Dual EGFR and mTOR targeting in squamous cell carcinoma models, and development of early markers of efficacy

The epidermal growth factor receptor (EGFR) is a validated target in squamous cell carcinoma (SCC) of the head and neck. Most patients, however, do not respond or develop resistance to this agent. Mammalian target of rapamycin (mTOR) is involved in the pathogenesis of SCC of the head and neck (SCCHN). This study aimed to determine if targeting mTOR in combination with EGFR is effective in SCC, and to develop early pharmacodynamic markers of efficacy. Two SCC cell lines, one resistant (HEP2) and one of intermediate susceptibility (Detroit 562) to EGFR inhibitors, were xenografted in vivo and treated with an mTOR inhibitor (temsirolimus), an EGFR inhibitor (erlotinib) or a combination of both. Temsirolimus exerted superior growth arrest in both cell lines than erlotinib. The combined treatment resulted in synergistic antitumor effects in the Detroit 562 cell line. Immunohistochemical assessment of pharmacodynamic effects in fine-needle aspiration (FNA) biopsies early after treatment using phospho MAPK, Phospho-P70 and Ki67 as end points demonstrated pathway abrogation in the Detroit 562 tumours treated with the combination, the only group where regressions were seen. In conclusion, an mTOR inhibitor showed antitumor activity in EGFR-resistant SCC cell lines. Marked antitumor effects were associated with dual pathway inhibition, which were detected by early FNA biopsies.

Subthalamic nucleus stimulation modulates afferent inhibition in Parkinson disease

BACKGROUND

Peripheral sensory stimulation at the wrist inhibits the motor cortex as measured by transcranial magnetic stimulation at interstimulus intervals of approximately 20 ms (short latency afferent inhibition [SAI]) and 200 ms (long latency afferent inhibition [LAI]). Previous studies suggested that reduced SAI in Parkinson disease (PD) reflects adverse effect of dopaminergic medications and reduced LAI may be related to nondopaminergic manifestations of PD. We hypothesize that subthalamic nucleus (STN) deep brain stimulation (DBS) may correct these deficiencies.

METHODS

We studied the effects of STN DBS on SAI and LAI in seven PD patients and age-matched controls. PD patients were studied in an off medication followed by an on medication session, with the stimulator switched on or off in random order in each session.

RESULTS

In the on medication session, SAI was reduced in the stimulator off condition and was restored by STN DBS. LAI was partially normalized by STN DBS in the medication on condition.

CONCLUSIONS

Subthalamic nucleus (STN) stimulation improves short latency afferent inhibition, suggesting that it could normalize pathways that are adversely affected by dopaminergic medications. The effect of STN stimulation on long latency afferent inhibition suggests that it may influence nondopaminergic pathways involved in sensorimotor integration.

Trophoblast?Macrophage Interactions: a Regulatory Network for the Protection of Pregnancy

PROBLEM

Macrophages are one of the first immune cells observed at the implantation site. Their presence has been explained as the result of an immune response toward paternal antigens. The mechanisms regulating monocyte migration and differentiation at the implantation site are largely unknown. In the present study, we demonstrate that trophoblast cells regulate monocyte migration and differentiation. We propose that trophoblast cells 'educate' monocytes/macrophages to create an adequate environment that promote trophoblast survival.

METHOD OF STUDY

CD14(+) monocytes were isolated from peripheral blood using magnetic beads. Co-culture experiments were conducted using a two-chamber system. Monocytes were stimulated with lipopolysaccharide (LPS) and cytokine levels were determined using multiplex cytokine detecting assay.

RESULTS

Trophoblast cells increase monocyte migration and induce a significant increase in the secretion and production of the pro-inflammatory cytokines [interleukin-6 (IL-6), IL-8, tumor necrosis factor-alpha] and chemokines (growth-related oncogen-alpha, monocyte chemoattractant protein-1, macrophage inflammatory protein-1beta, RANTES). Furthermore, the response of monocytes to LPS was different in monocytes pre-exposed to trophoblast cells.

CONCLUSION

The results of this study suggest that trophoblast cells are able to recruit and successfully educate monocytes to produce and secrete a pro-inflammatory cytokine and chemokine profile supporting its growth and survival. Furthermore we demonstrate that trophoblast cells can modulate monocytes response to bacterial stimuli.

