Prognostic significance of minichromosome maintenance proteins in breast cancer.

A role for the minichromosome maintenance (MCM) proteins in cancer initiation and progression is slowly emerging. Functioning as a complex to ensure a single chromosomal replication per cell cycle, the six family members have been implicated in several neoplastic disease states, including breast cancer. Our study aim to investigate the prognostic significance of these proteins in breast cancer. We studied the expression of MCMs in various datasets and the associations of the expression with clinicopathological parameters. When considered alone, high level MCM4 overexpression was only weakly associated with shorter survival in the combined breast cancer patient cohort (n = 1441, Hazard Ratio = 1.31; 95% Confidence Interval = 1.11-1.55; p = 0.001). On the other hand, when we studied all six components of the MCM complex, we found that overexpression of all MCMs was strongly associated with shorter survival in the same cohort (n = 1441, Hazard Ratio = 1.75; 95% Confidence Interval = 1.31-2.34; p < 0.001), suggesting these MCM proteins may cooperate to promote breast cancer progression. Indeed, their expressions were significantly correlated with each other in these cohorts. In addition, we found that increasing number of overexpressed MCMs was associated with negative ER status as well as treatment response. Together, our findings are reproducible in seven independent breast cancer cohorts, with 1441 patients, and suggest that MCM profiling could potentially be used to predict response to treatment and prognosis in breast cancer patients.published_or_final_versio

Study of minichromosome-maintenance-deficient 4 (MCM4) gene in breast cancer

published_or_final_versionPathologyMasterMaster of Philosoph

Emissive behavior, cytotoxic activity, cellular uptake, and PEGylation properties of new luminescent rhenium(I) polypyridine poly(ethylene glycol) complexes

We report here a new class of biological reagents derived from luminescent rhenium(I) polypyridine complexes modified with a poly(ethylene glycol) (PEG) pendant. The PEG-amine complexes [Re(N^N)(CO)3(py-PEG- NH2)](PF6) (py-PEG-NH2 = 3-amino-5-(N-(2- (ω-methoxypoly(1-oxapropyl))ethyl)aminocarbonyl)pyridine, MWPEG = 5000 Da, PDIPEG \u3c 1.08 ; N^N = 1,10-phenanthroline (phen) (1-PEG-NH2), 3,4,7,8-tetramethyl-1,10-phenanthroline (Me 4-phen) (2-PEG-NH2), 4,7-diphenyl-1,10-phenanthroline (Ph2-phen) (3-PEG-NH2)) and [Re(bpy-PEG)(CO) 3(py-NH2)](PF6) (bpy-PEG = 4-(N-(2-(ω- methoxypoly(1-oxapropyl))ethyl)aminocarbonyl)-4′-methyl-2, 2′-bipyridine ; py-NH2 = 3-aminopyridine) (4-PEG-NH2) have been synthesized and characterized. The photophysical properties, lipophilicity, water solubility, cytotoxic activity, and cellular uptake properties of these complexes have been compared to those of their PEG-free counterparts [Re(N^N)(CO)3(py-Et-NH2)](PF 6) (py-Et-NH2 = 3-amino-5-(N-(ethyl)aminocarbonyl) pyridine ; N^N = phen (1-Et-NH2), Me4-phen (2-Et-NH2), Ph2-phen (3-Et-NH2)) and [Re(bpy-Et)(CO)3(py-NH2)](PF6) (bpy-Et = 4-(N-(ethyl)aminocarbonyl)-4′-methyl-2,2′-bipyridine) (4-Et-NH 2). The PEG complexes exhibited significantly higher water solubility and lower cytotoxicity (IC50 = 6.6 to 1152 μM) than their PEG-free counterparts (IC50 = 3.6 to 159 μM), indicating that the covalent attachment of a PEG pendant to rhenium(I) polypyridine complexes is an effective way to increase their biocompatibility. The amine complexes 1-PEG-NH2-4-PEG-NH2 have been activated with thiophosgene to yield the isothiocyanate complexes [Re(N^N)(CO) 3(py-PEG-NCS)](PF6) (py-PEG-NCS = 3-isothiocyanato-5-(N- (2-(ω-methoxypoly(1-oxapropyl))ethyl)aminocarbonyl)pyridine ; N ^N = phen (1-PEG-NCS), Me4-phen (2-PEG-NCS), Ph 2-phen (3-PEG-NCS)), and [Re(bpy-PEG)(CO)3(py-NCS)] (PF6) (py-NCS = 3-isothiocyanatopyridine) (4-PEG-NCS) as a new class of luminescent PEGylation reagents. To examine their PEGylation properties, these isothiocyanate complexes have been reacted with a model substrate n-butylamine, resulting in the formation of the thiourea complexes [Re(N ^N)(CO)3(py-PEG-Bu)](PF6) (py-PEG-Bu = 3-n-butylthioureidyl-5-(N-(2-(ω-methoxypoly(1-oxapropyl))ethyl) aminocarbonyl)pyridine ; N^N = phen (1-PEG-Bu), Me4-phen (2-PEG-Bu), Ph2-phen (3-PEG-Bu)), and [Re(bpy-PEG)(CO) 3(py-Bu)](PF6) (py-Bu = 3-n-butylthioureidylpyridine) (4-PEG-Bu). Additionally, bovine serum albumin (BSA) and poly(ethyleneimine) (PEI) have been PEGylated with the isothiocyanate complexes to yield bioconjugates 1-PEG-BSA-4-PEG-BSA and 1-PEG-PEI-4-PEG-PEI, respectively. Upon irradiation, all the PEGylated BSA and PEI conjugates exhibited intense and long-lived emission in aqueous buffer under ambient conditions. The DNA-binding and polyplex-formation properties of conjugate 3-PEG-PEI have been studied and compared with those of unmodified PEI. Furthermore, the in vivo toxicity of complex 3-PEG-NH2 and its PEG-free counterpart 3-Et-NH2 has been investigated using zebrafish embryos as an animal model. Embryos treated with the PEG complex at high concentrations revealed delayed hatching, which has been ascribed to hypoxia as a result of adhering of the complex to the external surface of the chorion

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field