Report from the OECI Oncology Days 2014

The 2014 OECI Oncology Days was held at the 'Prof. Dr. Ion Chiricuta' Oncology Institute in Cluj, Romania, from 12 to 13 June. The focus of this year's gathering was on developments in personalised medicine and other treatment advances which have made the cost of cancer care too high for many regions throughout Europe.

A stress-induced early innate response causes multidrug tolerance in melanoma

Acquired drug resistance constitutes a major challenge for effective cancer therapies with melanoma being no exception. The dynamics leading to permanent resistance are poorly understood but are important to design better treatments. Here we show that drug exposure, hypoxia or nutrient starvation leads to an early innate cell response in melanoma cells resulting in multidrug resistance, termed induced drug-tolerant cells (IDTCs). Transition into the IDTC state seems to be an inherent stress reaction for survival toward unfavorable environmental conditions or drug exposure. The response comprises chromatin remodeling, activation of signaling cascades and markers implicated in cancer stemness with higher angiogenic potential and tumorigenicity. These changes are characterized by a common increase in CD271 expression concomitantly with loss of differentiation markers such as melan-A and tyrosinase, enhanced aldehyde dehydrogenase (ALDH) activity and upregulation of histone demethylases. Accordingly, IDTCs show a loss of H3K4me3, H3K27me3 and gain of H3K9me3 suggesting activation and repression of differential genes. Drug holidays at the IDTC state allow for reversion into parental cells re-sensitizing them to the drug they were primarily exposed to. However, upon continuous drug exposure IDTCs eventually transform into permanent and irreversible drug-resistant cells. Knockdown of CD271 or KDM5B decreases transition into the IDTC state substantially but does not prevent it. Targeting IDTCs would be crucial for sustainable disease management and prevention of acquired drug resistance.

Skeletal muscle damage and impaired regeneration due to LPL-mediated lipotoxicity

According to the concept of lipotoxicity, ectopic accumulation of lipids in non-adipose tissue induces pathological changes. The most prominent effects are seen in fatty liver disease, lipid cardiomyopathy, non-insulin-dependent diabetes mellitus, insulin resistance and skeletal muscle myopathy. We used the MCK(m)-hLPL mouse distinguished by skeletal and cardiac muscle-specific human lipoprotein lipase (hLPL) overexpression to investigate effects of lipid overload in skeletal muscle. We were intrigued to find that ectopic lipid accumulation induced proteasomal activity, apoptosis and skeletal muscle damage. In line with these findings we observed reduced Musculus gastrocnemius and Musculus quadriceps mass in transgenic animals, accompanied by severely impaired physical endurance. We suggest that muscle loss was aggravated by impaired muscle regeneration as evidenced by reduced cross-sectional area of regenerating myofibers after cardiotoxin-induced injury in MCK(m)-hLPL mice. Similarly, an almost complete loss of myogenic potential was observed in C2C12 murine myoblasts upon overexpression of LPL. Our findings directly link lipid overload to muscle damage, impaired regeneration and loss of performance. These findings support the concept of lipotoxicity and are a further step to explain pathological effects seen in muscle of obese patients, patients with the metabolic syndrome and patients with cancer-associated cachexia.

Overexpression of the anti-apoptotic protein AVEN contributes to increased malignancy in hematopoietic neoplasms

AVEN has been identified as an inhibitor of apoptosis, which binds to the adaptor protein, APAF-1, and thereby prevents apoptosome formation and mitochondrial apoptosis. Recent data have demonstrated high expression levels of AVEN messenger RNA in acute leukemias as well as a positive correlation between AVEN mRNA overexpression and poor prognosis in childhood acute lymphoblastic leukemia. On the basis of these data, we investigated the potential involvement of AVEN in tumorigenesis. First, we confirmed the overexpression of AVEN in T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) patient samples. We then established a transgenic mouse model with T-cell-specific overexpression of AVEN, with which we demonstrated the oncogenic cooperation of AVEN with heterozygous loss of p53. Finally, we used a subcutaneous xenograft mouse model to show that AVEN knockdown in the T-ALL cell lines, MOLT-4 and CCRF-CEM, and in the acute myeloblastic leukemia cell line, Kasumi-1, leads to a halt in tumor growth owing to the increased apoptosis and decreased proliferation of tumor cells. Collectively, our data demonstrate that the anti-apoptotic molecule, AVEN, functions as an oncoprotein in hematopoietic neoplasms.

Down-regulation of KRAS-interacting miRNA-143 predicts poor prognosis but not response to EGFR-targeted agents in colorectal cancer

BACKGROUND

MicroRNA-143 (miRNA-143) is frequently down-regulated in colorectal cancer (CRC) and may influence CRC cell proliferation, apoptosis and sensitivity to 5-fluorouracil. mRNA encoded by the KRAS oncogene has been identified as a target of miRNA-143. However, the prognostic significance of miRNA-143 expression and the ability to predict patient response to epidermal growth factor receptor (EGFR)-targeted agents have not yet been explored.

METHODS

We examined 77 CRC patients who were identified by pyrosequencing to have wild-type KRAS and were subsequently treated with EGFR-targeted therapy with the monoclonal antibodies cetuximab or panitumumab. MicroRNA-143 expression was measured in CRC tissue and corresponding non-neoplastic colon tissue by RT-PCR and its expression level was correlated with clinico-pathological characteristics. Univariate and multivariate analyses were used to calculate cancer-specific survival (CSS). The progression-free survival (PFS) and objective response rates on EGFR-targeted therapy were also evaluated.

