Updates from the 2017 American Society of Hematology Annual Meeting: Practice-Changing Studies in Relapsed and Refractory Mantle Cell Lymphoma

The 2017 annual meeting of the American Society of Hematology took place 9–12 December in Atlanta, Georgia. At the meeting, results from key studies in the treatment of relapsed and refractory mantle cell lymphoma were presented. Of those studies, oral presentations focused on the efficacy and safety of therapy with Bruton tyrosine kinase (BTK) inhibitors. One study presented pooled data from three trials using ibrutinib, with a median follow-up of 3.5 years. A second phase ii study presented data on the efficacy and safety of acalabrutinib, a highly selective BTK inhibitor with minimal off-target activity. The final study presented early phase ib data on the efficacy and safety of zanubrutinib, a novel, highly selective BTK inhibitor, in patients with non-Hodgkin lymphoma. Our meeting report describes the foregoing studies and presents interviews with investigators and commentaries by Canadian hematologists about potential effects on Canadian practice.

Updates from the 2017 American Society of Hematology Annual Meeting: Practice-Changing Studies in Untreated Chronic Lymphocytic Leukemia

The 2017 annual meeting of the American Society of Hematology took place 9–12 December in Atlanta, Georgia. At the meeting, the oral presentations included results from key studies on the first-line treatment of chronic lymphocytic leukemia. A series of phase ii studies focusing on the efficacy and safety of novel treatment strategies were especially notable. One concerned the health-related quality of life results from the gibb study, which had examined the combination of obinutuzumab and bendamustine. A second evaluated the venetoclax–ibrutinib regimen in patients with high-risk disease. The third assessed the combination of ibrutinib, fludarabine, cyclophosphamide, and obinutuzumab in patients with mutated immunoglobulin heavy-chain variable region genes. The fourth examined the combination of ibrutinib, fludarabine, cyclophosphamide, and rituximab in younger patients. And the final study evaluated obinutuzumab–ibrutinib followed by a minimal residual disease strategy in fit patients. Our meeting report describes the foregoing studies and presents interviews with investigators and commentaries by Canadian hematologists about the potential effects on Canadian practice.

Metagenomic Investigation of Idiopathic Meningoencephalomyelitis in Dogs

BACKGROUND

Meningoencephalomyelitis of unknown origin (MUO) is a common and life-threatening neuroinflammatory disease in dogs. Features of the disease are suggestive of an underlying immune-mediated process, but the association of this disease with a pathogen is still unknown.

HYPOTHESIS/OBJECTIVES

To search for candidate etiologic agent associated with cases if MUO using next generation metagenomic sequencing.

ANIMALS

Twenty-two dogs diagnosed with either MUO (11/22; 10 CSF and 3 brain), or noninflammatory CNS diseases inconsistent with MUO (11/22; 11 CSF and 2 brain) that served as negative controls.

METHODS

A case control study was performed by identifying MUO and non-MUO cases. Samples were blindly processed and then unblinded for comparative analyses. Inclusion criteria for MUO cases included consistent MRI lesions and inflammatory CSF with a negative PCR panel for infectious agents or histopathologic diagnosis. Dogs with glucocorticoid therapy within 2 weeks of sample collection were excluded. Fresh-frozen cerebrospinal fluid (CSF; 21) and brain (5) samples were collected and RNA and DNA were extracted separately for shotgun metagenomic sequencing. Known positive samples were used as controls to validate our sequencing and analysis pipelines and to establish limits of detection. Sequencing results were analyzed at a nucleotide and protein level for broad comparison to known infectious organisms.

RESULTS

No candidate etiologic agents were identified in dogs with MUO.

CONCLUSIONS AND CLINICAL IMPORTANCE

These results support but do not prove the hypothesis that MUO is not associated with infectious agents and might be an autoimmune disease.

