In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field
We have previously shown that the persistent activation of p42/p44MAPK is required to pass the G 1 restriction point in fibroblasts (Pagè s, G., Lenormand, P., L'Allemain, G., Chambard, J. C., Meloche, S., and Pouyssé gur, J. Mammalian cells express multiple mitogen-activated protein (MAP) 1 kinases that mediate the effects of extracellular signals on a wide array of biological processes. In eukaryotic cells, three distinct MAPK cascades have been described, which appear to be linked to separate signal transduction pathways resulting in the final activation of either p42/p44 MAPK
Multicenter standardization study may accelerate the implementation of ALK testing protocols across a country/region. Our data support the use of an appropriately validated IHC assay to screen for ALK+ lung cancers.
Werner syndrome is a rare disorder characterized by the premature onset of a number of age-related diseases. The gene responsible for Werner syndrome encodes a DNA helicase/exonuclease protein. Participation in a replication complex is among the several functions postulated for the WRN protein. The poly(ADP-ribose) polymerase-1 (PARP-1) enzyme, which is known to bind to DNA strand breaks, is also associated with the DNA replication complex. To determine whether Wrn and PARP-1 enzymes act in concert during cell growth, mice with a mutation in the helicase domain of the Wrn gene (Wrn(Deltahel/Deltahel) mice) were crossed to PARP-1-null mice. Both Wrn(Deltahel/Deltahel) and PARP-1-null/Wrn(Deltahel/Deltahel) cohorts developed more neoplasms than wild-type animals. The tumor spectrum was the same between PARP-1-null/Wrn(Deltahel/Deltahel) mice and Wrn mutants. However, PARP-1-null/Wrn(Deltahel/Deltahel) mice developed neoplasms at a younger age. Mouse embryonic fibroblasts derived from such PARP-1-null/Wrn(Deltahel/Deltahel) mice stop dividing abruptly unlike Wrn(Deltahel/Deltahel) or PARP-1-null cells. PARP-1-null/Wrn(Deltahel/Deltahel) fibroblasts were distinguished by an increased frequency of chromatid breaks, complex chromosomal rearrangements, and fragmentation. Finally, experiments have indicated that the PARP-1 enzyme co-immunoprecipitates with the WRN protein in human 293 embryonic kidney cells. These results suggest that Wrn and PARP-1 enzymes may be part of a complex involved in the processing of DNA breaks.
A patient received a diagnosis of adenocarcinoma of the ampulla of Vater at 34 years of age. Two decades later, adenomatous polyps were found, followed by multiple primary invasive adenocarcinomas of both the colon and the stomach. Premature chromatid separation and mosaic variegated aneuploidy, combined with structural chromosomal abnormalities, were detected in his cells. We identified a germline homozygous intronic mutation, c.2386-11A→G, in the spindle-assembly checkpoint gene BUB1B, which creates a de novo splice site that is favored over the authentic (i.e., preferentially used) site. Our findings expand the phenotype associated with BUB1B mutations and the mosaic variegated aneuploidy syndrome to include common adult-onset cancers and provide evidence for the interdependency of the APC protein (encoded by the adenomatous polyposis coli gene) and the BUBR1 protein (encoded by BUB1B) in humans. (Funded by the Turner Family Cancer Research Fund and others.).
Previous studies have implicated vestigial like 3 (VGLL3), a chromosome 3p12.3 gene that encodes a putative transcription co-factor, as a candidate tumor suppressor gene (TSG) in high-grade serous ovarian carcinomas (HGSC), the most common type of epithelial ovarian cancer. A complementation analysis based on microcell-mediated chromosome transfer (MMCT) using a centric fragment of chromosome 3 (der3p12-q12.1) into the OV-90 ovarian cancer cell line haploinsufficient for 3p and lacking VGLL3 expression was performed to assess the effect on tumorigenic potential and growth characteristics. Genetic characterization of the derived MMCT hybrids revealed that only the hybrid that contained an intact VGLL3 locus exhibited alterations of tumorigenic potential in a nude mouse xenograft model and various in vitro growth characteristics. Only stable OV-90 transfectant clones expressing low levels of VGLL3 were derived. These clones exhibited an altered cytoplasmic morphology characterized by numerous single membrane bound multivesicular-bodies (MVB) that were not attributed to autophagy. Overexpression of VGLL3 in OV-90 was achieved using a lentivirus-based tetracycline inducible gene expression system, which also resulted in MVB formation in the infected cell population. Though there was no significant differences in various in vitro and in vivo growth characteristics in a comparison of VGLL3-expressing clones with empty vector transfectant controls, loss of VGLL3 expression was observed in tumors derived from mouse xenograft models. VGLL3 gene and protein expression was significantly reduced in HGSC samples (>98%, p < 0.05) relative to either normal ovarian surface epithelial cells or epithelial cells of the fallopian tube, possible tissues of origin of HGSC. Also, there appeared to be to be more cases with higher staining levels in stromal tissue component from HGSC cases that had a prolonged disease-free survival. The results taken together suggest that VGLL3 is involved in tumor suppressor pathways, a feature that is characterized by the absence of VGLL3 expression in HGSC samples.
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