Penny M. A. Brasher

Gelatinase-A (MMP-2), gelatinase-B (MMP-9) and membrane type matrix metalloproteinase-1 (MT1-MMP) are involved in different aspects of the pathophysiology of malignant gliomas.

SummaryMatrix metalloproteinases (MMPs) have been implicated as important factors in gliomas since they may both facilitate invasion into the surrounding brain and participate in neovascularization. We have tested the hypothesis that deregulated expression of gelatinase-A or B, or an activator of gelatinase-A, MT1-MMP, may contribute directly to human gliomas by quantifying the expression of these MMPs in 46 brain tumour specimens and seven control tissues. Quantitative RT-PCR and gelatin zymography showed that gelatinase-A in glioma specimens was higher than in normal tissue; these were significantly elevated in low grade gliomas and remained elevated in GBMs. Gelatinase-B transcript and activity levels were also higher than in normal brain and more strongly correlated with tumour grade. We did not see a close relationship between the levels of expression of MT1-MMP mRNA and amounts of activated gelatinase-A. In situ hybridization localized gelatinase-A and MT1-MMP transcripts to normal neuronal and glia, malignant glioma cells and blood vessels. In contrast, gelatinase-B showed a more restricted pattern of expression; it was strongly expressed in blood vessels at proliferating margins, as well as tumour cells in some cases. These data suggest that gelatinase-A, -B and MT1-MMP are important in the pathophysiology of human gliomas. The primary role of gelatinase-B may lie in remodelling associated with neovascularization, whereas gelatinase-A and MT1-MMP may be involved in both glial invasion and angiogenesis.

Prospective study of paclitaxel-induced peripheral neuropathy with quantitative sensory testing.

Background. Paclitaxel-induced peripheral neuropathy (PN) may be severeand dose-limiting at initial doses ≥ 275 mg/M2, but itsneurotoxicity at doses ≤ 250 mg/M2 has been incompletelycharacterized. The purposes of this study were to characterize and quantifypaclitaxel-induced PN and to determine the utility of quantitative sensorytesting (QST). Methods. We prospectively examined clinically and by QST 37women with metastatic breast cancer, treated with paclitaxel (200–250mg/m2) (average number of cycles = 7.3 over an average of 20.1weeks). QST included thermal threshold (TT) and vibration threshold (VT).Results. Paresthesias appeared in 31 (84%) patients after an averageof 1.7 cycles and an average cumulative dose of 371.5 mg/M2. Symptomsoccurred after the first or second dose in 26 (84%) patients and thenstabilized in 10 (32%), improved in 13 (42%) despite continuedtreatment, resolved completely in 6 (19%), and were progressive in 2(7%). Paclitaxel was discontinued in only 1 (3%) patientbecause of neurotoxicity and no patient required dose reduction because ofPN. Thirty-six (97%) developed signs of PN. The most sensitive QSTwas great toe VT but QST did not predict or identify subclinical PN in anypatient. Neurologic syndromes other than PN developed in 12 (32%)patients, and 7 were due to metastatic cancer. Conclusions. 1)Paclitaxel-induced PN is mostly sensory, and begins after the first orsecond dose. At these doses the neuropathy is mild, and rarelydose-limiting. 2) QST quantified the neuropathy but was less sensitive thanthe clinical examination. 3) Knowledge of the features of paclitaxels PNallows it to be differentiated from other neurologic syndromes which maysignal tumor progression.

A randomized, controlled trial of intravenous clodronate in patients with metastatic bone disease and pain.

To evaluate the effectiveness of intravenous clodronate in ameliorating refractory bone pain in patients with metastatic bone disease, 60 patients with established osseous metastases and persistent bone pain were randomized to receive either clodronate (600 mg or 1500 mg in 500 mL of normal saline) or 500 mL of saline as placebo. After 2 weeks, the patients were crossed over to receive the alternate treatment. After another 2 weeks, each patient and investigator made a blinded choice. Daily visual analogue scales (VAS) and analgesic diaries were recorded throughout the study period. Forty-six patients were evaluable (77%). A treatment x period interaction was identified in the VAS and daily morphine equivalent dose (DMED) scores. First period analysis of the VAS scores for general pain, pain at rest, and pain upon movement demonstrated an average reduction of 13, 14, and 24 mm, respectively, from baseline, but were not significantly different from changes following placebo. The average change in DMED was -6.4 (SE = 2.9) following clodronate and was +24.6 (SE = 14.9) following placebo (p = 0.03). In the blinded choice of which agent resulted in improvement in pain, 26 (57%) patients chose clodronate, 12 (26%) chose placebo, and eight (17%) had no preference (p = 0.0021). For the investigators who also made a blinded selection, clodronate was chosen in 30 (65%) patients, placebo in ten (22%) patients, and no difference was apparent in six (13%) (p < 0.0001). Intravenous clodronate appeared to have analgesic effect in patients with refractory bone pain due to metastatic bone disease. The optimal dose and duration of effect require further evaluation, particularly in patients with stable disease and persistent bone pain.

