Functionalised Ligand-Based Nanomaterial Drug Targeting Approaches for Colorectal Cancer Therapy

Cancer refers to a condition in which abnormal cells uncontrollably divide, resulting in the destruction of tissues. In colorectal cancer, uncontrolled cell proliferation takes place in the rectum or colon. Most colorectal tumors start as adenomas, a form of polyp that can develop into cancer within the rectum or colon. Symptoms of colorectal cancer include chronic diarrhea or constipation, bleeding from the rectum, bloody stools, change in appetite, weight loss, etc. Risk factors associated with colorectal cancer are smoking, obesity, and low physical activity. Colorectal cancer can be treated depending on size, location, and the spread of the cancer. Treatment includes surgery where the lymph node is dissected and a colectomy is performed. Chemotherapy and radiation therapies are other treatment options, but the main disadvantage is that these treatments have nonspecific avenues. Apart from killing cancerous cells, they damage healthy cells, too. Therefore, with the help of nanotechnology, drug-containing nanoparticles can be created with the aid of nanocarriers, which are stronger, more durable, and site-specific. The cancerous cells can be actively targeted by formulating nanoparticles loaded with anticancer drugs and functionalising the surface by either attaching ligands (peptides, antibodies, and small molecules) or targeting molecules towards receptors that are present on the exterior surface of the cancerous cells. These surfaces functionalised nanoparticles, loaded with anticancer drugs, are significantly upregulated in cancerous cells in contrast to healthy surrounding cells and tissues. This review article is focused on ligand-based drugs targeting colorectal tumours.