Glucocorticoids represent the standard gold treatment of inflammation in asthmatic patients. More recently, H2S has been described to exert positive effect on this disease. Bearing in mind that an improved pharmacological activity and a reduced toxicity can be obtained through hybridization of different molecules, simultaneously modulating multiple targets, we designed and synthesized novel betamethasone 17-valerate and triamcinolone acetonide hybrids with well-known H2S-donor moieties. Synthesized compounds have been evaluated for the potential H2S-releasing profile both in cell-free environment and into the cytosol of bronchial smooth muscle cells (BSMCs). The two hybrids 4b and 5b were investigated by molecular modelling studies and results indicated that the steric accessibility of the isothiocyanate carbon atom can account for their different H2S releasing properties. Furthermore, the most promising derivatives 4b and 5b have been tested for inhibitory effect on mast cell degranulation and for the ability to induce cell membrane hyperpolarization in BSMCs. Significant inhibitory effect on mast cell degranulation was assessed, resulting to reduce β-hexosaminidase release more efficiently than the corresponding native drugs. Both compounds determined a massive membrane hyperpolarization of BSMCs and proved to be 4-fold more effective compared to reference compound NS1619. These effects represent an enrichment of the pharmacological activity of the native drugs.

Industrial hemp is characterized by a huge amount of by-products, such as inflorescences, that may represent high-quality sources of biomolecules with pharmaceutical interest. In the present study, we have evaluated the phytochemical profile, including terpene and terpenophenolic compounds, of the essential oils (EOs) of Futura 75, Carmagnola selezionata and Eletta campana hemp varieties. The EOs were also tested for antifungal properties toward Trichophyton mentagrophytes, Trichophyton rubrum, Arthroderma crocatum, Arthroderma quadrifidum, Arthroderma gypseum, Arthroderma curreyi, and Arthroderma insingulare. In parallel, we investigated the inhibitory effects of the EOs against tyrosinase, and the production of prostaglandin E2 in isolated mouse skin exposed to hydrogen peroxide. In human H1299 lung adenocarcinoma cells, we also evaluated the influence of the EOs on the gene expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2), which are involved in SARS-CoV-2 entry in human host. E-caryophyllene and α-pinene were the prominent terpenes in the EOs, whereas the cannabidiolic acid was the terpenophenol present at higher concentration. The EOs inhibited the growth of all tested dermatophytes species. In isolated skin specimens, EOs prevented the hydrogen-peroxide-induced synthesis of prostaglandin E2, consistent with the intrinsic antityrosinase activity. Finally, in H1299 cells, all tested EOs reduced the gene expression of ACE-2 and TMPRSS2, as well. Therefore, the present findings highlight the rationale for the use of the present EOs against infectious diseases.

Growth hormone-releasing hormone (GHRH) is a potent stimulator of growth hormone (GH) secretion from the pituitary gland. Although GHRH is essential for the growth of immune cells, the regulatory effects of its antagonist in granulomatous disease remain unknown.

Mentha spicata is one of the most popular species in the genus, and it is of great interest as a gastrointestinal and sedative agent in the folk medicine system. In this study, different M. spicata extracts, obtained by the use of four solvents (hexane, chloroform, acetone and acetone/water) were chemically characterized using HPLC-ESI-MS n, which allowed for identification of 27 phenolic compounds. The extracts' antioxidant and enzyme inhibitory properties were investigated. In addition, neuroprotective effects were evaluated in hypothalamic HypoE22 cells, and the ability of the extracts to prevent the hydrogen peroxide-induced degradation of dopamine and serotonin was observed. The best antioxidant effect was achieved for all the extraction methods using acetone/water as a solvent. These extracts were the richest in acacetin, eriodictyol, hesperidin, sagerinic acid, naringenin, luteolin, chlorogenic acid, chrysoeriol and apigenin. The intrinsic antioxidant and enzyme inhibition properties of the acetone/water extract could also explain, albeit partially, its efficacy in preventing prostaglandin E2 overproduction and dopamine depletion (82.9% turnover reduction) in HypoE22 cells exposed to hydrogen peroxide. Thus, our observations can provide a scientific confirmation of the neuromodulatory and neuroprotective effects of M. spicata.

