The combination of microwave hyperthermia with TIPE2 impedes the growth of orthotopic colon cancer.

Background: Colon cancer (CC) is the main fatal disease of humans. Microwave hyperthermia (MH) is an adjuvant therapy for diverse cancers. Tumor necrosis factor-α induced protein-8-like 2 (TIPE2) is a tumor suppressor. However, the effect of MH combined with TIPE2 on CC remains unclear.

Methods: The orthotopic CC mouse model was constructed by mouse CC CT26-Luc cells, and mice were randomized into control, model (CT26-Luc), CT26-Luc + Vector, CT26-Luc + TIPE2, CT26-Luc + MH, and CT26-Luc + MH+TIPE2 groups (n = 6). Tumor growth pretreatment and post-treatment by in vivo fluorescence image analysis was detected. TIPE2 expression and cell transfection efficiency was detected by qRT-PCR and western blot. The pathological changes by HE staining, apoptosis by TUNEL staining, serum inflammatory factors by ELISA, TIPE2 expression by immunohistochemistry, and NF-κB signaling by western blot was performed.

Results: Paracancerous tissues showed higher TIPE2 expression than in CC tissues. CT26-Luc + TIPE2, CT26-Luc + MH, and CT26-Luc + MH+TIPE2 groups reduced tumor growth, tumor cell infiltration, and increased apoptosis. CT26-Luc + TIPE2 group had lower NF-κB, TNF-α, IL-1β, IL-6, p-p65, and p-IKK expression, and elevated TIPE2 and IkB expression, which was reversed by CT26-Luc + MH group. Moreover, CT26-Luc+MH+TIPE2 group showed opposite effects on the above factor expression of CT26-Luc+MH group.

Conclusions: Combination of MH with TIPE2 could impede CC tumor growth, providing scientific bases for its clinical application in CC treatment.