Relaxin and Matrix Metalloproteinase-9 in Angiotensin II-Induced Abdominal Aortic Aneurysms.

BACKGROUND: This study determined whether relaxin or matrix metalloproteinase (MMP)-9 influences angiotensin II (AngII)-induced abdominal aortic aneurysms (AAA).Methods and Results:Male C57BL/6 or apolipoprotein E-/-mice were infused with AngII with or without relaxin. Relaxin did not influence AngII-induced AAA in either mouse strain. Infusion of AngII reduced, but relaxin increased, MMP-9 mRNA in macrophages. We then determined the effects of MMP-9 deficiency on AAA in apolipoprotein E-/-mice. MMP-9 deficiency led to AAA formation in the absence of AngII, and augmented AngII-induced aortic rupture and AAA incidence. CONCLUSIONS: MMP-9 deficiency augmented AngII-induced AAA.

Oncolytic adenovirus expressing relaxin (YDC002) enhances therapeutic efficacy of gemcitabine against pancreatic cancer.

Pancreatic cancer is a highly lethal disease for which limited therapeutic options are available. Pancreatic cancer exhibits a pronounced collagen-rich stromal reaction, which induces chemoresistance by inhibiting drug diffusion into the tumor. Complementary treatment with oncolytic virus such as an oncolytic adenovirus expressing relaxin (YDC002) is an innovative treatment option for combating chemoresistant pancreatic cancer. Here, we examined the ability of combined treatment with gemcitabine and YDC002, which degrades extracellular matrix (ECM), to efficiently treat chemoresistant and desmoplastic pancreatic cancer. Gemcitabine alone exhibited similarly low cytotoxicity toward pancreatic cancer cells throughout the concentration range (1-50 µM) used, whereas the combination of YDC002 and a subtherapeutic dose of gemcitabine (0.01-0.05 µM) resulted in potent anticancer effects through effective induction of apoptosis. Importantly, YDC002 combined with gemcitabine significantly attenuated the expression of major ECM components including collagens, fibronectin, and elastin in tumor spheroids and xenograft tumors compared with gemcitabine alone, resulting in potent induction of apoptosis, gemcitabine-mediated cytotoxicity, and an oncolytic effect through degradation of tumor ECM. Our results demonstrate that YDC002 can selectively degrade aberrant ECM and attenuate the ECM-induced chemoresistance observed in desmoplastic pancreatic tumor, resulting in a potent antitumor effect through effective induction of apoptosis.

Relaxin-2 expression in oral squamous cell carcinoma.

BACKGROUND: When advanced, oral squamous cell carcinoma (OSCC) may involve adjacent non-epithelial structures, and the prognosis is worse for bone invasion. Human relaxin-2 is a peptide hormone that has recently been associated with cancer. It can induce human osteoclast differentiation and activation, suggesting a role in tumor-driven osteolysis. This study was a preliminary assessment of the prognostic role of relaxin-2 in surgical specimens of OSCC tissue and adjacent but uninvolved mandibular/maxillary bone. METHODS: Relaxin-2 immunohistochemical expression and reaction intensity were assessed in tumor and uninvolved adjacent mandibular/maxillary bone specimens from 23 operated OSCC patients. RESULTS: All OSCC specimens were positive for relaxin-2. The intensity of its reaction in OSCC correlated significantly with the pattern of the tumor's invasion front (p = 0.02), being higher with the infiltrative pattern. Mean relaxin-2 immunohistochemical expression was higher in patients whose OSCC recurred after treatment than those experiencing no recurrence (81.3% ± 22.6% vs. 59.5% ± 29.7%, respectively). A significant direct association emerged between relaxin-2 expression in OSCC specimens and recurrence rate (p = 0.049). CONCLUSIONS: Relaxin-2 expression in OSCC should be further investigated as a potentially useful marker for identifying patients at higher risk of recurrence, who might benefit from closer follow-up and more aggressive adjuvant therapy. In other oncological settings, increasing evidence of relaxin being produced by cancer cells is prompting efforts to synthesize human relaxin-2 analogs capable of acting as antagonists and limiting tumor growth.

