Adcitmer® , a new CD56-targeting monomethyl auristatin E-conjugated antibody, is a potential therapeutic approach in Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive skin cancer, whose tumour cells often express CD56. While immune checkpoint inhibitors constitute a major advance for treating patients with MCC with advanced disease, new therapeutic options are still urgently required.

OBJECTIVES

To produce and evaluate the therapeutic performance of a new antibody-drug conjugate (Adcitmer^® ) targeting CD56 in preclinical models of MCC.

METHODS

CD56 expression was evaluated in a MCC cohort (immunohistochemistry on a tissue microarray of 90 tumour samples) and MCC cell lines. Interaction of an unconjugated CD56-targeting antibody with CD56⁺ MCC cell lines was investigated by immunohistochemistry and imaging flow cytometry. Adcitmer^® product was generated by the bioconjugation of CD56-targeting antibody to a cytotoxic drug (monomethyl auristatin E) using the McSAF Inside^® bioconjugation process. The chemical properties and homogeneity of Adcitmer^® were characterized by hydrophobic interaction chromatography. Adcitmer^® cytotoxicity was evaluated in vitro and in an MCC xenograft mice model.

RESULTS

Similar to previous reports, CD56 was expressed by 66% of MCC tumours in our cohort, confirming its relevance as a therapeutic target. Specific binding and internalization of the unconjugated CD56-targeting antibody was validated in MCC cell lines. The high homogeneity of the newly generated Adcitmer^® was confirmed by hydrophobic interaction chromatography. The CD56-mediated cytotoxicity of Adcitmer^® was demonstrated in vitro in MCC cell lines. Moreover, Adcitmer^® significantly reduced tumour growth in a MCC mouse model.

CONCLUSIONS

Our study suggests that Adcitmer^® should be further assessed as a therapeutic option in patients with MCC, as an alternative therapy or combined with immune checkpoint inhibitors.

Protecting effect of PrP codons M142 and K222 in goats orally challenged with bovine spongiform encephalopathy prions

Breeding towards genetic resistance to prion disease is effective in eliminating scrapie. In sheep, classical forms of scrapie have been eradicated almost completely in several countries by breeding programs using a prion protein (PrP) gene (PRNP) amino acid polymorphism. For goats, field and experimental studies have provided evidence for several amino acid polymorphisms that are associated with resistance to scrapie, but only limited data are available concerning the susceptibility of caprine PRNP genotypes to BSE. In this study, goat kids representing five PRNP genotypes based on three polymorphisms (M142, Q211 and K222 and the wild type I142, R211 and Q222) were orally challenged with bovine or goat BSE. Wild type goats were killed with clinical signs between 24-28 months post inoculation (mpi) to both challenges, and goats with genotype R/Q211 succumbed between 29-36 mpi. I/M142 goats developed clinical signs at 44-45 mpi and M/M142 goats remained healthy until euthanasia at 48 mpi. None of the Q/K222 goats showed definite clinical signs. Taken together the highest attack ratios were seen in wild type and R/Q211 goats, and the lowest in I/M142, M/M142 and Q/K222. In all genotype groups, one or more goats remained healthy within the incubation period in both challenges and without detectable PrP deposition in the tissues. Our data show that both the K222 and M142 polymorphisms lengthen the incubation period significantly compared to wild type animals, but only K222 was associated with a significant increase in resistance to BSE infection after oral exposure to both BSE sources.

Trichodysplasia spinulosa: a polyomavirus infection specifically targeting follicular keratinocytes in immunocompromised patients

Trichodysplasia spinulosa (TS) is a rare skin disease, caused by a specific polyomavirus, occurring in immunocompromised patients. The pathophysiological mechanisms of TS are not yet fully understood. By using polymerase chain reaction and skin biopsy immunostaining we report evidence, in a paediatric case, of follicular keratinocytes being the primary target of trichodysplasia spinulosa-associated polyomavirus.

Functional expression of sv40 in normal human prostatic epithelial and fibroblastic cells - differentiation pattern of nontumorigenic cell-lines

To study mesenchymal-epithelial interactions associated with the normal and pathological human prostate, we have developed a model of well differentiated human prostate epithelial and fibroblastic cells. Normal human prostatic cells, either of epithelial or fibroblastic origins were successfully transfected with SV40 and strains with extended lifespan were selected until the crisis was reached, within 20 and 30 passages for the epithelial and fibroblastic cells, respectively. Only a few clones emerged from the crisis: PNT1A (Cussenot et al: J Urol 143: 881-886, 1991), PNT1B and PNT2 epithelial cell lines. Successful immortalisation was achieved only with SV40 expressing both large T and small t oncogenes, while attempts to immortalise with a vector expressing SV40 large T alone have given a few strains showing no extended lifespan and no cells which overcame the crisis. A PNT2 subclone named PNT2-LSD which developed spontaneously (less serum dependent) was selected, characterised and included in the analysed series. The epithelial cell lines displayed a differentiation pattern which has been classified as follows (from high to low): PNT2>PNT2-LSD>PNT1A>PNT1B. Differentiation features studied were (i) the colony-forming ability of the PNT2 and PNT2-LSD compared to PNT1A and PNT1B, (ii) their respective doubling time of 39, 29, 30 and 28 hours, (iii) their decreasing serum dependency, (iv) the expression of cytokeratin 19 (a feature of well differentiated luminal cells of the glandular prostate) for PNT2 and PNT2-LSD. Furthermore, the mesenchymal derived pflsv1 cells were confirmed to be of fibroblastic nature. None of the cell lines analysed showed any tumourigenicity in nude mice over a period of 12 months. Serum deprivation and direct steroid withdrawal during the culture triggered cell death by apoptosis, an event which could be overcome by EGF stimulation, particularly for the well differentiated PNT2 cells. This interesting characteristic, which is similar to the high apoptotic rate observed ipl vivo for normal prostate, particularly after castration should lead, together with the other properties of these cell lines, to a better understanding of the biology of the different cell compartments involved in the progression of prostate towards neoplasia.

