Convection-enhanced delivery of sulfasalazine prolongs survival in a glioma stem cell brain tumor model

Identification of the ultrahigh-risk subgroup in neuroblastoma cases through DNA methylation analysis and its treatment exploiting cancer metabolism

Neuroblastomas require novel therapies that are based on the exploitation of their biological mechanism. To address this need, we analyzed the DNA methylation and expression datasets of neuroblastomas, extracted a candidate gene characterizing the aggressive features, and conducted functional studies. Based on the DNA methylation data, we identified a subgroup of neuroblastoma cases with 11q loss of heterozygosity with extremely poor prognosis. PHGDH, a serine metabolism-related gene, was extracted as a candidate with strong expression and characteristic methylation in this subgroup as well as in cases with MYCN amplification. PHGDH inhibition suppressed neuroblastoma cell proliferation in vitro and in vivo, indicating that the inhibition of serine metabolism by PHGDH inhibitors is a therapeutic alternative for neuroblastoma. Inhibiting the arginine metabolism, which is closely related to serine metabolism using arginine deiminase, had a combination effect both in vitro and in vivo, especially on extracellular arginine-dependent neuroblastoma cells with ASS1 deficiency. Expression and metabolome analyses of post-dose cells confirmed the synergistic effects of treatments targeting serine and arginine indicated that xCT inhibitors that inhibit cystine uptake could be candidates for further combinatorial treatment. Our results highlight the rational therapeutic strategy of targeting serine/arginine metabolism for intractable neuroblastoma.

Ferroptosis in glioma treatment: Current situation, prospects and drug applications

Ferroptosis is a regulatory form of iron-dependent cell death caused by the accumulation of lipid-based reactive oxygen species (ROS) and differs from apoptosis, pyroptosis, and necrosis. Especially in neoplastic diseases, the susceptibility of tumor cells to ferroptosis affects prognosis and is associated with complex effects. Gliomas are the most common primary intracranial tumors, accounting for disease in 81% of patients with malignant brain tumors. An increasing number of studies have revealed the particular characteristics of iron metabolism in glioma cells. Therefore, agents that target a wide range of molecules involved in ferroptosis may regulate this process and enhance glioma treatment. Here, we review the underlying mechanisms of ferroptosis and summarize the potential therapeutic options for targeting ferroptosis in glioma.

The influence of the blood-brain barrier in the treatment of brain tumours

Brain tumours have a poor prognosis and lack effective treatments. The blood-brain barrier (BBB) represents a major hurdle to drug delivery to brain tumours. In some locations in the tumour, the BBB may be disrupted to form the blood-brain tumour barrier (BBTB). This leaky BBTB enables diagnosis of brain tumours by contrast enhanced magnetic resonance imaging; however, this disruption is heterogeneous throughout the tumour. Thus, relying on the disrupted BBTB for achieving effective drug concentrations in brain tumours has met with little clinical success. Because of this, it would be beneficial to design drugs and drug delivery strategies to overcome the 'normal' BBB to effectively treat the brain tumours. In this review, we discuss the role of BBB/BBTB in brain tumour diagnosis and treatment highlighting the heterogeneity of the BBTB. We also discuss various strategies to improve drug delivery across the BBB/BBTB to treat both primary and metastatic brain tumours. Recognizing that the BBB represents a critical determinant of drug efficacy in central nervous system tumours will allow a more rapid translation from basic science to clinical application. A more complete understanding of the factors, such as BBB-limited drug delivery, that have hindered progress in treating both primary and metastatic brain tumours, is necessary to develop more effective therapies.

Correlation between amino acid metabolism and self-renewal of cancer stem cells: Perspectives in cancer therapy

Cancer stem cells (CSCs) possess self-renewal and differentiation potential, which may be related to recurrence, metastasis, and radiochemotherapy resistance during tumor treatment. Understanding the mechanisms via which CSCs maintain self-renewal may reveal new therapeutic targets for attenuating CSC resistance and extending patient life-span. Recent studies have shown that amino acid metabolism plays an important role in maintaining the self-renewal of CSCs and is involved in regulating their tumorigenicity characteristics. This review summarizes the relationship between CSCs and amino acid metabolism, and discusses the possible mechanisms by which amino acid metabolism regulates CSC characteristics particularly self-renewal, survival and stemness. The ultimate goal is to identify new targets and research directions for elimination of CSCs.

