Androgen-induced cell migration: role of androgen receptor/filamin A association

Role of actin-binding proteins in prostate cancer

The molecular mechanisms driving the onset and metastasis of prostate cancer remain poorly understood. Actin, under the control of actin-binding proteins (ABPs), plays a crucial role in shaping the cellular cytoskeleton, which in turn supports the morphological alterations in normal cells, as well as the invasive spread of tumor cells. Previous research indicates that ABPs of various types serve distinct functions, and any disruptions in their activities could predispose individuals to prostate cancer. These ABPs are intricately implicated in the initiation and advancement of prostate cancer through a complex array of intracellular processes, such as severing, linking, nucleating, inducing branching, assembling, facilitating actin filament elongation, terminating elongation, and promoting actin molecule aggregation. As such, this review synthesizes existing literature on several ABPs linked to prostate cancer, including cofilin, filamin A, and fascin, with the aim of shedding light on the molecular mechanisms through which ABPs influence prostate cancer development and identifying potential therapeutic targets. Ultimately, this comprehensive examination seeks to contribute to the understanding and management of prostate diseases.

Charting the importance of filamin A posttranslational modifications

Filamin A is an essential protein in the cell cytoskeleton because of its actin binding properties and unique homodimer rod-shaped structure, which organises actin into three-dimensional orthogonal networks imperative to cell motility, spreading and adhesion. Filamin A is subject to extensive posttranslational modification (PTM) which serves to co-ordinate cellular architecture and to modulate its large protein-protein interaction network which is key to the protein's role as a cellular signalling hub. Characterised PTMs include phosphorylation, irreversible cleavage, ubiquitin mediated degradation, hydroxylation and O-GlcNAcylation, with preliminary evidence of tyrosylation, carbonylation and acetylation. Each modification and its relation to filamin A function will be described here. These modifications are often aberrantly applied in a range of diseases including, but not limited to, cancer, cardiovascular disease and neurological disease and we discuss the concept of target specific PTMs with novel therapeutic modalities. In summary, our review represents a topical 'one-stop-shop' that enables understanding of filamin A function in cell homeostasis and provides insight into how a variety of modifications add an extra level of Filamin A control.

Filamin A in triple negative breast cancer

Triple-negative breast cancer is a rare but highly heterogeneous breast cancer subtype with a limited choice of specific treatments. Chemotherapy remains the only efficient treatment, but its side effects and the development of resistance consolidate the urgent need to discover new targets. In TNBC, filamin A expression correlates to grade and TNM stage. Accordingly, this protein could constitute a new target for this BC subtype. Even if most of the data indicates its direct involvement in cancer progression, some contrasting results underline the need to deepen the studies. To elucidate a possible function of this protein as a TNBC marker, we summarized the main characteristic of filamin A and its involvement in physiological and pathological processes such as cancer. Lastly, we scrutinized its actions in triple-negative breast cancer and highlighted the need to increase the number of studies useful to better clarify the role of this versatile protein as a marker and target in TNBC, alone or in "collaboration" with other proteins with a relevant role in this BC subgroup.

Filamin A cooperates with the androgen receptor in preventing skeletal muscle senescence

Aging induces a slow and progressive decrease in muscle mass and function, causing sarcopenia. Androgens control muscle trophism and exert important anabolic functions through the binding to the androgen receptor. Therefore, analysis of the androgen receptor-mediated actions in skeletal muscle might provide new hints for a better understanding of sarcopenia pathogenesis. In this study, we report that expression of the androgen receptor in skeletal muscle biopsies from 20 subjects is higher in young, as compared with old subjects. Co-immunoprecipitation experiments reveal that the androgen receptor is complexed with filamin A mainly in young, that in old subjects. Therefore, we have in depth analyzed the role of such complex using C2C12 myoblasts that express a significant amount of the androgen receptor. In these cells, hormone stimulation rapidly triggers the assembly of the androgen receptor/filamin A complex. Such complex prevents the senescence induced by oxidative stress in C2C12 cells, as disruption of the androgen receptor/filamin A complex by Rh-2025u stapled peptide re-establishes the senescent phenotype in C2C12 cells. Simultaneously, androgen stimulation of C2C12 cells rapidly triggers the activation of various signaling effectors, including Rac1, focal adhesion kinase, and mitogen-activated kinases. Androgen receptor blockade by bicalutamide or perturbation of androgen receptor/filamin A complex by Rh-2025u stapled peptide both reverse the hormone activation of signaling effectors. These findings further reinforce the role of the androgen receptor and its extranuclear partners in the rapid hormone signaling that controls the functions of C2C12 cells. Further investigations are needed to promote clinical interventions that might ameliorate muscle cell function as well the clinical outcome of age-related frailty.

The Impaired Wound Healing Process Is a Major Factor in Remodeling of the Corneal Epithelium in Adult and Adolescent Patients With Keratoconus

Purpose

Keratoconus (KTCN) is the most common corneal ectasia, characterized by pathological cone formation. Here, to provide an insight into the remodeling of the corneal epithelium (CE) during the course of the disease, we evaluated topographic regions of the CE of adult and adolescent patients with KTCN.

Methods

The CE samples from 17 adult and 6 adolescent patients with KTCN, and 5 control CE samples were obtained during the CXL and PRK procedures, respectively. Three topographic regions, central, middle, and peripheral, were separated toward RNA sequencing and MALDI-TOF/TOF Tandem Mass Spectrometry. Data from transcriptomic and proteomic investigations were consolidated with the morphological and clinical findings.

Results

The critical elements of the wound healing process, epithelial-mesenchymal transition, cell-cell communications, and cell-extracellular matrix interactions were altered in the particular corneal topographic regions. Abnormalities in pathways of neutrophils degranulation, extracellular matrix processing, apical junctions, IL, and IFN signaling were revealed to cooperatively disorganize the epithelial healing. Deregulation of the epithelial healing, G2M checkpoints, apoptosis, and DNA repair pathways in the middle CE topographic region in KTCN explains the presence of morphological changes in the corresponding doughnut pattern (a thin cone center surrounded by a thickened annulus). Despite similar morphological characteristics of CE samples in adolescents and adults with KTCN, their transcriptomic features were different. Values of the posterior corneal elevation differentiated adults with KTCN from adolescents with KTCN and correlated with the expression of TCHP, SPATA13, CNOT3, WNK1, TGFB2, and KRT12 genes.

Conclusions

Identified molecular, morphological, and clinical features indicate the effect of impaired wound healing on corneal remodeling in KTCN CE.

Androgens and NGF Mediate the Neurite-Outgrowth through Inactivation of RhoA

Steroid hormones and growth factors control neuritogenesis through their cognate receptors under physiological and pathological conditions. We have already shown that nerve growth factor and androgens induce neurite outgrowth of PC12 cells through a reciprocal crosstalk between the NGF receptor, TrkA and the androgen receptor. Here, we report that androgens or NGF induce neuritogenesis in PC12 cells through inactivation of RhoA. Ectopic expression of the dominant negative RhoA N19 promotes, indeed, the neurite-elongation of unchallenged and androgen- or NGF-challenged PC12 cells and the increase in the expression levels of βIII tubulin, a specific neuronal marker. Pharmacological inhibition of the Ser/Thr kinase ROCK, an RhoA effector, induces neuritogenesis in unchallenged PC12 cells, and potentiates the effect of androgens and NGF, confirming the role of RhoA/ROCK axis in the neuritogenesis induced by androgen and NGF, through the phosphorylation of Akt. These findings suggest that therapies based on new selective androgen receptor modulators and/or RhoA/ROCK inhibitors might exert beneficial effects in the treatment of neuro-disorders, neurological diseases and ageing-related processes.

Nonmalignant AR-positive prostate epithelial cells and cancer cells respond differently to androgen

Prostate cancer research suffers from the lack of suitable models to study the role of normal cells in prostate carcinogenesis. To address this challenge, we developed a cell line model mimicking luminal prostate epithelial cells by modifying the immortalized prostate epithelial cell line RWPE-1 to constitutively express the androgen receptor (AR). RWPE-1-AR cells express known AR target genes, and exhibit coexpression of luminal and basal markers characteristic of transient amplifying cells, and an RNA signature resembling prostate luminal progenitor cells. Under unstimulated conditions, constitutive AR expression does not have a biologically significant effect on the proliferation of RWPE-1 cells, but when stimulated by androgens, growth is retarded. The transcriptional response of RWPE-1-AR cells to androgen stimulation involves suppression of the growth-related KRAS pathway and is thus markedly different from that of the prostate cancer cell line LNCaP and its derivative AR-overexpressing LNCaP-ARhi cells, in which growth- and cancer-related pathways are upregulated. Hence, the nonmalignant AR-positive RWPE-1-AR cell line model could be used to study the transformation of the prostate epithelium.

