TNFAIP2 promotes TNBC DNA damage drug resistance

(A-E) Stable TNFAIP2 overexpression in HCC1806 and HCC1937 cells significantly increased cell viability in the presence of EPI (0-1.6 μM) or BMN (0-40 μM) treatment for 48h, as measured by the SRB assay. TNFAIP2 protein expression was detected by WB.

(F-J) Stable TNFAIP2 knockdown in HCC1806 and HCC1937 cells significantly decreased cell viability in the presence of EPI (0-1.6 μM) or BMN (0-40 μM) treatment for 48h, as measured by the SRB assay. TNFAIP2 protein expression was detected by WB.

(K) TNFAIP2 promoted DNA damage repair in the presence of EPI and BMN. HCC1806 and HCC1937 cells stably overexpressing TNFAIP2 were treated with 400 or 800 nM EPI for 48h and 10 μM BMN for 24h, respectively. TNFAIP2, γH2AX, and PARP protein expression was detected by WB.

(L) TNFAIP2 knockdown increased DNA damage in the presence of EPI and BMN. Stable TNFAIP2 knockdown cells were treated with 400 or 800 nM EPI for 24 or 48h and 2.5 μM BMN for 24h. TNFAIP2, γH2AX, and PARP protein expression was detected by WB.

TNFAIP2 confers TNBC drug resistance in vivo

(A-F) TNFAIP2 knockdown increased the sensitivity of HCC1806 breast cancer cells to EPI and BMN in vivo. HCC1806 cells with stable TNFAIP2 knockdown were transplanted into the fat pad of 7-week-old female nude mice. When the average tumor size reached approximately 50 mm3 after inoculation, mice in each group were randomly divided into two subgroups (n=4/group) to receive EPI (2.5 mg/kg), BMN (1 mg/kg) or vehicle control for 23 or 29 days (A-B). Tumor size was measured twice a week (C-D), and tumor masses were collected and weighed at the end of the experiments (E-F). *: P<0.05, **: P<0.01, t-test.

TNFAIP2 promotes TNBC drug resistance and DNA damage repair via Rac1

(A-F) Rac1 knockdown abolished TNFAIP2-induced TNBC resistance to EPI and BMN. HCC1806 (A-C) and HCC1937 (D-F) cells with stable TNFAIP2 overexpression were transfected with Rac1 or control siRNA, followed by treatment with EPI (0-1600 nM) and BMN (0-40 μM) for 48 or 72 h, respectively. Cell viability was measured by the SRB assay. Protein expression levels were analyzed by WB.

(G-J) Rac1 depletion abolished TNFAIP2-induced DNA damage decrease in response to EPI and BMN. HCC1806 (G-H) and HCC1937 (I-J) cells with stable TNFAIP2 overexpression were transfected with Rac1 or control siRNA, followed by treatment with EPI (400 or 800 nM) and BMN (10 μM) for 24h, respectively. Protein expression levels were analyzed by WB.

IQGAP1 mediates Rac1 activation by TNFAIP2 and promotes TNBC drug resistance

(A) The IP-MS result of TNFAIP2 in HCC1806 cells.

(B) Endogenous TNFAIP2 interacts with IQGAP1 in HCC1806 cells. Endogenous TNFAIP2 protein was immunoprecipitated using ananti-IQGAP1 antibody. Immunoglobulin (Ig)G served as the negative control. Endogenous TNFAIP2 was detected by WB.

(C-G) IQGAP1 knockdown in HCC1806 and HCC1937 cells significantly decreased cell viability in the presence of EPI (0-1600 nM) and BMN (0-40 μM), as measured by the SRB assay. IQGAP1 protein expression was detected by WB.

(H) IQGAP1 knockdown in HCC1806 and HCC1937 cells increased DNA damage of EPI and BMN. HCC1806 and HCC1937 cells with IQGAP1 knockdown were treated with 800 nM EPI for 24h and 10 μM BMN for24h, respectively. ITGB4, γH2AX, and PARP protein expression was detected by WB.

(I-K) IQGAP1 knockdown abolished TNFAIP2-confered resistance to EPI and BMN. HCC1806 cells with stable TNFAIP2 overexpression were transfected with IQGAP1 or control siRNA, followed by treatment with EPI (0-1600 nM) and BMN (0-40 μM) for 48 or 72 h, respectively. Cell viability was measured by the SRB assay. IQGAP1 protein expression was detected by WB.

(L) IQGAP1 knockdown abolished TNFAIP2-confered resistance to EPI and BMN. HCC1806 and HCC1937 cells with stable TNFAIP2 overexpression were transfected with IQGAP1 or control siRNA, followed by treatment with EPI (800 nM) and BMN (10 μM) for 24h, respectively. Protein expression levels were analyzed by WB.

(M) IQGAP1 knockdown abolished TNFAIP2-confered Rac1 activation. HCC1806 and HCC1937 cells with stable TNFAIP2 overexpression were transfected with IQGAP1 or control siRNA. GTP-Rac1 levels were assessed using PAK-PBD beads.

