Knocking down gene expression for growth hormone-releasing hormone inhibits proliferation of human cancer cell lines

Splice Variant 1 (SV-1) of growth hormone-releasing hormone (GHRH) receptor, found in a wide range of human cancers and established human cancer cell lines, is a functional receptor with ligand-dependent and independent activity. In the present study, we demonstrated by western blots the presence of the SV1 of GHRH receptor and the production of GHRH in MDA-MB-468, MDA-MB-435S and T47D human breast cancer cell lines, LNCaP prostate cancer cell line as well as in NCI H838 non-small cell lung carcinoma. We have also shown that GHRH produced in the conditioned media of these cell lines is biologically active. We then inhibited the intrinsic production of GHRH in these cancer cell lines using si-RNA, specially designed for human GHRH. The knocking down of the GHRH gene expression suppressed the proliferation of T47D, MDA-MB-435S, MDA-MB-468 breast cancer, LNCaP prostate cancer and NCI H838 non-SCLC cell lines in vitro. However, the replacement of the knocked down GHRH expression by exogenous GHRH (1–29)NH2 re-established the proliferation of the silenced cancer cell lines. Furthermore, the proliferation rate of untransfected cancer cell lines could be stimulated by GHRH (1–29)NH2 and inhibited by GHRH antagonists MZ-5-156, MZ-4-71 and JMR-132. These results extend previous findings on the critical function of GHRH in tumorigenesis and support the role of GHRH as a tumour growth factor

Effective treatment of experimental U-87MG human glioblastoma in nude mice with a targeted cytotoxic bombesin analogue, AN-215

Some brain tumours, such as glioblastomas express high levels of receptors for bombesin/gastrin releasing peptide. We investigated whether bombesin/gastrin releasing peptide receptors found in glioblastoma cell lines can be utilised for targeting of a cytotoxic bombesin analogue, AN-215 consisting of a potent derivative of doxorubicin, 2-pyrrolino-doxorubicin (AN-201) linked to a bombesin-like peptide carrier. This study reports the effect of AN-215 on the growth of U-87MG human glioblastomas xenografted into nude mice. High affinity binding of AN-215 to U-87MG tumours was characterised by an IC50 value of 4.0±0.1 nM, as determined by radioreceptor assays. mRNA analyses revealed the presence of mRNA for BN receptor subtypes 1 and 2. Treatment with AN-215 significantly (P<0.05) extended tumour doubling time from 4.54±0.2 days to 8.18±1.8 days and inhibited tumour growth as demonstrated by a 69.6% reduction in final tumour volume (P<0.001) and a 64.6% decrease in tumour weight as compared to controls. Cytotoxic radical AN-201 at the same dose was ineffective. The antitumour effect of AN-215 could be blocked by pretreatment with an excess of a bombesin antagonist, indicating that the action of this cytotoxic analogue is receptor-mediated. Our results suggest that patients with inoperable brain tumours such as malignant gliomas may benefit from targeted chemotherapy based on cytotoxic bombesin analogue AN-215

Expression of progenitor markers is associated with the functionality of a bioartificial adrenal cortex

This work was in part supported by the International Fund Congenital Adrenal Hyperplasia (IFCAH) (to SRB), by the Deutsche Forschungsgemeinschaft (CRC-TRR 127 (to SRB and BL), CRC-TRR 205 (to SRB, BL and CS), IRTG 2251 (to SRB, BL and CS), and CRU 252 (to SRB and BL)), the German Academic Exchange Service (DAAD) (to GRB) and The TransCampus initiative between TU Dresden and King’s College London (to SRB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Urbilaterian origin of paralogous GnRH and corazonin neuropeptide signalling pathways

This work was supported by funding from the China Scholarship Council (awarded to ST), Leverhulme Trust (grant RGP-2013-351, awarded to MRE), BBSRC (grant BB/M001644/1 awarded to MRE; grant BB/M001032/1 awarded to JHS) and a Company of Biologists (Journal of Experimental Biology) Travelling Fellowship awarded to MZ. IB is supported by a postdoctoral fellowship from the Research Foundation–Flanders (FWO)

Antibodies against gonadotropin-releasing hormone (GnRH) and destruction of enteric neurons in 3 patients suffering from gastrointestinal dysfunction

