MUC1 Overexpression Lysate

HEK293T cells in 10-cm dishes were transiently transfected with a non-lipid polymer transfection reagent specially designed and manufactured for large volume DNA transfection. Transfected cells were cultured for 48hrs before collection. The cells were lysed in modified RIPA buffer (25mM Tris-HCl pH7.6, 150mM NaCl, 1% NP-40, 1mM EDTA, 1xProteinase inhibitor cocktail mix, 1mM PMSF and 1mM Na3VO4, and then centrifuged to clarify the lysate. Protein concentration was measured by BCA protein assay kit.

Mucin 1 (MUC1), also known as episialin, EMA (epithelial membrane antigen), PEM (polymorphic epithelial mucin), and CA-15-3 antigen, is a membrane-bound type I transmembrane glycoprotein (1,2). MUC1 is typically expressed in the luminal or glandular epithelial cells of the gastrointestinal tract, breast, lungs, and more, and is often overexpressed in epithelial cancers, but also serves a protective role against infection and helps regulate inflammatory response (2,3). Human MUC1 is 1255 amino acids (aa) in length with a theoretical molecular weight of 122 kDa; however, depending on the amount of glycosylation can weigh between 250 - 500 kDa (2,4). Structurally, MUC1 consists of a N-terminal domain which contains a signal peptide, a variable number tandem repeat region (VNTR), and a SEA domain, as well a C-terminal domain which has the extracellular domain (ECD), transmembrane domain (TMD), and cytoplasmic tail (CT) (2,3). The VNTR is comprised of between 25 - 125 repeats of a 20 aa conserved sequence (3). MUC1 is heavily O-glycosylated in the VNTR and has moderate N-glycosylation sites following the VNTR and in the ECD (2). Glycosylation contributes to MUC1's functional properties (2). The MUC1 gene contains seven exons, giving rise to several MUC1 isoforms as a result of alternative splicing (2).

Overexpression of mucins, including MUC1, is a feature of many epithelial cancers (1,3,5,6). The presence of truncated glycan structures called tumor-associated carbohydrate antigens (TACAs) on MUC1 play a role in cancer progression and a loss of apical-basal polarity (5). Carbohydrate-binding partners called lectins are the primary binding partners of TACAs that give rise to the pro-tumor microenvironment and metastasis (5). Given this unique feature, TACAs are a potential target for cancer immunotherapies (5). There are a number of vaccines, drugs, and antibodies targeting MUC1 for treatment of a variety of cancers including breast, lung, and prostate (6). In addition to a role in cancer progression, MUC1, and specifically the CT portion, has been shown to have a positive, anti-inflammatory role in a variety of lung and airway infections (7).

References

1. Khodabakhsh, F., Merikhian, P., Eisavand, M. R., & Farahmand, L. (2021). Crosstalk between MUC1 and VEGF in angiogenesis and metastasis: a review highlighting roles of the MUC1 with an emphasis on metastatic and angiogenic signaling. Cancer cell international. https://doi.org/10.1186/s12935-021-01899-8

2. Nath, S., & Mukherjee, P. (2014). MUC1: a multifaceted oncoprotein with a key role in cancer progression. Trends in molecular medicine. https://doi.org/10.1016/j.molmed.2014.02.007

3. Dhar, P., & McAuley, J. (2019). The Role of the Cell Surface Mucin MUC1 as a Barrier to Infection and Regulator of Inflammation. Frontiers in cellular and infection microbiology. https://doi.org/10.3389/fcimb.2019.00117

4. Uniprot (P15941)

5. Beckwith, D. M., & Cudic, M. (2020). Tumor-associated O-glycans of MUC1: Carriers of the glyco-code and targets for cancer vaccine design. Seminars in immunology. https://doi.org/10.1016/j.smim.2020.101389

6. Almasmoum H. (2021). The Roles of Transmembrane Mucins Located on Chromosome 7q22.1 in Colorectal Cancer. Cancer management and research. https://doi.org/10.2147/CMAR.S299089

7. Ballester, B., Milara, J., & Cortijo, J. (2021). The role of mucin 1 in respiratory diseases. European respiratory review : an official journal of the European Respiratory Society. https://doi.org/10.1183/16000617.0149-2020

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Lysates are guaranteed for 6 months from date of receipt.

Array NBP2-08671

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