Genomic Landscape of Normal and Breast Cancer Tissues in a Hungarian Pilot Cohort

A limited number of studies have focused on the mutational landscape of breast cancer in different ethnic populations within Europe and compared the data with other ethnic groups and databases. We performed whole-genome sequencing of 63 samples from 29 Hungarian breast cancer patients. We validated a subset of the identified variants at the DNA level using the Illumina TruSight Oncology (TSO) 500 assay. Canonical breast-cancer-associated genes with pathogenic germline mutations were CHEK2 and ATM. Nearly all the observed germline mutations were as frequent in the Hungarian breast cancer cohort as in independent European populations. The majority of the detected somatic short variants were single-nucleotide polymorphisms (SNPs), and only 8% and 6% of them were deletions or insertions, respectively. The genes most frequently affected by somatic mutations were KMT2C (31%), MUC4 (34%), PIK3CA (18%), and TP53 (34%). Copy number alterations were most common in the NBN, RAD51C, BRIP1, and CDH1 genes. For many samples, the somatic mutational landscape was dominated by mutational processes associated with homologous recombination deficiency (HRD). Our study, as the first breast tumor/normal sequencing study in Hungary, revealed several aspects of the significantly mutated genes and mutational signatures, and some of the copy number variations and somatic fusion events. Multiple signs of HRD were detected, highlighting the value of the comprehensive genomic characterization of breast cancer patient populations.

Proteomic analysis of brain metastatic lung adenocarcinoma reveals intertumoral heterogeneity and specific alterations associated with the timing of brain metastases

BACKGROUND

Brain metastases are associated with considerable negative effects on patients' outcome in lung adenocarcinoma (LADC). Here, we investigated the proteomic landscape of primary LADCs and their corresponding brain metastases.

MATERIALS AND METHODS

Proteomic profiling was conducted on 20 surgically resected primary and brain metastatic LADC samples via label-free shotgun proteomics. After sample processing, peptides were analyzed using an Ultimate 3000 pump coupled to a QExactive HF-X mass spectrometer. Raw data were searched using PD 2.4. Further data analyses were carried out using Perseus, RStudio and GraphPad Prism. Proteomic data were correlated with clinical and histopathological parameters and the timing of brain metastases. Mass spectrometry-based proteomic data are available via ProteomeXchange with identifier PXD027259.

RESULTS

Out of the 6821 proteins identified and quantified, 1496 proteins were differentially expressed between primary LADCs and corresponding brain metastases. Pathways associated with the immune system, cell-cell/matrix interactions and migration were predominantly activated in the primary tumors, whereas pathways related to metabolism, translation or vesicle formation were overrepresented in the metastatic tumors. When comparing fast- versus slow-progressing patients, we found 454 and 298 differentially expressed proteins in the primary tumors and brain metastases, respectively. Metabolic reprogramming and ribosomal activity were prominently up-regulated in the fast-progressing patients (versus slow-progressing individuals), whereas expression of cell-cell interaction- and immune system-related pathways was reduced in these patients and in those with multiple brain metastases.

CONCLUSIONS

This is the first comprehensive proteomic analysis of paired primary tumors and brain metastases of LADC patients. Our data suggest a malfunction of cellular attachment and an increase in ribosomal activity in LADC tissue, promoting brain metastasis. The current study provides insights into the biology of LADC brain metastases and, moreover, might contribute to the development of personalized follow-up strategies in LADC.

Qualitative Analysis of Tumor-Infiltrating Lymphocytes across Human Tumor Types Reveals a Higher Proportion of Bystander CD8+ T Cells in Non-Melanoma Cancers Compared to Melanoma

Background: Human intratumoral T cell infiltrates can be defined by quantitative or qualitative features, such as their ability to recognize autologous tumor antigens. In this study, we reproduced the tumor-T cell interactions of individual patients to determine and compared the qualitative characteristics of intratumoral T cell infiltrates across multiple tumor types. Methods: We employed 187 pairs of unselected tumor-infiltrating lymphocytes (TILs) and autologous tumor cells from patients with melanoma, renal-, ovarian-cancer or sarcoma, and single-cell RNA sequencing data from a pooled cohort of 93 patients with melanoma or epithelial cancers. Measures of TIL quality including the proportion of tumor-reactive CD8+ and CD4+ TILs, and TIL response polyfunctionality were determined. Results: Tumor-specific CD8+ and CD4+ TIL responses were detected in over half of the patients in vitro, and greater CD8+ TIL responses were observed in melanoma, regardless of previous anti-PD-1 treatment, compared to renal cancer, ovarian cancer and sarcoma. The proportion of tumor-reactive CD4+ TILs was on average lower and the differences less pronounced across tumor types. Overall, the proportion of tumor-reactive TILs in vitro was remarkably low, implying a high fraction of TILs to be bystanders, and highly variable within the same tumor type. In situ analyses, based on eight single-cell RNA-sequencing datasets encompassing melanoma and five epithelial cancers types, corroborated the results obtained in vitro. Strikingly, no strong correlation between the proportion of CD8+ and CD4+ tumor-reactive TILs was detected, suggesting the accumulation of these responses in the tumor microenvironment to follow non-overlapping biological pathways. Additionally, no strong correlation between TIL responses and tumor mutational burden (TMB) in melanoma was observed, indicating that TMB was not a major driving force of response. No substantial differences in polyfunctionality across tumor types were observed. Conclusions: These analyses shed light on the functional features defining the quality of TIL infiltrates in cancer. A significant proportion of TILs across tumor types, especially non-melanoma, are bystander T cells. These results highlight the need to develop strategies focused on the tumor-reactive TIL subpopulation.

Extracellular Vesicle-Based Communication May Contribute to the Co-Evolution of Cancer Stem Cells and Cancer-Associated Fibroblasts in Anti-Cancer Therapy

Analogously to the natural selective forces in ecosystems, therapies impose selective pressure on cancer cells within tumors. Some tumor cells can adapt to this stress and are able to form resistant subpopulations, parallel with enrichment of cancer stem cell properties in the residual tumor masses. However, these therapy-resistant cells are unlikely to be sufficient for the fast tumor repopulation and regrowth by themselves. The dynamic and coordinated plasticity of residual tumor cells is essential both for the conversion of their regulatory network and for the stromal microenvironment to produce cancer supporting signals. In this nursing tissue "niche", cancer-associated fibroblasts are known to play crucial roles in developing therapy resistance and survival of residual stem-like cells. As paracrine messengers, extracellular vesicles carrying a wide range of signaling molecules with oncogenic potential, can support the escape of some tumor cells from their deadly fate. Here, we briefly overview how extracellular vesicle signaling between fibroblasts and cancer cells including cancer progenitor/stem cells may contribute to the progression, therapy resistance and recurrence of malignant tumors.

