Clinicopathological Significance of Papillary Thyroid Carcinoma Located in the Isthmus: A Meta-Analysis.

BACKGROUND: The thyroid isthmus is located directly anterior to the trachea and is covered by the strap muscles. Several studies have suggested that papillary thyroid carcinoma (PTC) in the isthmus is more aggressive and is associated with a poor prognosis. The purpose of this meta-analysis was to assess the clinicopathological characteristics and recurrence rates of PTC in the isthmus compared to PTC at other sites. METHODS: Relevant articles were obtained by searching the PubMed database. A meta-analysis was performed using 11 eligible studies. RESULTS: The rate of extrathyroidal extension was 0.502 (95% confidence interval [CI]: 0.239-0.764) and 0.454 (95% CI: 0.331-0.582) for isthmus PTC and PTC at other site, respectively; however, the difference in the rates was not statistically significant. Lymphovascular invasion did not significantly differ between isthmus PTC (0.179 [95% CI: 0.102-0.297]) and PTC at other sites (0.114 [95% CI: 0.066-0.188]). The rate of central lymph node (LN) metastasis was significantly higher in isthmus PTC (0.527 [95% CI: 0.435-0.617]) than in PTC at other sites (0.352 [95% CI: 0.280-0.432]). No significant difference was observed between the two groups in terms of lateral cervical LN metastasis rate. Isthmus PTC was more likely to have a prominent recurrence rate (0.046 [95% CI: 0.022-0.094]) than PTC at other sites (0.010 [95% CI: 0.001-0.070]); however, the difference was not statistically significant (because of the small number of included studies). CONCLUSIONS: The results of this meta-analysis indicated that isthmus PTC was associated with an increased risk of central LN metastasis. Isthmus PTC seems to have a slightly higher recurrence rate than PTC at other sites. Therefore, considering the potential of the isthmus location as an unfavorable factor, more attention should be focused on isthmus PTC, and a more aggressive approach such as prophylactic central LN dissection might provide better outcomes in PTC management.

Prevalence of fluoroquinolone-resistant rectal flora in patients undergoing transrectal ultrasound-guided prostate needle biopsy: A prospective multicenter study.

OBJECTIVES: To estimate the prevalence of fluoroquinolone-resistant rectal flora in patients undergoing transrectal ultrasound-guided prostate needle biopsy and to identify the high-risk groups. METHODS: From January 2015 to March 2016, rectal swabs of 557 men who underwent transrectal ultrasound-guided prostate needle biopsy were obtained from five institutions. Clinical variables, including demographics, rectal swab culture results and infectious complications, were evaluated. Univariable and multivariable analyses were used to identify the risk factors for fluoroquinolone resistance of rectal flora and infectious complications. RESULTS: The incidence of fluoroquinolone-resistant and extended-spectrum beta-lactamase production was 48.1 and 11.8%, respectively. The most common fluoroquinolone-resistant bacteria was Escherichia coli (81% of total fluoroquinolone-resistant bacteria, 39% of total rectal flora), and 16 (2.9%) patients had infectious complications. Univariable and multivariable analysis of clinical parameters affecting fluoroquinolone resistance showed no factor associated with fluoroquinolone resistance of rectal flora. The clinical parameter related to infectious complications after prostate biopsy was a history of operation within 6 months (relative risk 6.60; 95% confidence interval 1.99-21.8, P = 0.002). CONCLUSIONS: These findings suggest that a risk-based approach by history taking cannot predict antibiotic resistance of rectal flora, and physicians should consider targeted antibiotic prophylaxis or extended antibiotic prophylaxis for Korean patients undergoing transrectal ultrasound-guided prostate biopsy because of high antibiotic resistance of rectal flora.

Clinicopathological Significance and Prognosis of Medullary Thyroid Microcarcinoma: A Meta-analysis.

