Parallel determination of NeuroD1, chromogranin-A, KI67 and androgen receptor expression in surgically treated prostate cancers.

PURPOSE: Neuroendocrine differentiation is a hallmark of prostate cancer. The aim of our study was the detection of the parallel expression of neuroendocrine related markers using a prostate tissue microarray (TMA). MATERIALS AND METHODS: Our study was aimed at detecting the parallel expression of NeuroD1, Chromogranin-A (ChrA), Androgen Receptor (AR) and Ki-67 by immunohistochemistry on prostate cancer tissue microarray. The data was analyzed using SAS version 8.2 (SAS Inc, Cary, NC). The relationships between NeuroD1, ChrA and AR expressions and patients' characteristics were investigated by multivariate logistic regression analysis. Progression and Overall Survival (OS) distributions were calculated using Kaplan-Meier method. RESULTS: Tissue reactivity for NeuroD1, ChrA and AR concerned 73%, 49% and 77% of the available cases, respectively. Regarding overall survival, there were 87 deaths and 295 patients alive/censored (6 years of median follow-up). Seventy-seven disease progressions occurred at the median follow-up 5.4y. A significant correlation between NeuroD1, ChrA and AR expression was observed (p < 0.001 and p < 0.03, respectively). Additionally, ChrA was strongly associated in multivariate analysis to Gleason score and Ki67 expression (p < 0.009 and p < 0.0052, respectively). Survival analysis showed no association between markers neither for overall nor for cancer-specific survival. CONCLUSIONS: The results highlight that NeuroD1, Chromogranin-A and Androgen Receptor are strongly associated, however their expression does not correlate with overall survival or disease progression.

Homeobox genes in normal and abnormal vasculogenesis.

Homeobox containing genes are a family of transcription factors regulating normal development and controlling primary cellular processes (cell identity, cell division and differentiation) recently enriched by the discovery of their interaction with miRNAs and ncRNAs. Class I human homeobox genes (HOX genes) are characterized by a unique genomic network organization: four compact chromosomal loci where 39 sequence corresponding genes can be aligned with each other in 13 antero-posterior paralogous groups. The cardiovascular system is the first mesoderm organ-system to be generated during embryonic development; subsequently it generates the blood and lymphatic vascular systems. Cardiovascular remodelling is involved through homeobox gene regulation and deregulation in adult physiology (menstrual cycle and wound healing) and pathology (atherosclerosis, arterial restenosis, tumour angiogenesis and lymphangiogenesis). Understanding the role played by homeobox genes in endothelial and smooth muscle cell phenotype determination will be crucial in identifying the molecular processes involved in vascular cell differentiation, as well as to support future therapeutic strategies. We report here on the current knowledge of the role played by homeobox genes in normal and abnormal vasculogenesis and postulate a common molecular mechanism accounting for the involvement of homeobox genes in the regulation of the nuclear export of specific transcripts potentially capable of generating endothelial phenotype modification involved in new vessel formation.

Generation of drug-resistant variants in metastatic B16 mouse melanoma cell lines.

Genetic instability is recognized as an important aspect of the development of tumor heterogeneity and malignancy. In a previous study [Hill et al. Science (Wash. DC), 244:998-1001, 1984], we demonstrated that metastatic variants are generated at a more rapid rate in the highly metastatic B16F10 mouse melanoma cell line than in the less metastatic B16F1 cell line. The metastatic variants were phenotypically unstable, being generated and lost at high rates; consequently, we proposed a dynamic heterogeneity model of tumor metastasis which describes these properties quantitatively. As an extension of this work, we have examined the ability of these two melanoma cell lines to generate variants resistant to the drugs methotrexate and N-(phosphonacetyl)-L-aspartate. We observed that the highly metastatic B16F10 cell line generated variants resistant to a given concentration of methotrexate or N-(phosphonacetyl)-L-aspartate at higher rates than the B16F1 cell line. We conclude that B16F10 cells are genetically less stable than B16F1 cells and since resistance to methotrexate and N-(phosphonacetyl)-L-asparate usually results from gene amplification that B16F10 cells possess increased ability to amplify DNA. This higher rate of generation of drug-resistant variants corresponds to the higher rate of generation of metastatic variants we observed previously and suggests that a gene amplification mechanism may be involved in the generation of a metastic phenotype in B16 melanoma cells.