Protective effect of the T112 PrP variant in sheep challenged with bovine spongiform encephalopathy

Sheep with an ARQ/ARQ PRNP genotype at codon positions 136/154/171 are highly susceptible to experimental infection with bovine spongiform encephalopathy (BSE). However, a number of sheep challenged orally or intracerebrally with BSE were clinically asymptomatic and found to survive or were diagnosed as BSE-negative when culled. Sequencing of the full PRNP gene open reading frame of BSE-susceptible and -resistant sheep indicated that, in the majority of Suffolk sheep, resistance was associated with an M112T PRNP variant (TARQ allele). A high proportion (47 of 49; 96%) of BSE-challenged wild-type (MARQ/MARQ) Suffolk sheep were BSE-infected, whereas none of the 20 sheep with at least one TARQ allele succumbed to BSE. Thirteen TARQ-carrying sheep challenged with BSE are still alive and some have survival periods equivalent to, or greater than, reported incubation periods of BSE in ARR/ARR and VRQ/VRQ sheep.

Apoptotic pulsed dendritic cells induce a protective immune response against Toxoplasma gondii

Infection with the intracellular protozoan parasite Toxoplasma gondii may cause severe sequelae in foetuses and life-threatening neuropathy in immunocompromised patients. We recently reported that vaccination with T. gondii-pulsed dendritic cells induces protective humoral and cellular immune responses against this intracellular pathogen in CBA/J mice. We assessed the feasibility of using a nonlive vaccine, by inducing the apoptosis of T. gondii-pulsed dendritic cells before injecting them into mice. Apoptosis was induced by culturing cells to confluence. We investigated whether these apoptotic T. gondii-pulsed dendritic cells elicited an immune response in vivo. Some studies have shown that immunization with apoptotic cells leads to the activation of innate and adaptive immune mechanisms. Our results are consistent with apoptotic cells having immunomodulatory properties in a model of parasite infection. We showed that the adoptive transfer of T. gondii-pulsed apoptotic dendritic cells elicited humoral and cellular Toxoplasma-specific immune responses with a Th1/Th2 profile, and conferred specific protection. The protective immune response induced was independent of inducible HSP70 production by apoptotic dendritic cells.

Regulation of ubiquitin–proteasome system, caspase enzyme activities, and extracellular proteinases in rat soleus muscle in response to unloading

In the present study, we determined the impact of 5 and 10 days of muscle deconditioning induced by hindlimb suspension (HS) on the ubiquitin-proteasome system of protein degradation and caspase enzyme activities in rat soleus muscles. A second goal was to determine whether activities of matrix metalloproteinase-2/9 (MMP-2/9) and urokinase-type/tissue-type plasminogen activator (PAs) were responsive to HS. As expected, HS led to a pronounced atrophy of soleus muscle. Level of ubiquitinated proteins, chymotrypsin-like activity of 20S proteasome, and Bcl-2-associated gene product-1 protein level were all transitory increased in response to 5 days of HS. These changes may thus potentially account for the decrease in muscle mass observed in response to 5 days of HS. Caspase-3 activity was significantly increased throughout the experimental period, whereas activities of caspase-6, another effector caspase, and caspase-9, the mitochondrial-dependent activator of both caspase-3 and -6, were only increased in response to 10 days of HS. This suggests that caspase-3 may be regulated through mitochondrial-independent and mitochondrial-dependent mechanisms in response to HS. Finally, MMP-2/9 activities remained unchanged, whereas PAs activities were increased after 5 days of HS. Overall, these data suggest that time-dependent regulation of intracellular and extracellular proteinases are important in setting the new phenotype of rat soleus muscle in response to HS.

Clinical relevance of genetic instability in prostatic cells obtained by prostatic massage in early prostate cancer

We investigated whether genetic lesions such as loss of heterozygosity (LOH) are detected in prostatic cells obtained by prostatic massage during early diagnosis of prostate cancer (CaP) and discussed their clinical relevance. Blood and first urine voided after prostatic massage were collected in 99 patients with total prostate-specific antigen (PSA) between 4 and 10 ng ml⁻¹, prior to prostate biopsies. Presence of prostatic cells was confirmed by quantitative RT–PCR analysis of PSA mRNA. Genomic DNA was analysed for LOH on six chromosomal regions. One or more allelic deletions were found in prostatic fluid from 57 patients analysed, of whom 33 (58%) had CaP. Sensitivity and specificity of LOH detection and PSA free to total ratio <15% for positive biopsy were respectively 86.7 and 44% (P=0.002) for LOH, and 55 and 74% (P=0.006) for PSA ratio <15%. Analysis of LOH obtained from prostatic tumours revealed similar patterns compared to prostatic fluid cells in 86% of cases, confirming its accuracy. The presence of LOH of urinary prostatic cells obtained after prostatic massage is significantly associated with CaP on biopsy and may potentially help to identify a set of patients who are candidates for further prostate biopsies.

[Collections of human biological resources for research purposes: from regulations to the need of a guide of good collection practices]

PURPOSE

In France, collections of human biological resources are regulated by the "Bioethics Law", currently in revision. Hence, we analyse the regulatory and ethical issues of these practices in the context of scientific research. The ultimate aim of such collections is to improve biological and medical knowledge.

CURRENT KNOWLEDGE AND KEY POINTS

We think that the French regulatory system is quite complicated and non-explicit for "collection holders". The multiplicity of legal texts concerning this activity has made their application difficult, especially in the absence of application decrees. The project amending the actual law has clarified the legal status of collections but it did not shed light on the status of human body detached parts. Furthermore, the text is still very far from the international bioethical recommendations, and does not reflect the actual collection's implementation.

FUTURE PROSPECTS AND PROJECTS

The establishment of a guideline of Good Collection Practices, based on clear principles, should help to simplify the situation, especially when it is imbedded in the regulation and linked to control procedures. It would allow a balance between collective interests and the protection of individuals, taking into account of the international highly competitive scientific and economical constraints. The major issue is to preserve and to perpetuate the existing and future collections because of their precious value as an important tool for biomedical knowledge. The efficiency of a regulation depends on its legibility and accessibility, two requirements that seem to determine the acceptance of the regulatory tool and its application allowing subsequently to reach fairness in proceedings.

