Coumadin (R/S-warfarin) is a highly efficacious and widely used anticoagulant; however, its highly variable metabolism remains an important contributor to uncertainties in therapeutic responses. Pharmacogenetic studies report conflicting findings on the clinical relevance of CYP2C19. A resolution to this controversy is impeded by a lack of detail on the potential role of CYP2C19 in warfarin metabolism. Consequently, we assessed the efficiency of CYP2C19 metabolism of R- and S-warfarin and explored possible contributions in the liver using in vitro methods. Recombinant CYP2C19 metabolized R- and S-warfarin mainly to 6-, 7-, and 8-hydroxywarfarin, while 4′-hydroxywarfarin was a minor metabolite. Overall R-warfarin metabolism was slightly more efficient than that for S-warfarin. Metabolic pathways that produce R-6-, 7-, and 8-hydroxywarfarin in human liver microsomal reactions correlated strongly with CYP2C19 S-mephenytoin hydroxylase activity. Similarly, CYP1A2 activity toward phenacetin correlated with formation of R-6 and 7-hydroxywarfarin such that R-8-hydroxywarfarin seems unique to CYP2C19 and possibly a biomarker. In following, CYP2C19 likely impacts R-warfarin metabolism and patient response to therapy. Intriguingly, CYP2C19 may contribute to S-warfarin metabolism in patients, especially when CYP2C9 activity is compromised due to drug interactions or genetic polymorphisms.
Warfarin; CYP2C19; Cytochrome P450; metabolism; biomarker
Trisomy 14 mosaicism is a rare chromosomal abnormality with distinct and recognizable clinical features. We report a patient with presumed retinal dystrophy having diffuse retinal pigment epithelial abnormalities, which has not been previously reported in association with trisomy 14. This case expands the clinical spectrum of this rare entity.
Retinal dystrophies; Trisomy 14; Trisomy 14 mosaicism
Pancreatic cancer patients often have a poor prognosis and suffer from nutritional problems. Malnutrition is characterized by weight loss and decreased dietary intake, and is common among pancreatic cancer patients. The objective of this report was to describe the changes in dietary intake, body weight, nutritional status, and metabolic rate on a continuum from the time of diagnosis until the end of life in a patient with pancreatic cancer. In summary, the patient's nutritional status gradually declined, accompanied by extreme weight loss and decreased dietary intake. Conversely, resting energy expenditure, measured by indirect calorimetry, increased from 24 kcal/kg/day to 35 kcal/kg/day. Nutritional management during cancer treatment is important but may be challenging in pancreatic cancer patients.
Pancreatic cancer; Diet records; Nutritional status; Basal metabolism
Mineralocorticoid receptor antagonists (MRAs) improve outcomes in patients with heart failure and reduced left ventricular ejection fraction (HFrEF), but their use is limited by hyperkalaemia and/or worsening renal function (WRF). BAY 94-8862 is a highly selective and strongly potent non-steroidal MRA. We investigated its safety and tolerability in patients with HFrEF associated with mild or moderate chronic kidney disease (CKD).
Methods and results
This randomized, controlled, phase II trial consisted of two parts. In part A, the safety and tolerability of oral BAY 94-8862 [2.5, 5, or 10 mg once daily (q.d.)] was assessed in 65 patients with HFrEF and mild CKD. In part B, BAY 94-8862 (2.5, 5, or 10 mg q.d., or 5 mg twice daily) was compared with placebo and open-label spironolactone (25 or 50 mg/day) in 392 patients with HFrEF and moderate CKD. BAY 94-8862 was associated with significantly smaller mean increases in serum potassium concentration than spironolactone (0.04–0.30 and 0.45 mmol/L, respectively, P < 0.0001–0.0107) and lower incidences of hyperkalaemia (5.3 and 12.7%, respectively, P = 0.048) and WRF. BAY 94-8862 decreased the levels of B-type natriuretic peptide (BNP), amino-terminal proBNP, and albuminuria at least as much as spironolactone. Adverse events related to BAY 94-8862 were infrequent and mostly mild.
In patients with HFrEF and moderate CKD, BAY 94-8862 5–10 mg/day was at least as effective as spironolactone 25 or 50 mg/day in decreasing biomarkers of haemodynamic stress, but it was associated with lower incidences of hyperkalaemia and WRF.