RESULTS

Down-regulation of miRNA-143 was observed in 47 out of 77 (61%) tumours. Multivariate Cox regression analysis identified low levels of miRNA-143 expression as an independent prognostic factor with respect to CSS (hazard ratio=1.92, confidence interval=1.1-3.4, P=0.024). A significant difference was also observed with regard to PFS on EGFR-targeted therapy (P=0.031), but there were no significant differences with regard to the objective response rates.

CONCLUSION

Our data indicate that miRNA-143 expression levels serve as an independent prognostic biomarker for CRC in KRAS wild-type patients. No role for miRNA-143 expression as a predictive biomarker for EGFR-targeted agents could be identified. Given its negative impact on CSS and PFS, miRNA-143 represents a novel prognosticator and a promising drug target for patients with CRC.

Loss of RAF kinase inhibitor protein is a somatic event in the pathogenesis of therapy-related acute myeloid leukemias with C-RAF germline mutations

We recently described oncogenic and anti-apoptotic C-RAF germline mutations in patients with therapy-related acute myeloid leukemia (t-AML). Activation of the RAF effector ERK was restricted to transformed cells, suggesting the requirement for cooperating events in leukemogenesis. Western blot analysis of blast cells from patients with C-RAF germline mutations revealed loss of the tumor and metastasis suppressor RAF kinase inhibitor protein (RKIP). Immunohistochemistry of the patients' primary tumors revealed normal RKIP expression levels, indicating that the loss of RKIP is a somatic, t-AML-specific event. In focus formation assays, the oncogenic potential of human mutant C-RAF was strongly influenced by expression levels of RKIP. Although the number of colonies formed by C-RAF(S427G) was significantly increased by RKIP silencing, the opposite was observed after RKIP overexpression. These results show that the loss of RKIP is a functional somatic event in carriers of C-RAF germline mutations, which contributes to the development of t-AML.

KRAS mutation testing for predicting response to anti-EGFR therapy for colorectal carcinoma: proposal for an European quality assurance program

Novel therapeutic agents targeting the epidermal growth factor receptor (EGFR) have improved outcomes for patients with colorectal carcinoma. However, these therapies are effective only in a subset of patients. Activating mutations in the KRAS gene are found in 30-40% of colorectal tumors and are associated with poor response to anti-EGFR therapies. Thus, KRAS mutation status can predict which patient may or may not benefit from anti-EGFR therapy. Although many diagnostic tools have been developed for KRAS mutation analysis, validated methods and standardized testing procedures are lacking. This poses a challenge for the optimal use of anti-EGFR therapies in the management of colorectal carcinoma. Here we review the molecular basis of EGFR-targeted therapies and the resistance to treatment conferred by KRAS mutations. We also present guideline recommendations and a proposal for a European quality assurance program to help ensure accuracy and proficiency in KRAS mutation testing across the European Union.

mRNA expression patterns indicate CD30 mediated activation of different apoptosis pathways in anaplastic large cell lymphoma but not in Hodgkin's lymphoma

One of the main functions of the tumor necrosis factor receptor (TNFR) family is induction of apoptosis. CD30, a member of the TNFR superfamily is overexpressed in highly proliferating tumors such as anaplastic large cell lymphoma (ALCL) and Hodgkin's lymphoma (HL). CD30 stimulation leads to apoptosis and growth arrest in cultured ALCL, but not in Hodgkin-Reed-Sternberg cells. To identify changes in the transcriptional program responsible for these opposing effects, we performed gene expression analysis in CD30-stimulated ALCL (Karpas 299) and HL (KM-H2) cell lines using cDNA microarrays. Selected genes were validated by real-time PCR. Hierarchical clustering was applied to the whole dataset and separated the cell lines clearly with respect to their origin. In HL, there were only minor CD30-specific alterations, whereas ALCL unequivocally showed a pronounced CD30-specific transcriptional response. Ninety-three genes (6.6% of total) were deregulated by more than a factor of two after CD30 stimulation in ALCL cells. The majority of genes identified are involved in cell cycle regulation and apoptosis. mRNA expression patterns further indicate that in contrast to HL, CD30 stimulation in ALCL induces cell death via the CD95-CD95 ligand (CD95L) pathway and the TNF-R1/TNF-R2 crosstalk. These data provide a detailed view on the transcriptional changes upon CD30 stimulation and may explain the observed functional differences of HL and ALCL.

Critical issues in the identification and management of patients with hereditary non-polyposis colorectal cancer

Inherited defects of the DNA mismatch repair system are the underlying cause of the hereditary non-polyposis colorectal cancer (HNPCC) syndrome and are responsible for 3-4% of all cases of colorectal cancer. The HNPCC syndrome also carries the risk of development of additional malignancies such as endometrial, stomach, small bowel, ovarian, pancreas, ureter, renal pelvis, biliary tract and brain tumours. Amsterdam I and II criteria have been developed to clinically identify affected families. The revised Bethesda criteria function to select patients whose tumours should be investigated for microsatellite instability, the molecular hallmark of defects of the DNA mismatch repair proteins such as hMLH1 and hMSH2. Microsatellite instability-positive cases should be investigated for germline defects in the respective genes. This facilitates identification of affected family members that have to be included in special surveillance programmes, while unaffected family members are spared the physical discomfort and psychological burden of cancer surveillance. In this article, strategies for effective clinical as well as genetic detection of affected individuals, surveillance and appropriate preventive measures are discussed. Open questions include the role of chemoprevention, preventive surgical procedures, new endoscopic procedures as well as non-invasive 'virtual colonoscopy' and the exact implications of some mutations of the DNA mismatch repair genes. Perhaps most importantly, efforts should be made to more efficiently transfer information about the HNPCC syndrome and the cancer risk associated with it from the specialists to primary health care providers and the general public.

