[Ambulatory minimally invasive hysterectomy: Limiting factors related to health professionals]

OBJECTIVES

The feasibility of minimally invasive hysterectomy for ambulatory benign pathology has been demonstrated in many international studies. France has a considerable delay of multifactorial origin in this field. The objective of this study is to identify the limiting factors related to health professionals to the realization of minimally invasive ambulatory hysterectomy and to determine possible strategies to increase its rate.

METHODS

This is a cross-sectional survey conducted over 2 months using a self-administered questionnaire sent by email to 180 gynecological surgeons in 2 French regions (Grand Est and Bourgogne-Franche Comté).

RESULTS

A total of 22% of health professionals responded to the survey. The vast majority of practitioners (60%) said they did not carry out ambulatory care by habit. The apprehension of the reaction of the patients (47.5%), the fear of delayed diagnosis of complications (12.5%), the management of pain in the postoperative period (42.5%) also participated in brake of the promotion of ambulatory care.

DISCUSSION

Improvement of the organisation of city and hospital management allowing a better continuity of care (70%), the economic valuation (37.5%) and the increase in the hourly amplitude of the ambulatory surgery unit (5%) would improve the rate of ambulatory care of minimally invasive hysterectomies, according to the gynecologist surgeons surveyed. In addition, a prospective study evaluating the quality of life of patients after ambulatory care of minimally invasive hysterectomy would allow better adherence of health professionals and patients to the ambulatory care project in 70% of cases.

CONCLUSION

The change of mentality of health professionals remains a priority for the promotion of ambulatory surgery in gynecology. Information and communication are therefore essential to the expansion of the ambulatory.

Abstract 2819: Efficacy and safety of the Ad-GM·CAIX dendritic cell-based vaccine in treating in vivo metastatic renal cell carcinoma compared to sunitinib monotherapy and simultaneous vaccine-sunitinib combination therapy

Metastatic clear cell renal cell carcinoma (ccRCC) disease is responsible for significant morbidity and represents the main cause of death in patients with advanced ccRCC. We have developed a novel dendritic cell based vaccine targeting human carbonic anhydrase IX (hCAIX; DC-Ad-GM·CAIX) and compared it with the ccRCC standard-of-care drug, sunitinib as a monotherapy and in simultaneous vaccine-sunitinib combination therapy.

Immunocompetent mice (Balb/c) were orthotopically-transplanted with syngeneic RCC-hCAIXpositive (NPR-IX) tumor cells, immunized, and/or treated with sunitinib at low-dose (5mg/kg/d), high-dose (40mg/kg/d) or untreated. At termination, primary tumor size (weight), lung metastatic burden, hCAIX and immune-markers expression levels were compared.

Mono-immunotherapy with DC-Ad-GM·CAIX vaccine suppressed metastatic tumor growth: the total number of metastatic heterotypic foci (i.e., hCAIX positive and negative foci) following vaccination decreased 2.5 fold compared with untreated mice (P<0.05). When counting only the hCAIX positive metastatic tumor cells, the decrease in the metastatic tumor burden compared to untreated mice was even more pronounced (>10 fold). Vaccination alone resulted in reduced primary tumor burden of RCC-hCAIXpositive cells to <25% of the tumor cell population, with the remaining cells lacking hCAIX expression (hCAIXnegative); there was no significant overall primary tumor reduction compared to untreated mice. In contrast, sunitinib, whether given as high-dose monotherapy or in combination with the vaccine, inhibited the primary orthotopic tumors, achieving 35% (P=0.0001) and 51% (P=1.7e-7) tumor reduction, respectively. However, sunitinib monotherapy was less effective in reducing the metastatic tumor burden compared with the vaccine.

In fact, simultaneous administration of vaccine and sunitinib increased the metastatic tumor burden in heterotypic tumors composed also of hCAIXnegative cells.

In conclusion, this preclinical study demonstrates that (i) the DC-Ad-GM·CAIX vaccine effectively controls both primary and metastatic hCAIXpositive tumors and forms the basis for a phase I trial in metastatic ccRCC patients, which has been initiated at UCLA (http://clinicaltrials.gov number NCT01826877), (ii) Antigen editing with loss of hCAIX is an important immune escape mechanism, (iii) This in vivo study raises caution regarding the use of DC-Ad-GM·CAIX vaccine in simultaneous combination therapies with sunitinib.

