Cancer diseases affecting many organs of human body have caused a major
concern among the people all over the world. The conventional anticancer drugs,
although have given some relief in the patient conditions, still cannot provide reliable
treatment. Moreover, these drugs produce side effects in patients and in the worse
cases, the problem of rising resistance phenomena against such drugs gradually put the
patients’ lives even in more serious situation. Therefore, identifying and introducing
compounds with new identities to produce effective treatment with low side effects are
highly demanded. Small peptides with anticancer activity have been shown to fulfill
this demand. Peptides, with naturally or synthetic origin, have several advantages over
common drug molecules such as low toxicity, low immunogenicity, amenable to
several changes in their sequences and thus giving various homologues or analogues.
Moreover, peptides in conjugation with heterocyclic active compounds and/or known
anticancer drugs may result in molecules with new identities which show both benefits
of individual components within their unit structures. In this regard, peptide conjugates
may play a role, not only as anticancer agents but also as cell-membrane penetrating
and/ or cell targeting agents to help direct cancerous tissue internalization of the known
anticancer agents, and so, preventing or lowering the incidence of side effects of the
anticancer drugs on healthy tissues. In this chapter on the basis of several experiments,
information about various peptide categories, their analogues and conjugation with
other bioactive compounds is given. The discussion is focused on the anticancer
activity of peptides, those primarily known for other biological activities.
Understanding the cause of these activities may help to find out and make clearer the
mechanism of anticancer activity of the peptides.
Keywords: Anticancer, Bioactive compounds, Cell-membrane penetrating, Cell
targeting agents, Peptides, Peptide conjugation.