Lack of functional TSLP receptors mitigates Th2 polarization and the establishment and growth of 4T1 primary breast tumours but has different effects on tumour quantities in the lung and brain

The correlation between single nucleotide polymorphisms of the thymic stromal lymphopoietin receptor and breast cancer in a cohort of female patients in Saudi Arabia

The current study aimed to examine thymic stromal lymphopoietin receptor (TSLPR) genetic variation and breast cancer (BC) susceptibility in women in Saudi Arabia. Therefore, 127 blood samples from female patients diagnosed with BC and 116 blood samples from healthy female controls were studied using a genotyping assay to determine the association between three TSLPR single nucleotide polymorphisms (SNPs)-P196L, X201W, and A238V-and the risk of BC progression. In addition, gene expression was evaluated in 20 matching BC and normal tissues using immunohistochemistry. TSLPR protein levels were higher among BC patients than those with matching normal breast tissue. In addition, TSLPR SNP P196L was found to have a significant protective effect on BC progression (OR = 0.4427), although only the T allele for TSLPR P196L had this protective effect against BC progression in participants who were younger than 48 years old. In contrast, no association was found between the T allele and risk of BC in participants who were older than 48 years old, and the CT and TT genotypes were significantly associated with BC risk protection in the older group. The effects of the TT genotype and the T allele were closely associated with a decreased risk of BC in participants with estrogen receptors (ER+) and without them (ER-). Overall, the findings revealed a significant correlation between SNPs in the TSLPR genes and BC progression among women in Saudi Arabia.

Fine-Tuning the Tumour Microenvironment: Current Perspectives on the Mechanisms of Tumour Immunosuppression

Immunotherapy has revolutionised the treatment of cancers by harnessing the power of the immune system to eradicate malignant tissue. However, it is well recognised that some cancers are highly resistant to these therapies, which is in part attributed to the immunosuppressive landscape of the tumour microenvironment (TME). The contexture of the TME is highly heterogeneous and contains a complex architecture of immune, stromal, vascular and tumour cells in addition to acellular components such as the extracellular matrix. While understanding the dynamics of the TME has been instrumental in predicting durable responses to immunotherapy and developing new treatment strategies, recent evidence challenges the fundamental paradigms of how tumours can effectively subvert immunosurveillance. Here, we discuss the various immunosuppressive features of the TME and how fine-tuning these mechanisms, rather than ablating them completely, may result in a more comprehensive and balanced anti-tumour response.

Thymic Stromal Lymphopoietin and Cancer: Th2-Dependent and -Independent Mechanisms

The thymic stromal lymphopoietin (TSLP) is an IL-7-like cytokine originally cloned from a murine thymic stromal cell line, and subsequently a human homolog was identified using database search methods. Human TSLP is mostly expressed in epithelial cells, among which are keratinocytes as well as stromal cells such as fibroblasts and immune cells. Human TSLP was first described to activate myeloid dendritic cells, which prime naïve T helper cells to produce high concentrations of Th2 cytokines, thus representing a key cytokine in triggering dendritic cells-mediated allergic Th2 inflammation. TSLP and/or its receptor has been shown to be expressed in several tumor types, where TSLP expression is associated with functional activities that can be associated or not with the induction of a Th2-prone tumor microenvironment, i.e., Th2-dependent and Th2-independent mechanisms. These mechanisms involve tissue- and immune cell target-dependent tumor-promoting or tumor-suppressive functions in different or even the same tumor type. Here we report and discuss the Th2-dependent and Th2-independent roles of TSLP in cancer and possible therapeutic targeting.

Allergy-Related Diseases and Risk of Breast Cancer: The Role of Skewed Immune System on This Association

Background

The role of allergy in breast cancer (BC) development remains inconclusive. A comprehensive review article is required to present and discuss all findings on this topic and to clarify the association between allergic disorders and the risk of BC.

Objective

We aimed to explain the association between atopy, different types of allergic disorders, and the risk of BC. Moreover, we explored the immunological mechanism behind this association.

