A dynamical model of oncotripsy by mechanical cell fatigue: selective cancer cell ablation by low-intensity pulsed ultrasound.

The method of oncotripsy, first proposed in Heyden & Ortiz (Heyden & Ortiz 2016 J. Mech. Phys. Solids 92, 164-175 (doi:10.1016/j.jmps.2016.04.016)), exploits aberrations in the material properties and morphology of cancerous cells in order to ablate them selectively by means of tuned low-intensity pulsed ultrasound. We propose the dynamical model of oncotripsy that follows as an application of cell dynamics, statistical mechanical theory of network elasticity and 'birth-death' kinetics to describe the processes of damage and repair of the cytoskeleton. We also develop a reduced dynamical model that approximates the three-dimensional dynamics of the cell and facilitates parametric studies, including sensitivity analysis and process optimization. We show that the dynamical model predicts-and provides a conceptual basis for understanding-the oncotripsy effect and other trends in the data of Mittelstein et al. (Mittelstein et al. 2019 Appl. Phys. Lett. 116, 013701 (doi:10.1063/1.5128627)), for cells in suspension, including the dependence of cell-death curves on cell and process parameters.

Paediatric case series of drug reaction with eosinophilia and systemic symptoms (DRESS): 12-year experience at a single referral centre in Hong Kong and the first reported use of infliximab.

Summary: DRESS (drug reaction with eosinophilia and systemic symptoms) is a rare but potentially life-threatening disorder characterized by fever, skin eruption, haematological abnormalities and multi-organ dysfunction after drug exposure. The pathophysiology is thought to be related to interactions between culprit drugs, viral reactivation and T-lymphocytes activation. We report 4 paediatric patients with DRESS who were treated at our centre over the past 12 years. Most cases improved after corticosteroids. Other immunosuppressive medications were attempted in refractory cases with varied outcomes. Patient 3 was the first reported case that involved the use of infliximab, a TNF-α inhibitor, for DRESS. Although clinical efficacy was not observed for this one patient, a previous study demonstrated that patients with DRESS, disease progression and HHV-6 reactivation had elevated pre-treatment TNF- α and IL-6 levels. Further research is needed to explore the role of these cytokines in DRESS.

TSG-6 Downregulates IFN-Alpha and TNF-Alpha Expression by Suppressing IRF7 Phosphorylation in Human Plasmacytoid Dendritic Cells.

Proinflammatory cytokines such as TNF-α and type I interferons (IFN) are pathogenic signatures of systemic lupus erythematosus, and plasmacytoid dendritic cells (pDCs) play a major role by predominantly producing IFN-α. Given the rise of importance in identifying tumor necrosis stimulated gene 6 (TSG-6) as a key anti-inflammatory regulator, we investigate its function and its ability to counteract proinflammatory cytokine secretion by pDCs in vitro. CpG-A and R837 induced significant endogenous TSG-6 expression in the pDC cell-line GEN2.2. Following recombinant human TSG-6 treatment and CpG-A or R837 stimulation, significant reduction in IFN-α and TNF-α was observed in healthy donors' pDCs, and the same phenomenon was confirmed in GEN2.2. By CD44 blocking assay, we deduced that the suppressive effect of TSG-6 is mediated by CD44, by reducing IRF-7 phosphorylation. Our findings suggest that TSG-6 and its downstream signalling pathway could potentially be targeted to modulate proinflammatory cytokine expression in pDCs.

Remission With Donor Lymphocyte Infusion in a Child With Marrow Relapse After Haploidentical Stem Cell Transplantation for Relapsed Stage 4 Neuroblastoma.

A 7-year-old male with Stage 4 neuroblastoma was treated with chemotherapy and autologous hematopoietic stem cell transplantation (HSCT), resulting in partial response with residual bone and marrow disease. He proceeded to haploidentical-HSCT with his mother as donor and achieved remission. The patient developed marrow relapse 2 years after haploidentical-HSCT with cytopenia and dropping donor chimerism. Donor lymphocyte infusion (DLI) using mother's whole blood was given resulting in clearance of marrow disease, resolution of cytopenia, and full donor chimerism. This is the first report of successful treatment for neuroblastoma relapse after haploidentical-HSCT using DLI alone, supporting the role of adoptive cell therapy post-HSCT in neuroblastoma.

