Functional remodeling of perinuclear mitochondria alters nucleoplasmic Ca2+ signaling in heart failure

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): BioTechMed-Graz

Mitochondrial dysfunction in cardiomyocytes is a hallmark of heart failure (HF) development. Although initial studies recognized the importance of different mitochondrial subpopulations, there is a striking lack of direct comparison of intrafibrillar (IF) vs. perinuclear (PN) mitochondria during the development of HF.

Here, we use multiple approaches to examine the morphology and functional properties of IF vs. PN mitochondria in pressure overload-induced cardiac remodeling in mice, and in non-failing and failing human cardiomyocytes. We could demonstrate that PN mitochondria from failing cardiomyocytes are more susceptible to changes in mitochondrial membrane potential (ΔΨm), ROS generation and impairment in Ca2+ uptake compared to IF mitochondria at baseline and under physiological stress protocol. We also demonstrated, for the first time, that under normal conditions PN mitochondrial Ca2+ uptake shapes nucleoplasmic Ca2+ transients (CaTs) and prevents nucleoplasmic Ca2+ overload. Loss of PN mitochondria Ca2+ buffering capacity translates into increased nucleoplasmic CaTs and may explain disproportionate rise in nucleoplasmic [Ca2+] in failing cardiomyocytes at increased stimulation frequencies. Therefore, a previously unidentified benefit of restoring the mitochondrial Ca2+ uptake may be normalization of nuclear Ca2+ signaling and alleviation of altered excitation-transcription, which could be an important therapeutic approach to prevent adverse cardiac remodeling.

Latest Developments in the Management of Nut Allergies

Purpose of review

In this review, we sought to describe the most recent advances in the dietary and medical management of peanut and tree nut allergy, including selective introduction and immunotherapy.

Recent findings

Dietary updates include changes to labeling laws, improved information sources, and new apps for buying foods in shops and overseas to better protect individuals with nut allergies. There are still issues in the management of nut allergies in schools, such as parents having to resort to packed lunches instead of school meals and patients experiencing bullying. Air travel also poses concern, but additional resources are now available to travelers, and recent evidence suggest limited airborne exposure to nuts. The medical management of anaphylaxis is use of epinephrine; however, this remains underutilized. Needle length and administration devices have been recently debated considering the risk of bone penetration vs subcutaneous administration, and autoinjectors seem to deliver higher peak concentrations than syringes. Selective nut introduction has gained momentum in the last 5 years, demonstrating improved quality of life but with the need for motivated parents for continued consumption and available resources for challenges. Immunotherapy to nuts is also a rapidly developing field, with the balance of efficacy and safety being important considerations in the differing modes of administration.

Summary

The management of nut allergies is a rapidly developing field, and dietary and medical management have progressed significantly in the last 5 years. Future research directions include improving safety and efficacy of food immunotherapy and examining patients’ goals for therapy and treatment outcomes.

Cellular contribution to left and right atrial dysfunction in chronic arterial hypertension in pigs

Aims

Atrial contractile dysfunction contributes to worse prognosis in hypertensive heart disease (HHD), but the role of cardiomyocyte dysfunction in atrial remodelling in HHD is not well understood. We investigated and compared cellular mechanisms of left (LA) and right atrial (RA) contractile dysfunction in pigs with HHD.

Methods and results

In vivo electrophysiological and magnetic resonance imaging studies were performed in control and pigs treated with 11‐deoxycorticosterone acetate (DOCA)/high‐salt/glucose diet (12 weeks) to induce HHD. HHD leads to significant atrial remodelling and loss of contractile function in LA and a similar trend in RA (magnetic resonance imaging). Atrial remodelling was associated with a higher inducibility of atrial fibrillation but unrelated to changes in atrial refractory period or fibrosis (histology). Reduced atrial function in DOCA pigs was related to reduced contraction amplitude of isolated LA (already at baseline) and RA myocytes (at higher frequencies) due to reduced intracellular Ca release (Fura 2‐AM, field stimulation). However, Ca regulation differed in LA and RA cardiomyocytes: LA cardiomyocytes showed reduced sarcoplasmic reticulum (SR) [Ca], whereas in RA, SR [Ca] was unchanged and SR Ca²⁺‐ATPase activity was increased. Sodium–calcium exchanger (NCX) activity was not significantly altered. We used ORM‐10103 (3 μM), a specific NCX inhibitor to improve Ca availability in LA and RA cardiomyocytes from DOCA pigs. Partial inhibition of NCX increased Ca²⁺ transient amplitude and SR Ca in LA, but not RA cells.

Conclusions

In this large animal model of HHD, atrial remodelling in sinus rhythm in vivo was related to differential LA and RA cardiomyocyte dysfunction and Ca signalling. Selective acute inhibition of NCX improved Ca release in diseased LA cardiomyocytes, suggesting a potential therapeutic approach to improve atrial inotropy in HHD.