Metformin counteracts stimulatory effects induced by insulin in primary breast cancer cells

Background

Metabolic disorders are associated with increased incidence, aggressive phenotype and poor outcome of breast cancer (BC) patients. For instance, hyperinsulinemia is an independent risk factor for BC and the insulin/insulin receptor (IR) axis is involved in BC growth and metastasis. Of note, the anti-diabetic metformin may be considered in comprehensive therapeutic approaches in BC on the basis of its antiproliferative effects obtained in diverse pre-clinical and clinical studies.

Methods

Bioinformatics analysis were performed using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project. The naturally immortalized BC cell line, named BCAHC-1, as well as cancer-associated fibroblasts (CAFs) derived from BC patients were used as model systems. In order to identify further mechanisms that characterize the anticancer action of metformin in BC, we performed gene expression and promoter studies as well as western blotting experiments. Moreover, cell cycle analysis, colony and spheroid formation, actin cytoskeleton reorganization, cell migration and matrigel drops evasion assays were carried out to provide novel insights on the anticancer properties of metformin.

Results

We first assessed that elevated expression and activation of IR correlate with a worse prognostic outcome in estrogen receptor (ER)-positive BC. Thereafter, we established that metformin inhibits the insulin/IR-mediated activation of transduction pathways, gene changes and proliferative responses in BCAHC-1 cells. Then, we found that metformin interferes with the insulin-induced expression of the metastatic gene CXC chemokine receptor 4 (CXCR4), which we found to be associated with poor disease-free survival in BC patients exhibiting high levels of IR. Next, we ascertained that metformin prevents a motile phenotype of BCAHC-1 cells triggered by the paracrine liaison between tumor cells and CAFs upon insulin activated CXCL12/CXCR4 axis.

Conclusions

Our findings provide novel mechanistic insights regarding the anti-proliferative and anti-migratory effects of metformin in both BC cells and important components of the tumor microenvironment like CAFs. Further investigations are warranted to corroborate the anticancer action of metformin on the tumor mass toward the assessment of more comprehensive strategies halting BC progression, in particular in patients exhibiting metabolic disorders and altered insulin/IR functions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03463-y.

Androgen/Wnt/β-catenin signal axis augments cell proliferation of the mouse erectile tissue, corpus cavernosum

The murine penile erectile tissues including corpus cavernosum (CC) are composed of blood vessels, smooth muscle, and connective tissue, showing marked sexual differences. It has been known that the androgens are required for sexually dimorphic organogenesis. It is however unknown about the features of androgen signaling during mouse CC development. It is also unclear how androgen-driven downstream factors are involved such processes. In the current study, we analyzed the onset of sexually dimorphic CC formation based on histological analyses, the dynamics of androgen receptor (AR) expression, and regulation of cell proliferation. Of note, we identified Dickkopf-related protein 2 (Dkk2), an inhibitor of β-catenin signaling, was predominantly expressed in female CC compared with male. Furthermore, administration of androgens resulted in activation of β-catenin signaling. We have found the Sox9 gene, one of the essential markers for chondrocyte, was specifically expressed in the developing CC. Hence, we utilized CC-specific, Sox9 ^CreERT2 , β-catenin conditional mutant mice. Such mutant mice showed defective cell proliferation. Furthermore, introduction of activated form of β-catenin mutation (gain of function mutation for Wnt/β-catenin signaling) in CC induced augmented cell proliferation. Altogether, we revealed androgen-Wnt/β-catenin signal dependent cell proliferation was essential for sexually dimorphic CC formation. These findings open new avenues for understanding developmental mechanisms of androgen-dependent cell proliferation during sexual differentiation.

Patient-specific Boolean models of signalling networks guide personalised treatments

Prostate cancer is the second most occurring cancer in men worldwide. To better understand the mechanisms of tumorigenesis and possible treatment responses, we developed a mathematical model of prostate cancer which considers the major signalling pathways known to be deregulated. We personalised this Boolean model to molecular data to reflect the heterogeneity and specific response to perturbations of cancer patients. A total of 488 prostate samples were used to build patient-specific models and compared to available clinical data. Additionally, eight prostate cell line-specific models were built to validate our approach with dose-response data of several drugs. The effects of single and combined drugs were tested in these models under different growth conditions. We identified 15 actionable points of interventions in one cell line-specific model whose inactivation hinders tumorigenesis. To validate these results, we tested nine small molecule inhibitors of five of those putative targets and found a dose-dependent effect on four of them, notably those targeting HSP90 and PI3K. These results highlight the predictive power of our personalised Boolean models and illustrate how they can be used for precision oncology.

Targeted activation of androgen receptor signaling in the periosteum improves bone fracture repair

Low testosterone level is an independent predictor of osteoporotic fracture in elderly men as well as increased fracture risk in men undergoing androgen deprivation. Androgens and androgen receptor (AR) actions are essential for bone development and homeostasis but their linkage to fracture repair remains unclear. Here we found that AR is highly expressed in the periosteum cells and is co-localized with a mesenchymal progenitor cell marker, paired-related homeobox protein 1 (Prrx1), during bone fracture repair. Mice lacking the AR gene in the periosteum expressing Prrx1-cre (AR^-/Y;Prrx1::Cre) but not in the chondrocytes (AR^-/Y;Col-2::Cre) exhibits reduced callus size and new bone volume. Gene expression data analysis revealed that the expression of several collagens, integrins and cell adhesion molecules were downregulated in periosteum-derived progenitor cells (PDCs) from AR^-/Y;Prrx1::Cre mice. Mechanistically, androgens-AR signaling activates the AR/ARA55/FAK complex and induces the collagen-integrin α2β1 gene expression that is required for promoting the AR-mediated PDCs migration. Using mouse cortical-defect and femoral graft transplantation models, we proved that elimination of AR in periosteum of host mice impairs fracture healing, regardless of AR existence of transplanted donor graft. While testosterone implanted scaffolds failed to complete callus bridging across the fracture gap in AR^-/Y;Prrx1::Cre mice, cell-based transplantation using DPCs re-expressing AR could lead to rescue bone repair. In conclusion, targeting androgen/AR axis in the periosteum may provide a novel therapy approach to improve fracture healing.

A Small Peptide Targeting the Ligand-Induced Androgen Receptor/Filamin a Interaction Inhibits the Invasive Phenotype of Prostate Cancer Cells

Prostate cancer (PC) is one of the most widespread malignancies among males worldwide. The androgen receptor (AR) plays a major role in prostate cancer development and progression and is the main target of PC therapy. Nonetheless, its action is not yet fully elucidated. We report here that the AR associates with Filamin A (FlnA) promoting migration and invasiveness of various PC-derived cells after androgen challenging. Inhibition of the AR/FlnA complex assembly by a very low concentration of Rh-2025u, an AR-derived peptide specifically interfering with this association, impairs such phenotype in monolayer cells and in 3D models. This study, together with our recent data in cancer-associated fibroblasts (CAFs), indicates that targeting the AR/FlnA complex could improve the clinical management of invasive PC, as the limited number of new drugs reaching the market suggests that we must re-examine the way invasive PC is currently treated. In this context, the synthesis of new biologically active molecules, such as the Rh-2025u peptide, which has been shown to efficiently interfere in the complex assembly in CAFs and PC cells, should overcome the limits of current available therapies, mostly based on hormone antagonists.