Pollen extract represents an innovative approach for the management of the clinical symptoms related to prostatitis and pelvic inflammatory disease (PID). In this context, the aims of the present work were to analyze the phenolic composition of a hydroalcoholic extract of PollenAid Plus soft gel capsules, and to evaluate the extract's cytotoxic effects, in human prostate cancer PC3 cells and human ovary cancer OVCAR-3 cells. Additionally, protective effects were investigated in isolated prostate and ovary specimens exposed to lipopolysaccharide (LPS). The phytochemical investigation identified catechin, chlorogenic acid, gentisic acid, and 3-hydroxytyrosol as the prominent phenolics. The extract did not exert a relevant cytotoxic effect on PC3 and OVCAR-3 cells. However, the extract showed a dose-dependent inhibition of pro-inflammatory IL-6 and TNF-α gene expression in prostate and ovary specimens, and the extract was effective in preventing the LPS-induced upregulation of CAT and SOD gene expression, which are deeply involved in tissue antioxidant defense systems. Finally, a docking approach suggested the capability of catechin and chlorogenic acid to interact with the TRPV1 receptor, playing a master role in prostate inflammation. Overall, the present findings demonstrated anti-inflammatory and antioxidant effects of this formulation; thus, suggesting its capability in the management of the clinical symptoms related to prostatitis and PID.

Sirtuin 1 (SIRT1) is a NAD+-dependent deacetylase implicated in various biological and pathological processes, including cancer, diabetes, and cardiovascular diseases. In recent years, SIRT1-activating compounds have been demonstrated to exert cardioprotective effects. Therefore, this enzyme has become a feasible target to treat cardiovascular diseases, and many SIRT1 activators, of a natural or synthetic origin, have been identified. In the present work, we developed thiazole-based SIRT1 activators, which showed remarkably higher SIRT1 activation potencies compared with those of the reference compound resveratrol when tested in enzymatic assays. Thiazole 8, a representative compound of this series, was also subjected to further pharmacological investigations, where it was proven to reduce myocardial damage induced by an in vivo occlusion/reperfusion event, thus confirming its cardioprotective properties. In addition, the cardioprotective effect of compound 8 was significantly higher than that of resveratrol. Molecular modeling studies suggest the binding mode of these derivatives within SIRT1 in the presence of the p53-AMC peptide. These promising results could pave the way to further expand and optimize this chemical class of new and potent SIRT1 activators as potential cardioprotective agents.

Activation of peroxisome proliferator-activated receptors (PPARs) not only regulates multiple metabolic pathways, but mediates various biological effects related to inflammation and oxidative stress. We investigated the effects of four new PPAR ligands containing a fibrate scaffold-the PPAR agonists (1a (αEC50 1.0 μM) and 1b (γEC50 0.012 μM)) and antagonists (2a (αIC50 6.5 μM) and 2b (αIC50 0.98 μM, with a weak antagonist activity on γ isoform))-on proinflammatory and oxidative stress biomarkers. The PPAR ligands 1a-b and 2a-b (0.1-10 μM) were tested on isolated liver specimens treated with lipopolysaccharide (LPS), and the levels of lactate dehydrogenase (LDH), prostaglandin (PG) E2, and 8-iso-PGF2α were measured. The effects of these compounds on the gene expression of the adipose tissue markers of browning, PPARα, and PPARγ, in white adipocytes, were evaluated as well. We found a significant reduction in LPS-induced LDH, PGE2, and 8-iso-PGF2α levels after 1a treatment. On the other hand, 1b decreased LPS-induced LDH activity. Compared to the control, 1a stimulated uncoupling protein 1 (UCP1), PR-(PRD1-BF1-RIZ1 homologous) domain containing 16 (PRDM16), deiodinase type II (DIO2), and PPARα and PPARγ gene expression, in 3T3-L1 cells. Similarly, 1b increased UCP1, DIO2, and PPARγ gene expression. 2a-b caused a reduction in the gene expression of UCP1, PRDM16, and DIO2 when tested at 10 μM. In addition, 2a-b significantly decreased PPARα gene expression. A significant reduction in PPARγ gene expression was also found after 2b treatment. The novel PPARα agonist 1a might be a promising lead compound and represents a valuable pharmacological tool for further assessment. The PPARγ agonist 1b could play a minor role in the regulation of inflammatory pathways.

