Recent immunotherapy treatments are showing promising results in cancer management, but a proportion of patients do not fully benefit from therapy and fail to achieve durable responses or experience relapse.Chimeric antigen receptor (CAR) vector insertion at epigenetic chromosomal sites may determine the potency and durability of CAR-T cell cytotoxic responses, as shown for the complete remission of a chronic lymphocytic leukemia (CLL) patient with TET2 disruption caused by CAR19 vector integration.Novel biomarkers of response are needed, and epigenetic biomarkers may represent solid candidates for filling this niche, thereby contributing to theragnosis and precision medicine.Combinatorial approaches of epigenetic drugs with immunotherapy may synergize to reshape the tumor microenvironment and restore an effective antitumor response, thus overcoming immunotherapy limitations for some cancer types.

Immune checkpoint inhibitors are currently tested in different combinations in patients with advanced hepatocellular carcinoma (HCC). Nivolumab, an anti-PD-1 agent, has gained approval in the second-line setting in the USA. Epigenetic drugs have immune-mediated antitumor effects that may improve the activity of immunotherapy agents. Our aim was to study the therapeutic efficacy of checkpoint inhibitors (anti-CTLA-4 and anti-PD-1 antibodies) in combination with the histone deacetylase inhibitor (HDACi) Belinostat. In a subcutaneous Hepa129 murine HCC model, we demonstrated that Belinostat improves the antitumor activity of anti-CTLA-4 but not of anti-PD-1 therapy. This effect correlated with enhanced IFN-γ production by antitumor T-cells and a decrease in regulatory T-cells. Moreover, the combination induced early upregulation of PD-L1 on tumor antigen-presenting cells and late expression of PD-1 on tumor-infiltrating effector T-cells, suggesting the suitability of PD-1 blockade. Indeed, Belinostat combined with the simultaneous blockade of CTLA-4 and PD-1 led to complete tumor rejection. These results provide a rationale for testing Belinostat in combination with checkpoint inhibitors to enhance their therapeutic activity in patients with HCC.

Regulatory T cell (Treg) activity is modulated by a cooperative complex between the transcription factor NFAT and FOXP3, a lineage specification factor for Tregs. FOXP3/NFAT interaction is required to repress expression of IL-2, upregulate expression of the Treg markers CTLA4 and CD25, and confer suppressor function to Tregs. However, FOXP3 is expressed transiently in conventional CD4+ T cells upon TCR stimulation and may lead to T cell hyporesponsiveness. We found that a short synthetic peptide able to inhibit FOXP3/NFAT interaction impaired suppressor activity of conventional Tregs in vitro. Specific inhibition of FOXP3/NFAT interaction with this inhibitory peptide revealed that FOXP3 downregulates NFAT-driven promoter activity of CD40L and IL-17. Inhibition of FOXP3/NFAT interaction upregulated CD40L expression on effector T cells and enhanced T cell proliferation and IL-2, IFN-γ, IL-6, or IL-17 production in response to TCR stimulation. The inhibitory peptide impaired effector T cell conversion into induced Tregs in the presence of TGF-β. Moreover, in vivo peptide administration showed antitumor efficacy in mice bearing Hepa129 or TC1 tumor cells when combined with sorafenib or with an antitumor vaccine, respectively. Our results suggest that inhibition of NFAT/FOXP3 interaction might improve antitumor immunotherapies.

Vaccination induces immunostimulatory signals that are often accompanied by regulatory mechanisms such as IL-10, which control T-cell activation and inhibit vaccine-dependent antitumor therapeutic effect. Here we characterized IL-10-producing cells in different tumor models treated with therapeutic vaccines. Although several cell subsets produced IL-10 irrespective of treatment, an early vaccine-dependent induction of IL-10 was detected in dendritic cells (DC). IL-10 production defined a DC population characterized by a poorly mature phenotype, lower expression of T-cell stimulating molecules and upregulation of PD-L1. These IL-10+ DC showed impaired in vitro T-cell stimulatory capacity, which was rescued by incubation with IL-10R and PD-L1-inhibiting antibodies. In vivo IL-10 blockade during vaccination decreased the proportion of IL-10+ DC and improved their maturation, without modifying PD-L1 expression. Similarly, PD-L1 blockade did not affect IL- 10 expression. Interestingly, vaccination combined with simultaneous blockade of IL-10 and PD-L1 induced stronger immune responses, resulting in a higher therapeutic efficacy in tumor-bearing mice. These results show that vaccine-induced immunoregulatory IL- 10+ DC impair priming of antitumor immunity, suggesting that therapeutic vaccination protocols may benefit from combined targeting of inhibitory molecules expressed by this DC subset.

