Variant 1 Research Articles

RESEARCH ON THE SPECIES OF CARABIDS EXISTING IN SUNFLOWER CULTURE, DEPENDING ON THE APPLIED TECHNOLOGY

The observations were made in a sunflower crop in the north-western extremity of Arad County, in the immediate vicinity of the town Adea, using two variants: Variant 1 (V1), where there were no treatments for the chemical control of the pathogenic agents of the pests; Variant 2 (V2), where chemical treatments were made to the seeds and during the vegetation period against pathogens and pests. In the ecological variant, a larger number of specimens and species were collected in each of the 10 collections compared to the conventional variant, where chemical treatments were carried out to combat pathogens and pests. The most frequently collected carabid species were Pterostichus cylindricus, Pseudophonus pubescens, and Pseudophonus griseus, in both variants. In total, 501 carabid specimens belonging to 16 species were collected in the ecological variant, and 243 specimens belonging to a total of 10 species were collected in the conventional variant.

Influence of Mineral Liquid Fertilization on the Plant Growth of Perennials on Sheep’s Wool–Coir–Vegetation Mats

Perennials are usually pre-cultivated on vegetation mats consisting of coconut fiber (coir), which require weather-dependent irrigation and regular fertilization with fast-acting fertilizer to achieve a saleable condition as quickly as possible. In the pre-cultivation of sheep’s wool–coir–vegetation mats, nitrogen (N) is already sufficiently contained in the vegetation mats due to the natural nitrogen content of the sheep’s wool fibers, so that additional liquid fertilization during pre-cultivation can be dispensed with if necessary. In this study, sheep’s wool–coir–vegetation mats of 4.5 kg/m2 were pre-cultivated with 16 perennial plants (8 species) in 2018. Variant 1 (V1) received regular fertilization with mineral liquid fertilizer (total 8.7 g N/m2) during pre-cultivation. Variant 2 (V2) was not fertilized during pre-cultivation. In spring 2019, all pre-cultivated vegetation mats were lifted and laid on an area prepared with topsoil. No additional fertilization was applied after laying. The overall impression, plant height, number of flowering perennials, and plant coverage were examined in the 2018 and 2019 growing seasons, with only minor differences observed between V1 and V2. The number of flowers, biomass, and nitrogen content were determined for the two aster species used. There were differences between V1 and V2 in 2018, but not in 2019. The coverage of perennials of 50%, which is the prerequisite for the saleability of the vegetation mats, was already achieved on both V1 and V2 after 4 months of pre-cultivation. The overall impression of the perennials on both V1 and V2 also did not differ during pre-cultivation nor in the following year. Therefore, liquid fertilization is not necessary during the pre-cultivation of perennials on sheep’s wool–coir–vegetation mats.

Novel RPTPγ and RPTPζ splice variants from mixed neuron-astrocyte hippocampal cultures as well as from the hippocampi of newborn and adult mice.

Receptor protein tyrosine phosphatases γ and ζ (RPTPγ and RPTPζ) are transmembrane signaling proteins with extracellular carbonic anhydrase-like domains that play vital roles in the development and functioning of the central nervous system (CNS) and are implicated in tumor suppression, neurodegeneration, and sensing of extracellular [CO2] and [HCO3 -]. RPTPγ expresses throughout the body, whereas RPTPζ preferentially expresses in the CNS. Here, we investigate differential RPTPγ-RPTPζ expression in three sources derived from a wild-type laboratory strain of C57BL/6 mice: (a) mixed neuron-astrocyte hippocampal (HC) cultures 14 days post isolation from P0-P2 pups; (b) P0-P2 pup hippocampi; and (c) 9- to 12-week-old adult hippocampi. Regarding RPTPγ, we detect the Ptprg variant-1 (V1) transcript, representing canonical exons 1-30. Moreover, we newly validate the hypothetical assembly [XM_006517956] (propose name, Ptprg-V3), which lacks exon 14. Both transcripts are in all three HC sources. Regarding RPTPζ, we confirm the expression of Ptprz1-V1, detecting it in pups and adults but not in cultures, and Ptprz1-V3 through Ptprz1-V7 in all three preparations. We newly validate hypothetical assemblies Ptprz1-X1 (in cultures and pups), Ptprz1-X2 (in all three), and Ptprz1-X5 (in pups and adults) and propose to re-designate them as Ptprz1-V0, Ptprz1-V2, and Ptprz1-V8, respectively. The diversity of RPTPγ and RPTPζ splice variants likely corresponds to distinct signaling functions, in different cellular compartments, during development vs later life. In contrast to previous studies that report divergent RPTPγ and RPTPζ protein expressions in neurons and sometimes in the glia, we observe that RPTPγ and RPTPζ co-express in the somata and processes of almost all HC neurons but not in astrocytes, in all three HC preparations.