CaMKIIδC Drives Early Adaptive Ca2+ Change and Late Eccentric Cardiac Hypertrophy

Supplemental Digital Content is available in the text.

CaMKII (Ca²⁺-Calmodulin dependent protein kinase) δC activation is implicated in pathological progression of heart failure (HF) and CaMKIIδC transgenic mice rapidly develop HF and arrhythmias. However, little is known about early spatio-temporal Ca²⁺ handling and CaMKII activation in hypertrophy and HF.

Enhanced inter-compartmental Ca2+ flux modulates mitochondrial metabolism and apoptotic threshold during aging

Background

Senescence is characterized by a gradual decline in cellular functions, including changes in energy homeostasis and decreased proliferation activity. As cellular power plants, contributors to signal transduction, sources of reactive oxygen species (ROS) and executors of programmed cell death, mitochondria are in a unique position to affect aging-associated processes of cellular decline. Notably, metabolic activation of mitochondria is tightly linked to Ca²⁺ due to the Ca²⁺ -dependency of several enzymes in the Krebs cycle, however, overload of mitochondria with Ca²⁺ triggers cell death pathways. Consequently, a machinery of proteins tightly controls mitochondrial Ca²⁺ homeostasis as well as the exchange of Ca²⁺ between the different cellular compartments, including Ca²⁺ flux between mitochondria and the endoplasmic reticulum (ER).

Methods

In this study, we investigated age-related changes in mitochondrial Ca²⁺ homeostasis, mitochondrial-ER linkage and the activity of the main ROS production site, the mitochondrial respiration chain, in an in vitro aging model based on porcine aortic endothelial cells (PAECs), using high-resolution live cell imaging, proteomics and various molecular biological methods.

Results

We describe that in aged endothelial cells, increased ER-mitochondrial Ca²⁺ crosstalk occurs due to enhanced ER-mitochondrial tethering. The close functional inter-organelle linkage increases mitochondrial Ca²⁺ uptake and thereby the activity of the mitochondrial respiration, but also makes senescent cells more vulnerable to mitochondrial Ca²⁺-overload-induced cell death. Moreover, we identified the senolytic properties of the polyphenol resveratrol, triggering cell death via mitochondrial Ca²⁺ overload exclusively in senescent cells.

Conclusion

By unveiling aging-related changes in the inter-organelle tethering and Ca²⁺ communications we have advanced the understanding of endothelial aging and highlighted a potential basis to develop drugs specifically targeting senescent cells.

Early remodeling of perinuclear Ca2+ stores and nucleoplasmic Ca2+ signaling during the development of hypertrophy and heart failure

BACKGROUND

A hallmark of heart failure is impaired cytoplasmic Ca(2+) handling of cardiomyocytes. It remains unknown whether specific alterations in nuclear Ca(2+) handling via altered excitation-transcription coupling contribute to the development and progression of heart failure.

METHODS AND RESULTS

Using tissue and isolated cardiomyocytes from nonfailing and failing human hearts, as well as mouse and rabbit models of hypertrophy and heart failure, we provide compelling evidence for structural and functional changes of the nuclear envelope and nuclear Ca(2+) handling in cardiomyocytes as remodeling progresses. Increased nuclear size and less frequent intrusions of the nuclear envelope into the nuclear lumen indicated altered nuclear structure that could have functional consequences. In the (peri)nuclear compartment, there was also reduced expression of Ca(2+) pumps and ryanodine receptors, increased expression of inositol-1,4,5-trisphosphate receptors, and differential orientation among these Ca(2+) transporters. These changes were associated with altered nucleoplasmic Ca(2+) handling in cardiomyocytes from hypertrophied and failing hearts, reflected as increased diastolic Ca(2+) levels with diminished and prolonged nuclear Ca(2+) transients and slowed intranuclear Ca(2+) diffusion. Altered nucleoplasmic Ca(2+) levels were translated to higher activation of nuclear Ca(2+)/calmodulin-dependent protein kinase II and nuclear export of histone deacetylases. Importantly, the nuclear Ca(2+) alterations occurred early during hypertrophy and preceded the cytoplasmic Ca(2+) changes that are typical of heart failure.

CONCLUSIONS

During cardiac remodeling, early changes of cardiomyocyte nuclei cause altered nuclear Ca(2+) signaling implicated in hypertrophic gene program activation. Normalization of nuclear Ca(2+) regulation may therefore be a novel therapeutic approach to prevent adverse cardiac remodeling.

Abstract P4-04-13: Could genes associated with response or resistance to radiotherapy be identified in breast cancer patients?

Background. An absolute 10-year reduction of locoregional/distant relapse and 15-year reduction of mortality from breast cancer (BC) after breast conserving surgery by radiotherapy (RT) are about 16% and 3.8%, respectively (EBCTCG, Lancet 2011;378:1707–16). Similarly, after radical mastectomy absolute 5-year reduction of local recurrence by RT is 17% and 15-year BC mortality was reduced by 5.4% (EBCTCG, Lancet 2005,366:2087–2106). Predictive factors of response to RT are less frequently investigated compared to predictive factors for systemic therapy. The ideal model for researching the predictive value of markers is a neo-adjuvant setting. We have analyzed genes associated with different response to RT using neo-adjuvant model in locally-advanced (LA) BC patients (pts).

