Efficacy Of BCNU Research Articles

Abstract 3838: Inhibition of the spectraplakin protein MACF1 sensitizes glioblastomas to BCNU

Abstract Glioblastoma heterogeneity and diversity is recognized as a major contributing factor to the resistance of these cancers to clinical chemo- and radiotherapy treatment regimens. This diversity is attributed in part to a plethora of novel unevaluated proteins whose functions participate in glioblastoma etiology, progression, and recurrence. One such protein is the cytoskeletal cross-linker, Microtubule Actin Crosslinking Factor 1 (MACF1), which we have previously shown was expressed at high levels in glioblastoma tissue as compared to its absence in normal brain tissue. In support of these findings immunoblotting expression analysis in this study showed that MACF1 protein expression was upregulated in response to BCNU exposure in glioblastoma cells. Subsequently, experiments were conducted to assess the combinatorial effect of MACF1 inhibition in conjunction with BCNU treatment. A CRISPR-Cas9 genome editing approach was used to inhibit MACF1 function prior to drug exposure. Cell proliferation analysis revealed a cooperative synergistic effect of MACF1 inhibition and BCNU treatment on the reduction of glioblastoma cells as compared to cells treated with either BCNU or CRISPR inhibition of MACF1 alone. In conclusion, upregulation of MACF1 in response to BCNU suggests that this spectraplakin protein may play a role in the mechanistic resistance of glioblastomas to BCNU and the therapeutic prognosis of glioblastomas treated with this drug. Additionally, this study demonstrated that MACF1 inhibition is a novel neoadjuvant approach that enhances the therapeutic efficacy of BCNU. Citation Format: Danielle Borlay, Kala Bonner, Orica Kutten, Katelyn Atkinson, Quincy A. Quick. Inhibition of the spectraplakin protein MACF1 sensitizes glioblastomas to BCNU [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3838.

Carmustine (BCNU) plus Teniposide (VM26) in Recurrent Malignant Glioma

Background: After the failure of radiotherapy and temozolomide, there is no established standard therapy for patients with recurrent glioblastoma (GBM). Based on the promising data of a previous trial (NOA-01) for primary GBM and some retrospective case series for GBM recurrence, the combination of nimustine and teniposide (VM26) was commonly used in this setting. When nimustine was no longer available in Europe, we switched to intrvaveneous carmustine (BCNU). Data on the toxicity and efficacy of BCNU and VM26 in recurrent GBM are lacking. Methods: In our neurooncological center, all patients with recurrent GBM or with progressed glioma and a typical MRI lesion suggesting GBM treated with BCNU (130-150 mg/m², day 1/42) and VM26 (45-60 mg/m², days 1-3/42) were analyzed retrospectively for progression-free survival, overall survival and toxicity. Results: Fifteen patients (median age 52 years) were identified. Median progression-free survival was 2 months and median overall survival was 4 months. Two patients (14%) developed grade 3/4 hematotoxicity. Nonhematological toxicity ≥grade 3 was not observed. Conclusion: Our data do not support the application of BCNU/VM26 in patients with late stages of recurrent GBM.

Improving thermal stability and efficacy of BCNU in treating glioma cells using PAA-functionalized graphene oxide

Background1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), a commercial chemotherapeutic drug for treating malignant brain tumors, has poor thermal stability and a short half-life. Immobilization of BCNU on a nanocarrier might increase the thermal stability of BCNU and extend its half-life.MethodsNanosized graphene oxide (GO) could be modified by polyacrylic acid (PAA) to improve the aqueous solubility and increase the cell penetration efficacy of the nanocarrier. PAA–GO intended as a drug carrier for BCNU was prepared and characterized in this study. The size and thickness of PAA–GO was investigated by transmission electron microscopy and atomic force microscopy, and the presence of PAA functional groups was confirmed by electron spectroscopy for chemical analysis and thermogravimetric analysis. BCNU was conjugated to PAA–GO by covalent binding for specific killing of cancer cells, which could also enhance the thermal stability of the drug.ResultsSingle layer PAA–GO (about 1.9 nm) with a lateral width as small as 36 nm was successfully prepared. The optimum drug immobilization condition was by reacting 0.5 mg PAA–GO with 0.4 mg BCNU, and the drug-loading capacity and residual drug activity were 198 μg BCNU/mg PAA–GO and 70%, respectively. This nanocarrier significantly prolonged the half-life of bound BCNU from 19 to 43 hours compared with free drug and showed efficient intracellular uptake by GL261 cancer cells. The in vitro anticancer efficacy of PAA–GO–BCNU was demonstrated by a 30% increase in DNA interstrand cross-linking and a 77% decrease in the IC50 value toward GL261 compared with the same dosage of free drug.ConclusionNanosized PAA–GO serves as an efficient BCNU nanocarrier by covalent binding. This nanocarrier will be a promising new vehicle for an advanced drug delivery system in cancer therapy.

