Identification of small molecules that mitigate vincristine‐induced neurotoxicity while sensitizing leukemia cells to vincristine

Vincristine (VCR) is one of the most widely prescribed medications for treating solid tumors and acute lymphoblastic leukemia (ALL) in children and adults. However, its major dose‐limiting toxicity is peripheral neuropathy that can disrupt curative therapy. Peripheral neuropathy can also persist into adulthood, compromising quality of life of childhood cancer survivors. Reducing VCR‐induced neurotoxicity without compromising its anticancer effects would be ideal. Here, we show that low expression of NHP2L1 is associated with increased sensitivity of primary leukemia cells to VCR, and that concomitant administration of VCR with inhibitors of NHP2L1 increases VCR cytotoxicity in leukemia cells, prolongs survival of ALL xenograft mice, but decreases VCR effects on human‐induced pluripotent stem cell‐derived neurons and mitigates neurotoxicity in mice. These findings offer a strategy for increasing VCR’s antileukemic effects while reducing peripheral neuropathy in patients treated with this widely prescribed medication.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Vincristine (VCR) is a widely prescribed drug, but its use is limited by its main side effect, neurotoxicity. There are currently no strategies to mitigate VCR neurotoxicity without altering its antileukemic effects.

• WHAT QUESTION DID THIS STUDY ADDRESS?

How to improve VCR efficacy while reducing its main side effect, neurotoxicity?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

The present study shows for the first time the possibility of reduced VCR ‐induced neurotoxicity while improving VCR anti‐leukemia effect by using small molecules.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

The current translational study could permit a safer and more efficient use of VCR.     

The effect of noise and lipid signals on determination of Gaussian and non‐Gaussian diffusion parameters in skeletal muscle

This work characterizes the effect of lipid and noise signals on muscle diffusion parameter estimation in several conventional and non‐Gaussian models, the ultimate objectives being to characterize popular fat suppression approaches for human muscle diffusion studies, to provide simulations to inform experimental work and to report normative non‐Gaussian parameter values. The models investigated in this work were the Gaussian monoexponential and intravoxel incoherent motion (IVIM) models, and the non‐Gaussian kurtosis and stretched exponential models. These were evaluated via simulations, and in vitro and in vivo experiments. Simulations were performed using literature input values, modeling fat contamination as an additive baseline to data, whereas phantom studies used a phantom containing aliphatic and olefinic fats and muscle‐like gel. Human imaging was performed in the hamstring muscles of 10 volunteers. Diffusion‐weighted imaging was applied with spectral attenuated inversion recovery (SPAIR), slice‐select gradient reversal and water‐specific excitation fat suppression, alone and in combination. Measurement bias (accuracy) and dispersion (precision) were evaluated, together with intra‐ and inter‐scan repeatability. Simulations indicated that noise in magnitude images resulted in <6% bias in diffusion coefficients and non‐Gaussian parameters (α, K), whereas baseline fitting minimized fat bias for all models, except IVIM. In vivo, popular SPAIR fat suppression proved inadequate for accurate parameter estimation, producing non‐physiological parameter estimates without baseline fitting and large biases when it was used. Combining all three fat suppression techniques and fitting data with a baseline offset gave the best results of all the methods studied for both Gaussian diffusion and, overall, for non‐Gaussian diffusion. It produced consistent parameter estimates for all models, except IVIM, and highlighted non‐Gaussian behavior perpendicular to muscle fibers (α ~ 0.95, K ~ 3.1). These results show that effective fat suppression is crucial for accurate measurement of non‐Gaussian diffusion parameters, and will be an essential component of quantitative studies of human muscle quality.     

A Case–Control Study of Lung Cancer Nested in a Cohort of European Asphalt Workers

Background

We conducted a nested case–control study in a cohort of European asphalt workers in which an increase in lung cancer risk has been reported among workers exposed to airborne bitumen fume, although potential bias and confounding were not fully addressed.

Objective

We investigated the contribution of exposure to bitumen, other occupational agents, and tobacco smoking to the risk of lung cancer among asphalt workers.