Exome sequencing identifies novel compound heterozygous mutations of IL-10 receptor 1 in neonatal-onset Crohn's disease.

Inflammatory bowel disease is well recognized for a strong genetic involvement in its pathogenesis. Homozygous mutations in interleukin-10 receptor 1 (IL-10R1) identified by linkage analysis were shown to be involved in this disorder. However, the underlying molecular mechanism and the causal nature of the mutations in the disease process remain to be clarified. In this study, using whole exome sequencing, we identified novel compound heterozygous missense mutations in the extracellular domain of IL-10R1 in a Crohn's disease patient from a non-consanguineous family. These mutations did not affect IL-10R1 expression, nor IL-10 binding. However, they abrogated IL-10R1 phosphorylation induced by IL-10, therefore leading to impaired STAT3 activation and suppression of inflammatory responses. After reconstitution with wild-type IL-10R1, the patient cells showed fully restored IL-10R function including IL-10-induced STAT3 activation and expression of suppressor of cytokine signaling 3. Thus, our results demonstrated that the mutations in IL-10R1 extracellular domain impair IL-10R1 activation rather than IL-10 binding, indicating these residues are important in IL-10 signal transduction through IL-10R1. The reconstitution data also confirmed the causality of the IL-10R1 mutations.

NK cells are dysfunctional in human chronic myelogenous leukemia before and on imatinib treatment and in BCR-ABL-positive mice.

Although BCR-ABL+ stem cells in chronic myeloid leukemia (CML) resist elimination by targeted pharmacotherapy in most patients, immunological graft-versus-leukemia effects can cure the disease. Besides cytotoxic T cells, natural killer (NK) cells may have a role in immune control of CML. Here, we explored the functionality of NK cells in CML patients and in a transgenic inducible BCR-ABL mouse model. Compared with controls, NK-cell proportions among lymphocytes were decreased at diagnosis of CML and did not recover during imatinib-induced remission for 10-34 months. Functional experiments revealed limited in vitro expansion of NK cells from CML patients and a reduced degranulation response to K562 target cells both at diagnosis and during imatinib therapy. Consistent with the results in human CML, relative numbers of NK1.1+ NK cells were reduced following induction of BCR-ABL expression in mice, and the defects persisted after BCR-ABL reversion. Moreover, target-induced degranulation by expanded BCR-ABL+ NK cells was compromised. We conclude that CML is associated with quantitative and functional defects within the NK-cell compartment, which is reproduced by induced BCR-ABL expression in mice. Further work will aim at identifying the mechanisms of NK-cell deficiency in CML and at developing strategies to exploit NK cells for immunotherapy.

Prevention of vaginal SHIV transmission in macaques by a live recombinant Lactobacillus.

Most human immunodeficiency virus (HIV) transmissions in women occur through the cervicovaginal mucosa, which is coated by a bacterial biofilm including Lactobacillus. This commensal bacterium has a role in maintaining a healthy mucosa and can be genetically engineered to produce antiviral peptides. Here, we report a 63% reduction in transmission of a chimeric simian/HIV (SHIV(SF162P3)) after repeated vaginal challenges of macaques treated with Lactobacillus jensenii expressing the HIV-1 entry inhibitor cyanovirin-N. Furthermore, peak viral loads in colonized macaques with breakthrough infection were reduced sixfold. Colonization and prolonged antiviral protein secretion by the genetically engineered lactobacilli did not cause any increase in proinflammatory markers. These findings lay the foundation for an accessible and durable approach to reduce heterosexual transmission of HIV in women, which is coitally independent, inexpensive, and enhances the natural protective effects of the vaginal microflora.

