Z-100, extracted from Mycobacterium tuberculosis strain Aoyama B, promotes TNF-α production via nucleotide-binding oligomerization domain containing 2 (Nod2)-dependent NF-κB activation in RAW264.7 cells.

Macrophages are a major component of the innate immune system, and the cytokines they secrete are involved in antitumor responses. Z-100 is obtained from hot-water extract of human-type Mycobacterium tuberculosis strain Aoyama B and activates the innate immune response. However, while Z-100 is known to modulate macrophage activity, the mechanism behind this modulation is not fully understood. We evaluated the effects of Z-100 on the murine macrophage cell line RAW264.7. Tumor necrosis factor-alpha (TNF-α) production from RAW264.7 cells was strongly induced by Z-100 and interferon-gamma (IFN-γ) stimulation but only weakly induced by Z-100 alone. Quantitative gene expression analysis showed that nucleotide-binding oligomerization domain containing 2 (Nod2) expression was up-regulated by IFN-γ treatment in RAW264.7 cells while Z-100-induced TNF-α production was attenuated by Nod2 gene silencing. Further, componential analysis demonstrated that muramic acid and amino acids distinctive of muramyl dipeptide (MDP) were contained within Z-100 and Z-100Fr I, the low-molecular-weight fraction containing components <3 kDa in size. In addition, Z-100Fr I enhanced TNF-α production in RAW264.7 cells and promoted NOD2-dependent nuclear factor-kappa B (NF-κB) activation in murine NOD2-expressing SEAP reporter HEK293 (HEK-Blue-mNOD2) cells. Taken together, these results suggest that Z-100 contains MDP-like molecules and augments NF-κB signaling via the direct activation of Nod2 in macrophages, which might be one mechanism driving the innate immune responses induced by Z-100 in cancer immunotherapy.

Phase III placebo-controlled double-blind randomized trial of radiotherapy for stage IIB-IVA cervical cancer with or without immunomodulator Z-100: a JGOG study.

BACKGROUND: Based on the result of our previous study showing better overall survival (OS) at the lower dose (0.2 µg) of immunomodulator Z-100 than higher dose (40 µg) in patients with locally advanced cervical cancer who received radiotherapy, we conducted a placebo-controlled double-blind randomized trial. PATIENTS AND METHODS: Patients of stages IIB-IVA squamous cell carcinoma of the uterine cervix were randomly assigned to receive Z-100 at 0.2 µg (Z) or placebo (P). The study agent was given subcutaneously twice a week during the radiotherapy, followed by maintenance therapy by administering once every 2 weeks until disease progression. Primary end point was OS, and secondary end points were recurrence-free survival, and toxicity. RESULTS: A total of 249 patients were randomized. Death events occurred extremely slower than expected, and Independent Data Monitoring Committee recommended to analyze the survival result prematurely. The 5-year OS rate was 75.7% [95% confidence interval (CI) 66.4% to 82.8%] for Arm Z and 65.8% (95% CI 56.2% to 73.8%) for Arm P (P = 0.07); hazard ratio was 0.65 (95% CI 0.40-1.04). Survival benefit in Arm Z was observed regardless of chemoradiation or radiation alone. There was no trend in recurrence-free survival between the two arms. Side-effects were not different between two arms. CONCLUSION: Z-100 showed a trend of improvement on OS in locally advanced cervical cancer, although the statistical power was less than anticipated because survival rates were unexpectedly higher than expected for both arms. Validation of potential survival benefit of immune modulation should be made. TRIAL REGISTRATION: umin.ac.jp/ctr Identifier: C000000221.