Methods

We electronically reviewed publications in PubMed from 1979 to 2018 relating to atopy, allergy, asthma, atopic dermatitis, allergic rhinitis, food allergy, drug allergy, immunoglobulin E (IgE) or prick test, and BC.

Results

Most of the identified studies demonstrated nonsignificant results. However, the pattern of the results indicated an increased risk of BC in individuals with a history of allergies. The majority of studies reported higher prevalence of atopic dermatitis and allergic rhinitis among individuals with BC compared to the control groups. Similarity, most of the studies revealed an increased risk of BC among people with a positive history of atopic using IgE specific or prick test. However, a null association was reported in most of the asthmatic studies, and controversial results were detected in the individuals with history of food and drug allergies.

Conclusion

The majority of findings were not statistically significant. Moreover, bias and other methodological problems are the major issues, which make it challenging to compare the findings of different studies and reach a strong conclusive result. However, the pattern of the results from most studies indicated that allergic diseases might be associated with an increased risk of BC. Skewed immune system toward T-helper 2 might have an important role in this association.

The role of the immune system in brain metastasis

Metastatic brain tumors are the most common brain tumors in adults. With numerous successful advancements in systemic treatment of most common cancer types, brain metastasis is becoming increasingly important in the overall prognosis of cancer patients. Brain metastasis of peripheral tumor is the result of complex interplay of primary tumor, immune system and central nervous system microenvironment. Once formed, brain metastases hide behind the blood brain barrier and become inaccessible to chemotherapies that are otherwise successful in targeting systemic cancer. The approval of immune checkpoint inhibitors for several common cancers such as advanced melanoma and lung cancers brings with it the opportunity and obligation to further understand the mechanisms of immunosuppression by tumors that spread to the brain as well as the interaction between the brain environment and tumor microenvironment. In this review paper we define the central role of the immune system in the development of brain metastases. We performed a comprehensive review of the literature to outline the molecular mechanisms of immunosuppression used by tumors and how the immune system interacts with the central nervous system to facilitate brain metastasis. In particular we discuss the tumor-type-specific mechanisms of metastasis of cancers that preferentially metastasize to the brain as well as the therapies that effectively modulate the immune response, such as immune checkpoint inhibitors and vaccines.

Overexpression of thymic stromal lymphopoietin is correlated with poor prognosis in epithelial ovarian carcinoma

Thymic stromal lymphopoietin (TSLP) is an IL-7-like cytokine that has been reported to be associated with several malignant tumors. The present study aimed to evaluate its role in epithelial ovarian carcinoma (EOC). The mRNA levels of TSLP in human EOC samples and EOC cell lines were determined. Then, the expression of TSLP was examined in 144 clinical tissue microarray samples and correlated with clinicopathological factors. Finally, the correlation between TSLP overexpression and prognosis of EOC patients was analyzed. Our data show that mRNA levels of TSLP were significantly higher in EOC tissues and cell lines. Chi-square tests revealed that TSLP overexpression in EOC was significantly associated with age, histological type, Federation of Gynecology and Obstetrics (FIGO) stage, histological differentiation, pelvic involvement, and lymphatic metastasis. Kaplan–Meier survival analysis revealed that poor prognosis was significantly correlated with older age, advanced FIGO stage, poor histological differentiation, pelvic involvement, lymphatic involvement, or TSLP overexpression (P<0.05). Additionally, multivariate Cox regression analysis confirmed pelvic involvement and TSLP overexpression as independent prognostic factors for both overall and disease-free survival. Taken altogether, TSLP overexpression reflects a more malignant phenotype and TSLP may be a novel biomarker for EOC.

