The assessment of cellular proliferation by immunohistochemistry: a review of currently available methods and their applications

Four cardiac hormones eliminate up to 82% of human medullary thyroid carcinoma cells within 24 hours

Four cardiac hormones, i.e., atrial natriuretic peptide, vessel dilator, long-acting natriuretic peptide, and kaliuretic peptide, which have anticancer effects, were evaluated for the first time on any endocrine cancer to determine if they have anticancer effects in an endocrine cancer. These four cardiac hormones were evaluated for their anticancer, DNA synthesis, and receptor status in human medullary thyroid cancer cells. There was a significant (p < 0.001) decrease in human medullary thyroid cancer cells with each 10-fold increase from 1 to 100 microM of the four cardiac hormones. There was an 81%, 68%, 71%, and 66% elimination within 24 h of medullary thyroid cancer cells secondary to vessel dilator, kaliuretic peptide, atrial natriuretic peptide, and long-acting natriuretic peptide, respectively (p < 0.0001). Three days after treatment with these peptide hormones, there was no proliferation of the medullary thyroid cancer cells. These cardiac hormones decreased DNA synthesis in the medullary thyroid cells from 65% to 84% (p < 0.0001). Western blots revealed natriuretic peptide receptors-A and -C were present in human medullary thyroid cancer cells. These results indicate the four cardiac hormones have potent anticancer effects by eliminating up to 82% of human medullary thyroid carcinoma cells within 24 h of treatment.

Urodilatin and four cardiac hormones decrease human renal carcinoma cell numbers

BACKGROUND

Mortality from renal-cell cancer remains a significant problem with an estimated 12,600 deaths in the United States in 2005 even with current treatment(s) of surgery, chemotherapy, radiation and immunotherapy. Four cardiac natriuretic peptides, that is, atrial natriuretic peptide, vessel dilator, long-acting natriuretic peptide and kaliuretic peptide have significant anti-cancer effects in breast, pancreatic, prostate and colon adenocarcinomas.

MATERIALS AND METHODS

These four peptide hormones plus brain natriuretic peptide (BNP), C-natriuretic peptide (CNP) and urodilatin, a peptide hormone formed in the kidney by a different post-translational processing of the atrial natriuretic peptide prohormone, were evaluated for their anti-cancer effects in renal carcinomas.

RESULTS

Dose-response curves revealed a significant (P < 0.0001) decrease in human renal carcinoma cells with each 10-fold increase in concentration from 1 microm to 100 microm of five of these peptide hormones. There was an 81%, 74%, 66%, 70% and 70% elimination within 24 h in renal carcinoma cells secondary to vessel dilator, kaliuretic peptide, urodilatin, atrial natriuretic peptide and long-acting natriuretic peptide, respectively (P < 0.0001 for each), whereas BNP had no effect and CNP decreased renal cancer cell number by 10% (P = 0.04) at their 100 microm concentrations. Three days after treatment with these peptide hormones, the cancer cells began to proliferate again. The four cardiac hormones and urodilatin decreased DNA synthesis from 65-84% (P < 0.00001), whereas BNP and CNP decreased DNA synthesis 3% and 12% (both non-significant). Western blots revealed for the first time natriuretic peptide receptors (NPR)-A, -B and -C were present in the renal cancer cells.

CONCLUSIONS

These results indicate that urodilatin and the four cardiac hormones have potent anti-cancer effects by eliminating up to 81% of renal carcinoma cells within 24 h of treatment.

p16INK4A is a robust in vivo biomarker of cellular aging in human skin

The cell-cycle regulating gene, p16INK4A, encoding an inhibitor of cyclin-dependent kinases 4 and 6, is considered to play an important role in cellular aging and in premature senescence. Although there is an age-dependent increase of p16INK4A expression in human fibroblast senescence in vitro, no data are available regarding the age dependency of p16INK4A in vivo. To determine whether p16INK4A expression in human skin correlates with donor age, p16INK4A expression was analyzed by immunohistochemistry as well as the expression of the p16INK4A repressor BMI1. Samples from the age groups 0-20, 21-70, and 71-95 years were selected from a bank of healthy human skin. We show that the number of p16INK4A positive cells is significantly higher in elderly individuals compared to the younger age groups. The number of p16INK4A positive cells was found to be increased in both epidermis and dermis, compartments with strictly different proliferative activities. BMI1 gene expression was significantly down-regulated with increasing donor age, whereas no striking age differences were observed for Ki67. In immunofluorescence co-expression studies, Ki67-positive cells were negative for p16INK4A and BMI1-expressing cells also stained negatively for Ki67. In conclusion, we provide for the first time evidence that p16INK4A expression directly correlates with chronological aging of human skin in vivo. p16INK4A therefore is a biomarker for human aging in vivo. The data reported here suggest a model for changes in regulatory gene expression that drive aging in human skin.

An ELISA-based method for the quantification of incorporated BrdU as a measure of cell proliferation in vivo

In this study, we describe a new rapid and versatile method to determine the BrdU content of DNA in brain tissues dissected from BrdU-treated rats. Different to already existing BrdU ELISAs the method is suitable for the assessment of BrdU incorporation in ex vivo experiments as it is based on the analysis of tissue extracts instead of immobilized cells. The method comprises the preparation of DNA extracts from dissected tissues, the immobilization of BrdU-containing DNA with an anti-BrdU antibody and quantification of the incorporated BrdU by a peroxidase-conjugated anti-BrdU antibody. Validating the new assay in vitro, we found a clear-cut dependency of the ELISA signal from the time SKNSH neuroblastoma cells had been exposed to BrdU. Parallel studies with existing ELISAs and a parallel immunocytochemical determination of BrdU positive cells revealed comparable results. In vivo experiments showed a virtually linear relationship between the BrdU immunoreactivity in the hippocampus and the time rats have been exposed to BrdU. Repeating the determination of the BrdU content of the same set of tissue samples revealed reproducible relative differences of the ELISA signals. This was true for protocols using purified DNA as well as crude DNA extracts. For the sensitivity and reproducibility of the method heat denaturation of the DNA prior to the analysis in the ELISA was crucial. In rats treated with electroconvulsion the BrdU content of the hippocampus, determined by the new ELISA, was increased to 225% of controls. In a parallel immunohistochemical study, the number of BrdU positive cells was comparably increased to 251% of controls. The assay thus provides a rapid method to detect changes of cell proliferation in dissected brain tissues and other proliferative tissues. With appropriate protocols, the assay may also be used to assess the generation of particular cell types like neurons in neurogenic areas.

Analysis of cell proliferation and cell death during in situ hyperthermic treatment of neoplastic cells: a case report of human non-Hodgkin lymphoma

In this study we observed the effects in vivo of hyperthermic treatment on the cell kinetics (cell proliferation/cell death) in one case of human non-Hodgkin lymphoma, by analyzing the following morpho-cytochemical parameters: Acridine Orange fluorochromasia, mitotic index, proliferating cell nuclear antigen (PCNA) expression, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) labeling, and ultrastructure morphology. After two hyperthermic exposures there was a significant reduction of cell growth rate (e.g. mitotic and PCNA positive cells) and an increase in cell loss by death. The cell death occurred by the typical apoptotic cascade, namely DNA fragmentation, chromatin hypercondensation and margination, karyorrhexis, ribonucleoproteins segregation and cytoplasm cleavage; in addition some necrotic cells were found. The data indicates that the hyperthermic treatments limit the cell proliferation (e.g. arrest and/or deceleration of the cell cycle) by facilitating the trigger of programmed cell death. It was concluded that thermal injury can be considered an effective inducer of antiproliferative and apoptogenic associated effects on the growth of this kind of neoplasia.

Ossification of the mouse metatarsal: differentiation and proliferation in the presence/absence of a defined growth plate

There is significant diversity in growth plate behavior among sites within an individual skeleton and between skeletons of different species. This variation within wild-type animals is an underutilized resource for studying skeletal development. One bone that potentially exhibits the most diverse behavior is the metatarsal. While one end forms a growth plate with an epiphyseal secondary center of ossification as in other long bones, the opposite end undergoes direct ossification in a manner more similar to short bones. Although descriptions of human metatarsal/metacarpal ossification are available, a detailed comparative analysis has yet to be conducted in an animal model amenable to biomolecular analysis. Here we report an analysis of proximal and distal ossification in an age series of mouse metatarsals. Safranin O staining was used for qualitative and quantitative histology, and chondrocyte differentiation and proliferation were analyzed using immunohistochemistry for type X collagen and proliferative cell nuclear antigen expression. We establish that, as in the human, both growth plate formation and direct ossification occur in the mouse metatarsal, with chondrocyte populations showing distinct differentiation patterns at opposite ends of the bone. In addition, growth plate formation is characterized by a peak of proliferation in reserve zone chondrocytes that distinguishes it from both established growth plates and direct ossification. Our analysis demonstrates that the mouse metatarsal is a productive model for investigating natural variation in ossification that can further understanding of vertebrate skeletal development and evolution.