Dysregulation of Th17 cell differentiation and pathogenicity contributes to multiple autoimmune and inflammatory diseases. Previously growth hormone releasing hormone receptor (GHRH-R) deficient mice have been reported to be less susceptible to the induction of experimental autoimmune encephalomyelitis. Here, we show GHRH-R is an important regulator of Th17 cell differentiation in Th17 cell-mediated ocular and neural inflammation. We find that GHRH-R is not expressed in naïve CD4+ T cells, while its expression is induced throughout Th17 cell differentiation in vitro. Mechanistically, GHRH-R activates the JAK-STAT3 pathway, increases the phosphorylation of STAT3, enhances both non-pathogenic and pathogenic Th17 cell differentiation and promotes the gene expression signatures of pathogenic Th17 cells. Enhancing this signaling by GHRH agonist promotes, while inhibiting this signaling by GHRH antagonist or GHRH-R deficiency reduces, Th17 cell differentiation in vitro and Th17 cell-mediated ocular and neural inflammation in vivo. Thus, GHRH-R signaling functions as a critical factor that regulates Th17 cell differentiation and Th17 cell-mediated autoimmune ocular and neural inflammation.

Pancreatic carcinoma is one of the cancers with the worse prognosis, thus any therapeutic improvement is imperative. Cytotoxic LH-RH analog, AN-152 (proprietary designation, AEZS-108), consisting of doxorubicin (DOX) conjugated to D-Lys⁶LH-RH, is now in clinical trials for targeted therapy of several sex hormone-dependent tumors that express LH-RH receptors. We investigated LH-RH receptors in human pancreatic carcinoma and the effects of AN-152 (AEZS-108) on experimental pancreatic cancers. We determined LH-RH receptor presence in human pancreatic cancer samples by immunohistochemistry and, in three human pancreatic cancer lines (SW-1990, Panc-1 and CFPAC-1), by binding assays and Western blotting. The effects of the cytotoxic LH-RH analog were investigated on growth of these same cancer lines xenografted into nude mice. We also analyzed differences between the antitumor effects of the cytotoxic analog and its cytotoxic radical alone, doxorubicin (DOX), on the expression of cancer-related genes by PCR arrays. LH-RH receptors were expressed in two randomly selected surgically removed human pancreatic cancer samples and in all three cancer lines. Cytotoxic LH-RH analogs powerfully inhibited growth of all three tumor lines in nude mice; AN-152 was significantly stronger than DOX on Panc-1 and CFPAC-1 cancers. PCR array showed that cytotoxic LH-RH analog AN-152 affected the expression of genes associated with cellular migration, invasion, metastasis and angiogenesis more favorably than DOX, however the changes in gene expression varied considerably among the three cancer lines. Cytotoxic LH-RH analog, AEZS-108, may be a useful agent for the treatment of LH-RH receptor positive advanced pancreatic carcinoma.

Current pharmacotherapy for persistent pain related to neuropathy or articular diseases is unsatisfactory, due to the large number of unresponsive patients and side effects. Isothiocyanates (ITCs) are a class of natural or synthetic compounds characterized by the general formula R-NCS. ITCs show antihyperalgesic effects in models of central and peripheral nervous tissue injury and anti-inflammatory properties. The pharmacodynamics are strictly related to the release of the gasotransmitter hydrogen sulfide (H2S) from their moiety. In particular, phenyl ITC (PITC) and 3-carboxyphenyl ITC (3C-PITC) exhibit interesting slow H2S-release properties suitable for treating painful pathology. The aim of the present work was to evaluate the efficacy of PITC and 3C-PITC against mechanical hyperalgesia and spontaneous pain induced by nerve injury and osteoarthritis.

Hydrogen sulfide (H2 S)-releasing agents are viewed as potential antihypertensive drugs. Recently, natural isothiocyanates emerged as original H2 S-donor agents. Among them, erucin, present in some edible cruciferous plants, shows suitable H2 S-releasing properties and features of "druggability." The aim of this work was to investigate the erucin-mediated release of H2 S inside vascular cells, its vasorelaxing effects, and activity on BP of normo and hypertensive animals.

