Malignant Pleural Mesothelioma and Radiotherapy: Lung Toxicity Results of an Interim Analysis in Prospective Pilot Trial

PURPOSE/OBJECTIVE(S)

Malignant Pleural Mesothelioma (MPM) is a rare but aggressive intrathoracic malignancy with an overall poor prognosis. Neoadjuvant chemotherapy, surgery and then radiotherapy is the standard of care in early-stage disease. Our study aim is to evaluate the feasibility and toxicity of the novel adjuvant RT in accelerated hypofractionation. We report the lung toxicity preliminary results of the first patients entreated.

MATERIALS/METHODS

Starting in 2017, 29 MPM patients were enrolled in the trial (IRST trial 163). All patients were treated with accelerated hypofractionated radiotherapy using a helical 3-D CRT and IMRT system and intensity-modulated arc therapy. We conducted a prospective mono-institutional clinical trial enrolling cyto-histological proven, MPM patients. The major exclusion criteria were: previous thorax radiotherapy, contralateral mediastinum involvement (N3) and/or M1, interstitial pneumopathy, active pneumonitis, and fissural disease. The prescription dose was 30 Gy in five daily fractions, while an inhomogeneous dose escalation to 40 Gy was prescribed based solely upon the presence of gross residual tumor. All patients were treated in a 3-D CRT and IMRT system. Patients underwent functional lung study before to start radiotherapy treatment, 2 months and 6 months after the end of the treatment. The organs at risk dose-volume histograms were converted to a 2-Gy equivalent dose, and we closely adhered to the dose constraints of the literature data. We in particular analyzed lung toxicity of the first 20 patients.

RESULTS

No G3/G4 lung toxicity was found. We reported 65.0% G1 pneumonitis and 10% G2 as acute lung toxicity. The majority of the G1 patients had only mild symptoms and pneumonitis was described only for radiologic features with no need for medical therapy. Other respiratory toxicities were G1-G2 cough in 50% of the patients; G1 dyspnea occurred in 65% of the patients and G2 in the 15%. The total lung mean dose was 18 Gy (range 13 Gy-23 Gy), and the contralateral lung mean dose was 2 Gy (range 1 Gy-2 Gy). The median value of Forced Expired Volume in one second (FEV1) recorded was 75.5% (range: 46%-137%) before the treatment was started, the median value of Forced Vital Capacity (FVC) at baseline was 74 (range 46-123) with progressive decreasing values through time. DLCO has also been reported with a progressive decrease over time after radiotherapy treatment. No case of respiratory failure was reported after treatment.

CONCLUSION

Treatment of the intact lung with pleural intensity-modulated arc irradiation is a novel treatment strategy that appears to be safe, feasible, and without a high grade of lung toxicity. More investigations are mandatory. The protocol is ongoing.

Hyperbaric Oxygen Therapy plus Hypofractionated Stereotactic Radiotherapy in Recurrent Glioblastoma

PURPOSE/OBJECTIVE(S)

Hypoxia is thought to play a role in tumor development, angiogenesis and growth, and resistance to chemotherapy, antiangiogenic therapy and radiotherapy (RT) in a large number of human cancers. Brain tumors, especially highly aggressive GBM with its necrotic tissue, are more likely to be affected by hypoxia. The median partial pressure of oxygen (PO2) of high-grade gliomas in patients under anesthesia was approximately 5-7 mmHg, with a significant proportion of PO2 values <2.5 mmHg. The radiosensitivity of brain tumors could potentially be increased by performing hyperbaric oxygenation (HBO) before the RT session. We propose an innovative approach to improve the efficacy of accelerated hypofractionated Stereotactic Radiotherapy (HSRT) after HBO (HBO-RT) for the treatment of recurrent HGG (rHGG). The primary objective of this study is to evaluate the disease control rate (DCR) at 3 months. The secondary Objectives are: - Safety assessment (acute and late toxicity). - Overall Survival (OS), - Progression Free Survival (PFS).

MATERIALS/METHODS

We enrolled 14 patients (aged >18 years) with rHGG detected using MRI. A total dose of 15-25 Gy was administered in daily 5-Gy fractions for 3-5 consecutive days after daily HBO.

RESULTS

Median follow-up from re-irradiation was 22.8 months (range: 2.0-24.2 months). The disease control rate 3-months after HBO-RT was 50% (23.0-76.9). Six- and 12-month Progression-free survival was 35.7% (95% CI: 13-59.4) and 10.7% (95% CI: 0.8-35.4), respectively. Median overall survival of HBO-RT was 10.7 months (95% CI: 6.6-24.2). No acute or late neurologic toxicity >grade (G)2 was observed.

CONCLUSION

HSRT combined to HBO seems effective and safe in the treatment of rHGG.

MicroRNAs Present in Malignant Pleural Fluid Increase the Migration of Normal Mesothelial Cells In Vitro and May Help Discriminate between Benign and Malignant Effusions

The sensitivity of pleural fluid (PF) analyses for the diagnosis of malignant pleural effusions (MPEs) is low to moderate. Knowledge about the pathobiology and molecular characteristics of this condition is limited. In this study, the crosstalk between stromal cells and tumor cells was investigated in vitro in order to reveal factors that are present in PF which can mediate MPE formation and aid in discriminating between benign and malignant etiologies. Eighteen PF samples, in different proportions, were exposed in vitro to mesothelial MeT-5A cells to determine the biological effects on these cells. Treatment of normal mesothelial MeT-5A cells with malignant PF increased cell viability, proliferation, and migration, and activated different survival-related signaling pathways. We identified differentially expressed miRNAs in PF samples that could be responsible for these changes. Consistently, bioinformatics analysis revealed an enrichment of the discovered miRNAs in migration-related processes. Notably, the abundance of three miRNAs (miR-141-3p, miR-203a-3, and miR-200c-3p) correctly classified MPEs with false-negative cytological examination results, indicating the potential of these molecules for improving diagnosis. Malignant PF produces phenotypic and functional changes in normal mesothelial cells. These changes are partly mediated by certain miRNAs, which, in turn, could serve to differentiate malignant from benign effusions.