Applicability of 2,4-dinitrophenylhydrazine (DNPH) method of protein oxidative damage measurement in the seminal plasma of canine ( Canis lupus familiaris) and stallion ( Equus caballus).

Seminal plasma (SP) proteins are responsible for sperm functional quality. Developing a reliable method to determine the degree of oxidative damage of these proteins is important for establishing semen fertilizing ability. The main aim of the study was to verify the applicability of protein carbonyl derivatives measurement in the SP of canine and stallion, using a method with 2,4-dinitrophenylhydrazine (DNPH). The research material consisted of ejaculates obtained from eight English Springer Spaniels, and from seven half-blood stallions during the breeding and non-breeding season. The content of carbonyl groups in the SP was measured on the basis of the reactions with DNPH. The following reagent variants were used to dissolve protein precipitates: Variant 1 (V1) - 6M Guanidine solution and Variant 2 (V2) - 0.1M NaOH solution. It has been shown that to obtain reliable results for the measurement of protein carbonylated groups in the dog and horse SP, both 6M Guanidine and 0.1M NaOH may be used. A correlation was also found between the number of carbonyl groups and the total protein content in the canine (V1: r = -0.724; V2: r = -0.847) and stallion (V1: r = -0.336; V2: r = -0.334) SP. Additionally, the study showed a higher content (p≤0.05) of protein carbonyl groups in the stallion SP in the non-breeding season compared to the breeding season. The method based on the reaction with DNPH, due to its simplicity and cost effectiveness, appears to be suitable for large-scale application in the determination of the SP proteins oxidative damage in dog and horse semen.

Genetic landscape of patients with ALK-rearranged non–small-cell lung cancer (NSCLC) and response to ceritinib in ASCEND-1 study

ObjectivesTo better understand genetic determinants of response to ceritinib, an exploratory analysis was conducted using tumor biopsies from anaplastic lymphoma kinase (ALK)-rearranged (ALK+) non–small-cell lung cancer (NSCLC) patients treated with ceritinib at doses of ≥ 300 mg in the ASCEND-1 study. MethodsASCEND-1 was an open-label, multicentre, phase 1, dose–escalation and expansion study of ceritinib (fasted) in ALK inhibitor (ALKi)-naïve or ALKi-pretreated patients with locally advanced or metastatic ALK + NSCLC. Biopsies were assayed by next-generation sequencing (NGS) using a Foundation Medicine panel targeting 295 genes. Somatic alterations were correlated with clinical outcome (cut-off 14-Apr-2014). A total of 285 ALK + NSCLC patients were treated with ceritinib at doses ≥ 300 mg. ResultsNGS data were generated for 85 pts (ALKi-pretreated [n = 54]; ALKi-naïve [n = 31]), 57 were collected from patients before exposure to any ALKi. NGS did not detect ALK rearrangement in 14 of 85 patients; several of these ALK NGS negative cases harbored alternative drivers, e.g. EGFR mutation. Of the 71 biopsies with NGS confirmed ALK rearrangement, the most frequently detected rearrangements were EML4-ALK variant 1 (V1) and EML4-ALK V3 (36.6% [26/71] and 32.4% [23/71] respectively). Eight (six crizotinib-pretreated and two pretreated with crizotinib followed by alectinib) of the 21 ALKi-pretreated patients carried a point mutation of the ALK TKD, and had the biopsy collected between 1 and 14 days before ceritinib; with the exception of one patient with a G1202R point mutation, all patients derived clinical benefit from ceritinib treatment.Of the 14 ALKi-naïve patients, ceritinib was effective in almost all patients, including a patient carrying a concomitant ERBB4 and HGF amplification. ConclusionsThis exploratory analysis highlights the potential role of NGS in improving our understanding of response and resistance to ceritinib. It also illustrates that ceritinib is active against almost all ALK resistance mutations found in ALKi-pretreated patients.Trial registration: ClinicalTrials.gov, NCT01283516. Registered January 26, 2011, https://clinicaltrials.gov/ct2/show/NCT01283516