Pheochromocytomas and extra-adrenal paragangliomas (PHEO/PGLs) are rare catecholamine-producing chromaffin cell tumors. For metastatic disease, no effective therapy is available. Overexpression of somatostatin type 2 receptors (SSTR2) in PHEO/PGLs promotes interest in applying therapies using somatostatin analogs linked to radionuclides and/or cytotoxic compounds, such as [(177)Lu]Lu-DOTA-(Tyr(3))octreotate (DOTATATE) and AN-238. Systematic evaluation of such therapies for the treatment of PHEO/PGLs requires sophisticated animal models. In this study, the mouse pheochromocytoma (MPC)-mCherry allograft model showed high tumor densities of murine SSTR2 (mSSTR2) and high tumor uptake of [(64)Cu]Cu-DOTATATE. Using tumor sections, we assessed mSSTR2-specific binding of DOTATATE, AN-238, and somatostatin-14. Therapeutic studies showed substantial reduction of tumor growth and tumor-related renal monoamine excretion in tumor-bearing mice after treatment with [(177)Lu]Lu-DOTATATE compared to AN-238 and doxorubicin. Analyses did not show agonist-dependent receptor downregulation after single mSSTR2-targeting therapies. This study demonstrates that the MPC-mCherry model is a uniquely powerful tool for the preclinical evaluation of SSTR2-targeting theranostic applications in vivo. Our findings highlight the therapeutic potential of somatostatin analogs, especially of [(177)Lu]Lu-DOTATATE, for the treatment of metastatic PHEO/PGLs. Repeated treatment cycles, fractionated combinations of SSTR2-targeting radionuclide and cytotoxic therapies, and other adjuvant compounds addressing additional mechanisms may further enhance therapeutic outcome.

This study evaluated the effects of a modern antagonistic analog of GHRH on tumor growth and on expression of inflammatory cytokine genes in two models of human triple negative breast cancers (TNBC). The TNBC subtype is refractory to the treatment options available for other hormone-independent breast cancers. Inflammatory cytokines play a major role in the cellular signaling associated with breast cancer pathogenesis and enhance epithelial-mesenchymal transitions (EMT), drug resistance, and metastatic potential. Growth hormone-releasing hormone (GHRH) is a hypothalamic neuropeptide which regulates the synthesis and release of growth hormone by the pituitary and is an autocrine/paracrine growth factor for multiple human cancers. The effects of analogs of GHRH on tumoral cytokine expression have not been previously investigated. Animals bearing xenografts of the human TNBC cell lines, HCC1806 and MX-1, were treated with MIA-602, an antagonistic analog of GHRH. Treatment with MIA-602 significantly reduced tumor growth. We quantified transcript levels of the genes for several inflammatory cytokines. Expression of INFγ, IL-1α, IL-4, IL-6, IL-8, IL-10, and TNFα, was significantly reduced by treatment with MIA-602. We conclude that treatment of TNBC with GHRH antagonists reduces tumor growth through an action mediated by tumoral GHRH receptors and produces a suppression of inflammatory cytokine signaling. Silencing of GHRH receptors in vitro with siRNA inhibited the expression of GHRH-R genes and inflammatory cytokine genes in HCC1806 and MX-1 cells. Further studies on GHRH antagonists may facilitate the development of new strategies for the treatment of resistant cancers.

Many bladder cancers progress to invasion with poor prognosis; new therapeutic methods are needed. We developed a cytotoxic LH-RH analog, AN-152 (AEZS-108) containing doxorubicin (DOX), for targeted therapy of cancers expressing LHRH receptors. We investigated the expression of LH-RH receptors in clinical bladder cancers and in HT-1376, J82, RT-4 and HT-1197 human bladder cancer lines. The effect of analog, AN-152, on growth of these tumor lines xenografted into nude mice was analyzed. Using molecular and functional assays, we also evaluated the differences between the effects of AN-152, and DOX alone. We demonstrated the expression of LH-RH receptors on 18 clinical bladder cancers by immunohistochemistry and on four human urinary bladder cancer lines HT-1376, J82, RT-4 and HT-1197 by Western blotting and binding assays. AN-152 powerfully inhibited growth of these bladder cancers in nude mice. AN-152 exerted greater effects than DOX and was less toxic. DOX activated strong multidrug resistance mechanisms in RT-4 and HT-1197 cancers, while AN-152 had no or less such effect. PCR assays and in vitro studies revealed differences in the action of AN-152 and DOX on the expression of genes involved in apoptosis. These results suggest that targeted cytotoxic LH-RH analog, AN-152 (AEZS- 108), should be examined for treatment of patients with LH-RH receptor positive invasive bladder cancers.