BACKGROUND: The objective of the present meta-analysis was to evaluate the clinicopathological significance and prognosis of micro-MTC compared to macro-MTC. METHODS: Relevant articles were obtained by searching the PubMed and MEDLINE databases. A meta-analysis was performed using 15 eligible studies. In addition, subgroup analysis based on heredity was performed in patients diagnosed with micro-MTC. RESULTS: The rate of extrathyroidal extension of micro-MTC [0.118 (95% CI 0.073-0.185)] was significantly lower than that of macro-MTC [0.303 (95% CI 0.224-0.395)]. Micro-MTC [0.229 (95% CI 0.161-0.314)] had a significantly lower rate of cervical lymph node (LN) metastasis compared to macro-MTC [0.595 (95% CI 0.486-0.694)]. The rate of multifocality was not significantly different between micro-MTC and macro-MTC [0.394 (95% CI 0.244-0.566) vs. 0.320 (95% CI 0.234-0.421), respectively]. The rate of distant metastasis did not differ significantly between micro-MTC [0.082 (95% CI 0.017-0.314)] and macro-MTC [0.068 (95% CI 0.009-0.376)]. Patients with micro-MTC showed significantly higher disease-free survival rates [hazard ratio [HR] 0.406 (95% CI 0.288-0.575), I 2 = 40.563%] compared to patients with macro-MTC. CONCLUSION: Micro-MTC has aggressive features, such as multifocality and distant metastasis, similar to macro-MTC and a non-negligible rate of extrathyroidal extension and cervical LN metastasis. We suggest that treatment of micro-MTC should be approached with a similar focus as that of macro-MTC. Considering that less extrathyroidal extension and cervical LN metastasis occur in patients with micro-MTC compared to macro-MTC, we propose that treatment of micro-MTC, which has a relatively low disease burden status, should be viewed as an opportunity for improving prognosis.

Mean Platelet Volume, Platelet Distribution Width, and Platelet Count in Varicocele: A Systematic Review and Meta-Analysis.

BACKGROUND/AIMS: The aim of this study was to elucidate the usefulness of platelet indices, mean platelet volume (MPV), platelet distribution width (PDW), and platelet count in diagnosis and monitoring of varicocele. METHODS: The current study included 525 patients and 379 healthy subjects from five eligible studies. We performed meta-analysis of MPV, PDW, and platelet count and mean differences in these platelet indices between healthy subjects and varicocele patients. RESULTS: The pooled MPVs were 8.168 fL (95% confidence interval [CI] 7.589 to 8.747) and 8.801 fL (95% CI 8.028 to 9.574) in healthy subjects and varicocele patients, respectively. The pooled mean difference in MPV between healthy subjects and varicocele patients was 0.834 fL in case-control studies (95% CI 0.195 to 1.473, P = 0.011). In both healthy subjects and varicocele patients, low platelet count subgroups showed higher MPV than high platelet count subgroups. The mean difference in MPV was higher in low platelet count subgroup. There was no significant difference in PDW between healthy subjects and varicocele patients. CONCLUSION: Taken together, our data showed that platelet count was significantly lower in varicocele patients than in healthy subjects. Varicocele patients showed significantly higher MPV and lower platelet count than healthy subjects. MPV levels of patients differed according to platelet counts.

Systematic Review and Meta-Analysis of Intravesical Hyaluronic Acid and Hyaluronic Acid/Chondroitin Sulfate Instillation for Interstitial Cystitis/Painful Bladder Syndrome.

