A NEW MULTI SPECIALITY JOURNAL
Welcome to Era's Journal of Medical Research Center
From the Editor's Desk
miRNA AND CANCER METASTASIS
The simple perception that cancer killed a patient because it had spread, is not simple, rather is too
complicated to be fully understood till date. This was revealed ļrst by the investigators who were trying to
investigate this process in detail. The idea that tumor cells got deposited in the nearby areas by direct access
and to distant organs via blood stream was again found to be a simplistic conclusion. A deeper insight on the
process exposed the shallowness of our thinking because body's tissue and cell network were too dense to
allow any cell to just get-in, in its midst and/or allow a simple walking or strolling of a malignant rogue
amongst it's domain.
The next level of metastasis riddle was as to why in most tumors, the cells metastasize to certain speciļc organ-sites. But why at speciļc sites only a cancer deposits its cells. In 1889, Stephan Paget's had proposed a hypothesis (seed and soil theory) revolving around soil (speciļc organ) and seed (cancer cell) theory. Today this has been given a different perspective: āit is due to micro-environmentā of that organ or tissue where the cancer cells deposits and thrive. However which factors precisely govern this mechanism, needs further investigations.
As if this all was not enough trouble to bother the scientiļc investigators, some bright mind showed that this activity and process is not only at local level but, there is a high command (very much like in political parties), which ļnally sends its dictat transmitted through its messengers, that is genetic material here in the form of DNAs, RNAs and miRNA which controls signals.
Moreover, these malignant cells, like terrorist in our society, not only followed pre-determined sets of rules in shape of modules; but also moved singly and independently like lone wolf; hid amidst normal people (cells and tissues here), dare to survive in adversaries, kept increasing its capacity and capability, then strike at best amplitude when nobody was suspecting.
This migration of single and independent tumor malignant cell takes place in the very early course of the malignant tumor's life cycle.
Now, where do we stand today with all this early speculations and insights gained We now know for sure that we could not treat or completely eradicate some malignant tumors because sometimes our troops of medicines could not kill all the tumor cells, rather some cells quietly escape, in the very early stage of a malignant tumors development, hid and wait for circumstances to become right to re-emerge.
Thus the tumor metastasis has come to be understood as a very complex process, controlled by genetic domain in the body through micro-RNAs which either up-regulate or down-regulate the suppresser or proto-onco gene.
There are genes and local micro-environmental factors which help via āEpithelial myo- epithelial transmissionā, (EMT) and/or its reverse process, āmyo-epithelial transmission (MET).
These tumor cells have surface receptors as markers which help in these on-going processes.
There are substances, molecules and signals which loosen the tight web network between cells to allow these malignant cells to move. There are still other substances which disrupt the intact basement membranes which act like a wall preventing cells to move away.
Paradoxically at times our own chemotherapeutic management helps create favorable environment for tumor cells to grow after developing resistance.
Therefore to understand tumor metastatic process more and more investigations are needed through biochemical and molecular biology studies, associated with genetic processes including micro- RNA based control and epigenetic inļuences governing metabolic pathways regulated by miRNAs.
Prof. A.N. Srivastava
Era's Lucknow Medical College & Hospital, Lucknow
Prof. A.N. Srivastava (Editor in Chief ) View in PDF