Segregation analysis of prostate cancer in France: evidence for autosomal dominant inheritance and residual brother-brother dependence

Four segregation analyses concerning prostate cancer (CaP), three conducted in the United States and one in Northern Europe, have shown evidence for a dominant major gene but with different parameter estimates. A recent segregation analysis of Australian pedigrees has found a better fit of a two-locus model than single-locus models. This model included a dominantly inherited increased risk that was greater at younger ages and a recessively inherited or X-linked increased risk that was greater at older ages. Recent linkage analyses have led to the detection of at least 8 CaP predisposing genes, suggesting a complex inheritance and genetic heterogeneity. To assess the nature of familial aggregation of prostate cancer in France, segregation analysis was conducted in 691 families ascertained through 691 CaP patients, recruited from three French hospitals and unselected with respect to age at diagnosis, clinical stage or family history. This mode of family inclusion, without any particular selection of the probands, is unique, as probands from all previous analyses were selected according to various criteria. Segregation analysis was carried out using the logistic hazard regressive model, as incorporated in the REGRESS program, which can accommodate a major gene effect, residual familial dependences of any origin (genetic and/or environmental), and covariates, while including survival analysis concepts. Segregation analysis showed evidence for the segregation of an autosomal dominant gene (allele frequency of 0.03%) with an additional brother-brother dependence. The estimated cumulative risks of prostate cancer by age 85 years, among subjects with the at-risk genotype, were 86% in the fathers' generation and 99% in the probands' generation. This study supports the model of Mendelian transmission of a rare autosomal dominant gene with high penetrance, and demonstrates that additional genetic and/or common sibling environmental factors are involved to account for the familial clustering of CaP.

General review of maximal aerobic velocity measurement at laboratory. Proposition of a new simplified protocol for maximal aerobic velocity assessment

The maximal aerobic velocity concept developed since eighties is considered as either the minimal velocity which elicits the maximal aerobic consumption or as the "velocity associated to maximal oxygen consumption". Different methods for measuring maximal aerobic velocity on treadmill in laboratory conditions have been elaborated, but all these specific protocols measure V(amax) either during a maximal oxygen consumption test or with an association of such a test. An inaccurate method presents a certain number of problems in the subsequent use of the results, for example in the elaboration of training programs, in the study of repeatability or in the determination of individual limit time. This study analyzes 14 different methods to understand their interests and limits in view to propose a general methodology for measuring V(amax). In brief, the test should be progressive and maximal without any rest period and of 17 to 20 min total duration. It should begin with a five min warm-up at 60-70% of the maximal aerobic power of the subjects. The beginning of the trial should be fixed so that four or five steps have to be run. The duration of the steps should be three min with a 1% slope and an increasing speed of 1.5 km x h(-1) until complete exhaustion. The last steps could be reduced at two min for a 1 km x h(-1) increment. The maximal aerobic velocity is adjusted in relation to duration of the last step.

Establishment and characterisation of ovine blood monocyte-derived cell lines

Studies of the important functions in host defense assured by macrophages, both as functional elements and as potential targets for intracellular pathogens, are often inhibited by the lack of a source of large numbers of uniform, well-characterised cells. To address this lack for ovine studies, we have established cell lines from spontaneously-proliferating adherent mononuclear cells from sheep blood. Eight such lines which have been continuously cultured for over 400 passages have phagocytic activities and cytochemical characteristics indicating that they retain the nature of mononuclear phagocytes. They display typical functional membrane proteins such as CD14, Fc receptors and MHC class II. Such cells can facilitate in vitro studies of pathogen-monocyte interactions and can furnish copious amounts of cells for transfer experiments.

Evaluation of androgen, estrogen (ER alpha and ER beta), and progesterone receptor expression in human prostate cancer by real-time quantitative reverse transcription-polymerase chain reaction assays

Steroid hormones can have profound effects on prostate tumor development making it important to define steroid receptor expression in prostate tissues. For this purpose, androgen receptor (AR) and estrogen receptor (ER alpha and ER beta) expression was quantified in 12 clinically localized and 11 hormone-refractory sporadic prostate tumors, using real-time quantitative reverse transcription-PCR assays. To gain more insight into hormone-responsiveness, estrogen-regulated progesterone receptor (PGR) and androgen-regulated prostatic acid phosphatase (PAP) mRNA levels were also quantified. There is a decrease in expression of ER beta in both clinically localized and hormone-refractory tumors relative to normal prostate tissues. Moreover, hormone-refractory tumors display a decreased expression of ER alpha and an increased expression of AR. There is a positive association between ER alpha, ER beta, and PGR expression (P < 0.0001) and a negative association between AR and the androgen-regulated gene PAP expression in hormone-refractory tumors. Taken together, these data indicate that, although increased expression of the AR gene might play a key role in endocrine treatment failure, it cannot be considered as the sole actor of this unresolved dilemma, and abnormalities in ER alpha and/or ER beta expression may also modulate the growth response of prostate cancer to hormone withdrawal. Our results also suggest that ER alpha and ER beta expression status could be used to identify advanced prostate tumor patients who may respond to antiestrogen therapy.

Noninvasive detection of genetic instability in cells from prostatic secretion as a marker of prostate cancer

We present a clinical and molecular study of a series of specific loss of heterozygosity (LOH) indicators which, together with PSA, increase the predictability of cancer in early prostate cancer patients. Considering a positive biopsy as the standard reference, the testing parameters for LOH testing are better than the PSA F/T ratio (<25%), suggesting that this noninvasive approach to detecting early prostate cancer could be very useful as a new tool to optimize the indications for iterative prostate biopsies.

