Targeting CD8+T cells with natural products for tumor therapy: Revealing insights into the mechanisms

Background: Despite significant advances in cancer immunotherapy over the past decades, such as T cellengaging chimeric antigen receptor (CAR) -T cell therapy and immune checkpoint blockade (ICB), therapeutic failure resulting from various factors remains prevalent. Therefore, developing combinational immunotherapeutic strategies is of great significance for improving the clinical outcome of cancer immunotherapy. Natural products are substances that naturally exist in various living organisms with multiple pharmacological or biological activities, and some of them have been found to have anti -tumor potential. Notably, emerging evidences have suggested that several natural compounds may boost the anti -tumor effects through activating immune response of hosts, in which CD8 + T cells play a pivotal role. Methods: The data of this review come from PubMed, Web of Science, Google Scholar, and ClinicalTrials (https:// clinicaltrials.gov/) with the keywords "CD8 + T cell", "anti -tumor", "immunity", "signal 1", "signal 2", "signal 3", "natural products", "T cell receptor (TCR)", "co -stimulation", "co -inhibition", "immune checkpoint", "inflammatory cytokine", "hesperidin", "ginsenoside", "quercetin", "curcumin", "apigenin", "dendrobium officinale polysaccharides (DOPS)", "luteolin", "shikonin", "licochalcone A", "erianin", "resveratrol", "procyanidin", "berberine", "usnic acid", "naringenin", "6-gingerol", "ganoderma lucidum polysaccharide (GL -PS)", "neem leaf