Effect of over-expression of neuropathy target esterase on mammalian cell proliferation

Neuropathy target esterase (NTE), the human homologue of a protein required for brain development in Drosophila, is expressed primarily in neural cells but is also detected in non-neural cells. Although NTE has been proposed to play a role in neurite outgrowth and process elongation during neurodifferentiation, the function of NTE has not been defined in neural cells. In this study we have investigated the possible role of NTE in neuroblastoma cells and non-neural cells using an over-expression strategy. Over-expression of NTE in human neuroblastoma SH-SY5Y cells and monkey kidney COS7 cells led to an accumulation of NTE on the cytoplasmic surface of the endoplasmic reticulum and inhibition of cell proliferation. In particular, high levels of NTE arrested COS7 cells at G2/M stage yet was not associated with arrest at a particular phase of the cell cycle in SH-SY5Y cells. Moreover, over-expression of NTE did not induce apoptosis in two kinds of cell lines as assessed by flow cytometry. These results suggest that the role of NTE over-expression in cell proliferation is associated with different mechanisms in different cells.

Depot-specific messenger RNA expression of 11β-hydroxysteroid dehydrogenase type 1 and leptin in adipose tissue of children and adults

OBJECTIVE

To compare expression of messenger RNA (mRNA) coding for the cortisol regenerating enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), and the adipocytokines leptin and resistin in paired biopsies of subcutaneous adipose tissue (SC) and omental adipose tissue (OM) from children.

DESIGN

Paired biopsies (SC and OM) were obtained from 54 children (age 0.17-16 years, body mass index (BMI) 12.5-28.3 kg/m(2), BMI standard deviation score (SDS) -2.5-4.5) and 16 adults (age 27-79 years, BMI 19-46 kg/m(2)) undergoing open abdominal surgery. mRNA levels of 11beta-HSD1, leptin and resistin were measured using quantitative real-time polymerase chain reaction (PCR).

RESULTS

11beta-HSD1 mRNA level was higher in OM than in SC (P<0.05), whereas leptin mRNA was higher in SC than in OM (P<0.001). There was no difference in the resistin mRNA level between SC and OM. These results were consistent in children and adults. In children, 11beta-HSD1 mRNA in SC was positively associated with BMI SDS (P<0.05), whereas in OM it was positively associated with age (P<0.05). The association between 11beta-HSD1 expression and age remained significant after adjustment for BMI SDS and gender. Leptin mRNA was positively associated with BMI SDS (SC: P<0.001, OM: P<0.001) but not with age in children. In multiple regression analyses, including anthropometric variables and age, BMI SDS was independently associated with mRNA levels of 11beta-HSD1 (P<0.05) and leptin (P<0.001) in SC. When normal weight and overweight children were analyzed separately, 11beta-HSD1 mRNA levels were positively associated with leptin in OM in the overweight group (P<0.05).

CONCLUSION

There are depot-specific differences in mRNA levels of 11beta-HSD1 and leptin in children and adults. The positive association of 11beta-HSD1 mRNA in OM with age may reflect a causal role in visceral fat accumulation during growth. Increasing 11beta-HSD1 and leptin mRNA in SC with increasing BMI SDS could suggest that the risk of metabolic consequences of obesity may be established early in life.

Reduced semen quality in chronic prostatitis patients that induce the release of apoptotic protein Omi/HtrA2 from spermatozoa

The relationship between chronic prostatitis and fertility has been disputed for many years. Several groups have shown infection and autoimmune response against prostate antigens could have a deleterious effect on semen quality and fertility. This study was conducted to test the hypothesis that Omi/HtrA2-induced apoptosis in chronic prostatitis could be a mechanism underlying the observed clinical benefit. The Omi/HtrA2 serine protease is a nuclear-encoded mitochondrial protein, which can be released from mitochondria into the cytosol after apoptosis stimuli, inducing apoptosis in caspase-dependent and independent manners. Forty-one patients diagnosed as suffering from chronic prostatitis were included. Healthy normal individuals were included as controls. Human spermatozoa in the semen were purified by Percoll-gradient technique to separate the seminal plasma and other round cells. Measurements for sperm concentration, motility, morphology, proinflammatory cytokines, Omi/HtrA2 mRNA and protein levels in spermatozoa of chronic protatitis patients, were performed accordingly. Significantly increased levels of proinflammatory cytokines were detected in seminal plasma from these prostatitis patients. Omi/HtrA2 mRNA and protein levels were significantly higher in prostatitis men than in normal men. This study shows that chronic prostatitis patients present important alterations in their semen quality parameters, Omi/HtrA2 mRNA and protein levels of spermatozoa. We speculate that the inflammatory process involved may affect male fertility by release of proapoptotic protein Omi/HtrA2.