Applications of CRISPR Technology to Breast Cancer and Triple Negative Breast Cancer Research

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has transformed oncology research in many ways. Breast cancer is the most prevalent malignancy globally and triple negative breast cancer (TNBC) is one of the most aggressive subtypes with numerous challenges still to be faced. In this work, we have explained what CRISPR consists of and listed its applications in breast cancer while focusing on TNBC research. These are disease modelling, the search for novel genes involved in tumour progression, sensitivity to drugs and immunotherapy response, tumour fitness, diagnosis, and treatment. Additionally, we have listed the current delivery methods employed for the delivery of CRISPR systems in vivo. Lastly, we have highlighted the limitations that CRISPR technology is subject to and the future directions that we envisage. Overall, we have provided a round summary of the aspects concerning CRISPR in breast cancer/TNBC research.

PLA2G12A as a Novel Biomarker for Colorectal Cancer with Prognostic Relevance

Metastasis is the leading cause of colorectal cancer (CRC)-related deaths. Therefore, the identification of accurate biomarkers predictive of metastasis is needed to better stratify high-risk patients to provide preferred management and reduce mortality. In this study, we identified 13 new genes that modified circulating tumor cell numbers using a genome-wide genetic screen in a whole animal CRC model. Candidate genes were subsequently evaluated at the gene expression level in both an internal human CRC cohort of 153 patients and an independent cohort from the TCGA including 592 patients. Interestingly, the expression of one candidate, PLA2G12A, significantly correlated with both the time to recurrence and overall survival in our CRC cohort, with its low expression being an indicator of a poor clinical outcome. By examining the TCGA cohort, we also found that low expression of PLA2G12A was significantly enriched in epithelial-mesenchymal transition signatures. Finally, the candidate functionality was validated in vitro using three different colon cancer cell lines, revealing that PLA2G12A deficiency increases cell proliferation, migration, and invasion. Overall, our study identifies PLA2G12A as a prognostic biomarker of early-stage CRC, providing evidence that its deficiency promotes tumor growth and dissemination.

RASER-FISH: non-denaturing fluorescence in situ hybridization for preservation of three-dimensional interphase chromatin structure

DNA fluorescence in situ hybridization (FISH) has been a central technique in advancing our understanding of how chromatin is organized within the nucleus. With the increasing resolution offered by super-resolution microscopy, the optimal maintenance of chromatin structure within the nucleus is essential for accuracy in measurements and interpretation of data. However, standard 3D-FISH requires potentially destructive heat denaturation in the presence of chaotropic agents such as formamide to allow access to the DNA strands for labeled FISH probes. To avoid the need to heat-denature, we developed Resolution After Single-strand Exonuclease Resection (RASER)-FISH, which uses exonuclease digestion to generate single-stranded target DNA for efficient probe binding over a 2 d process. Furthermore, RASER-FISH is easily combined with immunostaining of nuclear proteins or the detection of RNAs. Here, we provide detailed procedures for RASER-FISH in mammalian cultured cells to detect single loci, chromatin tracks and topologically associating domains with conventional and super-resolution 3D structured illumination microscopy. Moreover, we provide a validation and characterization of our method, demonstrating excellent preservation of chromatin structure and nuclear integrity, together with improved hybridization efficiency, compared with classic 3D-FISH protocols.

Are Transcription Factors Plausible Oncotargets for Triple Negative Breast Cancers?

Simple Summary

Triple negative breast cancer is a type of breast cancer that does not have a selective and effective therapy. It is known that this cancer possesses high abundance of certain proteins called transcription factors, which are essential for their growth. However, inhibiting transcription factors is very difficult with common therapeutics due to their inaccessibility inside the cell and their molecular structure. In this work, we identified the most important transcription factors for the growth of triple negative breast cancers, and that can predict worse clinical outcome. Moreover, we described different strategies that have been utilised to inhibit them. A successful inhibition of these transcription factors could reduce the mortality and convalescence associated with triple negative breast cancers.

Abstract

Breast cancer (BC) is the most diagnosed cancer worldwide and one of the main causes of cancer deaths. BC is a heterogeneous disease composed of different BC intrinsic subtypes such as triple-negative BC (TNBC), which is one of the most aggressive subtypes and which lacks a targeted therapy. Recent comprehensive analyses across cell types and cancer types have outlined a vast network of protein–protein associations between transcription factors (TFs). Not surprisingly, protein–protein networks central to oncogenesis and disease progression are highly altered during TNBC pathogenesis and are responsible for the activation of oncogenic programs, such as uncontrollable proliferation, epithelial-to-mesenchymal transition (EMT) and stemness. From the therapeutic viewpoint, inhibiting the interactions between TFs represents a very significant challenge, as the contact surfaces of TFs are relatively large and featureless. However, promising tools have emerged to offer a solution to the targeting problem. At the clinical level, some TF possess diagnostic and prognostic value in TNBC. In this review, we outline the recent advances in TFs relevant to TNBC growth and progression. Moreover, we highlight different targeting approaches to inhibit these TFs. Furthermore, the validity of such TFs as clinical biomarkers has been explored. Finally, we discuss how research is likely to evolve in the field.

Microenvironmental Reactive Oxygen Species in Colorectal Cancer: Involved Processes and Therapeutic Opportunities

Colorectal cancer (CRC) is the fourth most common cause of cancer deaths worldwide. Although screening programs have reduced mortality rates, there is a need for research focused on finding the main factors that lead primary CRC to progress and metastasize. During tumor progression, malignant cells modify their habitat, corrupting or transforming cells of different origins and creating the tumor microenvironment (TME). Cells forming the TME like macrophages, neutrophils, and fibroblasts generate reactive oxygen species (ROS) that modify the cancer niche. The effects of ROS in cancer are very diverse: they promote cellular proliferation, epithelial-to-mesenchymal transition (EMT), evasion of cell death programs, migration, and angiogenesis. Due to the multifaceted role of ROS in cancer cell survival and function, ROS-modulating agents such as antioxidants or pro-oxidants could have therapeutic potential in cancer prevention and/or as a complement to systemic treatments. In this review, we will examine the main ROS producer cells and their effects on cancer progression and metastasis. Furthermore, we will enumerate the latest clinical trials where pro-oxidants and antioxidants have therapeutic uses in CRC.