Origin and Distribution of Connective Tissue and Pericytes Impacting Vascularization in Brain Metastases With Different Growth Patterns

The impact of growth pattern on the distribution of connective tissue and on the vascularization of brain metastases (40 colon, lung and breast carcinoma samples) was analyzed. Most of the cases showed either a "pushing-type" (18/40, mostly colon and lung carcinomas) or a "papillary-type" (19/40, mostly breast carcinomas) growth pattern. There was a striking difference in the growth pattern and vascularization of colon/lung versus breast carcinoma metastases. Pushing-type brain metastases incorporated fewer vessels and accumulated more collagen in the adjacent brain parenchyma, whereas papillary-type brain metastases incorporated more vessels and accumulated collagen in the center of the tumor. We observed duplication of the PDGFRβ-positive pericyte layer accompanied by an increase in the amount of collagen within the vessel walls. The outer layer of pericytes and the collagen was removed from the vessel by invasive activity of the tumors, which occurred either peri- or intratumorally, depending on the growth pattern of the metastasis. Our findings suggest that pericytes are the main source of the connective tissue in brain metastases. Vascularization and connective tissue accumulation of the brain metastases largely depend on the growth pattern of the tumors.

[Possibilities of immune checkpoint inhibitor therapy for patients with metastatic non-small cell lung cancer]

Survival of patients with lung cancer is unfavorable. Distant metastasis is detected in more than half of the patients at diagnosis. In advanced stages, platinum-based chemotherapy has been the main therapeutic approach for a long time, however, in 2004 targeted therapies emerged. Recently, PDL1/ PD-1 inhibitors have been introduced in the treatment of metastatic lung cancers, for which the therapeutic criteria are increasingly outlined. Based on international and Hungarian data, it is likely that determination of PD-L1 expression in the primary tumor samples may be sufficient for the establishment of therapeutic indication, if PD-L1 expression of tumor cells remains the sole criterion. However, if the combined positive score, which takes into account PD-L1 expression of both tumor and immune cells, will be introduced as a therapeutic criterion, testing of all the actual tumor samples may be required to initiate treatment, as conventional oncotherapies may affect the PD-L1 expression of immune cells.

Tumor necrosis correlates with PD-L1 and PD-1 expression in lung adenocarcinoma

Background: Predictive biomarkers for immunotherapy in lung cancer are intensively investigated; however, correlations between PD-L1/PD-1 expressions and clinical features or histopathological tumor characteristics determined on hematoxylin and eosin stained sections have not extensively been studied. Material and methods: We determined PD-L1 expression of tumor cells (TC) and immune cells (IC), and PD-1 expression of IC by immunohistochemistry in 268 lung adenocarcinoma (LADC) patients, and correlated the data with smoking, COPD, tumor grade, necrosis, lepidic growth pattern, vascular invasion, density of stromal IC, and EGFR/KRAS status of the tumors. Results: There was a positive correlation between PD-L1 expression of TC and IC, as well as PD-L1 and PD-1 expression of IC. Tumor necrosis was associated with higher PD-L1 expression of TC and PD-1 expression of IC. A negative correlation was observed between lepidic growth pattern and PD-L1 expression of TC and PD-L1/PD-1 expression of IC. EGFR mutation seemed to negatively correlate with PD-1 expression of IC, but this tendency could not be verified when applying corrections for multiple comparisons. No significant effect of the KRAS mutation on any of the studied variables could be established. Conclusion: Here we first demonstrate that the presence of necrosis correlates with higher PD-L1 expression of TC and PD-1 expression of IC in LADC. Further studies are required to determine the predictive value of this observation in LADC patients receiving immunotherapy.

Discrepancy Between Low Levels of mTOR Activity and High Levels of P-S6 in Primary Central Nervous System Lymphoma May Be Explained by PAS Domain-Containing Serine/Threonine-Protein Kinase-Mediated Phosphorylation

The primary aim of this study was to determine mTOR-pathway activity in primary central nervous system lymphoma (PCNSL), which could be a potential target for therapy. After demonstrating that p-S6 positivity largely exceeded mTOR activity, we aimed to identify other pathways that may lead to S6 phosphorylation. We measured mTOR activity with immunohistochemistry for p-mTOR and its downstream effectors p(T389)-p70S6K1, p-S6, and p-4E-BP1 in 31 cases of PCNSL and 51 cases of systemic diffuse large B-cell lymphoma (DLBCL) and evaluated alternative S6 phosphorylation pathways with p-RSK, p(T229)-p70S6K1, and PASK antibodies. Finally, we examined the impact of PASK inhibition on S6 phosphorylation on BHD1 cell line. mTOR-pathway activity was significantly less frequent in PCNSL compared with DLBCL. p-S6 positivity was related to mTOR-pathway in DLBCL, but not in PCNSL. Among the other kinases potentially responsible for S6 phosphorylation, PASK proved to be positive in all cases of PCNSL and DLBCL. Inhibition of PASK resulted in reduced expression of p-S6 in BHD1-cells. This is the first study demonstrating an mTOR independent p-S6 activity in PCNSL and that PASK may contribute to the phosphorylation of S6. Our findings also suggest a potential role of PASK in the pathomechanism of PCNSL and in DLBCL.

En bloc release of MVB-like small extracellular vesicle clusters by colorectal carcinoma cells

Small extracellular vesicles (EVs) are membrane enclosed structures that are usually released from cells upon exocytosis of multivesicular bodies (MVBs) as a collection of separate, free EVs. In this study, we analysed paraffin embedded sections of archived human colorectal cancer samples. We studied 3D reconstructions of confocal microscopic images complemented by HyVolution and STED imaging. Unexpectedly, we found evidence that large, MVB-like aggregates of ALIX/CD63 positive EV clusters were released en bloc by migrating tumour cells. These structures were often captured with partial or complete extra-cytoplasmic localization at the interface of the plasma membrane of the tumour cell and the stroma. Their diameter ranged between 0.62 and 1.94 μm (mean±S.D.: 1.17 ± 0.34 μm). High-resolution 3D reconstruction showed that these extracellular MVB-like EV clusters were composed of distinguishable internal particles of small EV size (mean±S.D.: 128.96 ± 16.73 nm). In vitro, HT29 colorectal cancer cells also showed the release of similar structures as confirmed by immunohistochemistry and immune electron microscopy. Our results provide evidence for an en bloc transmission of MVB-like EV clusters through the plasma membrane. Immunofluorescent-based detection of the MVB like small EV clusters in archived pathological samples may represent a novel and unique opportunity which enables analysis of EV release in situ in human tissues.

Perspective: bidirectional exosomal transport between cancer stem cells and their fibroblast-rich microenvironment during metastasis formation

Carcinomas are complex structures composed of hierarchically organized distinct cell populations such as cancer stem cells and non-stem (bulk) cancer cells. Their genetic/epigenetic makeup and the dynamic interplay between the malignant cell populations and their stromal fibroblasts are important determinants of metastatic tumor invasion. Important mediators of these interactions are the small, membrane-enclosed extracellular vesicles, in particular exosomes. Both cancer cell and fibroblast-derived exosomes carry a set of regulatory molecules, including proteins and different species of RNA, which cooperatively support metastatic tumor spread. Here, we briefly overview potential links between cancer stem cells and the exosome-mediated fibroblast-enriched metastatic niche formation to discuss their role in the promotion of tumor growth and metastatic expansion in breast carcinoma models.

