RESUMO
BACKGROUND: Despite the majority of patients do not gain any benefit from dendritic cells (DC) vaccines, this approach has occasionally given rise to dramatic responses in melanoma. Biomarkers are crucial to identify which patients are more likely to respond. We looked for correlations between pre- or post- vaccination biomarkers and clinical outcomes to DC therapy in a cohort of patients with stage IV melanoma receiving a vaccine with autologous ex-vivo expanded DCs pulsed with allogeneic tumor cell lysate. METHODS: Serial serum samples were collected at baseline, week 4 and 12 and they were analyzed for a panel of different inflammatory markers using cytometric bead array technology and ELISA. RESULTS: Twenty-one patients were evaluable for response. Patients were separated into responders and non-responders based on clinical benefit. Responders were defined as patients who achieved a complete response, partial response or stable disease the latter lasting for at least 6 months. Responders (N = 9) showed a significantly longer Progression-free Survival (PFS; HR 0.23; 95% CI 0.08-062; P < .001) and Overall Survival (OS; HR 0.22; 95% CI 0.08-0.59; P < .001). The clinical non-responder phenotype correlated with an elevated pre-vaccination level of cytokines associated with inflammation compared to clinical responders (Apolipoprotein C111; IL-12 p40; MiP1α; Stem Cell Factor and TNFα). Apolipoprotein E (ApoE) was also significantly elevated in the pre-vaccine sera of the clinically non-responding group and in addition it was found to correlate with outcomes. Patients with increased levels of ApoE had a significantly shorter PFS (HR 3.02; 95% CI 1.09-8.35; P = .015) and OS (HR 2.40; 95% CI 0.9-6.3; P = .034). CONCLUSION: Our findings support the notion that treating the inflammatory background may have an impact on clinical outcome for patients receiving immunotherapy. A larger study is needed to confirm the significance of ApoE as a predictive biomarker for response to DC vaccines.
RESUMO
It has been reported that lower doses of the opioid antagonist naltrexone are able to reduce tumour growth by interfering with cell signalling as well as by modifying the immune system. We have evaluated the gene expression profile of a cancer cell line after treatment with low-dose naltrexone (LDN), and assessed the effect that adapting treatment schedules with LDN may have on enhancing efficacy. LDN had a selective impact on genes involved with cell cycle regulation and immune modulation. Similarly, the pro-apoptotic genes BAD and BIK1 were increased only after LDN. Continuous treatment with LDN had little effect on growth in different cell lines; however, altering the treatment schedule to include a phase of culture in the absence of drug following an initial round of LDN treatment, resulted in enhanced cell killing. Furthermore, cells pre-treated with LDN were more sensitive to the cytotoxic effects of a number of common chemotherapy agents. For example, priming HCT116 with LDN before treatment with oxaliplatin significantly increased cell killing to 49±7.0 vs. 14±2.4% in cultures where priming was not used. Interestingly, priming with NTX before oxaliplatin resulted in just 32±1.8% cell killing. Our data support further the idea that LDN possesses anticancer activity, which can be improved by modifying the treatment schedule.