Stress granules display bistable dynamics modulated by Cdk

Stress granules (SGs) are conserved biomolecular condensates that originate in response to many stress conditions. These membraneless organelles contain nontranslating mRNAs and a diverse subproteome, but our knowledge of their regulation and functional relevance is still incipient. Here, we describe a mutual-inhibition interplay between SGs and Cdc28, the budding yeast Cdk. Among Cdc28 interactors acting as negative modulators of Start, we have identified Whi8, an RNA-binding protein that localizes to SGs and recruits the mRNA of CLN3, the most upstream G1 cyclin, for efficient translation inhibition and Cdk inactivation under stress. However, Whi8 also contributes to recruiting Cdc28 to SGs, where it acts to promote their dissolution. As predicted by a mutual-inhibition framework, the SG constitutes a bistable system that is modulated by Cdk. Since mammalian cells display a homologous mechanism, we propose that the opposing functions of specific mRNA-binding proteins and Cdk’s subjugate SG dynamics to a conserved hysteretic switch.

Prognostic Factors Involved in the Epithelial-Mesenchymal Transition Process in Colorectal Cancer Have a Preponderant Role in Oxidative Stress: A Systematic Review and Meta-Analysis

Epithelial-to-mesenchymal transition (EMT) is one of the most accepted mechanisms leading to metastasis, which is responsible for most of the cancer-related deaths. In order to identify EMT-related biomarkers able to predict clinical outcomes in colorectal cancer (CRC), a systematic review and meta-analysis of prognostic factors associated to overall survival (OS) and progression free survival (PFS) was conducted. The systematic literature search included studies from June 2014 to June 2019 available at PubMed and Scopus databases. Meta-analysis was performed for those markers appearing in minimum three works with a total number of 8656 participants. The rest were enlisted and subjected to functional enrichment. We identified nine clinical biomarkers and 73 EMT-related molecular biomarkers associated to OS and/or PFS in CRC. The significant enrichment of biomarkers found involved in cellular oxidoreductase activity suggests that ROS generation plays an active role in the EMT process. Clinical practice needs new biomarkers with a reliable prognostic value able to predict clinical outcomes in CRC. Our integrative work supports the role of oxidative stress in tumorigenesis and EMT progress highlighting the importance of deciphering this specific mechanism to get a better understanding of metastasis.

Determinants of Sensitivity to Radiotherapy in Endometrial Cancer

Radiotherapy is one of the cornerstone treatments for endometrial cancer and has successfully diminished the risk of local recurrences after surgery. However, a considerable percentage of patients suffers tumor relapse due to radioresistance mechanisms. Knowledge about the molecular determinants that confer radioresistance or radiosensitivity in endometrial cancer is still partial, as opposed to other cancers. In this review, we have highlighted different central cellular signaling pathways and processes that are known to modulate response to radiotherapy in endometrial cancer such as PI3K/AKT, MAPK and NF-κB pathways, growth factor receptor signaling, DNA damage repair mechanisms and the immune system. Moreover, we have listed different clinical trials employing targeted therapies against some of the aforementioned signaling pathways and members with radiotherapy. Finally, we have identified the latest advances in radiotherapy that have started being utilized in endometrial cancer, which include modern radiotherapy and radiogenomics. New molecular and genetic studies in association with the analysis of radiation responses in endometrial cancer will assist clinicians in taking suitable decisions for each individual patient and pave the path for personalized radiotherapy.

Trans-oral robotic surgery for the management of oropharyngeal carcinomas: a 9-year institutional experience

Trans-oral robotic surgery (TORS) has changed surgical management of patients with oropharyngeal squamous cell carcinomas (OPSCC). In this study we present surgical and oncologic outcomes of patients with oropharyngeal squamous cell carcinomas, treated using TORS, with and without an adjuvant therapy. Sixty patients with oropharyngeal squamous cell carcinomas treated with TORS between January 2008 and December 2017 have been retrospectively evaluated considering clinicopathologic features, disease characteristics, adjuvant treatments and oncological outcomes. TORS was performed for OPSCC to the base of tongue in 41.7%, tonsils in 46.7%, soft palate and posterior pharyngeal wall in 3.3% and 5%, respectively. Neck dissection was performed in 43.3% of patients. Management strategies included surgery alone in 30%, TORS and adjuvant radiotherapy in 33.3%, and TORS plus adjuvant chemotherapy in 36.7%. The 5-year overall survival of the total group was 77.6%, the 5-year disease-free survival rate was 85.2%, and the 5-year local recurrence-free survival rate was 90.6%. Finally, in selected patients TORS appears to yield similar oncologic outcomes and functional outcomes to traditional techniques and non-operative treatment with a possible benefit on long-term quality of life. The future offers exciting opportunities to combine TORS and radiotherapy in unique ways. However, further research is urgently needed to clarify the indications for adjuvant therapy following TORS resections.

Competition in the chaperone-client network subordinates cell-cycle entry to growth and stress

The precise coordination of growth and proliferation has a universal prevalence in cell homeostasis. As a prominent property, cell size is modulated by the coordination between these processes in bacterial, yeast, and mammalian cells, but the underlying molecular mechanisms are largely unknown. Here, we show that multifunctional chaperone systems play a concerted and limiting role in cell-cycle entry, specifically driving nuclear accumulation of the G1 Cdk-cyclin complex. Based on these findings, we establish and test a molecular competition model that recapitulates cell-cycle-entry dependence on growth rate. As key predictions at a single-cell level, we show that availability of the Ydj1 chaperone and nuclear accumulation of the G1 cyclin Cln3 are inversely dependent on growth rate and readily respond to changes in protein synthesis and stress conditions that alter protein folding requirements. Thus, chaperone workload would subordinate Start to the biosynthetic machinery and dynamically adjust proliferation to the growth potential of the cell.

