Suppression of MD2 inhibits breast cancer in vitro and in vivo

Abstract

Purpose: To explore the effects of the intervening measure targeting myeloid differentiation 2 (MD2) on breast cancer progression in vitro and in vivo.

Methods: The expression of MD2 in normal breast cells (Hs 578Bst) and three kinds of breast carcinoma cell lines (MCF-7, MDA-MB-231 s and 4T1) were detected by western blot. MTT assay was used to detect the proliferation of 4T1 cells treated by L6H21, cell migration and invasion was measured by wound healing assay and trans-well matrigel invasion assay, respectively. In addition, to further study the role of MD2 in tumor progression, we assessed the effects of inhibition of MD2 on the progression of xenograft tumors in vivo.

Results: The expression of MD2 is much higher in MDA-MB-231 s and 4T1cells than that in normal breast cells (Hs 578Bst) or MCF-7 cells (p < 0.05). In vitro, suppression of MD2 by L6H21 has a significant inhibition of proliferation, migration and invasion in 4T1 cells in dose-dependent manner. In vivo, L6H21 pretreatment significantly improved survival of 4T1-bearing mice (p < 0.05). Additionally, we also observed that none of the mice died from the toxic effect of 10 mg kg^-1 L6H21 in 60 days.

Conclusion: Overall, this work indicates that suppression of MD2 shows progression inhibition in vitro and significantly prolong survival in vivo. These findings provide the potential experimental evidence for using MD2 as a therapeutic target of breast carcinoma.

Keywords: Breast neoplasms; Invasion; Migration; Myeloid differentiation 2 (MD2); Proliferation.

Fig. 1

MD2 is highly expressed in MDA-MB-231 s and 4T1 cells (p < 0.05 compared to that expressed in Hs 578Bst cells and MCF-7 cells)

Fig. 2

MTT assay showed that L6H21 (10 μM, 30 μM and 100 μM) significantly inhibited the proliferation of 4T1 cells in dose-dependent manner

Fig. 3

L6H21 inhibition of 4T1 cells migration and invasion. a L6H21 significantly inhibited the migration of 4T1 cells, The images (100 ×) were obtained by microscope. b L6H21 significantly inhibited the invasion of 4T1 cells (400 ×). In 5 μM L6H21 group, there were a few migrating cells observed compared to that of control group. While in 10 μM L6H21 group and in 1 μg ml⁻¹ anti-MD2 group, there were almost no migrating cells observed

Fig. 4

L6H21 enhanced survival in nude mice. Male BALB/c mice were randomly divided into four groups (n = 8 per group). 4T1-bearing mice were injected with 3 × 10⁵ 4T1 cells (i.v. through the tail vein) 3 days after being treated with L6H21 (at 10 mg kg⁻¹ or 5 mg kg⁻¹) and saline by intragastric administration, respectively, and the mice of the fourth group were only treated with L6H21 at 10 mg kg⁻¹ but without inoculation of 4T1 cells. Each group of mice were then intragastrically administrated per day until death or day 60. The survival curve was made to analyse the survival rate

Fig. 5

Body weight data after treatment. The body weight data after treatment were collected when mice were dead or at day 60. **p < 0.05 compared to the control group