Overcoming Biological Barriers and Drug Resistance Through Next-Generation Nanotherapeutic Delivery in Gastric Cancer.

Gastric cancer (GC) is one of the most aggressive malignancies with a dismal prognosis, late diagnosis, and limited therapy efficacy. Biologically, GC is associated with multiple barriers to therapeutic response including gastric mucosal layer, acidic tumor microenvironment (TME), high accumulation of extracellular matrix (ECM) components, and limited penetration depth of anticancer drugs into tumor tissue. Furthermore, inherent or acquired drug resistance associated with drug efflux transporters, deregulated autophagy, tumor heterogeneity, and cell survival pathways severely compromise treatment response. Nanotechnology has been widely used to develop next-generation nanotherapeutic delivery systems to overcome these biological barriers. Currently available nanoplatforms such as liposomes, polymeric nanoparticles, dendrimers, and inorganic nanocarriers have improved drug loading capacity, aqueous solubility, circulation time stability, tumor-targeted delivery, and sustained release of chemotherapeutics. Smart and stimuli-responsive nanocarriers can also take advantage of pathological hallmarks of tumors including low pH, redox potential, and overexpressed enzymes for enhanced selective delivery to the tumor site. Nanotherapeutics have also shown promise for co-delivery of multiple therapeutic agents to overcome drug resistance, manipulation of TME, and suppression of autophagy and apoptosis signaling pathways associated with drug resistance. This review discusses recent advances in nanotherapeutics for GC including approaches to overcome biological barriers and drug resistance and highlights translational gaps for clinical development.