Dalibor Valík

Release of cytokeratin-18 and -19 fragments (TPS and CYFRA 21-1) into the extracellular space during apoptosis.

Serum fragments of cytokeratins‐18 and ‐19 (measured as TPS and CYFRA 21‐1, respectively) have traditionally been considered as markers of tumor proliferation, although the evidence is scarce for a causative relationship between proliferation and levels of TPS and CYFRA 21‐1. We examined whether apoptosis might produce TPS and CYFRA 21‐1 fragments. MCF‐7 breast cancer cells were treated with mitomycin C or agonistic anti‐CD95 antibody, and levels of TPS and CYFRA 21‐1 in tissue culture supernatants were compared with the frequency of cells exhibiting the following markers of cell death: intracellular cytokeratin‐18 cleavage, surface staining with annexin‐V, propidium iodide uptake, DNA fragmentation. Twenty‐four hours after inducing apoptosis, levels of TPS and CYFRA 21‐1 were elevated ≥ 4‐fold in culture supernatants. Elevations in TPS and CYFRA 21‐1 coincided with apoptosis measured by the first three cell death markers but preceded DNA fragmentation. These mitomycin C‐ and CD95‐mediated elevations were completely inhibited by co‐incubation with the caspase inhibitors Z‐VAD.fmk and Z‐IETD.fmk, respectively. We conclude that TPS and CYFRA 21‐1 can be abundantly released into the extracellular space during the intermediate stage of epithelial cell apoptosis. J. Cell. Biochem. 85: 670–677, 2002.

Combined biodifferentiating and antiangiogenic oral metronomic therapy is feasible and effective in relapsed solid tumors in children: single-center pilot study.

To outline an outpatient-based treatment for children with relapsed solid tumors, who already have been extensively pretreated, we defined a 4-drug protocol named COMBAT (combined oral maintenance biodifferentiating and antiangiogenic therapy). Using this protocol, we performed a pilot study to determine its feasibility in children with relapsed and/or high-risk pediatric solid tumors. Patients and Methods: 22 children received the COMBAT protocol. Treatment consisted of daily celecoxib administration along with daily 13-cisretinoic acid (2 weeks on / 2 weeks off) and cycles of metronomic temozolomide (90 mg/m2 for 42 days) and low-dose etoposide (21 days). The treatment was scheduled for a period of 1 year. Results: 9 of the 14 patients assessable for response demonstrated evidence of treatment benefit manifested as prolonged disease stabilization or response. The protocol medication was well tolerated with very good compliance. Only minimal side effects where observed which responded to dose modification or local therapy. Conclusions: The COMBAT regimen is well tolerated by patients with intensive prior therapy including myeloablative regimens. Favorable responses observed in this cohort of patients support the further exploration of this and/or similar strategies in the treatment of pediatric solid tumors.

Surface-enhanced laser desorption/ionization time-of-flight proteomic profiling of breast carcinomas identifies clinicopathologically relevant groups of patients similar to previously defined clusters from cDNA expression

IntroductionMicroarray-based gene expression profiling represents a major breakthrough for understanding the molecular complexity of breast cancer. cDNA expression profiles cannot detect changes in activities that arise from post-translational modifications, however, and therefore do not provide a complete picture of all biologically important changes that occur in tumors. Additional opportunities to identify and/or validate molecular signatures of breast carcinomas are provided by proteomic approaches. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) offers high-throughput protein profiling, leading to extraction of protein array data, calling for effective and appropriate use of bioinformatics and statistical tools.MethodsWhole tissue lysates of 105 breast carcinomas were analyzed on IMAC 30 ProteinChip Arrays (Bio-Rad, Hercules, CA, USA) using the ProteinChip Reader Model PBS IIc (Bio-Rad) and Ciphergen ProteinChip software (Bio-Rad, Hercules, CA, USA). Cluster analysis of protein spectra was performed to identify protein patterns potentially related to established clinicopathological variables and/or tumor markers.ResultsUnsupervised hierarchical clustering of 130 peaks detected in spectra from breast cancer tissue lysates provided six clusters of peaks and five groups of patients differing significantly in tumor type, nuclear grade, presence of hormonal receptors, mucin 1 and cytokeratin 5/6 or cytokeratin 14. These tumor groups resembled closely luminal types A and B, basal and HER2-like carcinomas.ConclusionOur results show similar clustering of tumors to those provided by cDNA expression profiles of breast carcinomas. This fact testifies the validity of the SELDI-TOF MS proteomic approach in such a type of study. As SELDI-TOF MS provides different information from cDNA expression profiles, the results suggest the techniques potential to supplement and expand our knowledge of breast cancer, to identify novel biomarkers and to produce clinically useful classifications of breast carcinomas.