Sensitivity of eight types of ALK fusion variant to alectinib in ALK-transformed cells

Tyrosine kinase inhibitors of anaplastic lymphoma kinase (ALK-TKIs) including alectinib have been the standard therapy against ALK fusion gene-positive non–small cell lung cancers (NSCLCs). Many ALK fusion variants have been identified in NSCLCs, and the predominant variants are echinoderm microtubule-associated protein-like 4-ALK (EML4-ALK) variant 1 (V1), V2 and V3a/b. However, there have been conflicting reports on the clinical responses of these variants to ALK-TKIs, and there are few reports on other less common ALK variants. To examine the influence of ALK variants on the efficacy of ALK-TKIs, we analyzed the sensitivity to alectinib of eight types of ALK variant: three major variants (V1, V2 and V3a) and five less common variants (V4; kinesin family member 5-ALK; kinesin light chain 1-ALK; striatin, calmodulin-binding protein-ALK; and tropomyosin-receptor kinase fused gene-ALK). Analysis was done by cell-free kinase assays using the recombinant proteins and by cell, growth assays using murine Ba/F3 cells expressing ALK variants. The kinase activity of each recombinant protein was significantly inhibited by alectinib. Intracellular ALK phosphorylation levels and its downstream signaling mediators, STAT3 and ERK, were suppressed by alectinib in each ALK variant-expressing Ba/F3 cell. Each cellular proliferation was markedly inhibited by alectinib treatment. There was no significant difference in the IC50 values between cells, with a <3.6-fold difference in responsiveness. In conclusion, these eight ALK variants had similar sensitivity to alectinib in vitro, indicating that it may not be possible to predict the response to alectinib just by determination of the ALK variant type in ALK fusion-positive NSCLCs.

Impact of Wall Materials on Physico-Chemical Properties and Stability of Eggplant Peels Anthocyanin Hydrogels

In this study, eggplant peel extract was used to obtain hydrogels. Two experimental variants were realized by varying the wall materials. Whey proteins isolate (WPI), citrus pectin (P), and sodium carboxymethylcellulose (CMCNa) were used as wall materials. The microcapsules were obtained by the gelation technique, followed by freeze-drying in order to obtain powders. Both experimental variants were analyzed in terms of phytochemical content, antioxidant activity, storage stability, and in vitro digestibility. Additionally, confocal microscopy was used to observe the encapsulation of the bioactive compounds from the eggplant peel extract into the selected matrices. The encapsulation efficiency of the powders varied from 64.67 ± 0.68% for variant 1 (V1) to 96.44 ± 3.43% for variant 2 (V2). Both powders presented high bioactive compound content with high antioxidant activity. V2 showed the highest stability within 28 days of storage, but also in the simulated digestive system.

Single coronary artery Left (SCA L)-Right coronary artery arising from mid-left anterior descending coronary artery: New variant of Lipton classification (SCA L-II) diagnosed by computed tomographic angiography.