A Somatically Acquired Enhancer of the Androgen Receptor Is a Noncoding Driver in Advanced Prostate Cancer

Increased androgen receptor (AR) activity drives therapeutic resistance in advanced prostate cancer. The most common resistance mechanism is amplification of this locus presumably targeting the AR gene. Here, we identify and characterize a somatically acquired AR enhancer located 650 kb centromeric to the AR. Systematic perturbation of this enhancer using genome editing decreased proliferation by suppressing AR levels. Insertion of an additional copy of this region sufficed to increase proliferation under low androgen conditions and to decrease sensitivity to enzalutamide. Epigenetic data generated in localized prostate tumors and benign specimens support the notion that this region is a developmental enhancer. Collectively, these observations underscore the importance of epigenomic profiling in primary specimens and the value of deploying genome editing to functionally characterize noncoding elements. More broadly, this work identifies a therapeutic vulnerability for targeting the AR and emphasizes the importance of regulatory elements as highly recurrent oncogenic drivers.

LAPTM4B gene copy number gain is associated with inferior response to anthracycline-based chemotherapy in hormone receptor negative breast carcinomas

PURPOSE

To determine the associations between lysosomal-associated transmembrane protein 4b (LAPTM4B) gene copy number and response to different chemotherapy regimens in hormone receptor negative (HR-) primary breast carcinomas.

PATIENTS AND METHODS

Two cohorts were analyzed: (1) 69 core biopsies from HR-breast carcinomas treated with neoadjuvant chemotherapy (anthracycline based in 72.5% of patients and non-anthracycline based in 27.5% of patients). (2) Tissue microarray (TMA) of 74 HR-breast carcinomas treated with adjuvant therapy (77.0% of the patients received anthracycline, 17.6% of the patients non-anthracycline-based therapy, and in 5.4% of the cases, no treatment data are available). Interphase FISH technique was applied on pretreatment core biopsies (cohort I) and on TMAs (cohort II) using custom-made dual-labelled FISH probes (LAPTM4B/CEN8q FISH probe Abnova Corp.).

RESULTS

In the neoadjuvant cohort in the anthracycline-treated group, we observed a significant difference (p = 0.029) of average LAPTM4B copy number between the non-responder and pathological complete responder groups (4.1 ± 1.1 vs. 2.6 ± 0.1). In the adjuvant setting, the anthracycline-treated group of metastatic breast carcinomas was characterized by higher LAPTM4B copy number comparing to the non-metastatic ones (p = 0.046). In contrast, in the non-anthracycline-treated group of patients, we did not find any LAPTM4B gene copy number differences between responder vs. non-responder groups or between metastatic vs. non-metastatic groups.

CONCLUSION

Our results confirm the possible role of the LAPTM4B gene in anthracycline resistance in HR- breast cancer. Analyzing LAPTM4B copy number pattern may support future treatment decision.

Chemotherapy treatment is associated with altered PD-L1 expression in lung cancer patients

OBJECTIVES

While the predictive value of programmed cell death ligand-1 (PD-L1) protein expression for immune checkpoint inhibitor therapy of lung cancer has been extensively studied, the impact of standard platinum-based chemotherapy on PD-L1 or programmed cell death-1 (PD-1) expression is unknown. The aim of this study was to determine the changes in PD-L1 expression of tumor cells (TC) and immune cells (IC), in PD-1 expression of IC, and in the amount of stromal mononuclear cell infiltration after platinum-based chemotherapy in patients with lung cancer.

MATERIALS AND METHODS

We determined the amount of stromal mononuclear cells and PD-L1/PD-1 expressions by immunohistochemistry in bronchoscopic biopsy samples including 20 adenocarcinomas (ADC), 15 squamous cell carcinomas (SCC), 2 other types of non-small cell lung cancer, and 4 small cell lung cancers together with their corresponding surgical resection tissues after platinum-based chemotherapy.

RESULTS

PD-L1 expression of TC decreased in ten patients (24.4%) and increased in three patients (7.32%) after neoadjuvant chemotherapy (p = 0.051). The decrease in PD-L1 expression, however, was significant only in patients who received cisplatin-gemcitabine combination (p = 0.020), while in the carboplatin-paclitaxel group, no similar tendency could be observed (p = 0.432). There was no difference between ADC and SCC groups. Neither PD-1 expression nor the amount of stromal IC infiltration showed significant changes after chemotherapy.

CONCLUSIONS

This is the first study, in which both PD-L1 and PD-1 expression were analyzed together with the amount of stromal IC infiltration in different histological subtypes of lung cancer before and after platinum-based chemotherapy. Our results confirm that chemotherapy decreases PD-L1 expression of TC in a subset of patients, therefore, rebiopsy and re-evaluation of PD-L1 expression may be necessary for the indication of immune checkpoint inhibitor therapy.

Universal scaling laws in metro area election results

We explain the anomaly of election results between large cities and rural areas in terms of urban scaling in the 1948–2016 US elections and in the 2016 EU referendum of the UK. The scaling curves are all universal and depend on a single parameter only, and one of the parties always shows superlinear scaling and drives the process, while the sublinear exponent of the other party is merely the consequence of probability conservation. Based on the recently developed model of urban scaling, we give a microscopic model of voter behavior in which we replace diversity characterizing humans in creative aspects with social diversity and tolerance. The model can also predict new political developments such as the fragmentation of the left and the immigration paradox.

Opposite prognostic roles of HIF1α and HIF2α expressions in bone metastatic clear cell renal cell cancer

BACKGROUND

Prognostic markers of bone metastatic clear cell renal cell cancer (ccRCC) are poorly established. We tested prognostic value of HIF1α/HIF2α and their selected target genes in primary tumors and corresponding bone metastases.

RESULTS

Expression of HIF2α was lower in mRCC both at mRNA and protein levels (p/mRNA/=0.011, p/protein/=0.001) while HIF1α was similar to nmRCC. At the protein level, CAIX, GAPDH and GLUT1 were increased in mRCC. In all primary RCCs, low HIF2α and high HIF1α as well as CAIX, GAPDH and GLUT1 expressions correlated with adverse prognosis, while VEGFR2 and EPOR gene expressions were associated with favorable prognosis. Multivariate analysis confirmed high HIF2α protein expression as an independent risk factor. Prognostic validation of HIFs, LDH, EPOR and VEGFR2 in RNA-Seq data confirmed higher HIF1α gene expression in primary RCC as an adverse (p=0.07), whereas higher HIF2α and VEGFR2 expressions as favorable prognostic factors. HIF1α/HIF2α-index (HIF-index) proved to be an independent prognostic factor in both the discovery and the TCGA cohort.

PATIENTS AND METHODS

Expressions of HIF1α and HIF2α as well as their 7 target genes were analysed on the mRNA and protein level in 59 non-metastatic ccRCCs (nmRCC), 40 bone metastatic primary ccRCCs (mRCC) and 55 corresponding bone metastases. Results were validated in 399 ccRCCs from the TCGA project.

CONCLUSIONS

We identified HIF2α protein as an independent marker of the metastatic potential of ccRCC, however, unlike HIF1α, increased HIF2α expression is a favorable prognostic factor. The HIF-index incorporated these two markers into a strong prognostic biomarker of ccRCC.

