Proteomic profile of KSR1-regulated signalling in response to genotoxic agents in breast cancer

Kinase suppressor of Ras 1 (KSR1) has been implicated in tumorigenesis in multiple cancers, including skin, pancreatic and lung carcinomas. However, our recent study revealed a role of KSR1 as a tumour suppressor in breast cancer, the expression of which is potentially correlated with chemotherapy response. Here, we aimed to further elucidate the KSR1-regulated signalling in response to genotoxic agents in breast cancer. Stable isotope labelling by amino acids in cell culture (SILAC) coupled to high-resolution mass spectrometry (MS) was implemented to globally characterise cellular protein levels induced by KSR1 in the presence of doxorubicin or etoposide. The acquired proteomic signature was compared and GO-STRING analysis was subsequently performed to illustrate the activated functional signalling networks. Furthermore, the clinical associations of KSR1 with identified targets and their relevance in chemotherapy response were examined in breast cancer patients. We reveal a comprehensive repertoire of thousands of proteins identified in each dataset and compare the unique proteomic profiles as well as functional connections modulated by KSR1 after doxorubicin (Doxo-KSR1) or etoposide (Etop-KSR1) stimulus. From the up-regulated top hits, several proteins, including STAT1, ISG15 and TAP1 are also found to be positively associated with KSR1 expression in patient samples. Moreover, high KSR1 expression, as well as high abundance of these proteins, is correlated with better survival in breast cancer patients who underwent chemotherapy. In aggregate, our data exemplify a broad functional network conferred by KSR1 with genotoxic agents and highlight its implication in predicting chemotherapy response in breast cancer

Stat1 Phosphorylation Determines Ras Oncogenicity by Regulating p27Kip1

Inactivation of p27Kip1 is implicated in tumorigenesis and has both prognostic and treatment-predictive values for many types of human cancer. The transcription factor Stat1 is essential for innate immunity and tumor immunosurveillance through its ability to act downstream of interferons. Herein, we demonstrate that Stat1 functions as a suppressor of Ras transformation independently of an interferon response. Inhibition of Ras transformation and tumorigenesis requires the phosphorylation of Stat1 at tyrosine 701 but is independent of Stat1 phosphorylation at serine 727. Stat1 induces p27Kip1 expression in Ras transformed cells at the transcriptional level through mechanisms that depend on Stat1 phosphorylation at tyrosine 701 and activation of Stat3. The tumor suppressor properties of Stat1 in Ras transformation are reversed by the inactivation of p27Kip1. Our work reveals a novel functional link between Stat1 and p27Kip1, which act in coordination to suppress the oncogenic properties of activated Ras. It also supports the notion that evaluation of Stat1 phosphorylation in human tumors may prove a reliable prognostic factor for patient outcome and a predictor of treatment response to anticancer therapies aimed at activating Stat1 and its downstream effectors

The Biochemical and Cellular Basis for Nutraceutical Strategies to Attenuate Neurodegeneration in Parkinson’s Disease

Future therapeutic intervention that could effectively decelerate the rate of degeneration within the substantia nigra pars compacta (SNc) could add years of mobility and reduce morbidity associated with Parkinson’s disease (PD). Neurodegenerative decline associated with PD is distinguished by extensive damage to SNc dopaminergic (DAergic) neurons and decay of the striatal tract. While genetic mutations or environmental toxins can precipitate pathology, progressive degenerative succession involves a gradual decline in DA neurotransmission/synaptic uptake, impaired oxidative glucose consumption, a rise in striatal lactate and chronic inflammation. Nutraceuticals play a fundamental role in energy metabolism and signaling transduction pathways that control neurotransmission and inflammation. However, the use of nutritional supplements to slow the progression of PD has met with considerable challenge and has thus far proven unsuccessful. This review re-examines precipitating factors and insults involved in PD and how nutraceuticals can affect each of these biological targets. Discussed are disease dynamics (Sections 1 and 2) and natural substances, vitamins and minerals that could impact disease processes (Section 3). Topics include nutritional influences on α-synuclein aggregation, ubiquitin proteasome function, mTOR signaling/lysosomal-autophagy, energy failure, faulty catecholamine trafficking, DA oxidation, synthesis of toxic DA-quinones, o-semiquinones, benzothiazolines, hyperhomocyseinemia, methylation, inflammation and irreversible oxidation of neuromelanin. In summary, it is clear that future research will be required to consider the multi-faceted nature of this disease and re-examine how and why the use of nutritional multi-vitamin-mineral and plant-based combinations could be used to slow the progression of PD, if possible