Isolated single coronary artery (SCA) is a rare anomaly. Current classification of left and right is further classified based on the course of the anomalous vessel. We report two SCA L cases where right coronary artery (RCA) arose from mid-left anterior descending coronary artery (LAD). Our observation is a variation from the current Lipton classification SCA L Type II where RCA arose from left coronary artery before the LAD, in our cases the RCA arose from mid LAD after the first septal perforator. We believe that this variant should be described as SCA L Type II variant 2 (V2) while the original Lipton classification should be described as SCA L Type II variant 1 (V1).

Monitoring Therapeutic Response and Resistance: Analysis of Circulating Tumor DNA in Patients With ALK+ Lung Cancer

IntroductionDespite initial effectiveness of ALK receptor tyrosine kinase inhibitors (TKIs) in patients with ALK+ NSCLC, therapeutic resistance will ultimately develop. Serial tracking of genetic alterations detected in circulating tumor DNA (ctDNA) can be an informative strategy to identify response and resistance. This study evaluated the utility of analyzing ctDNA as a function of response to ensartinib, a potent second-generation ALK TKI. MethodsPre-treatment plasma was collected from 76 patients with ALK+ NSCLC who were ALK TKI–naive or had received prior ALK TKI, and analyzed for specific genetic alterations. Longitudinal plasma samples were analyzed from a subset (n = 11) of patients. Analysis of pre-treatment tumor biopsy specimens from 22 patients was compared with plasma. ResultsDisease-associated genetic alterations were detected in 74% (56 of 76) of patients, the most common being EML4-ALK. Concordance of ALK fusion between plasma and tissue was 91% (20 of 22 blood and tissue samples). Twenty-four ALK kinase domain mutations were detected in 15 patients, all had previously received an ALK TKI; G1269A was the most prevalent (4 of 24). Patients with a detectable EML4-ALK variant 1 (V1) fusion had improved response (9 of 17 patients; 53%) to ensartinib compared to patients with EML4-ALK V3 fusion (one of seven patients; 14%). Serial changes in ALK alterations were observed during therapy. ConclusionsClinical utility of ctDNA was shown, both at pre-treatment by identifying a potential subgroup of ALK+ NSCLC patients who may derive more benefit from ensartinib and longitudinally by tracking resistance. Prospective application of this technology may translate to improved outcomes for NSCLC patients treated with ALK TKIs.

Rational design of Pleurotus eryngii versatile ligninolytic peroxidase for enhanced pH and thermal stability through structure-based protein engineering.

Versatile peroxidase (VP) from Pleurotus eryngii is a high redox potential peroxidase. It has aroused great biotechnological interest due to its ability to oxidize a wide range of substrates, but its application is still limited due to low pH and thermal stability. Since CiP (Coprinopsis cinerea peroxidase) and PNP (peanut peroxidase) exhibited higher pH and thermal stability than VP, several motifs, which might contribute to their pH and thermal stability, were identified through structure and sequence alignment. Six VP variants incorporating the beneficial motifs were designed and constructed. Most variants were nearly completely inactivated except V1 (Variant 1) and V4. V1 showed comparable activity to WT VP against ABTS, while V4 exhibited reduced activity. V1 displayed improved pH stability than WT VP, at pH 3.0 in particular, whereas the pH stability of V4 did not change a lot. The thermal stabilities of V1 and V4 were enhanced with T50 raised by 3°C. The results demonstrated that variants containing the beneficial motifs of CiP and PNP conferred VP with improved pH and thermal stability.

The anticancer effects of desferrioxamine on human breast adenocarcinoma and hepatocellular carcinoma cells.