Centromeric signaling proteins boost G1 cyclin degradation and modulate cell size in budding yeast

Cell size scales with ploidy in a great range of eukaryotes, but the underlying mechanisms remain unknown. Using various orthogonal single-cell approaches, we show that cell size increases linearly with centromere (CEN) copy number in budding yeast. This effect is due to a G1 delay mediated by increased degradation of Cln3, the most upstream G1 cyclin acting at Start, and specific centromeric signaling proteins, namely Mad3 and Bub3. Mad3 binds both Cln3 and Cdc4, the adaptor component of the Skp1/Cul1/F-box (SCF) complex that targets Cln3 for degradation, these interactions being essential for the CEN-dosage dependent effects on cell size. Our results reveal a pathway that modulates cell size as a function of CEN number, and we speculate that, in cooperation with other CEN-independent mechanisms, it could assist the cell to attain efficient mass/ploidy ratios.

Cdc48/p97 segregase is modulated by cyclin-dependent kinase to determine cyclin fate during G1 progression

Cells sense myriad signals during G1, and a rapid response to prevent cell cycle entry is of crucial importance for proper development and adaptation. Cln3, the most upstream G1 cyclin in budding yeast, is an extremely short-lived protein subject to ubiquitination and proteasomal degradation. On the other hand, nuclear accumulation of Cln3 depends on chaperones that are also important for its degradation. However, how these processes are intertwined to control G1-cyclin fate is not well understood. Here, we show that Cln3 undergoes a challenging ubiquitination step required for both degradation and full activation. Segregase Cdc48/p97 prevents degradation of ubiquitinated Cln3, and concurrently stimulates its ER release and nuclear accumulation to trigger Start. Cdc48/p97 phosphorylation at conserved Cdk-target sites is important for recruitment of specific cofactors and, in both yeast and mammalian cells, to attain proper G1-cyclin levels and activity. Cdk-dependent modulation of Cdc48 would subjugate G1 cyclins to fast and reversible state switching, thus arresting cells promptly in G1 at developmental or environmental checkpoints, but also resuming G1 progression immediately after proliferative signals reappear.

High dose irradiation after pleurectomy/decortication or biopsy for pleural mesothelioma treatment

PURPOSE

The role played by radiation therapy after pleurectomy/decortication or surgical biopsy in malignant pleural mesothelioma is uncertain. We treated patients with accelerated hypofractionated radiotherapy using helical tomotherapy and intensity-modulated arc therapy in an attempt to keep lung toxicity to a minimum. The present study reports the feasibility and toxicity of this approach.

MATERIAL AND METHODS

Between 2008 and 2012, 36 patients with malignant pleural mesothelioma underwent accelerated hypofractionated radiotherapy to the hemithorax after pleurectomy/decortication (19 patients) or biopsy (17 patients). The prescription dose was 25Gy in five fractions over 5 consecutive days.

RESULTS

We observed three patients with G3 pneumonitis, five cases of grade 2 dyspnea and six cases of grade 2 cough. The median follow-up was 37 months (range: 3-54 months). The median overall survival for patients who underwent pleurectomy/decortication followed by radiotherapy was 21.6 months [95% confidence interval (95% CI): 15.5-24.1] compared to 19.4 months for patients not submitted to surgery.

CONCLUSION

Treatment of intact lung with pleural intensity-modulated arc irradiation in malignant pleural mesothelioma patients with malignant pleural mesothelioma proved safe and feasible, with an acceptable rate of pneumonitis. Survival rates were encouraging for both biopsy-only and pleurectomy/decortication groups. We are currently conducting a phase II dose escalation trial in a similar patient setting to prospectively evaluate the impact of radiotherapy on toxicity, disease-free survival and overall survival.

Lack of vitamin D receptor causes stress-induced premature senescence in vascular smooth muscle cells through enhanced local angiotensin-II signals

OBJECTIVES

The inhibition of the renal renin-angiotensin system by the active form of vitamin D contributes to the cardiovascular health benefits of a normal vitamin D status. Local production of angiotensin-II in the vascular wall is a potent mediator of oxidative stress, prompting premature senescence. Herein, our objective was to examine the impact of defective vitamin D signalling on local angiotensin-II levels and arterial health.

METHODS

Primary cultures of aortic vascular smooth muscle cells (VSMC) from wild-type and vitamin D receptor-knockout (VDRKO) mice were used for the assessment of cell growth, angiotensin-II and superoxide anion production and expression levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2). The in vitro findings were confirmed histologically in aortas from wild-type and VDRKO mice.

RESULTS

VSMC from VDRKO mice produced more angiotensin-II in culture, and elicited higher levels of cathepsin D, an enzyme with renin-like activity, and angiotensin-II type 1 receptor, than wild-type mice. Accordingly, VDRKO VSMC showed higher intracellular superoxide anion production, which could be suppressed by cathepsin D, angiotensin-II type 1 receptor or NADPH oxidase antagonists. VDRKO cells presented higher levels of p57(Kip2), impaired proliferation and premature senescence, all of them blunted upon inhibition of angiotensin-II signalling. In vivo studies confirmed higher levels of cathepsin D, angiotensin-II type 1 receptor and p57(Kip2) in aortas from VDRKO mice.

CONCLUSION

The beneficial effects of active vitamin D in vascular health could be a result of the attenuation of local production of angiotensin-II and downstream free radicals, thus preventing the premature senescence of VSMC.

