Batf-Dependent Th17 cells act through IL23R pathway to promote prostate adenocarcinoma initiation and progression.

BACKGROUND: The role of Th17 cells in prostate cancer (PCa) is not fully understood. The transcription factor BATF controls the differentiation of Th17 cells. Mice deficient in Batf do not produce Th17 cells. METHODS: In this study, we aimed to characterize the role of Batf-dependent Th17 cells in PCa by crossbreeding Batf knockout (Batf-/-) mice with mice conditionally mutant for Pten. We found that Batf-/- mice had changes in the morphology of prostate epithelial cells compared to normal mice, and Batf-/- mice deficient in Pten (named Batf-) had smaller prostate size and developed fewer invasive prostate adenocarcinomas than Pten-deficient mice with Batf expression (named Batf+). The prostate tumors in Batf- mice showed reduced proliferation, increased apoptosis, decreased angiogenesis and inflammatory cell infiltration, and activation of NF-κB signaling. Moreover, Batf- mice showed significantly reduced IL-23/IL-23R signaling. In the prostate stroma of Batf- mice, IL-23R-positive cells were decreased considerably compared to Batf+ mice. Splenocytes and prostate tissues from Batf- mice cultured under Th17 differentiation conditions expressed reduced IL-23/IL-23R than cultured cells from Batf+ mice. Anti-IL23p19 antibody treatment of Pten-deficient mice reduced prostate tumors and angiogenesis compared to control IgG-treated mice. In human prostate tumors, BATF mRNA level was positively correlated with IL23A and IL-23R but not RORC. CONCLUSION: Our novel findings underscore the crucial role of IL-23/IL23R signaling in mediating the function of Batf-dependent Th17 cells, thereby promoting PCa initiation and progression. This highlights the Batf-IL-23R axis as a promising target for the development of innovative strategies for PCa prevention and treatment.

Adipose Tissue in Breast Cancer Microphysiological Models to Capture Human Diversity in Preclinical Models.

Female breast cancer accounts for 15.2% of all new cancer cases in the United States, with a continuing increase in incidence despite efforts to discover new targeted therapies. With an approximate failure rate of 85% for therapies in the early phases of clinical trials, there is a need for more translatable, new preclinical in vitro models that include cellular heterogeneity, extracellular matrix, and human-derived biomaterials. Specifically, adipose tissue and its resident cell populations have been identified as necessary attributes for current preclinical models. Adipose-derived stromal/stem cells (ASCs) and mature adipocytes are a normal part of the breast tissue composition and not only contribute to normal breast physiology but also play a significant role in breast cancer pathophysiology. Given the recognized pro-tumorigenic role of adipocytes in tumor progression, there remains a need to enhance the complexity of current models and account for the contribution of the components that exist within the adipose stromal environment to breast tumorigenesis. This review article captures the current landscape of preclinical breast cancer models with a focus on breast cancer microphysiological system (MPS) models and their counterpart patient-derived xenograft (PDX) models to capture patient diversity as they relate to adipose tissue.

The Use of Urinary Bladder Matrix for Reconstructing Avulsed Traumatic Soft Tissue Injuries to the Maxillofacial Region.

INTRODUCTION: The purpose of the study was to provide an overview of our initial experience utilizing urinary bladder matrix (UBM) for reconstructing avulsed injuries resulting from trauma. MATERIALS AND METHODS: This retrospective case series evaluated patients presented with avulsed soft tissue injuries to the head and neck who underwent reconstruction with UBM. Patients were treated by Oral and Maxillofacial Surgery Service in Louisiana State University Health Sciences Center (Baton Rouge, LA). Descriptive variables were collected. Descriptive statistics were calculated. RESULTS: Eight patients (mean age 55.8 y) met our inclusion criteria. Wounds were located in the scalp (n=2, 25%), mandible (n=2, 25%), upper eyelid (n=1, 12.5%), cheek (n=1, 12.5%), nose (n=1, 12.5%), or neck (n=1, 12.5%). The depth of the wound extended from the skin to the subcutaneous tissue (n=1, 12.5%), muscle (n=2, 25%), bone (n=3, 37.5%), and/or cartilage (n=1, 12.5%). The mean wound diameter was 47.9 cm 2 (range 17-85 cm 2 ). Wounds were classified as acute (n=6, 75%) or chronic wounds (n=2, 25%). At 6 months, all patients had achieved complete healing with no need for additional surgical procedures (n=8, 100%) with a mean healing time of 36.5 days (range 14-90 d). CONCLUSION: Urinary bladder matrix minimize donor-side morbidity, eliminates contraction, and offers a wide range of product sizes to cover a wide range of maxillofacial soft tissue defects in a single-stage manner.

