Effect of cisplatin and BCNU on MMP-2 levels in human glioblastoma cell lines in vitro

Platinum-Based Nanoformulations for Glioblastoma Treatment: The Resurgence of Platinum Drugs?

Current therapies for treating Glioblastoma (GB), and brain tumours in general, are inefficient and represent numerous challenges. In addition to surgical resection, chemotherapy and radiotherapy are presently used as standards of care. However, treated patients still face a dismal prognosis with a median survival below 15-18 months. Temozolomide (TMZ) is the main chemotherapeutic agent administered; however, intrinsic or acquired resistance to TMZ contributes to the limited efficacy of this drug. To circumvent the current drawbacks in GB treatment, a large number of classical and non-classical platinum complexes have been prepared and tested for anticancer activity, especially platinum (IV)-based prodrugs. Platinum complexes, used as alkylating agents in the anticancer chemotherapy of some malignancies, are though often associated with severe systemic toxicity (i.e., neurotoxicity), especially after long-term treatments. The objective of the current developments is to produce novel nanoformulations with improved lipophilicity and passive diffusion, promoting intracellular accumulation, while reducing toxicity and optimizing the concomitant treatment of chemo-/radiotherapy. Moreover, the blood-brain barrier (BBB) prevents the access of the drugs to the brain and accumulation in tumour cells, so it represents a key challenge for GB management. The development of novel nanomedicines with the ability to (i) encapsulate Pt-based drugs and pro-drugs, (ii) cross the BBB, and (iii) specifically target cancer cells represents a promising approach to increase the therapeutic effect of the anticancer drugs and reduce undesired side effects. In this review, a critical discussion is presented concerning different families of nanoparticles able to encapsulate platinum anticancer drugs and their application for GB treatment, emphasizing their potential for increasing the effectiveness of platinum-based drugs.

The antiangiogenic action of cisplatin on endothelial cells is mediated through the release of tissue inhibitor of matrix metalloproteinases-1 from lung cancer cells

In addition to suppressing cancer cell proliferation and tumor growth, cisplatin has been shown to inhibit tumor angiogenesis. However, the underlying mechanism remains a matter of debate. The present study addressed the impact of cisplatin on potential tumor-to-endothelial cell communication conferring an antiangiogenic effect. For this purpose, migration and tube formation of human umbilical vein endothelial cells (HUVECs) exposed to conditioned media (CM) from vehicle- or cisplatin-treated A549 and H358 lung cancer cells were quantified. Cancer cells were exposed to non-toxic concentrations of cisplatin to mimic low-dose treatment conditions. CM from cancer cells exposed to cisplatin at concentrations of 0.01 to 1 µM elicited a concentration-dependent decrease in HUVEC migration and tube formation as compared with CM from vehicle-treated cells. The viability of HUVECs was virtually unaltered under these conditions. siRNA approaches revealed cisplatin-induced expression and subsequent release of tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) by lung cancer cells to be causally linked to a decrease in HUVEC migration and tube formation. Moreover, TIMP-1 upregulation and consequent inhibition of HUVEC migration by cisplatin was shown to be dependent on activation of p38 and p42/44 mitogen-activated protein kinases. Inhibition of angiogenic features was not observed when HUVECs were directly exposed to cisplatin. Similarly, antiangiogenic effects were not detectable in HUVECs exposed to CM from the cisplatin-challenged bronchial non-cancer cell line BEAS-2B. Collectively, the present data suggest a pivotal role of cisplatin-induced TIMP-1 release from lung cancer cells in tumor-to-endothelial cell communication resulting in a reduced cancer-associated angiogenic impact on endothelial cells.

Repurposing platinum-based chemotherapies for multi-modal treatment of glioblastoma

Glioblastoma (GBM) is a fatal brain cancer for which new treatment options are sorely needed. Platinum-based drugs have been investigated extensively for GBM treatment but few have shown significant efficacy without major central nervous system (CNS) and systemic toxicities. The relative success of platinum drugs for treatment of non-CNS cancers indicates great therapeutic potential when effectively delivered to the tumor region(s). New insights into the broad anticancer effects of platinum drugs, particularly immunomodulatory effects, and innovative delivery strategies that can maximize these multi-modal effects and minimize toxicities may promote the re-purposing of this chemotherapeutic drug class for GBM treatment.