Skin lesion development in a mouse model of incontinentia pigmenti is triggered by NEMO deficiency in epidermal keratinocytes and requires TNF signaling

NF-kappaB essential modulator (NEMO), the regulatory subunit of the IkappaB kinase, is essential for NF-kappaB activation. Mutations disrupting the X-linked NEMO gene cause incontinentia pigmenti (IP), a human genetic disease characterized by male embryonic lethality and by a complex pathology affecting primarily the skin in heterozygous females. The cellular and molecular mechanisms leading to skin lesion pathogenesis in IP patients remain elusive. Here we used epidermis-specific deletion of NEMO in mice to investigate the mechanisms causing the skin pathology in IP. NEMO deletion completely inhibited NF-kappaB activation and sensitized keratinocytes to tumor necrosis factor (TNF)-induced death but did not affect epidermal development. Keratinocyte-restricted NEMO deletion, either constitutive or induced in adult skin, caused inflammatory skin lesions, identifying the NEMO-deficient keratinocyte as the initiating cell type that triggers the skin pathology in IP. Furthermore, genetic ablation of tumor necrosis factor receptor 1 (TNFRI) rescued the skin phenotype demonstrating that TNF signaling is essential for skin lesion pathogenesis in IP. These results identify the NEMO-deficient keratinocyte as a potent initiator of skin inflammation and provide novel insights into the mechanism leading to the pathogenesis of IP.

Pregnancy effects on distribution of progesterone receptors, oestrogen receptor α, glucocorticoid receptors, Ki-67 antigen and apoptosis in the bovine interplacentomal uterine wall and foetal membranes

Until recently, studies dealing with the uterus of the pregnant cow focus primarily on the placentome or on early and late pregnancy. Thus, there is a paucity of information about many aspects of the interplacentomal uterine wall including adherent foetal membranes. Corresponding tissue specimens were collected at the slaughterhouse and in animals undergoing premature caesarean section. Two specimens per month of pregnancy were assessed immunohistochemically for progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, Ki-67 protein and TUNEL procedure was performed. The latter two methods were employed in three animals each per months 1 and 2, 3 and 4, 7 and 8 and in six animals undergoing caesarean section at days 274 and 275 post insemination or during spontaneous labour. Results indicate that proliferation and apoptosis are of minor importance for tissue homeostasis since both can histochemically be detected only sporadically. Thus, at the sites investigated here, cellular hypertrophy plays an important role for tissue growth during pregnancy. Progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, however, exhibit cell type and pregnancy stage specific distribution patterns within the tissues assessed. Progesterone receptor immunoreactive scores remained fairly unchanged during pregnancy. Oestrogen receptor alpha scores, however, generally decreased and glucocorticoid receptors increased with ongoing gestation. Progesterone receptors and oestrogen receptor alpha were present in endometrial stroma and in myometrial smooth muscle cells during whole pregnancy. Oestrogen receptor alpha was detectable during whole pregnancy also in uterine glands. Progesterone receptors were, however, present at a very low level at the latter site only during months 1-3 and 6-9. Oestrogen receptor alpha and glucocorticoid receptors may also mediate uterine blood flow since they were present in the tunica media of uterine blood vessels. Results of the present study indicate, that progesterone and its receptor play an important role during whole gestation, mainly for uterine quiescence. Glucocorticoids and their receptors - possibly in cooperation with oestrogens and decreasing amounts of the oestrogen receptor alpha - should trigger processes initiating parturition, such as endometrial prostaglandin production. Further studies - including the periparturient period - should help to understand the exact role of the extraplacental compartment of the uterine wall for the initiation and progress of parturition.

Effects of maternal undernutrition during early pregnancy on apoptosis regulators in the ovine fetal ovary

This study aimed to determine whether reduced fetal ovary folliculogenesis in ewes undernourished during early/midpregnancy is associated with altered ovarian cell proliferation and/or the expression of apoptosis-regulating genes. Groups of ewes (n= 11–19) were fed either 100% (high; H) or 50% (low; L) of metabolisable energy requirements for live-weight maintenance during selected windows of gestation. All animals were killed at days 50, 65 or 110 of gestation. Between mating and slaughter, control animals were fed the H ration, while animals of other subgroups were fed the L ration from (a) mating to slaughter at 50, 65 or 110 days; (b) 0 to 30 days; (c) 31 to 50 or 65 days; or (d), in the day 110 slaughter group only, from 66 to 110 days. Bouin’s-fixed fetal ovaries were examined for (a) Ki67 immunoexpression (proliferation) and (b) Bax and Mcl-1 (apoptosis-regulating genes) expression byin situhybridisation (day 110) and immunohistochemistry (days 50, 65 and 110). At day 50, maternal nutrition had no effect on Ki67, predominant in germ cells, or Bax and Mcl-1, predominant in the oocytes. Restricted maternal food intake from 0 to 30 days significantly reduced staining for Ki67 in germ cells at day 65 (P< 0.05) but increased staining in granulosa cells at day 110 (P< 0.05). In animals fed the L ration for 110 days, primordial follicle Bax and Mcl-1 were significantly increased (Bax:P< 0.01; Mcl-1:P< 0.05). Granulosa cell Bax was also increased (P< 0.05). When the L ration was fed from 66 to 110 days, granulosa cell Bax (P< 0.05) and primordial follicle Mcl-1 (P< 0.01) were also significantly increased. In the fetal ovarian vasculature, animals underfed for 0–110 days had significantly elevated perivascular Mcl-1 (P< 0.001) and endothelial Bax expression (P< 0.05). Moreover, at day 110, endothelial Mcl-1 was increased by underfeeding from 0 to 30 days (P< 0.05). These data indicate that maternal undernutrition alters proliferation and the expression of apoptosis-regulating genes in the developing fetal ovary. The precise mechanism depends on the window of maternal food restriction.

Electrophysiological Properties of Pluripotent Human and Mouse Embryonic Stem Cells

Pluripotent embryonic stem cells (ESCs) possess promising potential for cell-based therapies, but their electrophysiological properties have not been characterized. Here we describe the presence of ionic currents in mouse (m) and human (h) ESCs and their physiological function. In mESCs, tetraethylammonium (TEA)-sensitive depolarization-activated delayed rectifier K+ currents (IK(DR)) (8.6 +/- 0.9 pA/pF at +40 mV; IC50 = 1.2 +/- 0.3 mM), which contained components sensitive to 4-aminopyridine (4-AP) (IC50 = 0.5 +/- 0.1 mM) and 100 nM Ca2+-activated K+ current (IK(Ca)) blocker iberiotoxin (IBTX),were detected in 52.3% of undifferentiated cells.IK(DR) was similarly present in hESCs (approximately 100%) but with an approximately sixfold higher current density (47.5 +/- 7.9 pA/pF at +40 mV). When assayed by bromodeoxyurindine incorporation, application of TEA, 4-AP, or IBTX significantly reduced the proliferation of mESCs and hESCs in a dose-dependent manner (p < .05). A hyperpolarization-activated inward current (I(h)) (-2.2 +/- 0.4 pA/pF at -120 mV) was detected in 23% of mESCs but not hESCs. Neither Na(v) nor Ca(v) currents were detected in mESCs and hESCs. Microarray and reverse transcription-polymerase chain reaction analyses identified several candidate genes for the ionic currents discovered. Collectively, our results indicate that pluripotent ESCs functionally express several specialized ion channels and further highlight similarities and differences between the two species. Practical considerations for the therapeutic use of ESCs are discussed.

Four peptide hormones' specific decrease (up to 97%) of human prostate carcinoma cells

BACKGROUND

Mortality from prostate cancer remains a significant problem with current treatment(s), with an expected 30 350 deaths from prostate cancer in 2005. Long-acting natriuretic peptide, vessel dilator, kaliuretic peptide and atrial natriuretic peptide have significant anticancer effects in breast and pancreatic adenocarcinomas. Whether these effects are specific and whether they have anticancer effects in prostate adenocarcinoma cells has not been determined.

MATERIALS AND METHODS

These peptide hormones were evaluated to determine if they have specific anticancer effects in human prostate adenocarcinomas.

RESULTS

Dose-response curves revealed a significant (P < 0.05) decrease in human prostate cancer number with each tenfold increase in the concentration from 1 microM to 1000 microM (i.e. 1 mM) of these four peptide hormones. There was a 97.4%, 87%, 88% and 89% (P < 0.001 for each) decrease in prostate cancer cells secondary to vessel dilator, long-acting natriuretic peptide, kaliuretic peptide and atrial natriuretic peptide, respectively, at their 1-mM concentrations within 24 h, without any proliferation in the 3 days following this decrease. These same hormones decreased DNA synthesis from 68% to 89% (P < 0.001). When utilized with their respective antibodies their ability to decrease prostate adenocarcinoma cells or inhibit their DNA synthesis was completely blocked. Western blots revealed that for the first time natriuretic peptide receptors (NPR) A- and C- were present in prostate cancer cells.

CONCLUSIONS

These results indicate that these peptide hormones' anticancer effects are specific. Furthermore, they have very potent effects of eliminating up to 97% of prostate cancer cells within 24 h of treatment.

Basal-like Cells Constitute the Proliferating Cell Population in Cystic Fibrosis Airways

RATIONALE

Cystic fibrosis airways are recurrently exposed to noxious stimuli, leading to epithelial injury. Previous reports suggest that cystic fibrosis airway epithelia may respond to injury by increasing proliferation.

OBJECTIVES

We sought to determine the characteristics of the proliferating cell population in cystic fibrosis airways.