BACKGROUND/AIMS: To assess the efficacy of intravesical hyaluronic acid (HA) and HA/chondroitin sulfate (CS) instillation in patients with interstitial cystitis/painful bladder syndrome by systematic review and meta-analysis. METHODS: A systematic literature search was performed using the keywords: 'interstitial cystitis' or 'painful bladder syndrome' or 'bladder pain syndrome' and 'hyaluronic acid', up to March 31, 2016. The primary outcome was visual analogue scale related pain symptom (VAS). Secondary outcomes were the O'Leary-Sant Interstitial Cystitis Symptom Index (ICSI) and Problem Index (ICPI), frequency, nocturia, bladder volume, and voided urine volume. RESULTS: Ten articles involving 390 patients were retrieved and assessed in analysis. A significant improvement in mean VAS on fixed-effect and random-effect models (mean difference [MD] -3.654, 95% confidence interval [CI] -3.814 to -3.495, and MD -3.206, 95% CI -4.156 to -2.257, respectively) was found. Significant improvements were found in the ICSI (MD -3.223, 95% CI -4.132 to -2.315) and ICPI (MD -2.941, 95% CI -3.767 to -2.116). Similarly, the other outcomes were significantly improved. CONCLUSION: Intravesical HA and HA/CS instillation improved pain symptom, quality of life, and other outcomes and could be included as therapeutic modality of interstitial cystitis/painful bladder syndrome.

Gene expression analysis of bone metastasis and circulating tumor cells from metastatic castrate-resistant prostate cancer patients.

BACKGROUND: Characterization of genes linked to bone metastasis is critical for identification of novel prognostic or predictive biomarkers and potential therapeutic targets in metastatic castrate-resistant prostate cancer (mCRPC). Although bone marrow core biopsies (BMBx) can be obtained for gene profiling, the procedure itself is invasive and uncommon practice in mCRPC patients. Conversely, circulating tumor cells (CTCs), which are likely to stem from bone metastases, can be isolated from blood. The goals of this exploratory study were to establish a sensitive methodology to analyze gene expression in BMBx and CTCs, and to determine whether the presence or absence of detectable gene expression is concordant in matching samples from mCRPC patients. METHODS: The CellSearch(®) platform was used to enrich and enumerate CTCs. Low numbers of PC3 prostate cancer (PCa) cells were spiked into normal blood to assess cell recovery rate. RNA extracted from recovered PC3 cells was amplified using an Eberwine-based procedure to obtain antisense mRNA (aRNA), and assess the linearity of the RNA amplification method. In this pilot study, RNAs extracted from CTCs and PCa cells microdissected from formalin-fixed paraffin-embedded BMBx, were amplified to obtain aRNA and assess the expression of eight genes functionally relevant to PCa bone metastasis using RT-PCR. RESULTS: RNAs were successfully extracted from as few as 1-5 PCa cells in blood samples. The relative expression levels of reference genes were maintained after RNA amplification. The integrity of the amplified RNA was also demonstrated by RT-PCR analysis using primer sets that target the 5'-end, middle, and 3'-end of reference mRNA. We found that in 21 out of 28 comparisons, the presence or absence of detectable gene expression in CTCs and PCa cells microdissected from single bone lesions of the same patients was concordant. CONCLUSIONS: This exploratory analysis suggests that aRNA amplification through in vitro transcription may be useful as a method to detect gene expression in small numbers of CTCs and tumor cells microdissected from bone metastatic lesions. In some cases, gene expression in CTCs and BMBxs was not concordant, raising questions about using CTC gene expression to make clinical decisions.

Bone-induced c-kit expression in prostate cancer: a driver of intraosseous tumor growth.

Loss of BRCA2 function stimulates prostate cancer (PCa) cell invasion and is associated with more aggressive and metastatic tumors in PCa patients. Concurrently, the receptor tyrosine kinase c-kit is highly expressed in skeletal metastases of PCa patients and induced in PCa cells placed into the bone microenvironment in experimental models. However, the precise requirement of c-kit for intraosseous growth of PCa and its relation to BRCA2 expression remain unexplored. Here, we show that c-kit expression promotes migration and invasion of PCa cells. Alongside, we found that c-kit expression in PCa cells parallels BRCA2 downregulation. Gene rescue experiments with human BRCA2 transgene in c-kit-transfected PCa cells resulted in reduction of c-kit protein expression and migration and invasion, suggesting a functional significance of BRCA2 downregulation by c-kit. The inverse association between c-kit and BRCA2 gene expressions in PCa cells was confirmed using laser capture microdissection in experimental intraosseous tumors and bone metastases of PCa patients. Inhibition of bone-induced c-kit expression in PCa cells transduced with lentiviral short hairpin RNA reduced intraosseous tumor incidence and growth. Overall, our results provide evidence of a novel pathway that links bone-induced c-kit expression in PCa cells to BRCA2 downregulation and supports bone metastasis.