Fluctuations of BFUe and CFUe cycling after erytrhoid perturbations: correlation with variations of pool size.

The pool size of erythroid burst-(BFUe) and colony-forming units (CFUe) has been evaluated in normal or hypoxia-induced polycythemic mice at sequential times after either transfusion or administration of purified erythropoietin (Ep). The present investigations were focused on the in vitro tritiated thymidine (3H-TdR) suicide index of the erythroid precursors in these two experimental models. After transfusion an early but transient decline of the DNA sythesis index was observed in the BFUe pool, whereas this parameter showed a later, more prolonged decrease within the CFUe population. Symmetric patterns were documented after Ep injection: an early, transient elevation of the 3H-TdR sensitivity at the BFUe level and a late, more persistent rise within the CFUe compartment. In all experiments no modification of this indes was observed within the pool of the CFUe. These fluctuations of BFUe and CFUe cycling were temporally consistent with modifications of their respective pool size, as previously reported. Thus, variations of the pool size may be at least partially mediated by the cycling activity. Furthermore, early fluctuations of BFUe proliferative rate indicate that, after erythroid perturbations, this pool may initially be sensitive to and regulated by modifications of Ep activity. Later, however, compensatory mechanisms allow the BFUe to escape from this early Ep influence, thus leading its cycling activity and pool size to return to normality and stabilize.

Early fluctuations of BFU-E pool size after transfusion or erythropoietin treatment.

The kinetics of erythroid burst-(BFU-E) and colony-forming units (CFU-E) have been evaluated in marrow and spleen of normal or polycythemic mice, respectively, after transfusion or administration or purified erythropoietin (Ep). Ep injection induces an early but temporary rise of BFU-E number, versus a later but more prolonged expansion of the CFU-E pool. Symmetric patterns are observed after transfusion, i.e., an early but transient depletion of the BFU-E population, versus a later but more persistent decrease of the CFU-E number. It is suggested that the size of the BFU-E compartment is Ep-dependent in the "early" phase after erythroid perturbation. Later on, however, compensatory mechanisms allow the BFU-E pool to "escape" from the early Ep influence, thus allowing its size to return to and stabilize in the near normal range. It is further suggested that the BFU-E may represent an early target cell of Ep stimulus.

Relationship between DNA methylation and gene expression of the HOXB gene cluster in small cell lung cancers.

The expression pattern of the HOXB gene cluster in four xenografted small-cell lung cancers was compared to the methylation of the DNA in the corresponding genomic regions. In 90% (17/19) of the studied cases, the expressed genes were in methylated regions whereas 70% (12/17) of the unexpressed genes were in unmethylated regions. This specific behavior could correspond to a particular gene expression regulation mechanism of the HOX gene network. Since some genes (HOXB2, HOXB4, HOXB7) were always inactive when unmethylated, this unexpected relationship might indicate their key function(s) in the HOX gene network.

In vivo expression of the whole HOX gene network in human breast cancer.

The HOX network contains 39 genes that act as transcriptional regulators and control crucial cellular functions during both embryonic development and adult life. Inside the network, this is achieved according to the rules of temporal and spatial co-linearity with 3' HOX genes acting on the anterior part of the body, central HOX genes on the thoracic part and lumbo-sacral HOX genes on the caudal region. We analysed HOX gene expression in normal breast tissue and in primary breast cancers by reverse-transcriptase-polymerase chain reaction (RT-PCR). 17 out of 39 HOX genes were expressed in the normal breast tissue. The expression of thoracic HOX genes tended to be similar in normal and neoplastic breast tissues suggesting that these genes are involved in breast organogenesis. In contrast, cervical and lumbo-sacral HOX gene expression was altered in the primary breast cancers with respect to normal breast tissue. This supports their involvement in breast cancer evolution and suggests they could be targets for future cancer therapies.

Expression of homeobox-containing genes in primary and metastatic colorectal cancer.

