Sakinah-Syed Gulam, Liew Jia Shi, Abdul Majid Nazia, Inche Zainal Abidin Siti Amalina
Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur, WP Kuala Lumpur, Malaysia.
Department of Oral & Craniofacial Sciences, Faculty of Dentistry, Universiti Malaya, Kuala Lumpur, WP Kuala Lumpur, Malaysia.
PeerJ. 2025 Feb 24;13:e18931. doi: 10.7717/peerj.18931. eCollection 2025.
Aberrations in primary cilia expression and intraflagellar transport (IFT) protein function have been implicated in tumourigenesis. This study explores the relationship between the alteration of primary cilia and tumourigenesis by investigating primary cilia expression and the role of IFT20 in regulating matrix metalloproteinase 9 (MMP-9) expression in oral squamous cell carcinoma (OSCC) cell lines.
The frequency and length of primary cilia were determined in OKF6-TERT2 cells, HSC-2 cells, and HSC-3 cells using immunofluorescence. Additionally, primary cilia presence in non-proliferating OSCC cells was examined. OSCC cells were treated with either small interfering RNA (siRNA) negative control or siRNA targeting IFT20 for functional analysis. mRNA expression levels of IFT20 and MMP-9 were quantified using quantitative reverse transcription polymerase chain reaction (qRT-PCR).
Results showed that HSC-2 cells exhibit abundant primary cilia when cultured in low serum media (2% serum) for 48 h, followed by serum starvation for over 72 h. No significant changes in cilia expression were observed in HSC-3 cells compared to OKF6-TERT2 cells. Ciliated cells were found in non-proliferating HSC-2 and HSC-3 cells. OSCC cells showed longer cilia than OKF6-TERT2 cells, indicating ciliary abnormalities. Changes in ciliation and cilium length of OSCC cells were accompanied by increased expression of IFT20, an intraflagellar transport protein crucial for the primary cilia assembly. However, IFT20 knockdown did not affect MMP-9 at the mRNA level in these cells.
This study reveals the differences in primary cilia expression among OSCC cells. Furthermore, the increased abundance and elongation of primary cilia in OSCC cells are accompanied by elevated expression of IFT20. Nonetheless, IFT20 did not affect MMP-9 mRNA expression in OSCC cells.
原发性纤毛表达和鞭毛内运输（IFT）蛋白功能异常与肿瘤发生有关。本研究通过调查原发性纤毛表达以及IFT20在调节口腔鳞状细胞癌（OSCC）细胞系中基质金属蛋白酶9（MMP-9）表达方面的作用，探讨原发性纤毛改变与肿瘤发生之间的关系。
使用免疫荧光法测定OKF6-TERT2细胞、HSC-2细胞和HSC-3细胞中原发性纤毛的频率和长度。此外，检查了非增殖性OSCC细胞中是否存在原发性纤毛。用小干扰RNA（siRNA）阴性对照或靶向IFT20的siRNA处理OSCC细胞进行功能分析。使用定量逆转录聚合酶链反应（qRT-PCR）定量IFT20和MMP-9的mRNA表达水平。
结果显示，HSC-2细胞在低血清培养基（2%血清）中培养48小时，然后血清饥饿72小时以上时，表现出丰富的原发性纤毛。与OKF6-TERT2细胞相比，HSC-3细胞中纤毛表达无显著变化。在非增殖性HSC-2和HSC-3细胞中发现了有纤毛的细胞。OSCC细胞的纤毛比OKF6-TERT2细胞长，表明存在纤毛异常。OSCC细胞纤毛形成和纤毛长度的变化伴随着IFT20表达的增加，IFT蛋白对原发性纤毛组装至关重要。然而，在这些细胞中，IFT20基因敲低在mRNA水平上不影响MMP-9。
本研究揭示了OSCC细胞中原发性纤毛表达的差异。此外，OSCC细胞中原发性纤毛丰度增加和伸长伴随着IFT20表达的升高。尽管如此，IFT20在OSCC细胞中不影响MMP-9 mRNA表达。