METHODS

Six cystic fibrosis and six normal lung sections from lung transplant recipients or lung surgery were obtained from the Duke Hospital pathology archives. Sections containing bronchi were evaluated for epithelial cell proliferation using immunohistochemistry for a nuclear proliferation antigen, Ki-67, and image analysis; immunohistochemistry for basal cells using a cytokeratin 5/14 antibody; and immunohistochemistry for the epidermal growth factor receptor and ErbB2, two receptor tyrosine kinases implicated in epithelial proliferation and differentiation.

RESULTS

Overall, cystic fibrosis sections had a greater proliferation index than control sections with 25.1 +/- 2.1% positively staining nuclei/total nuclei compared with control sections, 4.6 +/- 0.9% (p = 0.002). In cystic fibrosis sections only, there were areas of hyperplastic cuboidal cells adjacent to normal pseudostratified columnar epithelial sections; in these areas of epithelial hyperplasia, there was uniform Ki-67 staining, indicating a zone of proliferating cells. The proliferating cell population also expressed the basal cell cytokeratins 5/14 and epidermal growth factor receptor. Expression of ErbB2 was diminished in the proliferating cells.

CONCLUSIONS

Our results suggest that basal-like cells, expressing the epidermal growth factor receptor, constitute the proliferating cell population in cystic fibrosis airways.

The tyrosine kinase pyk2 promotes migration and invasion of glioma cells

Glioblastoma multiforme is extraordinarily aggressive due to the propensity of cells to migrate away from the tumor core into the surrounding normal brain. In this report, we investigated the role of proline-rich tyrosine kinase 2 (Pyk2) and FAK with regard to influencing glioma cell phenotypes. Expression of Pyk2 stimulated glioma cell migration, whereas expression of FAK inhibited glioma cell migration and stimulated cell cycle progression. Pyk2 autophosphorylation was necessary, but not sufficient, to stimulate cellular migration. The N-terminal domain of Pyk2 is required for stimulation of migration as an N-terminally deleted variant of Pyk2 failed to stimulate migration, whereas expression of an autonomous Pyk2 N-terminal domain inhibited cell migration. Substitution of the C-terminal domain of Pyk2 with the corresponding domain of FAK stimulated cell migration as effectively as wild-type Pyk2; however, substitution of the N-terminal domain of Pyk2 with that of FAK inhibited cell migration, substantiating that the N-terminal domain of Pyk2 was required to stimulate migration. Silencing of Pyk2 expression by RNA interference significantly inhibited glioma migration. Cell migration was restored on re-expression of Pyk2, but expression of FAK in Pyk2 knockdown cells failed to restore migration. We conclude that Pyk2 plays a central role in the migratory behavior of glioblastomas.

Apoptosis and cell proliferation in proliferative retinal disorders: PCNA, Ki-67, caspase-3, and PARP expression

PURPOSE

To assess the incidence of cell proliferation and apoptosis in epiretinal membranes from eyes with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), and macular pucker (MP) and to further investigate the potential involvement of key executors of apoptosis.

METHODS

Epiretinal membranes were obtained from the eyes of 23 patients who underwent vitrectomy surgery for recurrent retinal detachment due to PVR (n = 16), traction retinal detachment due to PDR (n = 5), and macular pucker (n = 2). Cell proliferation was evaluated by Ki-67 and PCNA (proliferation cell nuclear antigen) immunostaining. Apoptosis was assessed by TUNEL (terminal deoxynucleotidyl transfrase-dUTP-nick end labeling). The expression of caspase-3 and PARP (poly-ADP-ribose-polymerase) was detected using antibodies against activated caspase-3 and p85 fragment of PARP. Cytokeratin and activated caspase-3/PARP, GFAP (glial fibrillary acidic protein) and activated caspase-3/PARP double staining were used to identify cell types in the membranes.

RESULTS

There was no statistically significant difference in the cell proliferative index between PVR (70.1 +/- 4.2%), PDR (82.1 +/- 7.0%), and macular pucker (72.9 +/- 22.8%) by multivariate analysis (p = 0.39, ANOVA) and univariate analysis. Apoptotic nuclei were seen more frequently in chronic retinal detachments of greater than 2 months duration, but the difference, compared to shorter term retinal detachments was not statistically significant (p = 0.19). The apoptosis indices determined for PVR (2.3 +/- 0.7%), PDR (3.4 +/- 1.5%) and macular pucker (5.5 +/- 3.2%) were not significantly different (ANOVA, p = 0.41). Apoptotic nuclei were correlated, increased with expression of caspase-3 and PARP. Many apoptotic cells appeared to derive from retinal pigment epithelium cells.

CONCLUSIONS

Cell proliferation and apoptosis appear to be key mechanisms regulating certain cell populations in epiretinal membranes of PVR, PDR, and macular pucker. Inhibition of proliferative regulators such as PCNA and/or activation of apoptotic executors such as caspase-3 may serve as therapeutic targets to halt progression of proliferative retinal disorders.

Foxl2 is required for commitment to ovary differentiation

Genetic control of female sex differentiation from a bipotential gonad in mammals is poorly understood. We find that mouse XX gonads lacking the forkhead transcription factor Foxl2 form meiotic prophase oocytes, but then activate the genetic program for somatic testis determination. Pivotal Foxl2 action thus represses the male gene pathway at several stages of female gonadal differentiation. This suggests the possible continued involvement of sex-determining genes in maintaining ovarian function throughout female reproductive life.

Five cardiac hormones decrease the number of human small-cell lung cancer cells

BACKGROUND

Four peptide hormones of a family of six hormones, i.e. atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-natriuretic peptide (CNP), long acting natriuretic peptide (LANP), vessel dilator and kaliuretic peptide, significantly decrease the number of adenocarcinoma cells in culture. The present investigation was designed to determine whether these peptide hormones' effects are specific to adenocarcinomas or whether they might decrease the number of cancer cells of a different type of cancer, i.e. small-cell lung cancer.

METHODS AND MATERIALS

These six hormones were evaluated for their ability to decrease the number and/or proliferation of human small-cell lung cancer cells in culture for 24, 48, 72, and 96 h.

RESULTS

Within 24 h, vessel dilator, LANP, kaliuretic peptide, ANP and their intracellular mediator cyclic GMP, each at 1 microM, decreased the number of small-cell lung cancer cells by 63% (P < 0.001), 21% (P < 0.05), 30% (P < 0.05), 39% (P < 0.05), and 31% (P < 0.05), respectively. There was no proliferation in the 3 days following this decrease in cell number. These same hormones decreased DNA synthesis 68% to 82% (P < 0.001). Brain natriuretic peptide and CNP did not decrease the number of small-cell lung cancer cells or inhibit their DNA synthesis at 1 microM or 10 microM concentrations. Dose-response curves revealed that at 100 microM, the vessel dilator decreased 92% of the cancer cells in 24 h while BNP had no effect, but CNP caused a 39% decrease. Western blots revealed that the natriuretic peptide receptors A- and C- were present in these cancer cells.

CONCLUSIONS

Five peptide hormones significantly decrease the number of human small-cell lung cancer cells within 24 h and inhibit their proliferation for at least 96 h. Their mechanism of doing so involves inhibition of DNA synthesis mediated in part by cyclic GMP.

Cell proliferation in the forebrain and midbrain of the sea lamprey

Cell proliferation in the forebrain and midbrain of the sea lamprey (Petromyzon marinus L.) was investigated by proliferation cell nuclear antigen (PCNA) immunocytochemistry, with BrdU labeling as a complementary technique. Correspondence between proliferation regions and areas of early neuronal differentiation was also assessed using antibodies against HNK-1 early differentiation marker. The brain of late embryos shows a homogeneously thick ventricular zone (VZ) containing PCNA-immunoreactive (PCNA-ir) nuclei. In early prolarvae, several discontinuities formed by PCNA-negative cells, and differences among regions in VZ thickness, become apparent. In late prolarvae and early larvae, these differences in VZ thickness and appearance, as well as the presence of PCNA-negative discontinuities, allowed us to correlate proliferation domains and neuroanatomical regions. In larvae, the number of PCNA-ir cells in the VZs diminish gradually, although a few PCNA-ir cells are present in the ependyma of most regions. In late larvae, proliferation becomes confined to a few ventricular areas (medial pallium, caudal habenula, ventral preoptic recess near the optic nerve, and tuberal portion of the posterior hypothalamic recess). During metamorphosis there appears to be no proliferation, but in upstream adults a few PCNA-ir cells are observed in the most caudal habenula. The characteristics of the proliferative regions revealed in lamprey with PCNA immunocytochemistry show notable differences from those observed in other vertebrates, and these differences may be related to the peculiar life cycle of lampreys.

Four peptide hormones decrease the number of human breast adenocarcinoma cells

BACKGROUND

A family of six hormones, i.e. atrial natriuretic peptide, brain natriuretic peptide, C-natriuretic peptide, long-acting natriuretic peptide, vessel dilator, and kaliuretic peptide's main known biologic properties are sodium and water excreting and blood pressure lowering.

METHODS AND MATERIALS

These six hormones, each at their 1-microm concentrations, were evaluated for their ability to decrease the number and/or proliferation of breast adenocarcinoma cells in culture for 24, 48, 72, and 96 h.

