Response of short-term cultures derived from human malignant glioma to aziridinylbenzoquinone, etoposide and doxorubicin: an in vitro phase II trial

Modification of graphene oxide by angiopep-2 enhances anti-glioma efficiency of the nanoscaled delivery system for doxorubicin

OBJECTIVE

This study aimed to evaluate the efficacy of the improved nanoscaled delivery system for doxorubicin (Dox) based on angiopep (ANG)-2 modified graphene oxide (GO), the so-called ANG-Dox-GO, in suppressing the growth and and metastasis of glioma cells.

RESULTS

Modification of GO by angiopep-2 significantly increased the cellular uptake of Dox. In addition, ANG-Dox-GO treatment of U87 MG cells significantly inhibited cell viability, decreased clone number, cell migration and invasion andinduced cell apoptosis, with superior efficiency over that of Dox-GO and free Dox. Similar results were observed in in vivo experiments-tumor size and weight of glioma xenograft mice were obviously decreased after treatments with ANG-Dox-GO, Dox-GO and Dox, respectively, as compared with control group, and the efficiency was the highest in ANG-Dox-GO, followed by Dox-Go and Dox.

CONCLUSIONS

ANG-Dox-GO exhibited superior anti-glioma effects over Dox-GO both in vitro and in vivo experiments.

METHODS

The morphology of ANG-Dox-GO was analyzed by UV visible absorption spectroscopy and atomic force microscopy and its in vitro cellular uptake was measured using confocal imaging analysis. The antitumor effects of GO, unbound Dox, Dox-GO and ANG-Dox-GO were evaluated by MTT assay, colony-forming assay, cell apoptosis assay and Transwell assay in U87 malignant glioma (MG) cells.

Topoisomerase II Poisons for Glioblastoma; Existing Challenges and Opportunities to Personalize Therapy

Despite advances in surgery, radiotherapy, and chemotherapy, glioblastoma (GBM) remains a malignancy with poor prognosis. The molecular profile of GBM is diverse across patients, and individual responses to therapy are highly variable. Yet, patients diagnosed with GBM are treated with a rather uniform paradigm. Exploiting these molecular differences and inter-individual responses to therapy may present an opportunity to improve the otherwise bleak prognosis of patients with GBM. This review aims to examine one group of chemotherapeutics: Topoisomerase 2 (TOP2) poisons, a class of drugs that enables TOP2 to induce DNA damage, but interferes with its ability to repair it. These potent chemotherapeutic agents are currently used for a number of malignancies and have shown promise in the treatment of GBM. Despite their robust efficacy in vitro, some of these agents have fallen short of achieving similar results in clinical trials for this tumor. In this review, we explore reasons for this discrepancy, focusing on drug delivery and individual susceptibility differences as challenges for effective TOP2-targeting for GBM. We critically review the evidence implicating genes in susceptibility to TOP2 poisons and categorize this evidence as experimental, correlative or both. This is important as mere experimental evidence does not necessarily lead to identification of genes that serve as good biomarkers of susceptibility for personalizing the use of these drugs.

Cell-Penetrating Peptide-Modified Gold Nanoparticles for the Delivery of Doxorubicin to Brain Metastatic Breast Cancer

As therapies continue to increase the lifespan of patients with breast cancer, the incidence of brain metastases has steadily increased, affecting a significant number of patients with metastatic disease. However, a major barrier toward treating these lesions is the inability of therapeutics to penetrate into the central nervous system and accumulate within intracranial tumor sites. In this study, we designed a cell-penetrating gold nanoparticle platform to increase drug delivery to brain metastatic breast cancer cells. TAT peptide-modified gold nanoparticles carrying doxorubicin led to improved cytotoxicity toward two brain metastatic breast cancer cell lines with a decrease in the IC50 of at least 80% compared to free drug. Intravenous administration of these particles led to extensive accumulation of particles throughout diffuse intracranial metastatic microsatellites with cleaved caspase-3 activity corresponding to tumor foci. Furthermore, intratumoral administration of these particles improved survival in an intracranial MDA-MB-231-Br xenograft mouse model. Our results demonstrate the promising application of gold nanoparticles for improving drug delivery in the context of brain metastatic breast cancer.

The Role of Chemotherapy in the Treatment of Malignant Astrocytomas

Malignant astrocytomas are aggressive neoplasms with a dismal prognosis despite optimal treatment. Maximal resective surgery is traditionally complemented by radiation therapy. Chemotherapy is now used on patients as initial therapy when their functional status is congruent with further treatment. The classic agents used are nitrosoureas, but temozolomide has taken the front seat recently, with recent data demonstrating increased survival when this agent is used concurrently with radiation therapy in newly diagnosed glioblastoma patients. A new class of agents, refered to as biological modifiers, are increasingly used in clinical trials in an effort to affect the intrinsic biologic aberrations harboured by tumor cells. These drugs comprise differentiation agents, anti-angiogenic agents, matrix-metalloproteinase inhibitors and signal transduction inhibitors, among others. This article reviews the standard cytotoxic agents that have been used to treat malignant astrocytomas, and the different combination regimens offering promise. In addition, recent advances with biological modifiers are also discussed.

Effective high-capacity gutless adenoviral vectors mediate transgene expression in human glioma cells

Glioblastoma multiforme (GBM) is the most common subtype of primary malignant brain tumor. Although serotype 5 adenoviral vectors (Ads) have been used successfully in clinical trials for GBM, the capacity of Ads to infect human glioma cells and the expression of adenoviral receptors in GBM cells have been challenged. In this report, we studied the expression of three molecules that have been shown to mediate adenoviral entry into cells, i.e., coxsackie and adenovirus receptor (CAR), integrin alphavbeta3 (INT), and major histocompatibility complex class I (MHCI), in rodent glioma cell lines and low-passage primary cultures and cell lines from human GBM. We correlated levels of expression of CAR, INT, and MHCI with transduction efficiency elicited by several high-capacity helper-dependent adenoviral vectors (HC-Ads). Expression levels of adenoviral receptors were variable among the different GBM cells studied. HC-Ad-mediated therapeutic gene expression was efficient, ranging between 20 and 80% of the total target cells expressing the encoded transgenes. Our results show no correlation between the levels of CAR, INT, or MHCI molecules and the levels of transgene expression or the number of GBM cells transduced. We conclude that expression levels of adenoviral receptors do not predict their transduction efficiency or biological function.

Therapeutic efficacy of targeting chemotherapy using local hyperthermia and thermosensitive liposome: evaluation of drug distribution in a rat glioma model

A method was developed of targeting chemotherapy using thermosensitive liposomes to treat malignant gliomas. Using the brain heating system, when the tumour core is heated to >43 degrees C, the tumour infiltrating zone is exposed to mild hyperthermia (40-43 degrees C). Thermosensitive liposomes were designed to release their contents at 40 degrees C to target both the tumour core and tumour infiltrating zone. The present study investigated the anti-tumour effect on rat glioma models in tumour drug uptake and tumour growth delay studies. Elevated accumulation of ADR in the rat C6 glioma after treatment was obtained in the area heated to >40 degrees C. However, there was no significant difference between the areas heated to 40-42 degrees C and >43 degrees C. Furthermore, it was found that ADR concentrations in the mildly hyperthermic areas were significantly higher following treatment with liposomal ADR than with free ADR. The animals treated with the new combination therapy had significantly longer overall survival time in comparison to those receiving other treatments. Thus, thermosensitive liposomes release their contents in response to mild hyperthermia and this combination therapy has a greater therapeutic efficacy for malignant brain tumours. This method is a promising approach for the treatment of malignant glioma patients.