Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Nov 24;21(23):8897.
doi: 10.3390/ijms21238897.

Increased FOXM1 Expression by Cisplatin Inhibits Paclitaxel-Related Apoptosis in Cisplatin-Resistant Human Oral Squamous Cell Carcinoma (OSCC) Cell Lines

Hyeong Sim Choi  1 , Young-Kyun Kim  1   2 , Kyung-Gyun Hwang  3 , Pil-Young Yun  1
Affiliations

Increased FOXM1 Expression by Cisplatin Inhibits Paclitaxel-Related Apoptosis in Cisplatin-Resistant Human Oral Squamous Cell Carcinoma (OSCC) Cell Lines

Hyeong Sim Choi et al. Int J Mol Sci. .

Abstract

Cisplatin and paclitaxel are commonly used to treat oral cancer, but their use is often limited because of acquired drug resistance. Here, we tested the effects of combined cisplatin and paclitaxel on three parental (YD-8, YD-9, and YD-38) and three cisplatin-resistant (YD-8/CIS, YD-9/CIS, and YD-38/CIS) oral squamous cell carcinoma (OSCC) cell lines using cell proliferation assays and combination index analysis. We detected forkhead box protein M1 (FOXM1) mRNA and protein expression via real-time qPCR and Western blot assays. Cell death of the cisplatin-resistant cell lines in response to these drugs with or without a FOXM1 inhibitor (forkhead domain inhibitory compound 6) was then measured by propidium iodide staining and TdT dUTP nick end labeling (TUNEL) assays. In all six OSCC cell lines, cell growth was more inhibited by paclitaxel alone than combination therapy. Cisplatin-induced overexpression of FOXM1 showed the same trend only in cisplatin-resistant cell lines, indicating that it was associated with inhibition of paclitaxel-related apoptosis. In summary, these results suggest that, in three cisplatin-resistant cell lines, the combination of cisplatin and paclitaxel had an antagonistic effect, likely because cisplatin blocks paclitaxel-induced apoptosis. Cisplatin-induced FOXM1 overexpression may explain the failure of this combination.

Keywords: FOXM1; OSCC; apoptosis; cisplatin; paclitaxel.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest related to this work.

Figures

Figure 1
Figure 1
Cisplatin and paclitaxel used in combination had no synergistic effect in oral squamous cell carcinoma (OSCC) cancer cell lines. (A,B) Cells were treated with cisplatin (0–10 μg/mL) or paclitaxel (0–0.1 μg/mL) for 24 and 48 h. After 24 h, cell growth of these cancer cell lines was more inhibited by paclitaxel (0.1 μg/mL) alone than by cisplatin (10 μg/mL) alone or by combined treatment. The effect of cisplatin with or without paclitaxel on the viability of YD-8, YD-9, YD-38, YD-8/CIS, YD-9/CIS, and YD-38/CIS cells was determined by MTT assay (mean ± SD; n = 6). * p < 0.05 versus non-treated group in YD-8 or YD-8/CIS cells, # p < 0.05 versus non-treated group in YD-9 or YD-9/CIS cells, and $ p < 0.05 versus non-treated group in YD-38 or YD-38/CIS cells. (C) There was no synergistic effect. A fraction-affected versus CI plot (CIS/PAC) was determined using the Chou-Talalay and CompuSyn software.
Figure 2
Figure 2
Cisplatin (10 μg/mL) incubation for 6 h induces overexpression of FOXM1 mRNA and protein in cisplatin-resistant cell lines, whereas combination treatment attenuates this increase. (A) The expression of FOXM1 mRNA from these six cell lines treated with cisplatin in the presence or absence of paclitaxel was determined by real-time qRT-PCR (mean ± SD; n = 3). * p < 0.05 versus non-treated group, # p < 0.05 versus only cisplatin-treated cells, and $ p < 0.05 versus only paclitaxel-treated cells. (B) The expressions of FOXM1 and α-tubulin in cell lysates from these six cell lines treated with cisplatin in the presence and absence of paclitaxel were determined by Western blot assay. (C) Quantification of Western blot results.
Figure 3
Figure 3
Cisplatin (10 μg/mL) weakens the chemical sensitivity of paclitaxel (0.1 μg/mL), whereas co-treatment with FDI-6, a FOXM1 inhibitor, restores it in cisplatin-resistant cell lines. (A) The expression of FOXM1, poly (ADP-ribose) polymerase (PARP), and actin in cell lysates from the cisplatin-resistant cell lines treated with cisplatin in the presence and absence of paclitaxel and FDI-6 were determined by Western blot assay. (B) Quantification of Western blot results. (C) The cytotoxic effect of cisplatin with or without paclitaxel in cisplatin-resistant cell lines was determined by a propidium iodide (PI) staining assay. (D) Quantitative results for panel C (mean ± SD; n = 3). * p < 0.05 versus non-treated group, # p < 0.05 versus only cisplatin-treated cells, and $ p < 0.05 versus only paclitaxel-treated cells.
Figure 4
Figure 4
Treatment with FDI-6 in combination with cisplatin (10 μg/mL) and paclitaxel (0.10 μg/mL) for 24 h enhances apoptosis in cisplatin-resistant cell lines. (A) The fragmented DNA of apoptotic cells by each drug or combination treatment in cisplatin-resistant cell lines for 24 h was measured by a TUNEL assay. DNA strand breaks were measured by dual staining with rTdT enzyme (green fluorescence) and PI (red fluorescence). Data represent quantitative results for cells positive for rTdT enzyme in panel A of this figure. (B) Data represent quantitative results for panel A (mean ± SD; n = 3). * p < 0.05 versus non-treated group, # p < 0.05 versus only cisplatin-treated cells, and $ p < 0.05 versus only paclitaxel-treated cells. (C) Schematic diagram showing that cisplatin reduces paclitaxel-mediated apoptosis by overexpressing FOXM1 protein in cisplatin-resistant OSCC cancer cell lines.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bray F., Ferlay J., Soerjomataram I., Siegel R.L., Torre L.A., Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68:394–424. doi: 10.3322/caac.21492. - DOI - PubMed
    1. Montero P.H., Patel S.G. Cancer of the oral cavity. Surg. Oncol. Clin. N Am. 2015;24:491–508. doi: 10.1016/j.soc.2015.03.006. - DOI - PMC - PubMed
    1. Hartner L. Chemotherapy for Oral Cancer. Dent. Clin. North Am. 2018;62:87–97. doi: 10.1016/j.cden.2017.08.006. - DOI - PubMed
    1. Dasari S., Tchounwou P.B. Cisplatin in cancer therapy: Molecular mechanisms of action. Eur. J. Pharmacol. 2014;740:364–378. doi: 10.1016/j.ejphar.2014.07.025. - DOI - PMC - PubMed
    1. Zhang P., Zhang Z., Zhou X., Qiu W., Chen F., Chen W. Identification of genes associated with cisplatin resistance in human oral squamous cell carcinoma cell line. BMC Cancer. 2006;6:224. doi: 10.1186/1471-2407-6-224. - DOI - PMC - PubMed

MeSH terms

LinkOut - more resources