Proteomics analysis of human breast milk by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) coupled with mass spectrometry to assess breast cancer risk

Abstract

Breast cancer (BC) is one of the most common cancers and one of the most common causes for cancer-related mortality. Discovery of protein biomarkers associated with cancer is considered important for early diagnosis and prediction of the cancer risk. Protein biomarkers could be investigated by large-scale protein investigation or proteomics, using mass spectrometry (MS)-based techniques. Our group applies MS-based proteomics to study the protein pattern in human breast milk from women with BC and controls and investigates the alterations and dysregulations of breast milk proteins in comparison pairs of BC versus control. These dysregulated proteins might be considered potential future biomarkers of BC. Identification of potential biomarkers in breast milk may benefit young women without BC, but who could collect the milk for future assessment of BC risk. Previously we identified several dysregulated proteins in different sets of human breast milk samples from BC patients and controls using gel-based protein separation coupled with MS. Here, we performed 2D-PAGE coupled with nano-liquid chromatography-tandem MS (nanoLC-MS/MS) in a small-scale study on a set of six human breast milk pairs (three BC samples vs. three controls) and we identified several dysregulated proteins that have potential roles in cancer progression and might be considered potential BC biomarkers in the future.

Keywords: 2D-PAGE; biomarkers; breast cancer; breast milk; mass spectrometry; protein dysregulation; proteomics.

Figure 1:

Gel images of Coomassie blue-stained gels (Figure 1A: BC_1 vs. C_1, Figure 1B: BC_2 vs. C_2 and Figure 1C: BC_3 vs. C_3).

Figure 2:

Gel images of silver-stained gels (1 of 2 replicate gels for each sample) Figure 2A: BC_1 vs. C_1, Figure 2B: BC_2 vs. C_2 and Figure 2C: BC_3 vs. C_3).

Figure 3:

Gel difference images and spot numbering for: Total of the 546 analyzed spots (Figure 3A), Statistically significant dysregulated spots in BC_1 vs. control_1 (Figure 3B), Statistically significant dysregulated spots in BC_2 vs. control_2 (Figure 3C), Statistically significant dysregulated spots in BC_3 vs. control_3 (Figure 3D), Statistically significant dysregulated spots in averaged BC vs. averaged control (Figure 3E). upregulated spots in BC vs. control are shown in blue and downregulated spots in BC vs. control are shown in red.