RESULTS

Within 24 h, vessel dilator, long-acting natriuretic peptide, kaliuretic peptide, atrial natriuretic peptide and 8-bromo-cyclic GMP, a cell-permeable analogue of their intracellular mediator cyclic GMP (each at 1 microm), decreased the number of breast adenocarcinoma cells 60%, 31%, 27%, 40%, and 31%, respectively. There was no proliferation in the 3 days following this decrease in breast adenocarcinoma cell number. These same hormones decreased DNA synthesis 69% to 85% (P < 0.001). Brain natriuretic peptide and CNP did not decrease the number of breast adenocarcinoma cells or inhibit their DNA synthesis. Vessel dilator, long-acting natriuretic peptide, kaliuretic peptide and 8-bromo-cyclic GMP (each at 1 microM) decreased the number of cells in the S phase of the cell cycle by 62%, 33%, 50%, and 39%, respectively (all P < 0.05). Natriuretic peptide receptors-A and -C were present in the breast adenocarcinoma cells.

CONCLUSIONS

Four peptide hormones significantly decrease the number of human breast adenocarcinoma cells within 24 h and inhibit the proliferation of these cells for at least 96 h. Their mechanism of doing so involves inhibition of DNA synthesis and a decrease in cells in the S phase of the cell cycle mediated in part by cyclic GMP.

Spatial Composition of Prostate Cancer Spheroids in Mixed and Static Cultures

Aggregation of neoplastic cells produces multicellular spheroids resembling micrometastases. The objective of this study was to investigate the effects of mixing culture medium on the spatial composition of spheroids prepared from well (LNCaP) and poorly (DU 145) differentiated human prostate cancer cells. Spheroids were cultured in a mixed suspension within a high-aspect rotating wall vessel and static liquid-overlay plate. Results from this study demonstrate that mixed cultures consistently manifested differences in morphology and composition between DU 145 and LNCaP spheroids. For example, 40 +/- 12% of DU 145 cells were Ki-67 positive 100 microm from the surface within mixed spheroids versus 0% for LNCaP cells; there was no significant difference in this spatial profile for static cultures. The results suggest that poorly differentiated spheroids may be more likely to experience a change in composition from mixing culture medium than well-differentiated spheroids, due to low tissue density. Immunostaining for P-glycoprotein is representative of this trend; average staining intensity increased 50% for DU 145 spheroids on mixing but was unchanged for LNCaP spheroids. The effects of mixing on spheroid composition were attributed to faster interstitial mass transport. Applications include drug development and delivery, as well as basic research on drug action and resistance.

Ultraviolet B induces hyperproliferation and modification of epidermal differentiation in normal human skin grafted on to nude mice

BACKGROUND

For ethical and technical reasons, the in vivo biological effects of ultraviolet (UV) radiation on skin are difficult to study in human volunteers. The use of human skin grafted on to nude mice may circumvent this difficulty.

OBJECTIVES

To investigate the effects of a single moderate UVB exposure on human skin grafted on to nude mice.

METHODS

Modifications of epidermal differentiation markers and patterns of keratin expression were assessed from 24 h to 14 days after a physiological UVB irradiation characterized by the induction of sunburn cells.

RESULTS

During the first 48 h postexposure, involucrin, loricrin, transglutaminase type I, filaggrin and keratin K2e expression were altered together with the formation of abnormal horny layers. Constitutive keratin K14 was increased while keratin K10 expression was delayed. Newly synthesized keratins K6, K16, K17 and K19 were induced in parallel with an increase in the epidermal proliferation rate. A progressive normalization of both keratinocyte proliferation and differentiation took place during the following days, reaching completion within 2 weeks.

CONCLUSIONS

Exposure of human skin to a UVB dose corresponding to a mild sunburn reaction induces epidermal hyperproliferation and alterations of several constitutive differentiation markers, as well as a drastic modification in the pattern of epidermal keratins. Although these modifications were shown to be progressively reversed in a single exposure model, the data also suggest that subsequent UV exposures occurring during the recovery period may lead to potentially deleterious long-term consequences, such as photoageing and photocarcinogenesis. Grafted human skin appeared to be an attractive and promising model for investigating the biological consequences of UVB radiation in vivo.

Foxl2 disruption causes mouse ovarian failure by pervasive blockage of follicle development

FOXL2 mutations cause gonadal dysgenesis or premature ovarian failure (POF) in women, as well as eyelid/forehead dysmorphology in both sexes (the 'blepharophimosis-ptosis-epicanthus inversus syndrome', BPES). Here we report that mice lacking Foxl2 recapitulate relevant features of human BPES: males and females are small and show distinctive craniofacial morphology with upper eyelids absent. Furthermore, in mice as in humans, sterility is confined to females. Features of Foxl2 null animals point toward a new mechanism of POF, with all major somatic cell lineages failing to develop around growing oocytes from the time of primordial follicle formation. Foxl2 disruption thus provides a model for histogenesis and reproductive competence of the ovary.

Chronic morphine induces premature mitosis of proliferating cells in the adult mouse subgranular zone

The birth of cells with neurogenic potential in the adult brain is assessed commonly by detection of exogenous S phase markers, such as bromodeoxyuridine (BrdU). Analysis of other phases of the cell cycle, however, can provide insight into how external factors, such as opiates, influence the cycling of newly born cells. To this end, we examined the expression of two endogenous cell cycle markers in relation to BrdU: proliferating cell nuclear antigen (PCNA) and phosphorylated histone H3 (pHisH3). Two hours after one intraperitoneal BrdU injection, BrdU-, PCNA-, and pHisH3-immunoreactive (IR) cells exhibited similar distribution in the adult mouse subgranular zone (SGZ). Quantitative analysis within the SGZ revealed a relative abundance of cells labeled for PCNA > BrdU >> pHisH3. Similar to our reports in rat SGZ, chronic morphine treatment decreased BrdU- and PCNA-IR cells in mouse SGZ by 28 and 38%, respectively. We also show that pHisH3-IR cells are influenced by chronic morphine to a greater extent (58% decrease) than are BrdU- or PCNA-IR cells. Cell cycle phase analysis of SGZ BrdU-IR cells using triple labeling for BrdU, PCNA, and pHisH3 revealed premature mitosis in chronic morphine-treated mice. These results suggest that morphine-treated mice have a shorter Gap2/mitosis (G(2)/M) phase when compared to sham-treated mice. These findings demonstrate the power of using a combination of exogenous and endogenous cell cycle markers and nuclear morphology to track proliferating cells through different phases of the cell cycle and to reveal the regulation of cell cycle phase by chronic morphine.

Four peptides decrease the number of human pancreatic adenocarcinoma cells

BACKGROUND

Long-acting natriuretic peptide, vessel dilator, kaliuretic peptide and atrial natriuretic peptide are four peptide hormones synthesized by the same gene. Their main known biologic properties are sodium and water excretion and blood pressure lowering in both animals and humans.

METHODS AND MATERIALS

These four peptide hormones, each at their 1-microm concentrations, were evaluated for their ability to decrease the number and/or proliferation of human pancreatic adenocarcinoma cells in culture at 24, 48, 72 and 96 h.

RESULTS

Vessel dilator, long-acting natriuretic peptide, kaliuretic peptide and atrial natriuretic peptide decreased the number of human pancreatic adenocarcinoma cells in culture by 65% (P<0.001), 47% (P<0.01), 37% (P<0.05) and 34% (P<0.05), respectively, within 24 h. This decrease was sustained without any proliferation of the cancer cells occurring in the 3 days following this decrease in number. The mechanism of these peptide hormones' decrease in cancer cell number and antiproliferative effects was a 83% (P<0.001) or greater inhibition of DNA synthesis but not owing to enhanced apoptosis, i.e. programmed cell death. The two known mediators of these peptide hormones' mechanism(s) of action, i.e. cyclic GMP and prostaglandin E2, inhibited DNA synthesis in these adenocarcinoma cells by 51% and 23%, respectively.

CONCLUSIONS

Four peptide hormones significantly decrease the number of pancreatic adenocarcinoma cells within 24 h and inhibit the proliferation of these cells for at least 96 h. Their mechanism of doing so is via inhibition of DNA synthesis mediated in part by cyclic GMP.

Productive HIV infection of resting CD4+ T cells: role of lymphoid tissue microenvironment and effect of immunomodulating agents

The ability of resting CD4+ T cells to support HIV replication is relevant to understanding how the reservoir of HIV-1-infected resting CD4+ T cells is generated, maintained and, hopefully, how it might be reduced or eliminated. We have utilized a tonsillar histoculture system to demonstrate that HIV, particularly X4 strains, can productively infect phenotypically resting CD4+ T cells in vitro and that this event is largely dependent on the lymphoid tissue microenvironment. Highly purified CD4+ tonsillar T cells that lack expression of both cell surface and nuclear antigens characteristic of classic T cell activation produce X4 HIV-1 mRNA, p24, and infectious virus while maintaining a resting phenotype when cultured in a tonsillar tissue microenvironment; in contrast, comparable purified resting CD4+ tonsillar T cells that have been exposed to X4 HIV do not support HIV replication when cultured in the absence of a lymphoid tissue microenvironment. HIV production from phenotypically resting CD4+ T cells is dramatically inhibited by anti-proinflammatory cytokine agents or immunosuppressive cytokines, but is only modestly suppressed by an inhibitor of the cell cycle. The ability of resting CD4+ T cells to support HIV replication in the microenvironment of the lymphoid tissue has implications in the pathogenesis of HIV disease and may provide an additional avenue for therapeutic intervention.