Patients and methods. This retrospective analysis included LA non-inflammatory BC pts treated with preoperative (P)RT alone with a total dose of 45 Gy in 15 fractions every second day to the breast and regional lymph nodes. Radical mastectomy was performed 6 weeks after PRT to all pts and adjuvant systemic therapy was administered as per protocol. Response to PRT was classified as pathological complete response (pCR) if there is no evidence of tumor in the breast after mastectomy, partial response (PR) if regression of tumor was >30%, and no response if regression was <30%. We have analyzed global gene expression profiles by microarray analysis in a set of 14 samples of formalin-fixed paraffin-embedded (FFPE) invasive breast cancer tissues.

Results. We have identified a group of 134 LABC pts treated with PRT between 1997 and 2000, which was the routine practice at that time according to the protocol for diagnosis and treatment of BC. Fourteen FFPE tumor samples, 7 from responders to PRT and 7 from non-responders to PRT, were collected for gene expression profile analysis. Unsupervised clustering analysis (Pearson correlation, un-centered metrics) over top 20% most variable genes, revealed clear separation of non-responders and responders. Unsupervised clustering analysis of paired pre- and post-PRT samples indicating small differences in expression profile in response to PRT within non-responders that were clustering together, unlike responders that were separated in the unsupervised analysis showing grater differences in their gene expression. We have found 98 genes significantly differentially expressed [Fals Discovery Rate (FDR) < 0.05] between responders and non-responders to PRT. Molecular functions significantly associated with this gene list were determined using Ingenuity Pathway Analysis and included regulation of cellular growth and proliferation, cell cycle, cell death and survival as top scoring function. Interestingly, canonical pathways for G2/M DNA damage checkpoint regulation and GADD45 genotoxic stress signaling were significantly enriched (FDR<0.05) among differentially expressed gene list between RT resistant and RT sensitive tumors.

Conclusion: The strength of these results is that, although obtained on a small number of pts, these tumours have been exposed only to RT without systemic therapy administered either previously or concomitantly with PRT. Further confirmatory research of potentially RT sensitive/resistant genes is warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-04-13.

Is there a correlation between molecular markers and response to neoadjuvant chemoradiotherapy in locally advanced squamous cell esophageal cancer?

PURPOSE

To evaluate the expression of epidermal growth factor receptor (EGFR), p53, p21 and thymidylate synthase (TS) in a pretherapy biopsy specimen of locally advanced squamous cell esophageal cancer and correlate these markers with response to neoadjuvant chemoradiotherapy.

METHODS

Sixty-two patients with histopathologically proven locally advanced (T3 or greater) squamous cell esophageal cancer were enrolled. The expression of EGRF, p53, p21 and TS markers was assessed with immunohistochemistry. Semiquantitative assessment of expression of these markers was performed based on the percent of the stained cells. Radiotherapy (45-50.4 Gy) was delivered concomitantly with 5-fluorouracil (5-FU)/leucovorin (LV)/cisplatin (CIS) chemotherapy. Five to 6 weeks after chemoradiation, response to treatment was assessed. Medically fit and operable patients were operated. The resected material underwent histopathological evaluation of tumor expansion, histological classification after initial multimodality treatment (yp TNM), residual status and tumor regression grade (TRG).

RESULTS

Out of 62 patients enrolled, 41 (66%) were evaluated for molecular markers. Clinical response rate was 43.9%. Out of 41 patients, 12 (29%) underwent surgery. TRG 1 was noted in 58% of the patients. In a pretherapy tumor specimen, positive expression was noted in 80, 90, 80 and 71% for EGFR, p53, p21 and TS, respectively. We noted no statistically significant difference neither between tumor marker expression and clinical response to chemoradiation, nor between tumor marker expression and TRG.

CONCLUSION

We registered no difference in response to treatment between EGFR, TS, p21 and p53 positive and negative staining.

TP53 gene status and human papilloma virus infection in response to platinum plus taxane-based chemotherapy of epithelial ovarian carcinomas

PURPOSE

Lack of symptoms in early stages of disease and resistance to chemotherapy make epithelial ovarian carcinomas one of the most lethal neoplasms among gynaecological malignancies. The aim of this study was to analyse the impact of TP53 mutations, codon 72 polymorphism and human papillomavirus (HPV) infection on the response to platinum-taxane combination chemotherapy in patients with epithelial ovarian carcinomas.

METHODS

The study was conducted on 26 ovarian carcinoma patients who received carboplatin plus paclitaxel combination chemotherapy. DNA was isolated by salting-out procedure. Mutations in exons 4-8 of TP53 gene were detected by PCR-SSCP and confirmed by automatic DNA sequencing. Codon 72 polymorphism was assessed by the RFLP method. HPV infection was detected through amplification of one part of L1 viral gene. Genotyping was performed by DNA sequencing. Fisher's exact and log-rank tests were used for statistical analysis.

