Therapeutic potential of spleen tyrosine kinase inhibition for treatment of high-risk precursor B-cell acute lymphoblastic leukemia
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ABSTRACT: This study revealed pathogenic role of pre-BCR-independent SYK activation in high-risk B-ALL. Intensified and central nervous system (CNS)-directed chemotherapy has significantly improved outcomes for pediatric B-acute lymphoblastic leukemia (B-ALL), but confers significant late-effect morbidities. Moreover, many patients suffer relapses, underscoring the need to develop novel, molecularly targeted B-ALL therapies. Using a mouse model, we showed that leukemic B-cells require pre-B-cell receptor (pre-BCR)-independent spleen tyrosine kinase (SYK) signaling in vivo. In diagnostic samples from human B-ALL patients, SYK and downstream targets were phosphorylated regardless of pre-BCR expression or genetic subtype. Two small molecule SYK inhibitors, fostamatinib and BAY61-3606, attenuated growth of 69 B-ALL samples, including high-risk (HR) subtypes. Orally administered fostamatinib significantly reduced high disease burden after xenotransplantation of HR B-ALL samples into immune-deficient mice, and decreased leukemia dissemination into spleen, liver, kidneys and the CNS of recipients. Thus, SYK activation sustains growth of multiple HR B-ALL subtypes, suggesting that SYK inhibitors may improve outcomes for HR and relapsed B-ALL. B-cell leukemia samples (3) from a mutant mouse model were compared to sorted or cultured preB or proB cells from normal mice using Affymetrix GeneChip arrays.
Project description:This study revealed pathogenic role of pre-BCR-independent SYK activation in high-risk B-ALL. Intensified and central nervous system (CNS)-directed chemotherapy has significantly improved outcomes for pediatric B-acute lymphoblastic leukemia (B-ALL), but confers significant late-effect morbidities. Moreover, many patients suffer relapses, underscoring the need to develop novel, molecularly targeted B-ALL therapies. Using a mouse model, we showed that leukemic B-cells require pre-B-cell receptor (pre-BCR)-independent spleen tyrosine kinase (SYK) signaling in vivo. In diagnostic samples from human B-ALL patients, SYK and downstream targets were phosphorylated regardless of pre-BCR expression or genetic subtype. Two small molecule SYK inhibitors, fostamatinib and BAY61-3606, attenuated growth of 69 B-ALL samples, including high-risk (HR) subtypes. Orally administered fostamatinib significantly reduced high disease burden after xenotransplantation of HR B-ALL samples into immune-deficient mice, and decreased leukemia dissemination into spleen, liver, kidneys and the CNS of recipients. Thus, SYK activation sustains growth of multiple HR B-ALL subtypes, suggesting that SYK inhibitors may improve outcomes for HR and relapsed B-ALL.
Project description:In many mammals, halogenated aromatic hydrocarbon (HAH) exposure causes wasting syndrome, defined as lethal weight loss as a result of severe and persistent hypophagia. The most potent HAH in causing wasting is 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), which exerts its toxic effects through the aryl hydrocarbon receptor (AHR) – a transcription factor. Because TCDD toxicity is thought to predominantly arise from dysregulation of AHR-transcribed genes, we hypothesized that wasting syndrome is due to TCDD-induced dysregulation of genes involved in regulation of food-intake. We therefore focused on the hypothalamus, as it is the regulatory center of food-intake and energy balance in the central nervous system. We profiled mRNA abundance in hypothalamic tissue from two rat strains with widely differing sensitivities to wasting syndrome: TCDD-sensitive Long-Evans rats and TCDD-resistant Han/Wistar rats, 23 hours after exposure to TCDD (100 μg/kg) or corn oil vehicle. We found that TCDD exposure caused minimal transcriptional dysregulation effects in the hypothalamus, with only 6 genes changed in Long-Evans rats and 15 genes in Han/Wistar rats. Two of the most dysregulated genes were Cyp1a1 and Nqo1, which are induced by TCDD across a wide range of tissues and are considered sensitive markers of TCDD exposure. The minimal response of the hypothalamic transcriptome to a lethal dose of TCDD at an early time-point suggests that the hypothalamus is not the predominant site of initial events leading to hypophagia and associated wasting. TCDD may affect feeding behaviour via events upstream or downstream of the hypothalamus, and further work is required to evaluate this at the level of individual hypothalamic nuclei and subregions. Two strains, each with drug-treated vs vehicle-control
Project description:Metastasis is responsible for the majority of deaths in a variety of cancer types, including breast cancer. Although several factors or biomarkers have been identified to predict the outcome of patients with breast cancer, few studies have been conducted to identify metastasis-associated biomarkers. Quantitative iTRAQ proteomics analysis was used to detect differentially expressed proteins between lymph node metastases and their paired primary tumor tissues from 23 patients with metastatic breast cancer. Immunohistochemistry was performed to validate the expression of two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins in 190 paraffin-embedded tissue samples. These four proteins were further analyzed for their correlation with clinicopathological features in 190 breast cancer patients. We identified 637 differentially regulated proteins (397 upregulated and 240 downregulated) in lymph node metastases compared with their paired primary tumor tissues. Furthermore, bioinformatics analysis using GEO profiling confirmed the difference in the expression of EpCAM between metastases and primary tumors tissues. Two upregulated (EpCAM, FADD) and two downregulated (NDRG1, αB-crystallin) proteins were associated with the progression of breast cancer. Obviously, EpCAM plays a role in the metastasis of breast cancer cells to the lymph node. We further identified αB-crystallin as an independent biomarker to predict lymph node metastasis and the outcome of breast cancer patients.