Efficacy and safety of augmentation ileocystoplasty combined with supratrigonal cystectomy for the treatment of refractory bladder pain syndrome/interstitial cystitis with Hunner's lesion.

OBJECTIVE: To evaluate the efficacy and safety of augmentation ileocystoplasty with supratrigonal cystectomy for the treatment of refractory bladder pain syndrome/interstitial cystitis patients with Hunner's lesion. METHODS: Of 45 patients who underwent augmentation ileocystoplasty with supratrigonal cystectomy between July 2006 and June 2012, 40 patients (33 women, 7 men) were included in the analysis. Primary outcome was the change in the O'Leary-Sant interstitial cystitis symptoms/problem index from baseline to 1, 3 and 6 months. Changes in pain, urgency, frequency, functional bladder capacity and maximal cystometric capacity were also assessed. Intraoperative and postoperative complications were evaluated. RESULTS: Median preoperative symptom duration was 5.0 years (range 3.0-6.0 years). Pain decreased significantly after surgery (8.3 vs. 1.3, P < 0.001). Functional bladder capacity and maximal cystometric capacity increased, whereas frequency, urgency and nocturia decreased significantly after surgery (all P < 0.001). At 6 months, significant improvements in the interstitial cystitis symptom index (17.8 vs. 9.9, P < 0.001) and interstitial cystitis problem index (14.6 vs. 6.5, P < 0.001) compared with baseline were noted. Seven patients developed vesicoureteral reflux and seven patients had acute pyelonephritis that resolved with antibiotic treatment. Five patients required clean intermittent self-catheterization. None of the preoperative factors were significant predictors of treatment failure. CONCLUSIONS: Augmentation ileocystoplasty with supratrigonal cystecomy decreased pain and frequency, and increased bladder capacity significantly. There were no severe complications related to surgery during follow up. Augmentation ileocystoplasty with supratrigonal cystectomy is therefore an appropriate final treatment strategy for refractory bladder pain syndrome/interstitial cystitis patients with Hunner's lesion.

Antimicrobial susceptibility pattern and epidemiology of female urinary tract infections in South Korea, 2010-2011.

This study aimed to (i) investigate the antimicrobial susceptibilities of bacteria that cause urinary tract infections (UTIs) in outpatient and inpatient settings and (ii) evaluate the risk factors for emerging antimicrobial drug resistance in UTIs in South Korea. In total, 3,023 samples without duplication were collected from females between 25 and 65 years of age who had been diagnosed with a urinary tract infection. Multicenter patient data were collected using a Web-based electronic system and then evaluated. The isolation rates of Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecium in the outpatient setting were 78.1, 4.7, and 1.3%, respectively; in the inpatient setting, the isolation rates of these microorganisms were 37.8, 9.9, and 14.8%, respectively. The susceptibilities of E. coli to amikacin, amoxicillin-clavulanic acid, cefotaxime, cefoxitin, ciprofloxacin, piperacillin-tazobactam, and imipenem in the outpatient setting were 99.4, 79.8, 89.4, 92.8, 69.8, 96.9, and 100.0%, respectively; in the inpatient setting, the susceptibilities to these antibiotics were 97.8, 73.9, 73.7, 82.1, 53.6, 93.2, and 100.0%, respectively. The most unique and common risk factor for emerging antimicrobial-resistant E. coli, K. pneumoniae, and E. faecium was previous exposure to antimicrobials. On the basis of these data, the use of fluoroquinolones should be reserved until culture data are available for the treatment of UTIs in South Korea. The present study will serve as a useful reference for Far Eastern Asia.