Homeobox genes are a network of genes encoding nuclear proteins functioning as transcriptional regulators. Human and murine homeobox genes of the HOX family are organised in four clusters on different chromosomes. Gene order within each cluster is highly conserved, perhaps in direct relation to their expression. Homeobox genes have recently been involved in normal development and oncogenesis. We have analysed HOX gene expression in normal human colon and in primary and metastatic colorectal carcinomas. The majority of HOX genes are active in normal adult colon and their overall expression pattern is characteristic of this organ. Furthermore, the expression of some HOX genes is identical in normal and neoplastic colon indicating that these genes may exert an organ-specific function. In contrast, other HOX genes exhibit altered expression in primary colon cancers and their hepatic metastases which may suggest an association with colon cancer progression.

Expression and structure of hox genes in wilms-tumor.

We have investigated the expression of all 38 human HOX genes in Wilms' tumour (WT) tissue, and the structure of the HOXA cluster (at chromosome 7p15) in a WT patient who has a novel constitutional chromosome translocation (t(1;7)(q42;p15)). No rearrangement of the HOXA genes was found in the translocation patient, but between 26 and 28 HOX genes were expressed in WT tissue. Thus, although it appears unlikely that HOX genes are mutated in WT, their extensive expression in WT indicates that HOX genes may well be important factors in the aberrant differentiation which leads to Wilms' tumour.

Early hemopoietic progenitor cells: direct measurement of cell cycle status.

We have investigated the cell cycle status of murine hemopoietic progenitors using vital DNA staining and flow sorting. Suspended Balb/c bone marrow cells were stained with Hoechst 33342 dye and separated first on light scattering properties; this procedure allowed a 5-fold enrichment in progenitor cells. A second sorting based on DNA content indicated that 80% of these cells were in G0/G1 and 20% in S-G2 + M. When G0/G1 and S-G2 + M cells were assayed separately in methylcellulose cultures, or with the in vivo colony forming assay, the G0/G1 cells were shown to be markedly enriched in CFU-S, BFU-E, and GM-CFU as compared to S-G2 + M cells with the final recovery increased 20-fold. Comparison of different strains or age groups yielded results identical to those obtained with Balb/c with the exception of C57B1/6. In the latter strain only a 3-fold enrichment could be observed in the G0/G1 fraction. These results demonstrate that the majority of early hemopoietic progenitors are in the G0/G1 phase of the cell cycle.

[Apropos of the studies of Lewis, Nusslein-Volhard and Wieschaus, 1995 Nobel prize winners, on the genetic mechanisms of embryonic development of drosophila. A model for human cancer progression]. / A propos des travaux de Lewis, Nusslein-Volhard et Wieschaus, prix Nobel de médecine 1995, sur la génétique du développement embryonnaire de la drosophile. Un modèle pour aborder la progression des cancers humains.

EB Lewis, C Nusslein-Volhard and E Wieschaus were the winners of the Nobel prize in 1995 for the discovery of genes controling the embryonic development in drosophila. Drosophila development is dependent on sequential activities of three types of genes: the maternal genes, the segmentation genes, and the homeotic genes which are responsible for the segment identity and finally for the building of the body. Mutations of these genes are spectacular because they affect the body structure formed from individual segments. Therefore, the molecular processes regulating the development of inferior organisms such as yeast or more complex as the vertebrates were elucidated by these three researchers. These early biological mechanisms regulate the cell life through interactions with neighbouring cells. We speculate that any alteration of these processes might be implicated in cancer. Understanding of these molecular mechanisms which control cell interactions in cancer constitutes a basis for definition of new prognostic markers and putatively novel therapeutic approaches.

[The cellular and molecular bases of "tooth framing"]. / Le basi cellulari e molecolari della "costruzione" dei denti.