Renal Impairment Hampers Bisphosphonate Treatment in a Quarter of Lung Cancer Patients with Bone Metastasis

Renal function impairment in lung cancer patients with bone metastases was investigated, as this can limit the application of bisphosphonates representing the gold standard in the management of such cases. Clinicopathological data of 570 lung cancer patients were retrospectively analysed for changes in renal function parameters. Co-morbidities included hypertension (50%), COPD (33%) and diabetes mellitus (15%). Statistical analysis was performed with Fisher's exact tests and a Cox proportional hazards model. In patients suffering from hypertension, both median serum creatinine and blood urea nitrogen (BUN) were higher (81.9 versus 75.8 μmol/l, p<0.001 and 6.0 versus 5.7 mmol/l, p=0.005, respectively). Such a difference could not be observed in patients with diabetes. In COPD patients, only serum creatinine was higher (81.1 versus 77.3 μmol/l, p=0.004). In the whole cohort, we found that while at the time of lung cancer diagnosis the ratio of patients in the pathological range (PRR) was 8.67% for serum creatinine (median: 75 μmol/l) and 14.16% for BUN (median: 5.4 mmol/l), at the time of bone metastasis the PRR for serum creatinine increased to 16.11% (median: 77.0 μmol/l) and for BUN to 24.07% (median: 6.0 mmol/l), which is a significant increase for both parameters (p<0.001). For the whole cohort, the last laboratory results showed a 26.37% PRR for serum creatinine and 45.66% PRR for BUN (significant increase for both, p<0.001). Multivariate analysis revealed that patients with hypertension had a higher chance for switching to the pathological range sooner (p=0.033, HR: 1.372, CI: 1.025-1.835). Also, the appearance of the bone metastasis correlated with an acceleration of the onset of such a switch (p<0.001, HR: 2.655, CI: 1.581-4.456). Our results suggest that renal function is impaired in a significant proportion of lung cancer patients and highlight the importance of non-nephrotoxic drug in the management of bone metastases. This article is protected by copyright. All rights reserved.

Evaluating the significance of density, localization, and PD-1/PD-L1 immunopositivity of mononuclear cells in the clinical course of lung adenocarcinoma patients with brain metastasis

BACKGROUND

Management of lung cancer patients who suffer from brain metastases represents a major challenge. Considering the promising results with immune checkpoint inhibitor treatment, evaluating the status of immune cell (IC) infiltrates in the prognosis of brain metastasis may lead to better therapeutic strategies with these agents. The aim of this study was to characterize the distribution of ICs and determine the expression of the checkpoint molecules programmed death protein 1 (PD-1) and its ligand, PD-L1, in brain metastasis of lung adenocarcinoma (LUAD) patients and to analyze their clinicopathological correlations.

METHODS

We determined the presence of peritumoral mononuclear cells (mononuclear ring) and the density of intratumoral stromal mononuclear cells on brain metastasis tissue sections of 208 LUAD patients. PD-L1/PD-1 expressions were analyzed by immunohistochemistry.

RESULTS

Mononuclear rings were significantly associated with better survival after brain metastasis surgery. Cases with massive stromal IC infiltration also showed a tendency for better overall survival. Lower expression of PD-1 and PD-L1 was associated with better survival in patients who underwent surgery for the primary tumor and had multiple brain metastases. Steroid administration and chemotherapy appear not to influence the density of IC in brain metastasis.

CONCLUSION

This is the first study demonstrating the independent prognostic value of mononuclear rings in LUAD cases with brain metastasis. Our results also suggest that the density of tumor-associated ICs in addition to PD-L1 expression of tumor cells and ICs as well as PD-1 expression of ICs may hold relevant information for the appropriate selection of patients who might benefit from anti-PD-L1 or anti-PD-1 therapy.

Renal Impairment Hampers Bisphosphonate Treatment in a Quarter of Lung Cancer Patients with Bone Metastasis

Renal function impairment in lung cancer patients with bone metastases was investigated, as this can limit the application of bisphosphonates representing the gold standard in the management of such cases. Clinicopathological data of 570 lung cancer patients were retrospectively analysed for changes in renal function parameters. Comorbidities included hypertension (50%), COPD (33%) and diabetes mellitus (15%). Statistical analysis was performed with Fisher's exact tests and a Cox proportional hazards model. In patients suffering from hypertension, both median serum creatinine and blood urea nitrogen (BUN) were higher (81.9 versus 75.8 μmol/L, p < 0.001 and 6.0 versus 5.7 mmol/L, p = 0.005, respectively). Such a difference could not be observed in patients with diabetes. In patients with COPD, only serum creatinine was higher (81.1 versus 77.3 μmol/L, p = 0.004). In the whole cohort, we found that while at the time of lung cancer diagnosis the ratio of patients in the pathological range (PRR) was 8.67% for serum creatinine (median: 75 μmol/L) and 14.16% for BUN (median: 5.4 mmol/L), at the time of bone metastasis the PRR for serum creatinine increased to 16.11% (median: 77.0 μmol/L) and for BUN to 24.07% (median: 6.0 mmol/L), which is a significant increase for both parameters (p < 0.001). For the whole cohort, the last laboratory results showed a 26.37% PRR for serum creatinine and 45.66% PRR for BUN (significant increase for both, p < 0.001). Multivariate analysis revealed that patients with hypertension had a higher chance for switching to the pathological range sooner (p = 0.033, HR: 1.372, CI: 1.025-1.835). Also, the appearance of the bone metastasis correlated with an acceleration of the onset of such a switch (p < 0.001, HR: 2.655, CI: 1.581-4.456). Our results suggest that renal function is impaired in a significant proportion of patients with lung cancer and highlight the importance of non-nephrotoxic drug in the management of bone metastases.

Paraneoplastic thrombocytosis in gastrointestinal cancer

It has been demonstrated recently in several solid tumors that thrombocytosis at diagnosis may correlate with tumor invasion, metastatic progression and worse outcome. Several details of the pathomechanism of the relationship of thrombocytosis and cancer have been elucidated; however, the complete process is not clearly understood. Several hypotheses have been proposed. Recently, it was suggested that in ovarian cancer elevated IL-6 production by the tumor may induce increased megakaryopoiesis via hepatic thrombopoietin production leading to thrombocytosis. The importance of the prognostic power of elevated platelet count is still debated in gastrointestinal cancer. The aims of this review were to evaluate the prognostic significance of thrombocytosis in gastrointestinal tumors, to see whether clinical practice confirmed the hypotheses and to reveal the causes of the inconsistent findings.

