Advances in synthesis and biological evaluation of CDK2 inhibitors for cancer therapy.

One of the leading causes of mortality in the world is cancer. This disease occurs when responsible genes that regulate the cell cycle become inactive due to internal or external factors. Specifically, the G1/S and S/G2 transitions in the cell cycle are controlled by a protein called cyclin-dependent kinase 2 (CDK2). CDKs, which play a crucial role in managing the cell cycle, have been a wide area of research in cancer treatment. Over the past 11 years, significant research has been made in identifying potent, targeted, and efficient inhibitors of CDK2. In this summary, we have summarized recent developments in the synthesis and biological evaluation of CDK2 inhibitors.

Estimation of boswellic acids from market formulations of Boswellia serrata extract and 11-keto beta-boswellic acid in human plasma by high-performance thin-layer chromatography.

A rapid and sensitive high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the quantitative estimation of boswellic acids in formulation containing Boswellia serrata extract (BSE) and 11-keto beta-boswellic acid in human plasma. Simple extraction method was used for isolation of boswellic acid from formulation sample and acidified plasma sample. The isolated samples were chromatographed on silica gel 60F(254)-TLC plates, developed using ternary-solvent system (hexane-chloroform-methanol, 5:5:0.5, v/v) and scanned at 260 nm. The linearity range for 11-KBA spiked in 1 ml of plasma was 29.15-145.75 ng with average recovery of 91.66%. The limit of detection and limit of quantification for 11-KBA in human plasma were found to be 8.75 ng/ml and 29.15 ng/ml. The developed method was successfully applied for the assay of market formulations containing BSE and to determine plasma level of 11-keto beta-boswellic acid in a clinical pilot study.

Gangliosides regulate tumor cell adhesion to collagen.

The ability of tumor cells to adhere to extracellular matrix proteins is critical for migration and invasion. The factors that regulate tumor cell adhesion are poorly characterized. Gangliosides promote platelet adhesion and may also play a role in the adhesion of other cell types. We hypothesized that pharmacological depletion of membrane gangliosides from adherent cells would abrogate adhesion to collagen and promote migration and invasion. To test these hypotheses, LA-N1 neuroblastoma cells, which avidly adhere to collagen and are rich with membrane gangliosides (43.69 nmol/10(8) cells), were cultured in the presence of D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol-HCl. Endogenous gangliosides were reduced by 98% (0.76 nmol/10(8) cells) and adhesion to collagen decreased by 67%. There were no changes in cell morphology, viability, proliferation rate or apoptosis. Pre-incubation of ganglioside-depleted cells in conditioned medium from control cells restored adhesion to collagen (0.45 +/- 0.002), comparable to that of control cells (0.49 +/- 0.035). Similarly, pre-incubation of ganglioside-depleted cells with purified GD2 completely restored adhesion in a concentration-dependent manner. When LA-N1 cells were cultured with retinoic acid, a biological response modifier known to increase endogenous gangliosides, adhesion to collagen increased. Next, we questioned whether changes in adhesion would be reflected as changes in migration and invasion. Cells depleted of endogenous cellular gangliosides migrated more than control cells. Finally, control cells replete with their endogenous gangliosides demonstrated less invasive potential than control cells. The data demonstrate that endogenous tumor gangliosides increase neuroblastoma cell adhesion to collagen and reduce migration and invasion in vitro.

c-myc proto-oncogene expression in hemophilic synovitis: in vitro studies of the effects of iron and ceramide.

Hemophilia is a rare congenital bleeding disorder that is due to the deficiency of blood coagulation factor VIII or IX. Recurrent musculoskeletal bleeding is common and bleeding into joints results in a chronic inflammatory condition termed hemophilic synovitis. This destructive process is characterized by hemosiderin deposition in the superficial and deeper layers of the synovial membrane as well as a proliferation of synovial fibroblasts and vascular cells. The hyperplastic synovium and neovascular changes are reminiscent of the histopathologic appearance observed in malignant tissues. Indeed, the benign hyperplastic synovium in patients with hemophilia displays similar invasive and destructive behaviors suggesting the possibility of analogous disturbances in growth control and locally invasive mechanisms. Iron plays a role in malignant cell growth, local invasion, and tumor progression, possibly due to changes in the expression of the proto-oncogene, c-myc. We hypothesized that iron plays a similar role in hemophilic synovitis. To explore this hypothesis, we investigated the in vitro effects of iron on the proliferation of a primary, human synovial fibroblast cell (HSFC) line and the involvement of c-myc in this process. We also examined the role of ceramide, a sphingolipid capable of inducing apoptosis in this model system. HSFC proliferation was increased in a dose-dependent fashion and c-myc expression was enhanced by ferric citrate compared to sodium citrate control. Ceramide prevented both the iron-induced increases in HSFC proliferation and c-myc expression. These results indicate that iron probably plays a role in the proliferative changes observed in hemophilic joint disease and that aberrant expression of c-myc may underlie the iron effects. Furthermore, these results suggest that there may be a therapeutic role for ceramide in reversing these changes.