Metronomic Chemotherapy with the COMBAT Regimen in Advanced Pediatric Malignancies: A Multicenter Experience

Background: The outcome of children with refractory/relapsed malignancies remains poor and novel therapies are urgently required. One of the promising approaches is metronomic chemotherapy. We present the clinical results of 74 children with advanced solid tumors treated according to treatment recommendation with data registry in three European pediatric centers. Methods: COMBAT (Combined Oral Metronomic Biodifferentiating Antiangiogenic Treatment) included low-dose daily temozolomide, etoposide, celecoxib, vitamin D, fenofibrate and retinoic acid. From 2004 to 2010, 74 children were enrolled. Results: The 2-year overall survival (OS) was 43.1% (median 15.4, range 1.3–69.9 months). Of the 74 patients, 50 patients (68%) died and 24 are alive: 6 (8%) with progressive disease, 7 (9%) with stable disease/partial response and 11 (15%) in complete response. Median time to response was 6 months. Of 62 patients with initially measurable disease, 25 (40%) had radiological response or stable disease. Fourteen of 25 showing clinical benefit responded within the first 6 months. The treatment was well tolerated on an outpatient basis. Regarding non-hematological toxicity of grade ≥2, hepatotoxicity of grade 3 occurred in 8 children and grade 3 cheilitis in 16 children. Conclusion: COMBAT is a feasible and effective treatment option for patients with relapsing/refractory malignancies. The treatment is well tolerated with a low acute toxicity profile.

Identification of alphaB-crystallin, a biomarker of renal cell carcinoma by SELDI-TOF MS

Spectrometric-based surface-enhanced laser desorption/ionization ProteinChip (SELDI-TOF) facilitates rapid and easy analysis of protein mixtures and is often exploited to define potential diagnostic markers from sera. However, SELDI- TOF is a relatively insensitive technique and unable to detect circulating proteins at low levels even if they are differentially expressed in cancer patients. Therefore, we applied this technology to study tissues from renal cell carcinomas (RCC) in comparison to healthy controls. We found that different biomarkers are identified from tissues than those previously identified in serum, and that serum markers are often not produced by the tumors themselves at detectable levels, reflecting the nonspecific nature of many circulating biomarkers. We detected and characterized áB-crystallin as an overexpressed protein in RCC tissues and showed differential expression by immunohistochemistry. We conclude that SELDI-TOF is more useful for the identification of biomarkers that are synthesized by diseased tissues than for the identification of serum biomarkers and identifies a separate set of markers. We suggest that SELDI-TOF should be used to screen human cancer tissues to identify potential tissue-specific proteins and simpler and more sensitive techniques can then be applied to determine their validity as biomarkers in biological fluids.

Multicenter analysis of soluble Axl reveals diagnostic value for very early stage hepatocellular carcinoma.

If diagnosed at early stages, patients with hepatocellular carcinoma (HCC) can receive curative therapies, whereas therapeutic options at later stages are very limited. Here, we addressed the potential of soluble Axl (sAxl) as a biomarker of early HCC by analyzing levels of sAxl in 311 HCC and 237 control serum samples from centers in Europe and China. Serum concentrations of sAxl were significantly increased in HCC (18.575 ng/mL) as compared to healthy (13.388 ng/mL) or cirrhotic (12.169 ng/mL) controls. Receiver operating characteristic curve analysis of sAxl in very early stage HCC patients (BCLC 0) showed an area under the curve (AUC) of 0.848, with a sensitivity of 76.9% and a specificity of 69.2%. α‐Fetoprotein (AFP)‐negative HCC patients displayed an AUC of 0.803, with sensitivity and specificity of 73% and 70.8%. Combination of sAxl and AFP improved diagnostic accuracy to 0.936 in very early HCC patients and to 0.937 in all HCC. Differential diagnosis of very early HCC versus liver cirrhosis showed a combined performance for sAxl and AFP of 0.901 with a sensitivity of 88.5% and a specificity of 76.7%. Furthermore, sAxl levels failed to be elevated in primary ovarian, colorectal and breast carcinomas as well as in secondary hepatic malignancies derived from colon. In summary, sAxl outperforms AFP in detecting very early HCC as compared to healthy or cirrhotic controls and shows high diagnostic accuracy for AFP‐negative patients. sAxl is specific for HCC and suggested as a biomarker for routine clinical use.