ITGB4 interacts with TNFAIP2 and promotes TNBC drug resistance and DNA damage repair

(A) TNFAIP2 interacts with ITGB4.HCC1806 cells with stable TNFAIP2 overexpression were collected from flag-tagged TNFAIP2 cell lysates for immunoprecipitation assays using Flag-M2 beads, and ITGB4 was detected by WB.

(B) Endogenous TNFAIP2 interacts with ITGB4 in HCC1806 cells. Endogenous TNFAIP2 protein was immunoprecipitated using an anti-TNFAIP2 antibody. IgG served as the negative control. Endogenous ITGB4 was detected by WB.

(C) Endogenous ITGB4 interacts with TNFAIP2 in HCC1806 cells. Endogenous ITGB4 protein was immunoprecipitated using an anti-ITGB4 antibody. IgG served as the negative control. Endogenous TNFAIP2 was detected by WB.

(D-I) ITGB4 knockdown in HCC1806 and HCC1937 cells significantly decreased cell viability in the presence of EPI (0-800 nM) and BMN (0-40 μM), as measured by the SRB assay. ITGB4 protein expression was detected by WB.

(J-N) ITGB4 depletion promotes HCC1806 breast cancer cell sensitivity to EPI and BMN treatment in vivo. HCC1806 cells with stable ITGB4 knockdown were transplanted into the fat pad of 7-week-old female nude mice. When the average tumor size reached approximately 50 mm3 after inoculation, the mice in each group were randomly divided into two subgroups (n=4/group) to receive EPI (2.5 mg/kg), BMN (1 mg/kg) or vehicle control for 22 days(J). Tumor masses were collected and weighed at the end of the experiments(K), and tumor size was measured twice a week (L-N).*: P<0.05, **: P<0.01, t-test.

(O) ITGB4 knockdown increased DNA damage of EPI and BMN. HCC1806 and HCC1937 cells with ITGB4 knockdown were treated with 400 nM EPI for 24h and 5 μM BMN for 24h, respectively. ITGB4, γH2AX, and PARP protein expression was detected by WB.

ITGB4 activates Rac1 through TNFAIP2 and IQGAP1

(A) Overexpression of ITGB4 increased GTP-Rac1 levels in HCC1806 and HCC1937 cells. GTP-Rac1 were assessed using PAK-PBD beads.

(B) Knockdown of ITGB4 by shRNA decreased GTP-Rac1 levels in HCC1806 and HCC1937 cells.

(C-D) ITGB4 activates Rac1 through TNFAIP2. HCC1806 (C) and HCC1937 (D) cells with stable ITGB4 overexpression were transfected with TNFAIP2 or control siRNA.

(E-F) ITGB4 activates Rac1 through IQGAP1.HCC1806 (E) and HCC1937 (F) cells with stable ITGB4 overexpression were transfected with IQGAP1 or control siRNA.

ITGB4 promotes TNBC drug resistance via TNFAIP2/IQGAP1/Rac1

(A-C) ITGB4 promotes TNBC drug resistance through TNFAIP2. TNFAIP2 knockdown abolished ITGB4-induced resistance to EPI and BMN. HCC1806 cells with stable ITGB4 overexpression were transfected with TNFAIP2 or control siRNA, followed by treatment with EPI (0-400 nM) and BMN (0-30 μM) for 48 or 72 h, respectively. Cell viability was measured by the SRB assay. Protein expression levels were analyzed by WB.

(D-F) ITGB4 promotes TNBC drug resistance through IQGAP1. HCC1806 cells with stable ITGB4 overexpression were transfected with IQGAP1 or control siRNA, followed by treatment with EPI (0-800 nM) and BMN (0-40 μM) for 48 or 72 h, respectively. Cell viability was measured by the SRB assay. Protein expression levels were analyzed by WB.

(G-I) ITGB4 promotes TNBC drug resistance through Rac1. HCC1806 cells with stable ITGB4 overexpression were transfected with Rac1 or control siRNA, followed by treatment with EPI (0-400 nM) and BMN (0-40 μM) for 48 or 72 h, respectively. Cell viability was measured by the SRB assay. Protein expression levels were analyzed by WB.

(J) ITGB4 promotes DNA damage repair through TNFAIP2. HCC1806 cells with stable ITGB4 overexpression were transfected with TNFAIP2 or control siRNA, followed by treatment with EPI (400 nM) and BMN (5 μM) for 24h. Protein expression levels were analyzed by WB.

(K) ITGB4 promotes DNA damage repair through IQGAP1. HCC1806 cells with stable ITGB4 overexpression were transfected with IQGAP1 or control siRNA, followed by treatment with EPI (400 nM) and BMN (5 μM) for 24h. Protein expression levels were analyzed by WB.

(L) ITGB4 promotes DNA damage repair through Rac1. HCC1806 cells with stable ITGB4 overexpression were transfected with Rac1 or control siRNA, followed by treatment with EPI (400 nM) and BMN (5 μM) for 24h. Protein expression levels were analyzed by WB.

TNFAIP2 expression levels positively correlated with ITGB4 in TNBC tissues

Representative IHC images of TNFAIP2 and ITGB4 protein expression in breast cancer tissues are shown. The final expression assessment was performed by combining the two scores (0–2=low, 6–7=high). A and B indicate low scores, C and D indicate high scores, and Figure E is the work model of this paper.