Association of BANK1 and TNFSF4 with systemic lupus erythematosus in Hong Kong Chinese.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease with complex genetic inheritance. Recently, single nucleotide polymorphisms (SNPs) in BANK1 and TNFSF4 have been shown to be associated with SLE in Caucasian populations, but it is not known whether they are also involved in the disease in other ethnic groups. Recent data from our genome-wide association study (GWAS) for 314 SLE cases and 920 controls collected in Hong Kong identified SNPs in and around BANK1 and TNFSF4 to be associated with SLE risk. On the basis of the results of the reported studies and our GWAS, SNPs were selected for further genotyping in 949 SLE patients (overlapping with the 314 cases in our GWAS) and non-overlapping 1042 healthy controls. We confirmed the associations of BANK1 and TNFSF4 with SLE in Chinese (BANK1, rs3733197, odds ratio (OR)=0.84, P=0.021; BANK1, rs17266594, OR=0.61, P=4.67 x 10(-9); TNFSF4, rs844648, OR=1.22, P=2.47 x 10(-3); TNFSF4, rs2205960, OR=1.30, P=2.41 x 10(-4)). Another SNP located in intron 1 of BANK1, rs4522865, was separately replicated by Sequenom in 360 cases and 360 controls and was also confirmed to be associated with SLE (OR=0.725, P=2.93 x 10(-3)). Logistic regression analysis showed that rs3733197 (A383T in ankyrin domain) and rs17266594 (a branch point-site SNP) from BANK1 had independent contributions towards the disease association (P=0.037 and 6.63 x 10(-8), respectively). In TNFSF4, rs2205960 was associated with SLE independently from the effect of rs844648 (P=6.26 x 10(-3)), but not vice versa (P=0.55). These findings suggest that multiple independent genetic variants may be present within the gene locus, which exert their effects on SLE pathogenesis through different mechanisms.

Development of the 25-item National Eye Institute Visual Function Questionnaire.

OBJECTIVE: To develop and test the psychometric properties of a 25-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25). DESIGN: Prospective observational cohort study of persons with 1 of 5 chronic eye diseases or low vision who were scheduled for nonurgent visits in ophthalmology practices and a reference sample of persons without eye disease. SETTING: Eleven university-based ophthalmology practices and the NEI Clinical Center. PATIENTS: Eligible participants had to have 1 of the following eye conditions: age-related cataracts, age-related macular degeneration, diabetic retinopathy, primary open-angle glaucoma, cytomegalovirus retinitis, or low vision from any cause. Seven of the 12 sites also enrolled persons in a reference sample. Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error. All eligible persons had to be 21 years or older, English speaking, and cognitively able to give informed consent and participate in a health status interview. MEASUREMENTS AND MAIN RESULTS: To provide the data needed to create the NEI VFQ-25, all subjects completed an interview that included the 51-item NEI VFQ. Estimates of internal consistency indicate that the subscales of the NEI VFQ-25 are reliable. The validity of the NEI VFQ-25 is supported by high correlations between the short- and long-form versions of the measure, observed between-group differences in scores for persons with different eye diseases of varying severity, and the moderate-to-high correlations between the NEI VFQ-25 subscales that have the most to do with central vision and measured visual acuity. CONCLUSIONS: The reliability and validity of the NEI VFQ-25 are comparable to those of the 51-item NEI VFQ field test version of the survey. This shorter version will be more feasible in settings such as clinical trials where interview length is a critical consideration. In addition, preliminary analyses indicate that the psychometric properties of the NEI VFQ-25 are robust for the eye conditions studied; this suggests that the measure will provide reproducible and valid data when used across multiple conditions of varying severity.

A comparison of two types of dendritic cell as adjuvants for the induction of melanoma-specific T-cell responses in humans following intranodal injection.

Dendritic cells (DCs) elicit potent anti-tumoral T-cell responses in vitro and in vivo. However, different types of DC have yet to be compared for their capacity to induce anti-tumor responses in vivo at different developmental stages. Herein, we correlated the efficiencies of different types of monocyte-derived DC as vaccines on the resulting anti-tumor immune responses in vivo. Immature and mature DCs were separately pulsed with a peptide derived from tyrosinase, MelanA/MART-1 or MAGE-1 and a recall antigen. Both DC populations were injected every 2 weeks in different lymph nodes of the same patient. Immune responses were monitored before, during and after vaccination. Mature DCs induced increased recall antigen-specific CD4(+) T-cell responses in 7/8 patients, while immature DCs did so in only 3/8. Expansion of peptide-specific IFN-gamma-producing CD8(+) T cells was observed in 5/7 patients vaccinated with mature DCs but in only 1/7 using immature DCs. However, these functional data did not correlate with the tetramer staining. Herein, immature DCs also showed expansion of peptide-specific T cells. In 2/4 patients vaccinated with mature DCs, we observed induction of peptide-specific cytotoxic T cells, as monitored by chromium-release assays, whereas immature DCs failed to induce peptide-specific cytotoxic T cells in the same patients. Instead, FCS-cultured immature DCs induced FCS-specific IgE responses in 1 patient. Our data demonstrate that this novel vaccination protocol is an efficient approach to compare different immunization strategies within the same patient. Thus, our data define FCS-free cultured mature DCs as superior inducers of T-cell responses in melanoma patients.