LncRNA CCAT2 promotes angiogenesis in glioma through activation of VEGFA signalling by sponging miR-424

Glioma is characterized by high morbidity, high mortality and poor prognosis. Recent studies exhibited that lncRNA CCAT2 is overexpressed in glioma and promotes glioma progression, but the specific molecular biological mechanism remains to be determined. We performed qRT-PCR to evaluate the expression of related genes, Western blotting analysis to measure protein levels, colony formation assay to detect the proliferative ability of glioma cells, flow cytometry to measure cell apoptosis, bioinformatics analysis and dual luciferase assay to verify the binding sites and the targeted regulatory relationship in A172 and U251 cell lines and tube formation assay to determine endothelial angiogenesis. LncRNA CCAT2 and VEGFA were highly expressed, while miR-424 was expressed at low levels in NHA cells. Furthermore, knockdown of lncRNA CCAT2 decreased cell proliferation, increased cell apoptosis and inhibited endothelial angiogenesis in glioma. Moreover, lncRNA CCAT2 shared a complementary sequence with miR-424 which in turn directly bound to the 3'-UTR of VEGFA. Further investigation indicated that lncRNA CCAT2 promoted cell proliferation and endothelial angiogenesis by inducing the PI3K/AKT signalling pathway in glioma. The oncogenic lncRNA CCAT2 is highly associated with the development of glioma and exerts its function by upregulating VEGFA via miR-424.

Sulfasalazine could modulate the CD44v9-xCT system and enhance cisplatin-induced cytotoxic effects in metastatic bladder cancer

The prognostic role of CD44v9, a variant isoform of CD44 and a new cell surface marker of cancer stem cells, remains unclear in bladder cancer (BC) patients. Furthermore, limited information is available on the functional role of sulfasalazine (SSZ), which could modulate the CD44v9‐xCT system in order to enhance cisplatin (CDDP)‐induced cytotoxicity and inhibit the metastatic potential of BC. CD44v9 protein expression was examined immunohistochemically in 63 muscle invasive BC (MIBC) patients who underwent radical cystectomy. CD44v9 expression was independently associated with disease recurrence and cancer‐specific death in MIBC. Cytotoxic effects, glutathione levels, and reactive oxygen species production by SSZ and CD44v9 and phospho‐p38^MAPK protein expression by SSZ with or without CDDP were assessed in MBT‐2V cells with highly metastatic potential. Sulfasalazine exerted cytotoxic effects against MBT‐2V cells by inhibiting glutathione levels and inducing the production of reactive oxygen species. Sulfasalazine in combination with CDDP appeared to exert strong cytotoxic effects against MBT‐2V cells by inhibiting CD44v9 expression and upregulating phospho‐p38^MAPK expression. The inhibitory effects of SSZ with or without CDDP were also investigated using an MBT‐2V lung metastatic model. In the murine lung metastatic BC model, SSZ significantly prolonged animal survival. Furthermore, the combination of SSZ with CDDP exerted stronger inhibitory effects on the establishment of lung tumor nodules than SSZ or CDDP alone. CD44v9 expression could be a clinical biomarker for predicting poor outcomes in MIBC patients. Sulfasalazine in combination with CDDP has potential as a novel therapy against metastatic BC.

Convection-Enhanced Delivery in the Treatment of Glioblastoma

OBJECTIVE

To describe the indications for convection-enhanced delivery in the treatment of glioblastoma, highlighting candidates for the delivery method, mechanics of drug delivery, and management of acute and long-term complications.

DATA SOURCES

A conceptual framework drawn from published literature as well as author's expert experiences.

CONCLUSION

Convection-enhanced delivery is an established method of delivering new therapies to patients with glioblastoma. Management of both acute and long-term complications is often drug dependent.

IMPLICATIONS FOR NURSING PRACTICE

Nurses should be able to recognize and manage potential complications during the infusion of agents delivered via convection-enhanced delivery. Post-infusion symptoms may worsen because of immunologic responses related to the drug and management should be directed toward symptom relief and support without interference on the immunologic response.

The role of inflammation in subventricular zone cancer

The adult subventricular zone (SVZ) stem cell niche has proven vital for discovering neurodevelopmental mechanisms and holds great potential in medicine for neurodegenerative diseases. Yet the SVZ holds a dark side - it can become tumorigenic. Glioblastomas can arise from the SVZ via cancer stem cells (CSCs). Glioblastoma and other brain cancers often have dismal prognoses since they are resistant to treatment. In this review we argue that the SVZ is susceptible to cancer because it contains stem cells, migratory progenitors and unusual inflammation. Theoretically, SVZ stem cells can convert to CSCs more readily than can postmitotic neural cells. Additionally, the robust long-distance migration of SVZ progenitors can be subverted upon tumorigenesis to an infiltrative phenotype. There is evidence that the SVZ, even in health, exhibits chronic low-grade cellular and molecular inflammation. Its inflammatory response to brain injuries and disease differs from that of other brain regions. We hypothesize that the SVZ inflammatory environment can predispose cells to novel mutations and exacerbate cancer phenotypes. This can be studied in animal models in which human mutations related to cancer are knocked into the SVZ to induce tumorigenesis and the CSC immune interactions that precede full-blown cancer. Importantly inflammation can be pharmacologically modulated providing an avenue to brain cancer management and treatment. The SVZ is accessible by virtue of its location surrounding the lateral ventricles and CSCs in the SVZ can be targeted with a variety of pharmacotherapies. Thus, the SVZ can yield aggressive tumors but can be targeted via several strategies.