Molecular mechanism of feline calicivirus induced apoptosis

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

NOXA contributes to the sensitivity of PERK-deficient cells to ER stress.

PKR-like ER kinase (PERK) deficient mouse embryonic fibroblasts (MEFs) are hypersensitive to ER stress-induced apoptosis. However, the molecular determinants of increased sensitivity of PERK(-/-) MEFs are not clearly understood. Here we show that induction of several Unfolded Protein Response (UPR) target genes is attenuated in PERK(-/-) MEFs. We also report elevated expression of the BH3-only protein, NOXA in PERK(-/-) MEFs. Further, shRNA-mediated knockdown of NOXA rescued the hypersensitivity of PERK(-/-) MEFs to ER stress-induced apoptosis. Taken together our results suggest that compromised induction of UPR and increased NOXA expression contributes to hypersensitivity of PERK(-/-) MEFs to ER stress-induced apoptosis

Successful venetoclax salvage in the setting of refractory, dialysis-dependent multiple myeloma with t(11;14)

This Case Report illustrates the ability to salvage high risk, multi-refractory t(11;14) patients with venetoclax. The depth of the response achieved indicates the importance of BCL-2 in mediating resistance in some patients with t(11;14) and suggests that at least in this patient population any risk of increased infection is likely justified by the potential benefit. Finally, our ability to administer this drug in the setting of ESRF argues for further studies evaluating the safety of venetoclax in patients with reduced renal function

Hypersialylation and multiple myeloma

There is growing recognition of the importance of sialylation as a critical post translational modification in cancer. In this article we review the role of increased cell surface sialylation (hypersialylation) in Multiple Myeloma as it relates to cellular trafficking and immune evasion. Knowledge of the specific effects of sialic acid on cell trafficking machinery and modulation of immune cell interactions will identify opportunities for therapeutic interventions. The available evidence indicates that hypersialylation facilitates disease progression and negatively impacts on response to treatment and overall survival. Further research is required to fully elucidate the mechanisms through which hypersialylation influences disease biology and therapy resistance with the ultimate goal of developing new treatment approaches to improve the outcomes of patients with Multiple Myeloma

A cell culture system that mimics chronic lymphocytic leukemia cells microenvironment for drug screening and characterization

: Chronic Lymphocytic Leukaemia (CLL) is an incurable disease that warrants new therapeutic treatments. CLL cells accumulate in the peripheral blood, in the bone marrow and in secondary lymphoid organs. Unlike circulating CLL cells, CLL cells resident in these last two compartments display high chemoresistance and proliferative capacity. Given the importance of the microenvironment in this disease, strategies that aim to develop new therapeutic agents need to consider this critical factor. Various cell culture conditions have been described that attempt to emulate either the different types of microenvironments in which CLL cells are found or an individual component of a particular microenvironment. Here, a methodology that partially mimics the interaction between CLL cells and the CD3+ CD4+ CD154+ T cells is described. Moreover, within this method, two protocols are presented and compared that may partially recapitulate different physiological states. The methodology can be exploited for target validation and drug development in CLL

Targeting selectins and their ligands in cancer

Aberrant glycosylation is a hallmark of cancer cells with increased evidence pointing to a role in tumor progression. In particular, aberrant sialylation of glycoproteins and glycolipids has been linked to increased immune cell evasion, drug evasion, drug resistance, tumor invasiveness, and vascular dissemination, leading to metastases. Hypersialylation of cancer cells is largely the result of overexpression of sialyltransferases (STs). Differentially, humans express twenty different STs in a tissue-specific manner, each of which catalyzes the attachment of sialic acids via different glycosidic linkages (alpha 2-3, (alpha 2-6, or (alpha 2-8) to the underlying glycan chain. One important mechanism whereby over expression of STs contributes to an enhanced metastatic phenotype is via the generation of selectin ligands. Selectin ligand function requires the expression of sialyl-Lewis X and its structural isomer sialyl-Lewis A, which are synthesized by the combined action of alpha alpha 1-3-fucosyltransferases, alpha 2-3-sialyltransferases, [beta-4-galactosyltranferases, and N-acetyl-beta-glucosaminyltransferases. The alpha 2-3-sialyltransferases ST3Gal4 and ST3Gal6 are critical to the generation of functional E- and P-selectin ligands and overexpression of these STs have been linked to increased risk of metastatic disease in solid tumors and poor outcome in multiple myeloma. Thus, targeting selectins and their ligands as well as the enzymes involved in their generation, in particular STs, could be beneficial to many cancer patients. Potential strategies include ST inhibition and the use of selectin antagonists, such as glycomimetic drugs and antibodies. Here, we review ongoing efforts to optimize the potency and selectivity of ST inhibitors, including the potential for targeted delivery approaches, as well as evaluate the potential utility of selectin inhibitors, which are now in early clinical development

Targeting selectins and their ligands in cancer

Aberrant glycosylation is a hallmark of cancer cells with increased evidence pointing to a role in tumor progression. In particular, aberrant sialylation of glycoproteins and glycolipids has been linked to increased immune cell evasion, drug evasion, drug resistance, tumor invasiveness, and vascular dissemination, leading to metastases. Hypersialylation of cancer cells is largely the result of overexpression of sialyltransferases (STs). Differentially, humans express twenty different STs in a tissue-specific manner, each of which catalyzes the attachment of sialic acids via different glycosidic linkages (alpha 2-3, (alpha 2-6, or (alpha 2-8) to the underlying glycan chain. One important mechanism whereby over expression of STs contributes to an enhanced metastatic phenotype is via the generation of selectin ligands. Selectin ligand function requires the expression of sialyl-Lewis X and its structural isomer sialyl-Lewis A, which are synthesized by the combined action of alpha alpha 1-3-fucosyltransferases, alpha 2-3-sialyltransferases, [beta-4-galactosyltranferases, and N-acetyl-beta-glucosaminyltransferases. The alpha 2-3-sialyltransferases ST3Gal4 and ST3Gal6 are critical to the generation of functional E- and P-selectin ligands and overexpression of these STs have been linked to increased risk of metastatic disease in solid tumors and poor outcome in multiple myeloma. Thus, targeting selectins and their ligands as well as the enzymes involved in their generation, in particular STs, could be beneficial to many cancer patients. Potential strategies include ST inhibition and the use of selectin antagonists, such as glycomimetic drugs and antibodies. Here, we review ongoing efforts to optimize the potency and selectivity of ST inhibitors, including the potential for targeted delivery approaches, as well as evaluate the potential utility of selectin inhibitors, which are now in early clinical development