A Novel Controlled PTEN-Knockout Mouse Model for Prostate Cancer Study.

Prostate cancer (PCa) is associated with advanced age, but how age contributes to prostate carcinogenesis remains unknown. The prostate-specific Pten conditional knockout mouse model closely imitates human PCa initiation and progression. To better understand how age impacts PCa in an experimental model, we have generated a spatially and temporally controlled Pten-null PCa murine model at different ages (aged vs. non-aged) of adult mice. Here, we present a protocol to inject the Cre-expressing adenovirus with luciferin tag, intraductally, into the prostate anterior lobes of Pten-floxed mice; Pten-loss will be triggered post-Cre expression at different ages. In vivo imaging of luciferin signal following viral infection confirmed successful delivery of the virus and Cre activity. Immunohistochemical staining confirmed prostate epithelial-specific expression of Cre recombinase and the loss of Pten and activation of P-Akt, P-S6, and P-4E-BP1. The Cre-expression, Pten ablation, and activated PI3K/AKT/mTOR pathways were limited to the prostate epithelium. All mice developed prostatic epithelial hyperplasia within 4 weeks after Pten ablation and prostatic intraepithelial neoplasia (PIN) within 8 weeks post-Pten ablation. Some PINs had progressed to invasive adenocarcinoma at 8-16 weeks post-Pten ablation. Aged mice exhibited significantly accelerated PI3K/AKT/mTOR signaling and increased PCa onset and progression compared to young mice. The viral infection success rate is ∼80%. This model will be beneficial for investigations of cancer-related to aging.

Dual inhibition of MEK1/2 and MEK5 suppresses the EMT/migration axis in triple-negative breast cancer through FRA-1 regulation.

Triple-negative breast cancer (TNBC) presents a clinical challenge due to the aggressive nature of the disease and a lack of targeted therapies. Constitutive activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway has been linked to chemoresistance and metastatic progression through distinct mechanisms, including activation of epithelial-to-mesenchymal transition (EMT) when cells adopt a motile and invasive phenotype through loss of epithelial markers (CDH1), and acquisition of mesenchymal markers (VIM, CDH2). Although MAPK/ERK1/2 kinase inhibitors (MEKi) are useful antitumor agents in a clinical setting, including the Food and Drug Administration (FDA)-approved MEK1,2 dual inhibitors cobimetinib and trametinib, there are limitations to their clinical utility, primarily adaptation of the BRAF pathway and ocular toxicities. The MEK5 (HGNC: MAP2K5) pathway has important roles in metastatic progression of various cancer types, including those of the prostate, colon, bone and breast, and elevated levels of ERK5 expression in breast carcinomas are linked to a worse prognoses in TNBC patients. The purpose of this study is to explore MEK5 regulation of the EMT axis and to evaluate a novel pan-MEK inhibitor on clinically aggressive TNBC cells. Our results show a distinction between the MEK1/2 and MEK5 cascades in maintenance of the mesenchymal phenotype, suggesting that the MEK5 pathway may be necessary and sufficient in EMT regulation while MEK1/2 signaling further sustains the mesenchymal state of TNBC cells. Furthermore, additive effects on MET induction are evident through the inhibition of both MEK1/2 and MEK5. Taken together, these data demonstrate the need for a better understanding of the individual roles of MEK1/2 and MEK5 signaling in breast cancer and provide a rationale for the combined targeting of these pathways to circumvent compensatory signaling and subsequent therapeutic resistance.

