1. Introduction
Depending on the type and condition of cancer, conventional treatments
may involve chemotherapy in combination with surgery, radiation therapy,
hormone therapy, and/or highly targeted therapies such as immunotherapy
and monoclonal antibody therapy. Chemotherapeutic drugs (synthetic,
semi-synthetic, and naturally occurring compounds) are cytotoxic and
often kill both cancerous and healthy cells, which are dividing rapidly.
Their main mode of action involves signaling through both death
receptors (extrinsic pathways) and mitochondrial pathways (intrinsic
pathways) and by inducing one or more apoptotic pathways.
Chemotherapeutic drugs can be classified by their mode of action into
alkylating antineoplastic agents, kinase inhibitors, aromatase
inhibitors, and topoisomerase inhibitors. Nature is an excellent and
useful source of anticancer agents, about 60% of which are extracted
from microorganisms, marine organisms, or plants (Iqbal et al., 2017).
Important anti-cancer phytochemicals include vinca alkaloids,
podophyllotoxin (PPT), taxol, camptothecin, and their derivatives.
These phyto-compounds are being used in various fields due to their
active role against different types of cancers and are preferred over
conventional chemotherapy due to their lesser. It is reported that 80%
of the population worldwide traditionally uses natural compounds
contained in medicinal plants, and more than 1800 experimentally
authenticated anti-cancer compounds-target interactions have been
documented at Naturally occurring Plant-based Anti-cancer
Compound-Activity-Target Database (NPACT)
(Aung et al., 2017).
There is a need for the continuous production of these compounds, which
may be achieved using a range of biotechnological approaches involving
the use of axenic plant cell and organ cultures. Moreover,
bioengineering and metabolic engineering approaches can be used to study
their biosynthetic pathways (Nobili et al., 2009). This review focuses
on state-of-the-art biotechnological approaches for the production of
effective anticancer compounds with a short description of their
chemical structure, mode of action, and biological activities.