Methods

Cases were cohort members in Denmark, Finland, France, Germany, the Netherlands, Norway, and Israel who had died of lung cancer between 1980 and the end of follow-up (2002–2005). Controls were individually matched in a 3:1 ratio to cases on year of birth and country. We derived exposure estimates for bitumen fume and condensate, organic vapor, and polycyclic aromatic hydrocarbons, as well as for asbestos, crystalline silica, diesel motor exhaust, and coal tar. Odds ratios (ORs) were calculated for ever-exposure, duration, average exposure, and cumulative exposure after adjusting for tobacco smoking and exposure to coal tar.

Results

A total of 433 cases and 1,253 controls were included in the analysis. The OR was 1.12 [95% confidence interval (CI), 0.84–1.49] for inhalation exposure to bitumen fume and 1.17 (95% CI, 0.88–1.56) for dermal exposure to bitumen condensate. No significant trend was observed between lung cancer risk and duration, average exposure, or cumulative exposure to bitumen fume or condensate.

Conclusions

We found no consistent evidence of an association between indicators of either inhalation or dermal exposure to bitumen and lung cancer risk. A sizable proportion of the excess mortality from lung cancer relative to the general population observed in the earlier cohort phase is likely attributable to high tobacco consumption and possibly to coal tar exposure, whereas other occupational agents do not appear to play an important role.     

Heterogeneity in the effect of albumin and other resuscitation fluids on intracellular oxygen free radical production

BACKGROUND: We hypothesized that by studying a suspension of a single cell type in various resuscitation fluids, we could compare their effects on parameters associated with cell death. METHODS: Jurkat cells were suspended in resuscitation fluids. Using flow cytometry, light scatter, phosphatidylserine translocation, propidium iodide uptake, and intracellular H2O2 production were measured. RESULTS: Buffer (pH, 7.4) and albumin added to Ringer's lactate inhibited the adverse changes, including intracellular oxygen free radical production. Oxygen free radical production was variable within the cell population and inhibited by albumin but not other colloids or crystalloids. This correlated well with the ability of albumin to enhance metabolic activity. A flavoprotein inhibitor blocked H2O2 production, suggesting that mitochondria are the source of the H2O2 and the variability. CONCLUSION: Oxygen free radical inhibition by albumin could explain both its beneficial and its harmful effects.     

Whole body FDG-PET for the evaluation and staging of small cell lung cancer: a preliminary study

PURPOSE: We conducted a randomized trial to investigate whether systematic nodal dissection (SND) is superior to mediastinal lymph nodal sampling (MLS) in surgical treatment of non-small cell lung cancer (NSCLC). METHODS: The patients resectable clinical Stage I-IIIA NSCLC were randomly assigned to lung resection combined with SND or lung resection combined with MLS. After postoperative pathological re-staging, eligible cases were followed up until 30 November 2000. The Kaplan-Meier method was used for survival analysis. COX proportional hazards model was used for prognostic analysis. RESULTS: Of the 532 patients who were enrolled in the study, 268 patients were assigned to lung resection combined with SND and 264 were assigned to lung resection combined with MLS. After surgical restaging only 471 cases were eligible for follow-up. The median survival was 59 months in the group given SND and 34 months in the group given MLS (P=0.0000 by the log rank test). There was significant difference in survival in Stage I (5-year survival 82.16 vs. 57.49%) and Stage IIIA (26.98 vs. 6.18%) by the log rank test and Breslow test. There was no significant yet marginal difference in survival by log rank test (10-year survival 32.04 vs. 26.92%, P=0.0523) but significant difference in survival by Breslow test (5-year survival 50.42 vs. 34.05%, P=0.0284) in Stage II. Types of mediastinal lymph node dissection, pTNM stage, tumor size and number of lymph node metastasis were four factors that influenced long-term survival rate by multivariate analysis. CONCLUSIONS: As compared with MLS, lobectomy (pneumonectomy) combined with SND can improve survival in resectable NSCLC.     

