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Characterization of β2-microglobulin expression in different types of breast cancer.

Li K, Du H, Lian X, Yang S, Chai D, Wang C, Yang R, Chen X - BMC Cancer (2014)

Bottom Line: The β2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P<0.01), and have no significant correlation with age, clinical stage or lymph node metastasis.There was a significant difference demonstrated in β2-M protein expression in the four breast cancer molecular subtypes (P<0.05), and between the ER+ and ER- groups (P<0.01); however, no significant difference was demonstrated between the HER-2+ and HER-2- groups. β2-M protein expression had a negative correlation with ER protein expression (P<0.01), a positive correlation with p53 protein expression (P<0.01), and no correlation with Ki67 protein expression. β2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2-).In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER-, PR- and HER-2-), which is consistent with the silencing effect seen at the protein level. β2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine Biotechnology, Medicine and Science Research Institute of Gansu Province, Lanzhou, China. likesheng63@hotmail.com.

ABSTRACT

Background: Βeta-2-microglobulin (β2-M) has been demonstrated as a growth factor and signaling molecule in breast cancer and leukemia. The purpose of the study is to characterize β2-M expression in molecular subtypes of breast cancer, thereby investigating the mechanism of β2-M action in breast cancer.

Methods: β2-M and B-Cell Lymphoma/Leukemia 2 (Bcl-2) transcript expression levels in breast cancer tissue and the corresponding normal tissue were quantified using real-time PCR. The protein expression levels of β2-M, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), tumor protein 53 (p53) and Ki67 were determined by immunohistochemical (IHC) staining. Following silencing of the β2-M by siRNA, the levels of Bcl-2, ER, PR and HER-2 transcripts and the protein expression levels in human breast cancer cells were measured by real-time PCR and western blotting, respectively.

Results: The expression of β2-M transcripts demonstrated no significant differences between the four breast cancer molecular subtypes and no significant correlations with age, clinical stage or lymph node metastasis. β2-M transcript expression demonstrated a positive correlation when compared to Bcl-2 transcript expression (P<0.05). The β2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P<0.01), and have no significant correlation with age, clinical stage or lymph node metastasis. There was a significant difference demonstrated in β2-M protein expression in the four breast cancer molecular subtypes (P<0.05), and between the ER+ and ER- groups (P<0.01); however, no significant difference was demonstrated between the HER-2+ and HER-2- groups. β2-M protein expression had a negative correlation with ER protein expression (P<0.01), a positive correlation with p53 protein expression (P<0.01), and no correlation with Ki67 protein expression. β2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2-). In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER-, PR- and HER-2-), which is consistent with the silencing effect seen at the protein level.

Conclusions: β2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

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Related in: MedlinePlus

Silencing of theβ2-Mgene by siRNAs in breast cancer cells. A) β2-M siRNAs significantly inhibited the Bcl-2 mRNA expression, but did not inhibit the ER, PR, and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2−); B) β2-M siRNAs significantly up-regulated the Bcl-2 and HER-2 mRNA expression in MDA-MB-231 cells (ER−, PR− and HER-2−); C) ER, HER-2, PR and Bcl-2 protein levels in MCF-7 cells, with or without β2-M siRNAs; D) ER, HER-2, PR and Bcl-2 protein levels in MDA-MB-231 cells, with or without β2-M siRNAs.
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Fig2: Silencing of theβ2-Mgene by siRNAs in breast cancer cells. A) β2-M siRNAs significantly inhibited the Bcl-2 mRNA expression, but did not inhibit the ER, PR, and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2−); B) β2-M siRNAs significantly up-regulated the Bcl-2 and HER-2 mRNA expression in MDA-MB-231 cells (ER−, PR− and HER-2−); C) ER, HER-2, PR and Bcl-2 protein levels in MCF-7 cells, with or without β2-M siRNAs; D) ER, HER-2, PR and Bcl-2 protein levels in MDA-MB-231 cells, with or without β2-M siRNAs.

Mentions: Silencing effects of the pre-designed β2-M siRNAs were examined in MCF-7 and MDA-MB-231 cells, and a scrambled siRNA was used as the negative control. All three siRNAs showed a significant silencing effect (P < 0.01) and knocked down 80 to 98% of the β2-M mRNA in comparison with the scrambled siRNA (Figure 2). Among the β2-M siRNAs tested, only the siR-3 siRNA showed a significant effect on downstream genes and therefore this siRNA was selected for silencing of the β2-M gene. The mRNA transcript and protein expression levels of β2-M, ER, PR, HER-2 and Bcl-2 were detected by real-time PCR and western blotting after β2-M silencing in MCF-7 and MDA-MB-231 cells. As shown in Figure 2, siR-3 significantly inhibited Bcl-2 mRNA expression, but did not inhibit the levels of ER, PR, and HER-2 mRNA expression in MCF-7 cells, which is consistent with the silencing effect at the protein level. The Bcl-2 and HER-2 mRNAs were significantly up-regulated by siR-3 silencing in MDA-MB-231 cells, which is also consistent with the silencing effect at the protein level (Figure 2).Figure 2


Characterization of β2-microglobulin expression in different types of breast cancer.