RESULTS

TP53 mutations were present in 5/26 (19.2%) ovarian carcinomas. The distribution of codon 72 TP53 genotypes was: Arg/Arg 38.5%, Arg/Pro 50.0%, Pro/Pro 11.5%. HPV was present in 4/26 (15.4%) ovarian carcinomas. All HPV-positive tumors were HPV16 type. Patients with mutations in TP53 gene, Arg/Arg genotype of codon 72 and absence of HPV infection experienced the highest tumor response rate to platinum-taxane chemotherapy. However, no significant correlation between progression free interval (PFI) and the examined biomarkers was observed.

CONCLUSION

Our results indicate that, based on the TP53 gene status and the presence/absence of HPV infection, the subgroups of patients having better initial response to platinum-taxane therapy could be distinguished. This might contribute to more adequate treatment and individual therapeutic approach.

Expression of ERCC1 protein in biopsy specimen predicts survival in advanced ovarian cancer patients treated with platinum-based chemotherapy

PURPOSE

The purpose of this study was to investigate whether the expression of excision repair cross complementing 1 (ERCC1) protein I in tumor tissue was associated with resistance to standard carboplatin and paclitaxel (PC) combination chemotherapy in patients newly diagnosed with advanced epithelial ovarian carcinoma (EOC).

METHODS

Fresh frozen tumor tissue was obtained from EOC patients. The protein expression levels of ERCC1 in tumor tissue were determined by Western blot analysis in 55 samples with advanced and metastatic EOC with different histologic subtypes; then these patients were treated with PC.

RESULTS

The results showed that the clinical objective responses were significantly different in different categories of ERCC1 protein expression levels in patients with EOC. Time to progression (TTP) and overall survival (OS) in EOC patients previously treated with platinum-based chemotherapy were significantly longer in those with low expression compared with patients showing high expression of ERCC1 protein.

CONCLUSION

Our results revealed that ERCC1 protein expression could potentially be used to customize chemotherapy by defining subsets of patients who would benefit the least from platinum-based chemotherapy.

Systematic reviews of sublingual immunotherapy (SLIT)

Allergic rhinitis is common worldwide, with significant morbidity and impact on quality of life. In patients who don't respond adequately to anti-allergic drugs. Subcutaneous allergen immunotherapy is effective although requires specialist administration. Sublingual immunotherapy may represent an effective and safer alternative. This Cochrane systematic review is an update of one published in 2003. We searched Cochrane ENT Group Trials Register, Central, PubMed, EMBASE, CINAHL, Web of Science, Biosis Previews, Cambridge Scientific Abstarcts, mRCT and additional sources. We included randomised, double-blind, placebo- controlled trials of sublingual immunotherapy in adults and children. Two authors selected studies and assessed them for quality. Data were put into RevMan 5.0 for a statistical analysis. We used standardised mean difference (SMD), with a random effect model to combine data. Sixty studies were included, with 49 suitable for meta-analysis. We found significant reductions in symptoms (SMD -0.49; 95%CI (-0.64 to -0.34, P < 0.00001)) and medication requirements (SMD -0.32; 95%CI (-0.43 to -0.21, P < 0.00001)) compared with placebo. None of the trials reported severe systemic reactions, anaphylaxis or use of Adrenaline. This updated review reinforces the conclusion of the original 2003 Cochrane Review that sublingual immunotherapy is effective for allergic rhinitis and appears a safe route of administration.

Filaggrin loss-of-function mutations are associated with early-onset eczema, eczema severity and transepidermal water loss at 3 months of age

BACKGROUND

Filaggrin loss-of-function (FLG) mutations are associated with eczema and skin barrier impairment, but it is unclear whether skin barrier impairment precedes phenotypic eczema in FLG mutation carriers.

OBJECTIVES

To study the association between FLG mutations, skin barrier impairment and clinical eczema at 3 months of age.

METHODS

A total of 88 infants were examined for eczema. Disease severity was determined by the SCORAD eczema severity score. Transepidermal water loss (TEWL) was measured on unaffected forearm skin. Venous blood samples were screened for the four most common FLG mutations found in the U.K. white population (R501X, 2282del4, R2447X and S3247X). Median SCORAD and TEWL measurements in children with and without eczema and FLG mutations were compared.

