Regulation of Extracellular HMGB-1 Alarmin Levels by CIGB-300 Anticancer Peptide In Vitro and In Vivo

HMGB-1 is an alarmin representative of DAMP playing a central role in immunogenic cell death (ICD), a necessary condition in the dialog established between dying tumor cells and the immune system during some anticancer therapies. Therefore, early screening for ICD inducers represents a major priority in drug development today. In this work, we investigated the effect elicited by the clinical-grade CIGB-300 peptide, which impairs Protein Kinase CK2-mediated phosphorylation and other CK2 signaling connected kinases. Here, HMGB-1 extracellular release was investigated in an 18-cell line panel from blood malignancies, uterine-cervical cancer and NSCLC treated with CIGB-300 at equipotent doses (IC50) over 24 h. Interestingly, CIGB-300 treatment upregulated the HMGB-1 protein levels at the culture supernatant in most of the cell lines (p = 0.01) and fold-change increases ≥ 2 were associated with intrinsic cell line sensitivity towards CIGB-300’s cytotoxic effect. However, the HMGB-1 release by CIGB-300 was context-specific with clear induction on blood and uterine-cervical cancer cells and a diffused response pattern in NSCLC. Importantly, CIGB-300 treatment of blood cancer patients enrolled in a Phase I study induced plasma HMGB-1 alarmin in 4 out of 7 subject who received the entire treatment plan. Altogether, our data reveal for the first time that CIGB-300 treatment is able to induce extracellular HMGB-1 release in vitro and in vivo which could be indicative of ICD induction in some kinds of tumors; furthermore, the induction of extracellular HMGB-1 alarmin as a putative CIGB-300 response biomarker merits further investigation.