Secretory overexpression and isotopic labeling of the chimeric relaxin family peptide R3/I5 in Pichia pastoris.

Relaxin family peptides are a group of peptide hormones with divergent biological functions. Mature relaxin family peptides are typically composed of two polypeptide chains with three disulfide linkages, rendering their preparation a challenging task. In the present study, we established an efficient approach for preparation of the chimeric relaxin family peptide R3/I5 through secretory overexpression in Pichia pastoris and in vitro enzymatic maturation. A designed single-chain R3/I5 precursor containing the B-chain of human relaxin-3 and the A-chain of human INSL5 was overexpressed in PichiaPink strain 1 by high-density fermentation in a two-liter fermenter, and approximately 200 mg of purified precursor was obtained from one liter of the fermentation supernatant. We also developed an economical approach for preparation of the uniformly (15)N-labeled R3/I5 precursor by culturing in shaking flasks, and approximately 15 mg of purified (15)N-labeled precursor was obtained from one liter of the culture supernatant. After purification by cation ion-exchange chromatography and reverse-phase high performance liquid chromatography, the R3/I5 precursor was converted to the mature two-chain form by sequential treatment with endoproteinase Lys-C and carboxypeptidase B. The mature R3/I5 peptide had an α-helix-dominated conformation and retained full receptor-binding and receptor activation activities. Thus, Pichia overexpression was an efficient approach for sample preparation and isotopic labeling of the chimeric R3/I5 peptide. This approach could also be extended to the preparation of other relaxin family peptides in future studies.

Prognostic significance of relaxin-2 and S100A4 expression in osteosarcoma.

OBJECTIVE: Relaxin-2 (RLN2) and calcium-binding protein S100A4 was overexpressed in many cancers. Experimental evidence indicated enhanced tumor cell invasion by RLN2 involves the upregulation of S100A4. However, the relationship between them in cancers is not clear. In the present study, we investigate the expression of relaxin-2 protein and calcium-binding protein S100A4 in osteosarcoma by immunohistochemistry assay and their relationship to the clinicopathological parameters and prognosis of osteosarcoma (OS). MATERIALS AND METHODS: Expression status of RLN2 and S100A4 was examined in 130 surgical specimens of primary OS by immunohistochemistry. Correlation between the expression of RLN2 and S100A4 and clinicopathological parameters was analyzed. RESULTS: 78 of 130 (60%) specimens of primary OS were positive for RLN2. 67 of 130 (51.5%) specimens showed positive expression of S100A4. The positive correlation between RLN2 and S100A4 expression was significant in cancer tissues (p = 0.02). RLN2 and S100A4 expression in osteosarcoma tissues was significantly higher than that in corresponding noncancerous bone tissues both p = 0.000). In addition, high RLN2 and S100A4 expression more frequently occurred in osteosarcoma tissues with advanced clinical stage (both p < 0.05) and positive distant metastasis (both p < 0.05). Moreover, osteosarcoma patients with high RLN2 and S100A4 expression had significantly shorter overall survival and disease-free survival (both p < 0.001) when compared with patients with the low expression of RLN2 and S100A4. On Cox multivariate analysis, RLN2 and S100A4 overexpression, distant metastasis were the independent and significant prognostic factor to predict poor overall survival and disease-free survival. CONCLUSIONS: We, therefore, suggested overexpression of RLN2 and S100A4 might be related to the prediction of metastasis potency and poor prognosis for osteosarcoma patients. Detection of RLN2 and S100A4 might be useful in evaluating the outcome of patients with OS.

Effect of zeranol on expression of apoptotic and cell cycle proteins in murine placentae.

