Award type：Award from international society, conference, symposium, etc.  Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Oral Biosciences  

Objectives: Oral squamous cell carcinoma (OSCC), the most frequent cancer of the oral cavity, mostly arises from the mucosal epithelium and rarely from the odontogenic epithelium. However, it is unclear whether they share the same mechanisms of OSCC development. Recently, we clarified comprehensive gene expression patterns in pathological specimens of two types of OSCC (odontogenic epithelial and mucosal epithelial origin). In addition, the enrichment analysis demonstrated that the “COMPLEMENT” gene set was elevated in these tumor lesions. However, the role of this system in OSCC tumorigenesis remains unclear. Here, we aimed to investigate the involvement of complement components in OSCC development. Methods: siRNA and shRNA were used to examine OSCC cell proliferation in vitro and in vivo and assess activation of intracellular signaling using western blotting technics. An MEK1/2-specific inhibitor was used to verify its effects on the expression of C1r and/or C1s, components of the classical complement pathway. C1s expression in OSCC pathological specimens was investigated using immunohistochemical analysis. Results: C1r and/or C1s expression regulated ERK and/or AKT activation and promoted OSCC cell growth. In addition, activated ERK regulated the expression of C1r and C1s via a negative-feedback loop. Immunohistochemically, C1s was expressed in the tumor lesions and frequently showed high expression levels of both phosphorylated ERK and Ki-67, but not in the non-tumor regions of OSCC specimens. Conclusions: The complement system may be a common molecular mechanism for OSCC tumorigenesis, which arises from different origins: odontogenic and mucosal epithelium. Elevated C1r/C1s expression contributes to OSCC cell proliferation.

DOI： 10.1016/j.job.2025.100691

Web of Science

Scopus

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biochemical and Biophysical Research Communications  

Murine tooth germ development proceeds in continuous sequential steps with reciprocal interactions between the odontogenic epithelium and the adjacent mesenchyme, and several growth factor signaling pathways and their activation are required for tooth germ development. The expression of ADP-ribosylation factor (Arf)-like 4c (Arl4c) has been shown to induce cell proliferation, and is thereby involved in epithelial morphogenesis and tumorigenesis. In contrast, the other functions of Arl4c (in addition to cellular growth) are largely unknown. Although we recently demonstrated the involvement of the upregulated expression of Arl4c in the proliferation of ameloblastomas, which have the same origin as odontogenic epithelium, its effect on tooth germ development remains unclear. In the present study, single-cell RNA sequencing (scRNA-seq) analysis revealed that the expression of Arl4c, among 17 members of the Arf-family, was specifically detected in odontogenic epithelial cells, such as those of the stratum intermedium, stellate reticulum and outer enamel epithelium, of postnatal day 1 (P1) mouse molars. scRNA-seq analysis also demonstrated the higher expression of Arl4c in non-ameloblast and inner enamel epithelium, which include immature cells, of P7 mouse incisors. In the mouse tooth germ rudiment culture, treatment with SecinH3 (an inhibitor of the ARNO/Arf6 pathway) reduced the size, width and cusp height of the tooth germ and the thickness of the eosinophilic layer, which would involve the synthesis of dentin and enamel matrix organization. In addition, loss-of-function experiments using siRNAs and shRNA revealed that the expression of Arl4c was involved in cell proliferation and osteoblastic cytodifferentiation in odontogenic epithelial cells. Finally, RNA-seq analysis with a gene set enrichment analysis (GSEA) and Gene Ontology (GO) analysis showed that osteoblastic differentiation-related gene sets and/or GO terms were downregulated in shArl4c-expressing odontogenic epithelial cells. These results suggest that the Arl4c-ARNO/Arf6 pathway axis contributes to tooth germ development through osteoblastic/ameloblastic differentiation.

DOI： 10.1016/j.bbrc.2023.09.014

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Scopus

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Pathology Research and Practice  

Carcinogenesis is a multistep process wherein cells accumulate multiple genetic alterations and progress to a more malignant phenotype. It has been proposed that sequential accumulation of gene abnormalities in specific genes drives the transition from non-tumorous epithelia through a preneoplastic lesion/benign tumor to cancer. Histologically, oral squamous cell carcinoma (OSCC) progresses in multiple ordered steps that begin with mucosal epithelial cell hyperplasia, which is followed by dysplasia, carcinoma in situ and invasive carcinoma. It is therefore hypothesized that genetic alteration-mediated multistep carcinogenesis would be involved in the development of OSCC; however, the detailed molecular mechanisms are unknown. We clarified the comprehensive gene expression patterns and carried out an enrichment analysis using DNA microarray data from a pathological specimen of OSCC (including a non-tumor region, carcinoma in situ lesion and invasive carcinoma lesion). The expression of numerous genes and signal activation were altered in the development of OSCC. Among these, the p63 expression was increased and the MEK/ERK-MAPK pathway was activated in carcinoma in situ lesion and in invasive carcinoma lesion. Immunohistochemical analyses revealed that p63 was initially upregulated in carcinoma in situ and ERK was sequentially activated in invasive carcinoma lesions in OSCC specimens. ADP-ribosylation factor (ARF)-like 4c (ARL4C), the expression of which is reportedly induced by p63 and/or the MEK/ERK-MAPK pathway in OSCC cells, has been shown to promote tumorigenesis. Immunohistochemically, in OSCC specimens, ARL4C was more frequently detected in tumor lesions, especially in invasive carcinoma lesions, than in carcinoma in situ lesions. Additionally, ARL4C and phosphorylated ERK were frequently merged in invasive carcinoma lesions. Loss-of-function experiments using inhibitors and siRNAs revealed that p63 and MEK/ERK-MAPK cooperatively induce the expression of ARL4C and cell growth in OSCC cells. These results suggest that the stepwise activation of p63 and MEK/ERK-MAPK contributes to OSCC tumor cell growth through regulation of ARL4C expression.

DOI： 10.1016/j.prp.2023.154493

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Scopus

PubMed

Event date： 2026.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka  

Event date： 2026.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Hokkaido   Country：Japan  

Event date： 2026.3

Language：English   Presentation type：Poster presentation  

Venue：Munich   Country：Germany  

Event date： 2025.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Event date： 2025.11

Language：English   Presentation type：Poster presentation  

Venue：Fukuoka   Country：Japan