Therapeutic potential of TRPM8 antagonists in prostate cancer

Transient receptor potential melastatin-8 (TRPM8) represents an emerging target in prostate cancer, although its mechanism of action remains unclear. Here, we have characterized and investigated the effects of TRPM8 modulators in prostate cancer aggressiveness disclosing the molecular mechanism underlying their biological activity. Patch-clamp and calcium fluorometric assays were used to characterize the synthesized compounds. Androgen-stimulated prostate cancer-derived cells were challenged with the compounds and the DNA synthesis was investigated in a preliminary screening. The most effective compounds were then employed to inhibit the pro-metastatic behavior of in various PC-derived cells, at different degree of malignancy. The effect of the compounds was then assayed in prostate cancer cell-derived 3D model and the molecular targets of selected compounds were lastly identified using transcriptional and non-transcriptional reporter assays. TRPM8 antagonists inhibit the androgen-dependent prostate cancer cell proliferation, migration and invasiveness. They are highly effective in reverting the androgen-induced increase in prostate cancer cell spheroid size. The compounds also revert the proliferation of castrate-resistant prostate cancer cells, provided they express the androgen receptor. In contrast, no effects were recorded in prostate cancer cells devoid of the receptor. Selected antagonists interfere in non-genomic androgen action and abolish the androgen-induced androgen receptor/TRPM8 complex assembly as well as the increase in intracellular calcium levels in prostate cancer cells. Our results shed light in the processes controlling prostate cancer progression and make the transient receptor potential melastatin-8 as a ‘druggable’ target in the androgen receptor-expressing prostate cancers.

Communication between cells: exosomes as a delivery system in prostate cancer

Despite the considerable efforts in screening and diagnostic protocols, prostate cancer still represents the second leading cause of cancer-related death in men. Many patients with localized disease and low risk of recurrence have a favourable outcome. In a substantial proportion of patients, however, the disease progresses and becomes aggressive. The mechanisms that promote prostate cancer progression remain still debated. Many findings point to the role of cross-communication between prostate tumor cells and their surrounding microenvironment during the disease progression. Such a connection fosters survival, proliferation, angiogenesis, metastatic spreading and drug-resistance of prostate cancer. Recent years have seen a profound interest in understanding the way by which prostate cancer cells communicate with the surrounding cells in the microenvironment. In this regard, direct cell-to-cell contacts and soluble factors have been identified. Increasing evidence indicates that PC cells communicate with the surrounding cells through the release of extracellular vesicles, mainly the exosomes. By directly acting in stromal or prostate cancer epithelial cells, exosomes represent a critical intercellular communication system. By querying the public database ( https://pubmed.ncbi.nlm.nih.gov ) for the past 10 years, we have found more than four hundred papers. Among them, we have extrapolated the most relevant about the role of exosomes in prostate cancer malignancy and progression. Emerging data concerning the use of these vesicles in diagnostic management and therapeutic guidance of PC patients are also presented. Video Abstract.

The Role of Androgen Receptor in Cross Talk Between Stromal Cells and Prostate Cancer Epithelial Cells

Prostate cancer (PCa) lists as the second most lethal cancer for men in western countries, and androgen receptor (AR) plays a central role in its initiation and progression, which prompts the development of androgen deprivation therapy (ADT) as the standard treatment. Prostate tumor microenvironment, consisting of stromal cells and extracellular matrix (ECM), has dynamic interactions with PCa epithelial cells and affects their growth and invasiveness. Studies have shown that both genomic and non-genomic AR signaling pathways are involved in the biological regulation of PCa epithelial cells. In addition, AR signaling in prostate stroma is also involved in PCa carcinogenesis and progression. Loss of AR in PCa stroma is clinically observed as PCa progresses to advanced stage. Especially, downregulation of AR in stromal fibroblasts dysregulates the expression levels of ECM proteins, thus creating a suitable environment for PCa cells to metastasize. Importantly, ADT treatment enhances this reciprocal interaction and predisposes stromal cells to promote cell invasion of PCa cells. During this process, AR in PCa epithelium actively responds to various stimuli derived from the surrounding stromal cells and undergoes enhanced degradation while elevating the expression of certain genes such as MMP9 responsible for cell invasion. AR reduction in epithelial cells also accelerates these cells to differentiate into cancer stem-like cells and neuroendocrine cells, which are AR-negative PCa cells and inherently resistant to ADT treatments. Overall, understanding of the cross talk between tumor microenvironment and PCa at the molecular level may assist the development of novel therapeutic strategies against this disease. This review will provide a snapshot of AR's action when the interaction of stromal cells and PCa cells occurs.

RhoGTPase Signalling in Cancer Progression and Dissemination

Rho GTPases are a family of small G proteins that regulate a wide array of cellular processes related to their key roles controlling the cytoskeleton. On the other hand, cancer is a multi-step disease caused by the accumulation of genetic mutations and epigenetic alterations, from the initial stages of cancer development when cells in normal tissues undergo transformation, to the acquisition of invasive and metastatic traits, responsible for a large number of cancer related deaths. In this review, we discuss the role of Rho GTPase signalling in cancer in every step of disease progression. Rho GTPases contribute to tumour initiation and progression, by regulating proliferation and apoptosis, but also metabolism, senescence and cell stemness. Rho GTPases play a major role in cell migration, and in the metastatic process. They are also involved in interactions with the tumour microenvironment and regulate inflammation, contributing to cancer progression. After years of intensive research, we highlight the importance of relevant models in the Rho GTPase field, and we reflect on the therapeutic opportunities arising for cancer patients.

Probing mechanobiological role of filamin A in migration and invasion of human U87 glioblastoma cells using submicron soft pillars

Filamin A (FLNa) belongs to an actin-binding protein family in binding and cross-linking actin filaments into a three-dimensional structure. However, little attention has been given to its mechanobiological role in cancer cells. Here, we quantitatively investigated the role of FLNa by analyzing the following parameters in negative control (NC) and FLNa-knockdown (KD) U87 glioma cells using submicron pillars (900 nm diameter and 2 μm height): traction force (TF), rigidity sensing ability, cell aspect ratio, migration speed, and invasiveness. During the initial phase of cell adhesion (< 1 h), FLNa-KD cells polarized more slowly than did NC cells, which can be explained by the loss of rigidity sensing in FLNa-KD cells. The higher motility of FLNa-KD cells relative to NC cells can be explained by the high TF exerted by FLNa-KD cells when compared to NC cells, while the higher invasiveness of FLNa-KD cells relative to NC cells can be explained by a greater number of filopodia in FLNa-KD cells than in NC cells. Our results suggest that FLNa plays important roles in suppressing motility and invasiveness of U87 cells.

Targeting androgen receptor signaling with MicroRNAs and Curcumin: a promising therapeutic approach for Prostate Cancer Prevention and intervention

Prostate cancer (PC) is a multifactorial disease characterized by the abrogation of androgen receptor signaling. Advancement in microbiology techniques has highlighted the significant role of microRNAs (miRNAs) in the progression of PC cells from an androgen-dependent to an androgen-independent state. At that stage, prostate tumors also fail to respond to currently practiced hormone therapies. So, studies in recent decades are focused on investigating the anti-tumor effects of natural compounds in PC. Curcumin is widely recognized and now of huge prestige for its anti-proliferative abilities in different types of cancer. However, its limited solubility, compatibility, and instability in the aqueous phase are major hurdles when administering. Nanoformulations have proven to be an excellent drug delivery system for various drugs and can be used as potential delivery platforms for curcumin in PC. In this review, a shed light is given on the miRNAs-mediated regulation of androgen receptor (AR) signaling and miRNA-curcumin interplay in PC, as well as on curcumin-based nanoformulations that can be used as possible therapeutic solutions for PC.