Mycotoxins are chemicals produced by fungus and many of them are toxic to humans. Zeranol is a mycotoxin used to promote growth in cattle in North America; yet such a practice draws concern about the residual compound in meat in European countries. In the present study, the toxicity of zeranol was tested in a mouse model for reproduction. Pregnant ICR mice were given p.o. daily doses of zeranol at 0, 1, 10, 100mg/kg for 4 days (from E13.5 to E16.5). Increased rates of fetal resorption at late gestation (E17.5) and preterm birth (

Relaxin 2 is functional at the ocular surface and promotes corneal wound healing.

PURPOSE: We aimed to determine if the insulin-like peptide hormone relaxin 2 (RLN2) is expressed at the ocular surface and in tears and if RLN2 influences wound healing at the ocular surface, which is associated with extracellular matrix (ECM) remodeling. METHODS: We analyzed transcript levels of human RLN2 and its cognate relaxin-like receptors RXFP1 and RXFP2 in tissues of the ocular surface, lacrimal apparatus, and human corneal (HCE), conjunctival (HCjE) and sebaceous (SC) cell lines. We analyzed effects of human RLN2 on cell proliferation and migration and quantified mRNA expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in HCE, HCjE, and SC. Using an alkali-induced corneal wounding model, we analyzed the wound healing rate in C57BL/6 mice eyes after topically applied RLN2. RESULTS: The presence of RLN2, RXFP1, and RXFP2 transcripts was detected in lacrimal gland, eyelid, conjunctiva, cornea, primary corneal fibroblasts, nasolacrimal ducts, and all three cell lines. ELISA revealed RLN2 protein in all ocular surface tissues analyzed and in human tears. Stimulation of HCE, HCjE, and SC with RLN2 significantly increased cell proliferation and migration. Relative mRNA expression levels of MMP2, MMP9, TIMP1, and TIMP2 were significantly influenced by RLN2 in all three cell lines at different time points studied. The local application of RLN2 onto denuded corneal surface resulted in significantly elevated corneal wound healing. CONCLUSIONS: Our data support a novel role for the RLN2 ligand-receptor system at the ocular surface and in the lacrimal apparatus as a potential future therapeutic during wound healing at the ocular surface.

Cellular retrograde cardiomyoplasty and relaxin therapy for postischemic myocardial repair in a rat model.

We sought to determine whether skeletal myoblasts, wild-type or engineered to express relaxin, might improve myocardial viability and performance in a rat model of chronic myocardial infarction. Our purpose was to investigate a potential new therapy for heart failure. From October 2005 through September 2009, we surgically induced acute myocardial infarction in 80 male Wistar rats. Thirty days after surgery, the rats underwent reoperation for the retrograde coronary venous infusion of skeletal myoblasts, relaxin, or both. The animals were randomly assigned to 4 experimental groups: R1 (the control group, which underwent saline-solution infusion), R2 (systemic relaxin therapy), R3 (myoblast infusion), and R4 (myoblast infusion and systemic relaxin therapy). Echocardiography, positron emission tomography, and cellular and histologic analysis were performed at 4 established time points. Mortality rates were similar among the groups. Postinfarction echocardiographic evaluation revealed similar left ventricular dysfunction. Viable myocardium, evaluated with positron emission tomography, was analogous. After therapy, the echocardiographic values of cardiac function improved significantly (P<0.05) in all groups except R1. Myocardial viability volume increased significantly in groups R3 and R4 (P<0.05) but was unchanged in groups R2 and R1. In group R4, the echocardiographic and positron emission tomographic results improved significantly (P<0.001). Histologic analysis showed that myoblasts settled in regions of ischemic scarring, especially when combined with relaxin. The retrograde venous route is safe, effective, and clinically feasible for cell delivery. Myoblasts and relaxin are better than either alone in terms of myocardial viability and performance improvement.

A novel role for relaxin-2 in the pathogenesis of primary varicosis.

