Markers associated with genomic instability, immunogenicity and immune therapy responsiveness in Metaplastic carcinoma of the breast: Expression of γH2AX, pRPA2, P53, PD-L1 and tumor infiltrating lymphocytes in 76 cases

BACKGROUND

Metaplastic breast cancer (MpBC) is an aggressive subtype of breast carcinoma that is often resistant to conventional chemotherapy. Therefore, novel treatment strategies are urgently needed. Immune check point inhibitors have shown activity in programmed death-ligand 1 (PD-L1) - positive metastatic triple negative breast carcinoma (TNBC), which raises the possibility that immunotherapy may also be effective in MpBC as most of the MpBCs are triple negative. The aim of the present study was to assess genomic instability and immunogenicity in tumor specimens of patients with MpBC.

METHODS

A total of 76 patients diagnosed with MpBC over a 15-year period were included in the study. We performed immunohistochemical analyses for tumor cell PD-L1, immune cell PD-L1 and p53 on tissue microarrays (TMAs), analyzed stromal and intratumoral tumor infiltrating lymphocytes (TILs) from hematoxylin and eosin-stained (H&E) slides and scored gamma-H2AX (γH2AX) and phosphorylated-RPA2 (pRPA2) from whole tissue sections. We correlated marker expression with clinicopathologic features and clinical outcome.

RESULTS

All tumors expressed γH2AX and pRPA2 with median expressions of 43% and 44%. P53- (68%), tumor cell PD-L1- (59%) and immune cell PD-L1-positivity (62%) were common in MpBCs. Median stromal TIL and intratumoral TIL counts were 5% and 0. The spindle and squamous cell carcinomas expressed the highest levels of PD-L1 and TILs, and carcinoma with mesenchymal differentiation the lowest.

CONCLUSIONS

MpBC appears to be an immunogenic cancer with high genomic instability and frequent PD-L1-positivity, implying that check point inhibitors might be effective in MpBC. Expression levels of PD-L1 and TILs varied across different histologic subtypes, suggesting that immunotherapy might be less effective in carcinoma with mesenchymal differentiation.

Return to work following meningioma surgery: a Swedish nationwide registry-based matched cohort study

Background

Meningioma is the most common primary intracranial tumor. It is usually slow growing and benign, and surgery is the main treatment modality. There are limited data on return to work following meningioma surgery. The objective of this study was to determine the patterns of sick-leave rate prior to surgery, and up to 2 years after, in patients compared to matched controls.

Methods

Data on patients ages 18 to 60 years with histologically verified intracranial meningioma between 2009 and 2015 were identified in the Swedish Brain Tumor Registry (SBTR) and linked to 3 national registries after 5 matched controls were assigned to each patient.

Results

We analyzed 956 patients and 4765 controls. One year prior to surgery, 79% of meningioma patients and 86% of controls were working (P < .001). The proportion of patients at work 2 years after surgery was 57%, in contrast to 84% of controls (P < .001). Statistically significant negative predictors for return to work in patients 2 years after surgery were high (vs low) tumor grade, previous history of depression, amount of sick leave in the year preceding surgery, and surgically acquired neurological deficits.

Conclusion

There is a considerable risk for long term sick leave 2 years after meningioma surgery. Neurological impairment following surgery was a modifiable risk factor increasing the risk for long-term sick leave. More effective treatment of depression may facilitate return to work in this patient group.

Addiction to DUSP1 protects JAK2V617F-driven polycythemia vera progenitors against inflammatory stress and DNA damage, allowing chronic proliferation

Inflammatory and oncogenic signaling converge in disease evolution of BCR–ABL-negative myeloproliferative neoplasms, clonal hematopoietic stem cell disorders characterized by gain-of-function mutation in JAK2 kinase (JAK2V617F), with highest prevalence in patients with polycythemia vera (PV). Despite the high risk, DNA-damaging inflammatory microenvironment, PV progenitors tend to preserve their genomic stability over decades until their progression to post-PV myelofibrosis/acute myeloid leukemia. Using induced pluripotent stem cells-derived CD34⁺ progenitor-enriched cultures from JAK2V617F⁺ PV patient and from JAK2 wild-type healthy control, CRISPR-modified HEL cells and patients’ bone marrow sections from different disease stages, we demonstrate that JAK2V617F induces an intrinsic IFNγ- and NF-κB-associated inflammatory program, while suppressing inflammation-evoked DNA damage both in vitro and in vivo. We show that cells with JAK2V617F tightly regulate levels of inflammatory cytokines-induced reactive oxygen species, do not fully activate the ATM/p53/p21waf1 checkpoint and p38/JNK MAPK stress pathway signaling when exposed to inflammatory cytokines, suppress DNA single-strand break repair genes’ expression yet overexpress the dual-specificity phosphatase (DUSP) 1. RNAi-mediated knock-down and pharmacological inhibition of DUSP1, involved in p38/JNK deactivation, in HEL cells reveals growth addiction to DUSP1, consistent with enhanced DNA damage response and apoptosis in DUSP1-inhibited parental JAK2V617F⁺ cells, but not in CRISPR-modified JAK2 wild-type cells. Our results indicate that the JAK2V617F⁺ PV progenitors utilize DUSP1 activity as a protection mechanism against DNA damage accumulation, promoting their proliferation and survival in the inflammatory microenvironment, identifying DUSP1 as a potential therapeutic target in PV.

Perspective: APOBEC mutagenesis in drug resistance and immune escape in HIV and cancer evolution

The apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC) mutational signature has only recently been detected in a multitude of cancers through next-generation sequencing. In contrast, APOBEC has been a focus of virology research for over a decade. Many lessons learnt regarding APOBEC within virology are likely to be applicable to cancer. In this review, we explore the parallels between the role of APOBEC enzymes in HIV and cancer evolution. We discuss data supporting the role of APOBEC mutagenesis in creating HIV genome heterogeneity, drug resistance, and immune escape variants. We hypothesize similar functions of APOBEC will also hold true in cancer.

