Curcumin exerts its antitumor activity through regulation of miR-7/Skp2/p21 in nasopharyngeal carcinoma cells

Figures & data

Figure 1 Effect of curcumin on NPC cell growth and apoptosis.

Notes: (A) MTT assay following curcumin treatment of NPC cells’ growth. **P<0.05, compared to the control (DMSO treatment). (B) NPC cells were stained with Annexin V-FITC/PI and assessed with flow cytometry to determine apoptosis in NPC cells treated with curcumin.
Abbreviations: NPC, nasopharyngeal carcinoma; MTT, (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide); DMSO, dimethyl sulfoxide; FITC/PI, fluorescein isothiocyanate/propidium iodide; FL1-H, fluorescence 1-H; FL2-H, fluorescence 2-H.

Figure 2 Effect of curcumin on NPC cell cycle.

Notes: NPC cells were stained with PI and assessed with flow cytometry to determine cell cycle profiles of NPC cells after curcumin treatment. Curcumin induced NPC cell cycle arrest at G2/M phase. Green color: G0/G1 phase; brown color: S phase; blue color: G2/M phase.
Abbreviations: NPC, nasopharyngeal carcinoma; PI, propidium iodide.

Figure 3 Curcumin inhibited cell migration in NPC cells.

Notes: (A, B) Left panel: the inhibitory effect of curcumin on cell migration was measured using wound healing assay in CNE1 (A) and CNE2 (B) cells. Right panel: quantitation of wound healing results. **P<0.01, vs control (DMSO treatment).
Abbreviations: NPC, nasopharyngeal carcinoma; DMSO, dimethyl sulfoxide.

Figure 4 Curcumin inhibited cell invasion in NPC cells.

Notes: (A) Left panel: the inhibitory effect of curcumin on NPC cell invasion was assessed using transwell assay. The invaded cells in the membrane were stained with Wright-Giemsa. Right panel: quantitation transwell assay results. **P<0.01 vs control. (B) Transwell assay was performed to measure the cell invasion in NPC cells after curcumin treatment. The invaded cells in the membrane were stained with 4 μg/mL calcein AM in Hanks’ buffered saline at 37°C for 1 h.
Abbreviation: NPC, nasopharyngeal carcinoma.

Figure 5 Curcumin inhibited the expression of Skp2 in NPC cells.

Notes: (A) The expression of Skp2, p21, and p57 was measured in NPC cells following curcumin treatment. (B) Quantitative results are illustrated for panel (A). *P<0.05, **P<0.01, compared with control.
Abbreviation: NPC, nasopharyngeal carcinoma.

Figure 6 Curcumin upregulated miR-7 level in NPC cells.

Notes: (A) The expression of miR-7 was measured by miRNA real-time RT-PCR in NPC cells following curcumin treatment. (B) Left panel: the expression of Skp2, p21, and p57 was measured in NPC cells following transfection of miR-7 mimics. Right panel: quantitation of results in left panel. *P<0.05; **P<0.01, compared with control.
Abbreviations: NPC, nasopharyngeal carcinoma; RT-PCR, reverse transcription polymerase chain reaction; Ctrl, control.

Figure 7 miR-7 inhibitor enhanced cell growth and invasion in NPC cells.

Notes: (A) MTT assay was performed on NPC cells after curcumin treatment, miR-7 inhibitor transfection, or a combination of both. *P<0.05 compared to control; ^#P<0.05 compared to curcumin treatment alone or miR-7 inhibitor alone. CNE1 cells: 10 μM curcumin; CNE2 cells: 15 μM curcumin treatment. (B) Cell invasion was measured using transwell inserts with Matrigel in NPC cells after curcumin treatment or miR-7 inhibitor transfection, or a combination of both. (C) The expression of Skp2 was measured in NPC cells after miR-7 inhibitor transfection and curcumin treatment.
Abbreviations: NPC, nasopharyngeal carcinoma; MTT, (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide); Ctrl, control.