A Whi7-anchored loop controls the G1 Cdk-cyclin complex at start

Cells commit to a new cell cycle at Start by activation of the G1 Cdk-cyclin complex which, in turn, triggers a genome-wide transcriptional wave that executes the G1/S transition. In budding yeast, the Cdc28-Cln3 complex is regulated by an ER-retention mechanism that is important for proper cell size control. We have isolated small-cell-size CDC28 mutants showing impaired retention at the ER and premature accumulation of the Cln3 cyclin in the nucleus. The differential interactome of a quintuple Cdc28(wee) mutant pinpointed Whi7, a Whi5 paralog targeted by Cdc28 that associates to the ER in a phosphorylation-dependent manner. Our results demonstrate that the Cln3 cyclin and Whi7 act in a positive feedback loop to release the G1 Cdk-cyclin complex and trigger Start once a critical size has been reached, thus uncovering a key nonlinear mechanism at the earliest known events of cell-cycle entry.

Glutamatergic signaling maintains the epithelial phenotype of proximal tubular cells

Epithelial-mesenchymal transition (EMT) contributes to the progression of renal tubulointerstitial fibrosis. The N-methyl-d-aspartate receptor (NMDAR), which is present in proximal tubular epithelium, is a glutamate receptor that acts as a calcium channel. Activation of NMDAR induces actin rearrangement in cells of the central nervous system, but whether it helps maintain the epithelial phenotype of the proximal tubule is unknown. Here, knockdown of NMDAR1 in a proximal tubule cell line (HK-2) induced changes in cell morphology, reduced E-cadherin expression, and increased α-SMA expression. Induction of EMT with TGF-β1 led to downregulation of both E-cadherin and membrane-associated β-catenin, reorganization of F-actin, expression of mesenchymal markers de novo, upregulation of Snail1, and increased cell migration; co-treatment with NMDA attenuated all of these changes. Furthermore, NMDA reduced TGF-β1-induced phosphorylation of Erk1/2 and Akt and the activation of Ras, suggesting that NMDA antagonizes TGF-β1-induced EMT by inhibiting the Ras-MEK pathway. In the unilateral ureteral obstruction model, treatment with NMDA blunted obstruction-induced upregulation of α-SMA, FSP1, and collagen I and downregulation of E-cadherin. Taken together, these results suggest that NMDAR plays a critical role in preserving the normal epithelial phenotype and modulating tubular EMT.

Sustained activation of renal N-methyl-D-aspartate receptors decreases vitamin D synthesis: a possible role for glutamate on the onset of secondary HPT

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are tetrameric amino acid receptors that act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney, bone, and parathyroid gland), pointing to a possible role in mineral metabolism. The aim of this study was to test the effect of NMDAR activation in the kidney and on 1,25(OH)₂D₃ synthesis. We determined the presence of NMDAR subunits in HK-2 (human kidney cells) cells and proved its functionality. NMDA treatment for 4 days induced a decrease in 1α-hydroxylase levels and 1,25(OH)₂D₃ synthesis through the activation of the MAPK/ERK pathway in HK-2 cells. In vivo administration of NMDA for 4 days also caused a decrease in blood 1,25(OH)₂D₃ levels in healthy animals and an increase in blood PTH levels. This increase in PTH induced a decrease in the urinary excretion of calcium and an increase in urinary excretion of phosphorous and sodium as well as in diuresis. Bone turnover markers also increased. Animals with 5/6 nephrectomy showed low levels of renal 1α-hydroxylase as well as high levels of renal glutamate compared with healthy animals. In conclusion, NMDAR activation in the kidney causes a decrease in 1,25(OH)₂D₃ synthesis, which induces an increase on PTH synthesis and release. In animals with chronic kidney disease, high renal levels of glutamate could be involved in the downregulation of 1α-hydroxylase expression.

Degranulation Patterns of Eosinophils in Advanced Gastric Carcinoma: An Electron Microscopic Study

Recruitment and activation of eosinophils have been studied intensely in asthma and other allergic diseases. Less is known about the infiltration and degranulation patterns of eosinophils in the tumor stroma. Seven cases of advanced gastric carcinomas were found to be massively infiltrated by eosinophils and studied by light and electron microscopy. Gastric carcinomas, despite having similar numbers of tissue eosinophils, exhibited markedly different degranulation patterns. In 2 cases, resting nondegranulating eosinophils were found. Piecemeal degranulation was the predominant mode of secretion from eosinophils localized within the tumor stroma in 4 cases. Eosinophil exocytosis and cytolysis were rarely observed. In 1 case, crystals morphologically similar to Charcot-Leyden crystals were observed at the extracellular level as well as in phagosomes of tissue macrophages, confirming active sequestrations of eosinophil Charcot-Leyden protein by macrophages in vivo. In the same case, eosinophils showed characteristic features of early and late apoptotic changes, such as condensed chromatin, focal dilatation of nuclear envelope, and preserved plasma membrane. Morphological association between apoptotic eosinophils and deposition of granules in the tumor stroma was found. Extracellular deposition of intact granules from apoptotic eosinophils was distinct from eosinophilic (necrotic) cytolysis, and has reported previously in experimental studies in vitro. To the knowledge of the authors, this case represents the first report of late apoptotic eosinophils that release their granules within the tumor stroma in a human gastric carcinoma.

N-methyl-D-aspartate receptors are expressed in rat parathyroid gland and regulate PTH secretion

N-methyl-d-aspartate receptors (NMDAR) are tetrameric amino acid receptors which act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney and bone), pointing to a possible role in mineral metabolism. In the present work, the presence of the receptor was determined in normal parathyroid glands (PTG) by real-time PCR, immunoprecipitation, and immunohistrochemistry. Healthy animals showed a decrease in blood parathyroid hormone (PTH) levels 15 min after the treatment with NMDA. This effect was also observed in animals with high levels of PTH-induced EDTA injection, but not in uremic animals with secondary hyperparathyroidism (2HPT). Normal rat PTG incubated in media with low calcium concentration (0.8 mM CaCl2) showed a decrease in PTH release when NMDA was added to the media. This effect of NMDA was abolished when glands were coincubated with MK801 (a pharmacological blocker of the NMDA channel) or PD98059 (an inhibitor of the ERK-MAPK pathway). Glands obtained from animals with 2HPT showed no effect of NMDA in the in vitro release of PTH, together with a decrease in the expression of NMDAR1. In conclusion, NMDA receptor is present in PTG and is involved in the regulation of the PTH release. The mechanism by which NMDAR exerts its function is through the activation of the MAPK cascade. In uremic 2HPT animals the receptor expression is downregulated and the treatment with NMDA does not affect PTH secretion.

