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Anti-matrix metalloproteinase-9 DNAzyme decreases tumor growth in the MMTV-PyMT mouse model of breast cancer.

Hallett MA, Teng B, Hasegawa H, Schwab LP, Seagroves TN, Pourmotabbed T - Breast Cancer Res. (2013)

Bottom Line: DNAzymes or catalytic oligonucleotides are new classes of gene targeting molecules that bind and cleave a specific mRNA, resulting in decreased protein expression.AM9D specifically inhibited expression of MMP-9 in MDA-MB-231 cells resulting in reduced invasive property of these cells by 43%.These results show that targeting and down regulation of MMP-9 by AM9D could prove useful as a therapy against breast carcinoma tumor growth and invasion.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Despite continued improvements in diagnosis, surgical techniques, and chemotherapy, breast cancer patients are still overcome by cancer metastasis. Tumor cell proliferation, invasion and metastasis are mediated, at least in part, through degradation of basement membrane by neutral matrix metalloproteinases (MMP) produced by tumor and stromal cells. Evidence suggests that MMP-9 plays a significant role in breast tumor cell invasion and metastasis. DNAzymes or catalytic oligonucleotides are new classes of gene targeting molecules that bind and cleave a specific mRNA, resulting in decreased protein expression.

Methods: The application of anti-MMP-9 DNAzyme (AM9D) for the treatment of primary and metastatic breast cancer was evaluated in vitro and in vivo using MDA-MB-231 cells and the MMTV-PyMT transgenic breast cancer mouse model. Spontaneously developed mammary tumors in MMTV-PyMT transgenic mice were treated intratumorally with naked AM9D, once a week for 4 weeks. The stability of DNAzyme was determined in vitro and in vivo using fluorescently labeled DNAzyme.

Results: AM9D specifically inhibited expression of MMP-9 in MDA-MB-231 cells resulting in reduced invasive property of these cells by 43%. Weekly intratumoral treatment of spontaneously developed mammary tumors in MMTV-PyMT transgenic mice was sufficient to significantly reduce the rate of tumor growth and final tumor load in a dose dependent and statistically significant manner (P < 0.05). This decrease in tumor growth was correlated with decreased MMP-9 protein production within the treated tumor tissues. Tumors treated with AM9D were also less vascularized and contained more apoptotic cells compared to control and untreated tumors.

Conclusions: These results show that targeting and down regulation of MMP-9 by AM9D could prove useful as a therapy against breast carcinoma tumor growth and invasion.

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Related in: MedlinePlus

Immunohistochemical staining for metalloproteinase (MMP)-9 and α-smooth muscle actin (α-SMA) in mammary tumor sections. Tumors were resected from mice and double stained with antibodies to α-SMA to detect stromal cells (A) and MMP-9 (B). When channels were merged (C), these data show that MMP-9 was present in both stromal and tumor cells. Magnification 200×; scale bar is equivalent to 100 µm.
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Figure 2: Immunohistochemical staining for metalloproteinase (MMP)-9 and α-smooth muscle actin (α-SMA) in mammary tumor sections. Tumors were resected from mice and double stained with antibodies to α-SMA to detect stromal cells (A) and MMP-9 (B). When channels were merged (C), these data show that MMP-9 was present in both stromal and tumor cells. Magnification 200×; scale bar is equivalent to 100 µm.

Mentions: To confirm the presence of MMP-9 protein in late-stage mammary carcinomas, tumors were harvested from MMTV-PyMT transgenic females at 12 weeks of age. Tumor sections were stained with antibodies to both α-SMA, a marker for stromal myofibroblasts, and MMP-9. IHC analysis demonstrated the presence of MMP-9 in the tumor epithelium, including areas highly populated with stromal fibroblasts (Figure 2). It is also likely that MMP-9 is produced by the tumor-associated macrophages that are known to be present in PyMT tumors [41,42].


Anti-matrix metalloproteinase-9 DNAzyme decreases tumor growth in the MMTV-PyMT mouse model of breast cancer.

Hallett MA, Teng B, Hasegawa H, Schwab LP, Seagroves TN, Pourmotabbed T - Breast Cancer Res. (2013)

Immunohistochemical staining for metalloproteinase (MMP)-9 and α-smooth muscle actin (α-SMA) in mammary tumor sections. Tumors were resected from mice and double stained with antibodies to α-SMA to detect stromal cells (A) and MMP-9 (B). When channels were merged (C), these data show that MMP-9 was present in both stromal and tumor cells. Magnification 200×; scale bar is equivalent to 100 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672740&req=5

Figure 2: Immunohistochemical staining for metalloproteinase (MMP)-9 and α-smooth muscle actin (α-SMA) in mammary tumor sections. Tumors were resected from mice and double stained with antibodies to α-SMA to detect stromal cells (A) and MMP-9 (B). When channels were merged (C), these data show that MMP-9 was present in both stromal and tumor cells. Magnification 200×; scale bar is equivalent to 100 µm.
Mentions: To confirm the presence of MMP-9 protein in late-stage mammary carcinomas, tumors were harvested from MMTV-PyMT transgenic females at 12 weeks of age. Tumor sections were stained with antibodies to both α-SMA, a marker for stromal myofibroblasts, and MMP-9. IHC analysis demonstrated the presence of MMP-9 in the tumor epithelium, including areas highly populated with stromal fibroblasts (Figure 2). It is also likely that MMP-9 is produced by the tumor-associated macrophages that are known to be present in PyMT tumors [41,42].

Bottom Line: DNAzymes or catalytic oligonucleotides are new classes of gene targeting molecules that bind and cleave a specific mRNA, resulting in decreased protein expression.AM9D specifically inhibited expression of MMP-9 in MDA-MB-231 cells resulting in reduced invasive property of these cells by 43%.These results show that targeting and down regulation of MMP-9 by AM9D could prove useful as a therapy against breast carcinoma tumor growth and invasion.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Despite continued improvements in diagnosis, surgical techniques, and chemotherapy, breast cancer patients are still overcome by cancer metastasis. Tumor cell proliferation, invasion and metastasis are mediated, at least in part, through degradation of basement membrane by neutral matrix metalloproteinases (MMP) produced by tumor and stromal cells. Evidence suggests that MMP-9 plays a significant role in breast tumor cell invasion and metastasis. DNAzymes or catalytic oligonucleotides are new classes of gene targeting molecules that bind and cleave a specific mRNA, resulting in decreased protein expression.

Methods: The application of anti-MMP-9 DNAzyme (AM9D) for the treatment of primary and metastatic breast cancer was evaluated in vitro and in vivo using MDA-MB-231 cells and the MMTV-PyMT transgenic breast cancer mouse model. Spontaneously developed mammary tumors in MMTV-PyMT transgenic mice were treated intratumorally with naked AM9D, once a week for 4 weeks. The stability of DNAzyme was determined in vitro and in vivo using fluorescently labeled DNAzyme.

Results: AM9D specifically inhibited expression of MMP-9 in MDA-MB-231 cells resulting in reduced invasive property of these cells by 43%. Weekly intratumoral treatment of spontaneously developed mammary tumors in MMTV-PyMT transgenic mice was sufficient to significantly reduce the rate of tumor growth and final tumor load in a dose dependent and statistically significant manner (P < 0.05). This decrease in tumor growth was correlated with decreased MMP-9 protein production within the treated tumor tissues. Tumors treated with AM9D were also less vascularized and contained more apoptotic cells compared to control and untreated tumors.

Conclusions: These results show that targeting and down regulation of MMP-9 by AM9D could prove useful as a therapy against breast carcinoma tumor growth and invasion.

Show MeSH
Related in: MedlinePlus