Prognostic relevance of tumour-associated macrophages and von Willebrand factor-positive microvessels in colorectal cancer

Tumour-associated macrophages (TAM) are involved in tumour angiogenesis and anti-tumour immune response. In colorectal cancer (CRC), an association of high microvascular density (MVD) and unfavourable prognosis has been reported by some investigators. However, heterogeneous patient groups were studied. We, therefore, analysed the correlation between TAM and MVD and the prognostic relevance of MVD, TAM and T lymphocyte infiltration for long-term survival in a homogeneous group of 70 patients with moderately differentiated cancers of the International Union Against Cancer (UICC) stages II and III, who did not receive chemotherapy. MVD was evaluated using immunohistochemistry with antibodies against CD34 and von Willebrand factor (vWF). TAM and T lymphocytes were visualised with antibodies against CD68 and CD3, respectively. Statistical analysis did not reveal a significant correlation between TAM and T lymphocyte numbers and MVD. Multivariate analysis of immunohistochemical data from all CRC patients and the subgroup of patients with UICC stage-II CRC identified TAM- and vWF-positive microvessel numbers as prognostically relevant markers. Low numbers of TAM- and high numbers of vWF-positive microvessels were associated with an unfavourable prognosis. In conclusion, TAM- and vWF-positive microvessel numbers may serve as independent prognostic markers for patients with UICC stage-II and -III CRC and may help to identify patients with an unfavourable prognosis.

Mutation analyses in 17 patients with deficiency in acid beta-galactosidase: three novel point mutations and high correlation of mutation W273L with Morquio disease type B

An inherited deficiency in beta-galactosidase can result in GM1 gangliosidosis, with several phenotypes of generalized or chronic psychomotor deterioration, as well as in Morquio disease type B, a characteristic mucopolysaccharidosis free of neurological symptoms. We performed mutation analyses in 17 juvenile and adult patients from various European regions with a deficiency in beta-galactosidase and skeletal abnormalities. Fifteen of these had the Morquio B phenotype and have remained neurologically healthy until now while the two others exhibited psychomotor retardation of juvenile onset. A two-base substitution (851-852TG-->CT; W273L) was present in 14 of the 15 Morquio B cases. Even if one excludes alleles from patients with possible common descent, there was a much higher frequency (79%) among those with Morquio B phenotype for the W273L mutation than previously reported in the literature (37%). That the Morquio phenotype is also expressed in heterozygotes for W273L and alleles typically found in GM1 gangliosidosis makes it possible to predict the phenotype and reliably detect heterozygotes. A single French patient had a novel missense point mutation (Q408P) together with a known mutation (T500A) while the mentally retarded patients were both heterozygous for two mutations known in chronic GM1 gangliosidosis together with two novel missense point mutations (Y270D and H281Y) in the vicinity of W273L. Our results confirm the high impact of Trp 273 for the function of beta-galactosidase and the expression of the Morquio B phenotype. In addition, a second domain around the amino acids 400-500 may also be of significance.

Metabolic cardiomyopathies

The energy needed by cardiac muscle to maintain proper function is supplied by adenosine Ariphosphate primarily (ATP) production through breakdown of fatty acids. Metabolic cardiomyopathies can be caused by disturbances in metabolism, for example diabetes mellitus, hypertrophy and heart failure or alcoholic cardiomyopathy. Deficiency in enzymes of the mitochondrial beta-oxidation show a varying degree of cardiac manifestation. Aberrations of mitochondrial DNA lead to a wide variety of cardiac disorders, without any obvious correlation between genotype and phenotype. A completely different pathogenetic model comprises cardiac manifestation of systemic metabolic diseases caused by deficiencies of various enzymes in a variety of metabolic pathways. Examples of these disorders are glycogen storage diseases (e.g. glycogenosis type II and III), lysosomal storage diseases (e.g. Niemann-Pick disease, Gaucher disease, I-cell disease, various types of mucopolysaccharidoses, GM1 gangliosidosis, galactosialidosis, carbohydrate-deficient glycoprotein syndromes and Sandhoff's disease). There are some systemic diseases which can also affect the heart, for example triosephosphate isomerase deficiency, hereditary haemochromatosis, CD 36 defect or propionic acidaemia.

Complete remission of generalized relapsed extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type of the gastrointestinal tract after high-dose chemotherapy and autologous peripheral stem cell transplantation

Due to their homing properties, extranodal marginal zone B-cell lymphoma (MZBL) of mucosa-associated lymphoid tissue (MALT) type remain localized for long periods of time, and therefore have an excellent prognosis. However, if generalization and/or transformation into a diffuse large-cell lymphoma occurs, the prognosis deteriorates and no established treatment concepts are yet available. We report about a 57-year-old female patient with relapsed transformed stage-IV extranodal MZBL of MALT type of the entire gastrointestinal tract who was successfully treated using salvage chemotherapy followed by BEAM conditioning [BCNU 1,3-bis-2-(chloroethyl-1-nitrosourea), etoposide, cytosine arabinoside, and melphalan] and autologous peripheral stem cell transplantation. Follow-up revealed a sustained complete remission for 22 months.

Extramedullary T cell lymphoblastic transformation of chronic myeloid leukaemia successfully treated with matched unrelated donor bone marrow transplantation

Chronic myeloid leukaemia (CML) inevitably terminates in blast crisis (BC) which is of myeloid phenotype in approximately two-thirds and B-lymphoid in one-third of patients. T cell BC is rare and associated with poor prognosis. We describe the case of a 48-year-old woman with extramedullary T cell lymphoblastic transformation. After treatment with combination chemotherapy she achieved a second chronic phase and underwent an allogeneic BMT from an HLA-matched unrelated donor. At 30 months follow-up she is still in complete molecular remission and in good clinical condition. We conclude that unrelated donor BMT should be considered as a therapeutic option for patients with extramedullary BC.

