Chennai: Auto immune diseases, cancer, Type II diabetes, Parkinson’s and Alzheimer’s diseases are only a few ailments, among many, that cause immense fear among the public.
In a major breakthrough to help in the cure of these diseases, Yoshinori Ohsumi, from Japan, found that autophagy - a fundamental process for degrading and recycling cellular components, exists in yeast cells. Oshumi, during his research –the result of which was published in 1992, cultured altered yeast, lacking vacuolar degradation enzymes and simultaneously stimulated autophagy by starving the cells. Within hours, the yeast sacks were filled with small vesicles that had not been degraded. The sacks were basically cells undergoing autophagy.
Oshumi, therefore found a method to identify and characterise key genes involved in this process. His research findings, for which he won a Nobel prize, have generated much interest in the science behind the biological process.
“As with a tow truck carrying cargo waste to the dump yard, the cell uses special structures called autophagosomes to carry large cellular wastes to the lysosomes for degradation by a process of autophagosis, which literally translates to ‘eating self’. It is necessary because a cell has many components that are meant to play a role only on ad-hoc basis,” said PhD student Samu John.
“Everything in a cell is controlled through a master structure called the DNA, which codes for proteins of every type including the proteins that are necessary for autophagy. If the coding of these in the DNA is affected through mutations, then the cargo cannot be dismantled and therefore, they accumulate, thereby affecting other functions of the cells and deleteriously affecting the cell cycle regulation, leading to cancer, Type II diabetes, auto immune diseases and the like,” he explained.
“In cancer, it is of future use and a novel target model. Disturbances in the autophagic machinery have also been linked to cancer,” said Dr Anita Ramesh, Professor, Department of Oncology, Saveetha Medical College and Hospital.
Autophagy modulation can be applied to cancer therapy and autophagy inhibitors enable tumour eradication. “In the adjuvant setting and after eliminating a large proportion of tumour by radiation and chemotherapy, the remaining cells can reside in a disrupted and stressed environment, susceptible to inhibition of the autophagy survival mechanism,” she added. With autophagy, doctors now hope the burden of diseases to go down.
