Widespread activation of microglial cells in the hippocampus of chronic epileptic rats correlates only partially with neurodegeneration.

Activation of microglial cells (brain macrophages) soon after status epilepticus has been suggested to be critical for the pathogenesis of mesial temporal lobe epilepsy (MTLE). However, microglial activation in the chronic phase of experimental MTLE has been scarcely addressed. In this study, we questioned whether microglial activation persists in the hippocampus of pilocarpine-treated, epileptic Wistar rats and to which extent it is associated with segmental neurodegeneration. Microglial cells were immunostained for the universal microglial marker, ionized calcium-binding adapter molecule-1 and the activation marker, CD11b (also known as OX42, Mac-1). Using quantitative morphology, i.e., stereology and Neurolucida-based reconstructions, we investigated morphological correlates of microglial activation such as cell number, ramification, somatic size and shape. We find that microglial cells in epileptic rats feature widespread, activation-related morphological changes such as increase in cell number density, massive up-regulation of CD11b and de-ramification. The parameters show heterogeneity in different hippocampal subregions. For instance, de-ramification is most prominent in the outer molecular layer of the dentate gyrus, whereas CD11b expression dominates in hilus. Interestingly, microglial activation only partially correlates with segmental neurodegeneration. Major neuronal death in the hilus, CA3 and CA1 coincides with strong up-regulation of CD11b. However, microglial activation is also observed in subregions that do not feature neurodegeneration, such as the molecular and granular layer of the dentate gyrus. This in vivo study provides solid experimental evidence that microglial cells feature widespread heterogeneous activation that only partially correlates with hippocampal segmental neuronal loss in experimental MTLE.

Adipose tissue displays trophic properties on normal lung cellular components without promoting cancer cells growth.

Surgical removal is the mainstay for early lung cancer treatment and persistent air leaks represent one of the most common clinical complications after lung surgery. Adipose tissue transplantation has been proposed as a new strategy for regenerative therapy after breast cancer surgery; however its efficacy and safety of lung tissue healing after lung resections are unknown. The purpose of this study was to test the biological activity of adipose tissue to facilitate lung tissue healing and evaluate its effect on cancer cells growth, thus providing insight for a possible clinical application. Different in vitro cellular models were used to prove the potential biologic effect of autologous fat tissue (AFT) in repairing injured lung tissue, and in vivo xenograft models were used to evaluate tumor promoting potential of AFT on putative residual cancer cells. Treatment of both embryonic (WI-38) and adult lung fibroblasts and of normal bronchial epithelial cells (HBEC-KT) with AFT samples, harvested from subcutaneous tissue layer of 20 patients undergoing pulmonary metastasectomy, improved wound healing and cell proliferation indicating a trophic effect on both mesenchymal and epithelial cell types. Conversely AFT-conditioned medium was unable to stimulate in vitro proliferation of a lung adenocarcinoma reporter cellular system (A549). Moreover, co-injection of AFT and A549 cells in nude mice did not promote engraftment and progression of A549 cells. These preclinical findings provide preliminary evidence on the potential efficacy of AFT to accelerate lung tissue repair without undesired tumor promoting effects on putative residual cancer cells.

Redistribution of astrocytic glutamine synthetase in the hippocampus of chronic epileptic rats.

Glutamine synthetase (GS) is an astrocytic enzyme, which catalyzes the synthesis of glutamine from glutamate and ammonia. In the central nervous system, GS prevents glutamate-dependent excitotoxicity and detoxifies nitrogen. Reduction in both expression and activity of GS was reported in the hippocampus of patients with temporal lobe epilepsy (TLE), and this reduction has been suggested to contribute to epileptogenesis. In this study, we characterized hippocampal GS expression in the pilocarpine model of TLE in Wistar rats by means of stereology and morphometric analysis. Neither the GS positive cell number nor the GS containing cell volume was found to be altered in different hippocampal subregions of chronic epileptic rats when compared with controls. Instead, redistribution of the enzyme at both intracellular and tissue levels was observed in the epileptic hippocampus; GS was expressed more in proximal astrocytic branches, and GS expressing astrocytic somata was located in closer proximity to vascular walls. These effects were not due to shrinkage of astrocytic processes, as revealed by glial fibrillary acidic protein staining. Our results argue for GS redistribution rather than downregulation in the rat pilocarpine model of TLE. The potential contribution of increased GS perivascular affinity to the pathogenesis of epilepsy is discussed as well.

FHIT and p53 status and response to platinum-based treatment in advanced non-small cell lung cancer.

