Mutant p53 partners in crime Kim, Michael P; Lozano, Guillermina
Cell death and differentiation,
01/2018, Letnik:
25, Številka:
1
Journal Article
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Mutant p53 proteins impart changes in cellular behavior and function through interactions with proteins that alter gene expression. The milieu of intracellular proteins available to interact with ...mutant p53 is context specific and changes with disease, cell type, and environmental conditions. Varying conformations of mutant p53 largely dictate protein-protein interactions as different point mutations within protein-coding regions greatly alter the extent and array of gain-of-function (GOF) activities. Given such variables, how can knowledge regarding p53 missense mutations be translated into predicting or altering biologic activity for therapy? How may knowledge regarding mutant p53 functions within certain disease contexts be harnessed to blunt or ablate mutant p53 GOF for therapy? In this article, we review known proteins that interact with mutant p53 and result in the activation of genes that contribute to p53 GOF with particular emphasis on context dependency and an evolving appreciation of GOF mechanisms.
Poor central nervous system penetration of cytotoxic drugs due to the blood brain barrier (BBB) is a major limiting factor in the treatment of brain tumors. Most recurrent glioblastomas (GBM) occur ...within the peritumoral region. In this study, we describe a hyperthemic method to induce temporary disruption of the peritumoral BBB that can potentially be used to enhance drug delivery.
Twenty patients with probable recurrent GBM were enrolled in this study. Fourteen patients were evaluable. MRI-guided laser interstitial thermal therapy was applied to achieve both tumor cytoreduction and disruption of the peritumoral BBB. To determine the degree and timing of peritumoral BBB disruption, dynamic contrast-enhancement brain MRI was used to calculate the vascular transfer constant (Ktrans) in the peritumoral region as direct measures of BBB permeability before and after laser ablation. Serum levels of brain-specific enolase, also known as neuron-specific enolase, were also measured and used as an independent quantification of BBB disruption.
In all 14 evaluable patients, Ktrans levels peaked immediately post laser ablation, followed by a gradual decline over the following 4 weeks. Serum BSE concentrations increased shortly after laser ablation and peaked in 1-3 weeks before decreasing to baseline by 6 weeks.
The data from our pilot research support that disruption of the peritumoral BBB was induced by hyperthemia with the peak of high permeability occurring within 1-2 weeks after laser ablation and resolving by 4-6 weeks. This provides a therapeutic window of opportunity during which delivery of BBB-impermeant therapeutic agents may be enhanced.
ClinicalTrials.gov NCT01851733.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Most patients diagnosed with resected pancreatic adenocarcinoma (PDAC) survive less than 5 years, but a minor subset survives longer. Here, we dissect the role of the tumor microbiota and the immune ...system in influencing long-term survival. Using 16S rRNA gene sequencing, we analyzed the tumor microbiome composition in PDAC patients with short-term survival (STS) and long-term survival (LTS). We found higher alpha-diversity in the tumor microbiome of LTS patients and identified an intra-tumoral microbiome signature (Pseudoxanthomonas-Streptomyces-Saccharopolyspora-Bacillus clausii) highly predictive of long-term survivorship in both discovery and validation cohorts. Through human-into-mice fecal microbiota transplantation (FMT) experiments from STS, LTS, or control donors, we were able to differentially modulate the tumor microbiome and affect tumor growth as well as tumor immune infiltration. Our study demonstrates that PDAC microbiome composition, which cross-talks to the gut microbiome, influences the host immune response and natural history of the disease.
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•PDAC long-term survivors display high tumor microbial diversity and immunoactivation•A PDAC tumoral microbiome signature predicts PDAC long-term survival•The gut microbiome modulates the PDAC tumor microbiome landscape•Fecal microbial transplants can modulate tumors immunosuppression and growth
The distinct tumor microbiome from pancreatic cancer long-term survivors can be used to predict PDAC survival in humans, and transfer of long-term survivor gut microbiomes can alter the tumor microbiome and tumor growth in mouse models.