RANKL increases vascular smooth muscle cell calcification through a RANK-BMP4-dependent pathway

Vascular calcification commonly associated with several pathologies and it has been suggested to be similar to bone mineralization. The axis RANKL-OPG (receptor activator of nuclear factor kappaB ligand-osteoprotegerin) finely controls bone turnover. RANKL has been suggested to increase vascular calcification, but direct evidence is missing. Thus, in the present work, we assess the effect of RANKL in vascular smooth muscle cell (VSMC) calcification. VSMCs incubated with RANKL showed a dose-dependent increase in calcification, which was abolished by coincubation with OPG. To test whether the effect was mediated by signaling to its receptor, knockdown of RANK was accomplished by short hairpin (sh)RNA. Indeed, cells lacking RANK showed no increases in vascular calcification when incubated with RANKL. To further elucidate the mechanism by which RANK activation increases calcification, we blocked both nuclear factor (NF)-kappaB activation pathways. Only IKKalpha inactivation inhibited calcification, pointing to an involvement of the alternative NF-kappaB activation pathway. Furthermore, RANKL addition increased bone morphogenetic protein (BMP)4 expression in VSMCs, and that increase disappeared in cells lacking RANK or IKKalpha. The increase in calcification was also blunted by Noggin, pointing to a mediation of BMP4 in the calcification induced by RANKL. Furthermore, in an in vivo model, the increase in vascular calcium content was parallel to an increase in RANKL and BMP4 expression, which was localized in calcified areas. However, blood levels of the ratio RANKL/OPG did not change. We conclude that RANKL increases vascular smooth muscle cell calcification by binding to RANK and increasing BMP4 production through activation of the alternative NF-kappaB pathway.

The arginine metabolite agmatine protects mitochondrial function and confers resistance to cellular apoptosis

Agmatine, an endogenous metabolite of arginine, selectively suppresses growth in cells with high proliferative kinetics, such as transformed cells, through depletion of intracellular polyamine levels. In the present study, we depleted intracellular polyamine content with agmatine to determine if attrition by cell death contributes to the growth-suppressive effects. We did not observe an increase in necrosis, DNA fragmentation, or chromatin condensation in Ha-Ras-transformed NIH-3T3 cells administered agmatine. In response to Ca(2+)-induced oxidative stress in kidney mitochondrial preparations, agmatine demonstrated attributes of a free radical scavenger by protecting against the oxidation of sulfhydryl groups and decreasing hydrogen peroxide content. The functional outcome was a protective effect against Ca(2+)-induced mitochondrial swelling and mitochondrial membrane potential collapse. We also observed decreased expression of proapoptotic Bcl-2 family members and of execution caspase-3, implying antiapoptotic potential. Indeed, we found that apoptosis induced by camptothecin or 5-fluorourocil was attenuated in cells administered agmatine. Agmatine may offer an alternative to the ornithine decarboxylase inhibitor difluoromethyl ornithine for depletion of intracellular polyamine content while avoiding the complications of increasing polyamine import and reducing the intracellular free radical scavenger capacity of polyamines. Depletion of intracellular polyamine content with agmatine suppressed cell growth, yet its antioxidant capacity afforded protection from mitochondrial insult and resistance to cellular apoptosis. These results could explain the beneficial outcomes observed with agmatine in models of injury and disease.

Vitamin D receptor levels in colorectal cancer. Possible role of BsmI polymorphism

A high expression of vitamin D receptor (VDR) in colorectal cancer (CRC) tumoral tissue has been related to a good prognosis and it has been proposed that it could be a good biological marker of CRC progression. Nevertheless, there are no previous studies that compare the VDR expression in tumoral towards normal tissue of the same CRC patient in relation to VDR BsmI genotype. We collected normal and tumoral tissue samples, as well as blood samples, from CRC patients (n=170) and controls (n=122). VDR genotyping was performed and BsmI homozygous patients were selected (CRC=50, Cont=32). VDR mRNA and protein levels were analyzed. We also measured 25-Hydroxyvitamin D serum levels. We found no differences in the polymorphism distribution in tumoral versus normal tissue (control: BB=15.7%, bb=41.3%, Bb=43%; CRC: BB=14.2%, bb=41.9%, Bb=43.9%). Furthermore, VDR levels decreased in colonic cancer tissue (mean: 3.03) versus normal mucosa (11.62) from the same patient (p<0.001), but this decrease was similar in both genotypes. There were differences in 25-Hydroxyvitamin D(3) levels between the CRC and the control group (CRC=8.65 ng/ml, Cont=18.15 ng/ml). In conclusion, we found a decrease in VDR levels in tumoral compared with normal mucosa from the same patient. This difference is independent of the BsmI polymorphism.

Differential effects of vitamin D analogs on vascular calcification

We tested the effects of calcitriol and its analog paricalcitol on VSMC calcification in vitro and in vivo. For that reason, cells and animals with five-sixths nephrectomy were treated with both compounds. Calcitriol, but not paricalcitol, increased VSMC calcification in vitro and in vivo independently of calcium and phosphate levels. This increase in calcification was parallel to an increase in the RANKL/OPG ratio.

INTRODUCTION

Vascular calcification is a common finding in patients with endstage renal disease. Furthermore, those patients often present secondary hyperparathyroidism, partly because of a decrease of calcitriol synthesis on the kidney. Thus, one of the main therapeutic options is to treat those patients with calcitriol or analogs. However, this treatment presents unwanted side effects, such as increases in vascular calcification.