Efficacy of BCNU and paclitaxel loaded subcutaneous implants in the interstitial chemotherapy of U-87 MG human glioblastoma xenografts

Nude mice were challenged with human U-87 MG glioblastoma tumors to assess the efficacy of different cytostatics and different application protocols. While the intraperitoneal application of BCNU solutions (3 times 20 mg BCNU/kg) had no effect on tumor growth, the application of polymer matrices made of a physical mixture of poly(1,3-bis[carboxyphenoxpropane]-co-sebacic acid) 20:80 with poly( d, l-lactic-co-glycolic acid) loaded with 0.25 mg BCNU, slowed down the growth of tumors significantly. When the animals were treated with implants carrying 0.25 mg BCNU they responded to the treatment whether the tumor had been inoculated recently (9 days ago) or whether it was fully established (after 20 days). After its sensitivity was proven, the xenograft model was used to further investigate the efficacy of anticancer drugs and some treatment regimens using polymer implants. Thus the tumor model allowed to discriminate between the efficacy of different doses of BCNU. Only implants loaded with 0.75 or 1 mg of BCNU led to a substantial suppression of tumor growth over approximately 2 months. While BCNU was only able to suppress the growth of the tumor, the combination of BCNU with paclitaxel led to a complete remission in some animals. These preliminary results suggest that combinations of cytostatics might improve local chemotherapy of malignant glioma substantially. Based on our data it will be worthwhile to investigate implants that release drugs such as BCNU and paclitaxel closer. Amongst other factors we will try to elucidate the effect of repetitive doses of drugs using programmable implants.

Eradication of a disseminated mouse lymphoma by 1,3‐BIS(2‐chloroethyl)‐1‐nitrosourea is immunologically mediated and accompanied by de novo generation of anti‐tumor cytotoxicity

The anti-tumor effect of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) was examined in BALB/c mice bearing increasing burdens of a syngeneic lymphoma (YC8). A single i.p. injection of the drug resulted in over 75% of cures when given at day 3, 5, 7 or 10 after an i.v. inoculum of 10(4) YC8 cells. The efficacy of BCNU on mice bearing large tumor burdens (from day 5 on) was not only due to its tumoricidal activity, but was immunologically mediated. Residual tumorigenic cells could be recovered in the livers of 5-day tumor bearers (TB) up to 2 weeks after BCNU treatment and only a low percentage of cures could be achieved when BCNU was administered to nude mice. In addition, BCNU-cured mice specifically rejected a lethal YC8 challenge and their splenocytes developed anti-tumor cytotoxicity in response to in vitro stimulation with YC8 cells. During kinetic experiments a 2-week period elapsed after BCNU injection before an anti-tumor cytotoxic T-lymphocyte (CTL) response could be generated by spleen cells of BCNU-treated 5-day TB. This period was characterized by immunosuppression as evaluated from impairment in the generation of lymphokine-activated killer (LAK) cells or of allospecific primary CTL responses by spleen cells from BCNU-treated 5-day TB and BCNU-treated normal mice. LAK cells first recovered and could be generated 7 days later, whereas primary allospecific CTL responses could only be detected by day 14, concomitantly with the generation of anti-tumor cytotoxicity by 5-day TB. The development of secondary in vitro CTL responses, however, was permanently abrogated. Spleen cells from BALB/c mice immunized either with YC8 or with DBA/2 minor histocompatibility antigens and treated with BCNU 1 week after the last immunization failed to mount an in vitro CTL response to their immunizing antigen, even when the cultures were supplemented with recombinant interleukin-2.

Polychemotherapy with 5-(3,3 dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC; NSC-45388), 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU, NSC-409962) and vincristine (NSC-67574) in the metastatic phase of melanoma

The toxic and therapeutic effects obtained with a triple drug combination (BCNU, DTIC and VCR) administered in a cyclic fashion to 41 unselected evaluable patients with metastatic malignant melanoma are reported. Side effects were moderate and reversible. The overall regression rate was 44% without difference between males and females. Partial remission (> 50%) plus complete remission was 19.5% with an average duration of 5.1 months (1–20+). With the exclusion of bone lesions, all types of metastases showed regression especially those located in the soft tissues (lymph nodes and skin). The actuarial analysis of survival shows that responders live twice as long as non responders (median survival 12 months versus 6 months). However, the superior therapeutic efficacy of BCNU + DTIC + VCR over DTIC alone in metastatic melanoma remains to be demonstrated. A controlled study with different triple combinations is now in progress.