Alexander Chacon

Dr. Alexander Chacon

University of Rochester Medical Center
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 December 2014 in American Journal of Physiology-Endocrinology and Metabolism
Verified
Journal Article
Closed access
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JDJohn J. Dubé
John J. Dubé
PCPaul M. Coen
Paul M. Coen
GDGiovanna Distefano
Giovanna Distefano
Alexander ChaconAlexander Chacon
Alexander Chacon
NHNicole L. Helbling
Nicole L. Helbling
BGBret H. Goodpaster
Bret H. Goodpaster
We hypothesized that acute lipid-induced insulin resistance would be attenuated in high-oxidative muscle of lean trained (LT) endurance athletes due to their enhanced metabolic flexibility and mitochondrial capacity. Lean sedentary (LS), obese sedentary (OS), and LT participants completed two hyperinsulinemic euglycemic clamp studies with and without (glycerol control) the coinfusion of Intralipid. Metabolic flexibility was measured by indirect calorimetry as the oxidation of fatty acids and glucose during fasted and insulin-stimulated conditions, the latter with and without lipid oversupply. Muscle biopsies were obtained for mitochondrial and insulin-signaling studies. During hyperinsulinemia without lipid, glucose infusion rate (GIR) was lowest in OS due to lower rates of nonoxidative glucose disposal (NOGD), whereas state 4 respiration was increased in all groups. Lipid infusion reduced GIR similarly in all subjects and reduced state 4 respiration. However, in LT subjects, fat oxidation was higher with lipid oversupply, and although glucose oxidation was reduced, NOGD was better preserved compared with LS and OS subjects. Mitochondrial performance was positively associated with better NOGD and insulin sensitivity in both conditions. We conclude that enhanced mitochondrial performance with exercise is related to better metabolic flexibility and insulin sensitivity in response to lipid overload.

5 April 2021 in Cells
Verified
Journal Article
Open access
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SQShuyang Qin
Shuyang Qin
AMAlexa D. Melucci
Alexa D. Melucci
Alexander ChaconAlexander Chacon
Alexander Chacon
PPPeter A. Prieto
Peter A. Prieto
Adoptive cell therapy (ACT) with tumor-infiltrating T cells (TILs) has emerged as a promising therapy for the treatment of unresectable or metastatic solid tumors. One challenge to finding a universal anticancer treatment is the heterogeneity present between different tumors as a result of genetic instability associated with tumorigenesis. As the epitome of personalized medicine, TIL-ACT bypasses the issue of intertumoral heterogeneity by utilizing the patient’s existing antitumor immune response. Despite being one of the few therapies capable of inducing durable, complete tumor regression, many patients fail to respond. Recent research has focused on increasing therapeutic efficacy by refining various aspects of the TIL protocol, which includes the isolation, ex vivo expansion, and subsequent infusion of tumor specific lymphocytes. This review will explore how the therapy has evolved with time by highlighting various resistance mechanisms to TIL therapy and the novel strategies to overcome them.

26 September 2022 in Journal of Pediatric Surgery
Verified
Journal Article
Closed access
EMElaa Mahdi
Elaa Mahdi
NTNicole Toscano
Nicole Toscano
LPLauren Pierson
Lauren Pierson
ENEric Ndikumana
Eric Ndikumana
BABrian Ayers
Brian Ayers
DWDerek Wakeman
Derek Wakeman

1 February 2017 in Annals of Medicine & Surgery
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Journal Article
Open access
SCShaun Colburn
Shaun Colburn
KCKurtis W. Childers
Kurtis W. Childers
Alexander ChaconAlexander Chacon
Alexander Chacon
ASAlexa Swailes
Alexa Swailes
FAFauzan M. Ahmed
Fauzan M. Ahmed
RSRajinder Sahi
Rajinder Sahi
Anabolic-androgenic steroid (AAS) use and testosterone therapy have been well established risk factors for the creation of a pro-thrombotic state, and to precipitate formation of thromboemboli in individuals already predisposed to thrombosis. Here, we present the case of an amateur bodybuilder, with a negative thrombophilia workup, who experienced primary renal infarction while using the AAS trenbolone acetate and testosterone, as well as a subsequent renal infarction while anticoagulated with apixaban. The development of subsequent infarctions in an anticoagulated patient with discontinued recreational steroid use poses a unique situation and challenges the current understanding of a thrombophilic state associated with steroids. The lifetime prevalence of anabolic steroid use is estimated to be 1% in the male population in the United States which is significant. Further understanding and recommendations of appropriate anticoagulant should be further elucidated to appropriately medically manage patients from this confounding social and medical history.

Verified
Journal Article
Open access
PDF file
Alexander ChaconAlexander Chacon
Alexander Chacon
AMAlexa D. Melucci
Alexa D. Melucci
SQShuyang Qin
Shuyang Qin
PPPeter A. Prieto
Peter A. Prieto
Metastatic melanoma remains the deadliest form of skin cancer. Immune checkpoint inhibition (ICI) immunotherapy has defined a new age in melanoma treatment, but responses remain inconsistent and some patients develop treatment resistance. The myriad of newly developed small molecular (SM) inhibitors of specific effector targets now affords a plethora of opportunities to increase therapeutic responses, even in resistant melanoma. In this review, we will discuss the multitude of SM classes currently under investigation, current and prospective clinical combinations of ICI and SM therapies, and their potential for synergism in melanoma eradication based on established mechanisms of immunotherapy resistance.

11 May 2021 in Cancers
Verified
Journal Article
Open access
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SQShuyang Qin
Shuyang Qin
BHBooyeon J. Han
Booyeon J. Han
AWAlyssa Williams
Alyssa Williams
KJKatherine Jackson
Katherine Jackson
RJRachel Jewell
Rachel Jewell
PPPeter A. Prieto
Peter A. Prieto
Metastatic melanoma portends a poor prognosis and patients may present with multiple, simultaneous tumors. Despite recent advances in systemic immunotherapy, a majority of patients fail to respond, or exhibit lesion-specific responses wherein some metastases respond as others progress within the same patient. While intertumoral heterogeneity has been clinically associated with these mixed lesion-specific therapeutic responses, no clear mechanism has been identified, largely due to the scarcity of preclinical models. We developed a novel murine synchronous melanoma model that recapitulates this intertumoral genetic and microenvironmental heterogeneity. We show that genetic differences between tumors are sufficient to generate distinct tumor immune microenvironments (TIME) simultaneously in the same mouse. Furthermore, these TIMEs lead to the independent regulation of PD-1/PD-L1 (programmed cell death protein 1/PD-1 ligand), a popular axis targeted by immune checkpoint therapy, in response to ongoing anti-tumor immunity and the presence of interferon-gamma. Currently, therapeutic selection for metastatic melanoma patients is guided by a single biopsy, which may not represent the immune status of all tumors. As a result, patients can display heterogeneous lesion-specific responses. Further investigations into this synchronous melanoma model will provide mechanistic insight into the effects of intertumoral heterogeneity and guide therapeutic selection in this challenging patient population.