CAUSEL: an epigenome- and genome-editing pipeline for establishing function of noncoding GWAS variants

The vast majority of disease-associated single nucleotide polymorphisms (SNPs) mapped by genome-wide association studies (GWAS) are located in the non-protein coding genome, but establishing the functional and mechanistic roles of these sequence variants has proven challenging. Here, we describe a general pipeline in which candidate functional SNPs are first evaluated by fine-mapping, epigenomic profiling, and epigenome editing and then interrogated for causal function by using genome editing to create isogenic cell lines. To validate this approach, we analyzed the 6q22.1 prostate cancer risk locus and identified rs339331 as the top scoring SNP. Epigenome editing confirmed that rs339331 possessed regulatory potential. Using transcription activator-like effector nuclease (TALEN)-mediated genome-editing, we created a panel of isogenic 22Rv1 prostate cancer cell lines representing all three genotypes (TT, TC, CC) at rs339331. Introduction of the “T” risk allele increased transcription of the RFX6 gene, increased HOXB13 binding at the rs339331 region, and increased deposition of the enhancer-associated H3K4me2 histone mark at the rs339331 region. The cell lines also differed in cellular morphology and adhesion, and pathway analysis of differentially expressed genes suggested an influence of androgens. In summary, we have developed and validated a widely accessible approach to establish functional causality for non-coding sequence variants identified by GWAS.

Thrombocytosis of Liver Metastasis from Colorectal Cancer as Predictive Factor

There is increasing evidence that thrombocytosis is associated with tumor invasion and metastasis formation. It was shown in several solid tumor types that thrombocytosis prognosticates cancer progression. The aim of this study was to evaluate preoperative thrombocytosis as a potential prognostic biomarker in isolated metastases, in patients with liver metastasis of colorectal cancer (mCRC). Clinicopathological data of 166 patients with mCRC who had surgical resection between 2001 and 2011 were collected retrospectively. All primary tumors have been already resected. The platelet count was evaluated based on the standard preoperative blood profile. The patients were followed-up on average for 28 months. Overall survival (OS) of patients with thrombocytosis was significantly worse both in univariate (HR = 3.00, p = 0.03) and in multivariate analysis (HR = 4.68, p = 0.056) when adjusted for gender, age, tumor size and surgical margin. Thrombocytosis was also a good prognosticator of disease-free survival (DFS) with HR = 2.7, p = 0.018 and nearly significant in multivariate setting (HR = 2.26, p = 0.073). The platelet count is a valuable prognostic marker for the survival in patients with mCRC.

[Evaluation of thrombocytosis as predictive factor in colorectal cancer]

INTRODUCTION/AIM OF THE STUDY: Preoperative thrombocytosis proved to be a negative prognostic factor in several solid tumor. However, there is still debate in the literature regarding colorectal cancer. The aim of our study was to examine whether thrombocytosis is an independent risk factor for metastasis development and predictor of survival in colorectal cancer.

MATERIALS AND METHODS

Clinicopathological data of 336 patients with colorectal cancer (CRC) and 118 patients with liver metastasis of colorectal cancer (mCRC) who had operation between 2001 and 2011 were collected retrospectively. Thrombocytosis was defined as 400 G/L < platelet count. Disease-free survival (DFS) and overall survival (OS) were determined with Kaplan-Meier method supported by log-rank test.

RESULTS

Both in the CRC and the mCRC group OS was significantly shorter in patients who had elevated platelet count (HR = 2.2, p < 0.001 and HR = 2.9, p = 0.018, respectively). Multivariate analysis confirmed that elevated platelet count was an independent prognostic factor of both CRC (HR = 1.7, p = 0.035) and mCRC (HR = 3.1, p = 0.017). DFS was significantly shorter in patients with elevated platelet count in the CRC group (HR = 2.0, p = 0.011).

DISCUSSION

The platelet count is a valuable and cheap prognostic marker for the prediction of survival in patients both with CRC and mCRC.

The comparison of thrombocytosis and platelet-lymphocyte ratio as potential prognostic markers in colorectal cancer

The aim of the present study was to analyse the preoperative platelet count and the platelet-lymphocyte ratio (PLR) in patients with colorectal cancer (CRC) of different stages and with hepatic metastasis of CRC (mCRC) and to compare these factors as potential prognostic markers. Clinicopathological data of 10 years were collected retrospectively from 336 patients with CRC and 118 patients with mCRC. Both in the CRC and the mCRC group overall survival (OS) was significantly worse in patients who had elevated platelet count (hazard ratio [HR] = 2.2, p < 0.001 and HR = 2.9, p = 0.018, respectively). Multivariate analysis indicated that elevated platelet count was an independent prognostic factor of CRC (HR = 1.7, p = 0.035) and mCRC (HR = 3.1, p = 0.017). Disease-free survival (DFS) was significantly worse in patients with elevated platelet count in the CRC group (HR = 2.0, p = 0.011). In the multivariate analysis the PLR was not a prognostic factor in either of the two cohorts (HR = 0.92, p < 0.001 and HR = 0.89, p = 0.789, respectively). The platelet count is a valuable prognostic marker for the survival in patients both with CRC and mCRC while the PLR is not prognostic in either group.

[Simplified, low-cost gene expression profiling for the prediction of outcome in breast cancer based on routine histologic specimens]

BACKGROUND

Grade 2 breast carcinomas do not form a uniform prognostic group.

AIM

To extend the number of patients and the investigated genes of a previously identified prognostic signature described by the authors that reflect chromosomal instability in order to refine characterization of grade 2 breast cancers and identify driver genes.

METHODS

Using publicly available databases, the authors selected 9 target and 3 housekeeping genes that are capable to divide grade 2 breast carcinomas into prognostic groups. Gene expression was investigated by polymerase chain reaction in 249 formalin-fixed, paraffin-embedded breast tumors. The results were correlated with relapse-free survival.

RESULTS

Histologically grade 2 carcinomas were split into good and a poor prognosis groups. Centroid-based ranking showed that 3 genes, FOXM1, TOP2A and CLDN4 were able to separate the good and poor prognostic groups of grade 2 breast carcinomas.

CONCLUSION

Using appropriately selected control genes, a limited set of genes is able to split prognostic groups of breast carcinomas independently from their grade.

Complete genes may pass from food to human blood

Our bloodstream is considered to be an environment well separated from the outside world and the digestive tract. According to the standard paradigm large macromolecules consumed with food cannot pass directly to the circulatory system. During digestion proteins and DNA are thought to be degraded into small constituents, amino acids and nucleic acids, respectively, and then absorbed by a complex active process and distributed to various parts of the body through the circulation system. Here, based on the analysis of over 1000 human samples from four independent studies, we report evidence that meal-derived DNA fragments which are large enough to carry complete genes can avoid degradation and through an unknown mechanism enter the human circulation system. In one of the blood samples the relative concentration of plant DNA is higher than the human DNA. The plant DNA concentration shows a surprisingly precise log-normal distribution in the plasma samples while non-plasma (cord blood) control sample was found to be free of plant DNA.