Surgery for chronic subdural hematoma in nonagenarians: A Scandinavian population-based multicenter study

OBJECTIVE

Chronic subdural hematoma (cSDH) is a prevalent condition often seen in the elderly, with surgery being the treatment of choice when symptomatic. So far, few have explored the surgical outcomes in patients 90 years or older. The aim of this study was to investigate outcome after cSDH surgery in nonagenarians (≥90 y/o group) compared to younger adult patients (<90 y/o group).

MATERIALS

In a Scandinavian population-based cohort we conducted a retrospective review of 1,254 patients undergoing primary burr-hole procedures for cSDH between January 1, 2005 and December 31, 2010 at three neurosurgical centers. In a comparative analysis, the primary end-point was difference in hematoma recurrence rates between the ≥90 y/o and <90 y/o groups. The secondary end-points were differences in perioperative morbidity and mortality between groups.

RESULTS

75 patients were 90 years or older. There was no significant difference in recurrences resulting in reoperation between the age groups (10.7% vs 13.6%, P=.47). There was also no significant difference in overall complication rate (4.1% vs 8.1%, P=.21) or severe complications (1.4% vs 2.0%, P=.68). There were three (4.0%) perioperative deaths within 30 days in the ≥90 y/o group and 40 (3.4%) in the <90 y/o group (P=.78).

CONCLUSION

Patients 90 years or older had similar rates of recurrence, perioperative morbidity and perioperative mortality as compared to younger patients. Age alone should not be a contraindication for surgery in patients with cSDH.

SETD2 loss-of-function promotes renal cancer branched evolution through replication stress and impaired DNA repair

Defining mechanisms that generate intratumour heterogeneity and branched evolution may inspire novel therapeutic approaches to limit tumour diversity and adaptation. SETD2 (Su(var), Enhancer of zeste, Trithorax-domain containing 2) trimethylates histone-3 lysine-36 (H3K36me3) at sites of active transcription and is mutated in diverse tumour types, including clear cell renal carcinomas (ccRCCs). Distinct SETD2 mutations have been identified in spatially separated regions in ccRCC, indicative of intratumour heterogeneity. In this study, we have addressed the consequences of SETD2 loss-of-function through an integrated bioinformatics and functional genomics approach. We find that bi-allelic SETD2 aberrations are not associated with microsatellite instability in ccRCC. SETD2 depletion in ccRCC cells revealed aberrant and reduced nucleosome compaction and chromatin association of the key replication proteins minichromosome maintenance complex component (MCM7) and DNA polymerase δ hindering replication fork progression, and failure to load lens epithelium-derived growth factor and the Rad51 homologous recombination repair factor at DNA breaks. Consistent with these data, we observe chromosomal breakpoint locations are biased away from H3K36me3 sites in SETD2 wild-type ccRCCs relative to tumours with bi-allelic SETD2 aberrations and that H3K36me3-negative ccRCCs display elevated DNA damage in vivo. These data suggest a role for SETD2 in maintaining genome integrity through nucleosome stabilization, suppression of replication stress and the coordination of DNA repair.

Cytomegalovirus infection induces a stem cell phenotype in human primary glioblastoma cells: prognostic significance and biological impact

Glioblastoma (GBM) is associated with poor prognosis despite aggressive surgical resection, chemotherapy, and radiation therapy. Unfortunately, this standard therapy does not target glioma cancer stem cells (GCSCs), a subpopulation of GBM cells that can give rise to recurrent tumors. GBMs express human cytomegalovirus (HCMV) proteins, and previously we found that the level of expression of HCMV immediate-early (IE) protein in GBMs is a prognostic factor for poor patient survival. In this study, we investigated the relation between HCMV infection of GBM cells and the presence of GCSCs. Primary GBMs were characterized by their expression of HCMV-IE and GCSCs marker CD133 and by patient survival. The extent to which HCMV infection of primary GBM cells induced a GCSC phenotype was evaluated in vitro. In primary GBMs, a large fraction of CD133-positive cells expressed HCMV-IE, and higher co-expression of these two proteins predicted poor patient survival. Infection of GBM cells with HCMV led to upregulation of CD133 and other GSCS markers (Notch1, Sox2, Oct4, Nestin). HCMV infection also promoted the growth of GBM cells as neurospheres, a behavior typically displayed by GCSCs, and this phenotype was prevented by either chemical inhibition of the Notch1 pathway or by treatment with the anti-viral drug ganciclovir. GBM cells that maintained expression of HCMV-IE failed to differentiate into neuronal or astrocytic phenotypes. Our findings imply that HCMV infection induces phenotypic plasticity of GBM cells to promote GCSC features and may thereby increase the aggressiveness of this tumor.

IFNγ induces oxidative stress, DNA damage and tumor cell senescence via TGFβ/SMAD signaling-dependent induction of Nox4 and suppression of ANT2

Cellular senescence provides a biological barrier against tumor progression, often associated with oncogene-induced replication and/or oxidative stress, cytokine production and DNA damage response (DDR), leading to persistent cell-cycle arrest. While cytokines such as tumor necrosis factor-alpha (TNFα) and interferon gamma (IFNγ) are important components of senescence-associated secretome and induce senescence in, for example, mouse pancreatic β-cancer cell model, their downstream signaling pathway(s) and links with oxidative stress and DDR are mechanistically unclear. Using human and mouse normal and cancer cell models, we now show that TNFα and IFNγ induce NADPH oxidases Nox4 and Nox1, reactive oxygen species (ROS), DDR signaling and premature senescence. Unlike mouse tumor cells that required concomitant presence of IFNγ and TNFα, short exposure to IFNγ alone was sufficient to induce Nox4, Nox1 and DDR in human cells. siRNA-mediated knockdown of Nox4 but not Nox1 decreased IFNγ-induced DDR. The expression of Nox4/Nox1 required Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling and the effect was mediated by downstream activation of transforming growth factor-beta (TGFβ) secretion and consequent autocrine/paracrine activation of the TGFβ/Smad pathway. Furthermore, the expression of adenine nucleotide translocase 2 (ANT2) was suppressed by IFNγ contributing to elevation of ROS and DNA damage. In contrast to mouse B16 cells, inability of TC-1 cells to respond to IFNγ/TNFα by DDR and senescence correlated with the lack of TGFβ and Nox4 response, supporting the role of ROS induced by NADPH oxidases in cytokine-induced senescence. Overall, our data reveal differences between cytokine effects in mouse and human cells, and mechanistically implicate the TGFβ/SMAD pathway, via induction of NADPH oxidases and suppression of ANT2, as key mediators of IFNγ/TNFα-evoked genotoxicity and cellular senescence.