Cervical carcinoma is one of the most common cancers in women worldwide. It is well established that chronic infection of the genital tract by various mucosatropic human papillomavirus (HPV) types causes cervical cancer. Cellular immunity to E7 protein from HPV (HPVE7) has been associated with clinical and cytologic resolution of HPV-induced lesions. Thus, we decided to test if targeting of HPVE7 to dendritic cells using a fusion protein containing the extra domain A (EDA) from fibronectin, a natural ligand for TLR4, and HPVE7 (EDA-HPVE7) might be an efficient vaccine for the treatment of cervical carcinoma. We found that EDA-HPVE7 fusion protein was efficiently captured by bone marrow derived dendritic cells in vitro and induced their maturation, with the upregulation of maturation markers and the production of IL-12. Immunization of mice with EDA-HPVE7 fusion protein induced antitumor CD8 1 T cell responses in the absence of additional adjuvants. Repeated intratumoral administration of EDA-HPVE7 in saline was able to cure established TC-1 tumors of 5-7 mm in diameter. More importantly, intravenous injection with EDA-HPVE7 in combination with the TLR ligand polyinosinic-polycytidylic acid (pIC), or with low doses of cyclophosphamide and the TLR9 ligand CpG-B complexed in cationic lipids, were able to eradicate large established TC-1 tumors (1.2 cm in diameter). Thus, therapeutic vaccination with EDA-HPVE7 fusion protein may be effective in the treatment of human cervical carcinoma.There is consistent evidence that chronic infection of the genital tract by various mucosatropic human papillomavirus (HPV) types cause cervical cancer. 1 In contrast to the prophylactic HPV vaccines that exhibit great promise in reducing the burden of cervical cancer, there is limited progress towards the development of immune therapeutic strategies for those women already infected with HPV who do not benefit from the current vaccines. The efficacy of these HPV vaccines correlates with the presence of serum neutralizing antibodies which may prevent virus infection (reviewed in ref. 2). However, it is believed that T cell immune responses, in particular against E7 protein, may play an important role in viral clearance and resolution of HPV-induced lesions. 3 Thus, a vaccination strategy able to activate a strong T cell immune response with the capacity to recognize and kill cancer cells expressing HPV proteins might be considered as therapeutic alternative for cervical carcinoma.Dendritic cells (DCs) are considered to be at the centre of acquired T cell responses due to their outstanding ability to capture antigens (Ag) and process them for their presentation as short peptides in the context of MHC molecules to naïve T cells. The unique capacity of DC to elicit immune responses has prompted many laboratories to use DC in clinical trials. However, ex vivo manipulation of DC for the production of DC-based vaccines is expensive, time consuming and difficult to standardize. Indeed, several variables, such as DC lineage, antigen loading to...

Background Chimeric antigen receptor (CAR) T-cells directed against CD19 (CART19) are effective in B-cell malignancies, but little is known about the molecular factors predicting clinical outcome of CART19 therapy. The increasingly recognized relevance of epigenetic changes in cancer immunology prompted us to determine the impact of the DNA methylation profiles of CART19 cells on the clinical course. Methods We recruited 114 patients with B-cell malignancies, comprising 77 acute lymphoblastic leukemia (ALL) and 37 non-Hodgkin lymphoma (NHL) patients, who were treated with CART19 cells. Using a comprehensive DNA methylation microarray, we determined the epigenomic changes that occur in the patient T-cells upon transduction of the CAR vector. The effects of the identified DNA methylation sites on clinical response, cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), event-free survival (EFS) and overall survival (OS) were assessed. All statistical tests were 2-sided. Results We identified 984 genomic sites with differential DNA methylation between CAR-untransduced and CAR-transduced T-cells before infusion into the patient. Eighteen of these distinct epigenetic loci were associated with complete response (CR) adjusting by multiple testing. Using the sites linked to CR, the EPICART signature was established in the initial discovery cohort (n = 79), which was associated with CR (Fisher’s exact test, P<.001) and enhanced EFS (HR = 0.36, 95% CI = 0.19 to 0.70, P=.002; log-rank P=.003) and OS (HR = 0.45, 95% CI = 0.20 to 0.99, P=.047; log-rank P=.04;). Most important the EPICART profile maintained its clinical course predictive value in the validation cohort (n = 35) where it was associated with CR (Fisher’s exact test, P<.001) and enhanced OS (HR = 0.31, 95% CI = 0.11 to 0.84, P=.02; log-rank P=.02). Conclusions We show that the DNA methylation landscape of patient CART19 cells influences the efficacy of the cellular immunotherapy treatment in patients with B-cell malignancy.

Tumor infiltrating lymphocytes have been associated with a better prognostic and with higher response rates in patients treated with checkpoint inhibiting antibodies, suggesting that strategies promoting tumor inflammation may enhance the efficacy of these currently available therapies. Our aim was thus to develop a new vaccination platform based on cold-inducible RNA binding protein (CIRP), an endogenous TLR4 ligand generated during inflammatory processes, and characterize whether it was amenable to combination with checkpoint inhibitors. In vitro, CIRP induced dendritic cell activation, migration and enhanced presentation of CIRP-bound antigens to T-cells. Accordingly, antigen conjugation to CIRP conferred immunogenicity, dependent on immunostimulatory and antigen-targeting capacities of CIRP. When applied in a therapeutic setting, vaccination led to CD8-dependent tumor rejection in several tumor models. Moreover, immunogenicity of this vaccination platform was enhanced not only by combination with additional adjuvants, but also with antibodies blocking PD-1/PD-L1, CTLA-4 and IL-10, immunosuppressive molecules usually present in the tumor environment and also induced by the vaccine. Therefore, priming with a CIRP-based vaccine combined with immune checkpoint-inhibiting antibodies rejected established B16-OVA tumors. Finally, equivalent activation and T-cell stimulatory effects were observed when using CIRP in vitro with human cells, suggesting that CIRP-based vaccination strategies could be a valuable clinical tool to include in combinatorial immunotherapeutic strategies in cancer patients.

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