GD2を標的とした近赤外線光免疫療法による高リスク神経芽細胞腫細胞へのアプローチ

Neuroblastoma (NB) is a primary malignant tumor of the peripheral sympathetic nervous system in infancy. Despite advances in treatment, the prognosis remains poor for high-risk NB patients. Although immunotherapy using anti-GD2 antibodies is available for high-risk NB, the therapeutic efficacy is insufficient. Near-infrared photoimmunotherapy (NIR-PIT) is an antitumor strategy that induces tumor-specific cytotoxicity by combining an antibody-photoabsorber conjugate (APC) with NIR light irradiation. In this study, we investigated the therapeutic efficacy of GD2-targeted NIR-PIT against human NB cells.

GD2 expression was analyzed on the surface of high-risk human NB cells (CHP-134, LA-N-5, IMR-32) and non-high-risk human NB cells (SK-N-SH) by flow cytometry. The APC was synthesized by incubating anti-GD2 antibody and IR700. The cytotoxic effect of GD2-targeted NIR-PIT was evaluated using the XTT assay. The distribution of dead cells within tumor spheres was evaluated using a live/dead assay. The in vivo antitumor effect of GD2-targeted NIR-PIT was assessed using a subcutaneous human NB xenograft tumor model.

GD2 protein was expressed on the surface of CHP-134, LA-N-5, and IMR-32 cells but not SK-N-SH cells. GD2-targeted NIR-PIT significantly suppressed the viability of GD2-positive NB cells but not GD2-negative NB cells, compared to the control and monotherapy groups. GD2-targeted NIR-PIT significantly reduced the volume of GD2-positive CHP-134 tumor spheres by inducing the accumulation of dead cells. Subcutaneous CHP-134 xenograft tumor models demonstrated that GD2-targeted NIR-PIT significantly inhibited tumor growth compared with the control and monotherapy groups.

GD2-targeted NIR-PIT is a promising antitumor strategy for treating high-risk NB tumors expressing GD2.