Glucose concentrations in blood and tissue - a pilot study on variable time lag

AIM

The aim of this pilot study was to acquire insight into the parameters of glycaemic control, especially, (1) the time delay (lag phase) between plasma and tissue glucose concentrations in relation to rise and fall in glucose levels and (2) the rate of glucose increase and decrease.

METHODS

Four healthy people (HP), 4 people with type 1diabetes (DM1) and 4 with type 2 diabetes (DM2) underwent concurrent glucose measurements by means of (1) the continuous glucose monitoring system (CGMS-Medtronic), Medtronic-Minimed, CA, USA, calibrated by the glucometer Calla, Wellion, Austria, and, (2) the Beckman II analyser to measure glucose concentrations in venous plasma. Samples were taken on 4 consecutive days in the fasting state and 4 times after consumption of 50 g glucose. Carelink Personal, MS Excel, Maple and Mat lab were applied to plot the evolution of glucose concentration and analyse the results. The time difference between increase and decrease was calculated for HP, DM 1 and DM 2.

RESULTS

In DM1and DM2, glucose tolerance testing (GTT) resulted in slower transport of glucose into subcutaneous tissue than in HP where the lag phase lasted up to 12 min. The maximum increase/decrease rates in DM1 and DM2 vs HP were 0.25 vs < 0.1 mmol/L/min.

CONCLUSION

CGMS is shown to provide reliable plasma glucose concentrations provided the system is calibrated during a steady state. The analysis of glucose change rates improves understanding of metabolic processes better than standard GTT.

Immortalised breast epithelia survive prolonged DNA replication stress and return to cycle from a senescent-like state

Mammalian cells have mechanisms to counteract the effects of metabolic and exogenous stresses, many of that would be mutagenic if ignored. Damage arising during DNA replication is a major source of mutagenesis. The extent of damage dictates whether cells undergo transient cell cycle arrest and damage repair, senescence or apoptosis. Existing dogma defines these alternative fates as distinct choices. Here we show that immortalised breast epithelial cells are able to survive prolonged S phase arrest and subsequently re-enter cycle after many days of being in an arrested, senescence-like state. Prolonged cell cycle inhibition in fibroblasts induced DNA damage response and cell death. However, in immortalised breast epithelia, efficient S phase arrest minimised chromosome damage and protected sufficient chromatin-bound replication licensing complexes to allow cell cycle re-entry. We propose that our observation could have implications for the design of drug therapies for breast cancer.

Specific lipofuscin staining as a novel biomarker to detect replicative and stress-induced senescence. A method applicable in cryo-preserved and archival tissues

There is shortage of extensive clinicopathologic studies of cellular senescence because the most reliable senescence biomarker, the detection of Senescence-Associated-beta-galactosidase activity (SA-β-gal), is inapplicable in archival material and requires snap-frozen tissues. We validated the histochemical Sudan-Black-B (SBB) specific stain of lipofuscin, an aggregate of oxidized proteins, lipids and metals, known to accumulate in aged tissues, as an additional reliable approach to detect senescent cells independently of sample preparation. We analyzed cellular systems in which senescence was triggered by replicative exhaustion or stressful stimuli, conditional knock-in mice producing precancerous lesions exhibiting senescence, and human preneoplastic lesions known to contain senescent cells. In the above settings we demonstrated co-localization of lipofuscin and SA-β-gal in senescent cells in vitro and in vivo (cryo-preserved tissue), strongly supporting the candidacy of lipofuscin for a biomarker of cellular senescence. Furthermore, cryo-preserved tissues positive for SA-β-gal were formalin-fixed, paraffin-embedded, and stained with SBB. The corresponding SA-β-gal positive tissue areas stained specifically for lipofuscin by SBB, whereas tissues negative for SA-β-gal were lipofuscin negative, validating the sensitivity and specificity of the SBB staining to visualize senescent cells in archival material. The latter unique property of SBB could be exploited in research on widely available retrospective tissue material.

Nucleoporin NUP153 guards genome integrity by promoting nuclear import of 53BP1

53BP1 is a mediator of DNA damage response (DDR) and a tumor suppressor whose accumulation on damaged chromatin promotes DNA repair and enhances DDR signaling. Using foci formation of 53BP1 as a readout in two human cell lines, we performed an siRNA-based functional high-content microscopy screen for modulators of cellular response to ionizing radiation (IR). Here, we provide the complete results of this screen as an information resource, and validate and functionally characterize one of the identified 'hits': a nuclear pore component NUP153 as a novel factor specifically required for 53BP1 nuclear import. Using a range of cell and molecular biology approaches including live-cell imaging, we show that knockdown of NUP153 prevents 53BP1, but not several other DDR factors, from entering the nuclei in the newly forming daughter cells. This translates into decreased IR-induced 53BP1 focus formation, delayed DNA repair and impaired cell survival after IR. In addition, NUP153 depletion exacerbates DNA damage caused by replication stress. Finally, we show that the C-terminal part of NUP153 is required for effective 53BP1 nuclear import, and that 53BP1 is imported to the nucleus through the NUP153-importin-β interplay. Our data define the structure-function relationships within this emerging 53BP1-NUP153/importin-β pathway and implicate this mechanism in the maintenance of genome integrity.

Differences in phenotype and disease course in adult and paediatric inflammatory bowel disease--a population-based study

BACKGROUND

Few studies have compared phenotype and disease course in children and adults with inflammatory bowel disease (IBD).

