Compressive stress-mediated p38 activation required for ER alpha plus phenotype in breast cancer

Breast cancer is now globally the most frequent cancer and leading cause of women's death. Two thirds of breast cancers express the luminal estrogen receptor-positive (ER alpha + ) phenotype that is initially responsive to antihormonal therapies, but drug resistance emerges. A major barrier to the understanding of the ER alpha-pathway biology and therapeutic discoveries is the restricted repertoire of luminal ER alpha + breast cancer models. The ER alpha + phenotype is not stable in cultured cells for reasons not fully understood. We examine 400 patient-derived breast epithelial and breast cancer explant cultures (PDECs) grown in various three-dimensional matrix scaffolds, finding that ER alpha is primarily regulated by the matrix stiffness. Matrix stiffness upregulates the ER alpha signaling via stress-mediated p38 activation and H3K27me3-mediated epigenetic regulation. The finding that the matrix stiffness is a central cue to the ER alpha phenotype reveals a mechanobiological component in breast tissue hormonal signaling and enables the development of novel therapeutic interventions. Subject terms: ER-positive (ER + ), breast cancer, ex vivo model, preclinical model, PDEC, stiffness, p38 SAPK. Reliable luminal estrogen receptor (ER alpha+) breast cancer models are limited. Here, the authors use patient derived breast epithelial and breast cancer explant cultures grown in several extracellular matrix scaffolds and show that ER alpha expression is regulated by matrix stiffness via stress-mediated p38 activation and H3K27me3-mediated epigenetic regulation.Peer reviewe

Compressive stress-mediated p38 activation required for ERα + phenotype in breast cancer

Breast cancer is now globally the most frequent cancer and leading cause of women's death. Two thirds of breast cancers express the luminal estrogen receptor-positive (ER alpha + ) phenotype that is initially responsive to antihormonal therapies, but drug resistance emerges. A major barrier to the understanding of the ER alpha-pathway biology and therapeutic discoveries is the restricted repertoire of luminal ER alpha + breast cancer models. The ER alpha + phenotype is not stable in cultured cells for reasons not fully understood. We examine 400 patient-derived breast epithelial and breast cancer explant cultures (PDECs) grown in various three-dimensional matrix scaffolds, finding that ER alpha is primarily regulated by the matrix stiffness. Matrix stiffness upregulates the ER alpha signaling via stress-mediated p38 activation and H3K27me3-mediated epigenetic regulation. The finding that the matrix stiffness is a central cue to the ER alpha phenotype reveals a mechanobiological component in breast tissue hormonal signaling and enables the development of novel therapeutic interventions. Subject terms: ER-positive (ER + ), breast cancer, ex vivo model, preclinical model, PDEC, stiffness, p38 SAPK.Reliable luminal estrogen receptor (ER alpha+) breast cancer models are limited. Here, the authors use patient derived breast epithelial and breast cancer explant cultures grown in several extracellular matrix scaffolds and show that ER alpha expression is regulated by matrix stiffness via stress-mediated p38 activation and H3K27me3-mediated epigenetic regulation.</p