Aldosterone; Antagonist; Chronic kidney disease; Heart failure; Mineralocorticoid receptor
To describe the ophthalmoscopic features and natural history in a case series of eyes that developed intraocular hemorrhages associated with perinatal distress and to evaluate their clinical courses.
A retrospective chart review of 289 neonates with a medical history of perinatal distress was conducted. Among these 289 patients (578 eyes), 29 eyes of 17 neonates were found to have had retinal hemorrhages or vitreous hemorrhages (VH). A comprehensive chart review, including details of fundoscopic findings and perinatal history, was conducted.
Intraocular hemorrhage was present in 5.5% of the patients. Most hemorrhages (82.7%) were intraretinal. In our population, 17% (n = 5) of hemorrhages resolved within two weeks, but 31% (n = 9) did not resolve even after four weeks. Most hemorrhages spontaneously resolved without any specific sequelae; however, one infant's dense unilateral VH persisted up to three months after birth. When the patient was seen again at 3.5 years of age, she had developed axial myopia and severe amblyopia of the involved eye.
In asphyxiated newborns, the possibility of intraocular hemorrhages should be considered. Long-standing, dense hemorrhages obscuring the macula may lead to severe vision deprivation amblyopia. Therefore, ophthalmic examination should be considered in neonates with perinatal distress, and close observation is necessary for hemorrhages that do not resolve in this amblyogenic age group.
Newborn infant; Perinatal distress; Retinal hemorrhage; Vitreous hemorrhage
The number of cancer survivors is increasing dramatically. Many cancer survivors face lifetime risks associated with their cancer therapy, with a significant proportion at risk for serious morbidity and premature mortality. Concerns regarding the long-term physical, psychosocial, and economic effects of cancer treatment on cancer survivors and their families are increasingly being recognized and addressed by public and private sector. This article summarizes economic burden of cancer survivors, main post-treatment health problems including secondary primary cancer and comorbidities, health behaviors such as smoking, exercise and physical activity, nutrition, and psychosocial problems. Faced with various health and psychosocial problems specific to this population, several healthcare and policy models are being suggested to address these issues, including 'shared care model' and 'integrative supportive care service delivery system for cancer survivors'. More effort is needed to make the cancer survivorship agenda a reality, attended by a wide variety of stakeholders including researchers, patients, providers, and policy makers.
Cancer; Survivors; Second Primary Neoplasm; Korea
The PI3K signaling pathway regulates diverse cellular processes, including proliferation, survival, and metabolism, and is aberrantly activated in human cancer. As such, numerous compounds targeting the PI3K pathway are currently being clinically evaluated for the treatment of cancer, and several have shown some early indications of efficacy in breast cancer. However, resistance against these agents, both de novo and acquired, may ultimately limit the efficacy of these compounds. Here, we have taken a systematic functional approach to uncovering potential mechanisms of resistance to PI3K inhibitors and have identified several genes whose expression promotes survival under conditions of PI3K/mammalian target of rapamycin (PI3K/mTOR) blockade, including the ribosomal S6 kinases RPS6KA2 (RSK3) and RPS6KA6 (RSK4). We demonstrate that overexpression of RSK3 or RSK4 supports proliferation upon PI3K inhibition both in vitro and in vivo, in part through the attenuation of the apoptotic response and upregulation of protein translation. Notably, the addition of MEK- or RSK-specific inhibitors can overcome these resistance phenotypes, both in breast cancer cell lines and patient-derived xenograft models with elevated levels of RSK activity. These observations provide a strong rationale for the combined use of RSK and PI3K pathway inhibitors to elicit favorable responses in breast cancer patients with activated RSK.
To describe the prevalence of suicidal ideation and suicide attempts in family caregivers (FCs) of patients with cancer and to identify the factors associated with suicidal ideation and suicide attempts in FCs with anxiety or depression.
A national, multicenter survey administered to 897 FCs asked questions concerning suicidal ideation and suicide attempts during the previous year and assessed anxiety, depression, socio–demographic factors, caregiving burden, patient factors, and quality of life (QOL).
A total of 17.7% FCs reported suicidal ideation, and 2.8% had attempted suicide during the previous year. Among FCs with anxiety, 31.9% had suicidal ideation and 4.7% attempted suicide; the corresponding values for FCs with depression were 20.4% and 3.3%, respectively. Compared with FCs without anxiety and depression, FCs with anxiety or depression showed a higher adjusted odds ratios (aOR) for suicidal ideation (aOR = 4.07 and 1.93, respectively) and attempts (OR = 3.00 and 2.43, respectively). Among FCs with anxiety or depression, being female, unmarried, unemployed during caregiving, and having a low QOL were associated with increased odds of suicidal ideation. FCs with anxiety who became unemployed during caregiving constituted a high-risk group for suicide. Being unmarried and having a low QOL with respect to financial matters were associated with increased suicide attempts among FCs with depression.
