Journal: Heliyon

Article Title: The Nrf2 inhibitor brusatol synergistically enhances the cytotoxic effect of lapatinib in HER2-positive cancers

doi: 10.1016/j.heliyon.2022.e10410

Figure Lengend Snippet: Brusatol in combination with lapatinib synergistically inhibited the growth of HER2-overexpressed SK-BR-3, SK-OV-3 and AU565 cells (A) SK-BR-3, SK-OV-3 and AU565 cell lines were treated with brusatol, lapatinib or brusatol plus lapatinib in a dose range for 48 h. CCK-8 assays were used to measure the cell viability. Points, mean of 3 independent CCK-8 assays; Bars, SD. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001 (B) The synergistic effect of lapatinib in combination with brusatol was evaluated on the growth of SK-BR-3, SK-OV-3 and AU565 cell line. Combination index (CI) values were calculated using the Chou-Talalay method. Drug synergy, addition, and antagonism are defined by CI values less than 1.0, equal to 1.0, or greater than 1.0, respectively.

Article Snippet: The antibodies were utilized as following: Nrf2 (1:1000; cat. no. 16396-1-AP; ProteinTech Group, Inc.), HO-1 (1:1000; cat. no. 10701-1-AP; ProteinTech Group, Inc.), HER2 (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-HER2 (Tyr 1221/1222) (1:1,000; cat. no. 2243; Cell Signaling Technology, Inc.), EGFR (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-EGFR (Tyr1068) (1:1,000; cat. no. 2234; Cell Signaling Technology, Inc.), AKT (1:1,000; cat. no. 10176-2-AP; ProteinTech Group, Inc.), p-AKT (Ser 473) (1:2,000; cat. no. 4060; Cell Signaling Technology, Inc.), ERK1/2 (1:2,000; cat. no. 9102; Cell Signaling Technology, Inc.), p-ERK1/2 (Thr202/Tyr204) (1:2,000; cat. no. 8544; Cell Signaling Technology, Inc.), β-actin (1:5,000; cat. no. ab179467; Abcam) and horseradish peroxidase-conjugated goat anti-mouse/rabbit secondary antibodies (1:5,000; cat. no. SA00001-1 or SA00001-2; ProteinTech Group, Inc.).

Techniques: CCK-8 Assay

Journal: Heliyon

Article Title: The Nrf2 inhibitor brusatol synergistically enhances the cytotoxic effect of lapatinib in HER2-positive cancers

doi: 10.1016/j.heliyon.2022.e10410

Figure Lengend Snippet: Lapatinib plus brusatol abrogate the activation of Nrf2/HO-1 and EGFR/HER2-AKT/ERK1/2 pathways (A and B) SK-BR-3 and SK-OV-3 cells were treated with lapatinib or brusatol alone, or their combination for 24 h. The changes in Nrf2/HO-1 and EGFR/HER2-AKT/ERK1/2 signaling pathways were monitored by Western Blotting (C and D) Densitometric analysis was performed on the Western Blotting. The levels of Nrf2, HO-1, p-HER2, p-EGFR, p-AKT and p-ERK1/2 were quantified by using the software Image J. The data are expressed as the mean ± SD of three independent experiments. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. The original blots were provided in supplementary data as Supplementary Figure S4.

Article Snippet: The antibodies were utilized as following: Nrf2 (1:1000; cat. no. 16396-1-AP; ProteinTech Group, Inc.), HO-1 (1:1000; cat. no. 10701-1-AP; ProteinTech Group, Inc.), HER2 (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-HER2 (Tyr 1221/1222) (1:1,000; cat. no. 2243; Cell Signaling Technology, Inc.), EGFR (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-EGFR (Tyr1068) (1:1,000; cat. no. 2234; Cell Signaling Technology, Inc.), AKT (1:1,000; cat. no. 10176-2-AP; ProteinTech Group, Inc.), p-AKT (Ser 473) (1:2,000; cat. no. 4060; Cell Signaling Technology, Inc.), ERK1/2 (1:2,000; cat. no. 9102; Cell Signaling Technology, Inc.), p-ERK1/2 (Thr202/Tyr204) (1:2,000; cat. no. 8544; Cell Signaling Technology, Inc.), β-actin (1:5,000; cat. no. ab179467; Abcam) and horseradish peroxidase-conjugated goat anti-mouse/rabbit secondary antibodies (1:5,000; cat. no. SA00001-1 or SA00001-2; ProteinTech Group, Inc.).

Techniques: Activation Assay, Protein-Protein interactions, Western Blot, Software

Journal: Heliyon

Article Title: The Nrf2 inhibitor brusatol synergistically enhances the cytotoxic effect of lapatinib in HER2-positive cancers

doi: 10.1016/j.heliyon.2022.e10410

Figure Lengend Snippet: Nrf2 knockdown repressed the activation of HER2 signaling pathway and sensitizes SK-OV-3 cells to lapatinib treatment (A) Effect of Nrf2 knockdown on the expression of HO-1, p-HER2, p-AKT, and p-ERK1/2 were determined after treatment with Nrf2 siRNA or scramble siRNA for 36 h (B) Effect of Nrf2 knockdown on the sensitivity to lapatinib. Cell viability was examined after lapatinib treatment for 36 h in Nrf2 siRNA or scramble siRNA-transfected cells. Cells were transfected with Nrf2 siRNA or scramble siRNA using Lipofectamine 3000 (Invitrogen) according to the supplier's instruction. Data show the mean ± SD (three independent experiments). ∗∗∗ p < 0.001. The original blots were provided in supplementary data as Supplementary Figure S5.