Breast Cancer Reconstruction: Design Criteria for a Humanized Microphysiological System.

International regulatory agencies such as the Food and Drug Administration have mandated that the scientific community develop humanized microphysiological systems (MPS) as an in vitro alternative to animal models in the near future. While the breast cancer research community has long appreciated the importance of three-dimensional growth dynamics in their experimental models, there are remaining obstacles preventing a full conversion to humanized MPS for drug discovery and pathophysiological studies. This perspective evaluates the current status of human tissue-derived cells and scaffolds as building blocks for an "idealized" breast cancer MPS based on bioengineering design principles. It considers the utility of adipose tissue as a potential source of endothelial, lymphohematopoietic, and stromal cells for the support of breast cancer epithelial cells. The relative merits of potential MPS scaffolds derived from adipose tissue, blood components, and synthetic biomaterials is evaluated relative to the current "gold standard" material, Matrigel, a murine chondrosarcoma-derived basement membrane-enriched hydrogel. The advantages and limitations of a humanized breast cancer MPS are discussed in the context of in-process and destructive read-out assays. Impact statement Regulatory authorities have highlighted microphysiological systems as an emerging tool in breast cancer research. This has been led by calls for more predictive human models and reduced animal experimentation. This perspective describes how human-derived cells, extracellular matrices, and hydrogels will provide the building blocks to create breast cancer models that accurately reflect diversity at multiple levels, that is, patient ethnicity, pathophysiology, and metabolic status.

Novel bone-targeted parathyroid hormone-related peptide antagonists inhibit breast cancer bone metastases.

Patients with advanced breast cancer often develop bone metastases. Treatment is limited to palliative care. Parathyroid hormone (PTH)/parathyroid hormone-related peptide (PTHrP) antagonists for bone metastases failed clinically due to short half-life and inadequate concentration in bone. We synthesized two novel PTHrP antagonists fused to an inert bacterial collagen binding domain (CBD) that directs drugs to bone. PTH(7-33)-CBD is an N-terminal truncated PTHrP antagonist. [W2]PTH(1-33)-CBD is an PTHrP inverse-agonist. The aim of this study was to assess PTH(7-33)-CBD to reduce breast cancer bone metastases and prevent osteolytic destruction in mice and to assess both drugs for apoptosis of breast cancer cells in vitro and inhibition of PTH receptor (PTHR1). PTH(7-33)-CBD (1000 µg/kg, subcutaneous) or vehicle was administered 24 h prior to MDA-MB-231 breast cancer cell inoculation into the tibia marrow. Weekly tumor burden and bone density were measured. Pharmacokinetic analysis of PTH(7-33)-CBD in rat serum was evaluated. Drug effect on cAMP accumulation in SaOS-2 osteosarcoma cells and apoptosis of MDA-MB-231 cells was assessed. PTH(7-33)-CBD reduced MDA-MB-231 tumor burden and osteolytic destruction in mice 4-5 weeks post-treatment. PTH(7-33)-CBD (1000 µg/kg i.v. and subcutaneous) in rats was rapidly absorbed with peak concentration 5-min and terminal half-life 3-h. Bioavailability by the subcutaneous route was 43% relative to the i.v. route. PTH(7-33)-CBD was detected only on rat periosteal bone surfaces that stained positive for collagen-1. PTH(7-33)-CBD and [W2]PTH(1-33)-CBD (10-8M) blocked basal and PTH agonist-induced cAMP accumulation in SaOS-2 osteosarcoma cells. Both drugs induced PTHR1-dependent apoptosis of MDA-MB-231 cells in vitro. Novel bone-targeted PTHrP antagonists represent a new paradigm for treatment of breast cancer bone metastases.