Clinicopathological implications of histological mapping in radical prostatectomy specimens.

OBJECTIVE: The present study aims to elucidate the clinicopathological implications of histological mapping in radical prostatectomy specimens. METHODS: This study included 76 prostatic cancers with histological mapping. The examined characteristics from the histological mappings were the largest tumor dimension, distance from the tumor core to resection margin, tumor dimension from the apex to base, tumor volume, tumor surface area, and proportion of the tumor. In addition, these histological parameters from the histological mapping were compared between patients with positive surgical margin (PSM) and negative surgical margin (NSM). RESULTS: Patients with PSM were significantly correlated with a higher Gleason score and pT stage than those with NSM. Among the histological characteristics from mappings, there were significant correlations between PSM and the largest tumor dimension, tumor volume, tumor surface area, and proportion of tumor (P < 0.001, P < 0.001, P < 0.001, and P = 0.017, respectively). The distance from the tumor core to the resection margin was significantly longer with PSM than with NSM (P = 0.024). According to the linear regression test, the tumor volume, tumor surface area, and largest tumor dimension were significantly correlated with Gleason score and grade (P = 0.019, P = 0.036, and P = 0.016, respectively). There were no significant differences in the histological factors between the apical and non-apical involved subgroups. CONCLUSION: Various clinicopathological characteristics assessed from the histological mappings, such as the tumor volume, tumor surface area, and proportion of the tumor, can be useful for interpreting PSM after radical prostatectomy.

3D organization and function of the cell: Golgi budding and vesicle biogenesis to docking at the porosome complex.

Insights into the three-dimensional (3D) organization and function of intracellular structures at nanometer resolution, holds the key to our understanding of the molecular underpinnings of cellular structure-function. Besides this fundamental understanding of the cell at the molecular level, such insights hold great promise in identifying the disease processes by their altered molecular profiles, and help determine precise therapeutic treatments. To achieve this objective, previous studies have employed electron microscopy (EM) tomography with reasonable success. However, a major hurdle in the use of EM tomography is the tedious procedures involved in fixing, high-pressure freezing, staining, serial sectioning, imaging, and finally compiling the EM images to obtain a 3D profile of sub-cellular structures. In contrast, the resolution limit of EM tomography is several nanometers, as compared to just a single or even sub-nanometer using the atomic force microscope (AFM). Although AFM has been hugely successful in 3D imaging studies at nanometer resolution and in real time involving isolated live cellular and isolated organelles, it has had limited success in similar studies involving 3D imaging at nm resolution of intracellular structure-function in situ. In the current study, using both AFM and EM on aldehyde-fixed and semi-dry mouse pancreatic acinar cells, new insights on a number of intracellular structure-function relationships and interactions were achieved. Golgi complexes, some exhibiting vesicles in the process of budding were observed, and small vesicles were caught in the act of fusing with larger vesicles, possibly representing either secretory vesicle biogenesis or vesicle refilling following discharge, or both. These results demonstrate the power and scope of the combined engagement of EM and AFM imaging of fixed semi-dry cells, capable of providing a wealth of new information on cellular structure-function and interactions.

Roles of NF-κB activation in benign prostatic hyperplasia and association between NF-κB and HIF-1α.

OBJECTIVE: The aim of this study was to elucidate the role of NF-κB activation in benign prostatic hyperplasia (BPH) using immunohistochemistry. METHODS: Immunohistochemical staining for NF-κB was performed and evaluated, dividing into glands and stroma in 101 human BPH tissues. To evaluate the impacts of NF-κB activation on BPH progression, correlations between NF-κB expression and clinical findings, hormone receptors, and HIF-1α were evaluated. RESULTS: NF-κB expression was found in 37.6% and 30.7% in glands and stroma of BPH, respectively. Total and T-zone volumes in transrectal ultrasonography were significantly higher in patients with NF-κB activation than those without NF-κB activation in the stroma. However, NF-κB activation of stroma was not correlated with HIF-1α expression and microvessel density. In subgroup analysis based on NF-κB activation, androgen and progesterone receptors of stroma were highly expressed in HIF-1α negative cases than in HIF-1α positive cases. In cases without NF-κB activation, patients with HIF-1α positivity showed a high frequency of diffuse fibrosis than those with HIF-1α negativity (P = 0.001). CONCLUSION: Taken together, our result showed that NF-κB activation of stroma was significantly correlated with low total and T-zone volumes in transrectal ultrasonography. Diffuse fibrosis was frequently found in patients with NF-κB inactivation and HIF-1α positivity.