RESULTS

Thirty-three per cent (29/88) of children had clinical eczema. Median SCORAD was 10·6 (range 3·5-31·0). TEWL (g m⁻² h⁻¹) was higher in children with eczema compared with unaffected infants (median TEWL 14·24 vs. 11·24, P < 0·001). Higher TEWL was associated with more severe disease (r = 0·59, P < 0·001, median TEWL, SCORAD < 15, 13·1 vs. 29·6, SCORAD ≥ 15, P = 0·029). Clinically dry skin was associated with higher TEWL, even in the absence of eczema (median TEWL 17·55 vs. 11·08, P = 0·008). Seventeen per cent (15/88) of children carried at least one FLG mutation. FLG mutation carriers were significantly more likely to have clinically dry skin, even in the absence of eczema [odds ratio (OR) 8·50, 95% confidence interval (CI) 1·09-66·58, P = 0·042]. FLG mutation carriers were also more likely to have eczema by 3 months of age (OR 4·26, 95% CI 1·34-13·57, P = 0·014). FLG mutations were significantly associated with higher median TEWL (all children, FLG 'yes' 21·59 vs. FLG 'no' 11·24, P < 0·001), even without clinical eczema (FLG 'yes' 15·99 vs. FLG 'no' 10·82, P = 0·01).

CONCLUSIONS

By the age of 3 months, FLG mutations are associated with an eczema phenotype, dry skin and TEWL. The observation that TEWL is elevated in unaffected FLG mutation carriers suggests that skin barrier impairment precedes clinical eczema.

p53 gene mutations and codon 72 polymorphism in ovarian carcinoma patients from Serbia

PURPOSE

Ovarian cancer is the leading cause of death from gynecological malignancies. The early stages of this disease are asymptomatic and more than 75% of the cases are diagnosed with regional or distant metastases. p53 gene is frequently mutated in some histological subtypes of ovarian carcinomas. The role of p53 mutations and polymorphic variant of codon 72 in the prognosis of disease is still unclear. The aim of this study was to determine the frequency of p53 mutations and polymorphic variants of codon 72 among ovarian carcinoma patients and to correlate them with clinicopathological characteristics of disease.

METHODS

54 ovarian carcinoma patients were included in the study. DNA was isolated from tumor tissue by the salting- out method. p53 mutations in exons 4-8 were detected by PCR-SSCP (polymerase chain reaction - single-stranded conformational polymorphism) electrophoresis. Codon 72 polymorphism was assessed by RFLP (restriction fragment-length polymorphism) method.

RESULTS

p53 mutations were present in 11 out of 54 patients (20.4%). Twenty-four patients (44.4%) exhibited Arg/ Arg, 24 patients (44.4%) Arg/Pro and 6 patients (11.2%) Pro/ Pro genotype of 72 codon polymorphism. Correlations between p53 mutations and various clinicopathological characteristics were not found. However, we observed that the frequency of Pro/Pro genotype was increasing with higher histological grade as well as in advanced compared to localized disease, but without statistical significance. Distribution of p53 gene mutations between Pro/Pro genotype and Arg/Pro plus Arg/Arg genotypes was not statistically significant.

CONCLUSION

Our study suggests that Pro/Pro genotype of 72 codon polymorphism could be an independent prognostic marker in ovarian carcinomas.

Therapeutic cancer vaccines in cervical cancer: phase I study of Lovaxin-C

Producing effective therapeutic vaccines has proved much more difficult and challenging than developing cancer preventive vaccines. Despite huge research in the area of cancer immunology, FDA/EMEA have not approved any type of cancer treatment vaccine so far. More than 99% of cervical cancers have detectable amounts of human papillomavirus (HPV) DNA. Integration of high-risk HPV into the host cell genome is followed by continual expression of HPV E6 and E7 oncoproteins, making them excellent targets for developing vaccines which could be used in high grade precancerous (CIN) lesions or invasive cancer or in the prevention of cancer recurrence. Therapeutic cervical cancer vaccines have been extensively studied. Strategies used were vaccination with HPV peptides or proteins, alone or in pulsed dendritic cells, DNA vaccines, virus-like particles or viral and bacterial vectors. Lovaxin-C is a recombinant live-attenuated Listeria monocytogenes (Lm) that secretes the antigen HPV-16 E7 fused to a non-hemolytic listeriolysin O protein. In a phase I study Lovaxin-C was administered to advanced cervical cancer patients refractory to existing therapies. The dose-limiting toxicity was hypotension and flue-like syndrome. There were no serious adverse events. Specific T-cell response was detected as well as clinical response to Lovaxin-C. Several other therapeutic HPV vaccines are in clinical development and in most of the studies specific immunological and clinical responses were seen. Efficacious therapeutic vaccine for the treatment of cervical cancer should be expected in the near future.

siRNA and miRNA for the treatment of cancer

In the process of RNA interference (RNAi), small RNAs pair with complementary messenger RNAs preventing their expression. The discovery of RNAi has revolutionized our understanding of gene regulation. Since cancer is a disease of altered genes, RNAi may have tremendous potential as a therapeutic strategy by downregulating altered genes. Just one decade after its discovery, this process is already being used in clinical trials and new technical achievements in delivering small RNAs to the cells are constantly improving the efficiency of this specific cancer treatment.

p53 gene alterations and human papillomavirus type 16 infection in early stages of cervical carcinoma in Serbia

PURPOSE

The incidence rate (age-standardized) of cervical carcinoma in Serbia is the highest in Europe. p53 is mainly inactivated at protein level in carcinomas associated with human papillomavirus (HPV) infection, such as cervical carcinomas. These tumors show low rate of p53 mutations. It is not clear if p53 mutations confer additional impact on disease prognosis. The role of polymorphic variant at codon 72 of p53 gene on patient's prognosis is controversial. The aim of this study was to determine the frequency of p53 mutations and to assess polymorphic variants of codon 72 among cervical carcinoma patients.