N-myc downstream-regulated gene 1 (NDRG1) is defined as metastasis suppressor and can be downregulated in many types of cancers, and reported to be an indication of tumor progression in hepatocellular carcinomas. Several in-vivo and in-vitro studies have demonstrated that iron chelators such as Desferrioxamine (DFO) and 1-10 Phenanthroline (PHEN) are effective antitumor agents. It is suggested that these chelators deliver their antitumor activity by acting on the NDRG1 gene expression. It remains unclear why NDRG1 gene expression affects the tumors differently, or becomes affected differently. We consider that this different effect might be caused by variants. Based on this information, we developed specific primers and probes for NDRG1 mRNA variants using bioinformatics analysis, and investigated how DFO and PHEN affected the dynamics of NDRG1 variant on the cell lines of Human Breast Adenocarcinoma (MCF-7) and Hepatocellular Carcinoma (HepG2) that demonstrate opposite action for the relationship NDRG1-metastasis. We administrated various doses of DFO and PHEN into the cells to monitor cell vitality and proliferation with Real time Cell Analyzer. We analyzed the gene expression levels of study groups with Quantitative RT-PCR as well as relative gene expression. Variants of NDRG1 mRNA were transcriptionally regulated after HepG2 and MCF-7 cells were treated by iron chelators, resulting in domination of NDRG1 mRNA Variant 1 (V1) in the HepG2 calls and domination of NDRG1 mRNA Variant 2 (V2) in the MCF-7 cells. Anti-proliferative and cytotoxic effects were observed in the MCF-7 cells whereas an increased proliferation was present in the HepG2 cells.

Abstract 882: Functional investigation of a novel cancer specific organic anion transporting polypeptide 1B3 variant 1 (OATP1B3 V1) in colon and pancreatic cancer.

Abstract OATP1B3 is a member of the Organic Anion Transporting Polypeptide (OATP) superfamily that mediates the uptake of numerous endogenous and xenobiotic compounds. Initially, OATP1B3 was reported to be expressed exclusively in the normal hepatocytes. Subsequent studies have reported that OATP1B3 is frequently expressed in multiple types of cancer tissues derived from gastrointestinal tract, pancreas, prostate, lung and breast. Some reports have also suggested that OATP1B3 may be associated with differing clinical outcomes. However, so far the biological functions of OATP1B3 in cancer have not been elucidated. In this study, we confirmed that colon and pancreatic cancer cells express variant forms of OATP1B3, different from OATP1B3 wildtype (WT) expressed in normal liver. OATP1B3 variant 1 (V1) is the most prevalent form among the variants containing the alternate exon 2a, instead of exons 1 and 2 as in OATP1B3 WT. The translated protein sequence of OATP1B3 V1 is similar to OATP1B3 WT except lacking the first 28 amino acids at the N-terminus. OATP1B3 V1 has a limited transport activity toward cholecystokin-8 (CCK-8, a prototype OATP1B3 substrate) in contrast to OATP1B3 WT which showed a markedly efficient uptake of CCK-8. Consistent with these results, OATP1B3 V1 was localized mainly in the cytoplasm with a much lower extent of trafficking to the surface membrane compared to OATP1B3 WT. In summary, our results demonstrate that colon and pancreatic cancer cells express variant forms of OATP1B3 with a limited transport activity and different subcellular localization compared to OATP1B3 WT. These observed differences at molecular and functional levels will be important considerations for further investigations of the biological and clinical significance of OATP1B3 expression in cancer. Citation Format: Nilay Thakkar, Kyungbo Kim, Eun Ryoung Jang, Songhee Han, Kyunghwa Kim, Donghern Kim, Nipun Merchant, A. Craig Lockhart, Wooin Lee. Functional investigation of a novel cancer specific organic anion transporting polypeptide 1B3 variant 1 (OATP1B3 V1) in colon and pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 882. doi:10.1158/1538-7445.AM2013-882

A Cancer-Specific Variant of the SLCO1B3 Gene Encodes a Novel Human Organic Anion Transporting Polypeptide 1B3 (OATP1B3) Localized Mainly in the Cytoplasm of Colon and Pancreatic Cancer Cells

