Secretion of Sphinganine by Drug-Induced Cancer Cells and Modified Mimetic Sphinganine (MMS) as c-Src Kinase Inhibitor.

BACKGROUND: Cancer cells exhibit selective metabolic reprogramming to promote proliferation, invasiveness, and metastasis. Sphingolipids such as sphingosine and sphinganine have been reported to modulate cell death processes in cancer cells. However, the potential of extracellular sphinganine and its mimetic compounds as inducers of cancer cell death has not been thoroughly investigated. METHODS: We obtained extracellular conditioned medium from HCT-116 cells treated with the previously reported anticancer composition, goat urine DMSO fraction (GUDF). The extracellular metabolites were purified using a novel and in-house developed vertical tube gel electrophoresis (VTGE) technique and identified through LC-HRMS. Extracellular metabolites such as sphinganine, sphingosine, C16 sphinganine, and phytosphingosine were screened for their inhibitory role against intracellular kinases using molecular docking. Molecular dynamics (MD) simulations were performed to study the inhibitory potential of a novel designed modified mimetic sphinganine (MMS) (Pubchem CID: 162625115) upon c-Src kinase. Furthermore, inhibitory potential and ADME profile of MMS was compared with luteolin, a known c-Src kinase inhibitor. RESULTS: Data showed accumulation of sphinganine and other sphingolipids such as C16 sphinganine, phytosphingosine, and ceramide (d18:1/14:0) in the extracellular compartment of GUDF-treated HCT-116 cells. Molecular docking projected c-Src kinase as an inhibitory target of sphinganine. MD simulations projected MMS with strong (-7.1 kcal/mol) and specific (MET341, ASP404) binding to the inhibitory pocket of c-Src kinase. The projected MMS showed comparable inhibitory role and acceptable ADME profile over known inhibitors. CONCLUSION: In summary, our findings highlight the significance of extracellular sphinganine and other sphingolipids, including C16 sphinganine, phytosphingosine, and ceramide (d18:1/14:0), in the context of drug-induced cell death in HCT-116 cancer cells. Furthermore, we demonstrated the importance of extracellular sphinganine and its modified mimetic sphinganine (MMS) as a potential inhibitor of c-Src kinase. These findings suggest that MMS holds promise for future applications in targeted and combinatorial anticancer therapy.

Reduced Level of Prolylhydroxyproline in the Nail Clippings of Oral Cancer Patients and its Role as an Activator of Phospholipase C-ß2.

BACKGROUND: The oral cancer microenvironment plays an important role in the development and progression of the disease which depicts the heterogeneous nature of diseases. Several cellular and non-cellular factors, including dipeptides, have been reported to drive tumor progression and metastasis. Among various secreted molecules in the tumor microenvironment, prolylhydroxyproline (Pro-Hyp) is a collagen-degraded product with specific relevance to fibrosis and oral cancer. However, the detection of Pro-Hyp in the nails of oral cancer patients is a potential biomarker, and our understanding of the biological relevance of Pro-Hyp is highly limited. METHODS: Here, the authors have attempted to use a novel and in-house vertical tube gel electrophoresis (VTGE) protocol to evaluate the level of Pro-Hyp in the nails of oral cancer patients and healthy subjects. Furthermore, we employed molecular docking and molecular dynamics (MD) simulations to predict the biological function of Pro-Hyp. ADME profiles such as the druglikeness and leadlikeness of Pro-Hyp and a known PLC-ß2 activator, m-3M3FBS, were evaluated by the SWISS-ADME server. RESULTS: We report that among various key metabolites, Pro-Hyp, a dipeptide, is reduced in the nails of oral cancer patients. Molecular docking and MD simulations helped to suggest the potential role of Pro-Hyp as an activator of Phospholipase C-ß2 (PLC-ß2). Pro-Hyp displayed good binding affinity (-7.6 kcal/mol) with specific interactions by a conventional hydrogen bond with key residues, such as HIS311, HIS312, VAL641, and GLU743. MD simulations showed that the activator binding residues and stability of complexes are similar to the well-known activator m-3M3FBS of PLC-ß2. ADME profiles such as the druglikeness and leadlikeness of Pro-Hyp were found to be highly comparable and even better than those of m-3M3FBS. CONCLUSION: This study is one of the first reports on Pro-Hyp as a metabolite biomarker in the nails of oral cancer patients. Furthermore, the implications of Pro-Hyp are proposed to activate PLC-ß2 as a pro-tumor signaling cascade. In the future, diagnostic and therapeutic approaches may be explored as biomarkers and mimetic of Pro-Hyp.