Collagen-hydroxyapatite/cisplatin drug delivery systems for locoregional treatment of bone cancer

In this paper, the synthesis and characterization of novel cisplatin-loaded collagen (COLL)/hydroxyapatite (HA) composite materials are presented. The composite materials were designed to obtain a COLL: HA weight ratio close to the bone composition. The content of embedded cisplatin was chosen to assure a concentration of cisplatin of 6 and 10 μM, respectively, into the culture media used in cell culture experiments. These cisplatin delivery systems were characterized by determining the physico-chemical properties of the composite material, the drug release process as well as their biological activity. Based on the in vitro data that showed the cytotoxic, anti-proliferative and anti-invasive activities of these multifunctional systems on G292 osteosarcoma cells in dependence on the cisplatin concentration released in culture medium, we conclude that the newly developed COLL/HA-cisplatin drug delivery system could be a feasible approach for locoregional chemotherapy of bone cancer.

Synthesis, structure and characterization of novel Cd(II) and Zn(II) complexes with the condensation product of 2-formylpyridine and selenosemicarbazide Antiproliferative activity of the synthesized complexes and related selenosemicarbazone complexes

Two novel Cd(II) and Zn(II) complexes with the condensation product of 2-formylpyridine and selenosemicarbazide were synthesized. The structure of Cd(II) complex was determined by X-ray crystallography. The ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms and the selenium donor. The cadmium ion completes its five-coordination by two chloride ligands, forming a square-pyramidal geometry. The structure of Zn(II) complex was established by analysis of spectroscopic data, which indicated coordination of the ligand as a bidentate via the selenium and the azomethine nitrogen atoms. The cytotoxic activity of the newly synthesized complexes, as well as if five structurally related complexes and the ligand evaluated against eight tumor cell lines. The new Cd(II) complex showed the highest activity similar to cisplatin with IC50 less than 10muM for all cell lines. Cell cycle distribution and apoptosis study showed that Cd(II) complex and cisplatin might have some similarity in anticancer activity, which was not the case for cisplatin and other studied complexes. Effects of the complexes on matrix metalloproteinases (MMPs) MMP-9 and MMP-2 was also studied. Cd(II) and Zn(II) complexes and cisplatin increased MMP-2 activity in supernatants of tested cells, while Ni(II) complex with the same ligand decreased the activity, implying a possible activity in preventing tumor invasion and metastasis processes.

Effects of cisplatin on matrix metalloproteinase-2 in transformed thyroid cells

We investigated the effects of cisplatin (cisPt) on matrix metalloproteinase-2 (MMP-2) gelatinolitic activity in transformed PC E1Araf rat thyroid cells. Cells incubated with increasing cisPt concentrations showed dose- and time-dependent decrease of the MMP-2 protein and activity. CisPt provoked the translocation from the cytosol to the plasma membrane of atypical protein kinase C-zeta (PKC-zeta) and the activation of PKB/AKT. The effect of cisPt on MMP-2 was dependent on PKC-zeta activation since it was potentiated by a myristoylated PKC-zeta pseudo substrate peptide or by PKC-zeta down-regulation by siRNA. Moreover, MMP-2 activity modulation by cisPt was also dependent on PKB/AKT activation since it was decreased by PKB/AKT down-regulation by siRNA or by pharmacological inhibition of PI3K, thus indicating the importance of the balance of PKB/AKT and PKC-zeta in regulating the cisPt effect on MMP-2 activity. The PC E1Araf cells displayed a migratory capacity that was blocked by MMP-2 down-regulation using siRNA or pharmacological inhibition. The inhibition of cell migration was also obtained with cisPt; in cisPt-treated cells the administration of MMP-2 active protein was able to restore cell migration capacity. In conclusion, the decrease of MMP-2 secretion after cisPt was allowed by PKB/AKT and counteracted by PKC-zeta; the cisPt-provoked inhibition of MMP-2 secretion ended in reduction of cell migration.

Prognostic significance of c-Met expression in glioblastomas

BACKGROUND

The authors investigated whether expression of c-Met protein in glioblastomas is associated with overall survival and biologic features representing tumor invasiveness in patients with glioblastomas.

METHODS

Paraffin-embedded specimens of glioblastomas from 62 patients treated in a single institution were assessed by immunohistochemical (IHC) analysis of c-Met expression. On the basis of the clinical data for these patients, the association between c-Met expression and clinicobiologic features representing tumor invasiveness was analyzed.