OATP1B3 is a member of the OATP (organic anion transporting polypeptides) superfamily, responsible for mediating the transport of numerous endogenous and xenobiotic substances. Although initially reported to be exclusively expressed in the liver, several studies reported that OATP1B3 is frequently expressed in multiple types of cancers and may be associated with differing clinical outcomes. However, a detailed investigation on the expression and function of OATP1B3 protein in cancer has been lacking. In this study, we confirmed that colon and pancreatic cancer cells express variant forms of OATP1B3, different from OATP1B3 wild-type (WT) expressed in the normal liver. OATP1B3 variant 1 (V1), the most prevalent form among the variants, contains alternative exonic sequences (exon 2a) instead of exons 1 and 2 present in OATP1B3 WT. The translated product of OATP1B3 V1 is almost identical to OATP1B3 WT, with exception to the first 28 amino acids at the N-terminus. Exogenous expression of OATP1B3 V1 revealed that OATP1B3 V1 undergoes post-translational modifications and proteasomal degradation to a differing extent compared to OATP1B3 WT. OATP1B3 V1 showed only modest transport activity toward cholecystokin-8 (CCK-8, a prototype OATP1B3 substrate) in contrast to OATP1B3 WT showing a markedly efficient uptake of CCK-8. Consistent with these results, OATP1B3 V1 was localized mainly in the cytoplasm with a much lower extent of trafficking to the surface membrane compared to OATP1B3 WT. In summary, our results demonstrate that colon and pancreatic cancer cells express variant forms of OATP1B3 with only limited transport activity and different subcellular localization compared to OATP1B3 WT. These observed differences at the molecular and functional levels will be important considerations for further investigations of the biological and clinical significance of OATP1B3 expression in cancer.

Regulation of the Unfolded Protein Response by eIF2Bδ Isoforms

Cells respond to a variety of stresses, including unfolded proteins in the endoplasmic reticulum (ER), by phosphorylating a subunit of translation initiation factor eIF2, eIF2α. eIF2α phosphorylation inactivates the eIF2B complex. The inactivation of eIF2B not only suppresses the initiation of protein translation but paradoxically up-regulates the translation and expression of transcription factor ATF-4. Both of these processes are important for the cellular response to ER stress, also termed the unfolded protein response. Here we demonstrate that cellular response resulting from eIF2α phosphorylation is attenuated in several cancer cell lines. The deficiency of the unfolded protein response in these cells correlates with the expression of a specific isoform of a regulatory eIF2B subunit, eIF2Bδ variant 1 (V1). Replacement of total eIF2Bδ with V1 renders cells insensitive to eIF2α phosphorylation; specifically, they neither up-regulate ATF-4 and ATF-4 targets nor suppress protein translation. Expression of variant 2 eIF2Bδ in ER stress response-deficient cells restores the stress response. Our data suggest that V1 does not interact with the eIF2 complex, a requisite for eIF2B inhibition by eIF2α phosphorylation. Together, these data delineate a novel physiological mechanism to regulate the ER stress response with a large potential impact on a variety of diseases that result in ER stress.

Human SIRPA Polymorphism Modulates Macrophage-Mediated Suppression of Human Hematopoiesis