Co-corresponding Authors: ASB and JR

Citation Format: Edward N. Rampersaud, Jonathan W. Said, Adrian Bot, Frédéric D. Birkhäuser, Nils Kroeger, Gang Zeng, Fairooz F. Kabbinavar, Antoni Ribas, Allan J. Pantuck, Arie S. Belldegrun, Joseph Riss. Efficacy and safety of the Ad-GM·CAIX dendritic cell-based vaccine in treating in vivo metastatic renal cell carcinoma compared to sunitinib monotherapy and simultaneous vaccine-sunitinib combination therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2819. doi:10.1158/1538-7445.AM2014-2819

Dominant B-cell epitopes from cancer/stem cell antigen SOX2 recognized by serum samples from cancer patients

Human sex determining region Y-box 2 (SOX2) is an important transcriptional factor involved in the pluripotency and stemness of human embryonic stem cells. SOX2 plays important roles in maintaining cancer stem cell activities of melanoma and cancers of the brain, prostate, breast, and lung. SOX2 is also a lineage survival oncogene for squamous cell carcinoma of the lung and esophagus. Spontaneous cellular and humoral immune responses against SOX2 present in cancer patients classify it as a tumor-associated antigen (TAA) shared by lung cancer, glioblastoma, and prostate cancer among others. In this study, B-cell epitopes were predicted using computer-assisted algorithms. Synthetic peptides based on the prediction were screened for recognition by serum samples from cancer patients using ELISA. Two dominant B-cell epitopes, SOX2:52-87 and SOX2:98-124 were identified. Prostate cancer, glioblastoma and lung cancer serum samples that recognized the above SOX2 epitopes also recognized the full-length protein based on Western blot. These B-cell epitopes may be used in assessing humoral immune responses against SOX2 in cancer immunotherapy and stem cell-related transplantation.

Investigating the association of cytoplasmic and nuclear HIF-2 expression with cancer specific survival (CSS) in clear cell renal cell carcinoma

387

Background: Studies support the prognostic importance of HIF-2α for ccRCC. Interestingly, a recent study has implicated HIF-2α as part of a protein translational initiation complex, a cytoplasmic function that goes far beyond its role as a nuclear transcription factor. We hypothesized that both the absolute expression as well as the subcellular localization of HIF-2α would predict clinicopathological features and CSS in ccRCC. Methods: A tissue microarray (TMA) study was conducted on 308 ccRCC patients. Survival differences were investigated with the log rank test and associations with CSS with uni- and multivariate Cox regression analyses. Recursive partition tree analysis was used to identify relevant cutoff values. Results: The median follow-up was 2.29 years (IQR 11.82). The mean percentage of positive cells was 22.45±18.00 and 0.12 ± 0.29 for HIF-2α nuclear (N) and cytoplasmic (C), respectively. High HIF-2α N (cutoff>32%) expression was associated with smaller tumor sizes (p = 0.002) and less advanced Fuhrman grades (p = 0.044). To the contrary, tumors with high HIF-2α C (>0%) more often had lymph node (p = 0.004), distant metastases (p = 0.021), and higher Fuhrman grades (p<0.0001). Univariate analyses showed an association of high HIF-2α N (p = 0.035) with better CSS. This was not found when HIF-2α N was used as a continuous variable (p = 0.067). In contrast, HIF-2α C demonstrated an association with CSS when examined as both a continuous (p < 0.0001) and as a dichotomized variable (p < 0.0001). After adjustment for TNM stage, ECOG PS, and Fuhrman grade, both continuous (p < 0.0001) and dichotomized (p < 0.0001) HIF-2α C variables remained significant predictors of CSS, while neither HIF-2α N variable was retained. The ratio of HIF-2α C/N was the strongest predictor of CSS in multivariate analysis (p = 0.001; HR 4.83 [95% CI: 1.99 – 11.76]). Conclusions: Our investigation suggests an important role for HIF-2α as a cytoplasmic protein translational initiation complex in ccRCC. This novel observation warrants further molecular and genetic studies examining biological pathways that are involved in the tumor promotive properties of HIF-2α in the cytoplasm.

