A cancer vaccine with dendritic cells differentiated with GM-CSF and IFNα and pulsed with a squaric acid treated cell lysate improves T cell priming and tumor growth control in a mouse model

Abstract

Introduction: Ovarian cancer is one of the most lethal gynecologic cancers. Relapses after remission are common, hence novel strategies are urgently needed. Our group has previously developed a vaccination approach based on dendritic cells pulsed with HOCl-oxidized tumor lysates. Here we investigate the improvement of this vaccine strategy using squaric acid treatment of cancer cells during tumor lysate preparation and by differentiating dendritic cells in the presence of GM-CSF and IFNα. Methods: Induction of cell death by squaric acid treatment was assessed with propidium iodide (PI) and Annexin V in ID8 tumor cells. High mobility group box 1 (HMGB1) immunogenic status was analyzed using a western blot-based method, as previously described. For immunological tests, ID8 cells expressing ovalbumin (ova-ID8) were treated with squaric acid before cell lysis. DCs prepared with the canonical GM-CSF and IL-4 differentiation cocktail or IFNα and GM-CSF were pulsed with tumor cell lysates and further matured in the presence of IFNγ and LPS (4-DCs and α-DCs respectively). DCs were then used in co-culture assays with ova-specific T cells and IFNγ and IL-4 secretion measured by ELISA. DC phenotypes were characterized by FACS. Finally, DCs were tested in an ovarian cancer mouse model measuring body weight and animal survival. Results: Squaric acid treatment of mouse ovarian cancer cells induced tumor cell death as well as preserve HMGB1, a crucial Damage-associated molecular pattern (DAMP) signal, in its active reduced form. Squaric acid treatment of ID8-ova cells increased IFNγ and decreased IL-4 production from ova-specific T cells in co-culture experiments, promoting a more immunogenic cytokine secretion pattern. DCs differentiated in the presence of IFNα induced a considerable decrease in IL-4 production compared to canonical 4-DCs, without affecting IFNγ release. DC phenotyping demonstrated a more mature and immunogenic phenotype for IFNα-differentiated DCs. Vaccination in tumor-bearing mice showed that IFNα-differentiated DCs pulsed with squaric acid-treated lysates were the most potent at delaying tumor growth, improving animal survival. Conclusion: We identified squaric acid as a novel immunogenic treatment of tumor cells for cancer vaccines particularly efficient in prolonging animal survival when used in combination with IFNα-differentiated DCs. These promising results support future efforts for the clinical translation of this approach.

The immune enhancement effects of recombinant NDV expressing chicken granulocyte-macrophage colony-stimulating factor on the different avian influenza vaccine subtypes

“…Therefore, it is extremely important to add adjuvant to enhance the immune effects of vaccines to prolong the immune cycle. The enhanced immune function of GM-CSF has been confirmed in many studies (Dey, Chellappa, & Pathak, 2017;Mookerjee, Graciotti, & Kandalaft, 2018). GM-CSF can stimulate the activation and maturation of DCs, which are the most effective antigen presenting cells in the immune system (Ma, Lee, & Liu, 2017).…”

Deciphering the Mechanisms of Improved Immunogenicity of Hypochlorous Acid-Treated Antigens in Anti-Cancer Dendritic Cell-Based Vaccines

“…In order to map modifications at the amino acid level induced by HOCl oxidation, we followed an optimized protocol previously used by our group in clinical vaccination studies, by incubating for one hour A375 melanoma tumor cells in the presence of HOCl, followed by six cycles of freeze/thaw to generate the WTL [ 16 , 31 , 32 ]. These studies showed, in fact, that using this WTL preparation as an antigen source efficiently increased tumor antigen uptake by mo-DCs and vaccine-induced tumor protective effects, compared to the not-oxidized control counterpart [ 16 , 31 , 32 ]. We then subjected this lysate (Ox-L) to shotgun proteomic analysis by mass spectrometry (MS).…”

Pathogenicity of Helicobacter pylori in cancer development and impacts of vaccination

“…Vaccines have been developed against a large number of infectious and non-infectious diseases [94]. Early attempts focused on the recombinant urease showed some promising outcomes in animals, nevertheless, some subsequent clinical trials were hampered by a number of certain side effects of mucosal adjuvants [95].…”