LFG-500, a newly synthesized flavonoid, induced a reactive oxygen species-mitochondria-mediated apoptosis in hepatocarcinoma cells

Extract of Araçá-Boi and Its Major Phenolic Compound, Trans-Cinnamic Acid, Reduce Viability and Inhibit Migration of Human Metastatic Melanoma Cells

Cutaneous melanoma is an aggressive type of skin cancer that is recognized for its high metastatic potential and the challenges it presents in its treatment. There has been increasing interest in plant extracts and their potential applications in melanoma. The present study aimed to investigate the content of individual phenolic compounds in araçá-boi extract, evaluate their antioxidant activity, and explore their effects on cell viability, migration properties, oxidative stress levels, and protein expression in the human metastatic melanoma cell line SK-MEL-28. HPLC-DAD analysis identified 11 phenolic compounds in the araçá-boi extract. Trans-cinnamic acid was the main phenolic compound identified; therefore, it was used alone to verify its contribution to antitumor activities. SK-MEL-28 melanoma cells were treated for 24 h with different concentrations of araçá-boi extract and trans-cinnamic acid (200, 400, 600, 800, and 1600 µg/mL). Both the araçá-boi extract and trans-cinnamic acid reduced cell viability, cell migration, and oxidative stress in melanoma cells. Additionally, they modulate proteins involved in apoptosis and inflammation. These findings suggest the therapeutic potential of araçá-boi extract and its phenolic compounds in the context of melanoma, especially in strategies focused on preventing metastasis. Additional studies, such as the analysis of specific signaling pathways, would be valuable in confirming and expanding these observations.

Curcumin promotes apoptosis of human melanoma cells by caspase 3

Cutaneous melanoma (CM) is a malignant neoplasm with a high metastatic rate that shows poor response to systemic treatments in patients with advanced stages. Recently, studies have highlighted the antineoplastic potential of natural compounds, such as polyphenols, in the adjuvant therapy context to treat CM. The objective of the present study was to evaluate the effect of different concentrations of curcumin (0.1-100 µM) on the metastatic CM cell line SK-MEL-28. The cells were treated for 6 and 24 h with different concentrations of curcumin. Cell viability was assessed by 3-(4,5-dimethyl-2thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and fluorescence microscopy. The apoptotic-inducing potential was detected by annexin V flow cytometry. The wound healing assay was used to verify cell migration after the curcumin exposition. The redox profile was evaluated by levels of the pro-oxidant markers reactive oxygen species (ROS) and Nitric oxide (NOx) and antioxidants of total thiols (PSH) and nonprotein thiols. The gene expression and enzymatic activity of caspase 3 were evaluated by reverse transcription-quantitative polymerase chain reaction and a sensitive fluorescence assay, respectively. Curcumin significantly decreased the cell viability of SK-MEL-28 cells at both exposure times. It also induced apoptosis at the highest concentration tested (p < .0001). SK-MEL-28 cell migration was inhibited by curcumin after treatment with 10 µM (p < .0001) and 100 µM (p < .0001) for 6 and 24 h (p = .0006 and p < .0001, respectively). Furthermore, curcumin significantly increased levels of ROS and NOx. Finally, curcumin was capable of increasing the gene expression at 10 µM (p = .0344) and 100 µM (p = .0067) and enzymatic activity at 10 µM (p = .0086) and 100 µM (p < .0001) of caspase 3 after 24 h. For the first time, we elucidated in our study that curcumin increases ROS levels, promoting oxidative stress that activates the caspase pathway and culminates in SK-MEL-28 metastatic CM cell death.