Li K, Du H, Lian X, Yang S, Chai D, Wang C, Yang R, Chen X - BMC Cancer (2014)

Silencing of theβ2-Mgene by siRNAs in breast cancer cells. A) β2-M siRNAs significantly inhibited the Bcl-2 mRNA expression, but did not inhibit the ER, PR, and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2−); B) β2-M siRNAs significantly up-regulated the Bcl-2 and HER-2 mRNA expression in MDA-MB-231 cells (ER−, PR− and HER-2−); C) ER, HER-2, PR and Bcl-2 protein levels in MCF-7 cells, with or without β2-M siRNAs; D) ER, HER-2, PR and Bcl-2 protein levels in MDA-MB-231 cells, with or without β2-M siRNAs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4197271&req=5

Fig2: Silencing of theβ2-Mgene by siRNAs in breast cancer cells. A) β2-M siRNAs significantly inhibited the Bcl-2 mRNA expression, but did not inhibit the ER, PR, and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2−); B) β2-M siRNAs significantly up-regulated the Bcl-2 and HER-2 mRNA expression in MDA-MB-231 cells (ER−, PR− and HER-2−); C) ER, HER-2, PR and Bcl-2 protein levels in MCF-7 cells, with or without β2-M siRNAs; D) ER, HER-2, PR and Bcl-2 protein levels in MDA-MB-231 cells, with or without β2-M siRNAs.
Mentions: Silencing effects of the pre-designed β2-M siRNAs were examined in MCF-7 and MDA-MB-231 cells, and a scrambled siRNA was used as the negative control. All three siRNAs showed a significant silencing effect (P < 0.01) and knocked down 80 to 98% of the β2-M mRNA in comparison with the scrambled siRNA (Figure 2). Among the β2-M siRNAs tested, only the siR-3 siRNA showed a significant effect on downstream genes and therefore this siRNA was selected for silencing of the β2-M gene. The mRNA transcript and protein expression levels of β2-M, ER, PR, HER-2 and Bcl-2 were detected by real-time PCR and western blotting after β2-M silencing in MCF-7 and MDA-MB-231 cells. As shown in Figure 2, siR-3 significantly inhibited Bcl-2 mRNA expression, but did not inhibit the levels of ER, PR, and HER-2 mRNA expression in MCF-7 cells, which is consistent with the silencing effect at the protein level. The Bcl-2 and HER-2 mRNAs were significantly up-regulated by siR-3 silencing in MDA-MB-231 cells, which is also consistent with the silencing effect at the protein level (Figure 2).Figure 2

Bottom Line: The β2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P<0.01), and have no significant correlation with age, clinical stage or lymph node metastasis.There was a significant difference demonstrated in β2-M protein expression in the four breast cancer molecular subtypes (P<0.05), and between the ER+ and ER- groups (P<0.01); however, no significant difference was demonstrated between the HER-2+ and HER-2- groups. β2-M protein expression had a negative correlation with ER protein expression (P<0.01), a positive correlation with p53 protein expression (P<0.01), and no correlation with Ki67 protein expression. β2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2-).In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER-, PR- and HER-2-), which is consistent with the silencing effect seen at the protein level. β2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine Biotechnology, Medicine and Science Research Institute of Gansu Province, Lanzhou, China. likesheng63@hotmail.com.

ABSTRACT

Background: Βeta-2-microglobulin (β2-M) has been demonstrated as a growth factor and signaling molecule in breast cancer and leukemia. The purpose of the study is to characterize β2-M expression in molecular subtypes of breast cancer, thereby investigating the mechanism of β2-M action in breast cancer.

Methods: β2-M and B-Cell Lymphoma/Leukemia 2 (Bcl-2) transcript expression levels in breast cancer tissue and the corresponding normal tissue were quantified using real-time PCR. The protein expression levels of β2-M, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), tumor protein 53 (p53) and Ki67 were determined by immunohistochemical (IHC) staining. Following silencing of the β2-M by siRNA, the levels of Bcl-2, ER, PR and HER-2 transcripts and the protein expression levels in human breast cancer cells were measured by real-time PCR and western blotting, respectively.

Results: The expression of β2-M transcripts demonstrated no significant differences between the four breast cancer molecular subtypes and no significant correlations with age, clinical stage or lymph node metastasis. β2-M transcript expression demonstrated a positive correlation when compared to Bcl-2 transcript expression (P<0.05). The β2-M protein expression was significantly higher in breast cancer when compared with benign breast tumors (P<0.01), and have no significant correlation with age, clinical stage or lymph node metastasis. There was a significant difference demonstrated in β2-M protein expression in the four breast cancer molecular subtypes (P<0.05), and between the ER+ and ER- groups (P<0.01); however, no significant difference was demonstrated between the HER-2+ and HER-2- groups. β2-M protein expression had a negative correlation with ER protein expression (P<0.01), a positive correlation with p53 protein expression (P<0.01), and no correlation with Ki67 protein expression. β2-M silencing significantly inhibited Bcl-2 mRNA expression, but did not inhibit ER, PR and HER-2 mRNA expression in MCF-7 cells (ER+, PR+ and HER-2-). In addition, Bcl-2 and HER-2 mRNA expression were significantly up-regulated in MDA-MB-231 cells (ER-, PR- and HER-2-), which is consistent with the silencing effect seen at the protein level.

Conclusions: β2-M expression demonstrated a significant difference in the four breast cancer molecular subtypes, and may be related to apoptosis regulation in breast cancer.

Show MeSH
Related in: MedlinePlus