Progress in molecular biology in recent years has enormously increased interest in tooth generation. The enamel knot has been discovered, in consequence. This is a transient structure acting as molecular signaling center, responsible for controlling cusp formation, stimulating growth of surrounding epithelium, and generating new knots or their disappearance through apoptosis. Both tooth development and enamel knots are regulated by a cascade of gene activity where Fgf4, Shh, BMP4, Lef1 and p21 are the prime movers of the processes. Homeobox genes (Msx, Dlx) are the orchestrators of the framing and a series of proteins (adhesion molecules, extracellular matrix components) are the executors of "tooth framing". An important concept has emerged from developmental biology through the identification of the basic mechanisms involved in tooth development: the molecular basis of structure framing shares common rules. Thus similar genetic programs are involved in body structure generation (limb bud, tooth, branching morphogenesis). A deeper understanding of developmental rules regulating tooth formation will make it possible in the near future: a) to modify in vivo homeobox gene expression and restore tooth generation hampered by tooth agenesia due to homeobox gene deregulation; b) to induce complete tooth formation, in case of tooth loss due to trauma or diseases, through implantation in the patient's oral cavity of a synthetic ball containing morphogens and growth factors to stimulate, in the right spatio-temporal sequence, the entire tooth genetic cascade. These concepts will certainly enforce cultural and practical interaction between biology and dentistry.

Deregulation of HOX B13 expression in urinary bladder cancer progression.

Urinary bladder cancer is a common malignancy in industrialized countries. More than 90% of bladder cancer originates in the transitional cells. Bladder transitional cancer prognosis is, according to the most recent definition related to the level of tumor infiltration, characterized by two main phenotypes, Non Muscle Invasive Bladder Transitional Cancer (NMIBC) and Muscle Invasive Bladder Transitional Cancer (MIBC). The genetic profile and the clinical course of the two subtypes are completely different, however among NMIBC the prognosis is not completely predictable, since 20% of the cases experience a relapse, even in the form of MIBC. It has recently been reported that the chromosomal region 12q13-15, containing crucial cancer genes such as MDM2, CDK4, GLI and an entire cluster of HOX genes, is amplified in bladder cancer. HOX genes codify for transcriptionl factor, involved in embryonal development and cancer progression, with main nuclear expression. Particularly it was also described the strong involvement of HOX B13 in several tumors of urogenital system. In this study we have been investigated, by immunohistochemisty and quantitative Real Time PCR, the HOX B13 expression in bladder cancer evolution and progression, evaluating its ability to discriminate between NMIBC and MBCI phenotypes. Cytoplasmic HOX B13 delocalization significantly relates with muscle invasion (p 0.004). In addition in the series of NMIBC nuclear HOX B13 expression loss is significantly associated to shorter disease free survival (p-value=0.038) defining a potential prognostic role. Overexpression of HOX B13 in more aggressive phenotype is also demonstrate at gene level by quantitative RT-PCR. The de-regulation and delocalization of HOX B13 in urinary bladder cancer supports again the important role of HOX genes in tumor evolution and represents a starting point to establish an integrated analysis, in which HOX genes represent important prognostic and predictive markers for bladder cancer.

The HOX genes network in uro-genital cancers: mechanisms and potential therapeutic implications.

Genito-urinary malignancies (prostate, bladder, renal and testicular cancers) rank high among human tumors with an incidence that varies with age and organ involvement. Prostate cancer is the most commonly detected male cancer followed by bladder and kidney cancers, less frequent in women. Testicular cancer, although rare, is the most frequent cancer in males under 35. The majority of oncogenic and tumor suppressor signaling pathways involved with urogenital cancers converge on sets of transcription factors that ultimately control gene expression resulting in tumor formation and metastatic progression. The activity of these transcription factors is modulated by multiple mechanisms spanning from transcriptional regulation, deregulation of the splicing, maturation, export and location of mRNAs, protein synthesis and post-translational modifications. The recent involvement of the epigenitic mechanisms in the generation and the evolution of cancer has produced a great deal of interest. This is related to the possibility that revealing these mechanisms able to regulate the cell memory program (the gene systems polycomb, trithorax and HOX) may generate important biological and therapeutic achievements. The HOX gene network is the only physically and functionally identifiable transcription factor network located in the human genome controlling crucial cellular processes. Here we describe the implication of the HOX genes in the urogenital embryonic development and cancers. We further highlight the mechanisms uncovered along these processes and involving the HOX genes. Finally, we foresee the specific targeting of HOX genes and in general the cell memory gene program in the therapeutic setting of urogenital malignancies due to their upstream location in these stepwise cell processes and their early deregulation in cancer evolution.