The Therapeutic Application of RBAC in Cancer

Growing evidence suggests that the adaptive cytotoxic cells have prophylactic effects as they work more proficiently in the early phases of tumor development, whereas the innate cellular system acts more curatively in parallel with disease progression. However, both cellular systems depend on the balance of the innate immune system, in which the degree of pre-activation (priming) and polarity play an important role. Tumor-induced dysregulation of the innate immune system leads to decreased function of type 1 effector cells and a predominance of type 2 cells, promoting the development of tumors. Consequently, we must learn to manipulate this regulation by increasing the type 1 innate immune effector activity and diminishing the type 2 system. This balance can also play an important role in the sensitivity of tumor cells to innate effectors (such as natural killer cells), which are regulated by the expressions of stress-related receptors on tumor cells (such as MICA, MICB, or ULBP 1-3). Rice bran arabinoxylan compound (RBAC) has been shown to activate the type 1 effector cells given in doses of 10-45 mg/kg and, in a controlled clinical trial, was able to result in an evidence-based antitumor effect. Case reports suggest that a combination of RBAC with therapy modalities that increase the expression of stress-related molecules on tumor cells (using growth factor receptor inhibitors or lower doses of gemcitabine) can result in remarkable clinical results. Therefore, if we learn to better manipulate the immunoregulation using standardized RBAC together with appropriate oncological treatments, it may open new strategies in tumor therapy.