BACKGROUND: Varicose veins affect up to 40% of men and up to 51% of women. The pathophysiology of primary varicosis is poorly understood. Theories ranging from incompetence of the venous valves to structural changes in the vein wall have been proposed. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the functional state of the intramural smooth muscle cells (n = 14 pairs matched for age and gender) and the expression of relaxin-2 and its receptors RXFP1 and RXFP2 in samples of varicose and healthy great saphenous veins (GSV) (n = 21 healthy GSV; n = 46 varicose GSV). Relaxin-2 and RXFP1 contents were determined in tissue samples (n = 9 samples per group). Pharmacological analyses were performed in a perfusion chamber. Morphometric determination of the nuclear size of the smooth muscle compartment yielded no significant difference in varicose GSV in comparison with the healthy controls. Relaxin-2 and its receptors were expressed in the muscular layer, endothelial cells and in blood vessels contained in the vein wall. Immunohistochemical expression of relaxin-2, RXFP1 and RXFP2 was significantly decreased in varicose GSV. Relaxin-2 and RXFP1 measured by ELISA and Western Blot were decreased in varicose GSV (relaxin-2 ELISA healthy vs. varicose GSV: 12.49±0.66 pg/mg versus 9.12±3.39 pg/mg of total protein; p = 0.01; Student's T-test). Contractions of vein samples induced by cholinergic or adrenergic stimulation were antagonized by relaxin-2. CONCLUSIONS/SIGNIFICANCE: We report that relaxin-2 and its receptors RXFP1 and RXFP2 are expressed in GSV and that their expression is significantly decreased in varicose GSV. Further, we were able to demonstrate a functional pharmacological relaxin-2 system in varicose GSV. Our results suggest a novel role for relaxin-2 in the pathogenesis of primary varicosis, rendering relaxin-2 a novel possible pharmacological agent for the treatment of this widely prevailing venous disease.

Relaxin-3 systems in the brain--the first 10 years.

The relaxin-3 gene was identified in 2001 by searching the human genome database for homologues of the relaxin hormone, and was subsequently discovered to encode a highly conserved neuropeptide in mammals and lower species. In the decade since its discovery there have been significant advances in our knowledge of the peptide, including the identification of its cognate receptor (a type 1 G-protein coupled receptor, GPCR135 or RXFP3), an understanding of its structure-activity and associated cellular signalling, and the elucidation of key neuroanatomical aspects of relaxin-3/RXFP3 networks in mammalian brain. The latter studies revealed that relaxin-3 is expressed within GABA neurons of the brainstem including an area known as the nucleus incertus, and that ascending relaxin-3 projections innervate a broad range of RXFP3-rich forebrain areas. These maps provided a foundation for pharmacological and physiological studies to elucidate the neurobiological nature of relaxin-3/RXFP3 signalling in vivo. Recent findings from our laboratory and others suggest the relaxin-3 neural network represents a newly identified ascending arousal system, able to modulate a range of interrelated functions including responses to stress, spatial and emotional memory, feeding and metabolism, motivation and reward, and circadian rhythm and sleep/wake states. More research is now required to discover further important facts about relaxin-3 neurons, such as their various regulatory inputs, and to characterise populations of RXFP3-positive neurons and determine their influence on particular neural circuits, physiology and complex behaviour.

Examination of relaxin and its receptors expression in pig gametes and embryos.

