Could IGF-I levels play a neuroprotective role in patients with large vestibular schwannomas?

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

A Review of Drug Therapy in Vestibular Schwannoma

Vestibular schwannomas (VSs, also known as acoustic neuromas) are benign intracranial tumors commonly managed with observation, surgery, and radiotherapy. There is currently no approved pharmacotherapy for VS patients, which is why we conducted a detailed search of relevant literature from PubMed and Web of Science to explore recent advances and experiences in drug therapy. VSs feature a long course of disease that requires treatment to have minimal long-term side effects. Conventional chemotherapeutic agents are characterized by neurotoxicity or ototoxicity, poor effect on slow-growing tumors, and may induce new mutations in patients who have lost tumor suppressor function, and therefore are unsuitable for treating VSs. Along with the well-investigated molecular pathophysiology of VS and the increasingly accessible technology such as drug repositioning platform, many molecular targeted inhibitors have been identified and shown certain therapeutic effects in preclinical experiments or clinical trials.

Sevoflurane downregulates insulin-like growth factor-1 to inhibit cell proliferation, invasion and trigger apoptosis in glioma through the PI3K/AKT signaling pathway

Sevoflurane is a new type of inhalation anesthetic used widely in the clinic. It has the characteristics of rapid induction, rapid recovery, and less irritative to the airway. Studies have shown that sevoflurane can affect the invasion and migration of a variety of malignant tumors. However, its effects on human glioma cells and related mechanisms are not clear. Cultured U251 and U87 cells were pretreated with sevoflurane. The effect of sevoflurane on proliferation was evaluated by MTT, and cell migration assay, cell apoptosis, and invasion ability were evaluated by wound-healing assay, cell apoptosis, and Transwell assays. Insulin-like growth factor-1 (IGF-1) and PI3K/AKT signaling pathway gene expression in sevoflurane-treated cell lines was measured by western blotting analysis, respectively. 5% sevoflurane significantly inhibited proliferation ability in both U251 and U87 cells. Sevoflurane inhibited glioma cells invasion and migration, and promoted apoptosis. Sevoflurane inhibited IGF-1 and promoted the expression of apoptosis-related proteins in glioma cells. In addition, sevoflurane inhibited the PI3K/AKT signaling pathway in glioma cells. This study clarifies that sevoflurane inhibits proliferation, invasion, and migration, and promotes apoptosis in glioma cells. These effects are regulated by IGF-1, an upstream gene of the PI3K/AKT signaling pathway. These findings may be significant for the selection of anesthetic agents in glioma surgery to improve the prognosis of patients.