Implementing an online tool for genome-wide validation of survival-associated biomarkers in ovarian-cancer using microarray data from 1287 patients

The validation of prognostic biomarkers in large independent patient cohorts is a major bottleneck in ovarian cancer research. We implemented an online tool to assess the prognostic value of the expression levels of all microarray-quantified genes in ovarian cancer patients. First, a database was set up using gene expression data and survival information of 1287 ovarian cancer patients downloaded from Gene Expression Omnibus and The Cancer Genome Atlas (Affymetrix HG-U133A, HG-U133A 2.0, and HG-U133 Plus 2.0 microarrays). After quality control and normalization, only probes present on all three Affymetrix platforms were retained (n=22,277). To analyze the prognostic value of the selected gene, we divided the patients into two groups according to various quantile expressions of the gene. These groups were then compared using progression-free survival (n=1090) or overall survival (n=1287). A Kaplan-Meier survival plot was generated and significance was computed. The tool can be accessed online at www.kmplot.com/ovar. We used this integrative data analysis tool to validate the prognostic power of 37 biomarkers identified in the literature. Of these, CA125 (MUC16; P=3.7×10(-5), hazard ratio (HR)=1.4), CDKN1B (P=5.4×10(-5), HR=1.4), KLK6 (P=0.002, HR=0.79), IFNG (P=0.004, HR=0.81), P16 (P=0.02, HR=0.66), and BIRC5 (P=0.00017, HR=0.75) were associated with survival. The combination of several probe sets can further increase prediction efficiency. In summary, we developed a global online biomarker validation platform that mines all available microarray data to assess the prognostic power of 22,277 genes in 1287 ovarian cancer patients. We specifically used this tool to evaluate the effect of 37 previously published biomarkers on ovarian cancer prognosis.

Parallel evolution under chemotherapy pressure in 29 breast cancer cell lines results in dissimilar mechanisms of resistance

Background

Developing chemotherapy resistant cell lines can help to identify markers of resistance. Instead of using a panel of highly heterogeneous cell lines, we assumed that truly robust and convergent pattern of resistance can be identified in multiple parallel engineered derivatives of only a few parental cell lines.

Methods

Parallel cell populations were initiated for two breast cancer cell lines (MDA-MB-231 and MCF-7) and these were treated independently for 18 months with doxorubicin or paclitaxel. IC50 values against 4 chemotherapy agents were determined to measure cross-resistance. Chromosomal instability and karyotypic changes were determined by cytogenetics. TaqMan RT-PCR measurements were performed for resistance-candidate genes. Pgp activity was measured by FACS.

Results

All together 16 doxorubicin- and 13 paclitaxel-treated cell lines were developed showing 2–46 fold and 3–28 fold increase in resistance, respectively. The RT-PCR and FACS analyses confirmed changes in tubulin isofom composition, TOP2A and MVP expression and activity of transport pumps (ABCB1, ABCG2). Cytogenetics showed less chromosomes but more structural aberrations in the resistant cells.

Conclusion

We surpassed previous studies by parallel developing a massive number of cell lines to investigate chemoresistance. While the heterogeneity caused evolution of multiple resistant clones with different resistance characteristics, the activation of only a few mechanisms were sufficient in one cell line to achieve resistance.

RecurrenceOnline: an online analysis tool to determine breast cancer recurrence and hormone receptor status using microarray data

In the last decades, several gene expression-based predictors of clinical behavior were developed for breast cancer. A common feature of these is the use of multiple genes to predict hormone receptor status and the probability of tumor recurrence, survival or response to chemotherapy. We developed an online analysis tool to compute ER and HER2 status, Oncotype DX 21-gene recurrence score and an independent recurrence risk classification using gene expression data obtained by interrogation of Affymetrix microarray profiles. We implemented rigorous quality control algorithms to promptly exclude any biases related to sample processing, hybridization and scanning. After uploading the raw microarray data, the system performs the complete evaluation automatically and provides a report summarizing the results. The system is accessible online at http://www.recurrenceonline.com . We validated the system using data from 2,472 publicly available microarrays. The validation of the prediction of the 21-gene recurrence score was significant in lymph node negative patients (Cox-Mantel, P = 5.6E-16, HR = 0.4, CI = 0.32-0.5). A correct classification was obtained for 88.5% of ER- and 90.5% of ER + tumors (n = 1,894). The prediction of recurrence risk in all patients by using the mean of the independent six strongest genes (P < 1E-16, HR = 2.9, CI = 2.5-3.3), of the four strongest genes in lymph node negative ER positive patients (P < 1E-16, HR = 2.8, CI = 2.2-3.5) and of the three genes in lymph node positive patients (P = 3.2E-9, HR = 2.5, CI = 1.8-3.4) was highly significant. In summary, we integrated available knowledge in one platform to validate currently used predictors and to provide a global tool for the online determination of different prognostic parameters simultaneously using genome-wide microarrays.

[From project-based sample collection to biobank]

The research group takes samples for molecular genetical examinations from tumors removed during operations within ischemic time interval. Samples are stored in liquid nitrogen. Clinical data of these patients are recorded in an informatics system developed by the group. Patients are followed in an out-patient clinic set up for this purpose not financed by the National Health Insurance Fund. Tissue samples and follow up data are used to cooperate with molecular genetical laboratories.

Effect of a tyrosine 155 to phenylalanine mutation of protein kinase cdelta on the proliferative and tumorigenic properties of NIH 3T3 fibroblasts

Tyrosine phosphorylation has emerged as an important mechanism in the regulation of enzyme function. In this paper, we describe a mutant of PKCdelta altered at a single tyrosine residue which has the opposite effect compared with wild-type PKCdelta on the growth characteristics of NIH 3T3 cells. Overexpression of wild-type PKCdelta results in a decreased growth rate and a lower cell density at confluency. On the other hand, overexpression of PKCdelta with a mutation from tyrosine to phenylalanine at position 155 results in a significantly higher rate of growth and a higher density at confluency compared with vector controls. Moreover, these cells are able to grow in soft agar and to form tumors in nude mice. In contrast to kinase negative PKC constructs, this mutant maintains in vitro kinase activity and shows a subcellular localization and a translocation pattern that are similar to those of the wild-type PKCdelta. Whether the altered biological effect is due to the missing phosphorylation on tyrosine or the mutation from tyrosine to phenylalanine per se remains under investigation.

Deletion of the sep1(+) forkhead transcription factor homologue is not lethal but causes hyphal growth in Schizosaccharomyces pombe

sep1(+), the Schizosaccharomyces pombe homologue of the forkhead/HNF-3 transcription factors, plays a role in the cell separation at the end of mitosis. Its inactivation by interruption of the coding region is not lethal but renders the sister cells unable to separate and causes hyphal growth. The persistence of unsplit septa indirectly interferes with the establishment of new cell polarity by preventing cell growth at cell tips. Temporal changes in the transcription of sep1(+) correlate with the cell cycle progression showing maximal expression at the peak of cell plate index in synchronized cultures. The constitutive overexpression of sep1(+) has no discernible effect on the morphology and physiology of the cells.

Comparison of the roles of the C1a and C1b domains of protein kinase C alpha in ligand induced translocation in NIH 3T3 cells

To explore the relative roles of the two C1 domains of protein kinase C alpha (PKC alpha) in the response to phorbol esters and related analogs, we mutated the individual C1 domains, expressed the mutated PKC alpha in NIH 3T3 cells, and then examined the ability of ligands to induce its translocation to the membrane. The C1a and C1b domains play equivalent roles for translocation in response to phorbol 12-myristate 13-acetate, mezerein, and (-)octylindolactam V. These results contrast with those previously reported for PKC delta, suggesting that the domains play different roles in different PKC isoforms.

