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Triple-negative breast cancer (TNBC) is aggressive, leading to poorer outcomes. Chemokines have chemoattractive potential for cancer metastasis. We investigated the signature of chemokine network between TNBC and non-TNBC cells followed by underlining mechanisms on enhanced proinflammatory chemokines in TNBC. Analysis from microarray dataset revealed that basal-like BC subtype representing TNBC expressed dominantly proinflammatory chemokines, such as CXCL1 and 8, compared to non-TNBC. Chemokine PCR array confirmed the dominant proinflammatory chemokines in TNBC cells. As a driving factor for proinflammatory chemokines in TNBC cells, we checked expression profiles for epidermal growth factor receptor (EGFR) family and its downstream signaling. TNBC cells showed higher expression levels of EGFR and phosphorylated Akt compared to non-TNBC cells. In addition, EGF enhanced the proinflammatory chemokines in TNBC cells. Knockdown of Akt reduced the CXCL2 promoter activity, while overexpression of Akt enhanced the activity. MKK2206, an Akt inhibitor, abrogated the CXCL2 promoter activity, but targeting Erk using inhibitor and knockdown did not reduce the activity. As a driving factor for EGFR-mediated Akt activation in TNBC cells, we found transforming growth factor alpha (TGFα) among ligands of EGFR family. MK2206 decreased the TGFα promoter activity, while overexpression of Akt significantly increased the activity in TNBC cells. MK2206 abrogated TGFα protein released by TNBC cells. MK2206 downregulated CXCL2 mRNA, while TGFα upregulated the CXCL2 expression. Taken together, higher expression of proinflammatory chemokines in TNBC involves TGFα-EGFR-Akt axis, probably contributing to the inflammatory burden followed by promoted cancer progression and higher mortality in TNBC. Citation Format: Rosa Mistica Coles Ignacio, Carla Gibbs, Eunsook Lee, Deok-Soo Son. Involvement of TGFa-EGFR-Akt axis on enhanced proinflammatory chemokines in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5073.

Obesity has become a global epidemic and causes a chronic low-grade inflammation. This poses a large health burden because excess adiposity can lead to chronic diseases such as type 2 diabetes, cardiovascular disease and some cancers. Obese individuals get higher incidence, progression and mortality of cancers compared to lean ones. Particularly, breast cancer (BC) in women is closely associated with obesity. Despite an epidemiological link between obesity and low cancer survival rates, little is known about the molecular mechanisms by which obesity promotes BC progression. Obesity-derived chronic low-grade inflammation involves alteration of a chemokine network that may contribute to the cancer progression and metastasis. Herein, we proposed the novel concept that the chemokine network between obesity and BC builds an inflammatory burden via proinflammatory chemokines to promote cancer progression. We employed mesenchymal BC cell PY8119 and epithelial-like BC PY230 for triple negative BC (TNBC) cell model, and mouse 3T3-L1 preadipocyte and adipocyte conditioned media (CM) to mimic lean and obese conditions in vitro. We examined the profiles of chemokine signature of PY8119 and PY230 treated with preadipocytes and adipocytes CM using PCR array. Both preadipocytes and adipocytes CM-treated PY8119 and PY230 cells absent or low levels in chemokine receptors. On the other hand, the chemokines CCL2, 5, 7 and CXCL10 showed higher expression in both preadipocyte and adipocyte CM-treated PY8119. Interestingly, adipocyte CM-treated PY8119 cells dominantly expressed CXCL1-3 compared to preadipocyte CM-treated cells. In addition, CCL2, 5, 7, 20, and CXCL1, 5, 10 were highly expressed in both preadipocyte and adipocyte CM-treated PY230 cells. Moreover, CXCL2 and 3 were significantly induced in PY230 cells after treatment with adipocyte CM compared to preadipocyte CM. Taken together, the results indicate that dominant chemokines CXCL1-3 expressed in adipocyte CM-treated TNBC cells promote a pro-tumor inflammatory network. Hence, these proinflammatory microenvironment augmented by adipocytes might contribute to TNBC progression. Citation Format: Rosa Mistica Coles Ignacio, Hyeongjwa Choi, Carla Gibbs, Eunsook Lee, Samuel Adunyah, Deok-Soo Son. Involvement of proinflammatory chemokine network between adipocytes and triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 950. doi:10.1158/1538-7445.AM2017-950