Abnormal VWF modifies megakaryocytopoiesis: studies of platelets and megakaryocyte cultures from patients with von Willebrand disease type 2B

von Willebrand factor (VWF) is an essential mediator of platelet adhesion to the vessel wall, but little is known about its role in megakaryocytopoiesis. VWF and its platelet receptor, glycoprotein Ibα(GPIbα), are both expressed during megakaryocyte (MK) maturation. This study was designed to evaluate whether the enhanced VWF-GPIbα interactions typical of patients with von Willebrand disease type 2B (VWD2B) modify platelet production. Platelets from 9 patients with VWD2B with 7 different gain-of-function mutations were examined by electron microscopy (EM) and immunofluorescence labeling. For the patients with VWD2B, EM characteristically showed variable numbers of structurally abnormal giant platelets, sometimes in agglutinates. Cultures of MKs from controls performed with or without purified VWF confirmed a positive influence of VWF on platelet production with specific inhibition by an antibody blocking VWF binding to GPIbα. VWD2B MK cultures examined by EM showed a disorganized demarcation membrane system and abnormal granule distribution. They produced platelets with structural abnormalities typical of VWD2B. Confocal examination of MK revealed limited extension of pseudopods with few large proplatelets. These results confirm that megakaryocytopoiesis is modified by the enhanced VWF-GPIbα interactions.These data obtained for controls and patients with VWD2B suggest a novel regulatory role of VWF-GPIbα interactions in platelet production

Abnormal VWF modifies megakaryocytopoiesis : studies of platelets and megakaryocyte cultures from patients with von Willebrand disease type 2B

von Willebrand factor (VWF) is an essential mediator of platelet adhesion to the vessel wall, but little is known about its role in megakaryocytopoiesis. VWF and its platelet receptor, glycoprotein Ib\u3b1 (GPIb\u3b1), are both expressed during megakaryocyte (MK) maturation. This study was designed to evaluate whether the enhanced VWF-GPIb\u3b1 interactions typical of patients with von Willebrand disease type 2B (VWD2B) modify platelet production. Platelets from 9 patients with VWD2B with 7 different gain-of-function mutations were examined by electron microscopy (EM) and immunofluorescence labeling. For the patients with VWD2B, EM characteristically showed variable numbers of structurally abnormal giant platelets, sometimes in agglutinates. Cultures of MKs from controls performed with or without purified VWF confirmed a positive influence of VWF on platelet production with specific inhibition by an antibody blocking VWF binding to GPIb\u3b1. VWD2B MK cultures examined by EM showed a disorganized demarcation membrane system and abnormal granule distribution. They produced platelets with structural abnormalities typical of VWD2B. Confocal examination of MK revealed limited extension of pseudopods with few large proplatelets. These results confirm that megakaryocytopoiesis is modified by the enhanced VWF-GPIb\u3b1 interactions. These data obtained for controls and patients with VWD2B suggest a novel regulatory role of VWF-GPIb\u3b1 interactions in platelet production

Splenic marginal zone lymphomas and lymphoplasmacytic lymphomas originate from B-cell compartments with two different antigen-exposure histories.

International audienc

IGHV gene features and MYD88 L265P mutation separate the three marginal zone lymphoma entities and Waldenström macroglobulinemia/lymphoplasmacytic lymphomas.

International audienceTo clarify the relationships between marginal zone lymphomas (MZLs) and Waldenström macroglobulinemia/lymphoplasmacytic lymphomas (WM/LPLs), immunoglobulin heavy chain variable gene (IGHV) features were analyzed and the occurrence of MYD88 L265P mutations was identified in a series of 123 patients: 53 MZLs from the spleen (SMZLs), 11 from lymph nodes (NMZLs), 28 mucosa-associated lymphatic tissue (MALT) lymphomas and 31 WM/LPLs. SMZLs were characterized by overrepresentation of IGHV1-2 gene rearrangements with a canonical motif, without selection pressure and with long CDR3 segments. NMZLs had increased frequencies of IGHV3 genes. The IGHV gene was unmutated in most cases, often with long CDR3 segments. MALT lymphomas were usually associated with a mutated IGHV gene, but with the absence of selection pressure. WM/LPLs were associated with an IGHV3-23 overrepresentation and high IGHV mutation rate, with features of selection pressure and short CDR3 segments. MYD88 L265P mutations were almost restricted exclusively to WM/LPL patients. Taken all diagnoses together, all patients with MYD88 L265P mutations had an immunoglobulin M peak and almost all patients except one had bone marrow infiltration. These results demonstrate that the history of antigen exposure of the four entities studied was different and MYD88 L265P was specifically associated with WM/LPLs. WM/LPL may thus be functionally associated with constitutive nuclear factor-κB activation