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Jong-In Park

Bio: Jong-In Park is an academic researcher from Medical College of Wisconsin. The author has contributed to research in topics: MAPK/ERK pathway & Kinase. The author has an hindex of 26, co-authored 52 publications receiving 7221 citations. Previous affiliations of Jong-In Park include Johns Hopkins University School of Medicine & University of New South Wales.


Papers
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Journal ArticleDOI
Daniel J. Klionsky1, Kotb Abdelmohsen2, Akihisa Abe3, Joynal Abedin4  +2519 moreInstitutions (695)
TL;DR: In this paper, the authors present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macro-autophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: 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. For example, 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 versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase 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. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. 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. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. 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 assays, we hope to encourage technical innovation in the field.

5,187 citations

Journal ArticleDOI
TL;DR: In this article, the authors 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.
Abstract: 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.

1,129 citations

Journal Article
TL;DR: Constutive activation of STAT3 in HNSCC may use an autocrine/paracrine-activating loop mediated by IL6 and other cytokines acting through the gp130 receptor family, which may confer both proliferative and survival potential in this malignancy.
Abstract: The aberrant growth of head and neck squamous cell carcinoma (HNSCC) is often associated with the constitutive activation of signal-transducer-and-activator-of-transcription-3 (STAT3), which is believed to result from the persistent stimulation of EGF receptors that are highly expressed in squamous cell carcinoma (SCC) cells. To investigate the mechanism underlying STAT3 deregulation in HNSCC, we examined the interplay of the STAT3 and epidermal growth factor receptor (EGFR) signaling pathways using a panel of HNSCC cell lines. Although STAT3 was active in most HNSCC cell lines, only 3 of 10 HNSCC cell lines were moderately to strongly positive for activated EGFR. Even in the EGFR-positive cell lines, STAT3 activation was not dependent on EGFR activation, as STAT3 tyrosine phosphorylation levels persisted after treatment with AG1478, a chemical inhibitor of EGFR activity. Furthermore, we found that conditioned medium harvested from HNSCC cells could induce STAT3 tyrosine phosphorylation in immortalized keratinocytes regardless of the status of EGFR signaling. In contrast, blocking the cytokine gp130 coreceptor abolished STAT3 tyrosine phosphorylation in HNSCC cells and that induced by the conditioned medium. Immunodepletion studies suggested interleukin 6 (IL6) as the major autocrine/paracrine factor for STAT3 activation, which coincided with high levels of secretion of IL6 into the culture medium by these cancer cells. Treatment with a specific inhibitor of Janus kinase, AG490, in HNSCC cells led to a reduction of active STAT3 and caused significant growth retardation and apoptosis. Thus, constitutive activation of STAT3 in HNSCC may use an autocrine/paracrine-activating loop mediated by IL6 and other cytokines acting through the gp130 receptor family, which may confer both proliferative and survival potential in this malignancy.

252 citations

Journal ArticleDOI
TL;DR: Opposition roles for phosphatidylinositol 3-kinase-Akt and MEK-ERK in cartilage matrix synthesis are demonstrated and elevated levels of reactive oxygen species cause chondrocyte IGF-I resistance by altering the balance of Akt to ERK activity is suggested.

166 citations

Journal ArticleDOI
TL;DR: It is shown that cyclin-dependent kinase 5 (CDK5), a known regulator of migration in neuronal development, plays an important role in prostate cancer motility and metastasis.
Abstract: We show here that cyclin-dependent kinase 5 (CDK5), a known regulator of migration in neuronal development, plays an important role in prostate cancer motility and metastasis. P35, an activator of CDK5 that is indicative of its activity, is expressed in a panel of human and rat prostate cancer cell lines, and is also expressed in 87.5% of the human metastatic prostate cancers we examined. Blocking of CDK5 activity with a dominant-negative CDK5 construct, small interfering RNA, or roscovitine resulted in changes in the microtubule cytoskeleton, loss of cellular polarity, and loss of motility. Expression of a dominant-negative CDK5 in the highly metastatic Dunning AT6.3 prostate cancer cell line also greatly impaired invasive capacity. CDK5 activity was important for spontaneous metastasis in vivo; xenografts of AT6.3 cells expressing dominant-negative CDK5 had less than one-fourth the number of lung metastases exhibited by AT6.3 cells expressing the empty vector. These results show that CDK5 activity controls cell motility and metastatic potential in prostate cancer.

154 citations


Cited by
More filters
Journal ArticleDOI
Daniel J. Klionsky1, Kotb Abdelmohsen2, Akihisa Abe3, Joynal Abedin4  +2519 moreInstitutions (695)
TL;DR: In this paper, the authors present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macro-autophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: 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. For example, 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 versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase 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. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. 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. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. 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 assays, we hope to encourage technical innovation in the field.

5,187 citations

Journal ArticleDOI
Lorenzo Galluzzi1, Lorenzo Galluzzi2, Ilio Vitale3, Stuart A. Aaronson4  +183 moreInstitutions (111)
TL;DR: The Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives.
Abstract: Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field.

3,301 citations

Journal ArticleDOI
TL;DR: A functional classification of cell death subroutines is proposed that applies to both in vitro and in vivo settings and includes extrinsic apoptosis, caspase-dependent or -independent intrinsic programmed cell death, regulated necrosis, autophagic cell death and mitotic catastrophe.
Abstract: In 2009, the Nomenclature Committee on Cell Death (NCCD) proposed a set of recommendations for the definition of distinct cell death morphologies and for the appropriate use of cell death-related terminology, including 'apoptosis', 'necrosis' and 'mitotic catastrophe'. In view of the substantial progress in the biochemical and genetic exploration of cell death, time has come to switch from morphological to molecular definitions of cell death modalities. Here we propose a functional classification of cell death subroutines that applies to both in vitro and in vivo settings and includes extrinsic apoptosis, caspase-dependent or -independent intrinsic apoptosis, regulated necrosis, autophagic cell death and mitotic catastrophe. Moreover, we discuss the utility of expressions indicating additional cell death modalities. On the basis of the new, revised NCCD classification, cell death subroutines are defined by a series of precise, measurable biochemical features.

2,238 citations

Journal ArticleDOI
TL;DR: Tumour cells acquire the ability to proliferate uncontrollably, resist apoptosis, sustain angiogenesis and evade immune surveillance, and STAT proteins — especially STAT3 and STAT5 — regulate all of these processes and are persistence activated in a surprisingly large number of human cancers.
Abstract: Tumour cells acquire the ability to proliferate uncontrollably, resist apoptosis, sustain angiogenesis and evade immune surveillance. STAT proteins — especially STAT3 and STAT5 — regulate all of these processes and are persistently activated in a surprisingly large number of human cancers. Consequently, STAT proteins are emerging — unexpectedly — as ideal targets for cancer therapy.

2,203 citations