The extrahypothalamic growth hormone-releasing hormone (GHRH) and its cognate receptors (GHRH-Rs) and splice variants are expressed in a variety of cancers. It has been shown that the pituitary type of GHRH-R (pGHRH-R) mediates the inhibition of tumor growth induced by GHRH-R antagonists. However, GHRH-R antagonists can also suppress some cancers that do not express pGHRH-R, yet the underlying mechanisms have not been determined. Here, using human esophageal squamous cell carcinoma (ESCC) as a model, we were able to reveal that SV1, a known splice variant of GHRH-R, is responsible for the inhibition induced by GHRH-R antagonist MIA-602. We demonstrated that GHRH-R splice variant 1 (SV1) is a hypoxia-driven promoter of tumor progression. Hypoxia-elevated SV1 activates a key glycolytic enzyme, muscle-type phosphofructokinase (PFKM), through the nuclear factor kappa B (NF-κB) pathway, which enhances glycolytic metabolism and promotes progression of ESCC. The malignant actions induced by the SV1-NF-κB-PFKM pathway could be reversed by MIA-602. Altogether, our studies demonstrate a mechanism by which GHRH-R antagonists target SV1. Our findings suggest that SV1 is a hypoxia-induced oncogenic promoter which can be an alternative target of GHRH-R antagonists.

PPARγ agonists are implicated in the regulation of diabetes and metabolic syndrome and have therapeutic potential in brain disorders. PPARγ modulates appetite through its central effects, especially on the hypothalamic arcuate nucleus (ARC). Previous studies demonstrated that the small molecule GL516 is a PPARγ agonist able to reduce oxidative stress and apoptosis with a potential neuroprotective role. Herein, we investigated the effects of GL516, in vitro and ex vivo, on the levels of hypothalamic dopamine (DA) and serotonin (5-HT). The gene expressions of neuropeptide Y, CART, AgRP, and POMC, which play master roles in the neuroendocrine regulation of feeding behavior and energy balance, were also evaluated. HypoE22 cells were treated with H2O2 (300 μM) for 2 h e 30' and with different concentrations of GL516 (1 nM-100 µM). The cell viability was evaluated after 24 and 48 h of culturing using the MTT test. DA and 5-HT levels in the HypoE22 cell supernatants were analyzed through HPLC; an ex vivo study on isolated hypothalamic specimens challenged with scalar concentrations of GL516 (1-100 µM) and with pioglitazone (10 µM) was carried out. The gene expressions of CART, NPY, AgRP, and POMC were also determined by a quantitative real-time PCR. The results obtained showed that GL516 was able to reduce DA and 5-HT turnover; moreover, it was effective in stimulating NPY and AgRP gene expressions with a concomitant reduction in CART and POMC gene expressions. These results highlight the capability of GL516 to modulate neuropeptide pathways deeply involved in appetite control suggesting an orexigenic effect. These findings emphasize the potential use of GL516 as a promising candidate for therapeutical applications in neurodegenerative diseases associated with the reduction in food intake and stimulation of catabolic pathways.

More than 25% of patients diagnosed with endometrial carcinoma have invasive primary cancer accompanied by metastases. Growth hormone-releasing hormone (GHRH) plays an important role in reproduction. Here, we examined the effect of a GHRH antagonist on the motility of endometrial cancer cells and the mechanisms of action of the antagonist in endometrial cancer. Western blotting and immunohistochemistry (IHC) were used to determine the expression of the GHRH receptor protein. The activity of Twist and N-cadherin was determined by Western blotting. Cell motility was assessed by an invasion and migration assay. GHRH receptor siRNA was applied to knockdown the GHRH receptor in endometrial cancer cells. The GHRH antagonist inhibited cell motility in a dose-dependent manner. The GHRH antagonist inhibited cell motility and suppressed the expression of Twist and N-cadherin, and the suppression was abolished by GHRH receptor siRNA pretreatment. Moreover, the inhibition of Twist and N-cadherin with Twist siRNA and N-cadherin siRNA, respectively, suppressed cell motility. Our study indicates that the GHRH antagonist inhibited the cell motility of endometrial cancer cells through the GHRH receptor via the suppression of Twist and N-cadherin. Our findings represent a new concept in the mechanism of GHRH antagonist-suppressed cell motility in endometrial cancer cells and suggest the possibility of exploring GHRH antagonists as potential therapeutics for the treatment of human endometrial cancer.

