Complications of chemotherapy in neuro-oncology

Sex differences in adverse events in Medicare individuals ≥ 66 years of age post glioblastoma treatment

PURPOSE

Glioblastoma (GB) is the most common primary malignant brain tumor with the highest incidence occurring in older adults with a median age at diagnosis of 64 years old. While treatment often improves survival it brings toxicities and adverse events (AE). Here we identify sex differences in treatment patterns and AE in individuals ≥ 66 years at diagnosis with GB.

METHODS

Using the SEER-Medicare dataset sex differences in adverse events were assessed using multivariable logistic regression performed to calculate the male/female odds ratio (M/F OR) and 95% confidence intervals [95% CI] of experiencing an AE adjusted for demographic variables and Elixhauser comorbidity score.

RESULTS

Males with GB were more likely to receive standard of care (SOC; Surgery with concurrent radio-chemotherapy) [20%] compared to females [17%], whereas females were more likely to receive no treatment [26%] compared to males [21%]. Females with GB receiving SOC were more likely to develop gastrointestinal disorders (M/F OR = 0.76; 95% CI,0.64-0.91, p = 0.002) or blood and lymphatic system disorders (M/F OR = 0.79; 95% CI,0.66-0.95, p = 0.012). Males with GB receiving SOC were more likely to develop cardiac disorders (M/F OR = 1.21; 95% CI,1.02-1.44, p = 0.029) and renal disorders (M/F OR = 1.65; 95% CI,1.37-2.01, p < 0.001).

CONCLUSIONS

Sex differences for individuals, 66 years and older, diagnosed with GB exist in treatment received and adverse events developed across different treatment modalities.

2-Deoxy-D-glucose increases the sensitivity of glioblastoma cells to BCNU through the regulation of glycolysis, ROS and ERS pathways: In vitro and in vivo validation

Chloroethylnitrosoureas (CENUs) exert antitumor activity via producing dG-dC interstrand crosslinks (ICLs). However, tumor resistance make it necessary to find novel strategies to improve the therapeutic effect of CENUs. 2-Deoxy-D-glucose (2-DG) is a well-known glycolytic inhibitor, which can reprogram tumor energy metabolism closely related to tumor resistance. Here, we investigated the chemosensitization effect of 2-DG on l,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) against glioblastoma cells and the underlying mechanisms. We found that 2-DG significantly increased the inhibitory effects of BCNU on tumor cells compared with BCNU alone, while 2-DG showed no obvious enhancing effect on the BCNU-induced cytotoxicity for normal HaCaT and HA1800 cells. Proliferation, migration and invasion determinations presented the same trend as survival on tumor cells. 2-DG plus BCNU increased the energy deficiency through a more effective inhibition of glycolytic pathway. Notably, the combination of 2-DG and BCNU aggravated oxidative stress in glioblastoma cells, along with a significant decrease in glutathione (GSH) levels, and an increase in intracellular reactive oxygen species (ROS). Subsequently, we demonstrated that the combination treatment led to increased apoptosis via activating mitochondria and endoplasmic reticulum stress (ERS) related apoptosis pathways. Finally, we found that the dG-dC level was significantly increased after 2-DG pretreatment compared to BCNU alone by HPLC-ESI-MS/MS analysis. Finally, in vivo, 2-DG plus BCNU significantly suppressed tumor growth with lower side effects compared with BCNU alone in tumor-bearing mice. In summary, we proposed that 2-DG may have potential to increase the sensitivity of glioblastoma cells to BCNU by regulating glycolysis, ROS and ERS pathways in clinical setting.

Self-Assembled Nanomicelles to Enhance Solubility and Anticancer Activity of Etoposide

It is hypothesized that etoposide/VP-16 nanomicellar formulation (VP-16 NMF) utilizing D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) can improve etoposide solubility and anticancer activity. The following four different concentrations of TPGS: 3, 6, 8, and 10 wt% were used to solubilize the drug. Among these four formulations, 10 wt% of TPGS loaded with VP-16 NMF dramatically enhanced etoposide apparent solubility by 26-folds compared with the native drug. The physicochemical properties of the optimized formulation were further analyzed by dynamic light scattering, X-ray powder diffraction, scanning electron microscopy, proton nuclear magnetic resonance (¹HNMR) and Fourier transform infrared spectroscopy. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) was used to assess solubility and intracellular uptake of the drug from the NMF. Cell viability assay ([3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium solution [MTS]) was performed on MCF-7 and MCF-10A cell lines to assess intracellular uptake and anticancer activity of etoposide. The MTS assay results showed that the VP-16 NMF platform provides a higher anticancer activity than the native VP-16 on the MCF-7 cells line as it integrates a dual anticancer activity of VP-16 and TPGS. LC-MS/MS data showed a threefold increase in cellular uptake of VP-16 NMF in MCF-7 cell line compared with the native etoposide. These data suggest that an optimal TPGS concentration can improve VP-16 bioavailability and efficacy with potential benefits for chemotherapy.