AIM

  To compare phenotype, treatment and disease course in children (<15 years) and adults (≥18 years) with IBD.

METHODS

Two population-based cohorts comprising paediatric (2001-2006) and adult (2003-2004) patients from Copenhagen County and City were studied.

RESULTS

Twenty children and 106 adults with ulcerative colitis (UC), and 29 children and 67 adults with Crohn's disease (CD) were included. Median follow-up time was 4.8 years (children) and 5.2 years (adults). Children with UC had more extensive disease compared to adult patients [14 (70%) vs. 20 (19%), P<0.001]. The risks of starting systemic steroid treatment and AZA/MP were higher for paediatric UC patients compared to adult UC patients; hazard ratio (HR): 3.1 (95% CI: 1.8-5.3) and HR: 2.5 (1.3-5-9), respectively. Steroid dependency was more frequent in paediatric than in adult UC patients [9 (45%) vs. 9 (8%), P<0.001]. Mild disease course was less frequent in children with UC compared to adult patients [7 (35%) vs. 76 (72%), P=0.002]. Paediatric and adult CD patients did not differ regarding treatment or disease course. Cumulative 5-year surgery rates for paediatric and adult patients were 5% and 9% for UC (N.S.) and 18% and 21% for CD (N.S.), respectively.

CONCLUSIONS

Paediatric UC patients had more extensive disease, were more often treated with systemic steroids and AZA, had a higher frequency of steroid dependency and a more severe disease course compared to adult UC patients. No differences were found when comparing paediatric and adult CD patients.

Multicentric breast cancer: clonality and prognostic studies

Clonality of multicentric breast cancer has traditionally been difficult to assess. We aimed to assess this using analysis of TP53 status (expression and mutation status). These results were then incorporated into an analysis of prognostic factors in multicentric tumours in a 10-year follow up study. Clonal status of multicentric breast cancer foci (n = 88 foci) was determined by immunohistochemical and molecular studies of TP53 in a total of 40 patients. Prognostic factors from these patients were also compared with 80 age- and stage-matched controls with unicentric breast cancer from the Royal Marsden NHS Foundation Trust Breast Cancer Database. Our results indicate that multicentric breast cancer foci were polyclonal within an individual patient in at least 10 patients (25%) with respect to immunohistochemical staining and in four patients (10%) with respect to abnormal band shifts on single strand conformational polymorphism (SSCP) molecular analysis. No individual variable was predictive of multicentric or unicentric disease. However, there was a worse overall survival in the multicentric breast cancer patients in whom at least two cancer foci stained positively on TP53 immunohistochemistry compared with the matched control group (P = 0.04). In conclusion, these results suggest that a proportion of multicentric breast cancer foci are polyclonal with respect to TP53 status and that TP53 over-expression predicts for a poorer prognosis in multicentric breast cancer.

Wavesense technology glucometer Linus for routine self-monitoring and clinical practice

Conventional glucometer systems for plasma/blood glucose monitoring are based on colorimetry or static electrochemistry using a fixed input signal. The recent glucometer Linus, Wellion, Agamatrix, USA, based on wavesense dynamic electrochemistry, uses a time-varying input signal to give a more accurate glucose reading. The purpose of this study was to compare the plasma glucose (PG) readings obtained by nursing staff from glucometer Linus and PG values estimated on an approved analyzer Daytona™, Randox, Global Medical Instrumentation, Inc., MN, USA. In the course of 5 weeks, 221 fingerprick capillary blood samples were taken from persons with diabetes at different times and investigated using glucometer Linus. Within two following minutes, blood from the same fingerprick was also collected in a tube and centrifuged; the plasma was analyzed on the Daytona™ analyzer. Statistical analysis was performed using the software SPSS v. 15.0, SPSS Inc., Chicago, IL, USA. A total of 221 paired PG values were plotted on the error grid diagram indicating that 218 values (98.6%) of the glucose readings (Linus vs. Daytona) were within the clinically accurate zone A (maximum difference ±20%) and 3 values (1.4%) within the acceptable zone B. Daytona showed 4 PG values <4.2 mmol/l (75 mg/dl) and their difference of respective Linus readings was always <0.83 mmol/l (15 mg/dl). Correlation of results was strong (r = 0.992). Glucometer Linus readings correspond to the ISO and FDA standards. So, Linus appears to be an accurate device for PG-self-monitoring and clinical practice.

p53-dependent G(1) arrest in 1st or 2nd cell cycle may protect human cancer cells from cell death after treatment with ionizing radiation and Chk1 inhibitors

OBJECTIVES

This study was performed to explore the strategy of combining Chk1 inhibitors with ionizing radiation (IR) to selectively target p53-deficient cancer cells.

MATERIALS AND METHODS

Survival and cell cycle progression were measured in response to IR and the Chk1 inhibitors, UCN-01 and CEP-3891, in colon carcinoma HCT116 p53+/+ and p53-/- cells, and in osteosarcoma U2OS-VP16 cells with conditional expression of dominant-negative p53 (p53DD).

RESULTS

Clonogenic survival was selectively reduced in HCT116 p53-/- compared to p53+/+ cells after treatment with UCN-01 and IR, and HCT116 p53+/+ cells also displayed strong p53-dependent G(1) arrest in the 1st cell cycle after IR. In contrast, clonogenic survival was affected similarly in U2OS-VP16 cells with and without expression of p53DD. However, death of U2OS-VP16 cells was p53 dependent as assessed by cell viability assay at 72 h, and this was associated with p53-dependent G(1) arrest in the 2nd cell cycle after treatment. Notably, HCT116 cells were overall more resistant than U2OS cells to cytotoxic effects of Chk1 inhibitors.

CONCLUSION

Our results suggest that p53-dependent G(1) arrest in both 1st and 2nd cell cycles may protect human cancer cells from cell death after treatment with IR and Chk1 inhibitors. However, a challenge for future clinical use will be that different cancers display different intrinsic sensitivity to such inhibitors.