Nasopharyngeal angiofibroma: an APC-gene-associated tumor?

Nasopharyngeal angiofibromas are extremely rare, locally invasive tumors of unknown cause exclusively occurring in male adolescents. Recently, 6 cases have been reported in patients with familial adenomatous polyposis coli (Gardners syndrome). Mutations or allelic loss of the adenomatous polyposis coli (APC) gene have therefore been implied in the pathogenesis of nasopharyngeal angiofibroma. The authors analyzed 11 cases of nasopharyngeal angiofibromas from 9 male patients for mutations in the mutation cluster region and allelic loss of the APC gene. Six were primary tumors; 2 first recurrences; and 1, primary tumor with 2 recurrences. Direct sequence analysis was performed on several overlapping polymerase chain reaction (PCR) products. Detection of allelic loss was performed by restriction length polymorphism analysis at a polymorphic locus. No mutation was detected in 11 tumors of 9 different patients. None of the 9 informative (heterozygous) cases carried an allelic loss. We conclude that alterations of the APC gene do not play a major role in the development of nasopharyngeal angiofibroma. The coincidence of nasopharyngeal angiofibromas and adenomatous polyposis coli in some families implies the possibility that another gene in this region might be responsible for the development of nasopharyngeal angiofibromas. HUM PATHOL 31:1411:1413.

cDNA cloning and analysis of tissue-specific expression of mouse peroxisomal straight-chain acyl-CoA oxidase

Straight-chain acyl-CoA oxidase is the first and rate limiting enzyme in the peroxisomal beta-oxidation pathway catalysing the desaturation of acyl-CoAs to 2-trans-enoyl-CoAs, thereby producing H2O2. To study peroxisomal beta-oxidation we cloned and characterized the cDNA of mouse peroxisomal acyl-CoA oxidase. It consists of 3778 bp, including a 1983-bp ORF encoding a polypeptide of 661 amino-acid residues. Like the rat and human homologue the C-terminus contains an SKL motif, an import signal present in several peroxisomal matrix proteins. Sequence analysis revealed high amino-acid homology with rat (96%) and human (87%) acyl-CoA oxidase in addition to minor homology ( approximately 40%) with other related proteins, such as rabbit trihydroxy-cholestanoyl-CoA oxidase, human branched chain acyl-CoA oxidase and rat trihydroxycoprostanoyl-CoA oxidase. Acyl-CoA oxidase mRNA and protein expression were most abundant in liver followed by kidney, brain and adipose tissue. During mouse brain development acyl-CoA oxidase mRNA expression was highest during the suckling period indicating that peroxisomal beta-oxidation is most critical during this developmental stage. Comparing tissue mRNA levels of peroxisome proliferator-activated receptor alpha and acyl-CoA oxidase, we noticed a constant relationship in all tissues investigated, except heart and adipose tissue in which much more, and respectively, much less, peroxisome proliferator-activated receptor alpha mRNA in proportion to acyl-CoA oxidase mRNA was found. Our data show that acyl-CoA oxidase is an evolutionary highly conserved enzyme with a distinct pattern of expression and indicate an important role in lipid metabolism.

Mutational analysis of the DNA mismatch repair gene hMLH1 in myeloid leukaemias

Mutations of the DNA mismatch repair (MMR) gene hMLH1 have recently been linked to the development of some hereditary and sporadic cancers which frequently display widespread microsatellite instability (MSI). Conflicting results regarding the extent of MSI in myeloid leukaemias prompted us to perform mutational analysis of all 19 exons of the hMLH1 gene by polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) and sequence analysis in a total of 133 patients with acute and chronic myeloid leukaemia. Apart from one exonic and one intronic polymorphism, no mutations were detected in any of the samples indicating that the major MMR gene hMLH1 is not involved in the pathogenesis or progression of myeloid malignancies.

Two case studies of chronic idiopathic neutropenia preceding acute myeloid leukaemia

Chronic idiopathic neutropenia is regarded as a benign disorder without risk of malignant transformation. We present two patients with chronic idiopathic neutropenia who showed disease progression to acute myeloid leukaemia. Sequence analysis of the granulocyte-colony stimulating factor receptor (G-CSFR) gene from leukaemic DNA did not reveal any mutations and microsatellite analysis provided no evidence of microsatellite instability or loss of constitutional heterozygosity. These case studies suggest that chronic idiopathic neutropenia may constitute a preleukaemic condition in some patients. Alterations of the G-CSFR or defective DNA mismatch repair do not appear to be involved in malignant transformation.

ABL amplification in a patient with lymphoid blast crisis of chronic myelogenous leukaemia

Although chronic phase myelogenous leukaemia (CML) is characterised by the Philadelphia (Ph) chromosome leading to a fusion of the BCR and ABL genes, additional genetic alterations involved in blast crisis are poorly understood. We report an at least 15-fold amplification of the ABL oncogene in a 29-year-old male patient with a variant Ph-positive t(19;22)(p13;q11.2) CML who presented in lymphoid blast crisis. Our finding suggests that an amplification of the ABL oncogene might play a part in the appearance of an aggressive phenotype in some cases of CML.

The role of UV-radiation in the development of conjunctival malignant melanoma

PURPOSE

To investigate the possible role of UV-radiation in the development of conjunctival malignant melanoma. N-ras mutations are frequently found in cutaneous melanomas of sun-exposed body areas. UV-radiation is thought to induce mutations in the N-ras gene, that convert these genes into active oncogenes. The presence of N-ras mutations has been considered an indicator for UV-exposure in the development of melanomas on sun-exposed body sides.

