1Department of Diagnostic and Biomedical Sciences, University of Texas Health Sciences Center at Houston School of Dentistry, 7500 Cambridge Street, Houston, TX 77054 USA.
2Department of Oral Pathology and Medicine, School of Dentistry, University of Athens, Athens, Greece.
Cell Mol Biol Lett. 2018 Jul 11;23:30. doi: 10.1186/s11658-018-0096-y. eCollection 2018.
Recent findings indicate that dentin sialophosphoprotein (DSPP) and matrix metalloproteinase (MMP) 20 interact in oral squamous cell carcinoma (OSCC). The objective of this study was to determine the effects of DSPP/MMP20 gene silencing on oral cancer stem cell (OCSC) markers.
The expression of well-established OCSC markers: ABCG2; ALDH1; CD133; CD44; BMI1; LGR4, and Podoplanin in DSPP/MMP20-silenced OSCC cell line, OSC2, and controls were assayed by western blot (WB), and flow cytometry techniques. The sensitivity of OSC2 cells to cisplatin following DSPP/MMP20 silencing was also determined.
DSPP/MMP20 silencing resulted in downregulation of OCSC markers, more profoundly ABCG2 (84%) and CD44 (81%), following double silencing. Furthermore, while treatment of parent (pre-silenced) OSC2 cells with cisplatin resulted in upregulation of OCSC markers, DSPP/MMP20-silenced OSC2 cells similarly treated resulted in profound downregulation of OCSC markers (72 to 94% at 50 μM of cisplatin), and a marked reduction in the proportion of ABCG2 and ALDH1 positive cells (~ 1%).
We conclude that the downregulation of OCSC markers may signal a reduction in OCSC population following MMP20/DSPP silencing in OSCC cells, while also increasing their sensitivity to cisplatin. Thus, our findings suggest a potential role for DSPP and MMP20 in sustaining OCSC population in OSCCs, possibly, through mechanism(s) that alter OCSC sensitivity to treatment with chemotherapeutic agents such as cisplatin.
最近的研究结果表明，牙本质涎磷蛋白（DSPP）和基质金属蛋白酶 20（MMP20）在口腔鳞状细胞癌（OSCC）中相互作用。本研究的目的是确定 DSPP/MMP20 基因沉默对口腔癌干细胞（OCSC）标志物的影响。
通过 Western blot（WB）和流式细胞术技术检测 DSPP/MMP20 沉默的 OSCC 细胞系 OSC2 和对照中已建立的 OCSC 标志物的表达：ABCG2；ALDH1；CD133；CD44；BMI1；LGR4 和 Podoplanin。还测定了 DSPP/MMP20 沉默后 OSC2 细胞对顺铂的敏感性。
DSPP/MMP20 沉默导致 OCSC 标志物的下调，双重沉默后 ABCG2（84%）和 CD44（81%）下调更为明显。此外，虽然用顺铂处理亲本（预沉默）OSC2 细胞会导致 OCSC 标志物上调，但同样用 DSPP/MMP20 沉默的 OSC2 细胞处理会导致 OCSC 标志物明显下调（50 μM 顺铂时下调 72%至 94%），ABCG2 和 ALDH1 阳性细胞的比例也明显降低（~1%）。
我们得出结论，DSPP/MMP20 沉默后 OCSC 标志物的下调可能表明 OSCC 细胞中 OCSC 群体减少，同时增加其对顺铂的敏感性。因此，我们的研究结果表明，DSPP 和 MMP20 可能通过改变 OCSC 对顺铂等化疗药物的敏感性的机制，在维持 OSCC 中的 OCSC 群体中发挥作用。