Deletions of chromosomes 3p and 14q molecularly subclassify clear cell renal cell carcinoma

BACKGROUND

The short arm of chromosome 3 (3p) harbors the von Hippel-Lindau (VHL) tumor suppressor gene, and the long arm of chromosome 14 (14q) harbors the hypoxia-inducible factor 1α (HIF-1α) gene. The objective of this study was to evaluate the significance of 3p loss (loss VHL gene) and 14q loss (loss HIF-1α gene) in clear cell renal cell carcinoma (ccRCC).

METHODS

In total, 288 ccRCC tumors underwent a prospective cytogenetic analysis for alterations in chromosomes 3p and 14q. Tumors were assigned to 1 of 4 possible chromosomal alterations: VHL +3p/+14q (VHL wild type [VHL-WT]), VHL +3p/-14q (VHL-WT plus HIF2α [WT/H2]), -3p/+14q (HIF1α and HIF2α [H1H2]), and -3p/-14q (HIF2α [H2]).

RESULTS

Among patients who had loss of 3p, tumors with -3p/-14q (H2) alterations were larger (P = .002), had higher grade (P = .002) and stage (P = .001), and more often were metastatic (P = .029) than tumors that retained 14q (H1H2). All patients who had tumors with -3p/-14q (H2) had worse cancer-specific survival (P = .014), and patients who had localized disease (P = .012) and primary T1 (pT1) tumors (P = .008) had worse recurrence-free survival. In patients who had pT1 tumors, combined 3p/14q loss was an independent predictor of recurrence-free survival (hazard ratio, 11.19; 95% confidence interval, 1.91-65.63) and cancer-specific survival (hazard ratio, 15.93; 95% confidence interval, 3.09-82.16). The current investigation was limited by its retrospective design, single-center experience, and a lack of confirmatory protein analyses.

CONCLUSIONS

Loss of chromosome 3p (the VHL gene) was associated with improved survival in patients with ccRCC, whereas loss of chromosome 14q (the HIF-1α gene) was associated with worse outcomes. The results of the current study support the hypothesis that HIF-1α functions as an important tumor suppressor gene in ccRCC.

Safety and efficacy of dendritic cell immunotherapy with ad-GMCAIX in an immunocompetent preclinical tumor model of renal cell carcinoma

e13045

Background: We have previously reported the successful ex vivo generation of hCAIX-specific cytotoxic T lymphocytes (CTLs) by adenoviral (Ad) transduction of the GMCAIX fusion protein in dendritic cells (DC). We then produced GMP-grade material (NIH-RAID program, NSC 740833). Now we test, for the first time, the in vivo anti-tumor activity of DC-Ad-GMCAIX against renal cell carcinoma (RCC) in a unique immunocompetent mouse tumor model. Methods: Tumor growth inhibition and specificity were studied in BALB/c mice s.c. transplanted with either syngeneic RENCA cells transduced with hCAIX (URCAIX) or with non-hCAIX-expressing RENCA cells (RENCA). In a tumor prevention model, cohorts of mice were first immunized s.c. twice with DC-Ad-GMCAIX, DC-Ad-null, or no DCs, followed by tumor challenge with s.c. transplantation of URCAIX or RENCA cells. In an intervention model, tumors were first established and then immunotherapy was employed. Tumor volume and body weight were regularly assessed. Partial necropsy, immunohistochemistry of harvested tumors, and complete blood count were performed at termination of each study. Results: In the prevention model, URCAIX tumor growth was specifically and significantly inhibited for 15 days (p<0.0001). At termination, median growth inhibition reached 79% (113 vs. 531 mm3) and half of the mice remained tumor-free. In the intervention model, DC-Ad-GMCAIX-treated mice showed specific and significant growth inhibition of URCAIX tumors for 8 days (p<0.0018) with a median growth inhibition reaching 60% (487 vs. 1,205 mm3). The threshold of 15% weight loss was delayed in the therapeutic groups of both models (p<0.0167). No treatment-related weight loss or organ toxicity was observed. hCAIX staining was absent or minimally present in URCAIX-tumors that evaded DC-Ad-GMCAIX therapy. Conclusions: DC-Ad-GMCAIX therapy in a novel immunocompetent mouse model demonstrated, for the first time, both tumor prevention and growth inhibition of established RCC tumors without evidence of systemic toxicity. These studies form the basis for first-in-human clinical trial in patients with advanced RCC.