Inactivation of the FHIT and TP53 genes is frequently observed in primary non-small cell lung cancers (NSCLC) and cell lines and may contribute to resistance to apoptotic stimuli elicited by various anti-tumor drugs. To evaluate a possible relationship between FHIT and TP53 status and response to platinum-analogue regimens, we retrospectively selected 55 NSCLC patients treated with carboplatin/gemcitabine. Pre-treatment formalin fixed biopsies were analyzed for FHIT and p53 protein expression by immunohistochemistry and representative micro dissected tissue for TP53 mutations by DG-DGGE/sequencing. The FHIT-negative immunophenotype (FHIT-, pathologic) was found in 33 patients (60%) and p53 over expression/mutation (p53+, pathologic) in 25 patients (45%). The FHIT-/p53+ combination was present in 12 patients (22%). Overall, there was partial response in 21 patients (38%), with subgroup response rates of 33% in FHIT+/p53-, 46% in FHIT+/p53+, 38% in FHIT-/p53- and 33% in FHIT-/p53+ patients. Median progression-free survival (PFS) was 9.6, 7.9, 6.8 and 5.9 months and median overall survival (OS) was 12.8, 11.9, 10.5 and 8.7 months in the four groups, respectively. The Group comparison showed significantly worse PFS (p=0.04) in FHIT-/p53+ than the other groups. There was no significant difference in OS between the groups. A trend (p=0.07) for shorter OS was found in FHIT- cases suggesting that NSCLC tumors carrying this feature are less responsive to treatment. This retrospective study indicates that FHIT-/p53+ status might be a biological variable influencing the efficacy of carboplatin/gemcitabine treatment in NSCLC.

Effect of inducible FHIT and p53 expression in the Calu-1 lung cancer cell line.

Loss of FHIT expression and p53 mutations are critical events in the early stages of lung carcinogenesis. The restoration of Fhit function in FHIT-negative cancer cells has been reported to cause tumour suppression by inhibition of cell proliferation and/or activation of apoptotic pathways. However, the studies designed to elucidate the biological role of Fhit and its potential interaction with p53 have produced conflicting results. We investigated here the effects of the simultaneous restoration of FHIT and p53 in Calu-1 cells by using a hormone-inducible gene expression system. We demonstrate that the restoration of FHIT expression reinforces the anti-proliferative effect associated with the simultaneous replacement of p53. Indeed, a more pronounced inhibition of cell proliferation associated with an earlier and higher induction of p21(waf1) mRNA and protein expression was observed in Fhit/p53-expressing cells compared with cells expressing p53 alone. This effect was not due to Fhit-mediated up-regulation of p53 expression; in fact p53 protein was expressed at the same level in both FHIT-positive and FHIT-negative cell clones. Consistent with this result, Fhit did not affect the expression of MDM2, a protein known to interact directly with p53 and target p53 for proteolytic degradation, thus down-regulating its activity.

Increased sensitivity to cisplatin in non-small cell lung cancer cell lines after FHIT gene transfer.

To evaluate the relevance of fragile histidine triad (FHIT) status in relation to drug treatment, we analyzed the sensitivity of the Fhit-negative non-small cell lung cancer (NSCLC) cell line NCI-H460 to different drugs, after treatment with an adenoviral vector expressing the FHIT transgene. Expression of Fhit resulted in reduced sensitivity to etoposide, doxorubicin, and topotecan. This feature was associated with Fhit-induced downregulation of DNA topoisomerases I and II. In contrast, expression of Fhit did not modulate sensitivity to Taxol, but produced a slight increase in sensitivity to cisplatin, as shown by colony-forming assays. Analysis of apoptosis revealed that, after cisplatin exposure, the number of apoptotic cells was two-fold higher in Fhit-expressing H460 cells. Moreover, it appeared that wildtype p53 was required for sensitization to cisplatin because the effect was marginal in A549 and Calu-1 cells, where the p53 pathway is altered and simultaneous restoration of p53 and Fhit in Calu-1 cells increased cisplatin sensitivity. Fhit could also partially restore sensitivity to cisplatin in Bcl-2- and Bcl-x(L)-overexpressing H460 cells that are normally resistant to this drug. Our results support the possible relevance of FHIT in cisplatin-based chemotherapy as well as in the reversal of drug resistance in NSCLC.

Use of the probasin promoter ARR2PB to express Bax in androgen receptor-positive prostate cancer cells.