Project description:2,3,7,8M-bM-^@M-^Stetrachlorodibenzo-p-dixion (TCDD) is a dioxin congener that causes a wide range of toxic effects in rodent species. Previous studies discovered that males and females of the same species display different sensitivities to TCDD exposure. Although it is now clear that most TCDD-induced toxic outcomes are mediated by the Aryl Hydrocarbon Receptor (AHR), a transcription factor, the mechanism of sex-specific responses to TCDD remains largely unknown. To understand the differential sensitivity in male and female animals, we profiled the hepatic transcriptomic responses to single doses of TCDD (125, 250, 500, or 1000 M-BM-5g/kg) in male and female C57BL6 mice. Several key findings were revealed by our study: 1) transcriptomic profiles varied largely between sexes at all doses; 2) the mRNA abundance profiles of female mice were less altered from basal level; 3) the alteration of M-bM-^@M-^XAHR-coreM-bM-^@M-^Y genes were consistent regardless of sex; 4) a list of sex-specific TCDD-responsive genes were identified, including Fmo3 and Nr1i3 upregulated in male mice and Sult3a1 downregulated in female mice; 5) functional analysis of these candidate genes showed various biological pathway enrichments in a sex-dependent manner. Our study shows that the sex-dependent sensitivities to TCDD exposure are associated with a set of sex-specific TCDD-responsive genes that are indirectly regulated by AHR activity. The exact roles of these genes in response to TCDD exposure are not clear and require further investigation. Adult male and female C57BL/6 mice were treated by gavage with one single-dose TCDD (125, 250, 500, or 1000 M-NM-<g/kg) in corn oil or corn oil vehicle alone. Animals were euthanized at 96 hours after treatment and tissues were harvested. RNA was isolated from hepatic tissue and the transcriptome for each animal assayed on an individual microarray.
Project description:2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that produces myriad toxicities across various experimental models. In rodents alone, there is huge divergence in the toxicological response across species, between strains within a species and even between sexes within a strain. This difference in sensitivities between sexes has been characterized in multiple rodent models, however with contrasting results: the severity of toxicity is greater in female rats than in males while male mice and guinea pigs are more sensitive to the effects of TCDD than females. While the presence of estrogens or androgens has a known impact on response, the specific transcriptional events that cause this difference remain unclear. We sought to characterize the transcriptional environment of male and female C57BL/6 mice treated with 500 M-NM-<g/kg TCDD and followed across a time-course. This dose was chosen as it is greater than the LD50 for male mice yet produces minimal effects in females. Additionally, evaluation along a time-course allows for the detection of specific changes that occur throughout the development of phenotypic toxicities. The transcriptional profile across the time-course was highly divergent between the sexes. Female TCDD-treated mice demonstrated a large number of altered transcripts as early as 6 hours following treatment, suggesting a large primary response, possibly indicative of the activation of numerous defense mechanisms. Conversely, male animals showed the greatest TCDD-mediated response 144 hours following exposure, potentially implicating significant secondary responses for the increased appearance of TCDD toxicities. Nr1i3 is statistically significantly altered at all time-points in the sensitive male animals. This mRNA encodes a transcription factor (constitutive androstane receptor; CAR) involved in the regulation of xenobiotic metabolism, as well as lipid metabolism, cell cycle and apoptosis. In particular, increased levels of CAR may result in induction of the anti-apoptotic gene Gadd45b and carboxylesterase Ces1d, both of which we identify as transcriptionally altered and may be responsible for phenotypic hepatic abnormalities, such as steatohepatitis and tumor formation. Further evaluation across studies of mice and rats into the role of Nr1i3 and associated genes are crucial to enhance our understanding of various TCDD-induced toxicities. Adult male and female C57BL/6 mice were treated by gavage with either 500 ug/kg TCDD in corn oil or corn oil vehicle alone. Animals were euthanized at either 6, 24, 72 or 144 hours after treatment and tissues were harvested. RNA was isolated from hepatic tissue and the transcriptome for each animal assayed on an individual microarray. Please note that 7 samples (out of total 65 samples) were identified as outliers and therefore the data were processed without the outliers as well. The normalized data without outliers were provided in the 'normalized_data_without_outliers.txt' file.
