Search Results (70)

Growth hormone-releasing hormone (GHRH) antagonists have displayed anti-neoplastic activity against a multitude of cancers in vitro, as well as in vivo, via xenografted tumors in nude mice. Following a successful demonstration of GHRH antagonists treating non-Hodgkin’s lymphoma and the discovery of GHRH mRNA and peptide products in immune cells, GHRH antagonism was explored in acute myeloid leukemia (AML), a disease characterized by a malignant expansion of immature myeloid progenitors, and poor 5-year survival. Targeted therapies have yielded breakthroughs in treatment response and overall survival, such as all-trans retinoic acid/arsenic trioxide (ATRA/ATO) for acute promyelocytic leukemia (APL), or FLT3 inhibitors, IDH inhibitors, and menin inhibitors for AML harboring actionable genetic lesions. However, therapeutic resistance remains a major barrier to durable remission. GHRH receptor (GHRH-R) has been reported in several experimental models of AML, including drug-resistant sublines. Significant time- and dose-dependent reduction in leukemic growth was observed in vitro and in vivo following MIA-602 treatment. FLT3 inhibitor resistance has been associated with activation of PI3K/AKT, ERK/MAPK, inflammatory, stromal, and apoptotic escape pathways. The documented effects of GHRH-R antagonism raise the possibility that it could influence signaling networks relevant to therapeutic resistance in AML. This hypothesis remains speculative; to date no studies have stratified AML by FLT3 status in the context of GHRH-R expression or GHRH antagonism, and there is currently no evidence that MIA-602 directly alters FLT3 receptor signaling or inhibitor sensitivity. Full article

Preeclampsia (PE) is a severe pregnancy-specific hypertensive disorder characterized by immune microenvironment dysregulation at the maternal–fetal interface, with decidual macrophage phenotypic imbalance being a key pathological feature. The Ghrelin/growth hormone secretagogue receptor-1a (GHSR-1a) axis exerts immunomodulatory and anti-inflammatory effects, but its role in regulating decidual macrophage infiltration and phenotypic marker expression in PE remains unclear. In this study, we first detected the expression of the Ghrelin/GHSR-1a axis in decidual tissues from 10 healthy pregnant women and 12 PE patients via immunohistochemistry (IHC). We then established a lipopolysaccharide (LPS)-induced PE-like rat model to investigate the axis’s functional role and underlying mechanisms. Intriguingly, clinical analysis revealed a severity-dependent compensatory escalation of the Ghrelin/GHSR-1a axis in PE decidual tissues, potentially representing an endogenous antagonistic response to pregnancy-associated pathological stress. In the animal model, exogenous Ghrelin supplementation reversed LPS-induced PE-like phenotypes, including hypertension, proteinuria, fetal growth restriction (FGR), and placental dysfunction, and alleviated pathological damage to the maternal liver, kidney, and placenta. Mechanistically, Ghrelin modulated decidual macrophage phenotypic marker expression by downregulating the M1 marker CD86 and upregulating the M2 marker CD163 and promoted trophoblast invasion and spiral artery remodeling by restoring laminin, α-cytokeratin 7 (α-CK7), and α-smooth muscle actin (α-SMA) expression in placental tissue. All protective effects of Ghrelin were abrogated by co-administration of D-lys-3-GHRP-6, a specific GHSR-1a antagonist, confirming the dependence on the Ghrelin/GHSR-1a axis. Collectively, our findings suggest that the Ghrelin/GHSR-1a axis is compensatorily upregulated in PE and may exert a protective role by regulating decidual macrophage phenotypic marker expression and improving placental function, providing preliminary evidence that this axis merits further investigation as a potential research target for PE. Full article

Steroid-sensitive cancers (e.g., breast, ovarian, uterine, and prostate cancers) are difficult to control and frequently metastasize to lymph nodes, bone, or lung. Although endocrine research has greatly advanced our identification of the direct roles of steroid sex hormones such as androgens and estrogens on tumor cells in promoting metastasis or recurrence (e.g., treatment with gonadotropin releasing hormone agonists/antagonists, aromatase inhibitors, and estrogen and androgen receptor antagonists), mechanistic insight regarding indirect effects of steroid hormones, including how the innate immune system responds to cancer and is influenced by steroid hormones, is lacking. Despite technological advances in engineering more robust adaptive immunity to combat tumor growth (e.g., CART or checkpoint inhibitors), there remains a relative lack of investigation into the role of innate immunity as a key defense system. Here we discuss recent studies that highlight the significance of neutrophils and their response to tumorigenic conditions with or without steroid hormones in animal models of cancer. We will describe relationships between steroid hormones and neutrophils, with a specific focus on neutrophil extracellular traps (NETs), and how these interactions modulate tumor growth and invasion. Together, these data indicate that combinatorial regulation of both innate and adaptive immunity in the context of tumorigenesis may improve outcomes in cancer therapies. Full article