BACKGROUND: Adenovirus-mediated overexpression of the apoptosis-inducing protein Bax can induce apoptosis in prostate cancer cell lines. Constitutive overexpression of Bax could result in unwanted apoptosis in every site of accidental Bax accumulation in vivo. Therefore, we developed an adenoviral construct (Av-ARR2PB-Bax) in which the probasin promoter, modified to contain two androgen response elements, drives Bax expression. This promoter would be expected to limit expression of Bax to cells expressing the androgen receptor. METHODS: A variety of androgen receptor (AR)-positive and -negative cell lines of prostatic or nonprostatic origin were infected with Av-ARR2PB-Bax or a control virus, Av-ARR2PB-CAT, in which the same promoter drives expression of the chloramphenicol acetyl transferase-reporter gene. Bax expression and apoptosis in vitro were assessed by western blot analysis. Tumor size and apoptosis in vivo were assessed after four weekly injections of Av-ARR2PB-Bax or Av-ARR2PB-CAT into subcutaneous LNCaP xenografts growing in uncastrated male mice. All statistical tests were two-sided. RESULTS: Bax was overexpressed in an androgen-dependent way in AR-positive cell lines of prostatic origin but not in AR-positive cells of nonprostatic origin or in AR-negative cell lines of either prostatic or nonprostatic origin. The androgen dihydrotestosterone activated apoptosis in LNCaP cells infected with Av-ARR2PB-Bax but not in those infected with Av-ARR2PB-CAT. Av-ARR2PB-Bax-injected LNCaP xenograft tumors decreased in tumor size from 34.1 mm3 (95% confidence interval [CI] = 25.1 mm3 to 43.1 mm3) to 24.6 mm3 (95% CI = -2.5 mm3 to 51.7 mm3), but the difference was not statistically significant (P =.5). Tumors injected with Av-ARR2PB-CAT increased in size, from 28.9 mm3 (95% CI = 12.7 mm3 to 45.1 mm3) to 206 mm3 (95% CI = 122 mm3 to 290 mm3) (P =.002) and contained statistically significant more apoptotic cells (23.3% [95% CI = 21.1% to 25.6%] versus 9.5% [95% CI = 8.0% to 11.1]) (P<.001). CONCLUSIONS: Av-ARR2PB-Bax induces androgen-dependent therapeutic apoptosis in vitro and in vivo by activating apoptosis in AR-positive cells derived specifically from prostatic epithelium and does not affect nonprostatic cells.

Overexpression of BCL-X(L) underlies the molecular basis for resistance to staurosporine-induced apoptosis in PC-3 cells.

We have reported previously that among human prostate cancer cell lines LNCaP but not PC-3 cells undergo apoptosis after treatment with the protein kinase inhibitor staurosporine (STS). We have now further investigated this model to uncover the molecular mechanism causing resistance to STS-induced apoptosis in PC-3 cells. S-100 lysates of both cell lines showed biochemical changes typical of apoptosis after the addition of cytochrome c and dATP, suggesting that the postmitochondrial phase of apoptosis was intact. Upon addition of STS, the proapoptotic molecules Bax and Bad became predominantly mitochondrial in both cell lines. This, in turn, was followed by loss of mitochondrial transmembrane potential, translocation of cytochrome c to the cytosol, activation of caspase-9, -3, and -7, and cleavage of the apoptotic targets, DNA fragmentation factor and poly(ADP-ribose) polymerase, in LNCaP but not in PC-3 cells. Components of the mitochondrial permeability transition pore, adenine nucleotide transporter and voltage-dependent anion channel, were normally expressed in the correct subcellular fraction of both cell lines. Overexpression of the proapoptotic proteins Bax and Bad, fused to a green fluorescent protein but not of green fluorescent protein alone, induced apoptosis in >80% of PC-3 cells. These experiments suggested that a factor protecting the mitochondria of PC-3 cells mediates resistance to STS-induced apoptosis. A wide search among the antiapoptotic Bcl-2 family members was performed, and Bcl-X(L) was found to be overexpressed in PC-3 cells. Experiments down-regulating Bcl-X(L) expression by using the tyrosine kinase inhibitor genistein, sodium butyrate, or an antisense Bcl-X(L) oligonucleotide restored sensitivity to apoptosis in PC-3 cells. Thus, Bcl-X(L) overexpression is one of the mediators of resistance to STS-induced apoptosis in the prostate cancer cell line PC-3.

Smokeless tobacco extracts modulate keratinocyte and fibroblast growth in organotypic culture.

Smokeless tobacco is associated with pathologic alterations of the oral mucosa, yet its direct effects on human keratinocytes and fibroblasts in stratified squamous epithelium are not well-understood. We hypothesized that smokeless tobacco could modulate the growth of keratinocytes and fibroblasts in an in vivo-like, organotypic tissue model. To test this, we exposed organotypic cultures for 3 days to smokeless tobacco aqueous extracts and determined the changes in morphology and proliferation of human keratinocytes and fibroblasts. All smokeless tobaccos stimulated keratinocyte proliferation at low doses (0.25% w/v) and suppressed growth at higher doses (> 0.5% w/v). In contrast, smokeless tobacco extracts promoted fibroblast growth at all concentrations without inducing fibroblast turnover. Fibroblasts and keratinocytes, therefore, were differentially affected by smokeless tobacco extracts in an organotypic tissue model, suggesting incipient changes that may occur in vivo.