Say No to Survivin'

It's a Protein Molecule that Stimulates Cancerous Growth

For all-round success in cancer treatment we still have a long way to go; partially effective therapies leading to relapses, are major problems faced by oncologists. Recent findings show that a protein molecule, survivin, helps cancer cells avoid death and stimulates tumour growth. This protects them from chemo-therapy. New researches have focused on ways in which survivin can be suppressed to check tumour growth.

Survivin is expressed in minute amounts in differentiated cells because it allows them to divide and grow by inhibiting cell death. Its effect is the most pronounced in cancerous cells where it is produced in large amounts, allowing them to grow rapidly.

Roland Stauber and colleagues at the Mainz University, Germany, showed that survivin can be suppressed by increasing nitric oxide (NO) levels which are otherwise produced in small quantities by cells. The amount of NO has been found to be inversely proportional to that of survivin. In other words, low levels of NO promote the function of survivin. High levels inhibit it, causing cancer cells to die.

Stauber promoted the idea of using NO as an anti-cancer drug. However, the team observed that high levels of NO killed regular, non-malignant cells as well. Stauber then proposed a combination of therapies in which the production of NO is completely blocked so that it cannot affect the survivin level and the remaining amount of survivin is suppressed with an inhibitor. The study was published in the November 2008 issue of the International Journal of Cancer.

Rajarshi Kar, from the Department of Biochemistry at the All India Institute of Medical Sciences, Delhi, is also working on the protein molecule. He found that survivin reduces the action of Paclitaxel, a prominent anti-cancer drug. Paclitaxel acts by arresting cell development, eventually triggering cell death. Survivin does the opposite, rendering Paclitaxel ineffective.

Kar noted that inhibiting survivin in cancerous cells resulted in 30 per cent cell death. This increased the efficiency of Paclitaxel. Kar also discovered that curcumin, a principal component of turmeric, reduces survivin levels. His research includes testing the effect of curcumin, with Paclitaxel and Carboplatin—a drug that inflicts dna damage—on cancer cell death.

Although further assessment is required, a step closer to victory would definitely entail regulating the production of survivin.


Down To Earth, February 2009