[Comparison of T cell response in the tumor milieu of patients with HPV+ and HPV- head and neck cancer]

Low postoperative lymphocyte count increases risk of progression in human papillomavirus associated oropharyngeal cancer

BACKGROUND

We aim to explore the prognostic role of absolute lymphocyte count (ALC) before, during, and after treatment on oncologic outcomes in human papillomavirus associated oropharyngeal cancer (HPV(+)OPSCC).

METHODS

Retrospective cohort at a tertiary center, 2006-2018. Multivariable Cox regressions were used to determine the effect of ALC on risk of progression. Univariate linear regression was performed to determine clinical factors associated with lower ALC.

RESULTS

All 197 patients underwent primary surgery. Mean (SD) ALC nadirs (×10⁹  cells/L) were: baseline (N = 149): 1.69 (0.56); postoperative (N = 126): 1.58 (0.59); post-RT (N = 141): 0.68 (0.35) and long-term (N = 105): 0.88 (0.37). Lower baseline ALC nadir was associated with worse overall survival (HR 3.85, 95%CI: 1.03-14.29, p = 0.04). Lower postoperative ALC nadir was associated with higher risk of progression (HR 2.63, 95%CI: 1.04-6.67, p = 0.04).

CONCLUSIONS

Lower baseline ALC is associated with worse survival, whereas lower postoperative ALC is associated with increased risk of progression in surgically treated HPV(+)OPSCC.

LEVEL OF EVIDENCE: 3

Black raspberry extract inhibits regulatory T-cell activity in a murine model of head and neck squamous cell carcinoma chemoprevention

Head and neck squamous cell carcinomas (HNSCC) are one of the most diagnosed malignancies globally, with a 5-year survival rate of approximately 40% to 50%. Current therapies are limited to highly invasive surgery, aggressive radiation, and chemotherapies. Recent reports have demonstrated the potential phytochemical properties of black raspberries in inhibiting the progression of various cancers including HNSCCs. However, the effects of black raspberry extracts on immune cells of the tumor microenvironment, specifically regulatory T cells during HNSCC, have not been investigated. We used a mouse model of 4-nitroquinoline-1-oxide (4NQO) chemically induced HNSCC carcinogenesis to determine these effects. C57BL/6 mice were exposed to 4NQO for 16 weeks and regular water for 8 weeks. 4NQO-exposed mice were fed the AIN-76A control mouse diet or the AIN76 diet supplemented with black raspberry extract. At terminal sacrifice, tumor burdens and immune cell recruitment and activity were analyzed in the tumor microenvironment, draining lymph nodes, and spleens. Mice fed the BRB extract-supplemented diet displayed decreased tumor burden compared to mice provided the AIN-76A control diet. Black raspberry extract administration did not affect overall T-cell populations as well as Th1, Th2, or Th17 differentiation in spleens and tumor draining lymph nodes. However, dietary black raspberry extract administration inhibited regulatory T-cell recruitment to HNSCC tumor sites. This was associated with an increased cytotoxic immune response in the tumor microenvironment characterized by increased CD8⁺ T cells and enhanced Granzyme B production during BRB extract-mediated HNSCC chemoprevention. Interestingly, this enhanced CD8⁺ T-cell antitumoral response was localized at the tumor sites but not at spleens and draining lymph nodes. Furthermore, we found decreased levels of PD-L1 expression by myeloid populations in draining lymph nodes of black raspberry-administered carcinogen-induced mice. Taken together, our findings demonstrate that black raspberry extract inhibits regulatory T-cell recruitment and promotes cytotoxic CD8 T-cell activity at tumor sites during HNSCC chemoprevention. These results demonstrate the immunomodulatory potential of black raspberry extracts and support the use of black raspberry-derived phytochemicals as a complementary approach to HNSCC chemoprevention and treatment.

Development and Characterization of a Novel Non-Lytic Cancer Immunotherapy Using a Recombinant Arenavirus Vector Platform

Engineered viral vectors represent a promising strategy to trigger antigen-specific antitumor T cell responses. Arenaviruses have been widely studied because of their ability to elicit potent and protective T cell responses. Here, we provide an overview of a novel intravenously administered, replication-competent, non-lytic arenavirus-based vector technology that delivers tumor antigens to induce antigen-specific anti-cancer T cell responses. Preclinical studies in mice and cell culture experiments with human peripheral blood mononuclear cells demonstrate that arenavirus vectors preferentially infect antigen-presenting cells. This, in conjunction with a non-lytic functional activation of the infected antigen-presenting cells, leads to a robust antigen-specific CD8⁺ T cell response. T cell migration to, and infiltration of, the tumor microenvironment has been demonstrated in various preclinical tumor models with vectors encoding self- and non-self-antigens. The available data also suggest that arenavirus-based vector therapy can induce immunological memory protecting from tumor rechallenge. Based on promising preclinical data, a phase 1/2 clinical trial was initiated and is currently ongoing to test the activity and safety of arenavirus vectors, HB-201 and HB-202, created using lymphocytic choriomeningitis virus and Pichinde virus, respectively. Both vectors have been engineered to deliver non-oncogenic versions of the human papilloma virus 16 (HPV16) antigens E7 and E6 and will be injected intravenously with or without an initial intratumoral dose. This dose escalation/expansion study is being conducted in patients with recurrent or metastatic HPV16+ cancers. Promising preliminary data from this ongoing clinical study have been reported. Immunogenicity data from several patients demonstrate that a single injection of HB-201 or HB-202 monotherapy is highly immunogenic, as evidenced by an increase in inflammatory cytokines/chemokines and the expansion of antigen-specific CD8⁺ T cell responses. This response can be further enhanced by alternating injections of HB-202 and HB-201, which has resulted in frequencies of circulating HPV16 E7/E6-specific CD8⁺ T cells of up to 40% of the total CD8⁺ T cell compartment in peripheral blood in analyses to date. Treatment with intravenous administration also resulted in a disease control rate of 73% among 11 evaluable patients with head and neck cancer dosed every three weeks, including 2 patients with a partial response.