PCAP is the major known prostate cancer predisposing locus in families from south and west Europe

To date four prostate cancer predisposing loci have been mapped: HPC1 (Hereditary Prostate Cancer 1) on 1q24-25, PCaP (Predisposing for Cancer Prostate) on 1q42.2-43, CAPB (Cancer Prostate and Brain) on 1p36, and HPCX on Xq27-28. We examined evidence for linkage to those loci in 64 families from south and west Europe. Genotyping of three (six for PCaP) markers encompassing the candidate regions were performed on 221 individuals including 159 affected patients. The resulting data were analysed using both parametric and non parametric linkage methods. No significant evidence of linkage to HPC1, CAPB, or HPCX was found either in the whole population or when pedigrees were stratified according to criteria specific to each locus. By contrast, results in favour of linkage to PCaP locus were observed with maximum multipoint NPL and HLOD scores of 2.8 (P = 0.0026) and 2.65 respectively. Homogeneity analysis performed with multipoint LOD scores gave an estimated proportion of families with linkage to this locus up to 50%. Particularly, families with an earlier age at diagnosis (< or = 65-years-old) contributed significantly to the evidence of linkage with a maximum multipoint NPL score of 2.03 (P = 0.024). Those results suggest that PCaP is the most frequent known locus predisposing to hereditary prostate cancer cases from families from south and west Europe.

In vivo model mimicking natural history of dog prostate cancer using DPC-1, a new canine prostate carcinoma cell line

BACKGROUND

Dog prostate cancer is usually considered to be highly relevant to human prostate cancer. We report the isolation of a new canine prostate cancer epithelial cell line designated DPC-1.

METHODS

Primary cultures were established from a canine poorly differentiated prostatic adenocarcinoma. Population doubling time was determined by counting nuclei after cell lysis. Tumorigenicity was assessed in nude mice and in one adult immunodeficient dog. Immunoscintigraphy was performed in both models using a monoclonal antibody (mAb) raised against the [44-62] sequence of human PSMA.

RESULTS

DPC-1 cells have a rapid growth in vitro (doubling time, 27 hr) which is not stimulated by androgens. In addition, DPC-1 displays immunoreactivity to human PSA and PSMA. DPC-1 was found to be highly tumorigenic not only in nude mice but also for the first time after orthotopic seeding in an immunodeficient dog. This allograft mimicked, in a compressed form, the aggressive biological behavior of spontaneous dog prostate adenocarcinoma. Immunoscintigraphy using a (131)Iodine-labeled PSMA mAb clearly visualized induced tumors in nude mice and in the dog allograft.

CONCLUSIONS

This study suggests that DPC-1 may constitute a powerful model for assessing new diagnostic and/or therapeutic tools in the management of prostate cancer.

Hereditary prostate cancer and other genetic predispositions to prostate cancer

The incidence of prostate cancer (CaP) and its increase in the last 10 years vary both from country to country and according to the ethnic group, with the highest incidence reported for Afro-Americans and the lowest for Asian men. To date, only three risk factors have been established for CaP: age; familial aggregation of CaP, and ethnic origins. No dietary or environment-related cause has been established. However, some variations in endogenous genetic factors may help explain differences in risk among ethnic groups or geographic areas. Similarly, certain genetic polymorphisms of genes encoding for 5alpha-reductase, androgen receptor or vitamin D, have been associated with different levels of CaP risk, and could explain the variations observed between populations. Different studies support the view that familial CaP may truly be hereditary, and not due to a similar lifestyle. Thus, familial inheritance is a parameter that needs to be considered in recommending screening for high-risk families. Indeed, when 1, 2, and 3 first-degree relatives are affected, the relative risk of first-degree relatives of CaP patients may increase to 2, 5, and 11%, respectively. Some familial forms appear to be associated with transmission of a rare putative dominant gene with a high penetrance (88% at age 85), with the cumulative proportion of CaP attributable to this gene being more marked for younger patients (a 43 versus a 34% risk of CaP appearing before the age of 55 versus 70 years). Using this transmission model and linkage analysis, a predisposing locus on chromosome 1q24-25 (HPC-1) has been described. Moreover, recessive and X-linked transmission has been suggested, showing that a large proportion of familial CaP may not be due to segregation of a few major gene mutations, but rather to familial sharing of alleles at many loci, each contributing to a small increase in cancer risk. Candidate genes may be the same suppressor genes that are involved in other cancers and in sporadic CaP.

Early-onset hereditary prostate cancer is not associated with specific clinical and biological features

BACKGROUND

Familial prostate cancer (CaP) accounts for 15-20% of all CaP, and hereditary CaP for 5-10% of patients. Few data are available concerning their clinical and biological features.

METHODS

We compared diagnostic modalities, age, clinical stage, PSA, and tumor grade at diagnosis in CaP patients according to familial CaP profile: hereditary (HR) (> or =3 CaP), familial nonhereditary (FNH) (= 2 CaP), and sporadic CaP. Only cases diagnosed after January 1, 1987 (PSA-available period) were included. We considered as informative sporadic (IS) cases those probands with 2+ nonaffected brothers at least 50 years old. Finally, 267 CaP (230 probands and 37 affected brothers) were studied.

RESULTS

In multivariate analysis, the only specific parameter significantly associated with HR and FNH CaP was early age at diagnosis; mean ages were 65.3 years (HR), 67 years (FNH), and 70.9 years (IS) (P < 0. 0001). No significant difference was observed concerning clinical stage, PSA, and tumor grade. In addition, diagnostic modalities were similar in the three groups.

CONCLUSIONS

Our data confirm the occurrence of early-onset CaP in hereditary families. Although the clinical and biological presentation of HR CaP remains controversial, the lack of specific features observed in our study leads us to conclude that there is no difference in the aggressiveness of the disease in hereditary compared to sporadic CaP.

Early onset and familial predisposition to prostate cancer significantly enhance the probability for breast cancer in first degree relatives

Genetic predisposition accounts for >/=10% of all cancer of the prostate (CaP) and is therefore considered a major risk factor, together with age and ethnic origin. Several epidemiological studies have suggested that familial clustering of CaP may be associated with an increased frequency of breast and other cancers among relatives. In order to correlate the incidence of CaP with prevalence of breast and other cancers, we have performed uni- and multi-variate analyses on 691 complete pedigrees including probands, who were consecutive patients with confirmed CaP treated in three French urological departments. We have shown a significantly higher risk (RR = 2.3, p = 0.01) to develop breast cancer in families with multiple than in those with a single CaP. Risk of observing other types of cancer within these families was not significant. We then calculated the breast cancer risk in early onset prostate cancer families, and observed a relative risk that is even more significant (RR = 5.5, p = 0.002). Furthermore, the risk was >30 times that a proband's mother have breast cancer if CaP occurred below 55 years of age, rather than after 75 years (p = 0.003). This study has therefore shown for the first time, the relatively high penetrance for breast cancer in relatives of early onset CaP patients.