ERK5 Is Required for Tumor Growth and Maintenance Through Regulation of the Extracellular Matrix in Triple Negative Breast Cancer.

Conventional mitogen-activated protein kinase (MAPK) family members regulate diverse cellular processes involved in tumor initiation and progression, yet the role of ERK5 in cancer biology is not fully understood. Triple-negative breast cancer (TNBC) presents a clinical challenge due to the aggressive nature of the disease and a lack of targeted therapies. ERK5 signaling contributes to drug resistance and metastatic progression through distinct mechanisms, including activation of epithelial-to-mesenchymal transition (EMT). More recently a role for ERK5 in regulation of the extracellular matrix (ECM) has been proposed, and here we investigated the necessity of ERK5 in TNBC tumor formation. Depletion of ERK5 expression using the CRISPR/Cas9 system in MDA-MB-231 and Hs-578T cells resulted in loss of mesenchymal features, as observed through gene expression profile and cell morphology, and suppressed TNBC cell migration. In vivo xenograft experiments revealed ERK5 knockout disrupted tumor growth kinetics, which was restored using high concentration Matrigel™ and ERK5-ko reduced expression of the angiogenesis marker CD31. These findings implicated a role for ERK5 in the extracellular matrix (ECM) and matrix integrity. RNA-sequencing analyses demonstrated downregulation of matrix-associated genes, integrins, and pro-angiogenic factors in ERK5-ko cells. Tissue decellularization combined with cryo-SEM and interrogation of biomechanical properties revealed that ERK5-ko resulted in loss of key ECM fiber alignment and mechanosensing capabilities in breast cancer xenografts compared to parental wild-type cells. In this study, we identified a novel role for ERK5 in tumor growth kinetics through modulation of the ECM and angiogenesis axis in breast cancer.

Hypochlorous Acid: A Review.

The surgeon needs to have an inexpensive, available, nontoxic, and practical disinfectant that is effective in sanitizing against the COVID-19 (Coronavirus Disease 2019) virus. The purpose of this article was to review the evidence for using hypochlorous acid in the office setting on a daily basis. The method used to assemble recommendations was a review of the literature including evidence for this solution when used in different locations and industries other than the oral-maxillofacial clinic facility. The results indicate that this material can be used with a high predictability for disinfecting against the COVID-19 (Coronavirus Disease 2019) virus.

CD4+ T helper 17 cell response of aged mice promotes prostate cancer cell migration and invasion.

BACKGROUND: Aging is the most important risk factor for prostate cancer (PCa), but how age contributes to PCa is poorly understood. Aging is characterized by low-grade systemic inflammation (i.e., inflammaging) that is often attributed to the progressive activation of immune cells over time, which may play an important role in prostate carcinogenesis. Th17 response is elevated in aging humans and mice, but it remains unknown whether it is increased in prostate tissue or contributes to prostate carcinogenesis during aging. In this study, we aimed to determine the role of age-related Th17 response in PCa cell growth, migration, and invasion. METHODS: C57BL/6J (B6) mouse was used as an aging animal model and the prostate histopathology during aging was analyzed. Splenic CD4+ T cells were isolated from young (16-20 weeks old) and aged (96-104 weeks old) mice, and cultured in the presence of plate-bound anti-CD3/anti-CD28, with or without Th17 differentiation conditions. The cells were collected and used for subsequent flow cytometry or quantitative reverse transcription polymerase chain reaction. The supernatant was collected and used to treat PCa cell lines. The treated PCa cells were analyzed for cell viability, migration, invasion, and nuclear factor kappa B (NF-κB) signaling. RESULTS: Aged mice had enlarged prostate glands and increased morphological alterations, with not only increased inflammatory cell infiltration but also increased Th17 cytokines in prostate tissue, compared to young mice. Naïve CD4+ T cells from aged mice differentiated increased interleukin (IL)-17-expressing cells. CD4+ T cells from aged mice spleen had increased Th17 cells, Th17 cytokines and Th17/Treg ratio compared to young mice. Factors secreted from aged CD4+ T cells, especially from ex vivo differentiated Th17 cells, not only promoted PCa cell viability, migration, and invasion but also activated the NF-κB signaling in PCa cells compared to young mice. CONCLUSIONS: These results indicate that age-related CD4+ T cells, especially Th17 cells-secreted factors have the potential to contribute to prostate carcinogenesis. Our work could prompt further research using autochthonous PCa mouse models at different ages to elucidate the functional role of Th17 response in prostate carcinogenesis during aging.