Signal regulatory protein-α (SIRPA) is an immunoglobulin superfamily transmembrane protein with intracellular docking sites for two Src homology domain containing tyrosine phosphatases, and most abundantly expressed in neurons and myeloid cells. SIRPA is a critical immune inhibitory receptor on macrophages. CD47 is a ligand for SIRPA, and CD47 interaction with SIRPA serves as a ‘self-recognition’ that prevents phagocytosis of the cells expressing CD47. Recently, we (Nature immunology 2007) identified polymorphism in murine Sirpa as a critical modulator of engraftment in xenogeneic model of human-to-mouse hematopoietic stem cell transplantation, and non-obese diabetic (NOD) mouse Sirpa polymorphism has far greater reactivity with human CD47 than that of the respective alleles of other strains resulting in effective engraftment of human hematopoietic cells. In addition, as well as the mouse, human SIRPA is highly polymorphic in the IgV domain. Then, we examined whether polymorphism in SIRPA induced the difference for suppressive effect of human macrophage on hematopoiesis. First, we examined sequence alignment of SIRPA IgV domain (exon 3 of SIRPA) of healthy control 18 people. We identified two major variants; 6 people with variant1 (V1) and 12 people with variant2 (V2). The SIRPA amino acid sequences of V1 and V2 are different in 13 residues, and its residues in orthologous position between species that is polymorphic between NOD and other strains as well as between V2 and V1. Next, we examined that whether there is a difference in the effect on hematopoiesis between V1 macrophage and V2 macrophage by long term culture-initiating cells (LTC-IC) assay on MS-5 stromal cells. For macrophage preparation, peripheral mononuclear cells from healthy donors were purified by positive selection using MACS CD14 Micro Beads (Miltenyi Biotec), and they were incubated with M-CSF for 3 days. For LTC-IC assay, 5×102 differentiated macrophages were seeded onto established MS-5 stroma in 96-well tissue culture plates. The next day, human hematopoietic CD34+ cells were seeded at doses of 102 to 5×103 cells per well and cultured for 4 weeks. At the end of the culture, cells were detached and plated into methylcellulose progenitor assays. Macrophage had a suppressive effect on the number of LTC-IC in all cultures. There was tendency that V1 macrophage had a greater suppression compared to V2 macrophage, however the differences between V1 and V2 were marginal (p=0.03). These data suggests that human macrophages have suppressive effect on hematopoiesis, and human SIRPA polymorphism modulates macrophage-mediated suppression of hematopoiesis in allogenic model, likewise in xenogeneic model of human-to-mouse hematopoietic stem cell transplantation. Moreover, SIRPA polymorphism might be related to graft failure in the allogenic hematopoietic stem cell transplantation.

Short stature and decreased insulin-like growth factor I (IGF-I)/growth hormone (GH)-ratio in an adult GH-deficient patient pointing to additional partial GH insensitivity due to a R179C mutation of the growth hormone receptor

Objective Genetic factors play an expanding role in understanding growth hormone (GH) disorders, therefore the German KIMS Pharmacogenetics Study was initiated with the aim of genotyping various GH-/IGF-I-axis-related genes of GH-deficient adult patients to investigate genotype:phenotype relationships and response to GH therapy. Patients and methods 129 consecutively enrolled GH-deficient adult patients were genotyped for variant 1 (V1) of the alternatively spliced noncoding exons in the 5′-untranslated region and for the nine coding exons of the GH receptor (GHR) gene, which obviously play a striking role in the function of the GH-IGF-I-axis. After detection of a heterozygous, non-synonymous mutation R179C in exon 6 in one single patient with acquired GH-deficiency (GHD) in late adulthood, analysis of her clinical data followed, leading to the diagnosis of mild short stature (−1.5 SD). For further endocrine evaluation, five pituitary stimulation tests (arginine) of this patient were statistically compared to stimulation tests (arginine) of ten GH-deficient control patients, retrospectively. Results The formerly in patients with Laron syndrome and idiopathic short stature reported mutation R179C leads to an amino acid change from an arginine residue (codon CGC) to a cysteine residue (codon TGC) in position 179 of the extracellular domain of the GHR. Statistical analysis revealed significant decreased IGF-I/GH 0 ratio ( p = 0.004) and IGF-I/GH max ratio ( p = 0.001) of the index patient compared to the control patients, implying growth hormone resistance of the index patient at the level of the GHR, according to the detected R179C mutation. Conclusions This study reports on the unusual case of a patient with mild short stature, who acquired GHD in late adulthood due to a non-secreting pituitary adenoma and get additionally diagnosed for pre-existing growth hormone insensitivity due to a formerly in two short statured patients described, single, heterozygous, non-synonymous mutation in the GHR. Our findings support the theory that heterozygous mutations in the GHR gene can have mild phenotypical consequences.