Etoposide- and BMY-40481-induced sensory neuropathy in mice

Motor and sensory impairment in survivors of childhood central nervous system (CNS) tumors in the St. Jude Lifetime Cohort (SJLIFE)

BACKGROUND

Survivors of childhood central nervous system (CNS) tumors can develop motor and sensory impairment from their cancer and treatment history. We estimated the prevalence of motor and sensory impairment in survivors compared with controls through clinical assessment and identified associated treatment exposures and functional, quality of life (QOL), and social outcomes.

METHODS

Survivors of childhood CNS tumors from the St. Jude Lifetime Cohort (n = 378, median [range] age 24.0 [18.0-53.0] years, 43.4% female) ≥5 years from diagnosis and controls (n = 445, median [range] age 34.0 [18.0-70.0] years, 55.7% female) completed in-person evaluation for motor and sensory impairment using the modified Total Neuropathy Score. Impairment was graded by modified Common Terminology Criteria for Adverse Events. Multivariable models estimated associations between grade ≥2 motor/sensory impairment, individual/treatment characteristics, and secondary outcomes (function by Physical Performance Test, fitness by physiologic cost index, QOL by Medical Outcomes Survey Short Form-36 physical/mental summary scores, social attainment).

RESULTS

Grade ≥2 motor or sensory impairment was more prevalent in survivors (24.1%, 95% Confidence Interval [CI] 19.8%-29.4%) than controls (2.9%, CI 1.4-4.5%). Among survivors, in multivariable models, motor impairment was associated with vinca exposure <15 mg/m2 versus none (OR 4.38, CI 1.06-18.08) and etoposide exposure >2036 mg/m2 versus none (OR 12.61, CI 2.19-72.72). Sensory impairment was associated with older age at diagnosis (OR 1.09, CI 1.01-1.16) and craniospinal irradiation versus none (OR 4.39, CI 1.68-11.50). There were lower odds of motor/sensory impairment in survivors treated in the year 2000 or later versus before 1990 (Motor: OR 0.29, CI 0.10-0.84, Sensory: OR 0.35, CI 0.13-0.96). Motor impairment was associated with impaired physical QOL (OR 2.64, CI 1.22-5.72).

CONCLUSIONS

In survivors of childhood CNS tumors, motor and sensory impairment is prevalent by clinical assessment, especially after exposure to etoposide, vinca, or craniospinal radiation. Treating motor impairment may improve survivors' QOL.

The protective effect of taurine, piracetam and vinpocetine on etoposide-induced inflammation and brain injury in the serum of female albino rats

Etoposide (ETP) is one of the leading antitumour agents in cancer chemotherapy. Many studies have reported on ETP-induced peripheral neuropathy; however, few reports have focused on its brain toxicity. The current research investigates the protective potential of taurine, piracetam and vinpocetine on serum biomarkers associated with inflammation and brain injury induced by ETP in a rodent model. A total of 30 female albino rats were equally divided into five groups; the 1^st and 2^nd groups were the control and ETP-treated groups, respectively, while the 3^rd, 4^th and 5^th groups were ETP-treated rats cotreated with taurine, piracetam and vinpocetine, respectively. Administration of ETP reduced body weight significantly, enhanced production of serum proinflammatory cytokines including tumour necrosis factor-alpha, interleukin-1 beta (IL-1β) and IL-6 and decreased glutathione serum levels. Moreover, ETP treatment resulted in upregulation of glial fibrillary acidic protein expression and histopathological alterations in the rats' brain compared to the control group. Co-treatment with taurine, piracetam and vinpocetine counteracted ETP-induced brain injury and altered serum biomarkers levels. We concluded that co-treatment with vinpocetine could serve as a complementary therapeutic agent in reducing brain injury and toxicity induced by ETP.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Podophyllotoxin Exposure Affects Organelle Distribution and Functions in Mouse Oocyte Meiosis

Podophyllotoxin (POD) is one of the most characterized lignans that is commonly found in podophyllum, and its preparations and derivatives are widely used in clinical treatment due to strong antitumor and antivirus activities. POD has been reported for its neurotoxicity, liver toxicity, and potential reproductive toxicity. In the present study, we investigated the effects of POD on the organelles of mouse oocytes during meiosis. Our results showed that exposure to POD significantly reduced the developmental competence of mouse oocytes. Further analysis revealed that the endoplasmic reticulum (ER) failed to accumulate to the spindle periphery, suggesting that POD exposure might affect protein synthesis during oocyte meiotic maturation. Similarly, abnormal Golgi apparatus distribution was found after POD exposure, which could be confirmed by the aberrant localization of Rab11a-related vesicles, indicating that POD induced vesicle-based protein transport disorder. We also found the aberrant accumulation of lysosomes in the cytoplasm of POD-exposed oocytes, which implied that POD might lead to aberrant protein degradation. Moreover, the perinuclear distribution of mitochondria was also significantly disturbed, indicating the mitochondrial dysfunction after POD exposure. In all, our study illustrated that exposure to POD might disrupt protein synthesis, transport, degradation, and ATP production by its effects on the distribution and functions of organelles during mouse oocyte meiotic maturation.

