A research team led by Professor Eijiro Miyako at the Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology (JAIST), has discovered that the marine bacterium Photobacterium angustum demonstrates remarkable therapeutic efficacy against colorectal cancer.
Through screening of multiple marine bacterial strains, the researchers found that P. angustum, in its natural, non-engineered form, selectively accumulates in tumor tissues and induces both direct tumor lysis and robust immune activation. In mouse models, intravenously administered P. angustum showed high tumor tropism while exhibiting minimal colonization of vital organs except the liver, with no hematological abnormalities or histological toxicity observed.
Furthermore, P. angustum therapy promoted intratumoral infiltration of immune cells including T cells, B cells, and neutrophils, and enhanced production of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). The bacterium also demonstrated intrinsic oncolytic activity through natural exotoxin production, directly destroying cancer cells. These combined mechanisms significantly prolonged survival in treated mice, with complete remission achieved in some cases.
This research represents a critical advance toward developing safer, more biocompatible cancer immunotherapies that do not rely on genetically modified organisms (GMOs).
The study has been accepted for publication in the Journal for ImmunoTherapy of Cancer, a leading international journal in the field of cancer immunotherapy.