Lung cancer (LC) remains the leading cause of cancer-related death in the United States despite advances in therapy. Growth hormone (GH) action has been implicated in tumor progression and therapy resistance across multiple cancers, but its role in LC, particularly non-small cell lung cancer (NSCLC), remains poorly defined. In cancer cells, GH promotes chemoresistance through upregulation of drug-efflux pumps, induction of epithelial-to-mesenchymal transition (EMT), and inhibition of apoptosis. Notably, GH receptor (GHR) expression is significantly elevated in NSCLC compared to normal lung tissue, suggesting a potential therapeutic opportunity. In this study, we investigated the impact of GH action on therapy resistance and tumor progression using integrated transcriptomic analyses and in vitro experiments. Analyses of transcriptomic data from NSCLC patients revealed that high tumoral GHR expression correlates with reduced overall survival, and with upregulation of genes involved in distinct therapy refractory pathways. Our in vitro studies demonstrated that GH promotes chemoresistance in NSCLC cell lines through activation of ABC transporters and EMT pathways, whereas GHR antagonism with the GH receptor antagonist, pegvisomant, effectively counteracts these effects and improves chemotherapy efficacy significantly. Together, our findings identify GHR signaling as a contributor to aggressive and therapy-resistant phenotypes in NSCLC in vitro and suggest that GHR antagonism may enhance chemotherapy sensitivity. These results provide a rationale for further in vivo and mechanistic studies to evaluate the therapeutic potential of targeting GHR in NSCLC. Full article

Ovarian aging (OA) results from the senescence of different cell types present in the ovary, decreasing female fertility and quality of life and augmenting the risk of a variety of fertility-unrelated pathological conditions. The changes observed in the ovarian cells are accompanied by changes occurring in various elements of the hypothalamic–pituitary–ovarian (HPO) axis, the complex endocrine system that regulates the female reproductive cycle. Issues pertaining to the HPO axis have been addressed in animal models via hormonal treatments with preparations inhibiting ovarian follicular recruitment at the level of the receptors of gonadotropin-releasing hormone (GnRH)-secreting neurons, mainly acting on glutamate- and gamma-aminobutyric acid (GABA)-driven signaling. GnRH agonists and antagonists have also been used in women exposed to chemotherapeutics. HPO-independent OA can be delayed through the administration of different antioxidants and mitochondria-protecting agents, among which melatonin has been shown to be particularly useful. Other therapeutic approaches used with success in women include hormonal and growth factor (GF) modulators, such as growth hormone (GH), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factors (VEGF), and dehydroepiandrosterone (DHEA), and the development of patient-tailored combination-based therapies (IGF-1 + VEGF + DHEA) has also been suggested. Intraovarian injection of autologous platelet-rich plasma (PRP), mitochondrial donation through pronuclear transfer, and ovarian tissue cryopreservation and autotransplantation have also yielded promising results in women, and their use can preserve not only fertility but also the ovarian endocrine function. Personalized mixtures of specific agents (desatinib, quercetin, rapamycin, metformin, resveratrol, melatonin, and coenzyme Q10) targeting different cell types in the ovary are currently under investigation. Overall, this review aims to present a global view of the subject, uniting the physiological and molecular background of this pathology with the history and development of potential treatment strategies and new perspectives in this domain. As such, this study may be helpful both to clinicians facing problems resulting from OA and to researchers pursuing further developments in this field. Full article