Changes in cortisol and testosterone levels and T/C ratio during an endurance competition and recovery

BACKGROUND

To describe the evolution of cortisol and testosterone levels and testosterone/cortisol (T/C) ratio in long-distance runners during a relay competition and during the three days following the competition.

METHODS

Two teams of four relayers (one male, one female) took part into this six-hour relay race. Hormonal control during the race was made possible thanks to saliva sampling during rest periods at each relay. The runners were subelite runners, (VO2max = 67.0 ml x min(-1) x kg(-1) in males and 56.8 ml x min(-1) x kg(-1) in females).

RESULTS

During the race, cortisol levels reached approximately 1.5-fold basal levels. These levels remained high till late evening, (higher than morning values, when normal resting levels are 4 to 6-folds lower). Surprisingly, wakening levels during the following days were lower than resting levels. Testosterone did not vary in females; then, male values only are reported. During the race they decreased gradually and remained low till night. During the following three days, testosterone levels were higher than resting day levels. The T/C ratio amplifies these variations: low during the race till retiring, (currently associated with a catabolic tendency) and reversely high during the following three days (associated with a high anabolic tendency).

CONCLUSIONS

As expected, a catabolic tendency occurs during a long distance run (increase in cortisol level followed by a drop in testosterone level). More surprising is the high anabolic tendency noted during the recovery period (low cortisol and high testosterone levels).

Androgen receptor localisation and turnover in human prostate epithelium treated with the antiandrogen, casodex

In vitro models of normal and malignant human prostate are currently limited to a few well established cell lines that, with a single exception (LNCaP), fail to express the androgen receptor (AR) - a common characteristic of prostatic epithelium grown in culture. To investigate the molecular mechanism of action of the non-steroidal antiandrogen Casodex (bicalutamide) against wild-type AR, we have established a transient AR expression model in non-tumorigenic prostate cells of both epithelial and mesenchymal origin. In this model, both dihydrotestosterone and Casodex can effectively transport the AR protein into the nucleus of prostate cells. Whereas the natural ligand, dihydrotestosterone, stabilises the receptor, the AR is rapidly degraded at a nuclear location when the transfected cells are treated with Casodex. In contrast, whereas the mutant AR in the LNCaP line is also degraded on Casodex treatment over the same time period, its intracellular targeting is defective.

Gene transfer to urethral strictures in rabbits: a preliminary report

OBJECTIVE

To assess the rationale for virus-mediated gene transfer into the urethra in vivo and in vitro, using a rabbit model, as this is an attractive approach to prevent recurrence after the endoscopic management of urethral strictures.

MATERIALS AND METHODS

Primary cultures of rabbit urethral stromal cells were infected with adenoviral and retroviral solutions carrying a nucleus-targeted beta-galactosidase (beta-Gal) reporter gene (respectively 109 and 107 plaque-forming units/mL). In addition, to mimic the human clinical situation, a model was developed of thermally induced stricture in rabbit urethra which produced fibrotic stenosis within 15 days. Using a prototype channelled balloon catheter, these strictures were endoscopically dilated and then instilled with the beta-Gal adenoviral or retroviral constructs.

RESULTS

The application of recombinant adenovirus and retrovirus harbouring a nucleus-targeted beta-Gal reporter gene to cultured rabbit urethral stromal cells resulted in a high transduction efficiency of up to 90% and 96%, respectively. Five days after infection, histochemical and immunohistochemical staining of the strictured urethrae showed a 3% rate of transfection targeted to stromal cells within the fibrosis, confirmed by polymerase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry, immunohistochemistry and PCR.

CONCLUSION

These results represent the first report of endoscopic adenovirus and retrovirus-mediated gene transfer to the urethra. Although at a low rate, transduction reached stromal cells transmurally within the induced strictures and was site-specific.

[Genetic analysis of familial prostatic cancer: localization of a gene predisposing to prostatic cancer (PCaP) on chromosome 1q 42.2-43]

OBJECTIVES

To conduct genetic linkage analysis in order to localize predisposition genes for hereditary prostate cancer (CaP), as various epidemiological studies have demonstrated a family aggregation in 15 to 25% of cases, and the development of hereditary forms in 5 to 10% of cases of CaP.

MATERIAL AND METHODS

A genetic study on 47 French and German families included 122 patients and 72 subjects considered to be healthy after PSA assay. This study was conducted by linkage analysis of 364 microsatellite markers distributed throughout the genome (on average every 10 cM).

RESULTS

Parametric and nonparametric linkage analysis identified a locus on chromosome 1q 42.2-43, which could be with a gene predisposing to CaP (called PCaP). The primary site was confirmed by several markers, using 3 different genetic models. The maximum LOD score (probability of linkage between the locus and the disease) on two-point analysis was 2.7 for the D1S2785 marker. Parametric and nonparametric multipoint analysis provided an HLOD score and an NPL score of 2.2 and 3.1, respectively (with P = 0.001). Heterogeneity analysis with calculations of LOD scores by multipoint analysis estimated that up to 50% of hereditary CaPs were related to this locus, with a heterogeneity probability of 157/1. Analysis of a subgroup of 9/47 families characterized by early onset CaP (before the age of 60 years) confirmed the very high probability of localization of a predisposition gene at locus 1q42.2-43 for these families (multipoint LOD score and NPL score of 3.31 and 3.32, respectively; with P = 0.001).

CONCLUSION

The identification of predisposition genes will eventually allow identification within certain families of those subjects who have inherited the genetic abnormality and who therefore present a high risk of CaP. It will then be possible to perform targeted screening of CaP in order to diagnose CaP as early as possible.