Regulation of milk protein gene expression in normal mammary epithelial cells by tumor necrosis factor.

Tumor necrosis factor-alpha (TNF) is a physiologically significant regulator of mammary gland development, stimulating growth and branching morphogenesis of mammary epithelial cells (MEC) and modulating functional differentiation. The present studies were performed to determine the mechanism by which TNF modulated functional differentiation. In rat MEC in primary culture, TNF inhibited accumulation of whey acidic protein and beta-casein messenger RNAs in a time- and concentration-dependent manner. In contrast, levels of transferrin messenger RNA, the product of another milk protein gene, were not inhibited by TNF, suggesting selectivity. Using a nuclear run-on assay in the immortalized HC11 mammary epithelial cell line and the transcriptional inhibitor actinomycin D in MEC in primary culture, the effects of TNF were shown to be mediated by both a decrease in transcription and a decrease in the stability of the whey acidic protein and beta-casein transcripts. Additionally, TNF stimulated the binding of nuclear factor-kappaB to a consensus kappaB-oligonucleotide, increased the stability of matrix metalloproteinase-9 (MMP-9) transcripts, and increased MMP-9 activity. Together, these data suggest that TNF may exert its effects on milk protein gene expression either directly via nuclear factor-kappaB modulation of transcription, or indirectly via MMP-9-induced remodeling of the architectural or hormonal environment surrounding the MEC.

Functional role of matrix metalloproteinases (MMPs) in mammary epithelial cell development.

The extracellular matrix (ECM) is an important regulator of mammary epithelial cell (MEC) function and is remodeled by matrix metalloproteinases (MMPs). To investigate the significance and regulation of MMP activity in normal MEC, we utilized a primary culture model in which rat MEC were grown three dimensionally within a reconstituted basement membrane (RBM) in defined serum-free medium. Zymograms of culture medium demonstrated that five major gelatinases of 97, 80, 74, 69, and 65 kDa were secreted by MEC and were distinct from gelatinases of RBM origin. Based on molecular weight, p-aminophenylmercuric acid activation, immunoblotting with MMP-specific antibodies, inhibition by EDTA, a peptide containing the prodomain sequence of MMP (TMRKPRCGNPDVAN) and two synthetic MMP inhibitors (BB-94 and CGS 27023A), these were classified as inactive and active forms of MMP-9 and MMP-2. The maximal MMP activities occurred when MEC were in a rapid proliferation and branching phase and declined after they underwent functional differentiation. Known regulators of MEC growth and differentiation were evaluated for their ability to modulate gelatinase activity in primary culture. Secretion of one or both MMPs was inhibited by EGF, TGFalpha, prolactin, and hydrocortisone and stimulated by progesterone. Furthermore, the functional significance of MMPs was demonstrated since three MMP inhibitors blocked branching morphogenesis elicited by the absence of hydrocortisone. Additionally, two synthetic MMP inhibitors not only inhibited epithelial cell growth but also inhibited normal alveolar development of the MEC. Finally, these drugs were found to enhance MMP secretion from MEC, although the activity of the secreted MMPs was inhibited as long as the drug was present.

Methods for Use of Peptide-MHCTetramers in Tumor Immunology.

Direct analysis of T-cells of defined specificity and phenotype, without in vitro manipulation that accompanies limiting dilution analysis or other restimulation protocols for evaluating precursor frequency, provides the most accurate representation possible of in vivo events. The natural ligand of the T-cell receptor (TCR), the peptide-major histocompatibility, could be used to identify T-cells of a given specificity, but the use of a single peptide-MHC would fail because the affinity of the peptide-MHC for its TCR ligand is characterized by a very fast dissociation rate (1,2). A tetrameric peptide-MHC, however, exhibits sufficient affinity for its TCR ligand to permit its use as a staining reagent in flow cytometry so that peptide-specific T-cells can be visualized by fluorescent markers conjugated to the tetramer (3,4). By combining this approach with fluorescent antibodies staining phenotypic markers or intra- cellular cytokines, this novel and powerful technology now provides a more rapid and informative assessment of antigen-specific T-cells in a given population. Furthermore, sorting individual tetramer+ cells provides an expeditious means for detailed single cell analysis or sorting followed by in vitro expansion. We and others have demonstrated that peptide-MHC tetramers can be used for the purposes discussed in the next sections.