Characterisation of the progression of azaserine-induced rat pancreatic adenocarcinoma by proliferative cell nuclear antigen, basement membrane laminin and trypsinogen immunohistochemistry

The progression of azaserine-induced rat pancreatic adenocarcinoma (AC) was characterised using quantitative and semiquantitative immunohistochemistry for proliferating cell nuclear antigen (PCNA), basement membrane laminin (BML) and trypsinogen (TG). Samples were taken 5-20 months after initiation. High PCNA-labelling indices (PCNA LIs) were measured 5 months after the induction of atypical acinar cell nodules (AACNs), which decreased later and stagnated until a further decline in the month 10 adenomas. Then a second premalignant proliferative wave was observed (month 13) within the adenoma stage. Later, in month 20 differentiated ACs PCNA LIs fell to the host tissue level but were found highest in the month 20 anaplastic ACs indicating a switch to malignant proliferation. Month 20 invasive ACs showed a number of separate proliferative foci. In early AACNs, BML decreased and remained low till the local maximum in the month 13 adenoma. Invasive ACs did not express BML. Month 5 AACN and differentiated AC were TG deficient but anaplastic AC regained its TG expression. However invasive AC was again TG negative. These results are discussed in combination with our previous data on progressional changes of autophagic capacity and microvessel densities.

Ureteral obstruction in neonatal mice elicits segment-specific tubular cell responses leading to nephron loss

BACKGROUND

To elucidate the sequence of renal responses leading to nephron loss in obstructive nephropathy, we examined the evolution of segmental nephron cellular changes consequent to chronic unilateral ureteral obstruction (UUO) in the neonatal mouse.

METHODS

Neonatal mice were subjected to UUO or sham-operation, and kidneys were harvested 5, 12 or 19 days after surgery. Proximal tubules (PT), distal tubules (DT) and collecting ducts (CD) were identified with lectins. Histomorphometric quantitation was made for cellular necrosis, apoptosis, proliferation, tubular dilatation, tubular basement membrane (TBM) thickening, interstitial collagen, and glomerular maturation. The distribution of hypoxic tissue was determined using pimonidazole as a marker. Additional studies were performed by mechanically stretching monolayer cultures of mouse proximal tubular and collecting duct cells, and measuring apoptosis.

RESULTS

Neonatal UUO induced an arrest of glomerular maturation throughout the period of study. Chronic UUO induced hypoxia, tubular necrosis, proliferation, and TBM thickening in the PT, but stimulated apoptosis in the DT and CD. Tubular dilation in the obstructed kidney was most severe in CD and least severe in PT. Tubular cell apoptosis closely paralleled tubular dilation (P < 0.05), and fibrosis surrounding individual tubules also correlated with tubular dilation (P < 0.001). Mechanical stretching of cultured mouse tubular cells induced apoptosis directly proportional to the magnitude of axial strain: apoptosis was consistently greater in CD than in PT cells (P < 0.05).

CONCLUSIONS

Following UUO, the co-localization of hypoxia with cellular proliferation, necrosis, and TBM thickening of the PT is consistent with ischemic injury resulting from vasoconstriction. In contrast, a selective dilation of the distal portion of the nephron (DT and CD), which results from the greater tubular compliance there, leads to stretch-induced epithelial cell apoptosis, along with a progressive peritubular fibrosis. Nephron loss in the obstructed developing kidney likely results from complex, segment-specific cellular responses.

Langerhans cell histiocytosis: an evaluation of histopathological parameters, demonstration of proliferation by Ki-67 and mitotic bodies

PURPOSE

Langerhans cell histiocytosis (LCH) is a disease with a variable clinical manifestation, being localised (SS) or disseminated (MS). The etiology and pathogenesis of LCH is unknown. It is a proliferative disorder of monoclonal origin, but not necessarily neoplastic. In our study we evaluated histopathological parameters and proliferative activity in LCH.

MATERIALS AND METHODS

Infiltrates from 43 patients with LCH were investigated (nSS=32, nMS=11). We evaluated different histopathological parameters semiquantitatively, demonstrating proliferation using immunohistochemistry for Ki-67.

RESULTS

Overall, the histopathological picture of LCH was heterogeneous. The degree of eosinophilia and presence of necroses was significantly higher in SS-infiltrates compared to MS-infiltrates. Mitotic figures were detected in more than half the infiltrates. The Langerhans origin was verified by CD1a. Ki-67 was highly expressed in all but one infiltrate.

CONCLUSIONS

The presence of necrosis and the degree of eosinophilia are related to SS-disease in our study. Ki-67 expression and the presence of mitotic figures indicate that local proliferation contributes to the accumulation of Langerhans cells. Supported by the histopathological appearance of the lesions and a level of Ki-67 expression lower than that of neoplastic tissue, we suggest that LCH is a reactive condition, possibly induced by immunostimulation caused by unknown agents.

Exercise training attenuates coronary smooth muscle phenotypic modulation and nuclear Ca2+ signaling

Physical inactivity is an independent risk factor for coronary heart disease, yet the mechanism(s) of exercise-related cardioprotection remains unknown. We tested the hypothesis that coronary smooth muscle after exercise training would have decreased mitogen-induced phenotypic modulation and enhanced regulation of nuclear Ca(2+). Yucatan swine were endurance exercise trained (EX) on a treadmill for 16-20 wk. EX reduced endothelin-1-induced DNA content by 40% compared with sedentary (SED) swine (P < 0.01). EX decreased single cell peak endothelin-1-induced cytosolic Ca(2+) responses compared with SED by 16% and peak nuclear Ca(2+) responses by 33% (P < 0.05), as determined by confocal microscopy. On the basis of these results, we hypothesized that sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) and intracellular Ca(2+) stores in native smooth muscle are spatially localized to dissociate cytosolic Ca(2+) and nuclear Ca(2+). Subcellular localization of SERCA in living and fixed cells revealed a distribution of SERCA near the sarcolemma and on the nuclear envelope. These results show that EX enhances nuclear Ca(2+) regulation, possibly via SERCA, which may be one mechanism by which coronary smooth muscle cells from EX are less responsive to mitogen-induced phenotypic modulation.

Expression of the bcl-2 family of pro- and anti-apoptotic genes in multiple myeloma and normal plasma cells: regulation during interleukin-6(IL-6)-induced growth and survival

Aberrant expression of genes regulating apoptosis/survival seems to be essential in the stepwise development of human multiple myeloma (MM). In this paper we have compared the expression of bcl-2 family pro- and anti-apoptotic genes in MM cell lines, primary MM cells and normal plasma cells. The Bcl-2, Mcl-1, Bcl-xL/S, Bcl-w, Bax, Bak, and Bad were shown to be expressed in both malignant and non-neoplastic, normal plasma cells. Quantitative analysis revealed that the malignant phenotype seemed to correlate with an elevated expression of Mcl-1, a decreased expression of Bax and, to a lesser extent, an increased Bcl-2/Bax expression ratio. The possible influence of interleukin-6 (IL-6) in regulating the expression of the bcl-2-related genes was also examined. Using the IL-6-dependent MM cell lines U-1958 and U-266-1970 it was clearly shown that IL-6 deprivation induced cell cycle arrest in both cell lines, whereas apoptosis was only detected in the U-1958 cells. Furthermore, the anti-apoptotic proteins Bcl-2, Mcl-1 and Bcl-xL were down-regulated, while the expression of the pro-apoptotic Bax protein was increased. To conclude, we suggest that the expression pattern of the Bcl-2 family of proteins separates the malignant phenotype of MM from normal plasma cells, and that the protecting effect of IL-6 may be conducted via an altered balance between these proteins.

Proliferation and apoptosis in the developing human neocortex

The cell kinetics of the developing central nervous system (CNS) is determined by both proliferation and apoptosis. In the human neocortex at week 6 of gestation, proliferation is confined to the ventricular zone, where mitotic figures and nuclear immunoreactivity for proliferating cell nuclear antigen (PCNA) are detectable. Cell division is symmetric, with both daughter cells reentering mitosis. At week 7, the subventricular zone, a secondary proliferative zone, appears. It mainly gives rise to local circuit neurons and glial cells. Around week 12, the ventricular and subventricular zones are thickest, and the nuclear PCNA label is strongest, indicating that proliferation peaks at this stage. Thereafter, asymmetric division becomes the predominant mode of proliferation, with one daughter cell reentering mitosis and the other one migrating out. Towards late gestation, the ventricular and subventricular zones almost completely disappear and proliferation shifts towards the intermediate and subplate zones, where mainly glial cells are generated. A remnant of the subventricular zone with proliferative activity persists into adulthood. In general, proliferation follows a latero-medial gradient in the neocortex lasting longer in its lateral parts. Apoptotic nuclei have been detected around week 5, occurring in low numbers in the ventricular zone at this stage. Apoptotic cell death increases around midgestation and then spreads throughout all cortical layers, with most dying cells located in the ventricular and subventricular zones. This spatial distribution of apoptosis extends into late gestation. During the early postnatal period, most apoptotic cells are still located in the subcortical layers. During early embryonic development, proliferation and apoptosis are closely related, and are probably regulated by common regulators. In the late fetal and early postnatal periods, when proliferation has considerably declined in all cortical layers, apoptosis may occur in neurons whose sprouting axons do not find their targets.