FCs with anxiety or depression were at high risk of suicide. Interventions to enhance social support and to improve perceived QOL may help prevent suicide and manage suicidal ideation in FCs with anxiety or depression.
A 61-year-old man with no history of malignancy presented with a rapidly expanding left periorbital mass, first noticed one month prior to presentation. The mass was firm, and a pus-like discharge drained spontaneously from the center of the lesion. A biopsy was performed, and histopathology confirmed squamous cell carcinoma. Systemic evaluation revealed that the patient had a primary esophageal squamous cell carcinoma with multiple metastases. The prognosis of orbital metastasis is generally poor, and this patient expired after one month of conservative treatment.
Abscess; Orbital neoplasms; Squamous cell carcinoma
Cadmium(Cd), a heavy metal, which has a potent harmful effects, is a highly stress-inducible material that is robustly expressed following disruption of homeostasis in the endoplasmic reticulum (ER) (so-called ER stress). The mechanism Cd induced cell death of neuroblastoma cells complex, involving cellular signaling pathways as yet incompletely defined but, in part, involving the generation of reactive oxygen species (ROS). Several studies have correlated GADD153 expression with cell death, but a mechanistic link between GADD153 and apoptosis has never been demonstrated.
SH-SY5Y cells were treated Cd led to increase in intracellular ROS levels. ROS generation is not consistent with intracellular [Ca2+]. The exposure of neuroblastoma cells to Cd led to increase in intracellular GADD153 and Bak levels in a doses and time dependent manner. The induction of these genes by Cd was attenuated by NAC. Cd-induced apoptosis is decreased in GADD153 knockdown cells compared with normal cells. The effect of GADD153 on the binding of C/EBP to the Bak promoters were analyzed ChIP assay. Basal constitutive GADD153 recruitment to the –3,398/–3,380 region of the Bak promoter is observed in SH-SY5Y cells.
The exposure of SH-SY5Y cells to Cd led to increase in intracellular ROS levels in a doses and time dependent manner. The generation of ROS result in the induction of GADD153 is causative of cadmium-induced apoptosis. GADD153 regulates Bak expression by its binding to promoter region (between −3,398 and −3,380). Therefore, we conclude that GADD153 sensitizes cells to ROS through mechanisms that involve up-regulation of BAK and enhanced oxidant injury.
Cadmium; ROS; ER; Bak
Background. Although studies have shown that the use of complementary and alternative medicine (CAM) is common in cancer patients, few surveys have assessed CAM use and associated factors in various cancers in Korea. Objectives. We explored factors predicting CAM use among a nationally representative sample of cancer patients. Methods. In total, 2,661 cancer patients were administered questionnaires about their CAM use and factors that might predict CAM use including sociodemographics, clinical and quality-of-life factors, time since diagnosis, trust in physicians, trust in hospitals, satisfaction, and informational needs. Data were analyzed using Pearson's χ2
tests and multivariate logistic regression analysis. Results. Overall, 25.5% reported that they had used or were using CAM. Higher income, presence of metastasis, longer time since diagnosis, less trust in hospitals, lower overall satisfaction, and higher degree of informational need were significantly associated with CAM use. Conclusions. The use of CAM in patients with cancer can be interpreted as an attempt to explore all possible options, expression of an active coping style, or expression of unmet needs in the cancer care continuum. Physicians need to openly discuss the use of CAM with their patients and identify whether they have other unmet supportive needs.
While knowledge and risk perception have been associated with screening for second primary cancer (SPC), there are no clinically useful indicators to identify who is at risk of not being properly screened for SPC. We investigated whether the mode of primary cancer detection (i.e. screen-detected vs. non-screen-detected) is associated with subsequent completion of all appropriate SPC screening in cancer survivors.
Data were collected from cancer patients treated at the National Cancer Center and nine regional cancer centers across Korea. A total of 512 cancer survivors older than 40, time since diagnosis more than 2 years, and whose first primary cancer was not advanced or metastasized were selected. Multivariate logistic regression was used to examine factors, including mode of primary cancer detection, associated with completion of all appropriate SPC screening according to national cancer screening guidelines.