METHODS

We analyzed six paraffin-embedded conjunctival melanomas for mutations of the N-ras gene. Codons 12, 13 and 61 were amplified using polymerase chain reaction and sequenced.

RESULTS

We could not detect point mutations of the N-ras gene in our samples.

CONCLUSION

Since we could not find deviations from the wild type sequence in the N-ras gene, our study does not support UV-exposure as being causative in the development of conjunctival melanoma.

Peroxisomal bifunctional protein deficiency revisited: resolution of its true enzymatic and molecular basis

In the past few years, many patients have been described who have a defect of unknown origin in the peroxisomal beta-oxidation pathway. Complementation analysis has been done by various groups to establish the extent of the genetic heterogeneity among the patients. These studies were based on the use of two established cell lines, one with a deficiency of acyl-CoA oxidase and one with a deficiency of l-bifunctional protein (l-BP), and they showed that most patients belong to the l-BP-deficient group. However, molecular analysis of the cDNA encoding l-BP in patients failed to show any mutations. The recent identification of a new d-specific bifunctional protein (d-BP) prompted us to reinvestigate the original patient with presumed l-BP deficiency. In a collaborative effort, we have now found that the true defect in this patient is at the level of the d-BP and not at the level of the l-BP. Our results suggest that most, if not all, patients whose condition has been diagnosed as l-BP are, in fact, d-BP deficient. We tested this hypothesis in nine patients whose condition was diagnosed as l-BP deficiency on the basis of complementation analysis and found clear-cut mutations in the d-BP cDNA from all patients.

Expression of CD44 splice variant v10 in Hodgkin's disease is associated with aggressive behaviour and high risk of relapse

Expression of CD44 isoforms has been shown to correlate with the progression and prognosis of some malignant tumours. The aim of this study was to investigate the expression of CD44 standard (CD44s) and CD44 splice variants (CD44v) v5, v6, and v10 in lymph node specimens from patients with nodular sclerosing Hodgkin's disease (NSHD), with or without initial bone marrow involvement and with or without relapse. Specimens were studied by immunohistochemistry to determine CD44s and CD44v in Hodgkin- and Reed-Sternberg (HRS) cells. For validation of the immunohistochemical of detection of CD44v10 in paraffin-embedded samples, selected cases were analysed in parallel immunohistochemically using fresh frozen material and by reverse transcription-polymerase chain reaction (RT-PCR). There was high expression of CD44 isoforms containing the variant exon v10 selectively in HRS cells of patients with relapse within 2-3 years or with initial bone marrow involvement. In patients without relapse, however, no or only very few HRS cells were positive. These differences were statistically highly significant (p < or = 0.001), whereas evaluation of CD44s, CD44v5, and v6 expression revealed no marked differences. It is concluded that evaluation of CD44v10 expression could serve as a new prognostic marker in NSHD. These results are considered to be of sufficient importance to initiate a large multi-institutional study for confirmation; furthermore, they might suggest causal involvement of CD44v10 in the progression of NSHD.

Venous thrombosis in a replanted finger with underlying factor V Leiden mutation

Resistance to activated protein C (APC resistance) was described recently as a cause for thrombophilia. APC inactivates coagulation co-factors Va and VIIIa. A single base-pair mutation changing Arg506 to Gln at the APC cleavage site of the factor V gene leads to a factor V Leiden variant, which is the most frequent cause of APC resistance. Recently, its role in peripheral venous thrombosis during pregnancy was described. We here report a case with thrombosis of the venous anastomoses after finger replantation with resistance to activated protein C associated with factor V Leiden mutation.

Presence of mycobacterial DNA in sarcoidosis

In 11 of 35 clinically proven cases of sarcoidosis, we detected DNA sequences coding for the mycobacterial 65-kDa antigen. In four cases, the sequences were homologous to Mycobacterium avium; seven sequences were related to other nontuberculous Mycobacteria. The insertion sequence 1110, characteristic for Mycobacterium avium, was present in three cases. The insertion sequence 6110 of the Mycobacterium tuberculosis complex (M tuberculosis, africanum, bovis, BCG) was not detectable in any of the 11 cases, ruling out the presence of members of the Mycobacterium tuberculosis complex. Therefore, it seems reasonable to speculate about a mycobacterial cause in some cases of sarcoidosis.

Deletion analysis of the p16 tumor suppressor gene in gastrointestinal mucosa-associated lymphoid tissue lymphomas

BACKGROUND & AIMS

The molecular mechanisms responsible for initiation and progression of gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphomas are largely unknown. The aim of this study was to analyze the p16 tumor suppressor gene in MALT lymphomas of the stomach and colon.

METHODS

Tumor samples were obtained from 28 patients with low-grade (n = 12) and high-grade (n = 14) gastric MALT lymphomas and from 2 patients with colonic MALT lymphomas. DNA was extracted from microdissected areas with at least 80% tumor cells. To detect homozygous p16 deletions, a semiquantitative polymerase chain reaction assay was used, whereby either p16 exon 1 or exon 2 was coamplified with an unrelated sequence as internal control.

RESULTS

Homozygous p16 deletions were found in 2 of 14 (14%) cases with high-grade gastric MALT lymphomas. Both patients had Helicobacter pylori-associated gastritis; however, DNA extracted from areas of gastritis showed a normal p16 complement. No deletion was found in any of the low-grade gastric or the colonic MALT lymphoma specimens.