Our understanding of Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor 1a (GHSR1a), has expanded from considering it to be a “hunger hormone” to a pleiotropic regulator of whole-body physiology. This review synthesizes the current advances spanning ghrelin biogenesis, signaling, and systems biology. Physiologically, preproghrelin processing and O-acylation by ghrelin O-acyltransferase (GOAT) generate acyl-ghrelin, a high-potency GHSR1a agonist; des-acyl ghrelin predominates in circulation and exerts context-dependent, GHSR1a-independent, or low-potency effects, while truncated “mini-ghrelins” can act as competitive antagonists. The emergence of synthetic ligands, agonists, antagonists, and reverse-agonists has provided the necessary tools to decipher GHSR1a activity. Recent cryo-EM structures of GHSR1a with peptide and small-molecule ligands reveal a bipartite binding pocket and provide a framework for biased signaling, constitutive activity, and receptor partner selectivity. Beyond the regulation of feeding and growth-hormone release, ghrelin modulates glucose homeostasis, gastric secretion and motility, cardiovascular tone, bone remodeling, renal hemodynamics, and innate immunity. Ghrelin broadly dampens pro-inflammatory responses and promotes reparative macrophage phenotypes. In the emerging scholarship on ghrelin’s activity in the central nervous system, ghrelin has been found to influence neuroprotection, stress reactivity, and sleep architecture, and has also been implicated in depression, Alzheimer’s disease, and substance-abuse disorders. Practical and transitional aspects are also highlighted in the literature: approaches for ghrelin stabilization; recent GHSR1a agonists/antagonists and inverse agonists findings; LEAP-2-based strategies; and emerging GOAT inhibitors. Together, structural insights and pathway selectivity position the ghrelin system as a druggable axis for the management of inflammatory diseases, neuropsychiatric and addiction conditions, and for obesity treatment in the post-GLP-1 receptor agonist era. Full article

Melanoma is one of the most aggressive skin cancers, with increasing rates of occurrence. Although it has not traditionally been considered hormonally driven, recent evidence links androgen receptor (AR) signaling to important aspects of melanoma biology, including tumor growth, metastasis, immune evasion, and resistance to therapy. Mechanistically, AR promotes melanoma progression by activating a pro-metastatic gene program, suppressing anti-tumor immune responses, and altering the tumor microenvironment. Additionally, emerging data indicate AR’s involvement in resistance to chemotherapy and immune-based therapies. This review provides a comprehensive overview of AR’s intricate role in melanoma, focusing on its molecular mechanisms, its impact on immune evasion and therapy resistance, and its potential clinical applications. We also assess AR-targeted strategies, including androgen deprivation therapy and AR antagonists, to improve the effectiveness of chemotherapy, targeted therapy, and immunotherapy. Understanding AR’s role in melanoma could lead to new treatment options, particularly for sex-specific patient groups. Full article

Growth hormone (GH) signaling has been implicated in tumor progression and therapy resistance across multiple cancer types, yet its role in bladder cancer remains largely unexplored. In this study, we investigated the impact of GH and its receptor (GHR) on therapy resistance and disease progression in urothelial carcinoma (UC) through integrated transcriptomic and in vitro analyses. Transcriptomic profiling of The Cancer Genome Atlas bladder cancer cohort revealed that high tumoral GHR expression was associated with differential upregulation of genes involved in drug efflux, epithelial-to-mesenchymal transition (EMT), and extracellular matrix (ECM) remodeling. Notably, elevated GHR levels correlated with significantly reduced overall survival in patients with UC. In parallel, in vitro experiments demonstrated that GH promotes chemoresistance in UC cell lines via upregulation of ATP-binding cassette-containing (ABC) transporters and activation of EMT. GH also modulated ECM-remodeling-associated genes in a chemotherapy-dependent manner, including matrix metalloproteinases and tissue inhibitors of metalloproteinases. Importantly, these effects were abrogated by Pegvisomant, a GHR antagonist, indicating the functional relevance of GH/GHR signaling in the mediation of these phenotypes. Collectively, our findings support a mechanistic role for GH signaling in driving therapy resistance and tumor aggressiveness in bladder cancer and suggest GHR antagonism as a potential therapeutic strategy to improve treatment outcomes. Full article

L-type lectin receptor-like kinases (L-LecRLKs) play key roles in plant responses to environmental stresses and the regulation of growth and development. However, comprehensive studies of the L-LecRLK gene family in wheat (Triticum aestivum L.) are still limited. In this study, 248 L-LecRLK candidate genes were identified in wheat, which is the largest number reported in any species to date. Phylogenetic analysis grouped these genes into four clades (I–IV), with Group IV exhibiting significant monocot-specific expansion. Gene duplication analysis revealed that both whole-genome/segmental and tandem duplications contributed to family expansion, while Ka/Ks ratio analysis suggested that the genes have undergone strong purifying selection. The TaL-LecRLK genes displayed diverse exon-intron structures and conserved motif compositions. Promoter analysis revealed a cis-element associated with hormone signaling and abiotic stress responses. Transcriptome profiling showed that TaL-LecRLKs exhibit tissue- and stage-specific expression patterns. RNA-Seq data revealed that, under drought and heat stress conditions, TaL-LecRLK35-3D and TaL-LecRLK67-6B exhibited synergistic expression patterns, whereas TaL-LecRLK67-6A demonstrated antagonistic expression. A qRT-PCR further demonstrated that six TaL-LecRLKs may function through ABA-independent regulatory mechanisms. These findings provide valuable gene candidates for stress-resistant wheat breeding and shed light on the evolution and functional diversity of L-LecRLKs in plants. Full article