Background: Antibodies against gonadotropin-releasing hormone (GnRH) and gastrointestinal dysmotility have been found after treatment with GnRH analogues. The aim of this study was to examine the presence of such antibodies in patients with dysmotility not subjected to GnRH treatment and study the anti-GnRH antibody effect on enteric neurons viability in vitro. Methods: Plasma and sera from 3 patients suffering from either enteric dysmotility, irritable bowel syndrome (IBS) or gastroparesis were analysed for C-reactive protein (CRP), and for GnRH antibodies and soluble CD40 by ELISA methods. Primary cultures of small intestinal myenteric neurons were prepared from rats. Neuronal survival was determined after the addition of sera either from the patients with dysmotility, from healthy blood donors, antiserum raised against GnRH or the GnRH analogue buserelin. Only for case 1 a full-thickness bowel wall biopsy was available for immunohistochemical analysis. Results: All 3 patients expressed antibodies against GnRH. The antibody titer correlated to the levels of CD40 (r(s) = 1.000, p < 0.01), but not to CRP. Serum from case 3 with highest anti-GnRH antibody titer, and serum concentrations of sCD40 and CRP, when added to cultured rat myenteric neurons caused remarkable cell death. In contrast, serum from cases 1 and 2 having lower anti-GnRH antibody titer and lower sCD40 levels had no significant effect. Importantly, commercial antibodies against GnRH showed no effect on neuron viability whereas buserelin exerted a protective effect. The full-thickness biopsy from the bowel wall of case 1 showed ganglioneuritis and decrease of GnRH and GnRH receptor. Conclusion: Autoantibodies against GnRH can be detected independently on treatment of GnRH analogue. Whether the generation of the antibody is directly linked to neuron degeneration and chronic gastrointestinal symptoms in patients with intestinal dysmotility, remains to be answered

Somatostatin receptor in human hepatocellular carcinomas: Biological, patient and tumor characteristics

Background/Aim: The evidence on the efficacy of somatostatin analogues in the treatment of hepatocellular carcinoma (HCC) in humans is conflicting. A variety of human tumors demonstrate somatostatin receptors. All subtypes bind human somatostatin with high affinity, while somatostatin analogues bind with high affinity to somatostatin receptor subtype 2 (sst2). We investigated the sst2 expression in HCC and examined whether HCCs expressing sst2 are a distinct subgroup. Patients and Methods: Forty-five human HCCs were tested for sst2 expression and biological alterations. The proliferative capacity was determined with Ki67 immunostaining and the DNA ploidy status was measured by fluorescent in situ hybridization with a chromosome 1-specific repetitive DNA probe. Expression of tumor suppressor genes (p16, p53 and Rb1) was measured by immunohistochemistry. Results: sst2 expression was detected in 30 tumors (67%). No correlation existed between sst2 expression and the immunoprofiles of the tumor suppressor genes, aneuploidy, proliferation, age, gender, α-fetoprotein levels, tumor size, tumor grade and underlying liver disease. Conclusion: In 67% of the patients with HCC, sst2 could be detected in the tumor. No clinical, pathological or biological characteristics were specific for sst2-positive tumors. Copyrigh

A standardised study to compare prostate cancer targeting efficacy of five radiolabelled bombesin analogues

Purpose: Prostate-specific antigen (PSA)-based screening for prostate cancer (PC) has dramatically increased early diagnosis. Current imaging techniques are not optimal to stage early PC adequately. A promising alternative to PC imaging is peptide-based scintigraphy using radiolabelled bombesin (BN) analogues that bind to gastrin-releasing peptide receptors (GRPR) being overexpressed in PC. When labelled to appropriate radionuclides BN targeting of GRPRs may also provide applications for peptide radionuclide receptor therapy (PRRT). Assessment studies under identical experimental conditions allowing a reliable comparison of the potential of such analogues are lacking. This study was performed to evaluate and directly compare five promising radiolabelled BN analogues for their targeting efficacy for PC under standardised conditions. Methods: The BN agonists [111In]DOTA-PESIN, [111In]AMBA, [111In]MP2346 and [111In]MP2653 and one antagonist [99mTc]Demobesin-1 were evaluated in GRPR-overexpressing human PC-3 tumou