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Mammaglobin as a potential molecular target for breast cancer drug delivery.

Zuo L, Li L, Wang Q, Fleming TP, You S - Cancer Cell Int. (2009)

Bottom Line: Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule.We provided several evidences to demonstrate the presence of the membrane-associated MAM.To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL.

View Article: PubMed Central - HTML - PubMed

Affiliation: Atlanta Research and Education Foundation, Atlanta VA Medical Center (151), Decatur, GA 30033, USA. arefzuo@gmail.com

ABSTRACT

Background: Mammaglobin (MAM) has been used as a specific molecular marker for breast cancer diagnosis. Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule. Some of the strategies are based upon an essential but not demonstrated hypothesis - mammaglobin is associated with the surface of breast cancer cells, which strongly disputes the therapeutic strategies.

Results: We conducted a computer-based predictive analysis and identified a small fragment at the N-end of MAM as a potential transmembrane domain. We provided several evidences to demonstrate the presence of the membrane-associated MAM. We isolated the membrane protein components from known MAM positive breast cancer cells (MDA-MB361 and MDA-MB415). We showed that about 22-64% of MAM proteins, depending upon the types of the cancer cells, directly attached on the membrane of breast cancer cells, by Western blotting assays. To directly visualize the presence of the membrane-bound MAM protein, we incubated the MAM positive cancer cells with FITC labeled anti-MAM antibody, and observed clear fluorescent signals on the surface of the cells. In studying the MAM protein distribution in human breast cancer tissues, we first identified two immunostain patterns that are associated with the membrane-bound MAM: the membrane stain pattern and luminary surface stain pattern. To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL. Specific binding and cytotoxicity of the MAM targeted and Dox loaded LDL was tested in the MAM positive breast cancer cells in vitro.

Conclusion: We first showed that some of MAM protein directly associated with the surface of breast cancer cells. The membrane-associated MAM protein may be utilized as a useful molecular marker for breast cancer targeted drug delivery.

No MeSH data available.


Related in: MedlinePlus

Computer-assisted structural analysis of MAM protein. The predicted secondary structure of MAM/lipophilin B dimmer (upper left) and MAM alone (upper right) created by the HMM-based protein structure prediction program, SAM-T02. A helix fragment at the N-end of MAM protein is predicted as a transmembrane domain (the dark blue helix). The protein sequence shown is the N-terminal end of MAM. "+" Inside loop; "-" Outside loop; "O" Outside helix cap; "X" Central transmembrane helix segment; "I" Inside helix cap.
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Figure 1: Computer-assisted structural analysis of MAM protein. The predicted secondary structure of MAM/lipophilin B dimmer (upper left) and MAM alone (upper right) created by the HMM-based protein structure prediction program, SAM-T02. A helix fragment at the N-end of MAM protein is predicted as a transmembrane domain (the dark blue helix). The protein sequence shown is the N-terminal end of MAM. "+" Inside loop; "-" Outside loop; "O" Outside helix cap; "X" Central transmembrane helix segment; "I" Inside helix cap.

Mentions: Proteins are usually composed of one or more functional regions, or domains. The identification of domains that occur within proteins can provide insights into their functions. The meta-server technique represents one of the major progresses in the field of protein tertiary structure prediction. To predict the secondary structure of the protein, we conducted a predictive analysis on the MAM protein sequence with the SAM-T02 [15]. Based on the predictive analysis, we identified five helixes or domains on the protein (Figure 1). Among these domains, the fragment at the N-end of MAM protein (the 9–18th amino acid residues) is different from those of the lipophilin and other uteroglobin family proteins (such as pheromaxein C subunit, prostatein C3 subunit, uteroglobin). This fragment mostly consists of the hydrophobic amino acids and is predicted as the trans-membrane helix. So we proposed that MAM proteins are, at least some if not all, associated with cell membrane.


Mammaglobin as a potential molecular target for breast cancer drug delivery.

