Homospisulosine induced apoptosis in cervical carcinoma cells is associated with phosphorylation of Bcl-2 and up-regulation of p27/Kip1

Spisulosine (1-deoxysphinganine) is a sphingoid amino alcohol isolated from the sea clams that showed potent antiproliferative activity against a broad spectrum of solid tumors but failed in clinical trials due to neurotoxicity. However, its structural similarity to other bioactive sphingoids, interesting mode of action, and appreciable potency against cancer cells make it a suitable lead for future anticancer drug development. The present study was conducted to elucidate mechanisms of the antiproliferative/cytotoxic effects of newly synthesized spisulosine analog homospisulosine (KP7). The evaluation was performed on cervical carcinoma cells, representing an in vitro model of one of the most common cancer types and a significant worldwide cause of women's cancer mortality. Treatment with homospisulosine (2.0 μM) for 24, 48, and 72 h significantly inhibited the growth of HeLa cells in vitro and induced apoptosis detectable by DNA fragmentation, externalization of phosphatidylserine, dissipation of mitochondrial membrane potential, activation of caspase-3 and cleavage of PARP. In addition, treating HeLa cells with spisulosine increased p27 and Bcl-2 on protein levels and phosphorylation of Bcl-2 on Ser70 residue. These results support the potential for spisulosine analogs represented here by homospisulosine for future therapeutic development.

Involvement of Both Extrinsic and Intrinsic Apoptotic Pathways in Tridecylpyrrolidine-Diol Derivative-Induced Apoptosis In Vitro

Despite the decreasing trend in mortality from colorectal cancer, this disease still remains the third most common cause of death from cancer. In the present study, we investigated the antiproliferative and pro-apoptotic effects of (2S,3S,4R)-2-tridecylpyrrolidine-3,4-diol hydrochloride on colon cancer cells (Caco-2 and HCT116). The antiproliferative effect and IC₅₀ values were determined by the MTT and BrdU assays. Flow cytometry, qRT-PCR and Western blot were used to study the cellular and molecular mechanisms involved in the induction of apoptotic pathways. Colon cancer cell migration was monitored by the scratch assay. Concentration-dependent cytotoxic and antiproliferative effects on both cell lines, with IC₅₀ values of 3.2 ± 0.1 μmol/L (MTT) vs. 6.46 ± 2.84 μmol/L (BrdU) for HCT116 and 2.17 ± 1.5 μmol/L (MTT) vs. 1.59 ± 0.72 μmol/L (BrdU), for Caco-2 were observed. The results showed that tridecylpyrrolidine-induced apoptosis was associated with the externalization of phosphatidylserine, reduced mitochondrial membrane potential (MMP) accompanied by the activation of casp-3/7, the cleavage of PARP and casp-8, the overexpression of TNF-α and FasL and the dysregulation of Bcl-2 family proteins. Inhibition of the migration of treated cells across the wound area was detected. Taken together, our data show that the anticancer effects of tridecylpyrrolidine analogues in colon cancer cells are mediated by antiproliferative activity, the induction of both extrinsic and intrinsic apoptotic pathways and the inhibition of cell migration.

Jaspine B Hydrochloride-induced Apoptosis in HeLa Cells Is Associated With Disrupted Sphingolipid Metabolism and Ceramide Overload

BACKGROUND/AIM

A series of experiments on HeLa cells were conducted to provide new information concerning the anti-cancer properties of jaspine B hydrochloride (JBH).

MATERIALS AND METHODS

HeLa cells treated with 0.5 μmol/l JBH for 24, 48, and 72 h underwent flow cytometric analysis of the cell cycle, and measurement of phosphatidylserine externalization, mitochondrial membrane potential (MMP), casp-3 activation, cleavage of PARP, ceramide levels, aSMase activity, and Bcl-2 release. nSMase activity was measured by a colorimetric assay. Gene expression was determined by qRT-PCR. Immunocytochemistry was performed to detect p21 and p27 expression.

RESULTS

JBH-induced apoptosis in HeLa cells associated with externalization of phosphatidylserine, reduced MMP, activation of casp-3, and cleavage of PARP as well as up-regulation of TNF-α, FasL, and casp-8. Significant increase in nSMase activity, ceramide levels, Bcl-2 release (predominantly in the inactive form), and pro-apoptotic nuclear localization of p21 and p27 were also detected.

CONCLUSION

JBH-induced apoptosis in HeLa cells is associated with disrupted sphingolipid homeostasis resulting in increased ceramide levels.

New chalcone derivative exhibits antiproliferative potential by inducing G2/M cell cycle arrest, mitochondrial-mediated apoptosis and modulation of MAPK signalling pathway

In the present study, we investigated antiproliferative activity of seven newly synthesized chalcone derivatives. Among tested compounds, (2 E)-3-(acridin-9-yl)-1-(2,6-dimethoxyphenyl)prop-2-en-1-one (1C) was the most potent with IC₅₀ = 4.1 μmol/L in human colorectal HCT116 cells and was selected for further studies. Inhibition of cell proliferation was associated with cell cycle arrest in G2/M phase and dysregulation of α, α1 and β5 tubulins. Moreover, 1C caused disruption of the mitochondrial membrane potential and increased number of cells with sub G0/G1 DNA content which is considered as marker of apoptosis. Apoptosis was confirmed by annexin V/PI and AO/PI staining. Furthermore, we found increased concentration of cytochrome c, Smac/Diablo and increased caspase-3 and caspase-9 activity, cleavage of PARP as well as activation of DNA repair mechanisms in 1C-treated HCT116 cancer cells. Moreover this chalcone derivative up-regulated proapoptotic Bax expression and down-regulated antiapoptotic Bcl-2 and Bcl-xL expression. Additionally, 1C treatment led to modulation of MAPKs and Akt signalling pathways. In conclusion, our data showed ability of 1C to suppress cancel cell growth and provide the rationale for further in vivo study.