curcumin and dactolisib

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that integrates nutrients to execute cell growth. We hypothesized that mTOR is influential in the intervertebral disc-largest avascular, low-nutrient organ. Our objective was to identify the optimal mTOR inhibitor for treating human degenerative disc disease.. mTOR complex 1 (mTORC1) regulates p70/ribosomal S6 kinase (p70/S6K), negatively regulates autophagy, and is controlled by Akt. Akt is controlled by phosphatidylinositol 3-kinase (PI3K) and mTOR complex 2 (mTORC2). mTORC1 inhibitors-rapamycin, temsirolimus, everolimus, and curcumin, mTORC1&mTORC2 inhibitor-INK-128, PI3K&mTOR inhibitor-NVP-BEZ235, and Akt inhibitor-MK-2206-were applied to human disc nucleus pulposus (NP) cells. mTOR signaling, autophagy, apoptosis, senescence, and matrix metabolism were evaluated.. mTORC1 inhibitors decreased p70/S6K but increased Akt phosphorylation, promoted autophagy with light chain 3 (LC3)-II increases and p62/sequestosome 1 (p62/SQSTM1) decreases, and suppressed pro-inflammatory interleukin-1 beta (IL-1β)-induced apoptotic terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity (versus rapamycin, 95% confidence interval (CI) -0.431 to -0.194; temsirolimus, 95% CI -0.529 to -0.292; everolimus, 95% CI -0.477 to -0.241; curcumin, 95% CI -0.248 to -0.011) and poly (ADP-ribose) polymerase (PARP) and caspase-9 cleavage, senescent senescence-associated beta-galactosidase (SA-β-gal) positivity (versus rapamycin, 95% CI -0.437 to -0.230; temsirolimus, 95% CI -0.534 to -0.327; everolimus, 95% CI -0.485 to -0.278; curcumin, 95% CI -0.210 to -0.003) and p16/INK4A expression, and catabolic matrix metalloproteinase (MMP) release and activation. Meanwhile, dual mTOR inhibitors decreased p70/S6K and Akt phosphorylation without enhanced autophagy and suppressed apoptosis, senescence, and matrix catabolism. MK-2206 counteracted protective effects of temsirolimus. Additional disc-tissue analysis found relevance of mTOR signaling to degeneration grades.. mTORC1 inhibitors-notably temsirolimus with an improved water solubility-but not dual mTOR inhibitors protect against inflammation-induced apoptosis, senescence, and matrix catabolism in human disc cells, which depends on Akt and autophagy induction.

Topics: Adult; Aged; Aged, 80 and over; Apoptosis; Autophagy; Benzoxazoles; beta-Galactosidase; Cellular Senescence; Curcumin; Everolimus; Extracellular Matrix; Female; Heterocyclic Compounds, 3-Ring; Humans; Imidazoles; Inflammation; Male; Matrix Metalloproteinases; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Microtubule-Associated Proteins; Middle Aged; Nucleus Pulposus; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyrimidines; Quinolines; Ribosomal Protein S6 Kinases, 70-kDa; Sequestosome-1 Protein; Sirolimus

The PI3K/Akt and mTOR signaling pathways are important for cell survival and growth, and they are highly activated in cancer cells compared with normal cells. Therefore, these signaling pathways are targets for inducing cancer cell death. The dual PI3K/Akt and mTOR inhibitor NVP-BEZ235 completely inhibited both signaling pathways. However, NVP-BEZ235 had no effect on cell death in human renal carcinoma Caki cells. We tested whether combined treatment with natural compounds and NVP-BEZ235 could induce cell death. Among several chemopreventive agents, curcumin, a natural biologically active compound that is extracted from the rhizomes of Curcuma species, markedly induced apoptosis in NVP-BEZ235-treated cells. Co-treatment with curcumin and NVP-BEZ235 led to the down-regulation of Mcl-1 protein expression but not mRNA expression. Ectopic expression of Mcl-1 completely inhibited curcumin plus NVP-NEZ235-induced apoptosis. Furthermore, the down-regulation of Bcl-2 was involved in curcumin plus NVP-BEZ235-induced apoptosis. Curcumin or NVP-BEZ235 alone did not change Bcl-2 mRNA or protein expression, but co-treatment reduced Bcl-2 mRNA and protein expression. Combined treatment with NVP-BEZ235 and curcumin reduced Bcl-2 expression in wild-type p53 HCT116 human colon carcinoma cells but not p53-null HCT116 cells. Moreover, Bcl-2 expression was completely reversed by treatment with pifithrin-α, a p53-specific inhibitor. Ectopic expression of Bcl-2 also inhibited apoptosis in NVP-BE235 plus curcumin-treated cells. In contrast, NVP-BEZ235 combined with curcumin did not have a synergistic effect on normal human skin fibroblasts and normal human mesangial cells. Taken together, combined treatment with NVP-BEZ235 and curcumin induces apoptosis through p53-dependent Bcl-2 mRNA down-regulation at the transcriptional level and Mcl-1 protein down-regulation at the post-transcriptional level.

Topics: Apoptosis; Blotting, Western; Carcinoma, Renal Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Curcumin; DNA Fragmentation; Flow Cytometry; Humans; Imidazoles; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Quinolines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Signal Transduction; TOR Serine-Threonine Kinases