Melanocyte destruction after antigen-specific immunotherapy of melanoma: direct evidence of t cell-mediated vitiligo.

Current strategies for the immunotherapy of melanoma include augmentation of the immune response to tumor antigens represented by melanosomal proteins such as tyrosinase, gp100, and MART-1. The possibility that intentional targeting of tumor antigens representing normal proteins can result in autoimmune toxicity has been postulated but never demonstrated previously in humans. In this study, we describe a patient with metastatic melanoma who developed inflammatory lesions circumscribing pigmented areas of skin after an infusion of MART-1-specific CD8(+) T cell clones. Analysis of the infiltrating lymphocytes in skin and tumor biopsies using T cell-specific peptide-major histocompatibility complex tetramers demonstrated a localized predominance of MART-1-specific CD8(+) T cells (>28% of all CD8 T cells) that was identical to the infused clones (as confirmed by sequencing of the complementarity-determining region 3). In contrast to skin biopsies obtained from the patient before T cell infusion, postinfusion biopsies demonstrated loss of MART-1 expression, evidence of melanocyte damage, and the complete absence of melanocytes in affected regions of the skin. This study provides, for the first time, direct evidence in humans that antigen-specific immunotherapy can target not only antigen-positive tumor cells in vivo but also normal tissues expressing the shared tumor antigen.

Functional significance of MMP-9 in tumor necrosis factor-induced proliferation and branching morphogenesis of mammary epithelial cells.

Tissue remodeling is a key process involved in normal mammary gland development, with matrix metalloproteinases (MMPs) playing an important role in this process. Our laboratory has demonstrated that tumor necrosis factor (TNF) stimulates branching morphogenesis of mammary epithelial cells (MEC) within a reconstituted basement membrane. Studies were therefore undertaken to determine whether MMPs might mediate the effects of TNF. Using a primary culture model in which rat MEC grow three-dimensionally within a reconstituted basement membrane, we found that TNF stimulated secretion of MMP-9 but not MMP-2. To determine whether MMP-9 was involved in TNF-induced proliferation and branching morphogenesis, we used a peptide containing the prodomain sequence of MMPs and two MMP inhibitors. Both the prodomain peptide (5 x 10(-4)-10(-3) M), as well as BB-94 (10(-8)-10(-5) M) and CGS 27023A (10(-6)-10(-5) M), inhibited TNF-induced proliferation and branching morphogenesis in a concentration-dependent manner. Finally, to verify the specific requirement for MMP-9, we demonstrated that an MMP-9 neutralizing antibody blocked TNF-induced proliferation and branching morphogenesis. Together, these data suggest that TNF-regulated MMP-9 may play a role in the controlled invasion of the fad pad that occurs during normal mammary gland development and that misregulation of MMP-9 may contribute to the invasiveness of breast cancer.

Evidence that specific T lymphocytes may participate in the elimination of chronic myelogenous leukemia.

Although the immune system has long been implicated in the control of cancer, evidence for specific and efficacious immune responses in human cancer has been lacking. In the case of chronic myelogenous leukemia (CML), either allogeneic bone marrow transplant (BMT) or interferon-alpha2b (IFN-alpha2b) therapy can result in complete remission, but the mechanism for prolonged disease control is unknown and may involve immune anti-leukemic responses. We previously demonstrated that PR1, a peptide derived from proteinase 3, is a potential target for CML-specific T cells. Here we studied 38 CML patients treated with allogeneic BMT, IFN- alpha2b or chemotherapy to look for PR1-specific T cells using PR1/HLA-A*0201 tetrameric complexes. There was a strong correlation between the presence of PR1-specific T cells and clinical responses after IFN-alpha and allogeneic BMT. This provides for the first time direct evidence of a role for T-cell immunity in clearing malignant cells.