Drug resistance profiling of a new triple negative breast cancer patient-derived xenograft model.

BACKGROUND: Triple-negative breast cancer (TNBC) represents an aggressive subtype with limited therapeutic options. Experimental preclinical models that recapitulate their tumors of origin can accelerate target identification, thereby potentially improving therapeutic efficacy. Patient-derived xenografts (PDXs), due to their genomic and transcriptomic fidelity to the tumors from which they are derived, are poised to improve the preclinical testing of drug-target combinations in translational models. Despite the previous development of breast and TNBC PDX models, those derived from patients with demonstrated health-disparities are lacking. METHODS: We use an aggressive TNBC PDX model propagated in SCID/Beige mice that was established from an African-American woman, TU-BcX-2 K1, and assess its metastatic potential and drug sensitivities under distinct in vitro conditions. Cellular derivatives of the primary tumor or the PDX were grown in 2D culture conditions or grown in mammospheres 3D culture. Flow cytometry and fluorescence staining was used to quantify cancer stem cell-like populations. qRT-PCR was used to describe the mesenchymal gene signature of the tumor. The sensitivity of TU-BcX-2 K1-derived cells to anti-neoplastic oncology drugs was compared in adherent cells and mammospheres. Drug response was evaluated using a live/dead staining kit and crystal violet staining. RESULTS: TU-BcX-2 K1 has a low propensity for metastasis, reflects a mesenchymal state, and contains a large burden of cancer stem cells. We show that TU-BcX-2 K1 cells have differential responses to cytotoxic and targeted therapies in 2D compared to 3D culture conditions insofar as several drug classes conferred sensitivity in 2D but not in 3D culture, or cells grown as mammospheres. CONCLUSIONS: Here we introduce a new TNBC PDX model and demonstrate the differences in evaluating drug sensitivity in adherent cells compared to mammosphere, or suspension, culture.

Dual Src Kinase/Pretubulin Inhibitor KX-01, Sensitizes ERα-negative Breast Cancers to Tamoxifen through ERα Reexpression.

Unlike breast cancer that is positive for estrogen receptor-α (ERα), there are no targeted therapies for triple-negative breast cancer (TNBC). ERα is silenced in TNBC through epigenetic changes including DNA methylation and histone acetylation. Restoring ERα expression in TNBC may sensitize patients to endocrine therapy. Expression of c-Src and ERα are inversely correlated in breast cancer suggesting that c-Src inhibition may lead to reexpression of ERα in TNBC. KX-01 is a peptide substrate-targeted Src/pretubulin inhibitor in clinical trials for solid tumors. KX-01 (1 mg/kg body weight-twice daily) inhibited growth of tamoxifen-resistant MDA-MB-231 and MDA-MB-157 TNBC xenografts in nude mice that was correlated with Src kinase inhibition. KX-01 also increased ERα mRNA and protein, as well as increased the ERα targets progesterone receptor (PR), pS2 (TFF1), cyclin D1 (CCND1), and c-myc (MYC) in MDA-MB-231 and MDA-MB-468, but not MDA-MB-157 xenografts. MDA-MB-231 and MDA-MB-468 tumors exhibited reduction in mesenchymal markers (vimentin, ß-catenin) and increase in epithelial marker (E-cadherin) suggesting mesenchymal-to-epithelial transition (MET). KX-01 sensitized MDA-MB-231 and MDA-MB-468 tumors to tamoxifen growth inhibition and tamoxifen repression of the ERα targets pS2, cyclin D1, and c-myc. Chromatin immunoprecipitation (ChIP) of the ERα promoter in KX-01-treated tumors demonstrated enrichment of active transcription marks (acetyl-H3, acetyl-H3Lys9), dissociation of HDAC1, and recruitment of RNA polymerase II. Methylation-specific PCR and bisulfite sequencing demonstrated no alteration in ERα promoter methylation by KX-01. These data demonstrate that in addition to Src kinase inhibition, peptidomimetic KX-01 restores ERα expression in TNBC through changes in histone acetylation that sensitize tumors to tamoxifen.Implications: Src kinase/pretubulin inhibitor KX-01 restores functional ERα expression in ERα- breast tumors, a novel treatment strategy to treat triple-negative breast cancer. Mol Cancer Res; 15(11); 1491-502. ©2017 AACR.