PATIENTS AND METHODS

53 patients, mainly FIGO stage I (n=50), with squamous cell carcinoma (n=49) were included. 30/32 (94%) patients who received adjuvant radiotherapy were followed-up (median 15 months, range 4-39). DNA was isolated by the salting out method from tumor tissue (n=53) and blood (42/53). p53 mutations were detected by PCR-SSCP (polymerase chain reaction - single-stranded conformational polymorphism) electrophoresis. Codon 72 polymorphism was assessed by the restriction fragment-length polymorphism method.

RESULTS

Six p53 mutations were detected in 5/53 (9%) patients with FIGO stage I squamous cell carcinoma (one patient had double mutations). 25/42 (60%) patients exhibited Arg/Arg genotype. HPV16 type was detected in 29/51 (57%) cervical carcinoma samples. Relapse of disease occurred in only 2 patients- both with Arg/Arg genotype and HPV16 positive. One of them exhibited p53 mutation.

CONCLUSION

Our results showed low incidence of p53 mutations and prevalence of Arg/Arg genotype polymorphic variant of codon 72 of p53 gene in early stages of cervical carcinoma.

Monitoring of NK cell activity and serum LDH in metastatic melanoma patients treated with DTIC and interferon-alpha2a, with or without retinoic acid

19000

Background: The activity of NK cells, expression of CD69, and serum LDH were evaluated in terms of response to therapy in metastatic melanoma patients. Methods: In phase II clinical study metastatic melanoma (MM) patients were treated with DTIC (800 mg/m2, d1) and IFN-alpha 2a (5×106 IU/m2 s.c., d2–6 (group A, n=25) and 28 patients received the same therapy supplemented with RA, 60 mg/d, d1–10 (group B). Before and after each therapy cycle NK cell activity, CD69+NKcells and LDH were monitored in patients and 39 healthy controls. Results: There is no significant difference in OR (group A 32%, B 21%), in time to progression between groups. NK cell activity was significantly decreased pretherapy in both groups, with a significant increase in the 1st cycle in both groups. NK cell activity did not show significant correlation with OS in group A compared to group B (p=0.445). 20% of patients in group A with pretherapy NK cell cytotoxicity above 30% had better survival from month 3 to 12 of follow-up and a longer maximal survival (1.2 vs. 1.0 year, respectively). In comparison to pre-therapy values, all responding MM patients had a significantly higher increase of CD69 expression on CD56+ NK cells, while the increase was only significantly higher in responders in group B. Analyses of serum LDH level show a significantly higher time and therapy cycle-dependent decrease in group A compared to group B (50% vs. 25%, respectively). However, it is shown that responders in group B had a significantly greater decrease in serum LDH level compared to responders in group B (70% vs. 20%, respectively), if the level after a cycle was evaluated in terms of pretherapy values, as well as a greater decrease if the evaluation in each cycle was done compared to each pretherapy value (35% vs. 20%, respectively). Conclusions: Even though there is no significance in clinical response between patients in group A and B, in agreement with a steady-state pattern of NK cell activity, the fact that only responders in group B had a significant increase in CD69 expression on CD56+ NK cells, as well as the finding that the decrease in serum LDH was significantly greater in patients in group B, implicates favorable imunopotentiating and antitumor effect of RA in the therapy of metastatic melanoma.

No significant financial relationships to disclose.

Dose-finding study of capecitabine in combination with weekly paclitaxel for patients with anthracycline-pretreated metastatic breast cancer

PURPOSE

Capecitabine and paclitaxel show high efficacy, non-overlapping toxicity profiles and preclinical synergism, providing the rationale for their combination in metastatic breast cancer (MBC). This dose-escalation study aimed at determining the maximum tolerated dose (MTD) of capecitabine plus paclitaxel in anthracycline-pretreated MBC patients.

PATIENTS AND METHODS

Patients with MBC received fl at-dose of oral capecitabine (1,000 mg/m(2) twice daily, days 1-14) plus weekly paclitaxel 60, 75, or 90 mg/m(2), i.v., days 1, 8 and 15, every 3 weeks.

RESULTS

All 11 patients enrolled onto study were evaluable for toxicity and response. Two patients receiving paclitaxel 75 mg/m(2) experienced grade 3 nail toxicity, with grade 3 hand-foot syndrome (HFS) in one patient and grade 2 dermatitis in the other. Although not life-threatening, these were considered unacceptable and the preceding dose level was selected. Eight of 11 patients achieved objective responses.