Influence of oral antidiabetic drugs on hyperglycemic response to foods in persons with type 2 diabetes mellitus as assessed by continuous glucose monitoring system: a pilot study

BACKGROUND

The purpose of this prospective open-label trial was (1) to assess the influence of oral antidiabetic drugs (OAD) on the glycemic index (GI), glucose response curves (GRCs), daily mean plasma glucose (MPG) and (2) to compare the GI of foods in persons with OAD-treated type 2 diabetes mellitus (T2DM) with the respective GI in healthy persons (HP).

METHODS

Tested foods containing 50 g of carbohydrates were eaten for breakfast and dinner after 10 and 4 h of fasting, respectively. Glycemic index, GRC, and MPG were obtained using the CGMS System Gold (CGMS). In T2DM patients [n = 16; age (mean +/- standard error) 56.0 +/- 2.25 years], foods were tested four times: tests 1, 2, and 3 were performed within one week in which placebo was introduced on day 2, and test 4 was carried out five weeks after reintroduction of OAD. Glycemic indexes, GRC, and MPG from tests 1, 2, 3, and 4 were compared. In a control group of 20 HP (age 24.4 +/- 0.71 years), the mean GIs were calculated as the mean from 20 subject-related GIs.

RESULTS

In T2DM patients, subject-related assessment of GIs, GRC, and MPG distinguished persons with and without OAD effect. Nevertheless, the group-related GIs and the MPG on days 2, 8, and 39 showed no significant difference. There was no significant difference between the GIs in OAD-treated T2DM patients (test 4) versus HP (except in apple baby food). Glucose response curves were significantly larger in T2DM patients (test 4) versus HP.

CONCLUSIONS

Determination of GRC and subject-related GI using the CGMS appears to be a potential means for the evaluation of efficacy of OAD treatment. Further studies are underway.

Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling in human gliomas

Malignant gliomas, the deadliest of brain neoplasms, show rampant genetic instability and resistance to genotoxic therapies, implicating potentially aberrant DNA damage response (DDR) in glioma pathogenesis and treatment failure. Here, we report on gross, aberrant constitutive activation of DNA damage signalling in low- and high-grade human gliomas, and analyze the sources of such endogenous genotoxic stress. Based on analyses of human glioblastoma multiforme (GBM) cell lines, normal astrocytes and clinical specimens from grade II astrocytomas (n=41) and grade IV GBM (n=60), we conclude that the DDR machinery is constitutively activated in gliomas, as documented by phosphorylated histone H2AX (gammaH2AX), activation of the ATM-Chk2-p53 pathway, 53BP1 foci and other markers. Oxidative DNA damage (8-oxoguanine) was high in some GBM cell lines and many GBM tumors, while it was low in normal brain and grade II astrocytomas, despite the degree of DDR activation was higher in grade II tumors. Markers indicative of ongoing DNA replication stress (Chk1 activation, Rad17 phosphorylation, replication protein A foci and single-stranded DNA) were present in GBM cells under high- or low-oxygen culture conditions and in clinical specimens of both low- and high-grade tumors. The observed global checkpoint signaling, in contrast to only focal areas of overabundant p53 (indicative of p53 mutation) in grade II astrocytomas, are consistent with DDR activation being an early event in gliomagenesis, initially limiting cell proliferation (low Ki-67 index) and selecting for mutations of p53 and likely other genes that allow escape (higher Ki-67 index) from the checkpoint and facilitate tumor progression. Overall, these results support the potential role of the DDR machinery as a barrier to gliomagenesis and indicate that replication stress, rather than oxidative stress, fuels the DNA damage signalling in early stages of astrocytoma development.

Benefits of three-month continuous glucose monitoring for persons with diabetes using insulin pumps and sensors

BACKGROUND

The latest Paradigm 722 insulin pump, Medtronic MiniMed, USA, enables daily reading of 288 interstitial fluid glucose concentrations determined by a sensor inserted into subcutaneous tissue; the sensor signals are transmitted into the insulin pump, enabling the patient to see real-time glucose concentration on the display and adapt further treatment.

AIMS

To assess the evolution of HbA1c over the course of a 3-month period in two cohorts of persons with type 1 (n=39) or type 2 (n=3) diabetes (PWD): 1) PWD on Paradigm 722 using sensors for continuous glucose monitoring (CGM group), 2) PWD on other types of insulin pumps performing intensive self-monitoring as before (3 to 6 times/d) on glucometer Linus, Wellion, Agamatrix (control group).

METHODS

Compliant PWDs using insulin pump with insulin aspart for several previous months were included in the study. Seventeen were put on Paradigm 722 with CGM and 25 were included in the control group. Paired t-test and the statistical program SPSS v.15.0 were used to analyze the data.

RESULTS

There was no significant difference in age between the two groups (P=0.996), in diabetes duration (P=0.482) or in daily insulin dose (P=0.469). In the CGM group (but not in the control group) HbA1c/IFCC dropped from 6.98+/-0.43 % to 5.98+/-0.36 % (P=0.006) within 1 month and remained reduced.

CONCLUSION

The use of the Paradigm 722 insulin pump with CGM resulted in significant improvement in HbA1c which appeared within one month and remained throughout the whole 3-month study period. No significant improvement in HbA1c was seen in the control group.

Resistin - concentrations in persons with type 2 diabetes mellitus and in individuals with acute inflammatory disease

Resistin is a recently discovered signal molecule, which could help elucidation of the pathophysiology of the insulin resistance and its correlation with obesity. As little information was available about resistin determination in venous blood at the time of our study, we focused on the question whether any correlation exists between persons with type 2 diabetes mellitus, with systemic inflammation, healthy persons and resistin concentrations and laboratory markers of inflammation, peptone, BMI. Differences of resistin values in these types of volunteers were studied as well.

METHODS

Persons under study were divided into 3 groups: group A - with clinical signs of inflammatory disease of respiratory tract, leukocytosis > 10000/ul and CRP concentration > 50 mg/l (n = 35); group B - with well controlled type 2 DM treated by oral antidiabetic drugs, without clinical signs of inflammation and negative case history of acute disease (n = 12); group C - without clinical signs of inflammation and negative case history of acute disease (n = 77). For all volunteers we determined BMI index and examined resistin, leptin, interleukin 6, TNF-alpha, Na, K, Cl, insulin, cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerols, creatinine, uric acid, ALT, AST, GMT, P, Mg and albumin in serum.

