Intra-Arterial Liver Chemotherapy and Hormone Therapy in Malignant Insulinoma: Case Report and Review of the Literature

Background

Malignant insulinoma is a rare tumor. Metastatic disease confined to the liver can be treated with various locoregional treatments.

Case report

We report a case of a young woman who developed liver metastases twelve years following resection of a pancreatic insulinoma positive to anti-insulin antibodies. With five cycles of intra-arterial locoregional chemotherapy (fluorouracil and epirubicin) to the liver and monthly hormone therapy (octreotide) the patient obtained a clinical complete response. After twelve months she is still disease free.

Conclusion

Locoregional therapy for insulinoma metastatic to the liver might represent the treatment of choice; hepatic intra-arterial chemotherapy is an interesting therapeutic approach which deserves attention. The role of somatostatin analogs is limited to symptom control.

Weekly Vinorelbine and Docetaxel as Second-Line Chemotherapy for Pretreated Non-Small Cell Lung Cancer Patients: a Phase I-II Trial

Docetaxel was proven to be effective as second-line therapy for patients with advanced NSCLC after failure of platinum-based front-line chemotherapy. We designed this phase I/II study to define the Maximum Tolerated Dose of weekly docetaxel combined with weekly vinorelbine, and subsequently evaluate tolerability and activity of this schedule in NSCLC patients who were progressive after treatment with either cisplatin and gemcitabine or carboplatin and paclitaxel regimens. To be eligible for the study, patients were required to have a WHO performance status < or =2, failure after at least two cycles of first platinum-based chemotherapy, and no prior treatment with docetaxel and vinorelbine. A total of 27 patients were enrolled in this phase I/II study. A weekly docetaxel dose of 25 mg/m2 was recommended in combination with fixed vinorelbine dose of 20 mg/m2, and 24 patients were treated at this dose level. Severe neutropenia (62%) and febrile neutropenia (29%) were the most frequent toxicities, with 83% of patients requiring dose modification or delay. In the phase II study, 5 (21%) patients obtained a partial response, 8 (33%) patients had stable disease, whereas 10 (42%) patients progressed. After a median follow-up of 18.7 months, median survival was 8 months, with 30% surviving at 1 year. Regardless of the use of weekly docetaxel schedule, this regimen was highly myelosuppressive, and did not seem to improve response rate and survival compared to single-agent docetaxel. No further developments of this schedule are warranted.

Genomic profiling of carbohydrate metabolism in the ectomycorrhizal fungus Tuber melanosporum

• Primary carbohydrate metabolism plays a special role related to carbon/nitrogen exchange, as well as metabolic support of fruiting body development, in ectomycorrhizal macrofungi. In this study, we used information retrieved from the recently sequenced Tuber melanosporum genome, together with transcriptome analysis data and targeted validation experiments, to construct the first genome-wide catalogue of the proteins supporting carbohydrate metabolism in a plant-symbiotic ascomycete. • More than 100 genes coding for enzymes of the glycolysis, pentose phosphate, tricarboxylic acid, glyoxylate and methylcitrate pathways, glycogen, trehalose and mannitol metabolism and cell wall precursor were annotated. Transcriptional regulation of these pathways in different stages of the T. melanosporum lifecycle was investigated using whole-genome oligoarray expression data together with real-time reverse transcription-polymerase chain reaction analysis of selected genes. • The most significant results were the identification of methylcitrate cycle genes and of an acid invertase, the first enzyme of this kind to be described in a plant-symbiotic filamentous fungus. • A subset of transcripts coding for trehalose, glyoxylate and methylcitrate enzymes was up-regulated in fruiting bodies, whereas genes involved in mannitol and glycogen metabolism were preferentially expressed in mycelia and ectomycorrhizas, respectively. These data indicate a high degree of lifecycle stage specialization for particular branches of carbohydrate metabolism in T. melanosporum.