CONCLUSION

The recommended regimen is capecitabine 1,000 mg/m(2) twice daily, days 1-14, plus paclitaxel 60 mg/m(2)/week. Escalation of the paclitaxel dose above 60 mg/m(2)/week is not feasible due to severe skin toxicity.

Chemosensitisation by poly(ADP-ribose) polymerase-1 (PARP-1) inhitor 5-aminoisoquinoline (5-AIQ) on various melanoma cell lines

12019

Background: PARP-1 facilitates DNA strand brakes repair and PARP inhibitors were investigated as enhancers of chemoradiotherapy. We investigated whether 5-AIQ potentates the effect of doxorubicin (DOXO), cisplatin (CDDP) and paclitaxel (Ptx) on human (slow-growing) FemX and murine (fast-growing) B16 melanoma cell lines. Methods: Twenty-four hours after cells were seeded in 96 well plates, cytotoxic drugs and 5-AIQ were added to cell medium. For evaluation of single-agent activity, drugs were applied in concentration ranges as follows: CDDP (0.3–30 μM), DOXO (0.1–3 μM), Ptx (1–100 ηM), 5-AIQ (1–100 μM). 5-AIQ (3μM) was combined with CDDP (0.1, 0.3, 1 μM), DOXO (10, 3, 100 ηM), or Ptx (1, 3, 10 ηM). Incubation lasted for 72 hrs when SRB assay was utilized to determine individual and combine activity (interactions calculated with isobole method). For cell cycle analysis B16 cells were seeded on 6 well plates and treated with each drug alone and combinations, using the same concentrations as those for investigation of combine cytotoxic activity. Cell cycle was determined after 72 hrs, on FACS Calibur with propidium iodide dye. Results: 5-AIQ induced minimal changes in cell viability and cell cycle progression on both cell lines, compared to non-treated control. CDDP revealed high activity against FemX (IC50 = 2.85 μM) and B16 cells (IC50 = 8.84 μM), and G0/G1 arrest. In B16 cells 5-AIQ multiply enhanced CDDP’s activity with strong synergistic interaction and cells slightly driven to S phase. Synergism was also detected on B16 cells treated with combination of DOXO (IC50 = 0.2 μM on B16 and 0.89 μM on FemX) and 5-AIQ when DOXO was applied in low concentrations (10 and 30 ηM), while 5-AIQ did not interfere with cell cycle changes. Cytotoxicity of Ptx (IC50 = 6.16 ηM on B16 and <1 ηM on FemX) was stimulated only at higher concentrations. 5-AIQ stimulated G0/G1 and S phase arrest on B16 cells with Ptx of 3 and 10 ηM, respectively. In FemX cells, most of the interactions of 5-AIQ with CDDP, DOXO, and Ptx revealed as antagonistic. Conclusions: PARP-1 inhibitor 5-AIQ enhances cytotoxic activity of both DNA damaging and agents with different mechanism of action, but the effect varies between cell lines with different proliferation rate.

No significant financial relationships to disclose.

Cellular Sensitivity to β-Diketonato Complexes of Ruthenium(III), Chromium(III) and Rhodium(III)

The aim of this study was to investigate cellular response to several ruthenium(III), chromium(III) and rhodium(III) compounds carrying bidentate beta-diketonato ligands: [(acac)--acetylacetonate ligand, (tfac)--trifluoroacetylacetonate ligand]. Cell sensitivity studies were performed on several cell lines (A2780, cisplatin-sensitive and -resistant U2-OS and U2-OS/Pt, HeLa, B16) using growth-inhibition assay. Effect of intracellular GSH depletion on cell sensitivity to the agents was analyzed in A2780 cells. Flow cytometry was used to assess apoptosis by Annexin-V-FITC/PI staining, and to analyze induction of caspase-3 activity. Possible DNA binding/damaging affinity was investigated, by inductively coupled mass spectrometry, and by 14C-thymidine / 3H-uridine incorporation assay. Cell sensitivity studies showed that the pattern of sensitivity to Ru(tfac)3 complex of the two cisplatin-sensitive/-resistant osteosarcoma cell lines, U2-OS and U2-OS/Pt, was similar to that of A2780 cells (72 h exposure), with the IC50 being around 40 microM. The growth-inhibitory effect of Ru(acac)3 ranged over 100 microM, while Cr(III) and Rh(III) complexes were completely devoid of antitumor action in vitro. Ru(tfac)3 exhibited strong potential for apoptosis induction on A2780 cells (up to 40%) and caused cell cycle arrest in the S phase as well as decrease of the percent of G1 and G2 cells. Ru(acac)3-induced apoptosis was slightly higher than 10%, whereas activation of caspase-3 in HeLa cells was moderate. DNA binding study revealed that only Cr(acac)3 was capable of binding DNA, while Cr(III) and Ru(III) compounds possess potential to inhibit DNA/RNA synthesis. In conclusion, only Ru(III) complexes showed potential for antitumor action.