Differential selectivity of ligands for the C1a and C1b phorbol ester binding domains of protein kinase Cdelta: possible correlation with tumor-promoting activity

Protein kinase C (PKC) represents the major, high-affinity receptor for the phorbol esters as well as for a series of structurally diverse natural products. The phorbol esters function by binding to the tandem C1a and C1b domains in PKC, leading to enzyme activation. Although the typical phorbol esters represent the paradigm for tumor promoters in mouse skin, it is now clear that different high affinity ligands for PKC have distinct biological effects. Thus, the daphnane analogue mezerein is a second-stage promoter, the macrolide bryostatin 1 is a partial antagonist, and certain 12-deoxyphorbol 13-monoesters also function as partial antagonists but with a different pattern of activity. The biochemical basis for these differences is an area of active investigation. In this report, we have examined the relative interaction of ligands differing in structure and pattern of biological response with the C1a and C1b domains of PKCdelta. We mutated either or both of the C1 domains of PKCdelta, expressed the constructs in NIH 3T3 cells, and monitored the interaction of the ligands by their ability to induce translocation of the mutated PKCdelta from the cytosol to the particulate fraction. We found that different ligands showed different dependence on the C1a and C1b domains for translocation. Whereas phorbol 12-myristate 13-acetate and the indole alkaloids indolactam and octylindolactam were selectively dependent on the C1b domain, selectivity was not observed for mezerein, for the 12-deoxyphorbol 13-monoesters prostratin or 12-deoxyphorbol 13-phenylacetate, or for the macrocyclic lactone bryostatin 1. Provocatively, the pattern of response corresponds with the activity of the compounds as complete tumor promoters.

Both the catalytic and regulatory domains of protein kinase C chimeras modulate the proliferative properties of NIH 3T3 cells

Protein kinase C (PKC) isozymes exhibit important differences in terms of their regulation and biological functions. Not only may some PKC isoforms be active and others not for a given response, but the actions of different isoforms may even be antagonistic. In NIH 3T3 cells, for example, PKCdelta arrests cell growth whereas PKCepsilon stimulates it. To probe the contribution of the regulatory and the catalytic domains of PKC isozymes to isozyme-specific responses, we prepared chimeras between the regulatory and the catalytic domains of PKCalpha, -delta, and -epsilon. These chimeras, which preserve the overall structure of the native PKC enzymes, were stably expressed in mouse fibroblasts. A major objective was to characterize the growth properties of the cells that overexpress the various PKC constructs. Our data demonstrate that both the regulatory and the catalytic domains play roles in cell proliferation. The regulatory domain of PKCepsilon enhanced cell growth in the absence or presence of phorbol 12-myristate 13-acetate (PMA), and, in the presence of PMA, all chimeras with the PKCepsilon regulatory domain also gave rise to colonies in soft agar; the role of the catalytic domain of PKCepsilon was evident in the PMA-treated cells that overexpressed the PKC chimera containing the delta regulatory and the epsilon catalytic domains (PKCdelta/epsilon). The important contribution of the PKCepsilon catalytic domain to the growth of PKCdelta/epsilon-expressing cells was also evident in terms of a significantly increased saturation density in the presence of PMA, their formation of foci upon PMA treatment, and the induction of anchorage-independent growth. Aside from the growth-promoting effect of PKCepsilon, we have shown that most chimeras with PKCalpha and -delta regulatory domains inhibit cell growth. These results underscore the complex contributions of the regulatory and catalytic domains to the overall behavior of PKC.

The catalytic domain of protein kinase C chimeras modulates the affinity and targeting of phorbol ester-induced translocation

Emerging evidence suggests important differences among protein kinase C (PKC) isozymes in terms of their regulation and biological functions. PKC is regulated by multiple interdependent mechanisms, including enzymatic activation, translocation of the enzyme in response to activation, phosphorylation, and proteolysis. As part of our ongoing studies to define the factors contributing to the specificity of PKC isozymes, we prepared chimeras between the catalytic and regulatory domains of PKCalpha, -delta, and -epsilon. These chimeras, which preserve the overall structure of the native PKC enzymes, were stably expressed in NIH 3T3 fibroblasts. Their intracellular distribution was similar to that of the endogenous enzymes, and they responded with translocation upon treatment with phorbol 12-myristate 13-acetate (PMA). We found that the potency of PMA for translocation of the PKCalpha/x chimeras from the soluble fraction was influenced by the catalytic domain. The ED50 for translocation of PKCalpha/alpha was 26 nM, in marked contrast to the ED50 of 0.9 nM in the case of the PKCalpha/epsilon chimera. In addition to this increase in potency, the site of translocation was also changed; the PKCalpha/epsilon chimera translocated mainly into the cytoskeletal fraction. PKCx/epsilon chimeras displayed twin isoforms with different mobilities on Western blots. PMA treatment increased the proportion of the higher mobility isoform. The two PKCx/epsilon isoforms differed in their localization; moreover, their localization pattern depended on the regulatory domain. Our results emphasize the complex contributions of the regulatory and catalytic domains to the overall behavior of PKC.

Protein kinase C epsilon subcellular localization domains and proteolytic degradation sites. A model for protein kinase C conformational changes

Protein kinase C (PCK) epsilon has been found to have unique properties among the PCK isozymes in terms of its membrane association, oncogenic potential, and substrate specificity. Recently we have demonstrated that PKC epsilon localizes to the Golgi network via its zinc finger domain and that both the holoenzyme and its zinc finger region modulate Golgi function. To further characterize the relationship between the domain organization and the subcellular localization of PKC epsilon, a series of NIH 3T3 cell lines were created, each overexpressing a different truncated version of PKC epsilon. The overexpressed proteins each were designed to contain an epsilon-epitope tag peptide at the COOH terminus to allow ready detection with an antibody specific for the tag. The subcellular localization of the recombinant proteins was analyzed by in vivo phorbol ester binding, immunocytochemistry, and cell fractionation followed by immunoblotting. Results revealed several regions of PKC epsilon that contain putative subcellular localization signals. The presence either of the hinge region or of a 33-amino-acid region including the pseudosubstrate sequence in the recombinant proteins resulted in association with the plasma membrane and cytoskeletal components. The catalytic domain was found predominantly in the cytosolic fraction. The accessibility and thus the dominance of these localization signals is likely to be affected by the overall conformation of the recombinant proteins. Regions with putative proteolytic degradation sites also were identified. The susceptibility of the overexpressed proteins to proteolytic degradation was dependent on the protein conformation. Based on these observations, a model depicting the interaction and hierarchy of the suspected localization signals and proteolytic degradation sites is presented.

Effect of cis-diaminedichloroplatinum (II) (cis-DDP) on the intracellular Na+/K(+)-ratio in K 562 leukemia cells as revealed by X-ray microanalysis

Changes of intracellular ionic homeostasis are believed to play a role in the cytostatic action of cis-DDP. It has been observed by means of X-ray microanalysis that cis-DDP did not alter the intracellular Na+/K(+)-ratio of K 562 leukemia cells during incubation periods which lasted shorter than the average doubling time of the cells of nearly 15 h. After 24 h the treated cells displayed at least two main populations in the distribution histogram of the Na+/K(+)-ratio. The results indicated that the passage of cis-DDP through the plasma membrane by itself did not change the monovalent electrolyte balance at the early stage of its action in K 562 cells.