Gain of chromosome 8q is associated with metastases and poor survival of patients with clear cell renal cell carcinoma

BACKGROUND

The aim of this study was to evaluate the prevalence of chromosome 8q gain in clear cell renal cell carcinoma (CCRCC) and to correlate the findings with tumor phenotype and disease-specific survival (DSS).

METHODS

The tumor karyotypes of 336 consecutive patients with CCRCC were prospectively evaluated with classical cytogenetic analysis. Chromosome 8q status was correlated with clinicopathological variables, and its impact on DSS was evaluated.

RESULTS

Gain of 8q occurred in 28 tumors (8.3%). Gain of 8q was associated with a higher risk of regional lymph node (21.4% vs 6.2%, P = .011) and distant metastases (50.0% vs 24.4%, P = .006), and greater tumor sizes (P = .030). Patients with gain of 8q had a 3.22-fold increased risk of death from CCRCC (P < .001). In multivariable analysis, gain of 8q was identified as an independent prognostic factor (hazard ratio, 2.37; P = .006). The concordance index of a multivariable base model increased significantly following inclusion of 8q gain (P = .0015).

CONCLUSIONS

Gain of chromosome 8q occurs in a subset of CCRCCs and is associated with an increased risk of metastases and death from CCRCC. Because the proto-oncogene c-MYC is among the list of candidate genes located on 8q, our data suggest that these tumors may have unique pathways activated, which are associated with an aggressive tumor phenotype. If confirmed, defining tumors with gain of 8q may assist in identifying patients who would benefit for specific c-MYC inhibitors or agents that target the MAPK/ERK (mitogen-activated protein kinase) pathway.

Abstract 1563: In vivo safety and efficacy of a novel dendritic cell based Ad-GMCAIX vaccine with activity against renal cell carcinoma

Carbonic anhydrase IX (CAIX) expression is constitutively up-regulated in clear cell renal cell carcinoma (ccRCC) due to loss of the VHL gene. Its up-regulation in ccRCC and low expression levels in normal tissues led us to develop an immunotherapeutic approach targeting the CAIX tumor antigen. We previously reported the successful generation and ex vivo priming of CAIX-specific, MHC restricted cytotoxic T lymphocytes (CTLs) by adenoviral (Ad) transduction of the GM-CAIX fusion protein in dendritic cells (DCs). Our current study tests, for the first time, the in vivo anti-tumor activity of DC-Ad-GMCAIX in preventing and intervening in the growth of RCC in immunocompetent mouse models. Tumor growth was studied in BALB/c mice transplanted s.c. with either the syngeneic CAIX-expressing RCC cell line RENCA-CAIX (PRCAIX) or the non-CAIX-expressing parental RENCA line. In the preventative model, cohorts of mice were s.c. immunized twice 6 days apart with either DC-Ad-GMCAIX, DC-Ad-null, or no DC transplantation, followed by s.c. challenge with PRCAIX or RENCA lines 12 days later. In the interventional model, tumors were first established and then immunotherapy was employed. At the end of each study, tumors were harvested, and partial necropsy, immunohistochemistry, and complete blood count were performed. DC-Ad-GMCAIX expressed in vivo the hCAIX protein that primed CTLs to specifically target hCAIX expressed by the PRCAIX line. In the preventative model, PRCAIX tumor growth was specifically and significantly inhibited by DC-Ad-GMCAIX for 15 days (all p&lt;0.0001), reaching 79% median growth inhibition at termination (113 vs. 531 mm3). In the therapeutic cohort, time to 15% weight loss was significantly delayed (log-rank test p&lt;0.001). Half of the mice in the treatment cohort did not develop tumors. The results were confirmed by a repeated study (inhibition for 15 days; all p&lt;0.0001; 7/8 mice without tumor). In the interventional model, DC-Ad-GMCAIX-vaccinated mice demonstrated a specific and significant growth inhibition of PRCAIX-tumors for 8 days, with 60% median growth inhibition at termination (all p&lt;0.0018; 487 vs. 1,205 mm3). In the therapeutic cohort, time to 15% weight loss was significantly delayed (log-rank test p&lt;0.0167). No vaccine-related weight loss or organ toxicity was observed. hCAIX staining was absent or only minimally present in PRCAIX-tumors that grew despite therapy with DC-Ad-GMCAIX, compared to strong staining in the negative control groups. In conclusion, DC-Ad-GMCAIX therapy is capable of in vivo generation of CAIX specific CTLs in immunocompetent mice, leading to a significant inhibition of RCC tumor growth without systemic toxicity. Additional studies are being done to analyze the immune response, and the differential global gene and miRNA expression of tumor cells resistant to CAIX-based therapy. NCI RAID Initiative NSC 740833. § co-corresponding.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1563. doi:1538-7445.AM2012-1563