The gold-standard approaches for gleaning statistically valid conclusions from data involve random sampling from the population. Collecting properly randomized data, however, can be challenging, so ...modern statistical methods, including propensity score reweighting, aim to enable valid inferences when random sampling is not feasible. We put forth an approach for making inferences based on available data from a source population that may differ in composition in unknown ways from an eventual target population. Whereas propensity scoring requires a separate estimation procedure for each different target population, we show how to build a single estimator, based on source data alone, that allows for efficient and accurate estimates on any downstream target data. We demonstrate, theoretically and empirically, that our target-independent approach to inference, which we dub "universal adaptability," is competitive with target-specific approaches that rely on propensity scoring. Our approach builds on a surprising connection between the problem of inferences in unspecified target populations and the multicalibration problem, studied in the burgeoning field of algorithmic fairness. We show how the multicalibration framework can be employed to yield valid inferences from a single source population across a diverse set of target populations.
Multiple studies in recent years have identified highly tumorigenic populations of cells that drive tumor formation. These cancer stem cells (CSCs), or tumor-initiating cells (TICs), exhibit ...properties of normal stem cells and are associated with resistance to current therapies. As pancreatic adenocarcinoma is among the most resistant human cancers to chemo-radiation therapy, we sought to evaluate the presence of cell populations with tumor-initiating capacities in human pancreatic tumors. Understanding which pancreatic cancer cell populations possess tumor-initiating capabilities is critical to characterizing and understanding the biology of pancreatic CSCs towards therapeutic ends.
We have isolated populations of cells with high ALDH activity (ALDH(high)) and/or CD133 cell surface expression from human xenograft tumors established from multiple patient tumors with pancreatic adenocarcinoma (direct xenograft tumors) and from the pancreatic cancer cell line L3.6pl. Through fluorescent activated cell sorting (FACs)-mediated enrichment and depletion of selected pancreatic cancer cell populations, we sought to discriminate the relative tumorigenicity of cell populations that express the pancreatic CSC markers CD133 and aldehyde dehydrogenase (ALDH). ALDH(high) and ALDH(low) cell populations were further examined for co-expression of CD44 and/or CD24. We demonstrate that unlike cell populations demonstrating low ALDH activity, as few as 100 cells enriched for high ALDH activity were capable of tumor formation, irrespective of CD133 expression. In direct xenograft tumors, the proportions of total tumor cells expressing ALDH and/or CD133 in xenograft tumors were unchanged through a minimum of two passages. We further demonstrate that ALDH expression among patients with pancreatic adenocarcinoma is heterogeneous, but the expression is constant in serial generations of individual direct xenograft tumors established from bulk human pancreatic tumors in NOD/SCID mice.
We conclude that, in contrast to some previous studies, cell populations enriched for high ALDH activity alone are sufficient for efficient tumor-initiation with enhanced tumorigenic potential relative to CD133(+) and ALDH(low) cell populations in some direct xenograft tumors. Although cell populations enriched for CD133 expression may alone possess tumorigenic potential, they are significantly less tumorigenic than ALDH(high) cell populations. ALDH(high)/CD44(+)/CD24(+) or ALDH(low)/CD44(+)/CD24(+) phenotypes do not appear to significantly contribute to tumor formation at low numbers of inoculated tumor cells. ALDH expression broadly varies among patients with pancreatic adenocarcinoma and the apparent expression is recapitulated in serial generations of direct xenograft tumors in NOD/SCID. We have thus identified a distinct population of TICs that should lead to identification of novel targets for pancreatic cancer therapy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Adaptive fear responses to external threats rely upon efficient relay of computations underlying contextual encoding to subcortical circuits. Brain-wide analysis of highly coactivated ensembles ...following contextual fear discrimination identified the dorsolateral septum (DLS) as a relay of the dentate gyrus-CA3 circuit. Retrograde monosynaptic tracing and electrophysiological whole-cell recordings demonstrated that DLS somatostatin-expressing interneurons (SST-INs) receive direct CA3 inputs. Longitudinal in vivo calcium imaging of DLS SST-INs in awake, behaving mice identified a stable population of footshock-responsive SST-INs during contextual conditioning whose activity tracked and predicted non-freezing epochs during subsequent recall in the training context but not in a similar, neutral context or open field. Optogenetic attenuation or stimulation of DLS SST-INs bidirectionally modulated conditioned fear responses and recruited proximal and distal subcortical targets. Together, these observations suggest a role for a potentially hard-wired DLS SST-IN subpopulation as arbiters of mobility that calibrate context-appropriate behavioral fear responses.