Antiproliferative activity of some cis-/trans-platinum(II) complexes on HeLa cells

Purpose of this work was to synthesize several cis-/trans- isomer pairs of the platinum(II) complexes, and study the extent and the mode of their antiproliferative activity on HeLa cells. Six platinum(II) isomer pairs have a general formula cis-/trans-[PtA2X2], where A is ligand: ammonia (NH3), pyridine (Py); and X is ligand: chloride ion (Cl-), bromide ion (Br-), iodide ion (I-), thiocyanato ion (SCN-); four compounds have different structural formulas, and these are cis-/trans-[Pt(NH2OH)2(NH3)2]Cl2, and cis-/trans-Pt(Gly)2, where Gly is bidentate glycinato ligand. Results of the MTT assay, showed that six cis- and one trans-platinum(II) complexes exhibited cytotoxicity (IC50) ranging between 5 and 33 microM. Most of the cis-platinum(II) isomers caused significant alteration of cell cycle phases progression, and induced apoptosis in degree that varied among different compounds, as evaluated using flowcytometry and morphological study. Spectrophotometric analysis (AAS) indicated that there is no correlation between intracellular platinum(II) accumulation and cytotoxicity of tested complexes.

Trans-platinum complexes as anticancer drugs: recent developments and future prospects

Cisplatin represents one of the most potent drugs available in the cancer chemotherapy for several solid tumors, such as germ cell tumors, ovarian, lung, head and neck, and bladder cancers. Structure-activity relationship studies showed that leaving groups (generally chlorine) and two amine ligands in platinum complexes must be in the cis orientation and that the corresponding trans compounds are inactive. During the 1990's, several groups have reported trans-platinum compounds with in vitro growth inhibitory and in vivo antitumor properties. Some of these complexes were active against tumor cells resistant to cisplatin. More interestingly, there is a difference in cellular and biochemical pharmacology between trans-platinum complexes and cisplatin. Thus, monofunctional adducts might be related to the cytotoxicity of the trans-platinum-iminoether compounds against cis-DDP sensitive/resistant cell lines; unusual structure of long-range interstrand cross-links might be relevant for great effectivity of bifunctional polinuclear trans-platinum(II) compounds against cis-DDP resistant variants. Trans-platinum compounds, appear to follow different pattern of cell killing in comparison to cisplatin, thus giving a reason for optimism in their development as a new class of platinum-based antitumor drugs.

Rickettsia-macrophage interactions: host cell responses to Rickettsia akari and Rickettsia typhi

The existence of intracellular rickettsiae requires entry, survival, and replication in the eukaryotic host cells and exit to initiate new infection. While endothelial cells are the preferred target cells for most pathogenic rickettsiae, infection of monocytes/macrophages may also contribute to the establishment of rickettsial infection and resulting pathogenesis. We initiated studies to characterize macrophage-Rickettsia akari and -Rickettsia typhi interactions and to determine how rickettsiae survive within phagocytic cells. Flow cytometry, microscopic analysis, and LDH release demonstrated that R. akari and R. typhi caused negligible cytotoxicity in mouse peritoneal macrophages as well as in macrophage-like cell line, P388D1. Host cells responded to rickettsial infection with increased secretion of proinflammatory cytokines such as interleukin-1beta (IL-1beta) and IL-6. Furthermore, macrophage infection with R. akari and R. typhi resulted in differential synthesis and expression of IL-beta and IL-6, which may correlate with the existence of biological differences among these two closely related bacteria. In contrast, levels of gamma interferon (IFN-gamma), IL-10, and IL-12 in supernatants of infected P388D1 cells and mouse peritoneal macrophages did not change significantly during the course of infection and remained below the enzyme-linked immunosorbent assay cytokine detection limits. In addition, differential expression of cytokines was observed between R. akari- and R. typhi-infected macrophages, which may correlate with the biological differences among these closely related bacteria.

Inhibition of human epithelial ovarian cancer cell growth in vitro by somatostatin analog RC-160

In this study, we investigated the effects of somatostatin analog RC-160 on the growth of the OV-1063 human epithelial ovarian cancer cell line in vitro. RC-160 inhibited cell proliferation, as measured by cell number, and [(3)H]thymidine incorporation into DNA at 10(-9)-10(-5) M. In OV-1063 cells, (125)I-labeled RC-160 was bound to one class of specific, saturable binding sites with high affinity (K(d) = 0.2 +/- 0.03 nM) and low capacity (5,500 binding sites per cell). (125)I-labeled RC-160 could be displaced by unlabeled RC-160. Ligand binding was dependent on time and temperature. Receptor internalization assay showed that the ligand-receptor complex was internalized at 37 degrees C, which indicates the presence of biologically active somatostatin receptors on OV-1063 cells. These results suggest that somatostatin analog RC-160 can suppress the growth of OV-1063 human epithelial ovarian cancer cells by a direct action and that the inhibitory effect of somatostatin analog is mediated through the high-affinity somatostatin receptors.