Benzodiazepines in epilepsy: pharmacology and pharmacokinetics

Benzodiazepines (BZDs) remain important agents in the management of epilepsy. They are drugs of first choice for status epilepticus and seizures associated with post-anoxic insult and are also frequently used in the treatment of febrile, acute repetitive and alcohol withdrawal seizures. Clinical advantages of these drugs include rapid onset of action, high efficacy rates and minimal toxicity. Benzodiazepines are used in a variety of clinical situations because they have a broad spectrum of clinical activity and can be administered via several routes. Potential shortcomings of BZDs include tolerance, withdrawal symptoms, adverse events, such as cognitive impairment and sedation, and drug interactions. Benzodiazepines differ in their pharmacologic effects and pharmacokinetic profiles, which dictate how the drugs are used. Among the approximately 35 BZDs available, a select few are used for the management of seizures and epilepsy: clobazam, clonazepam, clorazepate, diazepam, lorazepam and midazolam. Among these BZDs, clorazepate has a unique profile that includes a long half-life of its active metabolite and slow onset of tolerance. Additionally, the pharmacokinetic characteristics of clorazepate (particularly the sustained-release formulation) could theoretically help minimize adverse events. However, larger, controlled studies of clorazepate are needed to further examine its role in the treatment of patients with epilepsy.

Cancers as wounds that do not heal: differences and similarities between renal regeneration/repair and renal cell carcinoma

Cancers have been described as wounds that do not heal, suggesting that the two share common features. By comparing microarray data from a model of renal regeneration and repair (RRR) with reported gene expression in renal cell carcinoma (RCC), we asked whether those two processes do, in fact, share molecular features and regulatory mechanisms. The majority (77%) of the genes expressed in RRR and RCC were concordantly regulated, whereas only 23% were discordant (i.e., changed in opposite directions). The orchestrated processes of regeneration, involving cell proliferation and immune response, were reflected in the concordant genes. The discordant gene signature revealed processes (e.g., morphogenesis and glycolysis) and pathways (e.g., hypoxia-inducible factor and insulin-like growth factor-I) that reflect the intrinsic pathologic nature of RCC. This is the first study that compares gene expression patterns in RCC and RRR. It does so, in particular, with relation to the hypothesis that RCC resembles the wound healing processes seen in RRR. However, careful attention to the genes that are regulated in the discordant direction provides new insights into the critical differences between renal carcinogenesis and wound healing. The observations reported here provide a conceptual framework for further efforts to understand the biology and to develop more effective diagnostic biomarkers and therapeutic strategies for renal tumors and renal ischemia.

Mistaken identifiers: gene name errors can be introduced inadvertently when using Excel in bioinformatics

Background

When processing microarray data sets, we recently noticed that some gene names were being changed inadvertently to non-gene names.

Results

A little detective work traced the problem to default date format conversions and floating-point format conversions in the very useful Excel program package. The date conversions affect at least 30 gene names; the floating-point conversions affect at least 2,000 if Riken identifiers are included. These conversions are irreversible; the original gene names cannot be recovered.

