22-O-(N-Boc-L-glycine) ester of renieramycin M inhibits migratory activity and suppresses epithelial-mesenchymal transition in human lung cancer cells

Modulation of hypoxia-inducible factor-1 signaling pathways in cancer angiogenesis, invasion, and metastasis by natural compounds: a comprehensive and critical review

Tumor cells employ multiple signaling mediators to escape the hypoxic condition and trigger angiogenesis and metastasis. As a critical orchestrate of tumorigenic conditions, hypoxia-inducible factor-1 (HIF-1) is responsible for stimulating several target genes and dysregulated pathways in tumor invasion and migration. Therefore, targeting HIF-1 pathway and cross-talked mediators seems to be a novel strategy in cancer prevention and treatment. In recent decades, tremendous efforts have been made to develop multi-targeted therapies to modulate several dysregulated pathways in cancer angiogenesis, invasion, and metastasis. In this line, natural compounds have shown a bright future in combating angiogenic and metastatic conditions. Among the natural secondary metabolites, we have evaluated the critical potential of phenolic compounds, terpenes/terpenoids, alkaloids, sulfur compounds, marine- and microbe-derived agents in the attenuation of HIF-1, and interconnected pathways in fighting tumor-associated angiogenesis and invasion. This is the first comprehensive review on natural constituents as potential regulators of HIF-1 and interconnected pathways against cancer angiogenesis and metastasis. This review aims to reshape the previous strategies in cancer prevention and treatment.

Semisynthesis of 5-O-ester derivatives of renieramycin T and their cytotoxicity against non-small-cell lung cancer cell lines

The semisynthesis of 5-O-ester derivatives of renieramycin T was accomplished through the photoredox reaction of renieramycin M (1), a bistetrahydroisoquinolinequinone alkaloid isolated from the Thai blue sponge Xestospongia sp. This process led to the conversion of compound 1 to renieramycin T (2), which was subsequently subjected to Steglich esterification with appropriate acylating agents containing linear alkyl, N-tert-butoxycarbonyl-L-amino, and heterocyclic aromatic substituent. Notably, the one-pot transformation, combining the photoredox reaction and esterification led to the formation of 7-O-ester derivatives of renieramycin S due to hydrolysis. Subsequently, the in vitro cytotoxicity of the 17 semisynthesized derivatives against human non-small-cell lung cancer (NSCLC) cells in parallel with normal cell lines was evaluated. Among the tested compounds, 5-O-(3-propanoyl) ester of renieramycin T (3b) exhibited potent cytotoxic activity with half-maximal inhibitory concentration (IC50) values at 33.44 and 33.88 nM against H292 and H460 cell lines, respectively. These values were within the same range as compound 1 (IC50 = 34.43 and 35.63 nM) and displayed twofold higher cytotoxicity compared to compound 2 (IC50 = 72.85 and 83.95 nM). The steric characteristics and aromatic orientation of the 5-O-ester substituents played significant roles in their cytotoxicity. Notably, derivative 3b induced apoptosis with minimal necrosis, in contrast to the parental compound 1. Hence, the relationship between the structure and cytotoxicity of renieramycin-ecteinascidin hybrid alkaloids was investigated. This study emphasizes the potential of the series of 5-O-ester derivatives of renieramycin T as promising leads for the further development of potential anti-NSCLC agents.

Preclinical Characterization of 22-(4'-Pyridinecarbonyl) Jorunnamycin A against Lung Cancer Cell Invasion and Angiogenesis via AKT/mTOR Signaling

Non-small-cell lung cancer (NSCLC), the most prevalent form of lung cancer, is associated with an unfavorable prognosis owing to its high rate of metastasis. Thus, the identification of new drugs with potent anticancer activities is essential to improve the clinical outcome of this disease. Marine organisms exhibit a diverse source of biologically active compounds with anticancer effects. The anticancer effects of jorunnamycin A (JA) derived from the Thai blue sponge (Xestospongia sp.) and 22-(4'-pyridinecarbonyl) jorunnamycin A (22-(4'-py)-JA), the semisynthetic derivative of JA, have been reported. The present study aimed to investigate the impact of 22-(4'-py)-JA on NSCLC metastasis using in vitro, in vivo, and in silico approaches. The JA derivative inhibited tumor cell invasion and tube formation in human umbilical vein endothelial cells (HUVECs). The computational analysis demonstrated strong and stable interactions between 22-(4'-py)-JA and the AKT protein. Further examinations into the molecular mechanisms revealed the suppression of AKT/mTOR/p70S6K signaling by 22-(4'-py)-JA, leading to the downregulation of matrix metalloproteinases (MMP-2 and MMP-9), hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF). Furthermore, 22-(4'-py)-JA suppressed in vivo metastasis by decreasing the number of colonies in the lung. These findings indicated the antimetastasis activity of 22-(4'-py)-JA, which might prove useful for further clinical applications.

How do prolonged anchorage-free lifetimes strengthen non-small-cell lung cancer cells to evade anoikis? - A link with altered cellular metabolomics

BACKGROUND

Malignant cells adopt anoikis resistance to survive anchorage-free stresses and initiate cancer metastasis. It is still unknown how varying periods of anchorage loss contribute to anoikis resistance, cell migration, and metabolic reprogramming of cancerous cells.

RESULTS

Our study demonstrated that prolonging the anchorage-free lifetime of non-small-cell lung cancer NCI-H460 cells for 7 days strengthened anoikis resistance, as shown by higher half-life and capability to survive and grow without anchorage, compared to wild-type cells or those losing anchorage for 3 days. While the prolonged anchorage-free lifetime was responsible for the increased aggressive feature of survival cells to perform rapid 3-dimensional migration during the first 3 h of a transwell assay, no significant influence was observed with 2-dimensional surface migration detected at 12 and 24 h by a wound-healing method. Metabolomics analysis revealed significant alteration in the intracellular levels of six (oxalic acid, cholesterol, 1-ethylpyrrolidine, 1-(3-methylbutyl)-2,3,4,6-tetramethylbenzene, β-alanine, and putrescine) among all 37 identified metabolites during 7 days without anchorage. Based on significance values, enrichment ratios, and impact scores of all metabolites and their associated pathways, three principal metabolic activities (non-standard amino acid metabolism, cell membrane biosynthesis, and oxidative stress response) offered potential links with anoikis resistance.

CONCLUSIONS

These findings further our insights into the evolution of anoikis resistance in lung cancer cells and identify promising biomarkers for early lung cancer diagnosis.

Can Natural Products Targeting EMT Serve as the Future Anticancer Therapeutics?

Cancer is the leading cause of death and has remained a big challenge for the scientific community. Because of the growing concerns, new therapeutic regimens are highly demanded to decrease the global burden. Despite advancements in chemotherapy, drug resistance is still a major hurdle to successful treatment. The primary challenge should be identifying and developing appropriate therapeutics for cancer patients to improve their survival. Multiple pathways are dysregulated in cancers, including disturbance in cellular metabolism, cell cycle, apoptosis, or epigenetic alterations. Over the last two decades, natural products have been a major research interest due to their therapeutic potential in various ailments. Natural compounds seem to be an alternative option for cancer management. Natural substances derived from plants and marine sources have been shown to have anti-cancer activity in preclinical settings. They might be proved as a sword to kill cancerous cells. The present review attempted to consolidate the available information on natural compounds derived from plants and marine sources and their anti-cancer potential underlying EMT mechanisms.