Background. Antagonists of GHRH have experimental therapeutic value, but as single agents are not likely to improve clinical outcomes, especially in advanced prostate cancer resistant to androgen deprivation therapy. Our objective is to identify anti-cancer drugs that, in combination with MIA-602 or -690 GHRH antagonists, increase cell death in all types of prostate cancer. Methods/Results. We identified inhibitors of PI3Kα or PI3Kβ that consistently increased cell death when combined with MIA-602/690. The PI3K family is critical in mediating upstream signals from receptors to downstream AKT/mTOR signaling pathways and has an important role in cancer progression. The results revealed that MIA-602/690 alone decreased androgen receptors and likely enhanced PI3K (negative feedback), which was then countered by the addition of PI3K inhibitors. Furthermore, the MIA-602/690 + PI3K inhibitor combination affected multiple signaling pathways, including apoptosis (anti-apoptotic Mcl-1L switching to pro-apoptotic Mcl-1S), proliferation (E2F1, cyclin A), PI3Kα/β, AKT, and ERK. Similar results were obtained with a more clinically relevant acetate salt form of MIA-602/690. The identification of PI3K as a drug target for prostate cancer is significant because PTEN (negative regulator of PI3K) loss of function occurs in 40–50% and PIK3CA mutation/amplification occurs in 60% of prostate cancer patients, leading to a poor prognosis. Conclusion. The ability of the MIA-602/690 + PI3K inhibitor combination to alter multiple signaling pathways may weaken the activation of adaptive mechanisms resulting from each drug and improve efficacy. Full article

Growth hormone-releasing hormone (GHRH) antagonists exert antitumor functions in different experimental cancers. However, their role in combination with radiotherapy in non-small cell lung cancer (NSCLC) remains unknown. Therefore, we investigated the radiosensitizing effect of GHRH antagonists in NSCLC. A549 and H522 NSCLC cell lines were exposed to ionizing radiation (IR) and GHRH antagonists MIA-602 and MIA-690, either individually or in combination. Cell viability and proliferation were evaluated by MTT, BrdU, flow cytofluorimetry, and clonogenic assays; gene and protein expression, signaling pathways, and apoptosis were analyzed by real-time PCR, Western blot, annexin staining, and caspase-3 assay. GHRH antagonists showed antitumor effects alone and potentiated IR-induced inhibition of cell viability and proliferation. The combination of MIA-690 and IR decreased the expression of GHRH receptor, its oncogenic splice variant 1, and IGF1 mRNA levels. Additionally, cell cycle inhibitors and proapoptotic markers were upregulated, whereas cyclins, oncogenic MYC, and the antiapoptotic protein Bcl-2 were downregulated. Radioresistance was prevented by MIA-690, which also blunted epithelial–mesenchymal transition by enhancing E-cadherin and reducing mesenchymal, oxidative, and proangiogenic effectors. Finally, both MIA-602 and MIA-690 enhanced radiosensitivity in primary human NSCLC cells. These findings highlight the potential of GHRH antagonists as radiosensitizers in NSCLC treatment. Full article