Conclusions

Users of Excel for analyses involving gene names should be aware of this problem, which can cause genes, including medically important ones, to be lost from view and which has contaminated even carefully curated public databases. We provide work-arounds and scripts for circumventing the problem.

Properties of switch-like bioregulatory networks studied by simulation of the hypoxia response control system

A complex bioregulatory network could be more easily comprehended if its essential function could be described by a small "core" subsystem, and if its response characteristics were switch-like. We tested this proposition by simulation studies of the hypoxia response control network. We hypothesized that a small subsystem governs the basics of the cellular response to hypoxia and that this response has a sharp oxygen-dependent transition. A molecular interaction map of the network was prepared, and an evolutionarily conserved core subsystem was extracted that could control the activity of hypoxia response promoter elements on the basis of oxygen concentration. The core subsystem included the hypoxia-inducible transcription factor (HIFalpha:ARNT heterodimer), proline hydroxylase, and the von Hippel-Lindau protein. Simulation studies showed that the same core subsystem can exhibit switch-like responses both to oxygen level and to HIFalpha synthesis rate, thus suggesting a mechanism for hypoxia response promoter element-dependent responses common to both hypoxia and growth factor signaling. The studies disclosed the mechanism responsible for the sharp transitions. We show how parameter sets giving switch-like behavior can be found and how this type of behavior provides a foundation for quantitative studies in cells.

Regulation of HIF prolyl hydroxylases by hypoxia-inducible factors

Hypoxia and induction of hypoxia-inducible factors (HIF-1alpha and HIF-2alpha) is a hallmark of many tumors. Under normal oxygen tension HIF-alpha subunits are rapidly degraded through prolyl hydroxylase dependent interaction with the von Hippel-Lindau (VHL) tumor suppressor protein, a component of E3 ubuiquitin ligase complex. Using microarray analysis of VHL mutated and re-introduced cells, we found that one of the prolyl hydroxylases (PHD3) is coordinately expressed with known HIF target genes, while the other two family members (PHD1 and 2) did not respond to VHL. We further tested the regulation of these genes by HIF-1 and HIF-2 and found that siRNA targeted degradation of HIF-1alpha and HIF-2alpha results in decreased hypoxia-induced PHD3 expression. Ectopic overexpression of HIF-2alpha in two different cell lines provided a much better induction of PHD3 gene than HIF-1alpha. In contrast, we demonstrate that PHD2 is not affected by overexpression or downregulation of HIF-2alpha. However, induction of PHD2 by hypoxia has HIF-1-independent and -dependent components. Short-term hypoxia (4 h) results in induction of PHD2 independent of HIF-1, while PHD2 accumulation by prolonged hypoxia (16 h) was decreased by siRNA-mediated degradation of HIF-1alpha subunit. These data further advance our understanding of the differential role of HIF factors and putative feedback loop in HIF regulation.

Predicting survival in patients with metastatic kidney cancer by gene-expression profiling in the primary tumor

To identify potential molecular determinants of tumor biology and possible clinical outcomes, global gene-expression patterns were analyzed in the primary tumors of patients with metastatic renal cell cancer by using cDNA microarrays. We used grossly dissected tumor masses that included tumor, blood vessels, connective tissue, and infiltrating immune cells to obtain a gene-expression "profile" from each primary tumor. Two patterns of gene expression were found within this uniformly staged patient population, which correlated with a significant difference in overall survival between the two patient groups. Subsets of genes most significantly associated with survival were defined, and vascular cell adhesion molecule-1 (VCAM-1) was the gene most predictive for survival. Therefore, despite the complex biological nature of metastatic cancer, basic clinical behavior as defined by survival may be determined by the gene-expression patterns expressed within the compilation of primary gross tumor cells. We conclude that survival in patients with metastatic renal cell cancer can be correlated with the expression of various genes based solely on the expression profile in the primary kidney tumor.