BACKGROUND: Relaxin is a small peptide also known as pregnancy hormone in many mammals. It is synthesized by both male and female tissues, and its secretions are found in various body fluids such as plasma serum, ovarian follicular fluid, utero-oviduct secretions, and seminal plasma of many mammals, including pigs. However, the presence and effects of relaxin in porcine gametes and embryos are still not well-known. The purpose of this study was to assess the presence of relaxin and its receptors RXFP1 and RXFP2 in pig gametes and embryos. METHODS: Immature cumulus-oocyte complexes (COCs) were aspirated from sows' ovaries collected at the abattoir. After in vitro-maturation, COCs were in vitro-fertilized and cultured. For studies, immature and mature COCs were separately collected, and oocytes were freed from their surrounding cumulus cells. Denuded oocytes, cumulus cells, mature boar spermatozoa, zygotes, and embryos (cleaved and blastocysts) were harvested for temporal and spatial gene expression studies. Sections of ovary, granulosa and neonatal porcine uterine cells were also collected to use as controls. RESULTS: Using both semi-quantitative and quantitative PCRs, relaxin transcripts were not detected in all tested samples, while RXFP1 and RXFP2 mRNA were present. Both receptor gene products were found at higher levels in oocytes compared to cumulus cells, irrespective of the maturation time. Cleaved-embryos contained higher levels of RXFP2 mRNA, whereas, blastocysts were characterized by a higher RXFP1 mRNA content. Using western-immunoblotting or in situ immunofluorescence, relaxin and its receptor proteins were detected in all samples. Their fluorescence intensities were consistently more important in mature oocytes than immature ones. The RXFP1 and RXFP2 signal intensities were mostly located in the plasma membrane region, while the relaxin ones appeared homogeneously distributed within the oocytes and embryonic cells. Furthermore, spermatozoa displayed stronger RXFP2 signal than RXFP1 after western-immunoblotting. CONCLUSION: All together, our findings suggest potential roles of relaxin and its receptors during oocyte maturation, early embryo development, and beyond.

Relaxin family peptides in the male reproductive system--a critical appraisal.

The human genome project has identified, besides ovarian relaxin (RLN), six other relaxin-like molecules (RLN3, H1-RLN, INSL3-6), most of which appear to be expressed in the testis and/or male reproductive system, together with four different G-protein-coupled receptors responsive to one or other of these peptides. Earlier work on relaxin in the male assumed the simplistic hypothesis of only a single relaxin-like entity. This review systematically examines the expression and physiology of relaxin-like molecules in the male reproductive system in order to reappraise the importance of this hormone system for male reproductive function. Although there are important species differences, only INSL3 and INSL6 appear to be generally expressed at a moderately high level within the testis, whereas ovarian RLN is consistently a major secretory product of the prostate epithelium. However, all members of this relaxin-like family appear to be expressed also at a low level in different organs of the male reproductive system, suggesting possible autocrine/paracrine effects. The four receptors (RXFP1-4) for these peptides are also expressed to differing levels in both somatic and seminiferous compartments of the testis and in the prostate, supporting relevant functions for most members of this interesting peptide family. Recent studies of relaxin family peptides in prostate pathology highlight their functional importance in the clinical context as potential causative, diagnostic and therapeutic agents and warrant more specific and detailed studies of their roles also in regard to male fertility and other aspects of male reproductive function.

Expression of insulin-like 3 (INSL3) and differential splicing of its receptor in the ovary of rhesus macaques.

BACKGROUND: Although insulin-like 3 (INSL3) has been identified in the gonad of both sexes in many species, there are only limited reports on the distribution of INSL3 and its receptor, relaxin/insulin-like family peptide receptor 2 (RXFP2), in the primate ovary. Since the hormone-receptor pair is believed to play a role in female reproduction, investigating the transcription of INSL3/RXFP2 genes and the spatiotemporal expression of INSL3 in the nonhuman primate may shed light on the functional aspects of the system in humans. METHODS: Database mining, molecular and immunological methods were applied. RESULTS: One single INSL3 transcript and three novel splice variant transcripts of RXFP2 were identified in the ovary of rhesus macaques. While the full-length RXFP2 transcript is barely detectable in granulosa cells during the periovulatory period, INSL3 transcript and protein are highly abundant in theca cells surrounding antral follicles. Moreover, the INSL3 level in follicular fluid is 3-4 times higher than that in female serum which remains low throughout the menstrual cycle. CONCLUSIONS: The presence of INSL3 and its receptor in the ovary implies a potential role of the ligand-receptor pair in female reproduction in nonhuman primates. However, the existence of multiple splice variants of RXFP2 indicates a very complex nature of the hormone-receptor system.

A simple approach for the preparation of mature human relaxin-3.

