Ad-KDRscFv:sTRAIL displays a synergistic antitumor effect without obvious cytotoxicity to normal tissues

Apoptosis-Inducing TNF Superfamily Ligands for Cancer Therapy

Cancer is a complex disease with apoptosis evasion as one of its hallmarks; therefore, apoptosis induction in transformed cells seems a promising approach as a cancer treatment. TNF apoptosis-inducing ligands, which are naturally present in the body and possess tumoricidal activity, are attractive candidates. The most studied proteins are TNF-α, FasL, and TNF-related apoptosis-inducing ligand (TRAIL). Over the years, different recombinant TNF family-derived apoptosis-inducing ligands and agonists have been designed. Their stability, specificity, and half-life have been improved because most of the TNF ligands have the disadvantages of having a short half-life and affinity to more than one receptor. Here, we review the outlook on apoptosis-inducing ligands as cancer treatments in diverse preclinical and clinical stages and summarize strategies of overcoming their natural limitations to improve their effectiveness.

rmhTNF-α combined with cisplatin inhibits proliferation of A549 cell line in vitro

OBJECTIVE

To explore the inhibitory effect of recombinant mutant human tumor necrosis factor-Α (rmhTNF-Α) in combination with cisplatin on human lung adenocarcinoma cell line A549.

METHODS

Human lung adenocarcinoma cell line A549 was treated with varying concentrations of rmhTNF-Α (0.38, 0.75, 1.50, 6.00 and 12.00 IU/ml) or cisplatin (3.91, 7.81, 15.63, 31.25 and 62.50 Μg/ml) for 24 hours. Viable cell number was analyzed by using crystal violet staining. The inhibitory rates of A549 cells growth by the two drugs were calculated. For analyzing whether there was a synergistic effect of rmhTNF-Α with cisplatin, A549 cells were treated with 0.75 IU/ml rmhTNF-Α and increased concentrations of cisplatin.

RESULTS

rmhTNF-Α or cisplatin inhibited the growth of A549 cell lines in a dose-dependent manner. The inhibitory effect of rmhTNF-Α combined with cisplatin was significantly greater than cisplatin alone at the same concentration (all P<0.01).

CONCLUSION

rmhTNF-Α combined with cisplatin might have synergistic inhibitory effect on human lung adenocarcinoma cell line A549.

Sodium nitroprusside (SNP) sensitizes human gastric cancer cells to TRAIL-induced apoptosis

AIM

To investigate the effects of the nitrous oxide (NO)-donor sodium nitroprusside (SNP) on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in human gastric cancer cells.

METHODS

The MTT assay and flow cytometry were used to detect cellular proliferation and markers of apoptosis, respectively. Expression levels of caspases-8, and 9 were determined by Western blot. Changes in Nitric Oxide Synthase (NOS) activity, NO production, and caspase activation were also evaluated.

RESULTS

We found that TRAIL induced apoptosis and cell cycle arrest in human gastric cancer cell lines, and that this effect was mediated by NO production, and activation of both the extrinsic and intrinsic signaling pathways of apoptosis. In addition, we found that the NO-donor SNP sensitizes gastric cancer cells to TRAIL-mediated apoptosis. Treatment of cells with both TRAIL and SNP resulted in increased activation of caspase-8 and caspase-9 and NO release. Inhibition of caspase-8 blocked cell TRAIL-induced apoptosis, while a selective caspase-9 inhibitor was unable to prevent apoptosis induced by either TRAIL or TRAIL plus SNP. Inhibition of NOS could block the activation of caspase-9, but had no obvious effect on cell apoptosis.

CONCLUSIONS

SNP-sensitized gastric cancer cells to TRAIL-induced cytotoxicity by stimulating the release of NO, in turn facilitating the mitochondria-mediated signal transduction pathway. The engagement of the mitochondria signaling pathways along with the TRAIL death receptor signaling pathway synergistically increase levels of apoptosis in these cells.