The use of HLA A2.1/p53 peptide tetramers to visualize the impact of self tolerance on the TCR repertoire.

p53 is an attractive target for cancer immunotherapy since it is overexpressed in half of all tumors. However, it is also expressed in normal lymphoid tissue, and self tolerance leaves a p53-specific repertoire purged of high avidity CTL. To better understand the mechanism of tolerance and the basis for such low avidity interaction, p53-specific CTL from p53 deficient (p53-) and sufficient (p53+) A2.1/Kb transgenic mice were compared with respect to their ability to bind HLA-A2.1 tetramers containing cognate murine p53 peptide Ag, p53 261-269. Since the murine CD8 molecule cannot interact with human HLA-A2.1, this tests the ability of the TCR to bind the A2.1/peptide complex tetramer. CTL from p53- mice demonstrated strong binding of such A2.1/p53 261-269 tetramers; however, the CTL from tolerant p53+ mice were devoid of tetramer-binding CD8+ T cells. Examination of TCR expression at the clonal level revealed that CTL from p53+ and p53- mice each expressed comparable levels of the p53-specific TCR. These results indicate that normal expression of p53 promotes elimination of T cells expressing TCRs with sufficient affinity to achieve stable binding of the A2.1/p53 261-269 tetramers.

Mammary fibroblasts stimulate growth, alveolar morphogenesis, and functional differentiation of normal rat mammary epithelial cells.

Stromal-epithelial interactions play a profound role in regulating normal and tumor development in the mammary gland. The molecular details of these events, however, are incompletely understood. A novel serum-free transwell coculture system was developed to study the natural paracrine interactions between mammary epithelial cells (MEC) and mammary fibroblasts (MFC) isolated from normal rats during puberty. The MEC were cultured within a reconstituted basement membrane (RBM) in transwell inserts with or without MFC in the lower well. The presence of MFC stimulated epithelial cell growth, induced alveolar morphogenesis, and enhanced casein accumulation, a marker of the functional differentiation of MEC, but did not induce ductal morphogenesis. Potent mitogenic, morphogenic, and lactogenic effects were observed when the MFC were cultured either on plastic or within a layer of RBM. Although most MFC maintained on plastic died after 1 wk in serum-free medium, fibroblast survival was enhanced significantly when the MFC were cultured within the RBM. Taken together, this in vitro model effectively reconstitutes a physiologically relevant three-dimensional microenvironment for MEC and MFC, and seems ideal for studying the locally derived factors that regulate the developmental fate of the epithelial and fibroblast compartments of the mammary gland.

TGFbeta1 stimulates the secretion of matrix metalloproteinase 2 (MMP2) and the invasive behavior in human ovarian cancer cells, which is suppressed by MMP inhibitor BB3103.

The present study investigated the modulatory role of transforming growth factor beta 1 (TGFbeta1) on the secretion of matrix metalloproteinases (MMPs) and tested whether the altered secretion of MMPs could directly affect the invasive behavior of ovarian cancer cells. To this aim, human ovarian cancer SKOV3 cells were treated once with vehicle or various concentrations of TGFbeta1 for 24 h. Gelatinase activities in conditioned media were analyzed by zymography and densitometry. TGFbeta1 dose-dependently stimulated the secretion of a 68-kDa gelatinase, which was characterized as an MMP because its activity was inhibited by a metalloproteinase inhibitor 1,10-phenanthroline, and by a synthetic MMP inhibitor BB3103. In addition, we used aminophenylmercuric acetate (APMA) to activate latent gelatinases. APMA time-dependently decreased the activity of 68-kDa gelatinase, and increased the activities of 64- and 62-kDa gelatinolytic bands. The 68-kDa gelatinase was further characterized as MMP2 (gelatinase A) by immunoblotting analysis. We then tested TGFbeta1 effect on the invasive potential of SKOV3 cells as assessed by the migration ability through reconstituted basement membrane, and further investigated whether TGFbeta1 may act through modulating the MMP activity to affect ovarian cancer cell invasion. The results show that TGFbeta1 stimulated the invasive behavior of SKOV3 cells, and that MMP inhibitor BB3103 abrogated this effect of TGFbeta1. In conclusion, this study indicates that TGFbeta1 may act partly through stimulating the secretion of MMP in promoting the invasive behavior of human ovarian cancer cells. Furthermore, this work supports the idea that specific MMP inhibitors of the hydroxamate class could be therapeutically useful in controlling cancer cell invasion/metastasis.