RESULTS

c-Met overexpression was detected in 29.0% (18 of 62) of glioblastomas. In patients with c-Met overexpression, the median survival was 11.7 months (95% confidence interval [95% CI], 9.9 months-13.5 months), compared with a median survival of 14.3 months (95% CI, 7.6 months-21.0 months) for patients whose tumors had no or little expression of c-Met (P=.031). On the radiographic analysis, 9 of 18 patients (50%) with tumors overexpressing c-Met demonstrated invasive and multifocal lesions on the initial magnetic resonance images, whereas only 9 of 44 patients (20.5%) with tumors that expressed no or little c-Met demonstrated these features (P=.030). Using immunohistochemistry, we also found a significant association between c-Met expression and matrix metalloproteinase-2,-9 (P=.020 and P=.013). Furthermore, Myc overexpression was found to be closely correlated with c-Met overexpression on IHC analysis (P=.004).

CONCLUSIONS

The authors suggest that c-Met overexpression is associated with shorter survival time and poor treatment response in glioblastomas, the mechanism for which is elevated tumor invasiveness on the molecular and clinical phenotypes. This implies that more effective therapeutic strategies targeting c-Met receptors may have important clinical implication.

Enhancement of cisplatin efficacy by thalidomide in a 9L rat gliosarcoma model

With the aim of improving the treatment of glioblastoma multiforme, we investigated the potential of thalidomide to enhance the effectiveness of cisplatin chemotherapy in a rat glioma model. Female F344 rats were implanted with 9L gliosarcoma tumors either intracranially or subcutaneously and treated with 1 mg/kg cisplatin injected i.p. or with 1% thalidomide in the food or with these treatments combined. Cisplatin in combination with thalidomide significantly reduced both the subcutaneous tumor volume at 30 days to 22 +/- 5% (mean +/- SEM, P < 0.001) and the intracranial tumor volume at 18 days to 44 +/- 15% (P < 0.05) of that with cisplatin alone. Thalidomide selectively increased the cisplatin concentration 10-fold in intracranial tumors (P < 0.05) and 2-fold in the subcutaneous tumors (P < 0.05) without increasing its concentration in major organs including brain and kidney. Cisplatin combined with thalidomide caused a significant decrease in vascular endothelial growth factor (VEGF) levels by 73% in intracranial tumors (P < 0.05) and by 50% in subcutaneous tumors (P < 0.05) and caused the level of active hepatic growth factor (a-HGF) to double in both the subcutaneous and intracranial tumors (P < 0.05), suggesting this treatment altered the vasculature in these tumors. We conclude the increased efficacy of cisplatin in the presence of thalidomide was due to the selective increase in cisplatin concentration within the tumors and speculate that this is the result of thalidomide or the cisplatin/thalidomide combination, selectively altering the tumor vasculature. Based on the selective effects of thalidomide on tumor cisplatin concentrations and the resulting increase in efficacy, thalidomide may also increase the efficacy of other drugs that are presently considered ineffective against glioma.

Upregulation of tissue inhibitor of matrix metalloproteinases-1 confers the anti-invasive action of cisplatin on human cancer cells

Cancer cell invasion is one of the crucial events in local spreading, growth and metastasis of tumors. The present study investigates the mechanism underlying the anti-invasive action of the chemotherapeutic cisplatin. In human cervical carcinoma cells (HeLa), cisplatin caused a time- and concentration-dependent suppression of cell invasion through Matrigel. Inhibition of invasion was accompanied by upregulation of tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), whereas levels of matrix metalloproteinase-2 (MMP-2), MMP-9 and TIMP-2 remained unchanged. Cisplatin's effects on TIMP-1 expression and invasion were associated with phosphorylations of p38 and p42/44 mitogen-activated protein kinases and were abrogated by specific inhibitors of both pathways. The impact of TIMP-1 in the anti-invasive action of cisplatin was proven by transfecting cells with small interfering RNA targeting TIMP-1, which completely reversed suppression of invasion by cisplatin. A functional relevance of TIMP-1 upregulation was substantiated by findings showing a concentration-dependent inhibition of Matrigel invasion by recombinant TIMP-1. The essential role of TIMP-1 in the anti-invasive action of cisplatin was confirmed using another human cervical carcinoma cell line (C33A) and human lung carcinoma cells (A549). Altogether, our data demonstrate a hitherto unknown mechanism by which cisplatin exerts its antimetastatic properties on highly invasive cancer cells.