Rintasyövän mikroympäristön tiukkuuden vaikutus syövän immuunivasteeseen

Rintasyöpä on naisten yleisin syöpä ja toisiksi yleisin syöpään liittyvä kuolinsyy, aiheuttaen noin 900 vuosittaista kuolemaa Suomessa. Suurin osa rintasyöpään liittyvistä kuolemista johtuu metastaaseista, jotka ovat resistenttejä sekä hormonaalisille terapioille, että useille kemoterapioille. Pehmeän mikroympäristön on useissa tutkimuksissa näytetty erilaistavan primaaria rintasyöpää huonommin erilaistuneeksi ja aktivoivan useita molekulaarisia reittejä, jotka aiheuttavat resistenssiä kemoterapioille ja hormonaalisille terapioille. Toisaalta kasvaimet ovat perinteisesti mielletty tiukoiksi ja kasvainympäristön tiukkuuden on todettu aikaisemmissa tutkimuksissa promotoivan metastaaseja, sekä kasvaimen agressivisempaa kasvutapaa. Tässä tutkimuksessa tutkimme miten matriksin tiukkuus vaikuttaa rintasyövän immuunivasteeseen. Käytimme mallina tutkimusryhmässämme kehitettyä PDEC-mallia, joka säilyttää elossa sekä kasvainsolut, että kasvaimen residentit immuunisolut. Havaitsimme, että mallissamme oleva kasvainsolukko aiheuttaa parakriinisellä signaloinnilla immuunisuppressivisen mikroympäristön, jos kasvainsolut on sijoitettu pehmeään mikroympäristöön. Pehmeässä mikroympäristössä kasvaneissa kasvaimissa oli huomattavasti enemmän perinteisesti immuunisuppressivisiksi miellettyjä sytokiineja, kun taas tulehdukseen liittyvien sytokiinien ekspressio oli korkeampi tiukemmassa mikroympäristössä. Havaitsimme myös, että kasvainsolukko aiheutti pehmeässä mikroympäristössä parakriinisia muutoksia immuunisolujen fenotyypissä, eilaistaen makrofageja kohti M2-alatyyppiä ja aiheuttaen sytotoksisten CD8+ solujen kuoleman. Estämällä targetoiduilla terapioilla kasvaimesta erittyvien parakriinisten immuunisuppressivisten tuotannon, pystyimme estämään makrofagien erilaistumisen mallissa ja siten vaikuttamaan havaittuun immuunisuppressioon. Tutkimustuloksemme tuovat uutta tietoa miten mikroympäristön tiukkuus vaikuttaa kasvaimen immuunivasteesen. Esimerkiksi metastasoivat syöpäsolut kohtaavat rasvakudokseen siirtyessään huomattavasti pehmeämmän mikroympäristön, mikä kliinisesti matkii mallissa havaitsemaamme tilannetta.Breast cancer is the most common cancer among women and the second most leading cause of cancer related deaths in Finland, accounting for over 900 deaths annually. The majority of breast cancer related fatalities are caused by therapy resistance leading to metastasis. Several studies have established the role of soft matrix in promoting the undifferentiated and oestrogen receptor negative phenotype of breast cancer cells, which are also resistant to a variety of commonly used chemotherapeutics and hormonal therapies. On the contrary, traditionally tumor tissue is has been considered as extremely stiff, and the stiffness of the tumor microenvironment has been established to promote the growth and the metastasis of several cancer types. In this study we adressed how microenvironmental stiffness alters the phenotype of antitumor immune response by culturing primary breast tumor tissue in PDEC-model. We established, that the soft microenvironment promotes immune suppression in primary breast cancer by upregulating the production of immuno suppressive cytokines and polarizating macrophages towards more M2 or alternatively activated ones. Moreover, in the soft microenvironment, cytotoxic CD8+ T-cells are lost. These effects are created by tumor tissue derived paracrine signaling and by inhibiting these signals with small molecules we were able to reverse the observed immunosuppression. These results provide us a novel information how microenvironmental stiffness alters the phenotype of the antitumor immune respons

Fibrin Stiffness Regulates Phenotypic Plasticity of Metastatic Breast Cancer Cells

The extracellular matrix (ECM)-regulated phenotypic plasticity is crucial for metastatic progression of triple negative breast cancer (TNBC). While ECM faithful cell-based models are available for in situ and invasive tumors, such as cell aggregate cultures in reconstituted basement membrane and in collagenous gels, there are no ECM faithful models for metastatic circulating tumor cells (CTCs). Such models are essential to represent the stage of metastasis where clinical relevance and therapeutic opportunities are significant. Here, CTC-like DU4475 TNBC cells are cultured in mechanically tunable 3D fibrin hydrogels. This is motivated, as in circulation fibrin aids CTC survival by forming a protective coating reducing shear stress and immune cell-mediated cytotoxicity and promotes several stages of late metastatic processes at the interface between circulation and tissue. This work shows that fibrin hydrogels support DU4475 cell growth, resulting in spheroid formation. Furthermore, increasing fibrin stiffness from 57 to 175 Pa leads to highly motile, actin and tubulin containing cellular protrusions, which are associated with specific cell morphology and gene expression patterns that markedly differ from basement membrane or suspension cultures. Thus, mechanically tunable fibrin gels reveal specific matrix-based regulation of TNBC cell phenotype and offer scaffolds for CTC-like cells with better mechano-biological properties than liquid.Peer reviewe

Respiratory complex I regulates dendritic cell maturation in explant model of human tumor immune microenvironment.

BACKGROUND: Combining cytotoxic chemotherapy or novel anticancer drugs with T-cell modulators holds great promise in treating advanced cancers. However, the response varies depending on the tumor immune microenvironment (TIME). Therefore, there is a clear need for pharmacologically tractable models of the TIME to dissect its influence on mono- and combination treatment response at the individual level. METHODS: Here we establish a patient-derived explant culture (PDEC) model of breast cancer, which retains the immune contexture of the primary tumor, recapitulating cytokine profiles and CD8+T cell cytotoxic activity. RESULTS: We explored the immunomodulatory action of a synthetic lethal BCL2 inhibitor venetoclax+metformin drug combination ex vivo, discovering metformin cannot overcome the lymphocyte-depleting action of venetoclax. Instead, metformin promotes dendritic cell maturation through inhibition of mitochondrial complex I, increasing their capacity to co-stimulate CD4+T cells and thus facilitating antitumor immunity. CONCLUSIONS: Our results establish PDECs as a feasible model to identify immunomodulatory functions of anticancer drugs in the context of patient-specific TIME