Abstract 2586: Therapeutic potential of the topical treatment of miR-634 ointment for cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most common nonmelanoma skin cancers. Surgery represents the gold standard for CSCC treatment, however it is needed to develop the noninvasive and effective treatments as the nonsurgical options for CSCC patients whose conditions are not suitable for or who refuse operation. On the other hand, microRNAs (miRs) are endogenous small non-coding RNAs negatively regulate gene expression by interfering with the translation or stability of target transcripts. Some tumor-suppressive miRs can target multiple cancer-promoting genes concurrently and may be useful as a therapeutic agent for cancer therapy. We have previously found that overexpression of miR-634 activated the mitochondrial apoptotic pathway by directly targeting genes associated with cytoprotective processes, including mitochondrial homeostasis, anti-apoptosis, antioxidant ability, and autophagy, in various cancer cells. The development of drug delivery system (DDS) is critical for the implementation of miR-based therapeutics. While topical pharmacotherapy represents a nonsurgical option to consider in CSCC, we validated the therapeutic potential of topical treatment of miR-634 ointment in mice model of CSCC. In xenograft tumors of A431 cells, a human epidermoid carcinoma cell line, in mice the topical treatment of ointment incorporated double-strand miR-634 mimics significantly reduced tumor growth. Furthermore, the topical treatment of miR-634-ointment also inhibited tumor growth in carcinogen-induced mouse skin papilloma model. Taken together, these findings suggest that topical treatment of miR-634-ointment may be useful as a noninvasive and effective treatments for CSCC. Citation Format: Jun Inoue, Kentaro Gokita, Masahiro Kishikawa, Hidetoshi Hamamoto, Katsunori Kobayashi, Kyoko Fujiwara, Takahiro Asakage, Kazuyuki Kojima, Johji Inazawa. Therapeutic potential of the topical treatment of miR-634 ointment for cutaneous squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2586.