[Epidemiology of familial prostatic cancer: 4-year assessment of French studies]

OBJECTIVES

(1) To determine the frequency of familial (at least 2 cases) and hereditary forms of prostate cancer (CaP), (2) to define the results according to the patient's age at diagnosis, as various epidemiological studies have demonstrated a possible familial aggregation of CaP in about 15 to 25% of cases. Carter's familial segregation study (P.N.A.S. 1992, 89, 3367-71) showed that a genetic predisposition, with autosomal dominant transmission, could be responsible for 9% of all cases of prostate cancer.

MATERIAL AND METHODS

We conducted a systematic genealogy study of patients suffering from newly diagnosed CaP or followed for known CaP in 3 French urological centres, by means of questionnaires completed by the patients. Subsequently, a national collection of families with at least 2 cases of CaP identified families with hereditary forms of CaP. Hereditary cases were considered to be those presenting at least: one CaP in three 1st degree relatives, or 3 cases over 3 generations in the same branch of the family (paternal or maternal), or finally 2 early cases before the age of 55 years. Statistical analysis used the univariate logistic regression test between family status and the medical centre or the patient's age at diagnosis.

RESULTS

From July 1994 onwards, we included 801 patients (all stages combined) in the systematic study and 110 patients (13.7%) were excluded (refusal to participate, advanced age). For 691 of the families studied (Brest: 225, Nancy: 249, Paris St Louis: 217), we observed 32 (14.2%), 29 (11.6%), 37 (17.1%) of familial forms (mean: 14.2%) and 11 (4.9%), 6 (2.4%), 8 (3.7%) of hereditary forms (mean: 3.6%), respectively (no significant differences between centres). Analysis of the results according to age at diagnosis of CaP also showed a higher incidence of familial (significant difference) and hereditary forms (limit of significance) for CaP occurring at a younger age (before 65 years). The national collection collected a total of 624 familial forms of CaP, including 236 (37.8%) cases of hereditary forms; 115 families were informative for the genetic linkage study.

CONCLUSION

These results confirm the data of earlier studies, revealing about 15 to 25% of familial forms of CaP and 5 to 10% of hereditary forms. Similarly, the systematic study confirmed the earlier onset of CaP in patients with a genetic predisposition. These data therefore encourage systematic questioning of patients for a family history of CaP in order to propose targeted screening of high-risk subjects in the families concerned and to intensify identification of hereditary forms in order to investigate the genes involved.

Vitamin D receptor polymorphisms as markers in prostate cancer

Polymorphisms in the vitamin D receptor (VDR) gene have been analyzed in several studies for an association with prostate cancer (PCA) and odds ratios (OR) > or = 3 have been observed in study populations from North America. We studied three polymorphisms in the VDR gene (poly-A microsatellite, TaqI and FokI RFLPs) in 105 controls and 132 sporadic PCA cases from France and in a collection of families from Germany and France. The polymorphisms near the 3' end of the gene were in linkage disequilibrium with an almost complete coincidence of the short poly-A alleles and t (presence of the restriction site) of the TaqI polymorphism, (contingency tables, P<0.0001). An association was found by logistic regression for the poly-A between PCA and the heterozygous genotype (S/L; S < 17, L > or = 17, OR=0.44, 95% confidence interval, CI=0.198-0.966, P=0.041). OR was lower in patients < or = 70 years old and patients with a Gleason score > or = 6. The Tt genotype of the TaqI RFLP also showed an association with PCA (OR=0.5, CI=0.27-0.92, P=0.026). This association was also stronger for patients < or = 70 years old (OR=0.31, CI=0.15-0.63, P=0.001). The risk alleles were S and t alleles as indicated by the OR of the homozygotes, although these were not significant. The FokI RFLP at the 5' end of the gene did not reveal any association (P>0.7). While some association studies differ between Europe and North America, our present findings with the VDR gene agree with those from North America, indicating a weak but general role of the VDR in PCA susceptibility.

FGF7/KGF triggers cell transformation and invasion on immortalised human prostatic epithelial PNT1A cells

Fibroblast growth factor 7 (FGF7/KGF) is synthesized exclusively by fibroblasts in normal tissues; it acts as a potent mitogen on epithelial cells, through interaction with the FGF7-specific receptor FGFR2/IIIb. To examine the importance of this growth factor both to prostate physiology and to prostate-cancer progression, we have tested the exogenous effect of FGF7. Thus, by mimicking the paracrine pathway (on proliferation, growth in soft agar and invasion) on the human prostatic epithelial cell line PNT1A positively checked for FGFR2/IIIb expression, FGF7 significantly enhanced cell proliferation at an optimal concentration of 7.5 x 10(-11) M, but no significant invasion or growth in soft agar were observed. To confirm FGF7 properties on human prostatic epithelial cells, we constitutively expressed FGF7 by transfecting PNT1A cells with FGF7-cDNA. The FGF7-transfected clones, PNT1A/ FGF7-T5 and PNT1A/FGF7-T6, were stable and expressed FGF7. Analysis of the FGF7-autocrine loop on the non-tumorigenic epithelial cells PNT1A showed acquired invasive potential in in vitro extracellular-matrix migration assays, specifically inhibited by an FGF7-neutralizing antibody, and over-expressed factors implicated in the migration process: the metalloproteinase MMP-1 and the plasminogen activator uPA. Taken together, these results demonstrate a role for FGF7 in triggering invasion of human prostatic epithelial cells. Furthermore, these FGF7-transfected clones exhibited functional and physiological differences from the original PNT1A cell line: anchorage-independent growth, growth in serum-free media and increased proliferation. These data confirm the oncogenic function of FGF7 in prostate progression potentially acting through paracrine and/or autocrine regulatory pathways.