Short-term recovery of chemotherapy-induced peripheral neuropathy after treatment for pediatric non-CNS cancer

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent side effect of pediatric cancer treatment. The presentation of CIPN, trajectory and completeness of recovery over the first 6 months postchemotherapy, and the influence of patient and treatment characteristics on recovery are described.

PATIENTS AND METHODS

Sixty-seven children and adolescents treated for non-CNS cancers were evaluated for CIPN using the pediatric modified total neuropathy score (ped-mTNS) while on treatment and 3 and 6 months postchemotherapy. Differences between diagnostic groups and treatment type were evaluated as well as change in scores over time. Risk factors for on-treatment and persistent CIPN at 6 months were identified.

RESULTS

Overall, ped-mTNSs were in the abnormal range for 86.5% during treatment and scores decreased over time (initial 9.3 ± 0.6, 6 months 4.3 ± 0.4; F = 38.14, P < 0.001). By 6 months posttreatment, mean scores and percentage of children with abnormal scores were reduced to 2.4 ± 0.3 and 11.5%, respectively, in the ALL group, but remained higher at 5.7 ± 0.7 and 57%, respectively, for lymphoma, and 5.2 ± 1.0 and 60%, respectively, for other solid tumors. At 6 months posttreatment, light touch deficits and foot strength deficits remained in 19.4 and 59.7%, respectively, compared with only 4.9 and 9.8% of the control population. Subjects who were older at exposure, female, or who received etoposide in addition to vincristine were at higher risk for on-treatment CIPN. On-treatment sensory abnormalities were associated with increased risk of persistent CIPN.

CONCLUSION

While CIPN improves in most pediatric patients, significant numbers, especially those treated for lymphoma or other solid tumors, have remaining neuropathic signs and symptoms 6 months posttreatment.

Multiplexing spheroid volume, resazurin and acid phosphatase viability assays for high-throughput screening of tumour spheroids and stem cell neurospheres

Three-dimensional cell culture has many advantages over monolayer cultures, and spheroids have been hailed as the best current representation of small avascular tumours in vitro. However their adoption in regular screening programs has been hindered by uneven culture growth, poor reproducibility and lack of high-throughput analysis methods for 3D. The objective of this study was to develop a method for a quick and reliable anticancer drug screen in 3D for tumour and human foetal brain tissue in order to investigate drug effectiveness and selective cytotoxic effects. Commercially available ultra-low attachment 96-well round-bottom plates were employed to culture spheroids in a rapid, reproducible manner amenable to automation. A set of three mechanistically different methods for spheroid health assessment (Spheroid volume, metabolic activity and acid phosphatase enzyme activity) were validated against cell numbers in healthy and drug-treated spheroids. An automated open-source ImageJ macro was developed to enable high-throughput volume measurements. Although spheroid volume determination was superior to the other assays, multiplexing it with resazurin reduction and phosphatase activity produced a richer picture of spheroid condition. The ability to distinguish between effects on malignant and the proliferating component of normal brain was tested using etoposide on UW228-3 medulloblastoma cell line and human neural stem cells. At levels below 10 µM etoposide exhibited higher toxicity towards proliferating stem cells, whereas at concentrations above 10 µM the tumour spheroids were affected to a greater extent. The high-throughput assay procedures use ready-made plates, open-source software and are compatible with standard plate readers, therefore offering high predictive power with substantial savings in time and money.

An antimicrotubule agent, TZT-1027, does not induce neuropathologic alterations which are detected after administration of vincristine or paclitaxel in animal models

One of the major dose-limiting toxicities induced by antimicrotubule antitumor agents such as vinca alkaloids and taxanes is peripheral neuropathy. The neurotoxicity of TZT-1027 (a dolastatin 10 derivative antimicrotubule agent) was thus assessed using the animal models for antimicrotubule agent-induced neurotoxicity. Rabbits were intravenously given TZT-1027 or vincristine weekly for 5 weeks. In the mouse study, TZT-1027, vincristine or paclitaxel was intravenously given every 2 days and/or weekly. Despite the neuropathologic evidence such as myelinated axonal and fiber degeneration in the peripheral nerves and in the sensory tracts of the spinal cord following the treatment with vincristine or paclitaxel, no drug-induced alteration was observed in the TZT-1027 groups. Although there are reports that some other dolastatin derivatives with antimicrotubule activity showed no neurotoxic potential in humans, the present study represents the first demonstration in experimental animals that a dolastatin derivative has no, or at least a lower, neurotoxic potential compared to other antimicrotubule agents.