CONCLUSIONS

In a subset of gastric MALT lymphomas, homozygous p16 deletions are acquired and may contribute to the transformation from a low-grade to a high-grade malignancy.

Muscle-specific overexpression of human lipoprotein lipase in mice causes increased intracellular free fatty acids and induction of peroxisomal enzymes

A transgenic mouse model for peroxisomal and mitochondrial induction caused by increased uptake of fatty acids in muscle was established. Transgenic mouse lines were generated using a human lipoprotein lipase (LPL) mini gene (3-20 copies) driven by the promoter of the muscle creatine kinase gene. Expression of human LPL was only observed in skeletal and cardiac muscle. In proportion to the level of LPL overexpression increased LPL activity in skeletal (up to 24-fold) and cardiac (up to three-fold) muscle, decreased plasma triglyceride levels, elevated free fatty acid (FFA) uptake by muscle tissue, weight loss (due to a reduction in muscle mass as well as adipose tissue mass) and premature death were observed. A remarkable increase in the number of mitochondria and peroxisomes was detected using oxide-electron microscopy. Proliferation of mitochondria and peroxisomes was confirmed by a dose-dependent increase of marker enzyme activity (succinate-dehydrogenase and catalase). In addition, peroxisomal acyl-CoAse enzyme protein was markedly elevated whereas mRNA was increased only up to two-fold. No changes in peroxisomal proliferator activated receptor alpha mRNA was found. This degree of proliferation and enzyme activity of mitochondria and peroxisomes suggests that FFA play an important role in the induction of these organelles. In addition, myopathy characterized by excessive glycogen storage, muscle fiber degeneration, and fiber atrophy with centralization of nuclei, mimicking several forms of human myopathies was noted. Our results imply that improper regulation of muscle LPL leading to increased fatty acid levels in muscle can cause severe pathological changes. This effect may be important in the pathogenesis of human myopathies. We conclude that these transgenic mouse lines could serve as a useful animal model for the investigation of myopathies and the effects of fatty acids on the induction of mitochondria and peroxisomes.

Acute Budd-Chiari syndrome with fulminant hepatic failure in a pregnant woman with factor V Leiden mutation

Budd-Chiari syndrome during pregnancy has rarely been reported. This report presents a case of acute hepatic failure in a 20-year-old pregnant woman attributable to Budd-Chiari syndrome with underlying resistance to activated protein C caused by factor V Leiden mutation. The patient delivered a healthy girl by cesarean section in the 31st week of pregnancy. Acute hepatic failure in the 6th week postpartum was successfully treated by emergency liver transplantation, and the patient and her child were doing well at 8-month follow-up. Liver transplantation was lifesaving; normal factor V production by the transplant corrected the underlying coagulopathy. In this patient, latent thrombophilia attributable to activated protein C resistance was apparently aggravated by the hypercoagulable state of pregnancy leading to acute Budd-Chiari syndrome. Activated protein C resistance should be sought as an etiologic factor in patients with Budd-Chiari syndrome.

Gallium-67-citrate scintigraphy of high-grade T-cell non-Hodgkin's lymphoma

Scintigraphy with 67Ga-citrate indicated the transition of an orbital pseudotumor into a lymphoma by a distinct increase in 67Ga avidity. The patient initially presented with a pseudotumor in the right orbit that was verified by CT and MRI. It was caused by a chronic reactive lymphocytic inflammation extending from the lacrimal gland. At that time, scintigraphy was negative. Six and a half weeks later, the tumor had not responded to therapy and scintigraphy then showed a striking increase in gallium avidity. Consequently the tumor was excised and histology ultimately revealed a high-grade non-Hodgkin's T-cell lymphoma.

Cloning and tissue expression of two cDNAs encoding the peroxisomal 2-enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase in the guinea pig liver

The 2-enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (HD) is the second enzyme of the peroxisomal beta-oxidation pathway. In human and rat, only one HD mRNA has been so far detected in the liver. This paper reports for the first time in a mammal species, the guinea pig, the cloning and sequencing of two cDNAs encoding an HD. The 3,274 nucleotide-cDNA is a strictly identical but longer copy of the 2,494 nucleotide-form. A 2,178 bp-open reading frame encodes a protein of 726 amino acids (M(r) 79.3 kDa) with the peroxisomal-targeting signal (tripeptide SKL) at the carboxyterminus. Northern blot analysis of HD mRNA identified three mRNAs of respective sizes 3.5, 2.6 and 1.6 kb in the guinea pig liver and kidneys.

Muscle-specific overexpression of lipoprotein lipase causes a severe myopathy characterized by proliferation of mitochondria and peroxisomes in transgenic mice

In extrahepatic tissues lipoprotein lipase (LPL) hydrolyzes triglycerides thereby generating FFA for tissue uptake and metabolism. To study the effects of increased FFA uptake in muscle tissue, transgenic mouse lines were generated with a human LPL minigene driven by the promoter of the muscle creatine kinase gene. In these mice human LPL was expressed in skeletal muscle and cardiac muscle, but not in other tissues. In proportion to the level of LPL overexpression, decreased plasma triglyceride levels, elevated FFA uptake by muscle tissue, weight loss, and premature death were observed in three independent transgenic mouse lines. The animals developed a severe myopathy characterized by muscle fiber degeneration, fiber atrophy, glycogen storage, and extensive proliferation of mitochondria and peroxisomes. This degree of proliferation suggests that FFA play an important role in the biogenesis of these organelles. Our experiments indicate that LPL is rate limiting for the supply of muscle tissue with triglyceride-derived FFA. Improper regulation of muscle LPL can lead to major pathological changes and may be important in the pathogenesis of some human myopathies. Muscle-specific LPL transgenic mouse lines will serve as a useful animal model for the investigation of myopathies and the biogenesis of mitochondria and peroxisomes.