FGF7/KGF triggers cell transformation and invasion on immortalised human prostatic epithelial PNT1A cells

Fibroblast growth factor 7 (FGF7/KGF) is synthesized exclusively by fibroblasts in normal tissues; it acts as a potent mitogen on epithelial cells, through interaction with the FGF7-specific receptor FGFR2/IIIb. To examine the importance of this growth factor both to prostate physiology and to prostate-cancer progression, we have tested the exogenous effect of FGF7. Thus, by mimicking the paracrine pathway (on proliferation, growth in soft agar and invasion) on the human prostatic epithelial cell line PNT1A positively checked for FGFR2/IIIb expression, FGF7 significantly enhanced cell proliferation at an optimal concentration of 7.5 x 10(-11) M, but no significant invasion or growth in soft agar were observed. To confirm FGF7 properties on human prostatic epithelial cells, we constitutively expressed FGF7 by transfecting PNT1A cells with FGF7-cDNA. The FGF7-transfected clones, PNT1A/ FGF7-T5 and PNT1A/FGF7-T6, were stable and expressed FGF7. Analysis of the FGF7-autocrine loop on the non-tumorigenic epithelial cells PNT1A showed acquired invasive potential in in vitro extracellular-matrix migration assays, specifically inhibited by an FGF7-neutralizing antibody, and over-expressed factors implicated in the migration process: the metalloproteinase MMP-1 and the plasminogen activator uPA. Taken together, these results demonstrate a role for FGF7 in triggering invasion of human prostatic epithelial cells. Furthermore, these FGF7-transfected clones exhibited functional and physiological differences from the original PNT1A cell line: anchorage-independent growth, growth in serum-free media and increased proliferation. These data confirm the oncogenic function of FGF7 in prostate progression potentially acting through paracrine and/or autocrine regulatory pathways.

An experimental model of bulbar urethral stricture in rabbits using endoscopic radiofrequency coagulation

OBJECTIVES

To develop an experimental model of endoscopic urethral stricture mimicking the human clinical situation.

METHODS

Twenty-four New Zealand male rabbits were included. Eighteen animals (study group) underwent videourethroscopy with a pediatric resectoscope, and a 3 to 5-mm-long circumferential electrocoagulation of the bulbar urethra was performed, without postoperative urinary diversion. Six animals underwent the same procedure without application of electrocautery (control group). Each animal was assessed for urethral stricture on day 15 and day 30 by videourethroscopy and voiding cystogram. Among the study group, 8 animals were killed on day 15 and 10 on day 30 for histologic evaluation. All the control animals were killed on day 30 for histologic examination.

RESULTS

Nine animals (50%) in the study group developed a significant bulbar stricture (reducing the lumen by more than 50%) at day 15. Histologic examination confirmed the presence of hyalin fibrosis mutilating the urethral wall. No spontaneous improvement of the stricture was observed on day 30. None of the controls developed urethral stricture, and histologic examination showed a normal urethra in each case.

CONCLUSIONS

Endoscopic electrocoagulation of the urethral wall provides a reproducible model of stricture in the rabbit.

Ureteral gene transfer to porcine induced strictures using endourologic delivery of an adenoviral vector

PURPOSE

Direct gene transfer to the ureter is an attractive approach to prevent restenosis after endourologic management of ureteral strictures. We therefore assessed the rationale for adenovirus-mediated gene transfer in the ureter in vitro and in vivo using a porcine model.

MATERIALS AND METHODS

Primary cultures of porcine ureteral epithelial and stromal cells were infected with an adenoviral solution carrying a nucleus-targeted beta-Galactosidase (beta-Gal) reporter gene (6.5 10(8) pfu/ml.). In addition, in order to mimic the human clinical situation, we have devised a model of thermally-induced stricture in porcine ureter which produced tight fibrotic stenosis within 8 days. Using a purposely designed channelled balloon catheter prototype, these strictures were endoscopically dilated and then instilled with the same beta-Gal adenoviral construction.

RESULTS

Application of recombinant adenovirus harboring a nucleus-targeted beta-Gal reporter gene to cultured porcine urothelial and stromal cells resulted in high transduction efficiency of up to 99% and 84% respectively. Seven days after infection, X-Gal staining of the strictured ureters demonstrated transfection up to 2 mm. depth within the fibrosis, confirmed by polymerase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry (X-Gal staining) and PCR.

CONCLUSION

This data represents the first report of adenovirus-mediated gene transfer to the ureter. It remained site specific by endourologic retrograde clinically applicable techniques.

(CAG)nCAA and GGN repeats in the human androgen receptor gene are not associated with prostate cancer in a French-German population

Alleles of the CAG and the GGC repeat in the first exon of the human androgen receptor (AR) gene have been shown to be associated with the risk of (advanced) prostate cancer. These studies had been carried out in the United States. We have analysed these polymorphisms in a French-German collection of 105 controls, 132 sporadic cases, and a sample of prostate cancer families comprising 85 affected and 46 not affected family members. The allele distributions were very similar in all four groups and chi square statistics on contingency tables did not detect any significant differences. The relative risk (odds ratio, OR) were calculated using logistic regression and did not reach significance despite sufficient numbers of patients and controls. Typical results were OR = 1.007; 95% Confidence Interval (CI) 0.97-1.1, P = 0.87 for CAG as continuous variable and OR = 1.2 (95% CI 0.7-2.0), P = 0.47 for CAG classes < 22 and > = 22 repeats. Similar results were obtained for subgroups defined by age or Gleason score. We conclude that these polymorphisms can not be used as predictive parameters for prostate cancer in the French or German population.

Upregulation of endothelin 1 and its precursor by IL-1beta, TNF-alpha, and TGF-beta in the PC3 human prostate cancer cell line

Increasing evidence indicates that endothelin 1 (ET-1) is implicated in prostate tumour progression. However, data on ET-1 regulation in human prostate and prostate cancer cell lines are lacking. In this study, regulation of ET-1 and its precursor big ET-1, using PC3 cells, a human bone metastatic prostatic carcinoma cell line, was addressed. ET-1 and big ET-1 assays demonstrated greater secretion of both peptides in the presence of 10% fetal calf serum (FCS) as compared with 0.5% FCS. Incubation of PC3 cells in the absence and presence of various cytokines and growth factors known to be implicated in prostate stroma-epithelium interactions, revealed that IL-6, FGF7/KGF and FGF2/bFGF had no effect on ET-1 and big ET-1 secretion, whereas interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) stimulated their secretion in a concentration-dependent manner. Binding experiments indicated the presence of specific ET-1 receptors in PC3 cells: Kdapp = 1.1 x 0.2 x 10(-10)M, Bmax = 2660 +/- 390 sites/cell. Data analysis demonstrated the presence of only the ETA receptor subtype in PC3 cells. In conclusion, our results indicate that the implication of ET-1 in prostate cancer is likely to be mediated via paracrine/autocrine control of cell factors.