RESULTS

Persons with clinical signs of severe inflammation had higher concentrations of Il6, CRP, resistin and a markedly lower BMI, decreased values of glucose, sodium, triacylglycerols, cholesterol, LDL-cholesterol and HDL-cholesterol compared to diabetics of type 2 (p < 0.05). Persons with clinical signs of severe inflammation showed significantly higher concentrations of TNF-alpha, Il6, CRP, resistin, glucose, leptin and considerably lower values of albumin, sodium and HDL-cholesterol than healthy individuals (p < 0.05). Persons with type 2 DM had markedly higher values of BMI, CRP, glucose, triacylglycerols, LDL-cholesterol, GMT and leptin, compared to healthy volunteers (p < 0.05). None of the three groups differed markedly in age or sex. Healthy volunteers show a significant correlation between leptin and resistin (correlation coefficient 0.82); this correlation was not found in patients with inflammation and type 2 DM. The group of volunteers with inflammations was found to have a significant positive correlation between resistin and inflammatory markers (correlation coefficient 0.3-0.5), negative correlation between resistin and cholesterol. We also found positive correlations between leptin and BMI as well as negative correlations between leptin and CRP. No significant correlations between resistin and other studied parameters were found in persons with type 2 DM.

CONCLUSION

In healthy population a correlation was found between leptin and resistin concentrations in serum. In patients with severe inflammatory disease a correlation between resistin concentration and laboratory markers of inflammation was shown, however, no correlation was found between leptin and resistin. Resistin concentration in the serum of these patients is significantly higher ( p < 0.01) compared to healthy subjects and well controlled persons with type 2 DM with signs of insulin resistance. This may be due to a direct effect of inflammatory cytokines on resistin production. In persons with type 2 DM no significant correlations were found between resistin and other individual parameters ( insulin sensitivity markers, BMI or leptin). Resistin concentrations in persons with type 2 DM do not differ from concentrations of common population.

Urinary clusterin concentrations--a possible marker of nephropathy? Pilot study

BACKGROUND

Clusterin is a glycoprotein which participates in a number of pathophysiological processes in the organism. Information about clusterin use in the diagnosis of nephropathy and the differential diagnosis of proteinuria has been published recently.

AIM

Search for correlations between urinary clusterin concentration and other renal function markers. Evaluation of urinary clusterin measurement use in the differential diagnosis of nephropathy.

METHODS

Urea, creatinine, IgG, transferin, Na, K in serum and 24-hour collected urine were measured in a sample of 82 individuals. Cystatin C in sera was also measured as were GMT, alpha-1 microglobulin, albumin, total protein in urine. In all probands urinary clusterin was assayed (ELISA).

RESULTS

Urinary clusterin values correlated with urinary total protein concentrations (r = 0.28; p = 0.018), total protein/creatinine index (r = 0.26; p = 0.02). No correlation was found between urine clusterin concentration and glomerular filtration rate, age, urine GMT/creatinine, alpha-1-microglobulin, urine albumin and albumin/creatinine ratio or Na, K fractional excretions. We found no urinary clusterin differences by sex of probands. No evidence of any relationship between urine clusterin and presence of defect of renal function, number of risk factors (chi(2) = 16.0; DF = 15; p = 0.38), albumin/creatinine index (chi(2) = 0.76; DF = 3; p = 0,86), total protein/creatinine (chi(2) = 6.5; DF = 3; p = 0.09), GMT/creatinine (chi(2) = 2.3; DF = 3; p = 0.51), high urinary alpha-1-microglobulin (chi(2) = 4.1; DF = 3; p = 0.25) or decreased of GFR (chi(2) = 1.3; DF = 3; p = 0.74).

CONCLUSIONS

A positive correlation exists between urinary clusterin and urinary total protein and total protein/ creatinine index. Urinary clusterin measurement with ELISA test does not offer any advantage over routinely used parameters for nephropathy diagnosis and the differential diagnosis of proteinuria type.

DNA damage signalling guards against activated oncogenes and tumour progression

DNA damage response (DDR), the guardian of genomic integrity, emerges as an oncogene-inducible biological barrier against progression of cancer beyond its early stages. Recent evidence from both cell culture and animal models as well as analyses of clinical specimens show that activation of numerous oncogenes and loss of some tumour suppressors result in DNA replication stress and DNA damage that alarm the cellular DDR machinery, a multifaceted response orchestrated by the ATR-Chk1 and ATM-Chk2 kinase signalling pathways. Such activation of the DDR network leads to cellular senescence or death of oncogene-transformed cells, resulting in delay or prevention of tumorigenesis. At the same time, the ongoing chronic DDR activation creates selective pressure that eventually favours outgrowth of malignant clones with genetic or epigenetic defects in the genome maintenance machinery, such as aberrations in the ATM-Chk2-p53 cascade and other DDR components. Furthermore, the executive DDR machinery is shared by at least two anticancer barriers, as both the oncogene-induced DNA replication stress and telomere shortening impact the cell fate decisions through convergence on DNA damage signalling. In this study, we highlight recent advances in this rapidly evolving area of cancer research, with particular emphasis on mechanistic insights, emerging issues of special conceptual significance and discussion of major remaining challenges and implications of the concept of DDR as a tumorigenesis barrier for experimental and clinical oncology.

Automated computation of glycemic index for foodstuffs using continuous glucose monitoring

BACKGROUND

The glycemic index (GI) is a measure of the ability of a food to raise glucose levels after it is eaten. Continuous glucose monitoring (CGM) has been shown to give identical values of GI when compared to traditional methods. However, there has been no standardized protocol for measuring GI that takes into account interindividual variability and chronophysiological glycemic response to food. Our aim was (1) to create and describe software based on a Microsoft Excel 2000 spreadsheet to facilitate rapid, automated, accurate, and standardized processing of data obtained using recent CGM methodology to measure GI and its variability and (2) to assess the benefits of this new approach.