Thymic stromal lymphopoietin in human pancreatic ductal adenocarcinoma: expression and prognostic significance

Thymic stromal lymphopoietin (TSLP) has emerged as an important, but contradictory, player conditioning tumor growth. In certain contexts, by driving T helper (h) 2 responses via tumor-associated OX40 Ligand (OX40L)⁺ dendritic cells (DCs), TSLP may play a pro-tumorigenic role. The study elucidates the importance of TSPL in pancreatic ductal adenocarcinoma (PDAC), by analyzing: i) TSLP levels in PDAC cell-line supernatants and plasma from patients with locally-advanced/metastatic PDAC, pre- and post-treatment with different chemotherapeutic protocols, in comparison with healthy donors; ii) TSLP and OX40L expression in PDAC and normal pancreatic tissues, by immunohistochemistry; iii) OX40L expression on ex vivo-generated normal DCs in the presence of tumor-derived TSLP, by flow cytometry; iv) clinical relevance in terms of diagnostic and prognostic value and influence on treatment modality and response.

Some PDAC cell lines, such as BxPC-3, expressed both TSLP mRNA and protein. Normal DCs, generated ex vivo in the presence of TSLP-rich-cell supernatants, displayed increased expression of OX40L, reduced by the addition of a neutralizing anti-TSLP polyclonal antibody. OX40L⁺ cells were detected in pancreatic tumor inflammatory infiltrates. Abnormally elevated TSLP levels were detected in situ in tumor cells and, systemically, in locally-advanced/metastatic PDAC patients. Of the chemotherapeutic protocols applied, gemcitabine plus oxaliplatin (GEMOX) significantly increased circulating TSLP levels. Elevated plasma TSLP concentration was associated with shorter overall survival and increased risk of poor outcome. Plasma TSLP measurement successfully discriminated PDAC patients from healthy controls.

These data show that TSLP secreted by pancreatic cancer cells may directly impact PDAC biology and patient outcome.

Tumor-derived high-mobility group box 1 and thymic stromal lymphopoietin are involved in modulating dendritic cells to activate T regulatory cells in a mouse model

High-mobility group box 1 (HMGB1) is involved in the tumor-associated activation of regulatory T cells (Treg), but the mechanisms remain unknown. In a mouse tumor model, silencing HMGB1 in tumor cells or inhibiting tumor-derived HMGB1 not only dampened the capacity of tumor cells to produce thymic stromal lymphopoietin (TSLP), but also aborted the tumor-associated modulation of Treg-activating DC. Tumor-derived HMGB1 triggered the production of TSLP by tumor cells. Importantly, both tumor-derived HMGB1 and TSLP were necessary for modulating DC to activate Treg in a TSLP receptor (TSLPR)-dependent manner. In the therapeutic model, intratumorally inhibiting tumor-derived HMGB1 (causing downstream loss of TSLP production) attenuated Treg activation, unleashed tumor-specific CD8 T cell responses, and elicited CD8α+/CD103+DC- and T cell-dependent antitumor activity. These results suggest a new pathway for the activation of Treg involving in tumor-derived HMGB1 and TSLP, and have important implications for incorporating HMGB1 inhibitors into cancer immunotherapy.

Thymic Stromal Lymphopoietin: To Cut a Long Story Short

Thymic stromal lymphopoietin (TSLP) was identified more than 20 years ago as a secreted factor of a mouse thymic stromal cell line; later, a human orthologue was also identified. The signaling pathway triggered by TSLP has been extensively studied, and upregulation of the cytokine itself is linked to the pathogenesis of numerous Th2-related diseases, including atopic dermatitis, asthma, allergic responses, as well as certain types of cancers. On the other hand, TSLP mediates several immune homeostatic functions in both the gut and the thymus. Thus, a paradox occurs; why is TSLP homeostatic in certain tissues and a hallmark of exacerbated Th2 responses in the aforementioned pathologies? We and others have recently shown that in humans a novel isoform exists; this is a shorter isoform of TSLP whose expression is constitutive and controlled by a separate promoter. Short TSLP isoform mediates the homeostatic functions, whereas the long isoform is expressed at low/undetectable level at steady state and upregulated during inflammation in several tissues. Here we review the most recent data concerning the differential expression of the 2 isoforms and provide a potential explanation to the paradox. TSLP is regarded as a promising target for treatment of relevant pathologies, with a number of clinical trials already underway. It is important to design new strategies aimed at leaving intact the homeostatic effects of the short isoform while targeting the inflammatory effects of the long isoform.

