*2.3. Mass Spectrometry-Based Proteomics of MCF7 and MDA-MB-231 Cells Treated with B. jararaca Venom*

Protein identification was performed analyzing the raw data using the MaxQuant software against the *Homo sapiens* database downloaded from Uniprot. Analysis of the MCF7 cell line treated with different venom concentrations allowed the identification of 789 proteins from which 704 proteins were identified in the control group (non-venom treatment), 725 proteins were identified in cells treated with 0.63 μg/mL of venom, and 713 proteins were identified in the cells treated with 2.5 μg/mL of venom. Comparative analysis of the identified proteins showed that among all of the 789 proteins identified, 637 proteins were in common to all conditions, 657 proteins were in common between the control and the 0.63 μg/mL venom treatment, 656 proteins were in common between control and the 2.5 μg/mL venom treatment, and 677 proteins were in common between the 0.63 μg/mL and 2.5 μg/mL venom treatments (Figure 2a, Table S1a). In addition, we also identified exclusive proteins in each condition: 28 proteins in the control group, 28 proteins in 0.63 μg/mL venom treatment, and 17 proteins exclusive in the 2.5 μg/mL venom treatment (Figure 2a, Table S1a).

**Figure 2.** Diagrammatic representation of the comparative analysis of identified proteins under the three conditions: no venom control group, low venom dose at 0.63 μg/mL and high venom sub-toxic dose of 2.5 μg/mL of *B. jararaca* venom. (**a**) MCF7 and (**b**) MDA-MB-231.

In the MDA-MB-231 cell line, mass spectrometry-based proteomics analysis allowed us to identify a total of 1093 proteins from which 1006 proteins in the control group, 992 proteins in the cells treated with 0.63 μg/mL of venom, and 978 proteins in the cells treated with 2.5 μg/mL of venom. Comparative analysis of the identified proteins showed 893 proteins identified in common to all conditions, 949 proteins in common between the control group and 0.63 μg/mL venom treatment, 912 proteins were in common between control group and 2.5 μg/mL venom treatment, and 915 proteins were in common between the 0.63 μg/mL and 2.5 μg/mL venom treatments (Figure 2a, Table S1a). We also observed 38 exclusive proteins in the control group, 21 proteins in 0.63 μg/mL venom treatment, and 44 proteins exclusive in the 2.5 μg/mL venom treatment (Figure 2b, Table S1b).