MATERIALS AND METHODS

We tested the effect on vascular smooth muscle cell (VSMC) calcification of calcitriol and one of its analogs, paricalcitol, in vitro and in vivo in animals with endstage renal disease.

RESULTS

Calcitriol increased calcification of VSMCs cultured in calcification media. This effect was not present when cells were incubated with paricalcitol. Furthermore, only cells incubated with calcitriol showed an increased RANKL/osteoprotegerin (OPG) expression. Animals with renal failure treated with hypercalcemic doses of calcitriol and paricalcitol showed an increase in systolic blood pressure. However, diastolic blood pressure only raised significantly in those animals treated with paricalcitol. This effect led to a significant increase in pulse pressure in animals treated with calcitriol. The increase in pulse pressure was likely caused by the extensive calcification observed in arteries of animals treated with calcitriol. This increase in calcification was not seen in arteries of animals treated with paricalcitol, despite having similar levels of serum calcium and phosphorus as animals treated with calcitriol. Furthermore, the decreases in serum PTH levels were similar in both treatments.

CONCLUSIONS

We conclude that paricalcitol has a different effect than calcitriol in VSMC calcification and that this could explain part of the differences observed in the clinical settings.

The antiproliferative effects of agmatine correlate with the rate of cellular proliferation

Polyamines are small cationic molecules required for cellular proliferation. Agmatine is a biogenic amine unique in its capacity to arrest proliferation in cell lines by depleting intracellular polyamine levels. We previously demonstrated that agmatine enters mammalian cells via the polyamine transport system. As polyamine transport is positively correlated with the rate of cellular proliferation, the current study examines the antiproliferative effects of agmatine on cells with varying proliferative kinetics. Herein, we evaluate agmatine transport, intracellular accumulation, and its effects on antizyme expression and cellular proliferation in nontransformed cell lines and their transformed variants. H-ras- and Src-transformed murine NIH/3T3 cells (Ras/3T3 and Src/3T3, respectively) that were exposed to exogenous agmatine exhibit increased uptake and intracellular accumulation relative to the parental NIH/3T3 cell line. Similar increases were obtained for human primary foreskin fibroblasts relative to a human fibrosarcoma cell line, HT1080. Agmatine increases expression of antizyme, a protein that inhibits polyamine biosynthesis and transport. Ras/3T3 and Src/3T3 cells demonstrated augmented increases in antizyme protein expression relative to NIH/3T3 in response to agmatine. All transformed cell lines were significantly more sensitive to the antiproliferative effects of agmatine than nontransformed lines. These effects were attenuated in the presence of exogenous polyamines or inhibitors of polyamine transport. In conclusion, the antiproliferative effects of agmatine preferentially target transformed cell lines due to the increased agmatine uptake exhibited by cells with short cycling times.

1,25-Dihydroxyvitamin D3 stimulates vascular smooth muscle cell proliferation through a VEGF-mediated pathway

Atherosclerosis is a complex process characterized by an increase in the wall thickness owing to the accumulation of cells and extracellular matrix between the endothelium and the smooth muscle cell wall. This process is associated with different pathologies and it is accelerated in patients with chronic renal failure. In these patients, decreased synthesis of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) leads to secondary complications, like hyperparathyroidism, and treatment with 1,25(OH)(2)D(3) is a common practice. The effect of 1,25(OH)(2)D(3) on vascular smooth muscle cells (VSMCs) calcification has been widely studied, but the role of 1,25(OH)(2)D(3) on VSMC proliferation remains obscure. We have analyzed the effects of 1,25(OH)(2)D(3) in the proliferation of VSMC. We found that 1,25(OH)(2)D(3) (5-100 nM) induces a dose-dependent increase in VSMC proliferation in quiescent cells and in cells stimulated to grow. This increase in proliferation is achieved by shortening the G1 phase. The effect of 1,25(OH)(2)D(3) on VSMC proliferation is mediated by an increase of the expression of vascular endothelial growth factor A (VEGF), as the inhibition of VEGF activity totally blunted the 1,25(OH)(2) D(3)-induced VSMC proliferation. We found this increase in proliferation in vitro, ex vivo in aortic rings incubated with 1,25(OH)(2)D(3), and in vivo in animals with a model of chronic renal failure (5/6 nephrectomy) treated with 1,25(OH)(2)D(3) (1 mug/kg three times a week for 8 weeks). Thus, we conclude that 1,25(OH)(2)D(3) induces increases in VSMC proliferation through an increase on VEGF expression.

Recurrent intraoral pyogenic granuloma with satellitosis treated with corticosteroids

The development of recurrent pyogenic granulomas as multiple satellite lesions has not been reported in the oral cavity. This report describes an unusual case of intraoral pyogenic granuloma recurring multiple times after surgical excisions with the formation of satellite lesions. Due to failure of surgical management, an alternative approach was taken. We illustrate how the lesions were successfully treated with a series of intralesional corticosteroid injections.

Influence of vitamin D receptor gene polymorphisms and 25-hydroxyvitamin D on blood pressure in apparently healthy subjects

BACKGROUND

There are no studies that relate BsmI polymorphism of the vitamin D receptor (VDR) gene and with vitamin D to blood pressure (BP).

OBJECTIVE

To analyze if this polymorphism and 25-hydroxyvitamin D levels (25OHD3) influence BP in a population of healthy subjects.

DESIGN

Transversal study on healthy population. Stepwise multiple regression analysis was performed to assess the association of BP with several clinical and biochemical data.

SETTING

Industrial employees, blood donors, and army cadets from Lleida, Spain were recruited in October 2001.

INDIVIDUALS

A total of 590 apparently healthy subjects (260 males and 330 females).

MEASUREMENTS

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were determined as the mean of three measurements. We also included age, gender, body mass index (BMI), serum levels of creatinine, calcium, phosphorus, intact parathyroid hormone (by two-site chemiluminometric assay), 25-hydroxyvitamin D (by radioimmunoassay) and BsmI genotype.

