Progression of Luminal Breast Tumors Is Promoted by Ménage à Trois between the Inflammatory Cytokine TNFαand the Hormonal and Growth-Supporting Arms of the Tumor Microenvironment

Abstract

Breast cancer progression is strongly linked to inflammatory processes, aggravating disease course. The impacts of the inflammatory cytokine TNFα on breast malignancy are not fully substantiated, and they may be affected by cooperativity between TNFα and other protumoral mediators. Here, we show that together with representatives of other important arms of the tumor microenvironment, estrogen (hormonal) and EGF (growth-supporting), TNFα potently induced metastasis-related properties and functions in luminal breast tumor cells, representing the most common type of breast cancer. Jointly, TNFα + Estrogen + EGF had a stronger effect on breast cancer cells than each element alone, leading to the following: (1) extensive cell spreading and formation of FAK/paxillin-enriched cellular protrusions; (2) elevated proportion of tumor cells coexpressing high levels of CD44 and β1 and VLA6; (3) EMT and cell migration; (4) resistance to chemotherapy; (5) release of protumoral factors (CXCL8, CCL2, MMPs). Importantly, the tumor cells used in this study are known to be nonmetastatic under all conditions; nevertheless, they have acquired high metastasizing abilities in vivo in mice, following a brief stimulation by TNFα + Estrogen + EGF. These dramatic findings indicate that TNFα can turn into a strong prometastatic factor, suggesting a paradigm shift in which clinically approved inhibitors of TNFα would be applied in breast cancer therapy.

Microenvironmental networks promote tumor heterogeneity and enrich for metastatic cancer stem-like cells in Luminal-A breast tumor cells

“…MCF-7 and T47D cells were found to adhere well to the needs of this study, as they are able to respond to TME Stimulation, composed of estrogen+TNFα+EGF [40, 41], by: (1) Expressing ER and responding to estrogen; (2) Expressing TNFα receptors and responding to TNFα; (3) Responding to EGF, through the expression of different EGF receptors [40, 48–51]. …”

“…qRT-PCR analyses were performed as previously described [40]. Dissociation curves for each primer set indicated a single product, and no-template controls were negative.…”

High-fat Diet Enhances Mammary Tumorigenesis and Pulmonary Metastasis and Alters Inflammatory and Angiogenic Profiles in MMTV-PyMT Mice

“…MCP1 and PAI1, are found in plasma and mammary tumors from MMTV-PyMT mice (26)(27)(28). Expression of proinflammatory cytokines MCP1 (26), PAI1 (29,30), TNFα (31), and resistin (32) are elevated in invasive breast cancer. In luminal B breast cancer, increased the expression of these cytokines is associated with poor prognosis and lower overall survival (26,33,34).…”

Chemokine axes in breast cancer: factors of the tumor microenvironment reshape the CCR7-driven metastatic spread of luminal-A breast tumors

“…In a previous study, we have shown that the TME of primary breast tumors, represented by the estrogen + TNF-a + EGF stimulus (named "TME stimulation"), is a strong driver of metastasis in luminal-A breast tumor cells [53]. The combined stimulus of estrogen + TNF-a + EGF was much more effective than each factor alone in inducing metastasis-related functions in luminal-A breast tumor cells.…”

“…The combined stimulus of estrogen + TNF-a + EGF was much more effective than each factor alone in inducing metastasis-related functions in luminal-A breast tumor cells. These cells responded to this combined stimulus by increased release of angiogenic and proinflammatory factors, as well as matrix metalloproteinases; furthermore, they have exhibited an increased spreading and scattering phenotype, accompanied by formation of robust cellular protrusions [53]. In the present study, with the focus on the CCR7-CCL21 axis, we demonstrate that the same TME stimulus actually imposes constraints on the CCR7-mediated process of CCL21-induced tumor cell migration and of LN metastasis and shifts the metastatic pattern of luminal-A tumor cells toward the more aggressive pattern of metastasis in bones that are the prime metastatic sites in luminal-A breast cancer patients [23,26,27].…”