The Prevalence of Lower Urinary Tract Symptoms and Overactive Bladder in South Korea: A Cross-Sectional, Population-Based Study.

PURPOSE: Lower urinary tract symptoms (LUTS) affect over half of the adults' population worldwide, with an increasing prevalence among the older age groups. Therefore, with the increasing elderly population, LUTS is an important disease, highlighting the need for accurate data on its prevalence. This present study aimed to investigate the prevalence of LUTS in South Korea. METHODS: The study targeted individuals aged at least 19 years nationwide. We conducted computer-assisted telephone interviews, 80% mobile random digital dialing (RDD) sampling frame, and 20% landline RDD sampling frame between April and May 2020. Questionnaires included The International Prostate Symptom Score (IPSS), the overactive bladder symptom score (OABSS), and the characteristics of respondents. Current International Continence Society definitions were used for individual LUTS and OAB. RESULTS: There were 2,000 respondents, 1,009 (50.4%) were women and 546 (27.3%) were aged ≥60 years. Based on our IPSS questionnaire survey results, 77.9% of the respondents had LUTS; 63.7% had mild symptoms (1-7), 11.7% had moderate symptoms (8-19), and 2.4% had severe symptoms (20-35). The prevalence and severity of LUTS increased with age with 22.1% of respondents aged 60 years and above complaining of moderate or severe LUTS. According to the survey through OABSS, the prevalence of OAB was 9.6%, males were 10.3% and females were 9.0%. CONCLUSION: Based on our survey results, 77.9% of the Korean adult population (over the age of 19) experienced at least one LUTS, and the severity increased with age. The prevalence and severity of OAB increased with age, especially after 40 years; the prevalence of OAB was 9.6%, and 13.4% of them were over 60 years old.

Understanding Brain-Skeletal Muscle Crosstalk Impacting Metabolism and Movement.

Metabolism and movement, among the critical determinants in the survival and success of an organism, are tightly regulated by the brain and skeletal muscle. At the cellular level, mitochondria -that powers life, and myosin - the molecular motor of the cell, have both evolved to serve this purpose. Although independently, the skeletal muscle and brain have been intensively investigated for over a century, their coordinated involvement in metabolism and movement remains poorly understood. Therefore, a fundamental understanding of the coordinated involvement of the brain and skeletal muscle in metabolism and movement holds great promise in providing a window to a wide range of life processes and in the development of tools and approaches in disease detection and therapy. Recent developments in new tools, technologies and approaches, and advances in computing power and machine learning, provides for the first time the opportunity to establish a new field of study, the 'Science and Engineering of Metabolism and Movement'. This new field of study could provide substantial new insights and breakthrough into how metabolism and movement is governed at the systems level in an organism. The design and approach to accomplish this objective is briefly discussed in this article.

A Multicenter, Open-Label, Observational Study Evaluating the Quality of Life After Using a Hydrophilic-Coated Catheter (SpeediCath) With Self-Intermittent Catheterization.

