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Cerebrospinal fluid matrix metalloproteinase-9 increases during treatment of recurrent malignant gliomas
Eric T Wong1, David Alsop, Diana Lee
1Beth Israel Deaconess Medical Center, Brain Tumor Center & Neuro-Oncology Unit, Boston, MA 02215, USA. ewong@bidmc.harvard.edu.
Background:
Matrix metalloproteinases (MMPs) are enzymes that promote tumor invasion and angiogenesis by enzymatically remodeling the extracellular matrix. MMP-2 and MMP-9 are the most abundant forms of MMPs in malignant gliomas, while a 130 kDa MMP is thought to be MMP-9 complexed to other proteinases. This study determined whether doxycycline can block MMP activity in vitro. We also measured MMP-2 and MMP-9 levels in cerebrospinal fluid (CSF) from patients with recurrent malignant gliomas.
Methods:
To determine whether doxycycline can block MMP activity, we measured the extent of doxycyline-mediated MMP-2 and MMP-9 inhibition in vitro using epidermal growth factor receptor (EGFR) transfected U251 glioma cell lines. MMP activity was measured using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) zymography. In addition, patients underwent lumbar puncture for CSF sampling at baseline, after 6 weeks (1 cycle), and after 12 weeks (2 cycles), while being treated with a novel chemotherapy regimen of irinotecan, thalidomide, and doxycycline designed to block growth/proliferation, angiogenesis, and invasion. Irinotecan was given at 125 mg/m2/week for 4 weeks in 6-week cycles, together with continuous doxycycline at 100 mg twice daily on Day 1 and 50 mg twice daily thereafter. Daily thalidomide dose in our cohort was 400 mg. Tumor progression was monitored by magnetic resonance imaging (MRI).
Results:
Doxycyline in vitro completely abolished MMP-9 activity at 500 mug/ml while there was only 30 to 50% inhibition of MMP-2 activity. Four patients respectively completed 4, 3, 1, and 2 cycles of irinotecan, thalidomide, and doxycycline. Patient enrollment was terminated after one patient developed radiologically defined pulmonary embolism, and another had probable pulmonary embolism. Although CSF MMP-2 and 130 kDa MMP levels were stable, MMP-9 level progressively increased during treatment despite stable MRI.
Conclusion:
Doxycycline can block MMP-2 and MMP-9 activities from glioma cells in vitro. Increased CSF MMP-9 activity could be a biomarker of disease activity in patients with malignant gliomas, before any changes are detectable on MRI.
Insights
Doxycycline effectively inhibited matrix metalloproteinase-9 (MMP-9) in glioma cells, but increased MMP-9 levels in cerebrospinal fluid suggest it may indicate disease activity before MRI changes.
Area of Science:
- Oncology
- Biochemistry
- Pharmacology
Background:
- Matrix metalloproteinases (MMPs) remodel the extracellular matrix, promoting tumor invasion and angiogenesis.
- MMP-2 and MMP-9 are prevalent in malignant gliomas, with a 130 kDa MMP possibly representing MMP-9 complexes.
- This study investigated doxycycline's potential to inhibit MMP activity and its impact on glioma patients.
Purpose of the Study:
- To evaluate the in vitro efficacy of doxycycline in blocking MMP-2 and MMP-9 activity.
- To assess MMP-2 and MMP-9 levels in cerebrospinal fluid (CSF) of patients with malignant gliomas undergoing a specific chemotherapy regimen.
Main Methods:
- Doxycycline's inhibition of MMP-2 and MMP-9 was measured in EGFR-transfected U251 glioma cells using SDS-PAGE zymography.
- Patients received a combination chemotherapy of irinotecan, thalidomide, and doxycycline.
- CSF samples were collected at baseline, 6 weeks, and 12 weeks; tumor progression was monitored via MRI.
Main Results:
- Doxycycline completely inhibited MMP-9 activity in vitro at 500 µg/ml, with 30–50% inhibition of MMP-2.
- Patient enrollment was halted due to pulmonary embolism events in two participants.
- CSF MMP-9 levels increased during treatment, despite stable MRI findings and stable CSF MMP-2 and 130 kDa MMP levels.
Conclusions:
- Doxycycline demonstrated in vitro efficacy in blocking MMP-2 and MMP-9 activities from glioma cells.
- Elevated CSF MMP-9 may serve as an early biomarker for malignant glioma disease activity, preceding detectable MRI changes.