Updates from the 2016 American Society of Hematology Annual Meeting: Practice-Changing Studies in Untreated Follicular Lymphoma

The 2016 annual meeting of the American Society of Hematology took place in San Diego, California, 3–6 December. At the meeting, results from key studies on the first-line treatment of follicular lymphoma were presented. Of those studies, key oral presentations included two analyzing data from the gallium study, which evaluated the efficacy and safety of obinutuzumab plus chemotherapy (G-chemo) compared with rituximab plus chemotherapy (R-chemo), followed, in responding patients with follicular lymphoma, by obinutuzumab or rituximab maintenance; results from the sabrina study, which evaluated the efficacy and safety of subcutaneous compared with intravenous rituximab; results of a cost-effectiveness analysis of first-line treatment with bendamustine and rituximab from a Canadian perspective; and results from the SAKK 35/10 study, which evaluated the safety and efficacy of rituximab plus lenalidomide compared with rituximab monotherapy. Our meeting report describes the foregoing studies and includes interviews with the Canadian investigators, plus commentaries by those investigators about the potential impact on Canadian practice.

Morphoea with prominent plasma cell endoneuritis

Morphoea (localized scleroderma) is a cutaneous inflammatory condition characterized by the development of indurated and discoloured plaques. The histological features of morphoea typically include a superficial and deep perivascular and periadnexal chronic inflammatory infiltrate associated with variable degrees of dermal and/or subcutaneous sclerosis. The infiltrate is typically composed of lymphocytes, macrophages and conspicuous plasma cells. The early stages of morphoea may have a very prominent inflammatory infiltrate associated with subtle sclerosis. In addition, the inflammatory infiltrate may show a perineural and rarely intraneural distribution. We report two cases of morphoea that histologically showed plasma cell endoneuritis associated with subtle dermal sclerosis. These two cases highlight the potential for diagnostic confusion with infectious and inflammatory diseases, particularly leprosy and lupus.

Regulation of growth hormone induced JAK2 and mTOR signalling by hepatic protein tyrosine phosphatase 1B

Protein tyrosine phosphatase 1B (PTP1B) regulates various signalling pathways including insulin, leptin, IGF-1 and growth hormone (GH) signalling. Transmission of the GH signal depends on Janus kinase 2 (JAK2), which is how PTP1B is thought to modulate GH signalling in the liver, based on studies utilising global PTP1B knockout mice (Ptp1b(-/-)). Here, we investigated the liver-specific role of PTP1B in GH signalling, using liver-specific Ptp1b(-/-) mice (alb-crePtp1b(-/-)), under physiological (chow) or insulin resistant (high-fat diet [HFD]) feeding conditions. Body weight and adiposity were comparable between female alb-crePtp1b(-/-) and Ptp1b(fl/fl) control mice. On chow diet, under 48-hour fasting GH-resistant conditions, GH stimulation in vivo led to a robust stimulation of the JAK-STAT signalling pathway. Alb-crePtp1b(-/-) mice exhibited significantly higher GH-induced JAK2 phosphorylation and SOCS3 gene expression post-GH stimulation. However, STAT3, STAT5 and ERK1/2 phosphorylation and SOCS2 gene expression were similar between groups. Interestingly, GH-induced mTOR phosphorylation was significantly higher in alb-crePtp1b(-/-) mice 5-min post-GH stimulation compared to controls, revealing this part of the pathway under direct control of PTP1B. Under ad lib HFD-fed conditions, GH-induced STAT5 phosphorylation significantly increased in alb-crePtp1b(-/-) mice only, with no alterations in the controls. Overall, our data demonstrate that liver-specific PTP1B deletion leads to significant alterations in GH signalling with increased JAK2, STAT5 and mTOR phosphorylation and SOCS3 gene expression.

Inducible liver-specific knockdown of protein tyrosine phosphatase 1B improves glucose and lipid homeostasis in adult mice

AIMS/HYPOTHESIS

Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signalling. Hepatic PTP1B deficiency, using the Alb-Cre promoter to drive Ptp1b deletion from birth in mice, improves glucose homeostasis, insulin sensitivity and lipid metabolism. The aim of this study was to investigate the therapeutic potential of decreasing liver PTP1B levels in obese and insulin-resistant adult mice.

METHODS

Inducible Ptp1b liver-specific knockout mice were generated using SA-Cre-ER(T2) mice crossed with Ptp1b floxed (Ptp1b(fl/fl)) mice. Mice were fed a high-fat diet (HFD) for 12 weeks to induce obesity and insulin resistance. Tamoxifen was administered in the HFD to induce liver-specific deletion of Ptp1b (SA-Ptp1b(-/-) mice). Body weight, glucose homeostasis, lipid homeostasis, serum adipokines, insulin signalling and endoplasmic reticulum (ER) stress were examined.