The androgen receptor/filamin A complex as a target in prostate cancer microenvironment

Prostate cancer represents the major cause of cancer-related death in men and patients frequently develop drug-resistance and metastatic disease. Most studies focus on hormone-resistance mechanisms related to androgen receptor mutations or to the acquired property of prostate cancer cells to over-activate signaling pathways. Tumor microenvironment plays a critical role in prostate cancer progression. However, the mechanism involving androgen/androgen receptor signaling in cancer associated fibroblasts and consequences for prostate cancer progression still remains elusive. We now report that prostate cancer associated fibroblasts express a transcriptional-incompetent androgen receptor. Upon androgen challenging, the receptor co-localizes with the scaffold protein filamin A in the extra-nuclear compartment of fibroblasts, thus mediating their migration and invasiveness. Cancer-associated fibroblasts move towards epithelial prostate cancer cells in 2D and 3D cultures, thereby inducing an increase of the prostate cancer organoid size. Androgen enhances both these effects through androgen receptor/filamin A complex assembly in cancer-associated fibroblasts. An androgen receptor-derived stapled peptide, which disrupts the androgen receptor/filamin A complex assembly, abolishes the androgen-dependent migration and invasiveness of cancer associated fibroblasts. Notably, the peptide impairs the androgen-induced invasiveness of CAFs in 2D models and reduces the overall tumor area in androgen-treated 3D co-culture. The androgen receptor in association with β1 integrin and membrane type-matrix metalloproteinase 1 activates a protease cascade triggering extracellular matrix remodeling. The peptide also impairs the androgen activation of this cascade. This study offers a potential new marker, the androgen receptor/filamin A complex, and a new therapeutic approach targeting intracellular pathways activated by the androgen/androgen receptor axis in prostate cancer-associated fibroblasts. Such a strategy, alone or in combination with conventional therapies, may allow a more efficient treatment of prostate cancer.

Targeting the cytoskeleton against metastatic dissemination

Cancer is a pathology characterized by a loss or a perturbation of a number of typical features of normal cell behaviour. Indeed, the acquisition of an inappropriate migratory and invasive phenotype has been reported to be one of the hallmarks of cancer. The cytoskeleton is a complex dynamic network of highly ordered interlinking filaments playing a key role in the control of fundamental cellular processes, like cell shape maintenance, motility, division and intracellular transport. Moreover, deregulation of this complex machinery contributes to cancer progression and malignancy, enabling cells to acquire an invasive and metastatic phenotype. Metastasis accounts for 90% of death from patients affected by solid tumours, while an efficient prevention and suppression of metastatic disease still remains elusive. This results in the lack of effective therapeutic options currently available for patients with advanced disease. In this context, the cytoskeleton with its regulatory and structural proteins emerges as a novel and highly effective target to be exploited for a substantial therapeutic effort toward the development of specific anti-metastatic drugs. Here we provide an overview of the role of cytoskeleton components and interacting proteins in cancer metastasis with a special focus on small molecule compounds interfering with the actin cytoskeleton organization and function. The emerging involvement of microtubules and intermediate filaments in cancer metastasis is also reviewed.

Androgen Signaling in the Tumor Microenvironment

The key function of mesenchymal/stromal androgen receptor (AR) signaling for prostate development has been well documented by tissue recombination experiments. Some studies have addressed the expression and function of AR in stromal cells in prostate cancer, yet our understanding of the role of stromal AR in other tissues beyond prostate is still insufficient.Genomic analysis has revealed that cellular responses to androgens differ between epithelial and stromal cells. AR in stromal cells seems not to act via classical AR transcription factors such as FOXA1 but rather depends on the JUN/AP1 complex. Stromal AR appears to have tumor-promoting and tumor-protective functions depending on tumor stage. Loss of AR signaling in fibroblasts has been detected already in premalignant lesions in the skin and prostate and has been associated with tumor induction in xenografts of skin cancer and aggressive disease features and poor patient prognosis in prostate cancer. Moreover, AR expression is found on virtually all tissue-infiltrating immune cells and plays critical roles in immune cell function. These findings suggest a potential deleterious impact of current androgen deprivation therapies which inhibit both epithelial and stromal AR, highlighting the need to develop tissue-specific AR inhibitors.

FLN-1/filamin is required to anchor the actomyosin cytoskeleton and for global organization of sub-cellular organelles in a contractile tissue

Actomyosin networks are organized in space, direction, size, and connectivity to produce coordinated contractions across cells. We use the C. elegans spermatheca, a tube composed of contractile myoepithelial cells, to study how actomyosin structures are organized. FLN-1/filamin is required for the formation and stabilization of a regular array of parallel, contractile, actomyosin fibers in this tissue. Loss of fln-1 results in the detachment of actin fibers from the basal surface, which then accumulate along the cell junctions and are stabilized by spectrin. In addition, actin and myosin are captured at the nucleus by the linker of nucleoskeleton and cytoskeleton complex (LINC) complex, where they form large foci. Nuclear positioning and morphology, distribution of the endoplasmic reticulum and the mitochondrial network are also disrupted. These results demonstrate that filamin is required to prevent large actin bundle formation and detachment, to prevent excess nuclear localization of actin and myosin, and to ensure correct positioning of organelles.

Role of androgen and microRNA in triple-negative breast cancer

Breast cancer (BC) is the most frequent type of malignancy affecting females worldwide. Molecular-based studies resulted in an identification of at least four subtypes of breast carcinoma, including luminal A and luminal B, Human growth factor receptor (HER-2)-enriched and triple-negative tumors (basal-like and normal breast-like). A proportion of BC cases are of the triple-negative breast cancer (TNBC) type. TNBC lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and HER-2, and is known to express androgen receptor (AR) at considerable levels. AR has been shown to promote the progression of TNBC. However, the exact mechanisms have yet to be unraveled. One of these mechanisms could be through regulating the expression of microRNA (miRNA) molecules, which play an important regulatory role in BC through post-transcriptional gene silencing. Activation of AR controls the expression of miRNA molecules, which target selective mRNAs, consequently, affecting protein expression. In this review we attempt to elucidate the relations between AR and miRNA in TNBC.

Role of αVβ3 in Prostate Cancer: Metastasis Initiator and Important Therapeutic Target

In prostate cancer, distant organ metastasis is the leading cause of patient death. Although the mechanism of malignant tumor metastasis is unclear, studies have confirmed that integrin αVβ3 plays an important role in this process. In prostate cancer, αVβ3 mediates adhesion, invasion, immune escape and neovascularization through interactions with different ligands. Among these ligands and in addition to proteins that are directly related to tumor invasion, other proteins that contain the RGD structure could also bind to αVβ3 and cause a number of biological effects. In this article, we summarized the ligand and downstream proteins related to αVβ3-mediated prostate cancer metastasis as well as some diagnostic and therapeutic measures targeting αVβ3.

High fat diet causes distinct aberrations in the testicular proteome

Diet has important effects on normal physiology and the potential deleterious effects of high fat diets and obesity on male reproductive health are being increasingly described. We conducted a histological review of the effects of chronic high fat (HF) diet (using a mouse model fed a 45% fat diet for 21 weeks) with a discovery proteomic study to assess for changes in the abundance of proteins in the testis. Mice on a HF diet became obese and developed glucose intolerance. Using mass spectrometry, we identify 102 proteins affected in the testis of obese mice. These included structural proteins important for the blood testis barrier (filamin A, FLNA), proteins involved in oxidative stress responses (spermatogenesis associated 20, SPATA-20) and lipid homoeostasis (sterol regulatory element-binding protein 2, SREBP2 and apolipoprotein A1, APOA1). In addition, an important regulator protein paraspeckle component 1, PSPC-1, which interacts with the androgen receptor was significantly downregulated. Proteomic data was validated using both Western blotting and immunostaining which confirmed and localised protein expression in both mouse and human testis using biopsy specimens. This study focused mainly on the abnormalities that occurred at the protein level and as a result, we have identified several candidate proteins and conducted pathway analysis around the effects of HF diet on the testis providing novel insights not previously described. Some of the identified targets could be targeted therapeutically and future work is directed in this area.

Small Ones to Fight a Big Problem-Intervention of Cancer Metastasis by Small Molecules

Metastasis represents the most lethal attribute of cancer and critically limits successful therapies in many tumor entities. The clinical need is defined by the fact that all cancer patients, who have or who will develop distant metastasis, will experience shorter survival. Thus, the ultimate goal in cancer therapy is the restriction of solid cancer metastasis by novel molecularly targeted small molecule based therapies. Biomarkers identifying cancer patients at high risk for metastasis and simultaneously acting as key drivers for metastasis are extremely desired. Clinical interventions targeting these key molecules will result in high efficiency in metastasis intervention. In result of this, personalized tailored interventions for restriction and prevention of cancer progression and metastasis will improve patient survival. This review defines crucial biological steps of the metastatic cascade, such as cell dissemination, migration and invasion as well as the action of metastasis suppressors. Targeting these biological steps with tailored therapeutic strategies of intervention or even prevention of metastasis using a wide range of small molecules will be discussed.