Induction of epidermal hyperplasia,hyperkeratosis, and papillomas in transgenic mice by a targeted v-Ha-ras oncogene

The regulatory elements of the human keratin K1 gene have been used to target expression of the v-Ha-ras oncogene exclusively in the epidermis of transgenic mice. We developed 12 transgenic mouse lines that express the HK1. ras transgene, producing epidermal hyperplasia in neonates and hyperkeratosis in juveniles. Eventually this skin phenotype diminished but with time adult animals developed papillomas that could persist or regress. The rate and frequency of tumorigenesis appeared to be limited, which suggests that v-Ha-ras requires a second or even third event to elicit and maintain a benign phenotype in transgenic mice. Since in certain transgenic lines papillomas appeared at wound sites, it appears that the promotion stimulus from wounding may be a second event. We envision that such transgenic mice that express v-Ha-ras in the epidermis will become a powerful model for assessing how environmental and molecular factors affect the process of multistage skin carcinogenesis in vivo, as well as a model for evaluating novel therapeutic protocols.     

Biochemical studies on pulmonary response to inhalation of methylene chloride

Biochemical response to the toxic lung damage induced by inhalation of methylene chloride was studied. Significant increases in protein, hexose, sialic acid, lactate dehydrogenase, acid and alkaline phosphatase content were observed in the cell-free lavage effluents from lungs of exposed rats compared to the control animals. This was interpreted as increased cell damage accompanied by enhanced pulmonary secretions, perhaps of glycoproteins and mucins, as a result of inhalation toxicity.     

Socioeconomic status and survival for breast and cervical cancer

This paper considers the association between socioeconomic status (SES) and survival from breast and cervical cancers, two major health problems for women. For both cancers, lower SES women appear to have poorer survival. Factors which may account for this are discussed, including biological and nutritional factors. Major emphasis is placed on early detection since this appears to play a critical role in the survival differential. Factors which act as barriers to early detection among poor women are considered, including those related both to the health behaviors of the poor and to the health care system available to the poor.     

Gender and illness behavior among colorectal cancer patients

This study of 154 men and 152 women with cancer of the colon or rectum addresses the lag between the first recognition of symptoms and the securing of definitive diagnosis and treatment. Total treatment delay is divided into two categories: patient delay, or the lag between the patient's first recognition of symptoms and first physician contact; diagnostic delay, or the lag between the patient's first physician contact and treatment. The results do not support the contention that women are more prone than men to respond to cancer symptoms; women in this sample are not more likely than men to recognize and respond to symptoms and seek care. The results suggest that, among patients with cancer of the rectum, women are more likely than men to delay in seeking care. Among patients with cancer of the colon, women are more likely than men to experience diagnostic delay.     

Agonist-induced conformational changes in the extracellular domain of alpha 7 nicotinic acetylcholine receptors

The molecular mechanisms that couple agonist binding to the gating of Cys-loop ionotropic receptors are not well understood. The crystal structure of the acetylcholine (ACh) binding protein has provided insights into the structure of the extracellular domain of nicotinic receptors and a framework for testing mechanisms of activation. Key ligand binding residues are located at the C-terminal end of the beta9 strand. At the N-terminal end of this strand (loop 9) is a conserved glutamate [E172 in chick alpha7 nicotinic acetylcholine receptors (nAChRs)] that is important for modulating activation. We hypothesize that agonist binding induces the movement of loop 9. To test this, we used the substituted-cysteine accessibility method to examine agonist-dependent changes in the modification of cysteines introduced in loop 9 of L247T alpha7 nAChRs. In the absence of agonist, ACh-evoked responses of E172C/L247T alpha7 nAChRs were inhibited by 2-trimethylammonioethylmethane thiosulfonate (MTSET). Agonist coapplication with MTSET reduced the extent and rate of modification. The dose-dependence of ACh activation was nearly identical with that of ACh-dependent protection from modification. ACh increased the inhibition by methanethiosulfonate reagents of N170C and did not change inhibition of G171C receptors. The antagonist dihydro-beta-erythroidine did not mimic the effects of ACh. Combined with a structural model, the data suggest that receptor activation includes subunit rotation and/or intrasubunit conformational changes that move N170 to a more accessible position and E172 to a more protected position away from the vestibule. Thus, loop 9, located near the junction between the extracellular and transmembrane domains, participates in conformational changes triggered by ligand binding.