Adult blood vessels restore host hematopoiesis following lethal irradiation

OBJECTIVE

Accumulating evidence indicates a common stem cell may be responsible for both vasculogenesis and blood cell production during early embryologic development, yet little is known about the fate of these cells during ontogeny. We sought to determine whether hematopoietic potential is associated with normal blood vessels in the adult.

MATERIALS AND METHODS

Segments of adult thoracic aorta or inferior vena cava were transplanted under the kidney capsule of lethally irradiated recipients (1100 cGy). Radioprotection, colony-forming units (CFUs), and the extent of donor-derived hematopoietic constitution were evaluated using both Ly5 congenic and ROSA26 donor mice.

RESULTS

As little as 10 mg of transplanted vascular tissue radioprotected 80% of recipients, gave rise to similar numbers of CFUs as 10(5) bone marrow cells and prevented the development of severe anemia. Bromodeoxyuridine labeling studies revealed cell proliferation within the intima of donor vascular tissue within 48 hours of transplantation. ROSA26 donor-derived vascular cells migrated to the recipient spleen; however, CFUs were of host origin, a finding confirmed using sex-mismatched transplants. Although donor-derived cells were readily detected in the peripheral blood 2 to 3 weeks after transplant, they rapidly declined in frequency to approximately 1.0% by 4 weeks and persisted at these levels for more than 1 year. Bone marrow from rescued primary recipients provided radioprotection after transplantation into secondary recipients; however, only CD3(+) donor-derived cells were detected.

CONCLUSION

These findings demonstrate the presence of a population of cells within normal adult vascular tissue that has the capacity to protect host hematopoietic stem cells from radiation-induced death.

Involvement of mouse Rev3 in tolerance of endogenous and exogenous DNA damage

The Rev3 gene of Saccharomyces cerevisiae encodes the catalytic subunit of DNA polymerase zeta that is implicated in mutagenic translesion synthesis of damaged DNA. To investigate the function of its mouse homologue, we have generated mouse embryonic stem cells and mice carrying a targeted disruption of Rev3. Although some strain-dependent variation was observed, Rev3(-/-) embryos died around midgestation, displaying retarded growth in the absence of consistent developmental abnormalities. Rev3(-/-) cell lines could not be established, indicating a cell-autonomous requirement of Rev3 for long-term viability. Histochemical analysis of Rev3(-/-) embryos did not reveal aberrant replication or cellular proliferation but demonstrated massive apoptosis in all embryonic lineages. Although increased levels of p53 are detected in Rev3(-/-) embryos, the embryonic phenotype was not rescued by the absence of p53. A significant increase in double-stranded DNA breaks as well as chromatid and chromosome aberrations was observed in cells from Rev3(-/-) embryos. The inner cell mass of cultured Rev3(-/-) blastocysts dies of a delayed apoptotic response after exposure to a low dose of N-acetoxy-2-acetylaminofluorene. These combined data are compatible with a model in which, in the absence of polymerase zeta, double-stranded DNA breaks accumulate at sites of unreplicated DNA damage, eliciting a p53-independent apoptotic response. Together, these data are consistent with involvement of polymerase zeta in translesion synthesis of endogenously and exogenously induced DNA lesions.

Cell proliferation during blastema formation in the regenerating teleost fin

Epimorphic regeneration in teleost fins occurs through the establishment of a balanced growth state in which a blastema gives rise to all the mesenchymal cells, whereas definite areas of the epidermis proliferate leading to its extension, thus, allowing the enlargement of the whole structure. This type of regeneration involves specific mechanisms that temporally and spatially regulate cell proliferation. To understand how the blastema is formed and how this growth situation is set up, we investigated cell proliferation patterns in the regenerating fin of the goldfish Carassius auratus from the time of amputation to that of blastema formation by using proliferating cell nuclear antigen immunostaining and bromodeoxyuridine labeling. Wound closure and apical epidermal cap formation took place by epidermal migration and re-arrangement, without the contribution of cell proliferation. As soon as the apical cap had formed, the epidermis started to proliferate at its lateral surfaces, in which all layers maintained cycling for the duration of the studied process. The distal epidermal cap, on the contrary, presented very few cycling cells, and its cytoarchitecture was indicative of continuous remodeling due to ray growth. The basal layer of this epidermal cap showed a typical morphology and remained nonproliferative whilst in contact with the proliferating blastema. Proliferation in the mesenchymal compartment of the ray started far from the amputation plane. Subsequently, cycling cells approached that location, until they formed the blastema in contact with the apical epidermal cap. Differences observed between the epidermis and mesenchyma, regarding activation of the cell cycle and the establishment of proliferative patterns, suggest that differential mechanisms regulate cell proliferation in each of these compartments during the initial stages of regeneration.

Epithelial cell dynamics in rabbit cecum and proximal colon P1

The large intestine of mammals has long been viewed as an osmoregulatory organ, and evidence suggests that fluid and solute transport mechanisms within the intestine are heterogeneous, varying depending on the particular segment involved. Variations in function are often matched by morphological correlates, but despite the widespread use of rabbit large intestine as an experimental model, there is a lack of knowledge about the cellular makeup and dynamics in the colonic mucosal epithelium. The presence of mitotic figures and immunohistochemical localization of proliferating cell nuclear antigen (PCNA) were used to identify the proliferative zone(s). Cellular migration patterns were determined through the use of the thymidine analog 5-bromo-2-deoxyuridine (BrdU) over a 24-, 48-, and 72-hr period. Apoptotic nuclei were identified utilizing terminal deoxynucleotidyl transferase d-UTP nick-end labeling (TUNEL). Both cecum and the initial portion of the proximal colon (P1) exhibited a proliferative zone at or near the crypt base, and migration proceeded upwards toward the surface epithelium lining the intestinal lumen, where apoptosis occurred Turnover time of crypt columnar cells was determined to be about 3 days; that of mucous cells was estimated to be about 5 weeks. Rabbit cecum and proximal colon P1 are similar in their cellular morphology and epithelial cell kinetics. In both, the major proliferative zone is located at or near the crypt base, from which crypt columnar cells migrate toward the lumenal surface epithelium over a period of 3 days. Goblet cell turnover rate is much slower than that of columnar cells.

Regulation of gastric epithelial cell development revealed in H(+)/K(+)-ATPase beta-subunit- and gastrin-deficient mice

The gastric H(+)/K(+)-ATPase is essential for normal development of parietal cells. Here we have directly assessed the role of the H(+)/K(+)-ATPase beta-subunit (H/K-beta) on epithelial cell development by detailed quantitation of the epithelial cell types of the gastric mucosa of H/K-beta-deficient mice. H/K-beta-deficient mice had a 3.1-fold increase in the number of immature cells per gastric unit; however, the numbers of surface mucous and parietal cells were similar to those in the gastric units of wild-type mice. The effect of elevated gastrin levels in the H/K-beta-deficient mice was determined by producing mice that are also deficient in gastrin. We demonstrated that the increased production of immature cells and resulting hypertrophy is caused by the overproduction of gastrin. However, the depletion of zymogenic cells, which is another feature of H/K-beta-deficient mice, is independent of hypergastrinemia. Significantly, parietal cells of H/K-beta- and gastrin-deficient mice had abnormal secretory membranes and were devoid of resting tubulovesicular membranes. Together these data suggest a homeostatic mechanism limiting the number of immature cells that can develop into end-stage epithelial cells and indicate a direct role for H/K-beta in the development of mature parietal cells.

Long-term impact of smoking on lung epithelial proliferation in current and former smokers

BACKGROUND

Lung cancer risk remains elevated for many years after quitting smoking. To assess using proliferation indices in bronchial tissues as an intermediate endpoint biomarker in lung cancer chemoprevention trials, we determined the relationship between the extent, intensity, and cessation of tobacco smoking and proliferative changes in bronchial epithelial biopsy specimens.

METHODS

Bronchial biopsy specimens were obtained from up to six epithelial sites in 120 current smokers (median pack-years, 42) and 207 former smokers (median pack-years, 40; median quit-years, 8.1). Sections from the paraffin-embedded specimens were stained with hematoxylin--eosin to determine the metaplasia index and with an antibody to Ki-67 to determine the proliferative (labeling) index for the basal and parabasal (Ki-67 PLI) layers. All statistical tests were two-sided.

RESULTS

Biopsy sites with metaplasia had statistically significantly higher Ki-67-labeling indices than those without metaplasia (P<.001) in both current and former smokers. Increased proliferation was observed in multiple biopsy sites, with the average Ki-67 PLI of the subject strongly correlating with the metaplasia index (r =.72 for current smokers; P<.001), even in sites without metaplasia (r =.23 for current smokers; P<.001). In current smokers, the Ki-67 PLI was associated with the number of packs smoked/day (P =.02) but not with smoking years or pack-years. In subjects who had quit smoking, the Ki-67 PLI dropped statistically significantly within 1 year (P =.008) but remained detectable for more than 20 years, even in the absence of squamous metaplasia.

CONCLUSION

Smoking appears to elicit a dose-related proliferative response in the bronchial epithelia of active smokers. Although the proliferative response decreased gradually in former smokers, a subset of individuals had detectable proliferation for many years and may benefit from targeted chemoprevention. Bronchial epithelial proliferation, measured by Ki-67, may provide a useful biomarker in the assessment of lung cancer risk and in the response to chemopreventive interventions.