LFG-500, a novel synthetic flavonoid, suppresses epithelial-mesenchymal transition in human lung adenocarcinoma cells by inhibiting NLRP3 in inflammatory microenvironment

Increasing evidence indicates that inflammatory microenvironment facilitates tumor metastasis. Here, we found that LFG-500, a novel synthetic flavonoid, significantly inhibited epithelial-mesenchymal transition (EMT) in human lung adenocarcinoma A549 and H1299 cells co-cultured with LPS-challenged THP-1 cells or cultured in THP-1 cell-derived conditioned medium. Moreover, we found that TNF-α is a direct and decisive factor for promoting EMT and LFG-500 suppressed TNF-α-induced EMT and cell motility. NLRP3 knockdown inactivated NLRP3 inflammasome, which subsequently inhibited EMT and blocked cell migration, indicating that TNF-α-induced EMT requires the NLRP3 inflammasome. LFG-500 inhibited the activation of the NLRP3 inflammasome, thus inhibiting EMT. Moreover, LFG-500 treatment significantly inhibited metastasis in vivo by downregulating NLRP3 expression. Importantly, we found that NLRP3 was highly expressed in high-grade lung adenocarcinoma and that its expression was correlated with lymph node metastasis. NLRP3 and vimentin levels were significantly increased in matched metastatic lymph nodes. Moreover, a significant positive correlation was observed between their levels. Together, these results suggest that LFG-500 markedly suppresses EMT by inhibiting the NLRP3 inflammasome in the inflammatory microenvironment and that NLRP3 is a potential biomarker of lung adenocarcinoma metastasis.

LFG-500, a newly synthesized flavonoid, induces apoptosis in human ovarian carcinoma SKOV3 cells with involvement of the reactive oxygen species-mitochondria pathway

Ovarian cancer is the main cause of gynecologic malignancy-related mortality in women. Therefore, the disease requires improvements in treatment options and in the potency of chemotherapeutic drugs. The study of apoptosis in tumor cells is an important field for cancer therapy and cancer molecular biology. It has recently been established that LFG-500, a new synthesized flavonoid with a piperazine and benzyl group substitution, has strong anticancer activity. However, its exact molecular mechanism is not fully understood. The present study aimed to examine the effects of LFG-500 on human ovarian cancer SKOV3 cells, as well as to identify its underlying mechanisms. The data showed that LFG-500 inhibited the growth of SKOV3 cells in a concentration-dependent manner. It was found that LFG-500 induced apoptosis in SKOV3 cells, detected by DAPI staining and an Annexin V/PI double-staining assay. Moreover, LFG-500 reduced caspase-3 protein expression and increased the Bcl-2-associated X protein/B-cell lymphoma 2 protein ratio. Further findings revealed that LFG-500 treatment resulted in reactive oxygen species (ROS) accumulation and loss of mitochondrial transmembrane potential. Collectively, these results demonstrated that LFG-500 efficiently induced apoptosis in SKOV3 cells, an event possibly associated with the trigging of the mitochondrial apoptotic pathway through ROS accumulation. Therefore, LFG-500 shows potential as a potent anticancer agent for the treatment of ovarian cancer.

LFG-500 inhibits the invasion of cancer cells via down-regulation of PI3K/AKT/NF-κB signaling pathway

Cancer cell invasion, one of the crucial events in local growth and metastatic spread of tumors, possess a broad spectrum of mechanisms, especially altered expression of matrix metalloproteinases. LFG-500 is a novel synthesized flavonoid with strong anti-cancer activity, whose exact molecular mechanism remains incompletely understood. This current study was designed to examine the effects of LFG-500 on tumor metastasis using in vitro and in vivo assays. LFG-500 could inhibit adhesion, migration and invasion of MDA-MB-231 human breast carcinoma cells. Meanwhile, it reduced the activities and expression of MMP-2 and MMP-9 via suppressing the transcriptional activation of NF-κB rather than AP-1 or STAT3. Moreover, LFG-500 repressed TNF-α induced cell invasion through inhibiting NF-κB and subsequent MMP-9 activity. Further elucidation of the mechanism revealed that PI3K/AKT but not MAPK signaling pathway was involved in the inhibitory effect of LFG-500 on NF-κB activation. LFG-500 could also suppress lung metastasis of B16F10 murine melanoma cells in vivo. Taken together, these results demonstrated that LFG-500 could block cancer cell invasion via down-regulation of PI3K/AKT/NF-κB signaling pathway, which provides new evidence for the anti-cancer activity of LFG-500.