Relaxin-3 (also known as INSL7) is the most recently identified member of the insulin-like family. It is predominantly expressed in the nucleus incertus of the brain and involved in the control of stress response, food intake, and reproduction. In the present work, we have established a simple approach for the preparation of the mature human relaxin-3 peptide. We first designed and recombinantly expressed a single-chain relaxin-3 precursor in E. coli cells. After purification by immobilized metal ion affinity chromatography, refolding in vitro through disulfide reshuffling, and digestion by endoproteinase Asp-N, mature human relaxin-3 was obtained in high yield and at low cost. Peptide mapping and circular dichroism spectroscopy studies suggested that the recombinant relaxin-3 adopted an insulin-like fold with the expected disulfide linkages. The recombinant mature relaxin-3 was fully active in both RXFP3 binding and activation assays. The activity of the single-chain precursor was very low, suggesting that a free C-terminus of the B-chain is necessary for receptor-binding and activation of relaxin-3. Our present work provides a highly efficient approach for the preparation of relaxin-3 as well as its analogues for functional and structural analyses.

Relaxin drives Wnt signaling through upregulation of PCDHY in prostate cancer.

BACKGROUND: Relaxin, a potent peptide hormone of the insulin-like family normally produced and secreted by the human prostate, is upregulated in castrate resistant prostate cancer progression. In various tissues, relaxin increases angiogenesis and cell motility through upregulation of vascular endothelial growth factor, matrix metalloproteases, and nitric oxide, and therefore maybe an attractive target for cancer therapeutics. METHODS: To examine the role of relaxin in prostate cancer progression, LNCaP cells stably transfected with relaxin (LNCaP(RLN)) were used to form xenograft tumors, and microarray expression analysis was subsequently performed to determine novel pathways regulated by relaxin. Prostate cancer tissue microarrays from patient samples were stained by immunohistochemistry for further validation and correlation of the findings. RESULTS: Expression analysis identified novel relaxin regulated pathways, including the ProtocadherinY (PCDHY)/Wnt pathway. PCDHY, which upregulates Wnt11, has previously been shown to stabilize beta-catenin, causing beta-catenin to translocate from the cytoplasmic membrane to the nucleus and initiate TCF-mediated signaling. LNCaP(RLN) xenografts exhibit increased PCDHY expression and increased cytoplasmic localization of beta-catenin, suggesting relaxin directs Wnt11 overexpression through PCDHY upregulation. Similarly, prostate cancer samples from patients who have undergone androgen ablation have increased Wnt11 expression, which is further upregulated in castrate resistant tissues. Like relaxin, Wnt11, and PCDHY are negatively regulated by androgens, and further analysis indicated that the overexpression of relaxin results in dysregulation of androgen-regulated genes. CONCLUSIONS: These data suggest that prostate cancer cell motility and altered androgen receptor activity attributed to relaxin may be mediated in part by Wnt11.

Relaxin and the progression of kidney disease.

PURPOSE OF REVIEW: Relaxin is a peptide hormone named for its ability to soften the birth canal in preparation for parturition. Not surprisingly, therefore, subsequent attention has focused on its role in remodeling connective tissue in other organs, especially in circumstances of pathological fibrosis and scarring. This review discusses the renoprotective and therapeutic potential of relaxin in the kidney, which has highlighted its relevance in human pathophysiology. RECENT FINDINGS: Growing evidence suggests that the kidney is both a therapeutic target and potential source of relaxin. Although the expression of renal relaxin is low, endogenous relaxin appears to play an important role in connective tissue homeostasis within the kidney, whereas exogenous relaxin has been shown to consistently and rapidly abrogate renal fibrosis at many levels, primarily through an ability to interfere with the actions of transforming growth factor beta-1. Furthermore, the vasodilatory and angiogenic properties of relaxin, in addition to its ability to improve renal function in humans, have contributed to its therapeutic significance in renal disease. SUMMARY: Accumulating evidence from studies at the preclinical and clinical level has demonstrated a potential antifibrotic and regenerative capacity of relaxin, directly relevant to the kidney.