Recurrent Salmonella enteritidis sepsis and hepatic tuberculosis

A 33 year old woman with recurrent Salmonella enteritidis sepsis is described. Penicillins, ceftriaxone, ciprofloxacin, and chloramphenicol could not eradicate the salmonellas but a combination of high dose ciprofloxacin and ceftriaxone for the eighth episode successfully cured the infection. The combination of ciprofloxacin and ceftriaxone may be a valuable therapeutic regimen in patients with recurrent salmonella sepsis. Prolonged intrahepatic cholestasis resulting from granulomatous hepatitis in this patient improved considerably with empiric ursodeoxycholic acid treatment. A liver biopsy specimen showing non-caseating epitheloid granulomas was positive for mycobacterial DNA by polymerase chain reaction. Repeated bronchoscopy with multiple biopsies eventually revealed caseating granulomas with acid fast bacilli in the lung biopsy specimens. Therefore, tuberculosis was diagnosed as the underlying disease and the cause of granulomatous hepatitis in this patient and tuberculostatic treatment was started. Polymerase chain reaction for mycobacterial DNA may be helpful in the differential diagnosis of hepatic granulomas when routine histological examination and culture of biopsy specimens are not diagnostic. Tuberculosis should be considered as one of the diseases predisposing to recurrent salmonella sepsis.

Heavy-chain immunoglobulin gene rearrangement and cytoplasmic immunoglobulin expression in acute monocytic leukemia following primary germ cell tumor

A case of acute monocytic leukemia with rearrangement of the immunoglobulin heavy-chain gene and strong cytoplasmic immunoglobulin expression in a young patient treated with multi-drug chemotherapy for primary seminomatous germ cell tumor 13 months earlier is reported. The short latency period from the beginning of therapy for primary germ cell tumor and the abrupt onset of leukemia with no identifiable prodrome bear similarities to podophyllotoxin-related leukemias.

Cholesterol biosynthesis in dermal fibroblasts from patients with metabolic disorders of peroxisomal origin

As peroxisomes possess some of the integral enzymes for cholesterol biosynthesis, the role of these organelles in cholesterol formation was studied in dermal fibroblasts with three types of peroxisomal defect: group I, characterized by the absence of intact peroxisomes (neonatal adrenoleukodystrophy, cerebrohepatorenal syndrome of Zellweger); group II, showing impaired activity of a single peroxisomal enzyme (X-linked adrenoleukodystrophy, adrenomyeloneuropathy); and group III, defective in more than one peroxisomal enzyme (rhizomelic chondrodysplasia punctata). Cells were incubated with three different radioactive precursors, namely [14C]-octanoate, [14C]-acetate, and [3H]-mevalonate, and incorporation of these radiolabels into cholesterol was determined. All fibroblasts with peroxisomal defects were able to form cholesterol at concentrations comparable or higher than those in controls dependent on the radioactive substrate. Binding properties (KD) and bmax values) of LDL to fibroblasts with peroxisomal defects and downregulation of intracellular cholesterol biosynthesis were similar to those found in fibroblasts from normolipidaemic controls, but different to those observed in LDL-receptor negative fibroblasts. As our studies revealed that cholesterol biosynthesis is not impaired in fibroblasts from patients with metabolic disorders of peroxisomal origin, we conclude that peroxisomes play little or no role in the pathway of cholesterol synthesis beyond mevalonate. In earlier steps of the cholesterol synthesis pathway, peroxisomal and mitochondrial defects in parallel may alter cholesterol synthesis indirectly.

Expression of three- and four-repeat tau isoforms in mouse liver

Tau protein is a member of the family of microtubule-associated proteins, which support microtubule polymerization and stability. Under pathological conditions, tau is a major constituent of neurofibrillary tangles in nerve cells of patients with Alzheimer's disease. Neurofibrillary tangles share some morphological, biochemical and immunological properties with cytoplasmic inclusions associated with other diseases, such as Mallory bodies in the livers of patients with alcoholic hepatitis and in corresponding mouse models. Recently a Mallory body component was identified that in molecular mass and isoelectric point resembles the abnormally phosphorylated tau of neurofibrillary tangles. There has been, however, so far no report describing the occurrence of tau in normal liver. We now demonstrate the expression of two tau isoforms containing three and four repeats, respectively, of the microtubule-binding domains in normal mouse liver and kidney. This finding provides evidence for a physiological role of tau in the liver and, consequently, the basis for the involvement of tau in pathological situations.

Familial hemophagocytic lymphohistiocytosis associated with disseminated T-cell lymphoma: a report of two siblings

Two siblings with evidence of disseminated T-cell lymphoma at the time of diagnosis of familial hemophagocytic lymphohistiocytosis (FHL) are reported, an association which has not been described previously. The first child with typical clinical and laboratory features of FHL died shortly after admission, before diagnosis could be established. Retrospective analysis of autoptic tissue revealed marked hemophagocytosis as well as morphological and immunohistochemical features suggestive of disseminated T-cell lymphoma. In the second child, FHL was diagnosed in time. Subsequent histologic investigation of bone marrow biopsies displayed a focal infiltration by T-cell lymphoma. DNA hybridization studies provided evidence of a monoclonal T-cell receptor beta chain gene rearrangement. Following conventional chemotherapeutic induction for FHL, the patient received an allogeneic bone marrow transplant (BMT) from a related healthy donor. Currently, 17 months after BMT, the boy is in unmaintained remission from FHL and T-cell lymphoma. The current pathogenetic concepts for FHL and a possible relationship between T-cell lymphoma and FHL are discussed.

