MiR-210 expression reverses radioresistance of stem-like cells of oesophageal squamous cell carcinoma

Table 1 Clinical and pathological data and levels of miR-210 expression in the selected oesophageal squamous cell carcinoma patients

Clinical feature		n	MiR-210 expression level		Local recurrence time
			Low	High	Early	Late and not
Pathological grade	II	11	7	6	2	9
	III	26	23	1b	17	9b
T-stage	II	13	11	2	3	10a
	III	24	19	5	16	8
Lymph node infiltration	+	16	12	4	11	5
	-	21	18	3	8	13

^aP < 0.05,

^bP < 0.01, patients vs the patients with miR-210 expression. All of the patients were male, with a median age of 54 (range, 42-71) years. The level of miR-210 expression was determined using quantitative reverse transcription-polymerase chain reaction. The level of expression in the oesophageal squamous cell carcinoma tissue was compared with that in the same patient’s para-tumorous normal oesophageal tissue. The endpoint of the follow-up period was when a local recurrence arose or at least 35 mo, and 18 mo was chosen to distinguish early and non-early recurrences.

Table 2 Rates of clone formation of radiated TE-1R cells

Cell type	0 Gy	2 Gy	4 Gy	6 Gy	8 Gy
PmiR-210	100.00% ± 0.77%	52.49% ± 0.22%	21.82% ± 0.17%a	3.17% ± 0.11%a	1.27% ± 0.03%a
Ctrl	100.00% ± 0.14%	58.17% ± 0.16%	26.88% ± 0.36%	7.51% ± 0.09%	2.49% ± 0.01%

^aP < 0.05, vs Ctrl. PmiR-210: TE-1R cells transfected with an miR-210 mimic; Ctrl: TE-1R cells transfected with a nonsense sequence. The experiments were performed in triplicate.

Table 3 Radiobiological indices of the pmiR-210 and Ctrl cells

	D0	Dq	N	SF2
PmiR-210	1.73% ± 0.01%	1.56% ± 0.02%a	1.97% ± 0.03%a	43.62% ± 0.14%a
Ctrl	1.75% ± 0.02%	1.89% ± 0.13%	3.13% ± 0.07%	67.83% ± 0.16%

^aP < 0.05, vs Ctrl. PmiR-210: TE-1R cells transfected with the miR-210 mimic; Ctrl: TE-1R cells transfected with a nonsense sequence. The experiments were performed in triplicate. D₀: Mean lethal dose; D_q: Quasi-threshold dose; N: Extrapolated number; SF₂: Survival fraction after 2-Gy irradiation. The lower D_q and N of the pmiR-210 cells compared with those of the Ctrl cells indicate a less efficient repair of radiation damage. A low SF₂ value indicates a level of high sensitivity to radiotherapy.