Zuo L, Li L, Wang Q, Fleming TP, You S - Cancer Cell Int. (2009)

Computer-assisted structural analysis of MAM protein. The predicted secondary structure of MAM/lipophilin B dimmer (upper left) and MAM alone (upper right) created by the HMM-based protein structure prediction program, SAM-T02. A helix fragment at the N-end of MAM protein is predicted as a transmembrane domain (the dark blue helix). The protein sequence shown is the N-terminal end of MAM. "+" Inside loop; "-" Outside loop; "O" Outside helix cap; "X" Central transmembrane helix segment; "I" Inside helix cap.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662795&req=5

Figure 1: Computer-assisted structural analysis of MAM protein. The predicted secondary structure of MAM/lipophilin B dimmer (upper left) and MAM alone (upper right) created by the HMM-based protein structure prediction program, SAM-T02. A helix fragment at the N-end of MAM protein is predicted as a transmembrane domain (the dark blue helix). The protein sequence shown is the N-terminal end of MAM. "+" Inside loop; "-" Outside loop; "O" Outside helix cap; "X" Central transmembrane helix segment; "I" Inside helix cap.
Mentions: Proteins are usually composed of one or more functional regions, or domains. The identification of domains that occur within proteins can provide insights into their functions. The meta-server technique represents one of the major progresses in the field of protein tertiary structure prediction. To predict the secondary structure of the protein, we conducted a predictive analysis on the MAM protein sequence with the SAM-T02 [15]. Based on the predictive analysis, we identified five helixes or domains on the protein (Figure 1). Among these domains, the fragment at the N-end of MAM protein (the 9–18th amino acid residues) is different from those of the lipophilin and other uteroglobin family proteins (such as pheromaxein C subunit, prostatein C3 subunit, uteroglobin). This fragment mostly consists of the hydrophobic amino acids and is predicted as the trans-membrane helix. So we proposed that MAM proteins are, at least some if not all, associated with cell membrane.

Bottom Line: Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule.We provided several evidences to demonstrate the presence of the membrane-associated MAM.To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL.

View Article: PubMed Central - HTML - PubMed

Affiliation: Atlanta Research and Education Foundation, Atlanta VA Medical Center (151), Decatur, GA 30033, USA. arefzuo@gmail.com

ABSTRACT

Background: Mammaglobin (MAM) has been used as a specific molecular marker for breast cancer diagnosis. Recently, several groups of researchers proposed a number of therapeutic strategies targeting this molecule. Some of the strategies are based upon an essential but not demonstrated hypothesis - mammaglobin is associated with the surface of breast cancer cells, which strongly disputes the therapeutic strategies.

Results: We conducted a computer-based predictive analysis and identified a small fragment at the N-end of MAM as a potential transmembrane domain. We provided several evidences to demonstrate the presence of the membrane-associated MAM. We isolated the membrane protein components from known MAM positive breast cancer cells (MDA-MB361 and MDA-MB415). We showed that about 22-64% of MAM proteins, depending upon the types of the cancer cells, directly attached on the membrane of breast cancer cells, by Western blotting assays. To directly visualize the presence of the membrane-bound MAM protein, we incubated the MAM positive cancer cells with FITC labeled anti-MAM antibody, and observed clear fluorescent signals on the surface of the cells. In studying the MAM protein distribution in human breast cancer tissues, we first identified two immunostain patterns that are associated with the membrane-bound MAM: the membrane stain pattern and luminary surface stain pattern. To test whether the membrane-associated MAM can serve as a molecular target for drug delivery, we conjugated anti-MAM antibody to human low-density lipoprotein (LDL) and loaded doxorubicin (Dox) in the core of LDL. Specific binding and cytotoxicity of the MAM targeted and Dox loaded LDL was tested in the MAM positive breast cancer cells in vitro.

Conclusion: We first showed that some of MAM protein directly associated with the surface of breast cancer cells. The membrane-associated MAM protein may be utilized as a useful molecular marker for breast cancer targeted drug delivery.

No MeSH data available.


Related in: MedlinePlus