Project description:The aryl hydrocarbon receptor (AHR) mediates most of the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, TCDD toxicity phenotypes vary widely between species, strains and even between sexes within a strain. While the exact reasons for this variation remain unclear, it is thought to be related to differences in the structure of the AHR. Previous studies comparing the downstream effects of TCDD exposure between animals with different AHR isoforms have been confounded by the genetic differences between these model systems. To address this issue conclusively, we evaluated three transgenic mouse lines, each of which express a different rat AHR isoform (rWT, DEL, and INS) from two strains of rat with highly divergent TCDD-susceptibilities, within identical genetic backgrounds. Here we profile hepatic transcriptomic responses following exposure to TCDD, and use these to identify transcripts associated with toxicity. We have confirmed that the variation in toxicity is inherent to the AHR isoform. Additionally, we note the enhanced activity of the modified transactivation domain of the DEL isoform, relative to the INS isoform, and provide further evidence that the INS isoform is responsible for the high resistance to TCDD observed in H/W rats. We also uncover several candidate genes that were consistently differentially expressed in TCDD-sensitive mice and rats. Adult male transgenic mice were treated by gavage with 0, 125, 250, 500, or 1000 µg/kg TCDD dissolved in corn oil vehicle. Mice were euthanized 4 days following treatment and liver tissue was harvested for analysis. RNA was isolated and the transcriptome for each animal assayed on separate microarrays.
Project description:B cell receptor (BCR)-sequencing from 3 donors with prostate cancer. The sources are Peripheral blood B cells (P), tumour draining lymph nodes (S) and non-draining lymph nodes (N).
Project description:The dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a wide range of toxic effects in rodent species, all of which are mediated by a ligand-dependent transcription-factor, the aryl hydrocarbon receptor (AHR). The Han/Wistar (Kuopio) (H/W) strain shows exceptional resistance to many TCDD-induced toxicities; the LD50 of >9600 µg/kg for H/W rats is higher than for any other wild-type mammal known. We have previously shown that this resistance primarily results from H/W rats expressing a variant AHR isoform that has a substantial portion of the AHR transactivation domain deleted. Despite this large deletion, H/W rats are not entirely refractory to the effects of TCDD; the variant AHR in these animals remains fully competent to up-regulate well-known dioxin-inducible genes. TCDD-sensitive (Long-Evans, L-E) and resistant (H/W) rats were treated with either corn-oil (with or without feed-restriction) or 100 µg/kg TCDD for either four or ten days. Hepatic transcriptional profiling was done using microarrays, and was validated by RT-PCR analysis of 41 genes. . A core set of genes was altered in both strains at all time points tested, including CYP1A1, CYP1A2, CYP1B1, Nqo1, Aldh3a1, Tiparp, Exoc3, and Inmt. Outside this core, the strains differed significantly in the breadth of response: three-fold more genes were altered in L-E than H/W rats. At ten days almost all expressed genes were dysregulated in L-E rats, likely reflecting emerging toxic responses. Far fewer genes were affected by feed-restriction, suggesting that only a minority of the TCDD-induced changes are secondary to the wasting syndrome. Rats from sensitive (Long-Evans, LE) and resistant (Han/Wistar, HW) strains were treated with 100 ug/kg TCDD or corn oil vehicle and sacrificed either 4 or 10 days after treatment. LE control rats were either fed normally or feed-restricted to control for the wasting effects of TCDD treatment. Each treatment group contains four or five animals (biological replicates), each of which was assayed on an individual microarray.
Project description:Rodents exposed to the environmental contaminant, TCDD, suffer from a number of acute and chronic toxicities, including lethality and a wasting syndrome. Hypothesizing that the wasting syndrome may be caused by changes in neural control of energy flux and metabolism, we profiled the transcriptional response of rat hypothalamus to TCDD. We employed two separate rat strains: the Long-Evans strain is sensitive to TCDD toxicities while the Han/Wistar strain is over four orders of magnitude more resistant. Surprisingly, few transcriptional changes were induced by TCDD in either strain. Only four genes were altered in Long-Evans rats, including three classic TCDD-responsive genes: Cyp1a1, Cyp1b1, and Nqo1. These three genes were also altered in Han/Wistar rats, along with 133 additional genes. However, the magnitudes of alteration of these additional genes was very modest, with most changes well below two-fold in magnitude. We therefore concluded that rat hypothalamus is mostly refractory to TCDD exposure, at least at the doses and time-points surveyed here. Two strains, each with drug-treated vs. vehicle-control
Project description:Rodents exposed to the environmental contaminant, TCDD, suffer from a number of acute and chronic toxicities, including lethality and a wasting syndrome. Hypothesizing that the wasting syndrome may be caused by changes in adipose tissue -- either in its hormonal regulation or in homeostatic effects -- we profiled the transcriptional response of rat white adipose to TCDD. We employed two separate rat strains: the Long-Evans strain is sensitive to TCDD toxicities while the Han/Wistar strain is over four orders of magnitude more resistant. One day after TCDD exposure few genes were altered in either strain, but after four days a modest number of transcriptional alterations were observed. Strikingly, TCDD had far fewer effects than did a feed-restriction protocol intended to mimic the wasting syndrome itself. Notably several classic TCDD-responsive genes were modulated at all time-points, including Cyp1a1, Cyp1b1, and Nqo1. We therefore concluded that rat adipose tissue is unlikely to be the primary driver of the wasting syndrome, and that another tissue is likely involved. Two strains, each with drug-treated vs. vehicle-control