Adenovirus-mediated gene transfer in dog prostate: a preclinical study of a relevant model system for gene therapy of human prostatic cancer

This present study evaluates the potential of adenovirus-mediated gene transfer (AMGT) to the prostate of normal laboratory beagles. Many morphological and histological similarities can be noted between dog and human prostate. Moreover, dogs can spontaneously develop prostate cancer with a clinical and biological outcome identical to that in man. Firstly we showed the capacity of human adenovirus to infect canine prostatic cells in vitro. Secondly, we injected transrectally in the dogs' prostates 2x10(9) plaque forming units of a first generation recombinant adenovirus vector harboring the reporter gene beta-galactosidase (AdRSVbetagal). Seven days after the adenoviral delivery, we observed expression of the transgene in both prostates, and exclusively in epithelial cells. Despite a cellular and a humoral immune response, the infusion appeared safe, since the dogs had no fever and presented no urinary symptoms. This study constitutes the first evaluation of AMGT in dog prostate and provides a basis for gene therapy treatment of prostate carcinoma-bearing patients.

Thermal radiofrequency induced porcine ureteral stricture: a convenient endourologic model

PURPOSE

To establish a reliable model of iatrogenic ureteral stricture mimicking the human clinical situation in order to experiment with new site-specific endourologic treatment concepts.

MATERIALS AND METHODS

After cystoscopic insertion of a 7F right ureteral catheter, we induced external thermal radiofrequency injury to the right upper third ureter at low power setting (10 W) using an open surgical approach in 13 pigs. Three pigs considered as controls underwent the same procedure without application of electrocautery. All 16 animals were initially assessed at 8 days; 3 study animals and the 3 controls were followed for 6 weeks.

RESULTS

No control animals had strictures. Significant upper third ureteral strictures with marked hydronephrosis where achieved in all study animals after a mean interval of 9 days, as evidenced by ultrasound examination and retrograde ureteropyelography. Endoscopic retrograde access to these strictures was always possible (mean length 1.4 cm.). Histologic examination displayed severe disorganization of the muscular layer by dense fibrosis composed of collagen bundles with few scattered fibroblasts. No spontaneous improvement of the stricture was observed in the 3 animals reassessed at 6 weeks.

CONCLUSIONS

Externally applied radiofrequency energy to porcine ureter provides a reproducible model of fibrous stricture resembling its clinical counterparts.

Evaluation and clinical value of neuroendocrine differentiation in human prostatic tumors

BACKGROUND

Prostate cancer, like other solid tumors, is a rather heterogeneous entity. More than 50% of all malignant prostatic tumors contain neuroendocrine-like cells, which cannot be attributed to small cell prostatic carcinoma or carcinoid-like tumors, which represent only 1-2% of all prostatic malignancies. Several investigators have reported that histopathologic determination of neuroendocrine differentiation in prostate carcinomas may have prognostic implications, while others have not confirmed these results. However, on the basis of experimental data, neuroendocrine-like cells appear to be involved in the emergence of androgen-independent cells and could be a target for new prostate cancer therapeutic strategies.

METHODS

The literature on the neuroendocrine phenotype of prostatic carcinoma is reviewed. This review summarizes most of the accumulated experimental and clinical data on the neuroendocrine phenotype in prostate cancer. We analyze the putative functions of neuroendocrine-like cells in prostate cancer progression and discuss the place of neuroendocrine phenotype biomarkers as diagnostic and prognostic factors in prostate cancer.

RESULTS

The fact that focal, patchy and heterogeneous clusters of neuroendocrine-like cells are frequently identified in organ-confined prostatic carcinoma probably accounts for the various evaluations of the predictive value of neuroendocrine histological patterns for the clinical outcome at this stage of the disease. The amount of neuroendocrine cells required to produce a detectable elevation in plasma chromogranin A has not yet been determined, but it is correlated with the number of chromogranin A-positive neuroendocrine (NE) cells. Despite the obvious current limitations of the application of neuropeptides as a serological test, this overview will try to more accurately define the possible roles of specific neuropeptides as prostatic cancer markers in diagnostic and monitoring protocols. The plasma chromogranin A level, in comparison with neuron-specific enolase (NSE), chromogranin B (CBG), pancreastatin, or secretogranin levels, appears to be the most useful neuroendocrine marker for determination of neuroendocrine differentiation of advanced prostatic adenocarcinoma.

CONCLUSIONS

Future studies on neuroendocrine should confirm whether neuroendocrine biomarkers, especially the chromogranin family of peptides, can be used as prognostic markers during the course of prostate cancer or for the selection of patients suitable for evaluation of new antineoplastic drugs known to be active against specific and aggressive subpopulations of tumor cells.

Predisposing gene for early-onset prostate cancer, localized on chromosome 1q42.2-43

There is genetic predisposition associated with >=10% of all cancer of the prostate (CaP). By means of a genomewide search on a selection of 47 French and German families, parametric and nonparametric linkage (NPL) analysis allowed identification of a locus, on chromosome 1q42.2-43, carrying a putative predisposing gene for CaP (PCaP). The primary localization was confirmed with several markers, by use of three different genetic models. We obtained a maximum two-point LOD score of 2.7 with marker D1S2785. Multipoint parametric and NPL analysis yielded maximum HLOD and NPL scores of 2.2 and 3.1, respectively, with an associated P value of . 001. Homogeneity analysis with multipoint LOD scores gave an estimate of the proportion of families with linkage to this locus of 50%, with a likelihood ratio of 157/1 in favor of heterogeneity. Furthermore, the 9/47 families with early-onset CaP at age <60 years gave multipoint LOD and NPL scores of 3.31 and 3.32, respectively, with P = .001.