Hyperinsulinemia enhances interleukin-17-induced inflammation to promote prostate cancer development in obese mice through inhibiting glycogen synthase kinase 3-mediated phosphorylation and degradation of interleukin-17 receptor.

Interleukin-17 (IL-17) plays important roles in inflammation, autoimmune diseases, and some cancers. Obese people are in a chronic inflammatory state with increased serum levels of IL-17, insulin, and insulin-like growth factor 1 (IGF1). How these factors contribute to the chronic inflammatory status that promotes development of aggressive prostate cancer in obese men is largely unknown. We found that, in obese mice, hyperinsulinemia enhanced IL-17-induced expression of downstream proinflammatory genes with increased levels of IL-17 receptor A (IL-17RA), resulting in development of more invasive prostate cancer. Glycogen synthase kinase 3 (GSK3) constitutively bound to and phosphorylated IL-17RA at T780, leading to ubiquitination and proteasome-mediated degradation of IL-17RA, thus inhibiting IL-17-mediated inflammation. IL-17RA phosphorylation was reduced, while the IL-17RA levels were increased in the proliferative human prostate cancer cells compared to the normal cells. Insulin and IGF1 enhanced IL-17-induced inflammatory responses through suppressing GSK3, which was shown in the cultured cell lines in vitro and obese mouse models of prostate cancer in vivo. These findings reveal a mechanism underlying the intensified inflammation in obesity and obesity-associated development of aggressive prostate cancer, suggesting that targeting GSK3 may be a potential therapeutic approach to suppress IL-17-mediated inflammation in the prevention and treatment of prostate cancer, particularly in obese men.

Human Adipose Tissue-Derived Stromal/Stem Cells Promote Migration and Early Metastasis of Head and Neck Cancer Xenografts.

BACKGROUND: Fat grafting has become popular for repair of postsurgical/postradiation defects after head/neck cancers resection. Fat graft supplementation with adipose tissue-derived stromal/stem cells (ASCs) is proposed to improve graft viability/efficacy, although the impact of ASCs on head/neck cancer cells is unknown. OBJECTIVES: To determine whether ASCs affect growth, migration, and metastasis of human head/neck cancer. METHODS: Human Cal-27 and SCC-4 head/neck cancer cells were co-cultured human ASCs, or treated with ASC conditioned medium (CM), and cancer cell growth/migration was assessed by MTT, cell count, and scratch/wound healing assays in vitro. Co-injection of 3 × 10(6) Cal-27/green fluorescent protein (GFP) cells and ASCs into the flank of NUDE mice assessed ASC effect on tumor growth/morphology. Quantitation of human chromosome 17 DNA in mouse organs assessed ASC effects on micrometastasis. Primary tumors were evaluated for markers of epithelial-to-mesenchymal transition, matrix metalloproteinases, and angiogenesis by immunohistochemistry. RESULTS: Co-culture of Cal-27 or SCC-4 cells with ASCs from 2 different donors or ASC CM had no effect on cell growth in vitro. However, ASC CM stimulated Cal-27 and SCC-4 migration. Co-injection of ASCs from 2 different donors with Cal-27 cells did not affect tumor volume at 6 weeks, but increased Cal-27 micrometastasis to the brain. Evaluation of tumors sections from 1 ASC donor co-injection revealed that ASCs were viable and well integrated with Cal-27/GFP cells. These tumors exhibited increased MMP2, MMP9, IL-8, and microvessel density. CONCLUSIONS: Human ASCs did not alter growth of human head/neck cancer cells or tumor xenografts, but stimulated migration and early micrometastasis to mouse brain.