Development of Prostate Cancer Organoid Culture Models in Basic Medicine and Translational Research

Prostate cancer (PC) is the most prevalent cancer in men and the second main cause of cancer-related death in Western society. The lack of proper PC models that recapitulate the molecular and genomic landscape of clinical disease has hampered progress toward translational research to understand the disease initiation, progression, and therapeutic responses in each patient. Although several models have been developed, they hardly emulated the complicated PC microenvironment. Precision medicine is an emerging approach predicting appropriate therapies for individual cancer patients by means of various analyses of individual genomic profiling and targeting specific cancer pathways. In PC, precision medicine also has the potential to impose changes in clinical practices. Here, we describe the various PC models with special focus on PC organoids and their values in basic medicine, personalized therapy, and translational researches in vitro and in vivo, which could help to achieve the full transformative power of cancer precision medicine.

Sin1 promotes proliferation and invasion of prostate cancer cells by modulating mTORC2-AKT and AR signaling cascades

AIMS

Prostate cancer (PCa) is the most common type of cancer and a major cause of death in men worldwide. Aberrant Androgen receptor (AR) and PI3K-AKT signaling are very frequent in PCa patients and, therefore, considered as therapeutic targets in the clinic. Sin1 is an essential component of mTORC2 complex, which determines full AKT activation and PCa development in PTEN^-/- mice. Here we examined the role of Sin1 in human PCa cell lines and respective tumor samples.

MAIN METHODS

Western blotting and immunohistochemistry (IHC) were performed to analyze the expression of Sin1-mTORC2-AKT related proteins in human PCa cells, as well as prostate tumors and normal tissue counterparts. Cell viability and invasion assays were also pursued in the presence or not of Sin1 in PCa cells. Immunoprecipitation assays were additionally carried out to examine the interaction of Sin1 with AR.

KEY FINDINGS

We have presently demonstrated that high levels of Sin1 expression in human PCa tissues correlate with cancer progression. Sin1-mediated cell proliferation and invasion of PCa cells occurs by regulating mTORC2-AKT signaling, epithelial-mesenchymal transition and matrix metalloproteinases. Moreover, androgens are able to induce Sin1 expression, which is further translocated to the nucleus of PCa cells. Finally, Sin1 interacts with AR to suppress its transcriptional activity.

SIGNIFICANCE

Taken together, these data indicate that both Sin1-mediated mTORC2-AKT signaling and Sin1-AR interaction regulate PCa development. Hence, Sin1 may be considered a novel biomarker of PCa progression.

Non-nuclear AR Signaling in Prostate Cancer

Despite the key role played by androgen receptor (AR) in tumor cell aggressiveness and prostate cancer (PCa) progression, its function in the tumor microenvironment (TME) is still controversial. Increasing studies highlight the crucial role played by TME modulation in treatment outcome and tumor cell spreading. In this context, targeting specific constituents of the TME could be considered an alternative approach to classic treatments directed against cancer cells. Currently, androgen deprivation therapy (ADT) is a routinely adopted strategy in the management of PCa, with initial success, and consecutive fail. A possible justification to this is the fact that ADT aims to target all the transcription/translation-related activities of AR, which are typical of tumor epithelial cells. Less is still known about side effects of ADT on TME. Cancer Associated Fibroblasts (CAFs), for example, express a classic AR, mostly confined in the extra-nuclear portion of the cell. In CAFs ADT exerts a plethora of non-transcriptional effects, depending by the protein partner linked to AR, leading to cell migration, proliferation, and differentiation. In recent years, substantial progress in the structure-function relationships of AR, identification of its binding partners and function of protein complexes including AR have improved our knowledge of its signaling axis. Important AR non-genomic effects and lots of its cytoplasmatic binding partners have been described, pointing out a fine control of AR non-genomic pathways. Accordingly, new AR inhibitors have been designed and are currently under investigation. Prompt development of new approaches to target AR or block recruitment of its signaling effectors, or co-activators, is urgently needed. The present review takes an in-depth look at current literature, furnishing an exhaustive state-of-the-art overview of the non-genomic role of AR in PCa, with particular emphasis on its involvement in TME biology.

ZBTB46, SPDEF, and ETV6: Novel Potential Biomarkers and Therapeutic Targets in Castration-Resistant Prostate Cancer

Prostate cancer (PCa) is the second most common killer among men in Western countries. Targeting androgen receptor (AR) signaling by androgen deprivation therapy (ADT) is the current therapeutic regime for patients newly diagnosed with metastatic PCa. However, most patients relapse and become resistant to ADT, leading to metastatic castration-resistant PCa (CRPC) and eventually death. Several proposed mechanisms have been proposed for CRPC; however, the exact mechanism through which CRPC develops is still unclear. One possible pathway is that the AR remains active in CRPC cases. Therefore, understanding AR signaling networks as primary PCa changes into metastatic CRPC is key to developing future biomarkers and therapeutic strategies for PCa and CRPC. In the current review, we focused on three novel biomarkers (ZBTB46, SPDEF, and ETV6) that were demonstrated to play critical roles in CRPC progression, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) drug resistance, and the epithelial-to-mesenchymal transition (EMT) for patients treated with ADT or AR inhibition. In addition, we summarize how these potential biomarkers can be used in the clinic for diagnosis and as therapeutic targets of PCa.

Nerve Growth Factor Induces Proliferation and Aggressiveness In Prostate Cancer Cells

Resistance to hormone therapy and disease progression is the major challenge in clinical management of prostate cancer (PC). Drugs currently used in PC therapy initially show a potent antitumor effects, but PC gradually develops resistance, relapses and spreads. Most patients who fail primary therapy and have recurrences eventually develop castration-resistant prostate cancer (CRPC), which is almost incurable. The nerve growth factor (NGF) acts on a variety of non-neuronal cells by activating the NGF tyrosine-kinase receptor, tropomyosin receptor kinase A (TrkA). NGF signaling is deregulated in PC. In androgen-dependent PC cells, TrkA mediates the proliferative action of NGF through its crosstalk with the androgen receptor (AR). Epithelial PC cells, however, acquire the ability to express NGF and TrkA, as the disease progresses, indicating a role for NGF/TrkA axis in PC progression and androgen-resistance. We here report that once activated by NGF, TrkA mediates proliferation, invasiveness and epithelial-mesenchymal transition (EMT) in various CRPC cells. NGF promotes organoid growth in 3D models of CRPC cells, and specific inhibition of TrkA impairs all these responses. Thus TrkA represents a new biomarker to target in CRPC.

Androgens Induce Invasiveness of Triple Negative Breast Cancer Cells Through AR/Src/PI3-K Complex Assembly

Breast cancer (BC) is still characterized by high morbidity and mortality. A specific BC subtype named triple negative BC (TNBC) lacks estrogen and progesterone receptors (ER and PR, respectively) and is characterized by the absence of overexpression/amplification of human epidermal growth factor receptor 2 (HER2). The androgen receptor (AR) is expressed in TNBC, although its function in these cancers is still debated. Moreover, few therapeutic options are currently available for the treatment of TNBC. In this study, we have used TNBC-derived MDA-MB231 and MDA-MB453 cells that, albeit at different extent, both express AR. Androgen challenging induces migration and invasiveness of these cells. Use of the anti-androgen bicalutamide or AR knockdown experiments show that these effects depend on AR. Furthermore, the small peptide, S1, which mimics the AR proline-rich motif responsible for the interaction of AR with SH3-Src, reverses the effects in both cell lines, suggesting that the assembly of a complex made up of AR and Src drives the androgen-induced motility and invasiveness. Co-immunoprecipitation experiments in androgen-treated MDA-MB231 and MDA-MB453 cells show that the AR/Src complex recruits p85α, the regulatory subunit of PI3-K. In such a way, the basic machinery leading to migration and invasiveness is turned-on. The S1 peptide inhibits motility and invasiveness of TNBC cells and disrupts the AR/Src/p85α complex assembly in MDA-MB231 cells. This study shows that the rapid androgen activation of Src/PI3-K signaling drives migration and invasiveness of TNBC cells and suggests that the S1 peptide is a promising therapeutic option for these cancers.

