Low molecular weight hyaluronan-preconditioning of tumor-pulsed dendritic cells increases their migratory ability and induces immunity against murine colorectal carcinoma

RIZZO M; GARCIA M; PICCIONI F; RODRÍGUEZ A; MALVICINI M; KIPPES N; ATORRASAGASTI C; AQUINO JB; ALANIZ L; MAZZOLINI G

Congreso; 1º Congreso francés-argentino de Inmunología; 2010

Colorectal carcinoma (CRC) is one of the leading causes of cancer death worldwide and, unfortunately, there is no curative treatment for patients not amenable to surgical resection. Dendritic cells DC are the most potent specialized antigen-presenting cells, ex-vivo generated, tumor-antigen loaded mature DC are currently exploited to immunity against cancer. Hyaluronan (HA) is a glycosaminoglycan found in almost all tissues, its functions are size-dependent  and the LMW HA form has been shown to induce the expression of inflammatory genes in many types of cells including DC and was shown to stimulate T cell responses by activating DC. We have recently shown that systemic administration of LMW HA, significantly reduces CRC growth in vivo, response partially mediated by DC. To potentiate the ability of DC loaded with tumor lysate (DC/LT) to induce immunity against CRC in mice we aimed to study the effects of preconditioning DC with LMW HA for therapeutic vaccination. The antitumor effect of LMW HA ex vivo-stimulated DC was evaluated in an in vivo BALB/c CT26 CRC model. When these LMW HA-treated CRC tumor lysate-pulsed DC (DC/TL/LMW-HA) were administered to tumor-bearing mice, a potent antitumor response was observed when compared to DC pulsed with tumor lysate alone, significantly reduced tumor growth(p<0.05). We show that splenocytes from animals treated with DC/TL/LMW HA presented a higher proliferative capacity (8585 vs 5700 cpm), increased IFN gamma production (368+26pg/ml vs 284+17pg/ml )and secreted lower levels of IL10 (519±124pg/ml vs 863±202pg/ml) respect to DC/LT. Increased specific CTL responses were observed in DC/TL/LMW HA-treated animals (p<0,05). Preconditioning of DC/TL with LMW HA increased their ability to migrate in vitro  towards CCL19 and CCL21 (cell/field 34,25±1,99 vs 13,64±1,7; 32,8±1,8 vs 13,11±1,4) respect to DC/TL. In addition, LMW HA enhanced the in vivo DC recruitment to tumor-regional lymph nodes as was detected by bioluminescence imaging of life DiR-stained DC. Our results shown the immunostimulatory properties of LMW HA on DC loaded with tumor lysate that will be uses for cancer therapy. We demonstrated that LMW HA could be considered a new adjuvant candidate in the preparation of DC-based anticancer vaccines