PTPRT Could Be a Treatment Predictive and Prognostic Biomarker for Breast Cancer

The role of PTPRT in breast cancer was not comprehensively explored and well analyzed. Our study comprehensively searched available databases to analyze the clinical role of PTPRT in breast cancer. We found PTPRT was an antioncogene and could be used to distinguish different stages, age groups, molecular types, and grades for breast cancer. PTPRT might be primary resistance biomarkers for taxane, anthracycline, and ixabepilone but not be acquired resistance biomarkers. Higher PTPRT expression levels were associated with longer overall survival and recurrence-free survival. PTPRT was negatively associated with Ki67 and CDK4/6 but positively associated with BCL-2. PTPRT might be associated with cell cycle and microtubule, and tumor infiltration in B cell and macrophage cell. PTPRT could predict chemotherapy effectiveness and prognosis for breast cancer patients. PTPRT might inhibit tumor growth via disrupting the microtubule dynamics and cell cycle in breast cancer.

Interstrand Crosslink Repair as a Target for HDAC Inhibition

DNA interstrand crosslinks (ICLs) covalently connect complementary DNA strands. Consequently, DNA replication and transcription are hampered, DNA damage responses (DDR) are initiated, and cell death is triggered. Therefore, drugs inducing ICLs are effective against rapidly growing cancer cells. However, tumors engage a complicated enzymatic machinery to repair and survive ICLs. Several factors, including the post-translational acetylation/deacetylation of lysine residues within proteins, control this network. Histone deacetylases (HDACs) modulate the expression and functions of DNA repair proteins which remove ICLs and control the accessibility of chromatin. Accordingly, histone deacetylase inhibitors (HDACi) are small, pharmacologically and clinically relevant molecules that sensitize cancer cells to ICL inducers. We discuss the mechanism of ICL repair and targets of HDACi within this pathway.

Chloroethylating nitrosoureas in cancer therapy: DNA damage, repair and cell death signaling

Chloroethylating nitrosoureas (CNU), such as lomustine, nimustine, semustine, carmustine and fotemustine are used for the treatment of malignant gliomas, brain metastases of different origin, melanomas and Hodgkin disease. They alkylate the DNA bases and give rise to the formation of monoadducts and subsequently interstrand crosslinks (ICL). ICL are critical cytotoxic DNA lesions that link the DNA strands covalently and block DNA replication and transcription. As a result, S phase progression is inhibited and cells are triggered to undergo apoptosis and necrosis, which both contribute to the effectiveness of CNU-based cancer therapy. However, tumor cells resist chemotherapy through the repair of CNU-induced DNA damage. The suicide enzyme O⁶-methylguanine-DNA methyltransferase (MGMT) removes the precursor DNA lesion O⁶-chloroethylguanine prior to its conversion into ICL. In cells lacking MGMT, the formed ICL evoke complex enzymatic networks to accomplish their removal. Here we discuss the mechanism of ICL repair as a survival strategy of healthy and cancer cells and DNA damage signaling as a mechanism contributing to CNU-induced cell death. We also discuss therapeutic implications and strategies based on sequential and simultaneous treatment with CNU and the methylating drug temozolomide.

Complications from pharmacotherapy

The pharmacotherapy management of cancers of the nervous system has significant overlap with systemic solid cancers that may utilize similar drugs or agents. There is however a unique aspect related to central nervous system (CNS) cancers where therapies directed against a malignant process may have enhanced toxicities or toxicities unique to the CNS. In addition, many agents used to treat CNS malignancies have unique CNS toxicities that may require a specific intervention. This chapter attempts to review conventional and biologic therapies utilized for CNS malignancies and characterize expected and, if known, unique toxicities.

Effects of temozolomide (TMZ) on the expression and interaction of heat shock proteins (HSPs) and DNA repair proteins in human malignant glioma cells

We previously reported the association of HSPA1A and HSPB1 with high-grade astrocytomas, suggesting that these proteins might be involved in disease outcome and response to treatment. With the aim to better understand the resistance/susceptibility processes associated to temozolomide (TMZ) treatment, the current study was performed in three human malignant glioma cell lines by focusing on several levels: (a) apoptotic index and senescence, (b) DNA damage, and (c) interaction of HSPB1 with players of the DNA damage response. Three human glioma cell lines, Gli36, U87, and DBTRG, were treated with TMZ evaluating cell viability and survival, apoptosis, senescence, and comets (comet assay). The expression of HSPA (HSPA1A and HSPA8), HSPB1, O6-methylguanine-DNA methyltransferase (MGMT), MLH1, and MSH2 was determined by immunocytochemistry, immunofluorescence, and Western blot. Immunoprecipitation was used to analyze protein interaction. The cell lines exhibited differences in viability, apoptosis, and senescence after TMZ administration. We then focused on Gli36 cells (relatively unstudied) which showed very low recovery capacity following TMZ treatment, and this was related to high DNA damage levels; however, the cells maintained their viability. In these cells, MGMT, MSH2, HSPA, and HSPB1 levels increased significantly after TMZ administration. In addition, MSH2 and HSPB1 proteins appeared co-localized by confocal microscopy. This co-localization increased after TMZ treatment, and in immunoprecipitation analysis, MSH2 and HSPB1 appeared interacting. In contrast, HSPB1 did not interact with MGMT. We show in glioma cells the biological effects of TMZ and how this drug affects the expression levels of heat shock proteins (HSPs), MGMT, MSH2, and MLH1. In Gli36 cells, the results suggest that interactions between HSPB1 and MSH2, including co-nuclear localization, may be important in determining cell sensitivity to TMZ.