Vitamin D has a pivotal role in regulating immune responses by promoting Th2 immune responses and suppressing Th1 responses. Propensities to a Th1 immune response and increased NK‐cell levels and ...cytotoxicity have been reported in women with recurrent pregnancy losses (RPL). In women with RPL, vitamin D deficiency is prevalent; however, the effect of vitamin D on NK cells is largely unknown. In this study, we demonstrated that CD69+ activating receptor expression on NK cells was significantly decreased by incubation with 1,25(OH)2D3 in a dose‐dependent manner, while CD158a and CD158b inhibitory receptor expression was upregulated. The degranulation marker CD107a was significantly downregulated on NK cells following incubation with 1,25(OH)2D3. NK‐cell conjugation with K562 target cells was not affected by 1,25(OH)2D3; however, depolarization of perforin granules in conjugated NK cells was significantly increased. TLR4 expression on NK cells was significantly decreased and TNF‐α and IFN‐γ production was significantly reduced by 1,25(OH)2D3 through interference with NF‐κB. Our results suggest 1,25(OH)2D3 has immune regulatory effects on NK cell cytotoxicity, cytokine secretion and degranulation process as well as TLR4 expression. Potential therapeutic application of 1,25(OH)2D3 for dysregulated NK‐cell immunity should be explored in the future.
Early detection of pancreatic ductal adenocarcinoma (PDAC) remains elusive. Precursor lesions of PDAC, specifically intraductal papillary mucinous neoplasms (IPMNs), represent a
pathway to invasive ...neoplasia, although the molecular correlates of progression remain to be fully elucidated. Single-cell transcriptomics provides a unique avenue for dissecting both the epithelial and microenvironmental heterogeneities that accompany multistep progression from noninvasive IPMNs to PDAC.
Single-cell RNA sequencing was performed through droplet-based sequencing on 5,403 cells from 2 low-grade IPMNs (LGD-IPMNs), 2 high-grade IPMNs (HGD-IPMN), and 2 PDACs (all surgically resected).
Analysis of single-cell transcriptomes revealed heterogeneous alterations within the epithelium and the tumor microenvironment during the progression of noninvasive dysplasia to invasive cancer. Although HGD-IPMNs expressed many core signaling pathways described in PDAC, LGD-IPMNs harbored subsets of single cells with a transcriptomic profile that overlapped with invasive cancer. Notably, a proinflammatory immune component was readily seen in low-grade IPMNs, composed of cytotoxic T cells, activated T-helper cells, and dendritic cells, which was progressively depleted during neoplastic progression, accompanied by infiltration of myeloid-derived suppressor cells. Finally, stromal myofibroblast populations were heterogeneous and acquired a previously described tumor-promoting and immune-evading phenotype during invasive carcinogenesis.
This study demonstrates the ability to perform high-resolution profiling of the transcriptomic changes that occur during multistep progression of cystic PDAC precursors to cancer. Notably, single-cell analysis provides an unparalleled insight into both the epithelial and microenvironmental heterogeneities that accompany early cancer pathogenesis and might be a useful substrate to identify targets for cancer interception.
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Orthostatic hypotension is defined as a decrease in blood pressure of 20 mm Hg or more systolic or 10 mm Hg or more diastolic within three minutes of standing from the supine position or on assuming ...a head-up position of at least 60 degrees during tilt table testing. Symptoms are due to inadequate physiologic compensation and organ hypoperfusion and include headache, lightheadedness, shoulder and neck pain (coat hanger syndrome), visual disturbances, dyspnea, and chest pain. Prevalence of orthostatic hypotension in the community setting is 20% in older adults and 5% in middle-aged adults. Risk factors such as diabetes mellitus increase the prevalence of orthostatic hypotension in all age groups. Orthostatic hypotension is associated with a significant increase in cardiovascular risk and falls, and up to a 50% increase in relative risk of all-cause mortality. Diagnosis is confirmed by performing a bedside simplified Schellong test, which consists of blood pressure and heart rate measurements after five minutes in the supine position and three minutes after moving to a standing position. If the patient is unable to stand safely or the clinical suspicion for orthostatic hypotension is high despite normal findings on the bedside test, head-up tilt table testing is recommended. Orthostatic hypotension is classified as neurogenic or nonneurogenic, depending on etiology and heart rate response. Treatment goals for orthostatic hypotension are reducing symptoms and improving quality of life. Initial treatment focuses on the underlying cause and adjusting potentially causative medications. Nonpharmacologic strategies include dietary modifications, compression garments, physical maneuvers, and avoiding environments that exacerbate symptoms. First-line medications include midodrine and droxidopa. Although fludrocortisone improves symptoms, it has concerning long-term effects.
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