Being screen-detected for their first primary cancer was found to be significantly associated with completion of all appropriate SPC screening (adjusted odds ratio, 2.13; 95% confidence interval, 1.36–3.33), after controlling for demographic and clinical variables. Screen-detected cancer survivors were significantly more likely to have higher household income, have other comorbidities, and be within 5 years since diagnosis.
The mode of primary cancer detection, a readily available clinical information, can be used as an indicator for screening practice for SPC in cancer survivors. Education about the importance of SPC screening will be helpful particularly for cancer survivors whose primary cancer was not screen-detected.
Cancer survivor; Second primary cancer; Screening; Mode of detection; Screen-detected
Many laboratories use 4 delta check methods: delta difference, delta percent change, rate difference, and rate percent change. However, guidelines regarding decision criteria for selecting delta check methods have not yet been provided. We present new decision criteria for selecting delta check methods for each clinical chemistry test item.
We collected 811,920 and 669,750 paired (present and previous) test results for 27 clinical chemistry test items from inpatients and outpatients, respectively. We devised new decision criteria for the selection of delta check methods based on the ratio of the delta difference to the width of the reference range (DD/RR). Delta check methods based on these criteria were compared with those based on the CV% of the absolute delta difference (ADD) as well as those reported in 2 previous studies.
The delta check methods suggested by new decision criteria based on the DD/RR ratio corresponded well with those based on the CV% of the ADD except for only 2 items each in inpatients and outpatients. Delta check methods based on the DD/RR ratio also corresponded with those suggested in the 2 previous studies, except for 1 and 7 items in inpatients and outpatients, respectively.
The DD/RR method appears to yield more feasible and intuitive selection criteria and can easily explain changes in the results by reflecting both the biological variation of the test item and the clinical characteristics of patients in each laboratory. We suggest this as a measure to determine delta check methods.
Delta check; Detection methods; Reference range; Decision criteria
The aim of this study was to develop an appropriate nursing information guideline according to corrected age, after investigating parents' concerns about the growth, development, and diseases of their premature infants after discharge from the neonatal intensive care unit (NICU).
The parents of premature infants (birth weight, <2,500 g; gestational age, <37 weeks) who went to a neonatal follow-up clinic after NICU discharge at Seoul St. Mary's Hospital from January 2005 to December 2009, were asked with regard to their concerns about their infants through a questionnaire survey. The results of physical examinations, including body measurements and neurodevelopmental status at 4, 8, 12, and 18 months of corrected age, were retrospectively reviewed in 390 infants.
The most common parental concerns were developmental delay, poor growth, and feeding and nutritional problems. Parental concerns about developmental delay, growth failure in improvement in body weight and length, and overweightness were high in specificity but very low in sensitivity. After NICU discharge, 30% of premature infants experienced infectious diseases before 18 months of corrected age, the most common of which was respiratory tract infection.
For guiding of premature infants in outpatient day clinics after NICU discharge, it is necessary to identify the parents' highest concerns, to educate them about the possibilities of growth and neurodevelopmental disabilities in their infants and to provide them with handouts containing guidelines on the management of infectious diseases, especially respiratory infections.
Premature infant; Follow-up; Questionnaire; Guidance; Neonatal intensive care units
The purposes of this study were to determine phenolic compounds and to evaluate antioxidant activities of plums (Soldam, Oishiwase and Formosa). Soldam contains the highest amount of total phenolics among cultivars (Formosa: 4.0%, Oishiwase: 3.3%, Soldam: 6.4% for total phenolic) as well as the total flavonoids of which constituents were mainly myricetin and anthocyanidin. The antioxidant activities were measured by DPPH, ABTS radical scavenging, and SOD-like activities. The DPPH radical scavenging activity of Korean plum extracts (200 µg/mL) showed more than 43%, and the Soldam turned out to be the highest : ID50 value: 160-177 µg/mL for Formosa and Oishiwase; 58-64 µg/mL for Soldam. The ABTS radical scavenging activity of Korean plum extracts (200 µg/mL) was found to be more than 50%. The SOD-like activity of Korean plum extracts (200 µg/mL) showed more than 70%. Among three kinds of cultivars, Soldam had the highest antioxidant activity. The nitrite scavenging activity of Soldam was 61.5%, which is the highest, compared with that of the other cultivars, about 50%. From these results, Korean plums turned out to be phytochemical rich fruit as well as to show high antioxidant activities.