Synthesis and characterization of a novel Pd(II) complex with the condensation product of 2-(diphenylphosphino)benzaldehyde and ethyl hydrazinoacetate. Cytotoxic activity of the synthesized complex and related Pd(II) and Pt(II) complexes

A new palladium(II) complex 1 of the condensation product of 2-(diphenylphosphino)benzaldehyde (dpba) and ethyl hydrazinoacetate (etha) was synthesized and characterized by elemental analyses, IR, and (1)H NMR spectroscopy. The bound ligand is a bidentate (PN chromophore), the remaining two coordination places being occupied by chloride ions in overall square planar geometry. The cytotoxic activity of the complex 1 and two related Pd(II) and Pt(II) complexes 2 and 3 was tested against a panel of four tumor cell lines. The activity of the complexes was similar to that of cisplatin, the most widely used metal-based antitumor drug. It is important to notice that complexes 2 and 3 were active to cisplatin-resistant U2-OS/Pt cells. Cell cycle alteration investigation, apoptotic assay and gelatin zymography in relation to invasion and metastasis of tumor cells, were performed with all the investigated complexes on Human cervix carcinoma (HeLa) cells. The results suggest that 1 has a similar effect to cisplatin, inducing apoptosis followed by arrest of cells in S phase of cell cycle, while 2 and 3 induce apoptosis without significant perturbations of cell cycle distribution.

Redefining the target: chemotherapeutics as antiangiogenics

Angiogenesis, or new blood vessel formation, is now known to play an important role in both growth and metastasis of many cancers. The central importance of angiogenesis and the understanding of how new blood vessels are formed, has led to novel therapies designed to interrupt this process. Though specific antiangiogenic compounds have only recently entered the clinic, they herald a new era, one in which biology is the basis for therapy. The intense interest in angiogenesis has also lead to a re-examination of the activity of many established cytotoxic agents. Claims of antiangiogenic activity abound, unfortunately, with no common criteria and often little evidence of clinical relevance. What are we to think? Have oncologists unknowingly been administering antiangiogenic therapy all these years? If chemotherapeutics are really antiangiogenics in disguise, why have they failed to cure most solid tumors? Might the hard-learned lessons of chemotherapy resistance pertain to the novel antiangiogenics as well? Though we can offer no certain answers to these important questions, we do offer a framework on which to order the rapidly burgeoning literature. We suggest criteria by which a cytotoxic agent might reasonably be considered to have meaningful antiangiogenic activity. Finally, we describe potential mechanisms of resistance to antiangiogenic chemotherapies-some of which may apply to the pure antiangiogenics currently in development.

Effects of radiation on a model of malignant glioma invasion

We sought to characterize the effects of radiation alone and in combination with BCNU and dexamethasone on malignant glioma invasion. A model of malignant glioma invasion into a gel matrix of collagen type I was used to characterize response to radiation treatment for four malignant glioma cell lines (C6, U251, U373, A172) and nine primary human glioblastoma explants. A radiation dose dependent inhibition of invasion was noted for the C6 astrocytoma cell line but not the other cell lines or explants. Addition of BCNU and dexamethasone to radiation produced additional inhibition of invasion among the cell lines and explants but could not suppress invasion entirely.

Elevated levels of Mr 92,000 type IV collagenase during tumor growth in vivo

Our previous studies demonstrated that matrix metalloproteinase (MMP-9) levels were significantly higher in human glioblastoma tissue samples than in low-grade brain tumors and normal brain tissue (Rao et al., Cancer Res. 53, 2208-2211, 1993). In the present study, we measured the levels of MMP-2 and MMP-9 during the growth of glial tumors in nude mice by intracerebral injection of glioblastoma cells. Using gelatin zymography, densitometry, and an enzyme-linked immunosorbent assay, we found that the enzyme activity and protein count of MMP-2 and MMP-9 were a respective 3- to 10- and 2- to 30-fold higher in tumors at day 14 and 28 than in normal tissue. Immunohistochemical staining for MMP-9 showed strong immunoreactivity in tumor cells and the staining intensity was much higher at day 28, compared to day 14. These results suggest that upregulation of MMP-9 plays a major role in the glioma tumor growth in vivo.