GoMiner: a resource for biological interpretation of genomic and proteomic data

We have developed GoMiner, a program package that organizes lists of 'interesting' genes (for example, under- and overexpressed genes from a microarray experiment) for biological interpretation in the context of the Gene Ontology. GoMiner provides quantitative and statistical output files and two useful visualizations. The first is a tree-like structure analogous to that in the AmiGO browser and the second is a compact, dynamically interactive 'directed acyclic graph'. Genes displayed in GoMiner are linked to major public bioinformatics resources.

Solid renal tumor severity in von Hippel Lindau disease is related to germline deletion length and location

von Hippel Lindau disease (VHL) is an autosomal dominant familial cancer syndrome linked to alteration of the VHL tumor suppressor gene. Affected patients are predisposed to develop pheochromocytomas and cystic and solid tumors of the kidney, CNS, pancreas, retina, and epididymis. However, organ involvement varies considerably among families and has been shown to correlate with the underlying germline alteration. Clinically, we observed a paradoxically lower prevalence of renal cell carcinoma (RCC) in patients with complete germline deletion of VHL. To determine if a relationship existed between the type of VHL deletion and disease, we retrospectively evaluated 123 patients from 55 families with large germline VHL deletions, including 42 intragenic partial deletions and 13 complete VHL deletions, by history and radiographic imaging. Each individual and family was scored for cystic or solid involvement of CNS, pancreas, and kidney, and for pheochromocytoma. Germline deletions were mapped using a combination of fluorescent in situ hybridization (FISH) and quantitative Southern and Southern blot analysis. An age-adjusted comparison demonstrated a higher prevalence of RCC in patients with partial germline VHL deletions relative to complete deletions (48.9 vs. 22.6%, p=0.007). This striking phenotypic dichotomy was not seen for cystic renal lesions or for CNS (p=0.22), pancreas (p=0.72), or pheochromocytoma (p=0.34). Deletion mapping revealed that development of RCC had an even greater correlation with retention of HSPC300 (C3orf10), located within the 30-kb region of chromosome 3p, immediately telomeric to VHL (52.3 vs. 18.9%, p <0.001), suggesting the presence of a neighboring gene or genes critical to the development and maintenance of RCC. Careful correlation of genotypic data with objective phenotypic measures will provide further insight into the mechanisms of tumor formation.

The contribution of VHL substrate binding and HIF1-alpha to the phenotype of VHL loss in renal cell carcinoma

Clear-cell renal carcinoma is associated with inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene. VHL is the substrate recognition subunit of an E3 ligase, known to target the alpha subunits of the HIF heterodimeric transcription factor for ubiquitin-mediated degradation under normoxic conditions. We demonstrate that competitive inhibition of the VHL substrate recognition site with a peptide derived from the oxygen degradation domain of HIF1alpha recapitulates the tumorigenic phenotype of VHL-deficient tumor cells. These studies prove that VHL substrate recognition is essential to the tumor suppressor function of VHL. We further demonstrate that normoxic stabilization of HIF1alpha alone, while capable of mimicking some aspects of VHL loss, is not sufficient to reproduce tumorigenesis, indicating that it is not the critical oncogenic substrate of VHL.

Expression of novel alternatively spliced isoforms of the oct-1 transcription factor

Analysis of the alternatively spliced isoforms of the human and mouse oct-1 genes, combined with their exon-intron structure, show a high level of evolutionary conservation between these two species. The differential expression of several oct-1 isoforms was examined by reverse transcription-polymerase chain reaction performed on the 3' region of the murine oct-1 cDNA. Variations in the relative levels and patterns of expression of the isoforms were found among different tissues. Three novel isoforms originating from the 3'-distal region of oct-1, were isolated and sequenced: Two were derived from testis, and one from myeloma cells. Splicing out of different exons as revealed in the structure of these isoforms results in reading frameshifts that presumably lead to the expression of shortened Oct-1 proteins, with distinct C-terminal tails. Altogether, six out of the eight known murine oct-1 isoforms may have distinct C-termini, implying that these multiple tails have different functional roles in cellular differentiation and physiology.