Antioxidant activity; phenolic compounds; oriental plums
Multiple treatment modalities, including topical and systemic corticosteroid and phototherapy, have been used in treatment of patients with atopic dermatitis. However, long-term corticosteroid therapy may have various adverse effects. The purpose of this study was to investigate the therapeutic efficacy and safety of bath therapy using green tea extracts for treatment of patients with atopic dermatitis. A total of four patients with atopic dermatitis were enrolled in this study. A Malassezia multiplex detection kit was used in performance of multiplex PCR on clinical isolates, which confirmed Malassezia sympodialis. Subjects underwent treatment with bath therapy using green tea extracts three times per wk for a period of 4 wk. Assessment using the scoring atopic dermatitis (SCORAD) index, the visual analogue scale for pruritus, and transepidermal water loss was performed weekly. Laboratory tests were performed before and after treatment. All patients showed marked improvement on the mean SCORAD and visual analogue scale, and a significant decrease in the mean values of serum eosinophil counts was observed after treatment. Bath therapy with green tea extract is an effective, safe, and nonsteroidal therapy for treatment of patients with atopic dermatitis associated with Malassezia sympodialis.
Atopic dermatitis; Bath therapy; Catechin; Green tea extract
Several common neuropsychiatric disorders (e.g., obsessive-compulsive disorder, Tourette syndrome (TS), autistic spectrum disorder) are associated with unpleasant bodily sensations that are perceived as an urge for action. Similarly, many of our everyday behaviors are also characterized by bodily sensations that we experience as urges for action. Where do these urges originate? In this paper, we consider the nature and the functional anatomy of “urges-for-action,” both in the context of everyday behaviors such as yawning, swallowing, and micturition, and in relation to clinical disorders in which the urge-for-action is considered pathological and substantially interferes with activities of daily living (e.g., TS). We review previous frameworks for thinking about behavioral urges and demonstrate that there is considerable overlap between the functional anatomy of urges associated with everyday behaviors such as swallowing, yawning, and micturition, and those urges associated with the generation of tics in TS. Specifically, we show that the limbic sensory and motor regions—insula and mid-cingulate cortex—are common to all of these behaviors, and we argue that this “motivation-for-action” network should be considered distinct from an “intentional action” network, associated with regions of premotor and parietal cortex, which may be responsible for the perception of “willed intention” during the execution of goal-directed actions.
Urge; Urge-for-action; Habit; Insula; Tourette syndrome; Action
The purpose of this study was to define a one-portion size of food frequently consumed by the Koreans aged 65 years or over. From the original 8,631 people who took part in the Forth Korea National Health and Nutrition Examination Survey (KNHANES IV-2) 2008, we analyzed the data on 1,458 persons (16.9%) aged 65 and over, and selected food items consumed based on the intake frequency of 30 or more by all participant. A total of 158 varieties of food items were selected. The portion size of food items was set on the basis of the median amount (50 percentile) in a single intake by a single person. In the cereals category, 13 items were selected, of which the most frequently consumed item was well-polished rice with portion size of 75 g. Among legumes, 7 items were selected, of which the most frequent item was dried black soybean with a portion size of 6 g. Among the 16 groups, the most varied food group (49 items) was vegetables, and among these the most frequently occurring item was garlic (5 g), while among the fruit group, only 11 items were selected, as their intake frequency was low. Fish and shellfish were more frequently consumed by the elderly than meats. The most frequently consumed meat was pork loin, with a portion size of 30 g. In fish and shellfish, the most frequently consumed item was dried and boiled large anchovy with a portion size of 2 g. Portion sizes for food items consumed regularly by the elderly may be conveniently and effectively used in dietary planning and in nutritional education programs, and in assessing the diet intake status of the elderly.
Portion size; Korean elderly; foods frequently consumed
A 47-day-old male infant presented with fever, poor oral intake, irritability, and right-sided bluish buccal swelling. Contrast-enhanced computed tomography of the neck showed a round mass lesion of about 2.0×1.5 cm that suggested abscess formation in the right masticator space. Ultrasound-guided extraoral aspiration of the abscess at the right masseter muscle was successful. Staphylococcus aureus was identified in the culture from the aspirated pus and blood. Appropriate antibiotics were given and the patient recovered. The patient underwent follow-up ultrasonography that showed an improved state of the previously observed right masseter muscle swelling at about 1 month after hospital discharge. A masticator space abscess usually originates from an odontogenic infection in adults. We report a case of masticator space abscess in a 47-day-old infant in whom septicemia without odontogenic infection was suspected.