Long-term treatment options for conventional chemo-endocrine therapy and molecular-pathway-based targeted therapy are associated with acquired therapy resistance and the emergence of drug-resistant cancer-initiating stem cell populations, leading to the progression of metastatic disease. These treatment options are based on the expression status of estrogen receptor-α (ER-α), progesterone receptor (PR) hormone receptors, and/or of human epidermal growth factor receptor-2 (HER-2). The breast cancer subtypes Luminal A, Luminal B, and HER-2-enriched express hormone/growth factor receptors and exhibit a favorable response to hormone receptor modulators and growth factor receptor antagonists. The triple-negative breast cancer subtype lacks the expression of hormone/growth factor receptors and responds only to cytotoxic conventional chemotherapy. The clinical limitations, due to the modest therapeutic responses of chemo-resistant cancer-initiating stem cells, emphasize the need for the identification of stem cells targeting testable alternatives for therapy-resistant breast cancer. Developed drug-resistant stem cell models exhibit upregulated expression of select cellular biomarker tumor spheroid (TS) formations and cluster of differentiation44 (CD44), DNA-binding protein (NANOG), and octamer-binding protein-4 (OCT-4) molecular biomarkers that represent novel experimentally modifiable quantitative endpoints. Naturally occurring dietary phytochemicals and nutritional herbs containing polyphenols, flavones, terpenes, saponins, lignans, and tannins have documented human consumption, lack systemic toxicity, lack phenotypic drug resistance, and exhibit preclinical efficacy. Constituent bioactive agents may provide testable stem cell-targeting alternatives. The present report provides an overview of (i) clinically relevant cellular models and drug-resistant cancer stem cell models for breast cancer subtypes, (ii) evidence for preclinical efficacy and mechanistic leads for natural phytochemicals and nutritional herbs, and (iii) the potential for the stem cell-targeting efficacy of natural bioactive agents as testable drug candidates for therapy-resistant breast cancer. Full article

Acromegaly is a rare endocrine disorder caused by excessive growth hormone (GH) production, due, in the vast majority of cases, to the presence of a GH-secreting pituitary tumour. The chronic elevation of GH and the resulting high circulating levels of insulin-like growth factor-1 (IGF-1) cause the characteristic tissue overgrowth and a number of associated comorbidities, including several metabolic changes, such as glucose intolerance and overt diabetes mellitus (DM). Elevated GH concentrations directly attenuate insulin signalling and stimulate lipolysis, decreasing glucose uptake in peripheral tissues, thus leading to the development of impaired glucose tolerance and DM. Acromegaly treatment aims to normalize plasma GH and IGF-1 levels using surgery, medical treatment, or radiotherapy. The effect of the different medical therapies on glucose homeostasis varies. This literature review explores the impact of the currently available pharmacological therapies for acromegaly (first- and second-generation somatostatin receptor ligands, a GH receptor antagonist, and dopamine agonists) on glucose homeostasis. We also discuss the underlying biological mechanisms through which they impact glucose metabolism. Full article

The development of resistance remains the primary challenge in treating castration-resistant prostate cancer (CRPC). GHRH receptors (GHRH-R), which are coupled to G-proteins (GPCRs), can mediate EGFR transactivation, offering an alternative pathway for tumour survival. This study aimed to evaluate the effects of the GHRH-R antagonist MIA-690, in combination with the EGFR inhibitor Gefitinib, on cell viability, adhesion, gelatinolytic activity, and the cell cycle in advanced prostate cancer PC-3 cells. The findings demonstrate a synergistic effect between MIA-690 and Gefitinib, leading to the inhibition of cell viability, adhesion, and metalloprotease activity. Cell cycle analysis suggests that both compounds induce cell cycle arrest, both individually and in combination. Furthermore, similar effects of the GHRH-R antagonist MIA-690 combined with Gefitinib were observed in PC-3 tumours developed by subcutaneous injection in athymic nude mice 36 days post-inoculation. These results indicate that combined therapy with a GHRH-R antagonist and an EGFR inhibitor exerts a stronger antitumor effect compared to monotherapy by preventing transactivation between EGFR and GHRH-R in CRPC. Full article

Drug resistance in melanoma is a major hindrance in cancer therapy. Growth hormone (GH) plays a pivotal role in contributing to the resistance to chemotherapy. Knocking down or blocking the GH receptor has been shown to sensitize the tumor cells to chemotherapy. Extensive studies have demonstrated that exosomes, a subset of extracellular vesicles, play an important role in drug resistance by transferring key factors to sensitize cancer cells to chemotherapy. In this study, we explore how GH modulates exosomal cargoes from melanoma cells and their role in drug resistance. We treated the melanoma cells with GH, doxorubicin, and the GHR antagonist, pegvisomant, and analyzed the exosomes released. Additionally, we administered these exosomes to the recipient cells. The GH-treated melanoma cells released exosomes with elevated levels of ABC transporters (ABCC1 and ABCB1), N-cadherin, and MMP2, enhancing drug resistance and migration in the recipient cells. GHR antagonism reduced these exosomal levels, restoring drug sensitivity and attenuating migration. Overall, our findings highlight a novel role of GH in modulating exosomal cargoes that drive chemoresistance and metastasis in melanoma. This understanding provides insights into the mechanisms of GH in melanoma chemoresistance and suggests GHR antagonism as a potential therapy to overcome chemoresistance in melanoma treatment. Full article