The effect of idebenone on the passive K+ and Rb+ permeability of the brain cell membranes of CFY rats as revealed by the Rb+-discrimination ratio

Rubidium (Rb(+)) uptake and release of brain cortical neurons of adult (12-15 month old), normal, female CFY rats were studied in placebo- and idebenone-treated animals. Treatment period was up to 5 weeks, with 50 mg/kg bw/day idebenone (oxidized form) suspended in 5% gum arabic (verum-group), or only with the latter solvent (placebo-group). Rb(+) can replace up to 60% of the intracellular K(+), and can be used as a tracer of the K(+) movement across the cell membrane. Loading with RbCI was performed from the 3rd week of the idebenone treatment by daily intraperitoneal injections of a dose of 300 mg/kg bw, for 14 days. During the subsequent Rb(+)-release period, the so-called Rb(+)/K(+) discrimination ratio (DR) (Relman et al., 1957, J. Clin. Invest., 36, 1249) was determined on the 3rd and 8th days. Rb(+) and K(+) contents were measured by means of bulk specimen X-ray microanalysis in the intracellular water of brain cells and by atomic absorption spectrophotometry in the serum, in 3-4 animals per group, whereas these concentrations in the cerebrospinal fluid were calculated on the basis of known serum/liquor distribution factors. Normal aging causes a marked increase of DR in brain and liver cells. The values of DR obtained in both placebo and verum groups were identical with those of the age-matched, completely untreated controls. It is important to stress that the subacute idebenone treatment did not cause any deterioration of this parameter, i.e., under the given conditions idebenone does not affect the cell membrane passive Rb(+) and K(+) permeability characteristics in the neurons of adult, normal, female CFY rats.

The effect of idebenone on the total content and solubility characteristics of proteins and osmometric behavior of the intracellular mass in brain of CFY and SHRsp rats

Female CFY rats (21 months old) and male spontaneously hypertensive, stroke-prone (SHRsp) rats (3 months old), in conventional housing conditions, received placebo (5% gum arabic solution) or 50 mg/kg bw/day idebenone suspended in 5% gum arabic, through a gastric tube for 5 weeks; then their brains were elaborated as follows: (1) Total proteins as well as water-soluble and water-insoluble proteins (WSP and WIP, respectively) were separated from the brain homogenate by centrifugation at 500 X g. The WIP fractions were tested also in vitro by heat denaturation at 64 degrees C (10 min) and by 3 M urea treatment. In the placebo group of CFY rats the total protein content was 113.9 mg per g fresh weight. WIP amounted to 27.2% of the total proteins. Idebenone-treatment did not alter the protein composition in these old rats. In the SHRsp rats the total protein content of the brain cortex was almost identical with that of the normal, Wistar-derived CFY rats of much more advanced age (about 2 years). The idebenone-treatment did not alter the protein content of the brain cortex, although the WIP content and the heat-resistant fraction of it increased significantly in this strain. (2) The osmotic potential of brain tissue was determined by measuring swelling or shrinkage velocities in Ringer solution, the osmotic concentration of which was rendered hypo- or hyperosmotic by dilution or addition of polythylene glycol (PEG 6000), respectively. Idebenone treatment exerted no effect on the osmometric properties of the brain tissue in either the normal old or the SHRsp rats.

Effects of idebenone on the intracellular water and dry mass content as well as of the intracellular monovalent ion concentrations of brain cortical cells of SHRsp rats as revealed by X-ray microanalysis

The cerebral cortex of ten male SHRsp rats kept in conventional housing conditions were studied. Starting from the age of 3 months, five animals received placebo (5% gum arabic solution) and five other rats received 50 mg/kg idebenone suspended in the gum arabic, through a gastric tube for 4 weeks (except Sundays). During the last 2 weeks of treatment, 0.9% NaCl was added to the drinking water. Several completely untreated SHRsp rats of various ages were also involved in these studies. Blood pressure was measured weekly on the tail by means of an appropriate instrument. Serious hypertension was observed already by the end of the second week of treatment, displaying values of 250-260 mm Hg and increased further by about 20 mm Hg during the last 2 weeks of treatment. Intracellular water, dry mass and monovalent electrolyte concentrations were measured by means of a bulk specimen X-ray microanalytic method. The brain cells contained 77+/-1% water and 23% dry mass by weight in both placebo and verum-treated groups. The intracellular Na(+) content of all the male SHRsp rats was found to be significantly higher (180-200%) in the brain cells, whereas K(+) content increased only moderately, when expressed as percent of the intracellular dry mass. Idebenone treatment, however, lowered the intracellular Na(+) content of the brain cells to a significant extent (about 20%), i.e., it improved the Na(+) tolerance of the SHRsp rats, but did not alter the blood pressure.

Effect of enzymic (collagenase) harvesting on the intracellular Na+/K+ ratio of Swiss/3T3 cells as revealed by X-ray microanalysis

Swiss/3T3 cell cultures were harvested with 0.05% collagenase and after centrifugation the pellet was prepared by the freeze-fracture/freeze-drying (FFFD) method for bulk-specimen X-ray microanalysis. Time-dependent variations in the intracellular monovalent elemental concentrations (Na+, K+ and Cl-) as well as of the Na+/K+ ratio were followed for 120 min subsequent to harvesting. The quantitative measurements revealed a very considerable increase in the intracellular Na+ and Cl- accompanied by a decrease in the K+ concentration as soon as 5 min after harvesting. The Na+/K+ ratio had increased by this time to about 1.5 on average. These changes indicate a sustained depolarization of the cell membrane. During the first 60 min this depolarization tended to normalize as demonstrated by an exponential decrease in the intracellular Na+ and Cl- and an increase in the K+ content involving a decrease in the Na+/K+ ratio. The total intracellular monovalent ion concentration remained almost constant during this post-harvesting period. These results suggest that harvesting represents a serious depolarizing stimulus to the cells, the consequences of which are restored only after 1–2h. These alterations should be taken into consideration during various experimental designs when using anchorage-dependent cell cultures.

Energy-dispersive, bulk specimen X-ray microanalytical measurement of the intracellular Na+/K+ ratio in human laryngeal tumors

Energy-dispersive X-ray microanalysis was performed on human biopsy materials taken during laryngoscopic intervention in 18 cases. The removed tissue pieces were divided into two parts. One of them was used for pathohistological studies, the other was processed for X-ray microanalysis by the freeze-fracture freeze-drying method. Of the cases investigated 4 proved to be of benign character, whereas the rest contained carcinoma planocellulare keratoides or non-keratoides. Bulk specimen energy-dispersive X-ray microanalysis of 135 cells from the benign tissue samples revealed an average Na+/K+ molar ratio of 0.13 +/- 0.01 (SEM) in the intracellular space, with a regular Gaussian distribution. In the cases of carcinomas 641 cells were measured, the average of the same ratio was 0.67 +/- 0.03 (SEM) due mostly to an increase in the Na+ content. The distribution of data was apparently not normal in the cancerous samples. These observations and some theoretical considerations support the notion that the intracellular Na+/K+ ratio correlates with the proliferative capacity of tissues. The relevance of some recent biochemical results is also discussed in this respect.