RESULTS

Despite no significant change in body weight relative to HFD-fed Ptp1b(fl/fl) control mice, HFD-fed SA-Ptp1b(-/-) mice exhibited a reversal of glucose intolerance as determined by improved glucose and pyruvate tolerance tests, decreased fed and fasting blood glucose and insulin levels, lower HOMA of insulin resistance, circulating leptin, serum and liver triacylglycerols, serum NEFA and decreased HFD-induced ER stress. This was associated with decreased glycogen synthase, eukaryotic translation initiation factor-2α kinase 3, eukaryotic initiation factor 2α and c-Jun NH2-terminal kinase 2 phosphorylation, and decreased expression of Pepck.

CONCLUSIONS/INTERPRETATION

Inducible liver-specific PTP1B knockdown reverses glucose intolerance and improves lipid homeostasis in HFD-fed obese and insulin-resistant adult mice. This suggests that knockdown of liver PTP1B in individuals who are already obese/insulin resistant may have relatively rapid, beneficial therapeutic effects.

Mental health impairment associated with eating-disorder features in a community sample of women

BACKGROUND AND AIMS

 Impairment in mental health associated with eating-disorder features was examined in a large, general population sample of women aged 18 to 42 years.

METHOD

 Participants (n = 5255) completed self-report measures of eating-disordered behaviour, mental health functioning, height and weight and socio-demographic information.

RESULTS

The most common eating-disorder features were extreme concerns about weight or shape (14.6%), subjective overeating (12.7%), objective overeating (10.6%) and extreme concerns about dietary intake (10.4%). In multivariable analysis, in which mental health functioning was regressed on eating-disorder features, while also controlling for age and body weight, objective overeating (β  =  -0.07), subjective overeating (β   = -0.07), extreme dietary restriction (β  =  -0.06) and extreme concerns about eating (β  =  -0.04) showed small, but statistically significant associations with mental health impairment, whereas extreme weight or shape concerns showed a very strong association (β  =  -0.24).

CONCLUSIONS

From a clinical perspective, the findings are consistent with the importance attached to the "over-evaluation" of weight or shape as a core component of eating-disorder psychopathology. From a public health perspective, the findings indicate the need to conceive of body dissatisfaction as a target for health promotion in its own right.

Long-range epigenetic silencing of chromosome 5q31 protocadherins is involved in early and late stages of colorectal tumorigenesis through modulation of oncogenic pathways

Loss of tumour suppressor gene function can occur as a result of epigenetic silencing of large chromosomal regions, referred to as long-range epigenetic silencing (LRES), and genome-wide analyses have revealed that LRES is present in many cancer types. Here we utilize Illumina Beadchip methylation array analysis to identify LRES across 800 kb of chromosome 5q31 in colorectal adenomas and carcinomas (n=34) relative to normal colonic epithelial DNA (n=6). This region encompasses 53 individual protocadherin (PCDH) genes divided among three gene clusters. Hypermethylation within these gene clusters is asynchronous; while most PCDH hypermethylation occurs early, and is apparent in adenomas, PCDHGC3 promoter methylation occurs later in the adenoma-carcinoma transition. PCDHGC3 was hypermethylated in 17/28 carcinomas (60.7%) according to methylation array analysis. Quantitative real-time reverse transcription-polymerase chain reaction showed that PCDHGC3 is the highest expressed PCDH in normal colonic epithelium, and that there was a strong reciprocal relationship between PCDHGC3 methylation and expression in carcinomas (R=-0.84). PCDH LRES patterns are reflected in colorectal tumour cell lines; adenoma cell lines are not methylated at PCDHGC3 and show abundant expression at the mRNA and protein level, while the expression is suppressed in hypermethylated carcinoma cell lines (R=-0.73). Short-interfering RNA-mediated reduction of PCDHGC3 led to a decrease of apoptosis in RG/C2 adenoma cells, and overexpression of PCDHGC3 in HCT116 cells resulted in the reduction of colony formation, consistent with tumour suppressor capabilities for PCDHGC3. Further functional analysis showed that PCDHGC3 can suppress Wnt and mammalian target of rapamycin signalling in colorectal cancer cell lines. Taken together, our data suggest that the PCDH LRES is an important tumour suppressor locus in colorectal cancer, and that PCDHGC3 may be a strong marker and driver for the adenoma-carcinoma transition.