METHOD

Twenty healthy subjects consumed 50 grams of glucose or four alternative foodstuffs (chocolate, apple baby food, rice squares, or yogurt) at breakfast and dinner during 1 week, resulting in 300 CGMS glucose profiles; 92% of meal tests were satisfactory for evaluation. Application and functions of the software DegifXL are described.

RESULTS

Using the new spreadsheet software DegifXL, time required for data processing for the 15 data sets for each subject was reduced from 2000 to 160 minutes relative to previously used manual methods. We characterized the GI for four foodstuffs with three replicate measurements in each of 20 subjects and evaluated between person, between time period, and between replicate GI variabilities.

CONCLUSION

DegifXL, combined with CGM, was an efficient and effective tool for routine measurement of group- and subject-related GI.

The DNA damage signalling kinase ATM is aberrantly reduced or lost in BRCA1/BRCA2-deficient and ER/PR/ERBB2-triple-negative breast cancer

The ataxia-telangiectasia-mutated (ATM) kinase is a key transducer of DNA damage signals within the genome maintenance machinery and a tumour suppressor whose germline mutations predispose to familial breast cancer. ATM signalling is constitutively activated in early stages of diverse types of human malignancies and cell culture models in response to oncogene-induced DNA damage providing a barrier against tumour progression. As BRCA1 and BRCA2 are also components of the genome maintenance network and their mutations predispose to breast cancer, we have examined the ATM expression in human breast carcinomas of BRCA1/2 mutation carriers, sporadic cases and familial non-BRCA1/2 patients. Our results show that ATM protein expression is aberrantly reduced more frequently among BRCA1 (33%; P=0.0003) and BRCA2 (30%; P=0.0009) tumours than in non-BRCA1/2 tumours (10.7%). Furthermore, the non-BRCA1/2 tumours with reduced ATM expression were more often estrogen receptor (ER) negative (P=0.0002), progesterone receptor (PR) negative (P=0.004) and were of higher grade (P=0.0004). In our series of 1013 non-BRCA1/2 cases, ATM was more commonly deficient (20%; P=0.0006) and p53 was overabundant (47%; P<0.0000000001) among the difficult-to-treat ER/PR/ERBB2-triple-negative subset of tumours compared with cases that expressed at least one of these receptors (10 and 16% of aberrant ATM and p53, respectively). We propose a model of 'conditional haploinsufficiency' for BRCA1/2 under conditions of enhanced DNA damage in precancerous lesions resulting in more robust activation and hence increased selection for inactivation or loss of ATM in tumours of BRCA1/2 mutation carriers, with implications for genomic instability and curability of diverse subsets of human breast cancer.

DNA damage response in human testes and testicular germ cell tumours: biology and implications for therapy

DNA damage response (DDR) is emerging as a physiological anti-cancer barrier in early stages of cancer development, as shown for several types of solid cancers derived from somatic cells. Here we discuss our recently published and unpublished results on the exceptional paucity of such constitutive activation of the DDR machinery in human testicular germ cell tumours (TGCTs), including their common pre-invasive stage of carcinoma in situ (CIS). Our conclusions are supported by immunohistochemical analyses of multiple markers of activated DNA damage signalling, such as the phosphorylated ATM and Chk2 checkpoint kinases and phosphorylated histone H2AX. We propose that the unique lack of DDR activation in TGCTs reflects the biology of their cell of origin, the gonocyte. Furthermore, we propose that the lack of DDR activation avoids the pressure to select for mutations in DDR genes such as p53 or ATM, and the resulting intact DDR machinery may have implications for the exceptional curability of TGCTs by DNA damaging therapies.

DNA damage response mediators MDC1 and 53BP1: constitutive activation and aberrant loss in breast and lung cancer, but not in testicular germ cell tumours

MDC1 and 53BP1 are critical components of the DNA damage response (DDR) machinery that protects genome integrity and guards against cancer, yet the tissue expression patterns and involvement of these two DDR adaptors/mediators in human tumours remain largely unknown. Here we optimized immunohistochemical analyses of human 53BP1 and MDC1 proteins in situ and identified their virtually ubiquitous expression, both in proliferating and quiescent, differentiated tissues. Focus formation by 53BP1 and/or MDC1 in human spermatogenesis and subsets of breast and lung carcinomas indicated physiological and 'pathological' activation of the DDR, respectively. Furthermore, aberrant reduction or lack of either protein in significant proportions of carcinomas supported the candidacy of 53BP1 and MDC1 for tumour suppressors. Contrary to carcinomas, almost no activation or loss of MDC1 or 53BP1 were found among testicular germ-cell tumours (TGCTs), a tumour type with unique biology and exceptionally low incidence of p53 mutations. Such concomitant presence (in carcinomas) or absence (in TGCTs) of DDR activation and DDR aberrations supports the roles of MDC1 and 53BP1 within the ATM/ATR-regulated checkpoint network which, when activated, provides an early anti-cancer barrier the pressure of which selects for DDR defects such as p53 mutations or loss of 53BP1/MDC1 during cancer progression.

Centrosome abnormalities are frequently observed in non-small-cell lung cancer and are associated with aneuploidy and cyclin E overexpression

Centrosome abnormalities are observed in human cancers and have been associated with aneuploidy, a driving force in tumour progression. However, the exact pathways that tend to cause centrosome abnormalities have not been fully elucidated in human tumours. Using a series of 68 non-small-cell lung carcinomas and an array of in vitro experiments, the relationship between centrosome abnormalities, aneuploidy, and the status of key G1 to S-phase transition cell-cycle molecules, involved in the regulation of centrosome duplication, was investigated. Centrosome amplification and structural abnormalities were common (53%), were strongly related to aneuploidy, and, surprisingly, were even seen in adjacent hyperplastic regions, suggesting the possibility that these are early lesions in lung carcinogenesis. Cyclin E and E2F1 overexpression, but not p53 mutation, was observed to correlate with centrosome abnormalities in vivo (p = 0.029 and p = 0.015, respectively). This was further strengthened by the observation that cyclin E was specifically present in the nucleus and/or cytoplasm of the cells that contained centrosome aberrations. The cytoplasmic cyclin E signal may be attributed, in part, to the presence of truncated low-molecular-weight isoforms of cyclin E. In order to isolate the effect of cyclin E on the appearance of centrosome abnormalities, a U2OS tetracycline-repressible cyclin E cell line that has a normal centrosome profile by default was used. With this system, it was confirmed in vitro that persistent cyclin E overexpression is sufficient to cause the appearance of centrosome abnormalities.