RESULTS

Since gender was strongly associated with both SBP and DBP, a separate analysis was performed for men and women. In males, SBP was associated with BMI, 25OHD3 (beta: 0.37, P < 0.000) and genotype (beta: -4.1, P < 0.001); and DBP with 25OHD3 (beta: 0.19, P < 0.008) and age. SBP was higher in men with bb genotype than in the other genotypes (P < 0.006). Moreover, there was a statistically significant positive correlation between 25OHD3 and both SBP (r: 0.53, P < 0.002) and DBP (r: 0.48, P < 0.005) in men with genotype BB. In women, neither 25OHD3 nor genotype were associated with BP levels.

CONCLUSIONS

BsmI polymorphism of the VDR gene influences BP in healthy men. A positive relationship between serum 25-hydroxyvitamin D levels and BP is present only in men with the BB genotype.

[Differential effect of vitamin D analogues on the proliferation of vascular smooth muscle cells]

Atherosclerosis is the principal cause of myocardial infarction, stroke, and peripheral vascular disease, accounting for nearly half of all mortality in developed countries. The excessive growth of vascular smooth muscle cells is an important component in the development of atherosclerotic lesion. The direct effect of calcitriol and vitamin D analogs on the VSMCs proliferation is not clear. In this study we have analysed if calcitriol, Paricalcitol (19-nor-1,25-dihydroxy-vitamin D2) and EB1089 (experimental analog used as anticancerous) modify proliferation and the expression of vitamin D receptor (VDR) gene that is regulated at the transcriptional level by itself in the VSMCs. VSMCs proliferation was analysed by BrdU incorporation and VDR gene expression using RT-PCR. VSMCs proliferation was stimulated when calcitriol was added to the culture. VSMCs proliferation was significantly lower with analogs at the same dose. With regard to the functional study, the expression of VDR gene was upregulated by calcitriol at a concentration of 100 nM. There were no changes in this expression with the analogs. In conclusion, calcitriol, do not modify VSMCs proliferation. Therefore, Paricalcitol could have a minor proliferating effect on the wall of vessels that vitamin D.

[Influence of the vitamin D receptor gene polymorphism and 25-hydroxyvitamin D on arterial pressure in health individuals]

The role of vitamin D in the regulation of blood pressure is unclear. There are no studies that relate Bsm I polymorphism with blood pressure.

OBJECTIVE

To analyze if Bsm I polymorphism and 25-hydroxyvitamin D (25OHD3) influence blood pressure in healthy individuals with normal blood pressure.

METHODS

Systolic (SBP) and diastolic (DBP) blood pressure, Body Mass Index (BMI), plasma creatinine, serum calcium, serum phosphorus, serum iPTH, serum 25OHD3 and Bsm I genotype were determined in 590 healthy individuals (260 men and 330 women). Data were analysed using a multiple linear regression model. SBP and DBP were defined as dependent variables and the rest of variables as independent.

RESULTS

Gender was strongly associated with both SBP (beta: -12.01, p: 0.000) and DBP (beta: -4.78, p: 0.000). Therefore, a separate analysis was performed according to gender. In males, SBP was associated with BMI (beta: 0.83, p: 0.001), 25OHD3, (beta: 0.36, p: 0.000) and genotype (beta: -3.90, p: 0.002); and DBP with 25OHD 3 (beta: 0.16, p: 0.018) and age (beta: 0.28, p: 0.000). Differences of blood pressure among the three genotypes were explored by analysis of variance. SBP was higher in men with bb genotype than in the other genotypes (p: 0.007). In females, 25OHD3 and genotype were not associated with blood pressure.

CONCLUSIONS

Healthy men with higher levels of vitamin D have higher levels of SBP and DBP. Moreover, men with bb genotype have the highest levels of SBP. Blood pressure levels in women are not influenced by vitamin D nor by Bsml genotype. Our data suggest a possible pathophysiological interaction between vitamin D and sex hormones in blood pressure control.

Identification of cadmium-sensitive genes in the Antarctic fish Chionodraco hamatus by messenger RNA differential display

To investigate the ability of cadmium to affect gene transcription in fish, the messenger RNA (mRNA) differential display technique was used to analyze gene expression in the Antarctic icefish Chionodraco hamatus exposed to sublethal doses of cadmium salt. Seven DNA complementary to RNA (cDNA) bands whose steady-state levels of expression significantly changed in response to cadmium exposure were identified. The results obtained show that two groups of genes are affected by cadmium in icefish liver. The first group comprises genes that are up-regulated by the metal: in particular, a gene encoding the heat-shock protein HSP70 and another encoding a protein homologous to GP49 of Sparus aurata egg envelope. The other group comprises genes down-regulated by cadmium. These are the transferrin gene and a gene encoding a protein presenting homology to mouse T2K, a kinase having a role in the prevention of apoptosis. Three cDNAs had no homology to known gene sequences, thus suggesting that may either encode not yet identified proteins, or correspond to untranslated regions of mRNA molecules.

Molecular cloning, sequence and expression of follicle-stimulating hormone receptor in the lizard Podarcis sicula

The present paper reports the full nucleotide sequence of a cloned cDNA prepared from RNA of lizard ovaries. The open reading frame consists of 2019 nucleotides, which encodes a protein of 673 amino acids belonging to the G protein-coupled receptor superfamily with a large extracellular N-terminal domain involved in hormone recognition. The transmembrane domain ends with a short intracytoplasmic COOH-terminal domain involved in effector activation. Phylogenetic analysis showed that the lizard receptor belongs to the family of follicle-stimulating hormone (FSH) receptors. The hydrophobicity profile is similar to that observed for mammalian and avian FSH receptors. Northern blot analysis of total RNA revealed that the FSH receptor is expressed at high levels in the ovary. In situ hybridization experiments demonstrate that FSH receptor mRNA is specifically localized within the small cells of the follicular epithelium surrounding the oocyte.