cDNA cloning of the human peroxisomal enoyl-CoA hydratase: 3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and localization to chromosome 3q26.3-3q28: a free left Alu Arm is inserted in the 3' noncoding region

Enoyl-CoA hydratase:3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme is one of the four enzymes of the peroxisomal beta-oxidation pathway. Here, we report the full-length human cDNA sequence and the localization of the corresponding gene on chromosome 3q26.3-3q28. The cDNA sequence spans 3779 nucleotides with an open reading frame of 2169 nucleotides. The tripeptide SKL at the carboxy terminus, known to serve as a peroxisomal targeting signal, is present. DNA sequence comparison of the coding region showed an 80% homology between human and rat bifunctional enzyme cDNA. The 3' noncoding sequence contains 117 nucleotides homologous to an Alu repeat. Based on sequence comparison, we propose that these nucleotides are a free left Alu arm with 86% homology to the Alu-J family. RNA analysis shows one band with highest intensity in liver and kidney. This cDNA will allow in-depth studies of molecular defects in patients with defective peroxisomal bifunctional enzyme. Moreover, it will also provide a means for studying the regulation of peroxisomal beta-oxidation in humans.

Cyclooxygenase pathway in dermal fibroblasts from patients with metabolic disorders of peroxisomal origin

Cyclooxygenase metabolism was studied in fibroblasts from patients with metabolic disorders of peroxisomal origin (adrenomyeloneuropathy, X-linked adrenoleukodystrophy, cerebrohepatorenal syndrome of Zellweger and rhizomelic chondrodysplasia punctata). In response to arachidonic acid (6.25-100 microM) or calcium ionophore A23187 (2.5-20 microM) prostaglandin E2 and 6-keto-prostaglandin F1 alpha are the main cyclooxygenase metabolites formed. No formation of thromboxane B2 or 2,3-dinor-thromboxane B2 was found. Apparently due to the heterogeneous nature of peroxisomal disorders no uniform pattern of cyclooxygenase metabolism and eicosanoid concentrations in cell lines from patients with peroxisomal defects was found.

Photosensitized killing of cultured fibroblasts from patients with peroxisomal disorders due to pyrene fatty acid-mediated ultraviolet damage

The influence of pyrene-fatty acids on the resistance of cells to ultraviolet (UV) radiation was investigated in cultured fibroblasts from patients with five types of peroxisomal disorders. All showed reduced survival compared to control. The effect varied with the biochemical defect involved and the chain length of the pyrene fatty acid. Reduced survival was observed in cells deficient in plasmalogens (rhizomelic chondrodysplasia punctata) and in cells deficient in peroxisomal fatty acid oxidation (bifunctional enzyme deficiency), which accumulated pyrene-fatty acids. X-linked adrenoleukodystrophy fibroblasts accumulated pyrene-fatty acids and showed increased UV sensitivity only when exposed to longer-chain pyrene fatty acids. UV radiation resistance was lowest in cells with combined impairment of plasmalogen synthesis and fatty acid oxidation (Zellweger syndrome, neonatal adrenoleukodystrophy), suggesting that UV sensitivity correlates inversely with the ratio of plasmalogens to radical producing substances. Fibroblasts deficient in plasmalogens gained normal UV resistance when their plasmalogen levels were normalized by hexadecylglycerol. UV resistance increased when Zellweger cells were fused with X-linked adrenoleukodystrophy cells, and also when Zellweger cells belonging to different complementation groups were fused. The results provide leads to the pathogenesis of the multiple malformations associated with peroxisomal disorders and a method for the selection of cells in which the metabolic defect has been corrected.

Peroxisomal fatty acid beta-oxidation in HepG2 cells

HepG2 cells, originally derived from a human hepatoblastoma, contain peroxisomes which could be separated from mitochondria and other subcellular organelles by density gradient centrifugation. To determine whether this cell line was a suitable model for human peroxisomal fatty acid beta-oxidation, we investigated the ability of these cells to catabolize very-long-chain fatty acids (VLCFA). HepG2 cell homogenates or digitonin-disrupted cells oxidized both long chain fatty acids and VLCFA, although at somewhat lower rates than human liver homogenates. beta-Oxidation of VLCFA was observed in both peroxisomes and mitochondria of HepG2 cells. Peroxisomal beta-oxidation was independent of carnitine, insensitive to antimycin A and rotenone, and not blocked by an inhibitor of carnitine palmitoyl transferase I. HepG2 peroxisomes contained immunoreactive acyl-CoA oxidase, the first enzyme unique to the peroxisomal beta-oxidation pathway. In addition, HepG2 peroxisomes contained VLCFA-CoA synthetase activity. These results suggest that HepG2 may be a useful model system for the study of human peroxisomal metabolic processes, including beta-oxidation of fatty acids.

Import of human bifunctional enzyme into peroxisomes of human hepatoma cells in vitro

A polypeptide containing the carboxyl-terminal fragment of human peroxisomal enoyl-CoA hydratase:3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme was synthesized in vitro from its cDNA clone. This expression polypeptide was transported into purified rat liver peroxisomes. When the expression polypeptide was incubated with postnuclear supernatant fractions of human hepatoma cells and analyzed by Nycodenz gradient SDS-PAGE and fluorography, it was imported specifically into peroxisomes as indicated by its resistance to proteinase K degradation. A deletion of the last nine amino acid residues at the carboxyl-terminus of this polypeptide prevents its peroxisomal import. A tripeptide sequence, SKL, located at the carboxyl-terminus of human bifunctional enzyme appears to be the targeting signal for the peroxisomal importation of bifunctional enzyme in human cells.