Breast cancer (BC) is the most frequent tumor in women worldwide. Although its mortality has significantly decreased owing to advanced therapies, triple negative breast cancer (TNBC) is still difficult to treat because of lack of estrogen receptor, progesterone receptor and HER-2. TNBC accounts for 12-24% of total BC and contributes to the aggressiveness and poorer outcomes. The risk of BC increases significantly in obese women. Obesity is also associated with the worse clinical prognosis of BC. But the underlying mechanisms between obesity and BC, particularly TNBC, remain unclear. Therefore, we compare the molecular mechanisms by which human adipocyte conditioned media (CM) affect TNBC cells (BT549) and non-TNBC cells (MCF7A). Adipocyte CM had no effect on the proliferation of both TNBC and non-TNBC cells. However, adipocyte CM enhanced significantly migration in TNBC cells compared to non-TNBC cells. Next, we examined the signaling pathway by which adipocyte CM promote migration of TNBC cell. AKT and ERK were activated in both TNBC cells and non-TNBC cells. However, phospho-STAT3 was significantly increased in TNBC cells. Also, N-cadherin, a marker for epithelial to mesenchymal transition (EMT), was increased at the late time point in TNBC cells. Furthermore, CXCR7 was specifically increased in TNBC cells after treatment with adipocyte CM using a PCR array. CXCR7 is chemoattractive to CXCL12 which is highly expressed in the lung, the bone marrow, and the liver, common sites of BC metastasis. Taken together, the results indicate that adipocyte CM may promote metastasis of TNBC cells through the CXCL12-CXCR7 axis by activating STAT3. Citation Format: Hyeongjwa Choi, Rosa Mistica C. Ignacio, Carla R. Gibbs, Eunsook Lee, Samuel E. Adunyah, Deok-Soo Son. Involvement of CXCL12-CXCR7 axis in adipocyte-induced TNBC metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2933. doi:10.1158/1538-7445.AM2017-2933

Objective: Triple-negative breast cancer (TNBC) accounts for 12-24% of total breast cancer, and contributes to the more aggressive, therapy-resistant and poorer outcomes. Our analysis based on The Cancer Genome Atlas (TCGA) indicated that basal-like BC subtype representing TNBC has enriched expression profiles for epidermal growth factor receptor 1 (EGFR) and transforming growth factor alpha (TGFá) compared to other subtypes. In addition, TNBC has a higher proinflammatory index compared to non-TNBC. Here we report that the proinflammatory chemokines such as CXCL1-3 and 8 are highly expressed in human TNBC cells and might be potentiated by TGFá-EGFR axis that contributes to cancer progression of TNBC. Methods: To gauge the role of TGFá-EGFR axis as a proinflammatory driver in TNBC cells, we first checked the expression profiles for EGFR family such as EGFR, HER2, ErbB3, and ErbB4 between TNBC (MCF10A, MB468, MB231, and BT549) and non-TNBC cells (MCF7, T47D). In addition, the expression levels of downstream signaling for EGFR (Akt/Erk) were measured by western blot. To dissect the role of TGFá-EGFR axis in enhancing proinflammatory index in TNBC cells, we utilized a more comprehensive study of the chemokines and chemokine receptors using human chemokine PCR array. Finally, to further confirm the role of TGFá-EGFR axis in inflammatory burden and cancer progression in TNBC, we used EGFR inhibitor and its downstream targets. Results: TNBC cells expressed more proinflammatory chemokines such as CXCL1-3 and 8 compared to non-TNBC cells. TNBC cells (MB468, MB231, and BT549) showed higher expression of EGFR which led to higher Akt activation as compared to non-TNBC cells. However, Erk is only activated in MB231. To dissect the involvement of Akt, expression of Akt isoforms in TNBC cells was accessed and Akt1 is the predominant isoform expressed in TNBC cells. To further assess the involvement of Akt1 in proinflammatory burden in TNBC cells, we used a commercial siRNA of Akt1 to knockdown Akt1. Knockdown of Akt1 significantly reduced the CXCL2 promoter activity. In addition, afatinib (an EGFR inhibitor) and MK2206 (an Akt inhibitor) significantly reduced the CXCL2 promoter activity. Conclusion: Thus, higher expression of proinflammatory chemokines CXCL1-3, and 8, via TGFá-EGFR axis-activated Akt, contributes to the inflammatory burden, probably promoting cancer progression, thereby followed by the overall high mortality in TNBC compared to non-TNBC. Citation Format: Rosa Mistica C. Ignacio, Carla Gibbs, Eun-Sook Lee, Deok-Soo Son. Involvement of proinflammatory chemokines in triple-negative breast cancer (TNBC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 726.