC) cells=68±2 µM). Ps-1Pb and Ps-2Pa (5 µg/mL) significantly inhibit production of the anti-inflammatory cytokine IL-10 and the multifunctional cytokine IL-6 from lipopolysaccharide (LPS)-stimulated peritoneal macrophages from C57BL/6 mice and enhance the production of the pro-inflammatory cytokine IL-23 from both unstimulated and LPS-stimulated macrophages. Ps-1Pb potently (MIC≤10 µM) inhibits growth of multidrug-resistant clinical isolates of the Gram-positive bacteria methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, and the Gram-negative bacteria Acinetobacter baumannii and Stenotrophomonas maltophilia. Ps-2Pa shows the same high potency (MIC≤10 µM) against the Gram-positive bacteria but is 2-4 fold less potent against the Gram-negative isolates. Ps-1Pb at 4×MIC kills 99.9% of Escherichia coli within 30 min and 99.9% of S. aureus within 180 min. In conclusion, cytotoxicity against tumor cells, cytokine-mediated immunomodulatory properties, and broad-spectrum antimicrobial activity suggest that the Ps-1Pb and Ps-2Pa represent templates for design of non-hemolytic analogs for tumor therapy and for treatment of infections in cancer patients produced by multidrug-resistant pathogens.