Estrogens Modulate Somatostatin Receptors Expression and Synergize With the Somatostatin Analog Pasireotide in Prostate Cells

Prostate cancer (PC) is one of the most frequently diagnosed cancers and a leading cause of cancer-related deaths in Western society. Current PC therapies prevalently target the functions of androgen receptor (AR) and may only be effective within short time periods, beyond which the majority of PC patients progress to castration-resistant PC (CRPC) and metastatic disease. The role of estradiol/estradiol receptor (ER) axis in prostate transformation and PC progression is well established. Further, considerable efforts have been made to investigate the mechanism by which somatostatin (SST) and somatostatin receptors (SSTRs) influence PC growth and progression. A number of therapeutic strategies, such as the combination of SST analogs with other drugs, show, indeed, strong promise. However, the effect of the combined treatment of SST analogs and estradiol on proliferation, epithelial mesenchyme transition (EMT) and migration of normal- and cancer-derived prostate cells has not been investigated so far. We now report that estradiol plays anti-proliferative and pro-apoptotic effect in non-transformed EPN prostate cells, which express both ERα and ERβ. A weak apoptotic effect is observed in transformed CPEC cells that only express low levels of ERβ. Estradiol increases, mainly through ERα activation, the expression of SSTRs in EPN, but not CPEC cells. As such, the hormone enhances the anti-proliferative effect of the SST analog, pasireotide in EPN, but not CPEC cells. Estradiol does not induce EMT and the motility of EPN cells, while it promotes EMT and migration of CPEC cells. Addition of pasireotide does not significantly modify these responses. Altogether, our results suggest that pasireotide may be used, alone or in combination with other drugs, to limit the growth of prostate proliferative diseases, provided that both ER isoforms (α and β) are present. Further investigations are needed to better define the cross talk between estrogens and SSTRs as well as its role in PC.

The Divergent Function of Androgen Receptor in Breast Cancer; Analysis of Steroid Mediators and Tumor Intracrinology

Androgen receptor (AR) is the most widely expressed steroid receptor protein in normal breast tissue and is detectable in approximately 90% of primary breast cancers and 75% of metastatic lesions. However, the role of AR in breast cancer development and progression is mired in controversy with evidence suggesting it can either inhibit or promote breast tumorigenesis. Studies have shown it to antagonize estrogen receptor alpha (ERα) DNA binding, thereby preventing pro-proliferative gene transcription; whilst others have demonstrated AR to take on the mantle of a pseudo ERα particularly in the setting of triple negative breast cancer. Evidence for a potentiating role of AR in the development of endocrine resistant breast cancer has also been mounting with reports associating high AR expression with poor response to endocrine treatment. The resurgence of interest into the function of AR in breast cancer has resulted in various emergent clinical trials evaluating anti-AR therapy and selective androgen receptor modulators in the treatment of advanced breast cancer. Trials have reported varied response rates dependent upon subtype with overall clinical benefit rates of ~19-29% for anti-androgen monotherapy, suggesting that with enhanced patient stratification AR could prove efficacious as a breast cancer therapy. Androgens and AR have been reported to facilitate tumor stemness in some cancers; a process which may be mediated through genomic or non-genomic actions of the AR, with the latter mechanism being relatively unexplored in breast cancer. Steroidogenic ligands of the AR are produced in females by the gonads and as sex-steroid precursors secreted from the adrenal glands. These androgens provide an abundant reservoir from which all estrogens are subsequently synthesized and their levels are undiminished in the event of standard hormonal therapeutic intervention in breast cancer. Steroid levels are known to be altered by lifestyle factors such as diet and exercise; understanding their potential role in dictating the function of AR in breast cancer development could therefore have wide-ranging effects in prevention and treatment of this disease. This review will outline the endogenous biochemical drivers of both genomic and non-genomic AR activation and how these may be modulated by current hormonal therapies.

ZIP9 but not the androgen receptor mediates testosterone-induced migratory activity of metastatic prostate cancer cells

LNCaP cells are derived from a metastatic lesion of human prostate adenocarcinoma. They express the classical androgen receptor (AR) and ZIP9, a Zn²⁺ transporter that also binds testosterone and mediates signaling by interacting with G-proteins. Our results show that LNCaP cells respond to testosterone by mobilizing their migratory machinery. Their exposure to testosterone triggers the formation of lamellipodia, reorganization of the actin cytoskeleton, phosphorylation of focal adhesion kinase (FAK) at Tyr925 and of paxillin at Tyr118, expression of matrix metalloproteinase 2 (MMP-2), and cell migration. Silencing ZIP9 expression by means of siRNA does not affect the responsiveness of the classical AR to testosterone; however, it prevents all of the testosterone effects described above: formation of lamellipodia cannot be induced, stimulation of FAK or paxillin phosphorylation or MMP-2 expression is prevented, and cell migration does not take place in the absence of ZIP9. The data presented show that testosterone/ZIP9 interactions might have not only physiological but also pathophysiological relevance. The fact that the migratory machinery of a metastatic prostate cancer cell line is activated exclusively through testosterone/ZIP9 and not through testosterone/AR interactions suggests that targeting specific inhibition of testosterone/ZIP9-mediated events might help in developing new therapeutic strategies against androgen-induced progression of prostate cancer.

Extracellular Vesicles in the Adaptive Process of Prostate Cancer during Inhibition of Androgen Receptor Signaling by Enzalutamide

Current treatments for advanced prostate cancer focus on inhibition of the androgen receptor (AR) by androgen deprivation therapy (ADT). However, complex interactions mediated by tumor suppressors, oncogenes, aberrations of AR expression, or de novo androgen production have been shown to induce the adaptive response of prostate cancer, leading to the development of castration resistant prostate cancer. In this study, we report the effects of AR antagonist, enzalutamide on the protein contents of extracellular vesicles (EVs). EVs mediate cell-to-cell communication and increasing evidence shows the role of EVs in promoting cancer survival and metastasis. We found that treatment with enzalutamide alters the secretion of EVs, one of which is a plasma membrane calcium pump, ATP2B1/PMCA ATPase, as an AR-regulated EV protein. We highlight the networks of interactions between AR, Ca²⁺ , and ATP2B1, where the extracellular proteins thrombospondin-1, gelsolin, and integrinß1 were previously reported as regulators for cancer progression and metastasis, indicating the potential role of EV-derived proteins in mediating calcium homoeostasis under AR inhibition by enzalutamide. Our data further highlight the cross-talk between AR signaling and EV pathways in mediating resistance toward ADT.

Targeting Rac and Cdc42 GTPases in Cancer

Rac and Cdc42 are small GTPases that have been linked to multiple human cancers and are implicated in epithelial to mesenchymal transition, cell-cycle progression, migration/invasion, tumor growth, angiogenesis, and oncogenic transformation. With the exception of the P29S driver mutation in melanoma, Rac and Cdc42 are not generally mutated in cancer, but are overexpressed (gene amplification and mRNA upregulation) or hyperactivated. Rac and Cdc42 are hyperactivated via signaling through oncogenic cell surface receptors, such as growth factor receptors, which converge on the guanine nucleotide exchange factors that regulate their GDP/GTP exchange. Hence, targeting Rac and Cdc42 represents a promising strategy for precise cancer therapy, as well as for inhibition of bypass signaling that promotes resistance to cell surface receptor-targeted therapies. Therefore, an understanding of the regulatory mechanisms of these pivotal signaling intermediates is key for the development of effective inhibitors. In this review, we focus on the role of Rac and Cdc42 in cancer and summarize the regulatory mechanisms, inhibitory efficacy, and the anticancer potential of Rac- and Cdc42-targeting agents. Cancer Res; 78(12); 3101-11. ©2018 AACR.

Signaling regulation and role of filamin A cleavage in Ca2+-stimulated migration of androgen receptor-deficient prostate cancer cells

Ca²⁺, a ubiquitous cellular signal, and filamin A, an actin-binding protein, play an important role in the regulation of cell adhesion, shape and motility. Using transwell filters to analyze cell migration, we found that extracellular Ca²⁺ (Ca_o²⁺) promotes the migration of androgen receptor (AR)-deficient and highly metastatic prostate cancer cell lines (DU145 and PC-3) compared to AR-positive and relatively less metastatic prostate cancer cells (LNCaP). Furthermore, we found that expression of filamin A is up-regulated in DU145 and PC-3 cells, and that Ca_o²⁺ significantly induces the cleavage of filamin A. Silencing expression of Ca²⁺-sensing receptor (CaR) and p115RhoGEF, and treating with leupeptin, a protease inhibitor, and ALLM, a calpain specific inhibitor, we further demonstrate that Ca_o²⁺-induced filamin A cleavage occurs via a CaR- p115RhoGEF-calpain dependent pathway. Our data show that Ca_o²⁺ via CaR- mediated signaling induces filamin A cleavage and promotes the migration in AR-deficient and highly metastatic prostate cancer cells.