The CHEK2 gene and inherited breast cancer susceptibility

Checkpoint kinase 2 (CHEK2, Chk2) emerges as an important signal transducer of cellular responses to DNA damage and a candidate tumor suppressor whose defects contribute to molecular pathogenesis of diverse types of human malignancies, both sporadic and hereditary. Here, we briefly outline the molecular properties, regulation and physiological role of CHEK2, and review in more detail its defects that predispose to tumors, with particular emphasis on familial breast cancer. The frequency, penetrance and epidemiological as well as clinical significance of the two most studied breast cancer-predisposing variants of the CHEK2 gene, 1100delC and I157T, are highlighted in more depth, and additional CHEK2 mutations and their cancer relevance are discussed as well. These recent findings are considered also from a broader perspective of CHEK2 as the integral component of the ataxia telangiectasia-mutated-CHEK2-p53 pathway within the genome integrity maintenance system and a barrier against tumor progression. Finally, the potential value of information about the CHEK2 status in family counseling and optimizition of individualized cancer treatment is discussed.

Function and accuracy of glucose sensors beyond their stated expiry date

BACKGROUND

The sensor of the Continuous Glucose Monitoring System (CGMS, Medtronic Minimed, Northridge, CA) is labeled to expire 6 months following its production and to measure the glucose concentration in interstitial fluid up to 3 days after insertion. The purpose of this study was to demonstrate potential possibilities of sensors when used beyond their expiry date.

METHODS

Twenty sensors, each between 3 to 18 months after the expiry date, were assessed in a 7-day period after insertion. Twenty healthy volunteers 23.4 +/- 2.92 (mean +/- SD) years old were trained in handling the CGMS and the Hypoguard (Woodbridge, UK) Advance glucometer system to measure their capillary plasma glucose concentration 18 times a day. Sensor function was estimated according to the number of readings per day, the accuracy according to the mean absolute difference (MAD), and correlation coefficient (r) between glucometer and sensor resulting from paired values.

RESULTS

Uninterrupted sensor function was found in 117 of 140 sensor-days (83.6%). A reduction of readings in 23 sensor-days (16.4%) was caused by user error (5 sensor-days, 3.6%), connecting cable (7 sensor-days, 5%), sensor failure (8 sensor-days, 5.7%), or uncertain factors (3 sensor-days, 2.1%). MAD was always < 28%, and r = 0.79.

CONCLUSIONS

Neither the expiry date nor the 3-day period of use limits the reliable function of a CGMS sensor. Sensors were found to function as long as 18 months after the expiry date, mostly for at least 7 days. There were no serious local adverse reactions. Prolongation of shelflife label and insertion time appears to be reasonable. Further studies are in progress.

Continuous Glucose Monitoring - A Novel Approach to the Determination of the Glycaemic Index of Foods (DEGIF 1)

The glycaemic index (GI) is a measure of the food power to raise plasma glucose (PG) concentration after a meal. For its determination, classical methods register the development of glucose concentration in capillary plasma or whole blood. The aim of this prospective open-label trial was to compare the GI of selected foods obtained by means of the Continuous Glucose Monitoring System (CGMS) (Minimed Medtronic, Northridge, USA) which has not been applied for this purpose until now, with the respective GI determined by a conventional method using the Glucometer Advance System (GAS) (Hypoguard, Woodbridge, United Kingdom), and to assess the advantages of each approach.

METHODS

Portions of tested foods containing 50 g of carbohydrates were eaten for breakfast and for dinner after 10 and 4 h fast, respectively, by 20 healthy volunteers. Using GAS, PG-curves were constructed from 9 PG values at time 0, 15, 30, 45, 60, 75, 90, 105 and 120 min after the meal, and, using CGMS, from 25 values of interstitial fluid glucose concentration (ISFG) stored within 120 min in 5-minute intervals in CGMS memory. The GI was calculated (for GAS and CGMS separately) by dividing the incremental area under the curve for the tested food by the average area of 3 tests performed with the standard. Having excluded tests with missing glucose values, there remained 285 GAS- and 290 CGMS tests for further analysis. In each volunteer, each food was tested 3 times within one week so that 1 to 3 GI's were obtained and averaged. The GI for each tested food was calculated as the mean from the respective average GI's of 20 volunteers. The GI-variability was assessed according to the respective SD. The preference of GAS vs. CGMS in the persons tested was explored by means of a questionnaire. MS Excel and the statistical program SPSS v. 10.1 were used to analyze the data.

RESULTS

The GI values (mean +/- SD) measured by GAS/CGMS were for dark chocolate 43.6 +/- 22.13 %/44.0 +/- 21.71 % (p > 0.01); for apple baby food 46.1 +/- 21.38 %/53.8 +/- 37.69 % (p > 0.01); for puffed rice squares 76.5 +/- 20.24 %/76.9 +/- 27.62 % (p > 0.01); for yogurt 43.2 +/- 20.17 %/37.7 +/- 21.55 % (p > 0.01). The GI's of dark chocolate, apple baby food and yogurt, determined by either method, were significantly lower than the GI of puffed rice squares (p < 0.01). CGMS was preferred by 12 of 20 volunteers (60 %).

CONCLUSIONS

No significant difference could be seen between the GI's determined by conventional method (GAS) and by CGMS (p > 0.01). The method with CGMS is reliable and comfortable for both tested persons and investigators. Hence, it appears to become a sophisticated approach to determine the GI.