Argonaute 2 Expression Correlates with a Luminal B Breast Cancer Subtype and Induces Estrogen Receptor Alpha Isoform Variation.

Estrogen receptor alpha (ERα) signaling pathways are frequently disrupted in breast cancer and contribute to disease progression. ERα signaling is multifaceted and many ERα regulators have been identified including transcription factors and growth factor pathways. More recently, microRNAs (miRNAs) are shown to deregulate ERα activity in breast carcinomas, with alterations in both ERα and miRNA expression correlating to cancer progression. In this study, we show that a high expression of Argonaute 2 (AGO2), a translation regulatory protein and mediator of miRNA function, correlates with the luminal B breast cancer subtype. We further demonstrate that a high expression of AGO2 in ERα+ tumors correlates with a poor clinical outcome. MCF-7 breast cancer cells overexpressing AGO2 (MCF7-AGO2) altered ERα downstream signaling and selective ERα variant expression. Enhanced ERα-36, a 36 kDa ERα isoform, protein and gene expression was observed in vitro. Through quantitative polymerase chain reaction (qPCR), we demonstrate decreased basal expression of the full-length ERα and progesterone receptor genes, in addition to loss of estrogen stimulated gene expression in vitro. Despite the loss, MCF-7-AGO2 cells demonstrated increased estrogen stimulated tumorigenesis in vivo. Together with our clinical findings on AGO2 expression and the luminal B subtype, we suggest that AGO2 is a regulator of altered ERα signaling in breast tumors.

Estrogen receptor alpha phosphorylation and its functional impact in human breast cancer.

Estrogen receptor α (ERα) is a member of the nuclear receptor superfamily of transcription factors that regulates cell proliferation, differentiation and homeostasis in various tissues. Sustained exposure to estrogen/estradiol (E2) increases the risk of breast, endometrial and ovarian cancers. ERα function is also regulated by phosphorylation through various kinase signaling pathways that will impact various ERα functions including chromatin interaction, coregulator recruitment and gene expression, as well impact breast tumor growth/morphology and breast cancer patient response to endocrine therapy. However, many of the previously characterized ERα phosphorylation sites do not fully explain the impact of receptor phosphorylation on ERα function. This review discusses work from our laboratory toward understanding a role of ERα site-specific phosphorylation in ERα function and breast cancer. The key findings discussed in this review are: (1) the effect of site specific ERα phosphorylation on temporal recruitment of ERα and unique coactivator complexes to specific genes; (2) the impact of stable disruption of ERα S118 and S167 phosphorylation in breast cancer cells on eliciting unique gene expression profiles that culminate in significant effects on breast cancer growth/morphology/migration/invasion; (3) the Src kinase signaling pathway that impacts ERα phosphorylation to alter ERα function; and (4) circadian disruption by light exposure at night leading to elevated ERK1/2 and Src kinase and phosphorylation of ERα, concomitant with tamoxifen resistance in breast tumor models. Results from these studies demonstrate that even changes to single ERα phosphorylation sites can have a profound impact on ERα function in breast cancer. Future work will extend beyond single site phosphorylation analysis toward identification of specific patterns/profiles of ERα phosphorylation under different physiological/pharmacological conditions to understand how common phosphorylation profiles in breast cancer program specific physiological endpoints such as growth, apoptosis, migration/invasion, and endocrine therapy response.

Circadian and melatonin disruption by exposure to light at night drives intrinsic resistance to tamoxifen therapy in breast cancer.