Cell proliferation in the loop of henle in the developing rat kidney

In the developing rat kidney, there is no separation of the medulla into an outer and inner zone. At the time of birth, ascending limbs with immature distal tubule epithelium are present throughout the renal medulla, all loops of Henle resemble the short loop of adult animals, and there are no ascending thin limbs. It was demonstrated previously that immature thick ascending limbs in the renal papilla are transformed into ascending thin limbs by apoptotic deletion of cells and transformation of the remaining cells into a thin squamous epithelium. However, it is not known whether this is the only source of ascending thin limb cells or whether cell proliferation occurs in the segment undergoing transformation. This study was designed to address these questions and to identify sites of cell proliferation in the loop of Henle. Rat pups, 1, 3, 5, 7, and 14 d old, received a single injection of 5-bromo-2'-deoxyuridine (BrdU) 18 h before preservation of kidneys for immunohistochemistry. Thick ascending and descending limbs were identified by labeling with antibodies against the serotonin receptor, 5-HT(1A), and aquaporin-1, respectively. Proliferating cells were identified with an antibody against BrdU. BrdU-positive cells in descending and ascending limbs of the loop of Henle were counted and expressed as percentages of the total number of aquaporin-1-positive and 5-HT(1A)-positive cells in the different segments. In the developing kidney, numerous BrdU-positive nuclei were observed in the nephrogenic zone. Outside of this location, BrdU-positive tubule cells were most prevalent in medullary rays in the inner cortex and in the outer medulla. BrdU-labeled cells were rare in the papillary portion of the loop of Henle and were not observed in the lower half of the papilla after 3 d of age. BrdU-labeled nuclei were not observed in segments undergoing transformation or in newly formed ascending thin limb epithelium. It was concluded that the growth zone for the loop of Henle is located around the corticomedullary junction, and the ascending thin limb is mainly, if not exclusively, derived from cells of the thick ascending limb.

Ratio of proliferating cell nuclear antigen-positive nuclei to total cell number is higher in day 7 than in day 8 vitrified in vitro-produced bovine embryos

The aim of the present study was to find a reliable functional criterion for the evaluation of the proliferation potential of bovine in vitro-produced embryos. We used immunocytochemical detection of proliferating cell nuclear antigen (PCNA) combined with propidium iodide (PI) staining and subsequent confocal laser scanning microscopy together with routine morphological evaluation under a stereomicroscope to study fresh Day 7, 8, and 9, and cryopreserved Day 7 and 8 embryos. The ratio of PCNA/PI-positive nuclei was equal in fresh Day 7 and Day 8 embryos and significantly lower in Day 9 embryos. In general, Day 7 embryos tolerated the cryopreservation treatments better than Day 8 embryos. Vitrification in normal straws was especially detrimental to Day 8 embryos. In fresh Day 7 and 8 embryos, the PCNA results were in agreement with stereomicroscopic evaluation. However, in Day 9 fresh and in Day 7 and 8 treated embryos, the missing PCNA revealed disorders that were not observed under morphological evaluation. PCNA immunocytochemistry is an effective method to obtain information about the functional state of nuclei. The ratio of PCNA-positive nuclei can provide more information and numerical data about the developmental potential of bovine embryos after cryopreservation.

A gross and microscopical morphometric evaluation of feline large intestinal anatomy

The objective of this study was to examine measurable parameters that could be used to describe the gross and microscopical anatomy of the feline colon, which has not been previously characterized. Post-mortem data were collected from 35 specific pathogen-free cats. Gross morphometric data (total colonic length, wet weight, number of lymphoid aggregates) were collected together with microscopical measurement of crypt depth and numbers, intra-epithelial lymphocyte numbers and the number of proliferating cell nuclear antigen (PCNA)-positive cells and their relative position within the crypt. Colonic length as a percentage of intestinal length was remarkably constant (20.9+/-2.0%). Crypt depth, however, showed considerable inter-cat variation (149-688 microm); the crypts became deeper with distance from the anus. Cellular proliferation was predominantly in the lower part of the crypt, and the numbers of PCNA-positive cells increased with distance from the anus. The number of lymphoid aggregates varied with distance from the anorectum and appeared to reflect the bacterial load. Intra-epithelial lymphocytes were relatively sparse (3.9+/-2.7/100 epithelial cells); they showed considerable inter-cat variation but did not vary with distance from the anus. These data suggest that to improve the interpretation of morphometric parameters by reducing inter-cat variation, samples should be taken at a consistent distance from the anus, broad reference ranges having now been established.

Vein adaptation to arterialization in an experimental model

PURPOSE

The events preceding myointimal thickening in vein grafts after vascular reconstructions are not well characterized. Indeed, the injury response associated with vein graft arterialization may be different than that observed in the balloon angioplasty model. Therefore, we used a rat model to study the early cellular response after arterialization of vein grafts.

METHODS

Epigastric veins were placed as femoral artery interposition grafts in 37 male Lewis rats (weight range, 350-400 g). Vein grafts and contralateral epigastric veins were harvested at different time points (6 hours, 1 day, 2 days, 3 days, 7 days, 14 days, 21 days, 30 days, and 70 days). Tissue specimens were processed for histology and immunohistochemistry with antibodies for the proliferating cell nuclear antigen (PCNA) and for different cell types. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was used as a means of determining the presence of apoptosis. Electron microscopy was used as means of assessing the integrity of the endothelial cell surface (SEM) and confirming the presence of apoptosis (TEM). Specimens were also snap frozen in liquid nitrogen for RNA isolation and molecular analysis.

RESULTS

At 1 day, endothelial denudation with platelet deposition on the surface was shown by means of SEM. Both apoptosis and necrosis of smooth muscle cells (SMCs) were present in the media, along with monocyte infiltration. Cellular proliferation and apoptosis were most intense within the first week of implantation. PCNA staining was first seen in the adventitial fibroblasts and microvessels, then in the medial SMCs at 3 days. With reverse transcriptase polymerase chain reaction, upregulation of vascular endothelial growth factor (VEGF) messenger RNA (mRNA) was noted at 1 day. Myointimal thickening progressively developed, with no apparent diminution of the luminal area as long as 70 days after implantation. By means of the analysis of the transforming growth factor beta1, mRNA showed expression during intimal thickening and accumulation of extracellular matrix. Reendothelialization was complete at 30 days.

CONCLUSIONS

These observations indicate that the cellular composition in our vein graft model is similar to human stenotic explants. Endothelial denudation is observed in rat vein grafts with complete regeneration by 30 days. VEGF mRNA is upregulated at 1 day, followed by proliferation of microvessel endothelial cells in the adventitia. Cellular proliferation and apoptosis are minimal after 21 days, with progressive intimal thickening likely to be the result of matrix accumulation.

Defect in germ cells, not in supporting cells, is the cause of male infertility in the jsd mutant mouse: proliferation of spermatogonial stem cells without differentiation

C57BL/6 (B6)-jsd/jsd male mice are sterile because of lack of spermatogenesis. To find the cause of the deficient spermatogenesis, we have examined whether the mutation phenotype is the result of a defect in germ cells or in supporting cells using germ cell transplantation. In the seminiferous tubules of B6-jsd/jsd mutant mice, donor germ cells derived from the wild type GFP transgenic mouse (B6-+/+GFP) were able to undergo complete spermatogenesis, indicating that the juvenile spermatogonial depletion (jsd/jsd) mouse possesses normal supporting cell functions. In contrast, undifferentiated spermatogonia derived from B6-jsd/jsd mice were unable to differentiate in the seminiferous tubules of W/W v mice, even if the mutant germ cells successfully settled in the tubules. These results demonstrate that the deficiency in spermatogenesis of B6-jsd/jsd mice can be ascribed to a defect in spermatogonia but not in their supporting cell environment. Furthermore, the defect in B6-jsd/jsd spermatogonia is not in their ability to proliferate, but in their differentiation and may result from their hypersensitivity to high concentrations of androgen in the testis.

Impact of neoadjuvant chemotherapy on Ki-67 and PCNA labeling indices for esophageal squamous cell carcinomas

PURPOSE

The effects of neoadjuvant chemotherapy (CT) on Ki-67 and proliferating cell nuclear antigen (PCNA) labeling index (LI) were analyzed, using biopsy and surgical specimens of esophageal cancer.

METHOD AND MATERIALS

Immunohistochemical staining for Ki-67 and PCNA was performed for biopsy and surgical specimens of 35 patients with esophageal squamous cell carcinoma. Seventeen patients were treated with neoadjuvant CT (CT group), while no preoperative treatment was performed for the remaining 18 patients (control group). As neoadjuvant CT, cisplatin of 50 mg/body/week was administered 2-5 times (100-250 mg in total) until 7-10 days before subtotal esophagectomy.

RESULT

Significant correlation between the LIs of biopsy and surgical specimens was observed for the control group (p = 0.006 for Ki-67 and p = 0.005 for PCNA), although both LIs of surgical specimens were significantly higher than those of biopsy specimens (p < 0.05). However, no significant correlation between LIs of biopsy specimens and those of surgical specimens was observed for the CT group. In addition, the LIs of the surgical specimens of the CT group were significantly lower than the LIs of the control group (p < 0.005 for Ki-67 and p < 0.05 for PCNA). Significant decrease in Ki-67 LI after neoadjuvant CT was noted especially for well or moderately differentiated squamous cell carcinomas and/or tumors treated with high-dose cisplatin (150-250 mg).