PURPOSE: We evaluated the change in patient quality of life after the use of a hydrophilic-coated catheter (SpeediCath) in adults requiring intermittent catheterization (IC). METHODS: This was a multicenter, open-label, observational study using the Patient Perception of Intermittent Catheterization (PPIC) questionnaire and the Intermittent Self-Catheterization questionnaire (ISC-Q) and safety at 12 and 24 weeks in adult patients who had already used other type of catheters prior to switching to SpeediCath or in patients undergoing self-IC for the first time for any reason. RESULTS: Among a total of 360 subjects, 215 (59.7%) were women, and the mean age was 62.0±13.2 years. At 24 weeks, the satisfaction rate after using SpeediCath was 84.1%, and 80% of patients responded that they could easily perform IC. In total, 81.6% of patients were willing to continue using SpeediCath. The mean ISC-Q score was 54.90±18.65 at 24 weeks. Men found less interference in their daily life by performing IC than women and found it easier to handle the catheter before it was inserted into the urethra. At week 12, the mean change in ISC-Q was significantly greater in patients <65 years (20.24±23.55) than in those ≥65 years (7.57±27.70, P=0.049), but there was no difference at 24 weeks. The most common adverse events were urinary tract infection in 9.72%, gross hematuria in 2.78%, and urethral pain in 1.39%. CONCLUSION: The use of a SpeediCath provided good quality of life for patients who needed self-IC regardless of age or sex.

Involvement of ß-adrenergic receptor in synaptic vesicle swelling and implication in neurotransmitter release.

Secretory vesicle swelling is required for vesicular discharge during cell secretion. The G(αo) -mediated water channel aquaporin-6 (AQP-6) involvement in synaptic vesicle (SV) swelling in neurons has previously been reported. Studies demonstrate that in the presence of guanosine triphosphate (GTP), mastoparan, an amphiphilic tetradecapeptide from wasp venom, activates G(o) protein GTPase, and stimulates SV swelling. Stimulation of G proteins is believed to occur via insertion of mastoparan into the phospholipid membrane to form a highly structured α-helix that resembles the intracellular loops of G protein-coupled adrenergic receptors. Consequently, the presence of adrenoceptors and the presence of an endogenous ß-adrenergic agonist at the SV membrane is suggested. Immunoblot analysis of SV using ß-adrenergic receptor antibody, and vesicle swelling experiments using ß-adrenergic agonists and antagonists, demonstrate the presence of functional ß-adrenergic receptors at the SV membrane. Since a recent study shows vH(+) -ATPase to be upstream of AQP-6 in the pathway leading from G(αo) -mediated swelling of SV, participation of an endogenous ß-adrenergic agonist, in the binding and stimulation of its receptor to initiate the swelling cascade is demonstrated.

Membrane-directed molecular assembly of the neuronal SNARE complex.

Since the discovery and implication of N-ethylmaleimide-sensitive factor (NSF)-attachment protein receptor (SNARE) proteins in membrane fusion almost two decades ago, there have been significant efforts to understand their involvement at the molecular level. In the current study, we report for the first time the molecular interaction between full-length recombinant t-SNAREs and v-SNARE present in opposing liposomes, leading to the assembly of a t-/v-SNARE ring complex. Using high-resolution electron microscopy, the electron density maps and 3D topography of the membrane-directed SNARE ring complex was determined at nanometre resolution. Similar to the t-/v-SNARE ring complex formed when 50 nm v-SNARE liposomes meet a t-SNARE-reconstituted planer membrane, SNARE rings are also formed when 50 nm diameter isolated synaptic vesicles (SVs) meet a t-SNARE-reconstituted planer lipid membrane. Furthermore, the mathematical prediction of the SNARE ring complex size with reasonable accuracy, and the possible mechanism of membrane-directed t-/v-SNARE ring complex assembly, was determined from the study. Therefore in the present study, using both lipososome-reconstituted recombinant t-/v-SNARE proteins, and native v-SNARE present in isolated SV membrane, the membrane-directed molecular assembly of the neuronal SNARE complex was determined for the first time and its size mathematically predicted. These results provide a new molecular understanding of the universal machinery and mechanism of membrane fusion in cells, having fundamental implications in human health and disease.

Characteristics of an Impaired PDT Response.