Burkholderia cenocepacia ZmpB is a broad-specificity zinc metalloprotease involved in virulence

In previous studies we characterized the Burkholderia cenocepacia ZmpA zinc metalloprotease. In this study, we determined that B. cenocepacia has an additional metalloprotease, which we designated ZmpB. The zmpB gene is present in the same species as zmpA and was detected in B. cepacia, B. cenocepacia, B. stabilis, B. ambifaria, and B. pyrrocinia but was absent from B. multivorans, B. vietnamiensis, B. dolosa, and B. anthina. The zmpB gene was expressed, and ZmpB was purified from Escherichia coli by using the pPROEXHTa His(6) Tag expression system. ZmpB has a predicted preproenzyme structure typical of thermolysin-like proteases and is distantly related to Bacillus cereus bacillolysin. ZmpB was expressed as a 63-kDa preproenzyme precursor that was autocatalytically cleaved into mature ZmpB (35 kDa) and a 27-kDa prepropeptide. EDTA, 1,10-phenanthroline, and Zn(2+) cations inhibited ZmpB enzyme activity, indicating that it is a metalloprotease. ZmpB had proteolytic activity against alpha-1 proteinase inhibitor, alpha(2)-macrogobulin, type IV collagen, fibronectin, lactoferrin, transferrin, and immunoglobulins. B. cenocepacia zmpB and zmpA zmpB mutants had no proteolytic activity against casein and were less virulent in a rat agar bead chronic infection model, indicating that zmpB is involved in B. cenocepacia virulence. Expression of zmpB was regulated by both the CepIR and CciIR quorum-sensing systems.

Effects of a Single Nucleotide Polymorphism on the Expression of Human Tumor Necrosis Factor-alpha

Tumor necrosis factor (TNF)-alpha plays a prominent role in inflammations and is a proinflammatory cytokine that has been implicated in the pathogenesis of autoimmune and infectious diseases. Recent association studies have found that the TNF-alpha-857T allele was associated with several disorders. Here we demonstrate, with reporter genes under the control of the two allelic TNF-alpha promoters, that the minor allele -857T is a much stronger transcriptional activator than the major allele -857C in RAW264.7 cell line in response to lipopolysaccharide stimulation. However, the result was not consistent in HeLa cell line. Furthermore, for the quantitative analysis of TNF-alpha synthesis between the -857C/C genotype from healthy subjects and the -857C/T genotype from AS patients, the quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed separately. There was no significant difference between the two groups at the level of mRNA and protein. These results show that this polymorphism may have a direct effect on TNF-alpha regulation in a tissue-specific manner, and apart from the polymorphism at -857 in the TNF-alpha promoter, there may be other factors affecting the expression of TNF-alpha.

Differentiating sex chromosomes of the dioecious Spinacia oleracea L. (spinach) by FISH of 45S rDNA

Spinacia oleracea L. (spinach) is a dioecious species with both male and female plants having 2n = 2x = 12 chromosomes, consisting of two large metacentrics, two long subtelocentrics, two short subtelocentrics, two acrocentrics, and four submetacentrics. The location of 45S rDNA was investigated on metaphase chromosomes using fluorescence in situ hybridization (FISH). The numbers of 45S rDNA foci in diploid sets of chromosomes from females was six and from males was five. All the fluorescent foci lay in secondary constrictions and the satellites. Our results indicate that an XY-type sex chromosome system could be present in spinach where the Y chromosome lacks a 45S RNA focus.

Novel method for predicting chemoresistance to paclitaxel in epithelial ovarian cancer patients

15007

Background: No available test exists to guide the selection of effective chemotherapeutic regimen in recurrent ovarian cancer. Preliminary studies in our lab have identified a protein, MyD88, a major component in the inflammatory pathway, to be highly expressed in epithelial ovarian cancer cells that exhibit primary or acquired Paclitaxel chemoresistance. The objective of this study was to develop a sensitive approach that can detect expression of MyD88 in ovarian cancer tissue. We report the development of a test based on Laser capture microdissection that allows detection of MyD88 in a 6000 cell sample. Methods: Tumor tissue was obtained at surgery from epithelial ovarian cancer patients and snap-frozen in liquid nitrogen. Eight micron sections were prepared on polyethylene covered glass slides and tumor cells were dissected with a Laser capture microdissection system. Protein expression was detected by Western blot analysis. Results: Protein expression was detected by Western blot analysis in 1000 microdissected cells. An inverse correlation was observed between MyD88 expression in tumor cells and clinical response to Paclitaxel. Furthermore, this method allows the isolation of CD-45 positive cells from the tumor and analysis of their protein expression. Conclusions: We describe for the first time a method that will allow us to predict chemoresistance. Laser capture microdissection is a powerful technique that can be used to study the protein profile of each of the cellular components present in the tumor microenvironment. This technique will facilitate our understanding of the proteins necessary for tumor growth and may help to identify novel markers or potential protein targets.

No significant financial relationships to disclose.