A Multifaceted Role for Myd88-Dependent Signaling in Progression of Murine Mammary Carcinoma

Previous data obtained in our laboratory suggested that there may be constitutive signaling through the myeloid differentiation primary response gene 88 (Myd88)-dependent signaling cascade in murine mammary carcinoma. Here, we extended these findings by showing that, in the absence of an added Toll-like receptor (TLR) agonist, the myddosome complex was preformed in 4T1 tumor cells, and that Myd88 influenced cytoplasmic extracellular signal–regulated kinase (Erk)1/Erk2 levels, nuclear levels of nuclear factor-kappaB (NFκB) and signal transducer and activator of transcription 5 (STAT5), tumor-derived chemokine (C–C motif) ligand 2 (CCL2) expression, and in vitro and in vivo tumor growth. In addition, RNA-sequencing revealed that Myd88-dependent signaling enhanced the expression of genes that could contribute to breast cancer progression and genes previously associated with poor outcome for patients with breast cancer, in addition to suppressing the expression of genes capable of inhibiting breast cancer progression. Yet, Myd88-dependent signaling in tumor cells also suppressed expression of genes that could contribute to tumor progression. Collectively, these data revealed a multifaceted role for Myd88-dependent signaling in murine mammary carcinoma.

Thymic Stromal Chemokine TSLP Acts through Th2 Cytokine Production to Induce Cutaneous T-cell Lymphoma

Thymic stromal lymphopoietin (TSLP) activates dendritic cells to induce Th2-mediated inflammation. Periostin, an extracellular matrix protein produced by fibroblasts, induces chronic inflammation by stimulating TSLP production. Recently, a reinforcing cycle linking Th2-type immune responses with periostin-induced keratinocyte activation has been proposed in atopic dermatitis pathogenesis. In this study, we investigated the role of TSLP and periostin in the development of cutaneous T-cell lymphoma (CTCL), where Th2 cytokines and chemokines are also dominant. TSLP and periostin mRNA expression levels were elevated in CTCL lesional skin, both of which correlated with IL4 expression levels. In vitro and ex vivo, IL4 or IL13 stimulated periostin expression by dermal fibroblasts, and fibroblasts from CTCL lesional skin expressed higher levels of periostin than those from control skin. Serum periostin levels of CTCL patients were also significantly higher than those of healthy individuals. Hut78 and MJ, CTCL cell lines, and peripheral blood mononuclear cells from leukemic CTCL patients expressed the TSLP receptor. TSLP induced production of IL4 and IL13 by Hut78 and MJ cells through the activation of STAT5. Moreover, TSLP induced proliferation of CTCL cells both in vitro and in vivo These data suggest that periostin-mediated TSLP production by keratinocytes directly stimulates CTCL tumor cell growth in addition to inducing a Th2-dominant tumor environment in CTCL. Cancer Res; 76(21); 6241-52. ©2016 AACR.

Generation of Organ-conditioned Media and Applications for Studying Organ-specific Influences on Breast Cancer Metastatic Behavior

Breast cancer preferentially metastasizes to the lymph node, bone, lung, brain and liver in breast cancer patients. Previous research efforts have focused on identifying factors inherent to breast cancer cells that are responsible for this observed metastatic pattern (termed organ tropism), however much less is known about factors present within specific organs that contribute to this process. This is in part because of a lack of in vitro model systems that accurately recapitulate the organ microenvironment. To address this, an ex vivo model system has been established that allows for the study of soluble factors present within different organ microenvironments. This model consists of generating conditioned media from organs (lymph node, bone, lung, and brain) isolated from normal athymic nude mice. The model system has been validated by demonstrating that different breast cancer cell lines display cell-line specific and organ-specific malignant behavior in response to organ-conditioned media that corresponds to their in vivo metastatic potential. This model system can be used to identify and evaluate specific organ-derived soluble factors that may play a role in the metastatic behavior of breast and other types of cancer cells, including influences on growth, migration, stem-like behavior, and gene expression, as well as the identification of potential new therapeutic targets for cancer. This is the first ex vivo model system that can be used to study organ-specific metastatic behavior in detail and evaluate the role of specific organ-derived soluble factors in driving the process of cancer metastasis.