Resistance to endocrine therapy is a major impediment to successful treatment of breast cancer. Preclinical and clinical evidence links resistance to antiestrogen drugs in breast cancer cells with the overexpression and/or activation of various pro-oncogenic tyrosine kinases. Disruption of circadian rhythms by night shift work or disturbed sleep-wake cycles may lead to an increased risk of breast cancer and other diseases. Moreover, light exposure at night (LEN) suppresses the nocturnal production of melatonin that inhibits breast cancer growth. In this study, we used a rat model of estrogen receptor (ERα(+)) MCF-7 tumor xenografts to demonstrate how altering light/dark cycles with dim LEN (dLEN) speed the development of breast tumors, increasing their metabolism and growth and conferring an intrinsic resistance to tamoxifen therapy. These characteristics were not observed in animals in which the circadian melatonin rhythm was not disrupted, or in animals subjected to dLEN if they received nocturnal melatonin replacement. Strikingly, our results also showed that melatonin acted both as a tumor metabolic inhibitor and a circadian-regulated kinase inhibitor to reestablish the sensitivity of breast tumors to tamoxifen and tumor regression. Together, our findings show how dLEN-mediated disturbances in nocturnal melatonin production can render tumors insensitive to tamoxifen.

Adipose stem cell therapy in cancer reconstruction: a critical review.

Found in most mesenchymally derived organs, mesenchymal stem cells are undifferentiated cells capable of developing into many cell types. Adipose stem cells are a type of mesenchymal stem cell easily extracted from lipoaspirate, often readily available, and are conformable to the tissue defect. Their ability for self-renewal, unlimited proliferation and proangiogenic, and immunomodulatory properties have made them attractive adjuncts in plastic surgery. Since the discovery of pluripotent cells in adipose tissue, plastic surgeons have applied the technology toward improving wound healing, soft tissue augmentation, and tissue engineering. More recently, some surgeons have used adipose stem cells in cancer reconstruction. By mixing lipoaspirate with concentrated fractions of adipose stem cells through a technique termed cell-assisted lipotransfer, plastic surgeons have claimed improved aesthetic results. Promising early results have been tempered by in vitro and animal studies demonstrating increased tumor proliferation and metastasis rates with the use of adipose and other mesenchymal stem cells. This review provides a succinct yet comprehensive overview of the current literature evaluating the oncologic risks associated with adipose stem cell use in cancer.

Suppression of triple-negative breast cancer metastasis by pan-DAC inhibitor panobinostat via inhibition of ZEB family of EMT master regulators.

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that lacks effective targeted therapies. The epithelial-to-mesenchymal transition (EMT) is a key contributor in the metastatic process. We previously showed the pan-deacetylase inhibitor LBH589 induces CDH1 expression in TNBC cells, suggesting regulation of EMT. The purpose of this study was to examine the effects of LBH589 on the metastatic qualities of TNBC cells and the role of EMT in this process. A panel of breast cancer cell lines (MCF-7, MDA-MB-231, and BT-549), drugged with LBH589, was examined for changes in cell morphology, migration, and invasion in vitro. The effect on in vivo metastasis was examined using immunofluorescent staining of lung sections. EMT gene expression profiling was used to determine LBH589-induced changes in TNBC cells. ZEB overexpression studies were conducted to validate requirement of ZEB in LBH589-mediated proliferation and tumorigenesis. Our results indicate a reversal of EMT by LBH589 as demonstrated by altered morphology and altered gene expression in TNBC. LBH589 was shown to be a more potent inhibitor of EMT than other HDAC inhibitors, SAHA and TMP269. Additionally, we found that LBH589 inhibits metastasis of MDA-MB-231 cells in vivo. These effects of LBH589 were mediated in part by inhibition of ZEB, as overexpression of ZEB1 or ZEB2 mitigated the effects of LBH589 on MDA-MB-231 EMT-associated gene expression, migration, invasion, CDH1 expression, and tumorigenesis. These data indicate therapeutic potential of LBH589 in targeting EMT and metastasis of TNBC.