Abscess; Infant; Bacteremia
Oncogenic mutations in the serine/threonine kinase B-RAF are found in 50–70% of malignant melanomas1. Pre-clinical studies have demonstrated that the B-RAFV600E mutation predicts a dependency on the mitogen activated protein kinase (MAPK) signaling cascade in melanoma1–5—an observation that has been validated by the success of RAF and MEK inhibitors in clinical trials6–8. However, clinical responses to targeted anticancer therapeutics are frequently confounded by de novo or acquired resistance9–11. Identification of resistance mechanisms in a manner that elucidates alternative ‘druggable’ targets may inform effective long-term treatment strategies12. Here, we expressed ~600 kinase and kinase-related open reading frames (ORFs) in parallel to functionally interrogate resistance to a selective RAF kinase inhibitor. We identified MAP3K8 (COT/TPL2) as a MAPK pathway agonist that drives resistance to RAF inhibition in B-RAFV600E cell lines. COT activates ERK primarily through MEK-dependent mechanisms that do not require RAF signaling. Moreover, COT expression is associated with de novo resistance in B-RAFV600E cultured cell lines and acquired resistance in melanoma cells and tissue obtained from relapsing patients following treatment with MEK or RAF inhibition. We further identify combinatorial MAPK pathway inhibition or targeting of COT kinase activity as possible therapeutic strategies for reducing MAPK pathway activation in this setting. Together, these results provide new insights into resistance mechanisms involving the MAPK pathway and articulate an integrative approach through which high-throughput functional screens may inform the development of novel therapeutic strategies.
Dysfunctional mTORC1 signaling is associated with a number of human pathologies owing to its central role in controlling cell growth, proliferation, and metabolism. Regulation of mTORC1 is achieved by the integration of multiple inputs, including those of mitogens, nutrients, and energy. It is thought that agents that increase the cellular AMP/ATP ratio, such as the anti-diabetic biguanides metformin and phenformin, inhibit mTORC1 through AMPK activation of TSC1/2-dependent or -independent mechanisms. Unexpectedly, we found that biguanides inhibit mTORC1 signaling, not only in the absence of TSC1/2, but also in the absence of AMPK. Consistent with these observations, in two distinct pre-clinical models of cancer and diabetes, metformin acts to suppress mTORC1 signaling in an AMPK-independent manner. We found that the ability of biguanides to inhibit mTORC1 activation and signaling is, instead, dependent on the Rag GTPases.
An extreme diversity of substrates and catalytic reactions of cytochrome P450 (P450) enzymes is considered to be the consequence of evolutionary adaptation driven by different metabolic or environmental demands. Here we report the presence of numerous natural variants of P450 BM3 (CYP102A1) within a species of Bacillus megaterium. Extensive amino acid substitutions (up to 5% of the total 1049 amino acid residues) were identified from the variants. Phylogenetic analyses suggest that this P450 gene evolve more rapidly than the rRNA gene locus. It was found that key catalytic residues in the substrate channel and active site are retained. Although there were no apparent variations in hydroxylation activity towards myristic acid (C14) and palmitic acid (C16), the hydroxylation rates of lauric acid (C12) by the variants varied in the range of >25-fold. Interestingly, catalytic activities of the variants are promiscuous towards non-natural substrates including human P450 substrates. It can be suggested that CYP102A1 variants can acquire new catalytic activities through site-specific mutations distal to the active site.
We previously reported two modes of development of acquired TRAIL resistance: early phase and late phase . In these studies, we observed that greater Akt activity and the expression of Bcl-xL were related mainly to the late phase of acquired TRAIL resistance.
Recently we became aware of a possible mechanism of early phase TRAIL resistance development through internalization and degradation of TRAIL receptors (DR4 and DR5). Our current studies demonstrate that TRAIL receptors rapidly diminish at the membrane as well as the cytoplasm within four hours after TRAIL exposure, but recover completely after one or two days. Our studies also reveal that Cbl, a ubiquitously expressed cytoplasmic adaptor protein, is responsible for the rapid degradation of TRAIL receptors; Cbl binds to them and induces mono-ubiquitination of these receptors concurrent with their degeneration soon after TRAIL exposure, creating the early phase of acquired TRAIL resistance.
c-Cbl; TRAIL; TRAIL receptors; TRAIL resistance