Differential protein expression profile in the hypothalamic GT1-7 cell line after exposure to anabolic androgenic steroids

The abuse of anabolic androgenic steroids (AAS) has been considered a major public health problem during decades. Supraphysiological doses of AAS may lead to a variety of neuroendocrine problems. Precisely, the hypothalamic-pituitary-gonadal (HPG) axis is one of the body systems that is mainly influenced by steroidal hormones. Fluctuations of the hormonal milieu result in alterations of reproductive function, which are made through changes in hypothalamic neurons expressing gonadotropin-releasing hormone (GnRH). In fact, previous studies have shown that AAS modulate the activity of these neurons through steroid-sensitive afferents. To increase knowledge about the cellular mechanisms induced by AAS in GnRH neurons, we performed proteomic analyses of the murine hypothalamic GT1-7 cell line after exposure to 17α-methyltestosterone (17α-meT; 1 μM). These cells represent a good model for studying regulatory processes because they exhibit the typical characteristics of GnRH neurons, and respond to compounds that modulate GnRH in vivo. Two-dimensional difference in gel electrophoresis (2D-DIGE) and mass spectrometry analyses identified a total of 17 different proteins that were significantly affected by supraphysiological levels of AAS. Furthermore, pathway analyses showed that modulated proteins were mainly associated to glucose metabolism, drug detoxification, stress response and cell cycle. Validation of many of these proteins, such as GSTM1, ERH, GAPDH, PEBP1 and PDIA6, were confirmed by western blotting. We further demonstrated that AAS exposure decreased expression of estrogen receptors and GnRH, while two important signaling pathway proteins p-ERK, and p-p38, were modulated. Our results suggest that steroids have the capacity to directly affect the neuroendocrine system by modulating key cellular processes for the control of reproductive function.

Sex differences in vascular physiology and pathophysiology: estrogen and androgen signaling in health and disease

Sex differences between women and men are often overlooked and underappreciated when studying the cardiovascular system. It has been long assumed that men and women are physiologically similar, and this notion has resulted in women being clinically evaluated and treated for cardiovascular pathophysiological complications as men. Currently, there is increased recognition of fundamental sex differences in cardiovascular function, anatomy, cell signaling, and pathophysiology. The National Institutes of Health have enacted guidelines expressly to gain knowledge about ways the sexes differ in both normal function and diseases at the various research levels (molecular, cellular, tissue, and organ system). Greater understanding of these sex differences will be used to steer future directions in the biomedical sciences and translational and clinical research. This review describes sex-based differences in the physiology and pathophysiology of the vasculature, with a special emphasis on sex steroid receptor (estrogen and androgen receptor) signaling and their potential impact on vascular function in health and diseases (e.g., atherosclerosis, hypertension, peripheral artery disease, abdominal aortic aneurysms, cerebral aneurysms, and stroke).

Androgen receptor dysfunction as a prevalent manifestation in young male carriers of a FLNA gene mutation

Androgenic actions require the proper signal transmission by the androgen receptor (AR), a nuclear transcription factor. This is initially located in the cell cytoplasm and should translocates to the nucleus to interact with DNA. AR functional impairment causes diverse blockage degrees of androgenic steroid action, known as androgen insensitivity syndromes. Filamin A, a protein coded by the FLNA gene, is a co-activator of various cytoplasmic factors, including AR. The mutational inactivation of the FLNA gene induces insufficiency of translocation and activation of AR. Consequently, it causes a developmental disorder of the male gonad and hypogonadism, similar to those observed in partial androgen insensitivity. We report two brothers carrying a loss-of-function mutation of FNLA with gonadal differentiation disorder and hypospadias. Specific staining for AR shows almost an absolute absence of these receptors in the testicular tissue. This association recommends investigating a possible mutational inactivation of the FLNA gene in patients with cryptorchidism and epididymo-testicular dissociation. The study is especially indicated when the family history, more often that of the mother, is suggestive. Likewise, growth and gonadal development of all male patients carrying this genetic trait should be monitored since childhood.

Non-Genomic Actions of the Androgen Receptor in Prostate Cancer

Androgen receptor (AR) is a validated drug target for prostate cancer based on its role in proliferation, survival, and metastases of prostate cancer cells. Unfortunately, despite recent improvements to androgen deprivation therapy and the advent of better antiandrogens with a superior affinity for the AR ligand-binding domain (LBD), most patients with recurrent disease will eventually develop lethal metastatic castration-resistant prostate cancer (CRPC). Expression of constitutively active AR splice variants that lack the LBD contribute toward therapeutic resistance by bypassing androgen blockade and antiandrogens. In the canonical pathway, binding of androgen to AR LBD triggers the release of AR from molecular chaperones which enable conformational changes and protein-protein interactions to facilitate its nuclear translocation where it regulates the expression of target genes. However, preceding AR function in the nucleus, initial binding of androgen to AR LBD in the cytoplasm may already initiate signal transduction pathways to modulate cellular proliferation and migration. In this article, we review the significance of signal transduction pathways activated by rapid, non-genomic signaling of the AR during the progression to metastatic CRPC and put into perspective the implications for current and novel therapies that target different domains of AR.

Extranuclear partners of androgen receptor: at the crossroads of proliferation, migration, and neuritogenesis

In this review, we focus on the role played by the protein partners of ligand-activated extranuclear androgen receptor (AR) in the final effects of hormone action, such as proliferation, migration, and neuritogenesis. The choice of AR partner, at least in part, depends on cell type. Androgen-activated receptor directly associates with cytoplasmic Src tyrosine kinase in epithelial cells, whereas in mesenchymal and neuronal cells, it prevalently interacts with filamin A. In the former, proliferation represents the final hormonal outcome, whereas in the latter, either migration or neuritogenesis, respectively, occurs. Furthermore, AR partner filamin A is replaced with Src when mesenchymal cells are stimulated with very low androgen concentrations. Consequently, the migratory effect is replaced by mitogenesis. Use of peptides that prevent receptor/partner assembly abolishes the effects that are dependent on their association and offers new therapeutic approaches to AR-related diseases. Perturbation of migration is often associated with metastatic spreading in cancer. In turn, cell cycle aberration causes tumors to grow faster, whereas toxic signaling triggers neurodegenerative events in the CNS. Here, we provide examples of new tools that interfere in rapid androgen effects, including migration, proliferation, and neuronal differentiation, together with their potential therapeutic applications in AR-dependent diseases-mainly prostate cancer and neurodegenerative disorders.-Castoria, G., Auricchio, F., Migliaccio, A. Extranuclear partners of androgen receptor: at the crossroads of proliferation, migration, and neuritogenesis.

Prostate cancer stem cells: the role of androgen and estrogen receptors

Prostate cancer is one of the most commonly diagnosed cancers in men, and androgen deprivation therapy still represents the primary treatment for prostate cancer patients. This approach, however, frequently fails and patients develop castration-resistant prostate cancer, which is almost untreatable.

Cancer cells are characterized by a hierarchical organization, and stem/progenitor cells are endowed with tumor-initiating activity. Accumulating evidence indicates that prostate cancer stem cells lack the androgen receptor and are, indeed, resistant to androgen deprivation therapy. In contrast, these cells express classical (α and/or β) and novel (GPR30) estrogen receptors, which may represent new putative targets in prostate cancer treatment.

In the present review, we discuss the still-debated mechanisms, both genomic and non-genomic, by which androgen and estradiol receptors (classical and novel) mediate the hormonal control of prostate cell stemness, transformation, and the continued growth of prostate cancer. Recent preclinical and clinical findings obtained using new androgen receptor antagonists, anti-estrogens, or compounds such as enhancers of androgen receptor degradation and peptides inhibiting non-genomic androgen functions are also presented. These new drugs will likely lead to significant advances in prostate cancer therapy.