CONCLUSION

Significant correlation of Ki-67 and PCNA LIs between biopsy and surgical specimens was demonstrated for the control group. Neoadjuvant CT decreased the percentage of cycling and proliferative tumor cells of esophageal cancer.

A zonal comparison of MIB1-Ki67 immunoreactivity in benign and malignant melanocytic lesions

Differentiation between malignant melanomas and benign nevi can sometimes be difficult by conventional histopathology, and additional diagnostic markers may be helpful. This study investigated the immunoreactivity of the cell proliferation marker MIB1-Ki67 in 23 compound nevi, 17 dysplastic nevi, 8 Spitz nevi (SN), and 24 malignant melanomas (MMs) and evaluated its ability in separating benign nevi from MMs. In each lesion, the average number (percentage) of MIB1-positive nuclei (%MIB1-Mean) and the maximal number (percentage) of MIB1-positive nuclei (%MIB1-Max) were determined from each of the superficial, middle, and deep dermal zones of the lesion as well as from the entire lesion. The %MIB1-Max was determined from subjectively selected area(s) of high count. Malignant melanomas had a significantly greater %MIB1-Mean and %MIB1-Max than all benign nevi in all individual zones and in the entire lesion (p < 0.05). Discriminant analysis showed that the %MIB1-Mean and %MIB1-Max counted from the whole lesions had better discriminating abilities than from the individual zones. By using the %MIB1-Mean from all zones, all lesions except 1 SN and 3 MMs could be correctly classified as benign or malignant. When using the %MIB1-Max from all zones, all but 2 SN could be correctly separated as benign or malignant. Thus, MIB1-Ki67 immunoreactivity closely correlates with the benignancy or malignancy of melanocytic lesions and may assist in the differentiation of benign nevi from MMs.

Co-expression of p53 and bcl-2 may correlate to the presence of epstein-barr virus genome and the expression of proliferating cell nuclear antigen in nasopharyngeal carcinoma

Epstein-Barr virus (EBV) has been well documented in the aetiology of nasopharyngeal carcinoma (NPC), although its role as well as the genetic basis in the genesis of NPC have not been elucidated. The p53 gene mutations are infrequently found in NPC, but the expression of p53 protein, as well as bcl-2 oncoprotein, has been reported in a high percentage of cases, and also in association with EBV. Proliferating cell nuclear antigen (PCNA) has also been shown to be increased in NPC, suggesting its association among the overexpression of p53 and bcl-2 oncoprotein. We undertook this study to evaluate the correlation among these abnormalities in the development of NPC. The expression of p53 protein, bcl-2 oncoprotein, and the level of PCNA were investigated by immunohistochemistry in 53 patients with NPC. Twenty tissue samples from these patients were studied for p53 gene mutations by single strand conformation polymorphism (SSCP) and DNA sequencing as well as EBV genomes by polymerase chain reaction. Among the 53 specimens, 42 (79%) showed expression of p53 protein and 40 (75%) gave positive result for bcl-2 oncoprotein. A significant association was found between p53 expression and bcl-2 oncoprotein (P=0.002; Fisher's exact test) with 68% of the patients showing coexpression of both markers. The PCNA labelling index in the 53 patients varied from 5% to 80%. High PCNA labelling index was frequently found in the patients with overexpression of p53 protein and bcl-2 oncoprotein. The PCNA index in patients with p53 expression was significant higher than in those without p53 expression (P=0.002). Of the 20 patients, p53 mutations were found in four cases. EBV genomes were detected in 14 cases of which 12 cases showed overexpression of both p53 and bcl-2 and one case with only p53 expression and one case with bcl-2 expression. EBV genomes were detected in two cases with p53 mutations. We conclude that EBV is the important etiologic factor in NPC which may be involved in p53 and bcl-2 overexpression. The mutant p53 protein is correlated to deregulation of PCNA. p53 mutations participate in a small proportion of the tumorigenesis.

Down-regulation of insulin-like growth factor-I receptor and insulin receptor substrate-1 expression in advanced human breast cancer

The ligands, receptors and related signaling proteins of the insulin-like growth factor family are involved in the regulation of breast-cancer cell growth. We investigated the expression pattern of insulin-like growth factor-I receptor (IGF-IR), insulin receptor (IR) and insulin receptor substrate-1 (IRS-1), a core downstream signaling protein, in 69 primary breast-cancer specimens of different grades and in 21 control tissues by immunohistochemistry. In addition, cell proliferation (percentage of Ki67(+) nuclei) and estrogen receptor (ER) expression were determined. IGF-IR, IRS-1 and IR were expressed mainly in epithelial cells. IRS-1 and IGF-IR were expressed at high levels in control tissues and in well and moderately differentiated carcinomas but at low levels in poorly differentiated breast cancers. IR expression did not show a significant correlation with the differentiation grade of the tissues investigated. Statistical analysis (ROC analysis for tumor grade) demonstrated that down-regulation of IGF-IR and IRS-1 correlated better with tumor progression than reduction of ER expression or increase in cell proliferation, IGF-IR showing the best correlation, followed by IRS-1 and, less significant, ER and Ki67. Our findings clearly show that progression of breast cancer is accompanied by a reduction of IGF-IR/IRS-1 expression and that IGF-IR/IRS-1 expression inversely correlates with high proliferation rate in dedifferentiated breast cancers. The strong correlation of IGF-IR and IRS-1 down-regulation with tumor progression suggests the use of IGF-IR and IRS-1 as a novel set of marker proteins for tumor grading.

The effect of hormone replacement therapy on the number and the proliferation index of endometrial leukocytes

This study aimed to determine the changes in endometrial leukocyte subpopulations under sequential hormone replacement therapy (HRT) during the late progestogenic phase. The number of leukocytes was determined using immunohistochemistry utilizing monoclonal antibodies to CD45 (total leukocytes), CD56 (endometrial granulated lymphocytes), CD3 (T-cells), and CD68 (macrophages). Leukocyte proliferation was demonstrated using in-situ hybridization with a histone probe, and the proliferation index was determined using double labelling for Ki67 (Mib1). Compared to the corresponding phase of the physiological cycle, sequential HRT-treated endometrium exhibited a 95% increase in CD45(+) cells (P < 0.05), a 130% increase in CD56(+) cells (P < 0.05), and a 113% increase in CD3 cells. There was a non-statistically significant drop in the number of CD68(+) cells. The number of proliferating leukocytes increased in sequential HRT endometrium.

Differentiation of malignant lymphoma and non-lymphoma by an occlusive dressing method employing bromodeoxyuridine

Although lymphoma cells can proliferate in skin tissue, lymphocytes which have infiltrated the skin due to inflammatory changes are generally unable to do so. It may be possible to differentiate malignant lymphomas from benign lymphocytic infiltrations in skin tissue by detection of cell cycle-related antigens. We developed a novel in vivo method for studying the cell kinetics of human skin using bromodeoxyuridine (BrdU) with an occlusive dressing. Following the application of BrdU, BrdU-labeled lymphoid cells were counted in the dermis. The patients studied included 22 with various types of lymphomas (lymphoma group) and 22 with different forms of inflammatory skin disease (non-lymphoma group). Skin specimens were obtained after applying occlusive adhesive plasters containing 2% BrdU dissolved in 0.9% sodium chloride solution and were then immunostained with anti-BrdU monoclonal antibody. The average percentages of labeled cells were 15.9 +/- 7.6% for the lymphoma group and 4.7 +/- 2.6% for the non-lymphoma group. This difference was statistically significant (p < 0.0001). Using this method, malignant lymphomas and benign lymphocytic infiltrations of the skin could be differentiated by counting BrdU-labeled lymphoid cells, and this method could help in determining a prognosis.

Alpha-fetoprotein-producing gastric cancer: histochemical analysis of cell proliferation, apoptosis, and angiogenesis

OBJECTIVE

Alpha-fetoprotein (AFP)-producing gastric cancer has been associated with a poor prognosis. In the present study, the cell proliferation, apoptosis, and angiogenesis of this cancer were studied histochemically to determine its malignant potential.

METHODS

Tissue samples were taken from four patients with AFP-producing gastric cancer and 26 patients with AFP-negative gastric cancer. Cell proliferation was evaluated by Ki-67 immunostaining, and the Ki-67 labeling index (LI) was determined. Apoptosis was studied by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling method, and the apoptotic index was determined. Angiogenesis was evaluated by measuring the microvessel density using factor VIII immunostaining, and immunostainings for vascular endothelial growth factor and thymidine phosphorylase were performed.

RESULTS

The Ki-67 LI of the AFP-producing gastric cancers was significantly higher than that of the AFP-negative gastric cancers (p < 0.01). The apoptotic index of the AFP-producing gastric cancers was significantly lower than that of the AFP-negative gastric cancers (p < 0.01). The microvessel density of the AFP-producing gastric cancers was significantly higher than that of the AFP-negative gastric cancers (p < 0.01). Vascular endothelial growth factor expression was observed in all four of the AFP-producing gastric cancers, whereas thymidine phosphorylase was not expressed in any of the AFP-producing gastric cancers.

CONCLUSIONS

These results suggest that AFP-producing gastric cancers have high malignant potential (high proliferative activity, weak apoptosis, and rich neovascularization) compared with that of AFP-negative gastric cancers. These biological characteristics of AFP-producing gastric cancer reflect the aggressive behavior and the poor prognosis of patients with this type of cancer.