3-(4-chlorophenyl)-adamantane-1-carboxylic-acid-(pyridin-4-ylmethyl)amide and Lung-Neoplasms

There is an urgent need to improve efficacy of chemotherapeutics to overcome resistance in cancer treatment. Sphingosine kinase-2 (SphK2) a key regulator of sphingolipid signaling has been rationalized as an important therapeutic target. We evaluated the role of SphK2 in doxorubicin (DOX)-induced apoptosis of NSCLC cells via altering c-FLIPS, MCL-1 and survivin expressions in order to overcome chemoresistance.. Proliferation and apoptosis were evaluated by MTT assay and DAPI staining, respectively. Cell population in each phase of cell cycle was determined by flow cytometric assay. Gene and protein expression levels were examined by quantitative RT-PCR and western blot analysis, respectively.. Phorbol myristate acetate (PMA), a SphK2 stimulator, decreased cell death induced by IC. Identifying cancer patients with high SphK2 expression and then inhibiting of SphK2 activity can be considered as an important strategy to increase the efficacy of DOX in the induction of apoptosis.

Topics: A549 Cells; Adamantane; Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Survival; Doxorubicin; Drug Resistance, Neoplasm; Drug Synergism; Humans; Inhibitor of Apoptosis Proteins; Lung Neoplasms; Myeloid Cell Leukemia Sequence 1 Protein; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Pyridines; Survivin; Tetradecanoylphorbol Acetate

Non-small cell lung cancer (NSCLC) accounts for about 85-90% of lung cancer cases, and is the number one killer among cancers in the United States. The majorities of lung cancer patients do not respond well to conventional chemo- and/or radio-therapeutic regimens, and have a dismal 5-year survival rate of ∼15%. The recent introduction of targeted therapy and immunotherapy gives new hopes to NSCLC patients, but even with these agents, not all patients respond, and responses are rarely complete. Thus, there is still an urgent need to identify new therapeutic targets in NSCLC and develop novel anti-cancer agents. Sphingosine kinase 2 (SphK2) is one of the key enzymes in sphingolipid metabolism. SphK2 expression predicts poor survival in NSCLC patients, and is associated with Gefitinib-resistance. In this study, the anti-NSCLC activities of ABC294640, the only first-in-class orally available inhibitor of SphK2, were explored. The results obtained indicate that ABC294640 treatment causes significant NSCLC cell apoptosis, cell cycle arrest and suppression of tumor growth in vitro and in vivo. Moreover, lipidomics analyses revealed the complete signature of ceramide and dihydro(dh)-ceramide species in the NSCLC cell-lines with or without ABC294640 treatment. These findings indicate that sphingolipid metabolism targeted therapy may be developed as a promising strategy against NSCLC.

Topics: A549 Cells; Adamantane; Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Cycle Checkpoints; Cell Growth Processes; Ceramides; Humans; Lung Neoplasms; Mice; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Pyridines; Random Allocation; Xenograft Model Antitumor Assays

Sphingosine kinase 2 (SphK2) is proposed as a novel oncotarget for lung cancer. Here, we studied the anti-lung cancer cell activity by ABC294640, a first-in-class SphK2 inhibitor. We showed that ABC294640 suppressed growth of primary and A549 human lung cancer cells, but sparing SphK2-low lung epithelial cells. Inhibition of SphK2 by ABC294640 increased ceramide accumulation, but decreased pro-survival sphingosine-1-phosphate (S1P) content, leading to lung cancer cell apoptosis activation. Significantly, we show that glucosylceramide synthase (GCS) might be a major resistance factor of ABC294640. The GCS inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) or GCS shRNA/siRNA knockdown facilitated ABC294640-induced ceramide production and lung cancer cell apoptosis. Reversely, forced overexpression of GCS reduced ABC294640's sensitivity, resulting in decreased ceramide accumulation and apoptosis induction in A549 cells. These findings provide further evidences to support that targeting SphK2 by ABC294640 may be a rational treatment option for lung cancer. Ceramide glucosylation inhibition may further sensitize lung cancer cells to ABC294640.

Topics: A549 Cells; Adamantane; Antineoplastic Agents; Apoptosis; Cell Proliferation; Ceramides; Drug Resistance, Neoplasm; Glucosyltransferases; Humans; Lung; Lung Neoplasms; Phosphotransferases (Alcohol Group Acceptor); Pyridines

Evidences suggest that tumor microenvironment may play an important role in cancer drug resistance. Sphingosine kinase 2 (SphK2) is proposed to be the key regulator of sphingolipid signaling. This study is aimed to investigate whether the combination of molecular targeting therapy using a specific inhibitor of SphK2 (ABC294640), with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can enhance the apoptosis of non-small cell lung cancer (NSCLC) cells. Our results revealed that NSCLC cells' sensitivity to TRAIL is correlated with the level of SphK2. Compared with TRAIL alone, the combination therapy enhanced the apoptosis induced by TRAIL, and knockdown of SphK2 by siRNA presented a similar effect. Combination therapy with ABC294640 increased the activity of caspase-3/8 and up-regulated the expression of death receptors (DR). Additional investigations revealed that translocation of DR4/5 to the cell membrane surface was promoted by adding ABC294640. However, expression of anti-apoptosis proteins such as Bcl(-)2 and IAPs was not significantly modified by this SphK2 inhibitor. Overall, this work demonstrates that SphK2 may contribute to the apoptosis resistance in NSCLC, thus indicating a new therapeutic target for resistant NSCLC cells.

Topics: Adamantane; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Molecular Targeted Therapy; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Protein Transport; Pyridines; Receptors, TNF-Related Apoptosis-Inducing Ligand; TNF-Related Apoptosis-Inducing Ligand