The combination of carboplatin and weekly paclitaxel: a safe and active regimen in advanced non small-cell lung cancer patients. A phase I-II study

The combination of carboplatin and paclitaxel given every three weeks is a tolerated and reasonably active regimen in advanced non-small cell lung cancer (NSCLC). This study was designed to evaluate the maximum tolerated dose (MTD) of a fixed dose of carboplatin with an area under the curve (AUC) of 6 and escalating doses of weekly paclitaxel with an initial dose of 50 mg/m2 with 10 mg/m2 increments at each level in untreated NSCLC patients (phase I study). The study continued with a phase II study. Thirty patients entered the phase I study. The MTD was: carboplatin AUC = 6 on days 1 and 28 plus paclitaxel 100 mg/m2 (1 hour) on days 1, 8,15, 28. The dose-limiting toxicity (DLT) was severe neutropenia and cardiological toxicity. Subsequently, 42 patients entered the phase II study with the same treatment schedule. The 2-drug combination was globally well tolerated. The overall response rate (RR) was 42% [CI 95%: 26.3-57.7], stable disease (SD) 29% and progression (PD) 29%. The median duration of response was 8.0 mos (range: 1.0-19.0). The median time to progression was 8.0 mos (range: 7.0-19.0) and the median survival was 14.0 months (range: 9.0-19.0). The association of carboplatin AUC = 6 and weekly paclitaxel 100 mg/m2 proved to be manageable, active and extremely safe even in elderly patients (one third of all patients in our cohort). The survival results were interesting: the median survival time was 14 months (9-19 months) and the 1- and 2-year survival was 59% and 16%, respectively.

Cloning, expression, and characterization of the hxk-1 Gene from the white truffle Tuber borchii vittad.: A first step toward understanding sugar metabolism

Recent biochemical investigations of Tuber borchii Vittad. mycelium have demonstrated the presence of three distinct forms of hexokinase (HK(M1), HK(M2), and HKM3). In the investigation described here, a gene coding for hexokinase (hxk-1) from T. borchii was isolated and characterized. The hxk-1 gene is characterized by an ORF of 1494 nucleotides and codes for a polypeptide of 497 aa. The gene was overexpressed in Escherichia coli, and the recombinant protein was kinetically characterized. The K(cat) value for fructose is in agreement with the data reported for the hexokinase of Yarrowia lipolytica, the Km for ATP is not dependent on the sugar used, and the enzyme is not inhibited by trehalose 6-phosphate or glucose 6-phosphate. The biochemical characteristics confirm that this enzyme is a hexokinase, as suggested by the Pileup results, and it corresponds to the HKM1 isoform. This work represents the first characterization of the key enzyme of the glycolytic pathway and the related gene in a Tuber species.

Possible involvement of Pseudomonas fluorescens and Bacillaceae in structural modifications of Tuber borchii fruit bodies

Previous studies on Tuber borchii fruit bodies in early maturation stages suggested a role of bacteria in sporocarp structural modifications. In order to verify this hypothesis, in the present study we investigated by means of microbial and ultrastructural approaches, the bacterial population of T. borchii sporocarps from intermediate maturation phases to advanced decomposition stages, paying particular attention to chitinolytic and cellulolytic bacteria and to their relationships with ascii and ascospores. We found that Pseudomonas fluorescens and spore-forming Bacillaceae, both able to degrade cellulose and chitin, are present inside the sporocarps in all maturation stages investigated. Moreover, rod-shaped bacteria seem able to erode ascus walls and colonize the interior of ascii containing mature spores. These results suggest a possible role of these bacteria in the process of ascus opening. Moreover, the presence of P. fluorescens and Bacillaceae on isolated mature spores after decontamination suggests an intimate association between these bacteria and the ascospores.

Effects of different carbohydrate sources on the growth of Tuber borchii Vittad. mycelium strains in pure culture

The influence of carbohydrate utilisation on the growth of three strains of Tuber borchii Vittad. mycelium (1BO, 17BO and 10RA) in culture was assessed using culture media containing glucose (control), mannose or mannitol. Mannose was the best substrate for growth of the strains and this was particularly evident for strain 17BO. Mannitol instead was metabolized only by 10RA and 1BO. In order to explain the different growth trends, analyses of enzyme levels, kinetic parameters, protein patterns and the morphology of the three strains were carried out. Our results show that these strains of T. borchii mycelium were affected by the substrates used in the media. The aim of the present work was to optimise the in vitro production of T. borchii mycelium for use in experiments which require the fungus in precise and reproducible conditions, such as mycorrhizal synthesis or protein and nucleic acid extractions.