A concurrent human papilloma virus (HPV) infection potentiates the efficacy of ionizing radiation for treatment of head and neck cancer by promoting apoptosis. Studies in cell culture indicated an opposite effect for photodynamic therapy (PDT) when this leads to mitochondrial and ER photodamage. The explanation for this difference in PDT efficacy remains to be established. While apoptosis was impaired in HPV(-) cells, such cells can be killed via photodamage directed at the ER: this leads to a nonapoptotic death pathway termed paraptosis. No differences in photosensitizer uptake or reactive oxygen species (ROS) production were observed in HPV(+) vs. HPV(-) tumors. We now provide evidence that death pathways initiated by ER/mitochondrial photodamage leading to either paraptosis or apoptosis are impaired in an HPV(+) head and neck cell line. These results illustrate the complex determinants of PDT efficacy, a topic that has yet to be fully explored.

Photodynamic Therapy as a Potent Radiosensitizer in Head and Neck Squamous Cell Carcinoma.

Despite recent advances in therapeutic modalities such as radiochemotherapy, the long-term prognosis for patients with advanced head and neck squamous cell carcinoma (HNSCC), especially nonviral HNSCC, remains very poor, while survival of patients with human papillomavirus (HPV)-associated HNSCC is greatly improved after radiotherapy. The goal of this study is to develop a mechanism-based treatment protocol for high-risk patients with HPV-negative HNSCC. To achieve our goal, we have investigated molecular mechanisms underlying differential radiation sensitivity between HPV-positive and -negative HNSCC cells. Here, we found that autophagy is associated with radioresistance in HPV-negative HNSCC, whereas apoptosis is associated with radiation sensitive HPV-positive HNSCC. Interestingly, we found that photodynamic therapy (PDT) directed at the endoplasmic reticulum (ER)/mitochondria initially induces paraptosis followed by apoptosis. This led to a substantial increase in radiation responsiveness in HPV-negative HNSCC, while the same PDT treatment had a minimal effect on HPV-positive cells. Here, we provide evidence that the autophagic adaptor p62 mediates signal relay for the induction of apoptosis, promoting ionizing radiation (XRT)-induced cell death in HPV-negative HNSCC. This work proposes that ER/mitochondria-targeted PDT can serve as a radiosensitizer in intrinsically radioresistant HNSCC that exhibits an increased autophagic flux.

p62/SQSTM1-induced caspase-8 aggresomes are essential for ionizing radiation-mediated apoptosis.

The autophagy-lysosome pathway and apoptosis constitute vital determinants of cell fate and engage in a complex interplay in both physiological and pathological conditions. Central to this interplay is the archetypal autophagic cargo adaptor p62/SQSTM1/Sequestosome-1 which mediates both cell survival and endoplasmic reticulum stress-induced apoptosis via aggregation of ubiquitinated caspase-8. Here, we investigated the role of p62-mediated apoptosis in head and neck squamous cell carcinoma (HNSCC), which can be divided into two groups based on human papillomavirus (HPV) infection status. We show that increased autophagic flux and defective apoptosis are associated with radioresistance in HPV(-) HNSCC, whereas HPV(+) HNSCC fail to induce autophagic flux and readily undergo apoptotic cell death upon radiation treatments. The degree of radioresistance and tumor progression of HPV(-) HNSCC respectively correlated with autophagic activity and cytosolic levels of p62. Pharmacological activation of the p62-ZZ domain using small molecule ligands sensitized radioresistant HPV(-) HNSCC cells to ionizing radiation by facilitating p62 self-polymerization and sequestration of cargoes leading to apoptosis. The self-polymerizing activity of p62 was identified as the essential mechanism by which ubiquitinated caspase-8 is sequestered into aggresome-like structures, without which irradiation fails to induce apoptosis in HNSCC. Our results suggest that harnessing p62-dependent sequestration of ubiquitinated caspase-8 provides a novel therapeutic avenue in patients with radioresistant tumors.