Efficacy and Safety Evaluation of Human Reovirus Type 3 in Immunocompetent Animals: Racine and Nonhuman Primates

Purpose: Human reovirus type 3 has been proposed to kill cancer cells with an activated Ras signaling pathway. The purpose of this study was to investigate the efficacy of reovirus in immunocompetent glioma animal models and safety/toxicity in immunocompetent animals, including nonhuman primates. Experimental Design: Racine glioma cells 9L and RG2 were implanted s.c. or intracranially in Fisher 344 rats with or without reovirus antibodies, followed by treatment of reovirus. To study whether reovirus kills contralateral tumors in the brain and to determine viral distribution, we established an in situ dual tumor model followed by reovirus intratumoral inoculation only into the ipsilateral tumor. To evaluate neurotoxicity/safety of reovirus, Cynomolgus monkeys and immunocompetent rats were given intracranially with reovirus, and pathological examination and/or behavioral studies were done. Viral shedding and clinical biochemistry were systematically studied in monkeys. Results: Intratumorally given reovirus significantly suppressed the growth of both s.c. and intracranially tumors and significantly prolonged survival. The presence of reovirus-neutralizing antibodies did not abort the reovirus’ antitumor effect. Reovirus inhibited glioma growth intracranially in the ipsilateral but not the contralateral tumors; viral load in ipsilateral tumors was 15 to 330-fold higher than the contralateral tumors. No encephalitis or behavioral abnormalities were found in monkeys and rats given reovirus intracranially. No treatment-related clinical biochemistry changes or diffuse histopathological abnormality were found in monkeys inoculated intracranially with Good Manufacturing Practice prepared reovirus. Microscopic changes were confined to the region of viral inoculation and were dose related, suggesting reovirus intracranially was well tolerated in nonhuman primates. Conclusions: These data show the efficacy and safety of reovirus when it is used in the treatment of gliomas in immunocompetent hosts. Inoculation of reovirus into the brain of nonhuman primates did not produce significant toxicities.

Is primary CNS lymphoma really becoming more common? A population-based study of incidence, clinicopathological features and outcomes in Alberta from 1975 to 1996

BACKGROUND The incidence of primary CNS lymphoma (PCNSL) is believed to be increasing in immunocompetent patients but this may not be universally true. The objective of this study was to determine in a population if the incidence of PCNSL is increasing, if the histologic subtypes are changing, and to describe the clinicopathologic and outcome characteristics of PCNSL. PATIENTS AND METHODS We identified all Alberta residents with a histologic diagnosis of PCNSL from 1 January 1975 to 31 December 1996 using the Alberta Cancer Registry. Annual age-standardized incidence rates (ASIR), clinicopathologic and outcome characteristics were determined. RESULTS There were 50 immunocompetent PCNSL patients; the median age was 64 and 30 were male. Their median survival was 10.15 months. Histology was available for review in 37 (74%) patients: 19 (51%) were diffuse large cell, 16 (43%) were immunoblastic and 2 (5%) were unclassifiable malignant lymphomas. The ASIR ranged from 0.178-1.631/10(6) and no change in ASIR was found (test for trend, P = 0.26) for gender or age. The ASIR of malignant gliomas did not change either but increased for all other non-Hodgkins lymphoma (94.95-138.7610(6); test for trend, P = 0.0001) The number of brain biopsies increased from 1979-1985 (test for trend, P < 0.0001) but remained stable from 1986-1996 (test for trend, P = 0.99). CONCLUSIONS Unlike several other populations, PCNSL is not becoming significantly more common in Alberta. If this difference is real (i.e., not due to differences in cancer registry coding practices etc.) comparisons between Albertans and other populations in whom the incidence is rising may provide clues regarding the etiology of PCNSL.

Reovirus as an experimental therapeutic for brain and leptomeningeal metastases from breast cancer.

Brain and leptomeningeal metastases are common in breast cancer patients and our current treatments are ineffective. Reovirus type 3 is a replication competent, naturally occurring virus that usurps the activated Ras-signaling pathway (or an element thereof) of tumor cells and lyses them but leaves normal cells relatively unaffected. In this study we evaluated reovirus as an experimental therapeutic in models of central nervous system (CNS) metastasis from breast cancer. We found all breast cancer cell lines tested were susceptible to reovirus, with >50% of these cells lysed within 72 h of infection. In vivo neurotoxicity studies showed only mild local inflammation at the injection site and mild communicating hydrocephalus with neither diffuse encephalitis nor behavioral abnormalities at the therapeutically effective dose of reovirus (intracranial) (ie 107 plaque-forming units) or one dose level higher. In vivo, a single intratumoral administration of reovirus significantly reduced the size of tumors established from two human breast cancer cell lines and significantly prolonged survival. Intrathecal administration of reovirus also remarkably prolonged survival in an immunocompetent racine model of leptomeningeal metastases. These data suggest that the evaluation of reovirus as an experimental therapeutic for CNS metastases from breast cancer is warranted.