TSLP Expression and High Serum TSLP Level Indicate a Poor Prognosis in Gastric Cancer Patients

BACKGROUND

Thymic stromal lymphopoietin (TSLP) plays an important role in promoting tumor survival, by manipulating the immune response and angiogenesis. However, the clinical significance of TSLP in gastric cancer is unclear.

METHODS

Immunohistochemistry was used to investigate TSLP expression in non-cancerous gastric mucosa and gastric cancer tissue from patients with gastric cancer. Serum TSLP levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Tumors with TSLP expression were significantly larger than those without TSLP expression. TSLP expression was observed more frequently in advanced (T2/T3/T4) than in early (T1) gastric cancer and in stage 3/4 than in stage 1/2. Lymph node metastasis, liver metastasis, positive peritoneal lavage cytology, lymphatic invasion, and vascular invasion occurred significantly more often in TSLP-expressing than in non-expressing tumors. The prognosis of patients with TSLP-positive tumors was significantly worse than that of patients with TSLP-negative tumors. Patients with high serum TSLP concentrations also had a significantly worse prognosis than those with low concentrations. Multivariate analysis identified serum TSLP level as an independent prognostic indicator.

CONCLUSION

TSLP is closely related to the progression of gastric cancer and may predict survival in these patients.

Thymic stromal lymphopoietin and cancer

Originally shown to promote the growth and activation of B cells, thymic stromal lymphopoietin (TSLP) is now known to have wide-ranging effects on both hematopoietic and nonhematopoietic cell lineages. These include dendritic cells, basophils, mast cells, B cells, epithelial cells, and CD4(+), CD8(+), and NK T cells. Although TSLP's role in the promotion of Th2 responses has been studied extensively in the context of lung- and skin-specific allergic disorders, it is becoming increasingly clear that TSLP may impact multiple disease states within multiple organ systems. This review highlights recent advances in the understanding of the surprising role of TSLP in the control of a variety of cancers, both solid tumors and leukemia, in which the TSLP/TSLP receptor axis was shown to be an important regulator.

TSLP induced by estrogen stimulates secretion of MCP-1 and IL-8 and growth of human endometrial stromal cells through JNK and NF-κB signal pathways

It has reported that human endometrial stromal cells (ESCs) express thymic stromal lymphopoietin (TSLP), and TSLP concentrations in the serum and peritoneal fluid were higher in women with endometriosis. Endometriosis is an estrogen-dependent disease. The present study aimed to elucidate whether and how estrogen regulates the growth of ESCs through TSLP. The ESCs behaviors in vitro were verified by SRB assay and Ki67 level detection, respectively. In addition, the effects of estrogen on TSLP and TSLP on the correspondent functional molecules were investigated by ELISA and flow cytometry. Here we found that estrogen stimulated the secretion of TSLP in a dosage-dependent manner. Recombinant human TSLP stimulates the secretion of MCP-1 and IL-8, and markedly promotes the viability and proliferation relative gene Ki-67 expression of ESCs. These effects could be abolished by the inhibitor for JNK or NF-κB signal, respectively. Moreover, not only anti-TSLP neutralizing antibody, but also blocking JNK or NF-κB signal by inhibitor abrogated the stimulatory role in the production of MCP-1 and IL-8, and the growth of ESCs induced by estrogen. Our current study has demonstrated that TSLP is involved in the regulation of estrogen on the secretion of MCP-1 and IL-8, and the growth of ESCs through JNK and NF-κB signal pathways, which suggests that the abnormal high expression of TSLP induced by estrogen may play an important role in ESCs growth and finally contribute to the origin and development of endometriosis.