Article Snippet: The antibodies were utilized as following: Nrf2 (1:1000; cat. no. 16396-1-AP; ProteinTech Group, Inc.), HO-1 (1:1000; cat. no. 10701-1-AP; ProteinTech Group, Inc.), HER2 (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-HER2 (Tyr 1221/1222) (1:1,000; cat. no. 2243; Cell Signaling Technology, Inc.), EGFR (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-EGFR (Tyr1068) (1:1,000; cat. no. 2234; Cell Signaling Technology, Inc.), AKT (1:1,000; cat. no. 10176-2-AP; ProteinTech Group, Inc.), p-AKT (Ser 473) (1:2,000; cat. no. 4060; Cell Signaling Technology, Inc.), ERK1/2 (1:2,000; cat. no. 9102; Cell Signaling Technology, Inc.), p-ERK1/2 (Thr202/Tyr204) (1:2,000; cat. no. 8544; Cell Signaling Technology, Inc.), β-actin (1:5,000; cat. no. ab179467; Abcam) and horseradish peroxidase-conjugated goat anti-mouse/rabbit secondary antibodies (1:5,000; cat. no. SA00001-1 or SA00001-2; ProteinTech Group, Inc.).

Techniques: Knockdown, Activation Assay, Expressing, Transfection

Journal: Heliyon

Article Title: The Nrf2 inhibitor brusatol synergistically enhances the cytotoxic effect of lapatinib in HER2-positive cancers

doi: 10.1016/j.heliyon.2022.e10410

Figure Lengend Snippet: Proposed model of the molecular basis of synergistic interaction between lapatinb and brusatol. Brusatol, in combination with lapatinib, may exert synergistic effects in two ways: (a) combination therapy inhibits the phosphorylation of HER receptors including EGFR and HER2, limiting the activation of their downstream pathways including PI3K-AKT signaling and Ras/Raf/MAPK signaling. (b) combination therapy modulates cell redox homeostasis by decreasing Nrf2 level and preventing the accumulation of Nrf2 in the nucleus, interfering its binding to small Maf oncogene family proteins (Mafs) and antioxidant response elements (AREs) complex, causing the inhibition of antioxidant genes such as heme oxygenase 1 (HO-1) and superoxide dismutase (SOD), thereby resulting in ROS accumulation and cell death.

Article Snippet: The antibodies were utilized as following: Nrf2 (1:1000; cat. no. 16396-1-AP; ProteinTech Group, Inc.), HO-1 (1:1000; cat. no. 10701-1-AP; ProteinTech Group, Inc.), HER2 (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-HER2 (Tyr 1221/1222) (1:1,000; cat. no. 2243; Cell Signaling Technology, Inc.), EGFR (1:1,000; cat. no. 54359; Cell Signaling Technology, Inc.), phosphorylated (p)-EGFR (Tyr1068) (1:1,000; cat. no. 2234; Cell Signaling Technology, Inc.), AKT (1:1,000; cat. no. 10176-2-AP; ProteinTech Group, Inc.), p-AKT (Ser 473) (1:2,000; cat. no. 4060; Cell Signaling Technology, Inc.), ERK1/2 (1:2,000; cat. no. 9102; Cell Signaling Technology, Inc.), p-ERK1/2 (Thr202/Tyr204) (1:2,000; cat. no. 8544; Cell Signaling Technology, Inc.), β-actin (1:5,000; cat. no. ab179467; Abcam) and horseradish peroxidase-conjugated goat anti-mouse/rabbit secondary antibodies (1:5,000; cat. no. SA00001-1 or SA00001-2; ProteinTech Group, Inc.).

Techniques: Phospho-proteomics, Activation Assay, Binding Assay, Inhibition

Journal: The American journal of pathology

Article Title: The nonreceptor-type tyrosine phosphatase PTPN13 is a tumor suppressor gene in non-small cell lung cancer.

doi: 10.1016/j.ajpath.2011.11.038

Figure Lengend Snippet: Figure 8. PTPN13 negatively regulates tyrosine phosphorylation of HER2 and EGFR in NSCLC-derived cells in vitro and tumor growth in vivo. A: Immunoblot analysis of PTPN13, pHER2, HER2, pEGFR, EGFR, pAKT, AKT, pMAPK, and MAPK in lysates obtained from NCI-H292 cells and from the corresponding cells interfered with shRNA to PTPN13, treated with solvent or EGF for 15 minutes. ACTB, actin used for normalization. B: Immunostaining analysis of PTPN13, pHER2, and pEGFR in tumor xenografts generated by injection of NCI-H292 cells and from the corresponding cells interfered with shRNA to PTPN13 (original magnification, 40). In particular, pHER2 staining was detected in 50% 3% of NCI-H292 interfered with shRNA to PTPN13 compared with 20% 8% of pHER2-positive NCI-H292 cells, and pEGFR staining was detected in 35% 7% of NCI-H292 interfered with shRNA to PTPN13 compared with 10% 6% of pEGFR-positive NCI-H292 cells. C: Immunoblot analysis of PTPN13, pHER2, HER2, pMAPK, MAPK, pAKT, and AKT in lysates obtained from A549 cells transfected with PTPN13 and activated HER2.

Article Snippet: Antibodies used for immunostaining were selected according to previously published work and were from Cell Signaling Technology (Danvers, MA) [anti-pS473 (no. 9277), anti-AKT1 (no. 2938), antipEGFR (Y1068, no. 3777), anti-pMAPK (no. 4370)], AbCam (Cambridge, UK) [anti-PTPN13 (AC21)], and R&D Systems (Minneapolis, MN) [anti-pHER2 (Y1248, no. AF1768)].

Techniques: Phospho-proteomics, Derivative Assay, In Vitro, In Vivo, Western Blot, shRNA, Solvent, Immunostaining, Generated, Injection, Staining, Transfection