Lentiviral vector-mediated insertional mutagenesis screen identifies genes that influence androgen independent prostate cancer progression and predict clinical outcome

Prostate cancer (PC) is the second leading cause of cancer related deaths in US men. Androgen deprivation therapy (ADT) improves clinical outcome, but tumors often recur and progress to androgen independent prostate cancer (AIPC) which no longer responds to ADT. The progression to AIPC is due to genetic alterations that allow PC cancer cells to grow in the absence of androgen. Here we performed an insertional mutagenesis screen using a replication-incompetent lentiviral vector (LV) to identify the genes that promote AIPC in an orthotopic mouse model. Androgen sensitive PC cells, LNCaP, were mutagenized with LV and injected into the prostate of male mice. After tumor development, mice were castrated to select for cells that proliferate in the absence of androgen. Proviral integration sites and nearby dysregulated genes were identified in tumors developed in an androgen deficient environment. Using publically available datasets, the expression of these candidate androgen independence genes in human PC tissues were analyzed. A total of 11 promising candidate AIPC genes were identified: GLYATL1, FLNA, OBSCN, STRA13, WHSC1, ARFGAP3, KDM2A, FAM83H, CLDN7, CNOT6, and B3GNT9. Seven out the 11 candidate genes; GLYATL1, OBSCN, STRA13, KDM2A, FAM83H, CNOT6, and B3GNT6, have not been previously implicated in PC. An in vitro clonogenic assay showed that knockdown of KDM2A, FAM83H, and GLYATL1 genes significantly inhibited the colony forming ability of LNCaP cells. Additionally, we showed that a combination of four genes, OBSCN, FAM83H, CLDN7, and ARFGAP3 could significantly predicted the recurrence risk in PC patients after prostatectomy (P = 5.3 × 10-5 ). © 2015 Wiley Periodicals, Inc.

Analysis of TMEFF2 allografts and transgenic mouse models reveals roles in prostate regeneration and cancer

BACKGROUND

Previous results from our lab indicate a tumor suppressor role for the transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) in prostate cancer (PCa). Here, we further characterize this role and uncover new functions for TMEFF2 in cancer and adult prostate regeneration.

METHODS

The role of TMEFF2 was examined in PCa cells using Matrigel(TM) cultures and allograft models of PCa cells. In addition, we developed a transgenic mouse model that expresses TMEFF2 from a prostate specific promoter. Anatomical, histological, and metabolic characterizations of the transgenic mouse prostate were conducted. The effect of TMEFF2 in prostate regeneration was studied by analyzing branching morphogenesis in the TMEFF2-expressing mouse lobes and alterations in branching morphogenesis were correlated with the metabolomic profiles of the mouse lobes. The role of TMEFF2 in prostate tumorigenesis in whole animals was investigated by crossing the TMEFF2 transgenic mice with the TRAMP mouse model of PCa and analyzing the histopathological changes in the progeny.

RESULTS

Ectopic expression of TMEFF2 impairs growth of PCa cells in Matrigel or allograft models. Surprisingly, while TMEFF2 expression in the TRAMP mouse did not have a significant effect on the glandular prostate epithelial lesions, the double TRAMP/TMEFF2 transgenic mice displayed an increased incidence of neuroendocrine type tumors. In addition, TMEFF2 promoted increased branching specifically in the dorsal lobe of the prostate suggesting a potential role in developmental processes. These results correlated with data indicating an alteration in the metabolic profile of the dorsal lobe of the transgenic TMEFF2 mice.

CONCLUSIONS

Collectively, our results confirm the tumor suppressor role of TMEFF2 and suggest that ectopic expression of TMEFF2 in mouse prostate leads to additional lobe-specific effects in prostate regeneration and tumorigenesis. This points to a complex and multifunctional role for TMEFF2 during PCa progression.

The Androgen Receptor Antagonizes Wnt/β-Catenin Signaling in Epidermal Stem Cells

Activation of Wnt/β-catenin signaling in adult mouse epidermis leads to expansion of the stem cell compartment and redirects keratinocytes in the interfollicular epidermis and sebaceous glands (SGs) to differentiate along the hair follicle (HF) lineages. Here we demonstrate that during epidermal development and homeostasis there is reciprocal activation of the androgen receptor (AR) and β-catenin in cells of the HF bulb. AR activation reduced β-catenin-dependent transcription, blocked β-catenin-induced induction of HF growth, and prevented β-catenin-mediated conversion of SGs into HFs. Conversely, AR inhibition enhanced the effects of β-catenin activation, promoting HF proliferation and differentiation, culminating in the formation of benign HF tumors and a complete loss of SG identity. We conclude that AR signaling has a key role in epidermal stem cell fate selection by modulating responses to β-catenin in adult mouse skin.

Pathway analysis supports association of nonsyndromic cryptorchidism with genetic loci linked to cytoskeleton-dependent functions

STUDY QUESTION

What are the genetic loci that increase susceptibility to nonsyndromic cryptorchidism, or undescended testis?

SUMMARY ANSWER

A genome-wide association study (GWAS) suggests that susceptibility to cryptorchidism is heterogeneous, with a subset of suggestive signals linked to cytoskeleton-dependent functions and syndromic forms of the disease.

WHAT IS KNOWN ALREADY

Population studies suggest moderate genetic risk of cryptorchidism and possible maternal and environmental contributions to risk. Previous candidate gene analyses have failed to identify a major associated locus, although variants in insulin-like 3 (INSL3), relaxin/insulin-like family peptide receptor 2 (RXFP2) and other hormonal pathway genes may increase risk in a small percentage of patients.

STUDY DESIGN, SIZE, DURATION

This is a case-control GWAS of 844 boys with nonsyndromic cryptorchidism and 2718 control subjects without syndromes or genital anomalies, all of European ancestry.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All boys with cryptorchidism were diagnosed and treated by a pediatric specialist. In the discovery phase, DNA was extracted from tissue or blood samples and genotyping performed using the Illumina HumanHap550 and Human610-Quad (Group 1) or OmniExpress (Group 2) platform. We imputed genotypes genome-wide, and combined single marker association results in meta-analyses for all cases and for secondary subphenotype analyses based on testis position, laterality and age, and defined genome-wide significance as P = 7 × 10(-9) to correct for multiple testing. Selected markers were genotyped in an independent replication group of European cases (n = 298) and controls (n = 324). We used several bioinformatics tools to analyze top (P < 10(-5)) and suggestive (P < 10(-3)) signals for significant enrichment of signaling pathways, cellular functions and custom gene lists after multiple testing correction.

MAIN RESULTS AND THE ROLE OF CHANCE

In the full analysis, we identified 20 top loci, none reaching genome-wide significance, but one passing this threshold in a subphenotype analysis of proximal testis position (rs55867206, near SH3PXD2B, odds ratio = 2.2 (95% confidence interval 1.7, 2.9), P = 2 × 10(-9)). An additional 127 top loci emerged in at least one secondary analysis, particularly of more severe phenotypes. Cytoskeleton-dependent molecular and cellular functions were prevalent in pathway analysis of suggestive signals, and may implicate loci encoding cytoskeletal proteins that participate in androgen receptor signaling. Genes linked to human syndromic cryptorchidism, including hypogonadotropic hypogonadism, and to hormone-responsive and/or differentially expressed genes in normal and cryptorchid rat gubernaculum, were also significantly overrepresented. No tested marker showed significant replication in an independent population. The results suggest heterogeneous, multilocus and potentially multifactorial susceptibility to nonsyndromic cryptorchidism.

LIMITATIONS, REASONS FOR CAUTION

The present study failed to identify genome-wide significant markers associated with cryptorchidism that could be replicated in an independent population, so further studies are required to define true positive signals among suggestive loci.

WIDER IMPLICATIONS OF THE FINDINGS

As the only GWAS to date of nonsyndromic cryptorchidism, these data will provide a basis for future efforts to understand genetic susceptibility to this common reproductive anomaly and the potential for additive risk from environmental exposures.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by R01HD060769 (the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD)), P20RR20173 (the National Center for Research Resources (NCRR), currently P20GM103464 from the National Institute of General Medical Sciences (NIGMS)), an Institute Development Fund to the Center for Applied Genomics at The Children's Hospital of Philadelphia, and Nemours Biomedical Research. The authors have no competing interests to declare.