Cloning, sequencing and expression of two isoforms of the murine oct-1 transcription factor

Oct-1 is a ubiquitously expressed regulatory gene of the POU domain family. The Oct-1 protein binds to the octamer motif present in the control regions of a variety of genes such as the immunoglobulins, histone H2B and snRNAs. To learn about Oct-1 and its possible role in B-cell maturation, we have used oct-2 cDNA to screen a murine pre-B cell, cDNA library. Two cDNA clones were identical in their POU-homeo box DNA binding domain, but differed in their 3'-region. Whereas one clone (oct-1a) was very similar to its human oct-1 homologue, the other (oct-1b), contained an additional 72 bp sequence (designated E1) at the serine threonine rich coding region (position 1485 of the human oct-1), and a deletion of another 72 bp sequence (designated E2) downstream (position 1920). These changes preserve the protein reading frame. DNA blot analysis indicates that murine oct-1 is a single copy gene and that the two oct-1 isoforms oct-1 is expressed as a large approximately 10 kb transcript in all the cell are generated by alternative RNA splicing. RNA blots showed that oct-1 is expressed as a large approximately 10 kb transcript in all the cell lines tested. PCR analysis of the E1 and E2 72 bp regions, indicated the presence of a third isoform containing both E1 and E2 (Oct-1c). Oct-1a and Oct-1b were present in all cell types examined, but the level of expression was lower in liver and spleen as compared to testis, thymus and kidney. The ratio of Oct-1b to Oct-1a ranged between 0.2 to 0.5, for all tissues examined except for testis which expressed higher amounts of oct-1b and/or oct-1c. Our findings thus show that the pattern of expression of the oct-1 gene is more complex than hitherto thought.

Primary structure of dystrophin-related protein

Dystrophin-related protein (DRP or 'utrophin') is localized in normal adult muscle primarily at the neuromuscular junction. In the absence of dystrophin in Duchenne muscular dystrophy (DMD) patients, DRP is also present in the sarcolemma. DRP is expressed in fetal and regenerating muscle and may play a similar role to dystrophin in early development, although it remains to be determined whether DRP can functionally replace dystrophin in adult tissue. Previously we described a 3.5-kilobase complementary DNA clone that exhibits 80 per cent homology to the C-terminal domain of dystrophin. This sequence identifies a 13-kilobase transcript that maps to human chromosome 6 (refs 2, 11). Antibodies raised against the gene product identify a polypeptide with a relative molecular mass of about 400K in all tissues examined. To investigate the relationship between DRP and dystrophin in more detail, we have cloned and sequenced the whole DRP cDNA. Homology between DRP and dystrophin extends over their entire length, suggesting that they derive from a common ancestral gene. Comparative analysis of primary sequences highlights regions of functional importance, including those that may mediate the localization of DRP and dystrophin in the muscle cell.

Molecular cloning of the bovine thymopoietin gene and its expression in different calf tissues: evidence for a predominant expression in thymocytes

Thymopoietin (TP), a 49 amino acid peptide, is regarded as a thymic hormone, secreted specifically by some epithelial cells in the thymic stroma and exerting a multitude of effects on maturation and function of T lineage cells. As part of our study on the molecular biology of TP, we isolated cDNA clone coding for a bovine TP precursor and used it as a probe to analyze the presence of mRNA coding for TP in different tissues. The cDNA clone reported here is 1.1 kb long and contains an open reading frame (ORF) of 741 bp which corresponds to 247 amino acids. The 147 bp coding for the entire bovine TP are at the 5' end of the ORF. A DNA fragment coding for amino acids 1-42 of bovine TP was used as a probe to look for hybridizable RNA sequences, extracted from various calf tissues, by the S1 nuclease protection method. Our results indicate that the TP gene is expressed predominantly in lymphatic tissues. Lymphatic tissues with the highest levels observed were thymocytes and not thymic stroma. Lower, but still significant, amounts were present in tonsils, neck lymph nodes, and small intestine (probably because of its lymphatic part--the Peyer's patches), whereas cultured thymic stromal cells, spleen tissue and peripheral blood mononuclear cells displayed a low level of TP mRNA. The TP gene expression in all other (non-lymphatic) tissues tested, was weak, barely detectable or virtually absent. However, the cerebellum could be singled out with relatively strong expression of TP mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)