Second complete remission of relapsed medulloblastoma induced by metronomic chemotherapy.

Prognosis for children with relapsed medulloblastoma remains poor. Metronomic chemotherapy may offer some benefit to patients treated initially with intensive regimens. However, dosing and duration of such palliative treatment have not been systematically studied. Here we describe a child with medulloblastoma relapsing after initial high‐dose chemotherapy and standard radiotherapy. The patient was then treated with metronomic chemotherapy and achieved second complete remission after 21 months of treatment. Three months off therapy he relapsed again and died from progressive disease. This case illustrates the potential benefit of metronomic chemotherapy but also shows the uncertainty of when to stop metronomic chemotherapy while balancing toxicity. Pediatr Blood Cancer 2010;54:616–617.

Severe Encephalopathy Induced by the First but Not the Second Course of High-Dose Methotrexate Mirrored by Plasma Homocysteine Elevations and Preceded by Extreme Differences in Pretreatment Plasma Folate

Plasma homocysteine has recently been associated with the occurrence of methotrexate-related neurotoxicity. We observed extreme elevations of homocysteine in a 9-year-old boy presenting with leukemia treated with the ALL-BFM 95 protocol. Coma occurred at about the 71st hour from the first methotrexate administration, and lasted for 30 h but MRI and CT studies showed no intracranial pathology. The second course of high-dose methotrexate was administered with no complications. Homocysteine areas under the curve (AUC) were calculated as the sum of areas of rectangles during the 6-hour intervals from T₀ to T72 hours (AUC0–72) and methotrexate AUCs were evaluated using MW/PHARM3.3 software. The AUC of homocysteine during the first, toxic course was 5.2 times higher than AUC during the second administration, whereas AUC of methotrexate also differed by a factor of 5. Plasma concentrations of folate prior to the first and the second courses, respectively, were 4.4 versus 45 µmol/l making this difference the most striking discriminator between the two courses. Mutation analysis showed that the patient was heterozygous for the C677T mutation in the MTHFR gene. We suggest that plasma homocysteine, pretreatment plasma folate and possibly the presence of MTHFR mutations may be biomarkers of methotrexate toxicity and possibly its antifolate effect targeted towards the tumor as well.

Surface-enhanced laser desorption ionization/time-of-flight (SELDI-TOF) mass spectrometry (MS) as a phenotypic method for rapid identification of antibiotic resistance.

Based on experiments with 10 defined strains of Escherichia coli, we present a new method for bacterial phenotyping using SELDI-TOF mass spectrometry. Changes in bacterial protein profiles in the context of the time of cultivation and the antibiotic environment were minimal. Proteom subprofiling may further distinguish between strains with specific susceptibility to antimicrobials. Mass spec-based methods may become common in the future of bacterial pathogen identification in clinical microbiology diagnostics.

LightCycler SeptiFast technology in patients with solid malignancies: clinical utility for rapid etiologic diagnosis of sepsis

We retrospectively evaluated 54 results of the SeptiFast test from patients with solid malignancy admitted to the ICU between June 2009 and August 2011. Specimens from suspected bloodstream infection were analyzed using LightCycler SeptiFast (Roche Molecular Diagnostics according to the manufacturers instruction and evaluated in comparison with blood culture results obtained from blood sampled no longer than 24 hours before or after sampling for SeptiFast. Blood culturing and identification were performed according to the routine diagnostic procedures. The total number of blood cultures analyzed was 85, and finding a microorganism by either of the two tests was evaluated as positive. Consistently, negative results from SeptiFast and blood culture were obtained in 21 (39%) cases.