Expression and cellular pattern of relaxin mRNA in porcine corpora lutea during pregnancy.

We developed an in situ hybridization method for detecting relaxin mRNA in the porcine corpus luteum (CL) by employing a non-radioactive probe and microwave fixation. We subsequently examined the expression and cellular patterns of relaxin mRNA in the CL during pregnancy and then evaluated whether relaxin mRNA was a factor limiting hormone production by the CL. Digoxigenin (DIG)-labeled RNA probes complementary to porcine relaxin mRNA were produced by in vitro transcription. The specificity was validated by showing, by Northern analysis, that the anti-sense probe hybridized to a 1.0-kb relaxin transcript in the CL. Microwave fixation (2-min irradiation in a conventional microwave oven) combined with DIG-labeled cRNA probes allowed precise and reliable analysis of relaxin mRNA, with superior retention of the mRNA and a higher resolving power. Application of this method to the porcine CL during pregnancy demonstrated that the relaxin mRNA level per cell and the percentage of mRNA-expressing cells increased as gestation progressed, with a marked decline near term. Northern analysis revealed the cellular pattern of relaxin mRNA localization, showing that the increase of relaxin mRNA with advancing pregnancy was attributable to an increase of both the cellular mRNA level and the percentage of mRNA-expressing cells. The present findings, taken together with known relaxin levels in the CL, reveal that changes of relaxin mRNA are correlated with changes of the hormone in the CL during pregnancy, suggesting that the relaxin level is determined by the amount of mRNA available for translation.

Relaxin-expressing, fiber chimeric oncolytic adenovirus prolongs survival of tumor-bearing mice.

Selective replication of oncolytic viruses in tumor cells provides a promising approach for the treatment of human cancers. One of the limitations observed with oncolytic viruses currently used in the treatment of solid tumors is the inefficient spread of virus throughout the tumor mass following intratumoral injection. Data are presented showing that oncolytic adenoviruses expressing the relaxin gene and containing an Ad5/Ad35 chimeric fiber showed significantly enhanced transduction and increased virus spread throughout the tumor when compared with non-relaxin-expressing, Ad5-based viruses. The increased spread of such viruses throughout tumors correlated well with improved antitumor efficacy and overall survival in two highly metastatic tumor models. Furthermore, nonreplicating viruses expressing relaxin did not increase metastases, suggesting that high level expression of relaxin will not enhance metastatic spread of tumors. In summary, the data show that relaxin may play a role in rearranging matrix components within tumors, which helps recombinant oncolytic adenoviruses to spread effectively throughout the tumor mass and thereby increase the extent of viral replication within the tumor. Expressing relaxin from Ad5/Ad35 fiber chimeric adenoviruses may prove a potent and novel approach to treating patients with cancer.

Relaxin becomes upregulated during prostate cancer progression to androgen independence and is negatively regulated by androgens.

BACKGROUND: Relaxin is a potent peptide hormone normally secreted by the prostate. This study characterized relaxin expression during prostate cancer progression to androgen independence (AI), and in response to androgens. METHODS: The prostate cancer cell line, LNCaP, was assayed by microarrays and confirmatory Northern analysis to assess changes in relaxin levels due to androgen treatment and in LNCaP xenografts following castration. Relaxin protein levels were examined by immunohistochemistry (IHC) in tissue microarrays of human prostate cancer samples following androgen ablation. RESULTS: Relaxin levels decreased in a time and concentration-dependent manner due to androgens in vitro, and increased in xenografts post-castration. Relaxin increased in radical prostatectomy specimens after 6 months of androgen ablation and in AI tumors, was highest in bone metastases. CONCLUSIONS: Relaxin is negatively regulated by androgens in vitro and in vivo, which correlates to clinical prostate cancer specimens following androgen ablation. The role of relaxin in angiogenesis and tissue remodeling suggests it may contribute to prostate cancer progression.