Characterization of a Novel Murine Colon Carcinoma Subline with High-Metastatic Activity Established by In Vivo Selection Method

Establishment of highly metastatic ovarian cancer model with omental tropism via in vivo selection

Epithelial ovarian cancer (OC) is often diagnosed at an advanced stage with peritoneal metastasis, and preclinical models mimicking the natural course of OC peritoneal metastasis are essential to improve treatment. We implanted ES2 and ID8 cells in the ovaries of mice and obtained highly metastatic (HM) sublines from their omental metastases after three cycles in vivo selection. Orthotopic xenografts derived from the HM sublines showed enhanced omental tropism and more extensive metastasis with earlier onset. The HM cells exhibited increased in vitro migration and invasion properties, and RNA sequencing revealed that the genes related to epithelial-mesenchymal transition and extracellular matrix regulation were significantly altered in the HM cells. Among them, the upregulated genes were significantly associated with poorer survival in OC patients. In conclusion, these HM sublines can be leveraged to establish spontaneous metastatic OC mouse models, which may serve as ideal preclinical models for anti-metastasis therapy for OC patients.

From Photon Beam to Accelerated Particle Beam: Antimetastasis Effect of Combining Radiotherapy With Immunotherapy

Cancer is one of the major diseases that seriously threaten the human health. Radiotherapy is a common treatment for cancer. It is noninvasive and retains the functions of the organ where the tumor is located. Radiotherapy includes photon beam radiotherapy, which uses X-rays or gamma rays, and particle beam radiotherapy, using beams of protons and heavy ions. Compared with photon beam radiotherapy, particle beam radiotherapy has excellent dose distribution, which enables it to kill the primary tumor cells more effectively and simultaneously minimize the radiation-induced damage to normal tissues and organs surrounding the tumor. Despite the excellent therapeutic effect of particle beam radiotherapy on the irradiated tumors, it is not an effective treatment for metastatic cancers. Therefore, developing novel and effective treatment strategies for cancer is urgently needed to save patients with distant cancer metastasis. Immunotherapy enhances the body's own immune system to fight cancer by activating the immune cells, and consequently, to achieve the systemic anticancer effects, and it is considered to be an adjuvant therapy that can enhance the efficacy of particle beam radiotherapy. This review highlights the research progress of the antimetastasis effect and the mechanism of the photon beam or particle beam radiotherapy combined with immunotherapy and predicts the development prospects of this research area.

Th balance related host genetic background affects the therapeutic effects of combining carbon-ion radiotherapy with dendritic cell immunotherapy

PURPOSE

The goal of this study is to clarify the underlying mechanisms of metastasis suppression by CiDC (carbon-ion radiotherapy (CIRT) combined with immature dendritic cell (iDC) immunotherapy), which was previously shown to significantly suppress pulmonary metastasis in a NR-S1-bearing C3H/He mouse model.

METHODS AND MATERIALS

Mouse carcinoma cell lines (LLC, LM8, Colon-26 and Colon-26MGS) were grafted into the right hind paw of syngeneic mice (C57BL/6J, C3H/He and BALB/c). Seven days later, the tumors on the mice were locally irradiated with carbon-ions (290 MeV/n, 6 cm SOBP, 1 or 2 Gy). At 1.5 days after irradiation, bone marrow-derived immature dendritic cells were administrated intravenously into a subset of the mice. The number of lung metastases was evaluated within three weeks after irradiation. In vitro cultured cancer cells were irradiated with carbon-ion (290 MeV/n, mono-energy, LET approximately 70 ∼ 80 keV/µm), and then co-cultured with iDCs for three days to determine the DC maturation.

RESULTS

CiDC effectively repressed distant lung metastases in cancer cell (LLC and LM8)-bearing C57BL/6J and C3H/He mouse models. However, Colon-26 and Colon-26MGS-bearing BALB/c models did not show enhancement of metastasis suppression by combination treatment. This was further evaluated by comparing LM8-bearing C3H/He and LLC-bearing C57BL/6J models with a Colon-26-bearing BALB/c model. In vitro co-culture assays demonstrated that all irradiated cell lines were able to activate C3H/He or C57BL/6J-derived iDCs into mature DCs, but not BALB/c-derived iDCs.

CONCLUSION

The genetic background of the host may have a strong impact on the potency of combination therapy. Future animal and clinical testing should evaluate host genetic factors when evaluating treatment efficacy.