Anti Cancer Drugs Essay Example | Topics and Well Written Essays - 500 words

Anti Cancer Drugs - Essay Example Cell cycle phase specific anticancer drugs are given for a particular phase and inhibit the further progression of the tumor cell (Ajithkumar et al 2011). The G1 phase specific drugs inhibit the G1 phase of the tumor cells and have therapeutic consequences associated with them. Cyclin-dependant kinases play an important role in the progression of the G1 phase. During the G1 to S phase transition, the phosphorylation of retinoblastoma susceptibility gene, Rb, regulated by D-type cyclins and CDKs 4 and 6 is a major factor causing the cell cycle progression. By inhibiting the CDK activity, the G1 phase activity can be inhibited as well. First generation CDK inhibitors include flavopiridol, UCN-01 and L86 8276, a non-chlorinated chemical form of flavopiridol. Flavopiridol causes G1 inhibition by its inhibitory action on the CDK 2 and CDK4. UCN-01 and flavopiridol cell cycle repression is followed by apoptosis of the tumor cells and they cave a cytotoxic effect. However, tumor cell selectivity is a major issue in their therapeutic affectivity. Non-tumor cells can also be affected by these anticancer drugs leading to apoptosis and hence, non-tumor cells are also sensitive for the CDK inhibiting action (Shapiro & Harper 1999). The limited inhibition activity caused by first-generation lead to the formulation of purvalanol B a second generation CDK inhibitor. This drug targets the ATP-binding sites and has shown higher selectivity for the CDKs. The activity of CDK4 and CDK 2 is inhibited 100-folds more selectively causing inactivation of Rb gene and ultimately cell arrest at the G1 phase (Shapiro & Harper 1999). Corticosteroids and natural products like asparagine are also specific for cell arrest at G1 phase of the tumor cells. Corticosteroids are effective in lymphoid derived tumors while asparagines are effective in depriving the tumor cells