Three different forms of hexokinase are identified during Tuber borchii mycelium growth

Truffles are ectomycorrhizal fungi which have a great dependence on carbohydrates supplied by their host plants. The catabolism of hexoses in the mycobiont is important for the production of energy, and the first enzyme in the hexose assimilation pathways is hexokinase. This study reports differences in the expression of this enzyme during the growth of Tuber borchii Vittad. mycelium (strain ATCC 96540). Three hexokinase activities (HKM1, HKM2 and HKM3) were isolated by anion-exchange chromatography and partially purified. HKM1 and HKM2 were present in the linear phase at 15-50 days of growth. Two remarkable differences were found in the sugar-phosphorylating activity and stability of HKM1 and HKM2. HKM2 did not phosphorylate the fructose and it was present in the chromatographic profile only when substrates such as glucose, glucosamine or mannose were added to the extraction buffer. On the contrary, HKM1 utilized also fructose and was detected under all the experimental conditions used. HKM3 was the only molecular form observed after 70 days, when the fungus growth had reached a plateau. To our knowledge these results represent the first evidence for the presence in T. borchii mycelium of three distinct enzymatic forms of hexokinase which are differently expressed during growth of the fungus.

Hexokinase inactivation induced by ascorbic acid/Fe(II) in rabbit erythrocytes is independent of glutathione-reductive processes and appears to be mediated by dehydroascorbic acid

Recent studies performed in our laboratory demonstrated that rabbit red blood cell hexokinase was remarkably inhibited by the cocktail ascorbic acid/Fe(II) (Stocchi et al., 1994, Arch. Biochem. Biophys. 311, 160-167) and that the formation of dehydroascorbic acid was a key event in this process (Fiorani et al., 1996, Arch. Biochem. Biophys, 334, 357-361). The present study was undertaken to determine the final hexokinase-inactivating species using cell-free extract as a model. Our results demonstrate superimposable kinetics of hexokinase decay promoted by either ascorbic acid/Fe(II) or dehydroascorbic acid in erythrocyte lysates in which the reduced glutathione (GSH) levels were variously manipulated. In particular, neither removal nor addition of this tripeptide was able to significantly alter the rate or extent of hexokinase inhibition. Thus, GSH-reductive processes are dispensable events in the process of hexokinase inhibition promoted by ascorbic acid/Fe(II) in red blood cells. As a consequence, dehydroascorbic acid appears to be the species which directly inhibits hexokinase. This inference is further supported by the observation that addition of dehydroascorbic acid to the purified enzyme leads to a remarkable inhibition in its activity.

Role of dehydroascorbate in rabbit erythrocyte hexokinase inactivation induced by ascorbic acid/Fe(II)

In this study we investigated the species involved in the process of hexokinase inactivation induced by ascorbic acid/Fe(II) in rabbit erythrocytes. Our results suggest a model in which divalent iron is first oxidized to the trivalent state and then triggers the oxidation of ascorbic acid. The H202 formed during this process accelerates the formation of dehydroascorbic acid, which appears to be necessary and sufficient to induce hexokinase inactivation. This model was validated by showing that: (a) H202-decomposing enzymes, unlike scavengers of the hydroxyl radicals, reduced the extent of hexokinase inactivation; (b) when H202 was used instead of ascorbate/Fe(II), it was unable, even at very high concentrations, to inhibit hexokinase activity; (c) replacing Fe(II) with either Fe(III) or H202 resulted in comparable levels of ascorbic acid-induced hexokinase inactivation; (d) expression of maximal hexokinase inhibiting activity was also triggered via enzyme-catalyzed oxidation of ascorbic acid or direct addition of dehydroascorbic acid; (e) the level of dehydroascorbic acid, which was actively generated in the external medium upon addition of ascorbic acid/Fe(II), increased as a function of time. Taken together, these results demonstrate that the process of hexokinase inactivation induced by ascorbic acid/Fe(II) is mediated by dehydroascorbate and that iron and H202 have the sole function of accelerating its formation.

Mitochondria-bound hexokinase from rabbit reticulocytes is resistant to the inactivation induced by Fe(II)/ascorbate

Exposure of rabbit reticulocytes to Fe(II)/ascorbate induced a pronounced decay in hexokinase activity. In reticulocytes, this enzyme is present in at least three different molecular forms, Ia, Ia* and Ib, sub-types of hexokinase type I, which show different intracellular distribution. Hexokinase Ia and Ib are soluble, whereas hexokinase Ia* is almost entirely bound to the mitochondria. Anion exchange chromatography of hexokinase from intact reticulocytes exposed to Fe(II)/ascorbate revealed a selective inactivation of forms Ia and Ib, whereas the form Ia* did not show any decay. Binding to the mitochondrial membrane seems to be responsible for the observed resistance of the form Ia* to the inactivation elicited by Fe(II)/ascorbate. Indeed, by using a cell-free system in which hexokinase Ia* was solubilized using Triton X-100, the decay in hexokinase activity induced by iron/ascorbate involved all three enzymatic forms.