Industrial hemp is a multiuse crop whose phytocomplex includes terpenophenolics and flavonoids. In the present study, the phenolic and terpenophenolic compounds were assayed in the water extract of the hemp variety Futura 75. Protective effects were also investigated in human fibroblast and keratinocytes and isolate mouse skin specimens, which were exposed to hydrogen peroxide and/or to the extract (1-500 µg/mL). The results of phytochemical analysis suggested the cannabidiol, cannabidiolic acid and rutin as the prominent phytocompounds. In the in vitro system represented by human keratinocytes and fibroblasts, the hemp extract was found to be able to protect cells from cytotoxicity and apoptosis induced by oxidative stress. Moreover, modulatory effects on IL-6, a key mediator in skin proliferation, were found. In isolated rat skin, the extract reduced hydrogen peroxide-induced l-dopa turnover, prostaglandin-E2 production and the ratio kynurenine/tryptpophan, thus corroborating anti-inflammatory/antioxidant effects. The in silico docking studies also highlighted the putative interactions between cannabidiol, cannabidiolic acid and rutin with tyrosinase and indoleamine-2,3-dioxygenase, involved in l-dopa turnover and tryptophan conversion in kynurenine, respectively. In conclusion, the present findings showed the efficacy of hemp water extract as a skin protective agent. This could be partly related to the extract content in cannabidiol, cannabidiolic acid and rutin.

Cydonia oblonga Mill., normally known as the quince fruit, has been widely used in agro-food industries mainly to produce jams and jellies. However, other parts of the plants are still underutilized and not completely assessed for their nutraceutical profile. Therefore, in this work, the polyphenolic profile of C. oblonga was investigated using an untargeted metabolomics approach based on high-resolution mass spectrometry. Several compounds were identified in the different parts of the plants, including flavonoids (i.e., anthocyanins, flavones, flavan-3-ols, and flavonols), phenolic acids (both hydroxycinnamics and hydroxybenzoics), low-molecular-weight phenolics (tyrosol equivalents), lignans, and stilbenes. Overall, C. oblonga leaves showed the highest in vitro antioxidant potential, as revealed by 2,2-difenil-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) assays, being 189.5, 285.6, 158.9, and 348.8 mg Trolox Equivalent/g, respectively. The enzymes acetyl- and butyryl-cholinesterases were both inhibited by the different plant parts of C. oblonga, with stems showing the higher inhibitory potential. Interestingly, the fruit extracts were the only parts inhibiting the α-glucosidase, with a value of 1.36 mmol acarbose equivalents (ACAE)/g. On the other hand, strong tyrosinase inhibition was found for stems and leaves, being 72.11 and 68.32 mg Kojic acid Equivalent/g, respectively. Finally, a high number of significant (0.05 < p < 0.01) correlations were outlined between phenolics (mainly anthocyanins, flava-3-ols, and tyrosol equivalents) and the different biological assays. Taken together, our findings suggest a potential exploitation of C. oblonga leaves and stems for the food, pharmaceutical, and cosmetic industries.

Pituitary adenomas (PAs) are intracranial tumors, often associated with excessive hormonal secretion and severe comorbidities. Some patients are resistant to medical therapies; therefore, novel treatment options are needed. Antagonists of growth hormone-releasing hormone (GHRH) exert potent anticancer effects, and early GHRH antagonists were found to inhibit GHRH-induced secretion of pituitary GH in vitro and in vivo. However, the antitumor role of GHRH antagonists in PAs is largely unknown. Here, we show that the GHRH antagonists of MIAMI class, MIA-602 and MIA-690, inhibited cell viability and growth and promoted apoptosis in GH/prolactin-secreting GH3 PA cells transfected with human GHRH receptor (GH3-GHRHR), and in adrenocorticotropic hormone ACTH-secreting AtT20 PA cells. GHRH antagonists also reduced the expression of proteins involved in tumorigenesis and cancer progression, upregulated proapoptotic molecules, and lowered GHRH receptor levels. The combination of MIA-690 with temozolomide synergistically blunted the viability of GH3-GHRHR and AtT20 cells. Moreover, MIA-690 reduced both basal and GHRH-induced secretion of GH and intracellular cAMP levels. Finally, GHRH antagonists inhibited cell viability in human primary GH- and ACTH-PA cell cultures. Overall, our results suggest that GHRH antagonists, either alone or in combination with pharmacological treatments, may be considered for further development as therapy for PAs.