Lower Breakpoint of Intracranial Amplitude-Pressure Relationship in Normal Pressure Hydrocephalus.

The relationship between intracranial pulse amplitude (AMP) and mean intracranial pressure (ICP) has been previously described. Generally, AMP increases proportionally to rises in ICP. However, at low ICP a lower breakpoint (LB) of amplitude-pressure relationship can be observed, below which pulse amplitude stays constant when ICP varies. Theoretically, below this breakpoint, the pressure-volume relationship is linear (good compensatory reserve, brain compliance stays constant); above the breakpoint, it is exponential (brain compliance decreases with rising ICP).Infusion tests performed in 169 patients diagnosed for idiopathic normal pressure hydrocephalus (iNPH) during the period 2004-2013 were available for analysis. A lower breakpoint was observed in 62 patients diagnosed for iNPH. Improvement after shunt surgery in patients in whom LB was recorded was 77% versus 90% in patients where LB was absent (p < 0.02). There was no correlation between improvement and slope of amplitude-pressure line above LB.The detection of a lower breakpoint is associated with less frequent improvement after shunting in NPH. It may be interpreted that cerebrospinal fluid dynamics of patients working on the flat part of the pressure-volume curve and having a 'luxurious' compensatory reserve, are more frequently caused by brain atrophy, which is obviously not responding to shunting.

Efficacy and Safety of Flow-Diverter Therapy for Recurrent Aneurysms after Stent-Assisted Coiling.

BACKGROUND AND PURPOSE: Flow-diverter treatment for previously stented aneurysms has been reported to be less effective and prone to complications. In this study, we evaluated the effectiveness and safety of flow diverters for recurrent aneurysms after stent-assisted coiling. MATERIALS AND METHODS: Patients who underwent flow-diverter placement for recurrent aneurysms after stent-assisted coiling between March 2015 and March 2019 were recruited. Clinical and radiographic characteristics and clinical and angiographic outcomes were retrospectively evaluated. RESULTS: Among 133 patients who underwent flow-diverter insertion, 17 (male/female ratio = 5:12; mean age, 53.8 years) were treated for recurrent aneurysms after stent placement with (n = 16) or without (n = 1) coiling. Eight patients initially presented with subarachnoid hemorrhage; 7, with headache; and 2, with visual field defects. Angiographic morphology included large/giant saccular in 12 patients, dissecting in 2, fusiform in 1, traumatic pseudoaneurysm in 1, and ruptured blood blister-like aneurysm in 1. The duration between the first treatment and flow-diverter placement ranged from 2 weeks to 15 months (median, 6 months). Flow-diverter placement was successful in all cases without any complications. All patients had favorable outcomes (mRS, 0-2), without any newly appearing symptoms. Aneurysms were followed up with conventional angiography at least once in 6-18 months. Sixteen aneurysms showed complete occlusion, and 1 aneurysm was enlarged. CONCLUSIONS: Results from this case series investigating flow-diverter placement for recurrent aneurysms after stent-assisted coiling suggested that the procedure is safe and effective. Further study in a larger population may be warranted.

Combined effects of diabetes and low household income on mortality: a 12-year follow-up study of 505 677 Korean adults.

AIM: To examine the effects of diabetes, low income and their combination on mortality in the Korean population. METHODS: We analysed a total of 505 677 people (53.9% male) aged 40-79 years old from the National Health Insurance Service-National Health Screening (NHIS-HEALS) cohort. Ten levels of household income were used as indicators of economic status. Diabetes was defined as elevated fasting blood glucose (≥ 6.9 mmol/l) and/or use of glucose-lowering drugs or insulin. Covariates of age, sex, BMI, smoking and Charlson Comorbidity Index were determined at baseline. Outcomes were total and cause-specific mortality over 12 years. Cox's proportional hazard regression models were used to estimate hazard ratios (HRs) for mortality according to the presence of diabetes, household income and their combination. RESULTS: Lower household income was associated with higher mortality from all causes, cardiovascular disease, cancer and non-cancer non-cardiovascular causes. Excessive mortality due to low incomes was observed in both people with and without diabetes. In men, the adjusted HR [95% confidence interval (CI)] of mortality was 1.38 (1.34 to 1.42) for low-income only, 1.48 (1.42 to 1.55) for diabetes only and 1.95 (1.86 to 2.05) for diabetes and low-income combined, relative to the normal glucose and high income group. Corresponding HR (95% CI) in women were 1.19 (1.14 to 1.24), 1.54 (1.44 to 1.64) and 1.87 (1.75 to 2.01), respectively. CONCLUSION: Both low household income and the presence of diabetes independently increase the risk of mortality, but their combined effects on mortality may be different between men and women.

Learning curve for robotic esophagectomy and dissection of bilateral recurrent laryngeal nerve nodes for esophageal cancer.

Dissection of bilateral recurrent laryngeal nerve (RLN) nodes is a technically demanding procedure, but robotic systems have been useful for RLN node dissection. This retrospective study investigated the learning curve for bilateral RLN node dissection in esophageal-cancer patients using a robotic system for esophageal cancer. We retrospectively reviewed 33 consecutive patients who received a robotic esophagectomy and total lymphadenectomy by single surgeon. The patients were divided into either group 1 (initial 20 cases) or group 2 (later 13 cases). The mean patient age was 61.88 ± 9.03 years and 28 (84.8%) patients were male. Most cases were pathologically diagnosed as squamous cell carcinoma. The lesion locations included 3 (9.1%) in the upper esophagus, 12 (63.6%) in the mid esophagus, and 9 (27.3%) in the lower esophagus. Eleven (33.3%) cases were stage I, 7 (21.2%) were stage II, and 15 (45.5%) were stage III. One case in group 2 (3%) suffered operative mortality. Operation time, robot console time, and blood loss were similar between the two groups. The timing of right and left RLN node dissection, the number of total dissected lymph nodes, and the percentage of dissected right and left RLN nodes were also comparable. However, the incidence of vocal cord palsy was significantly lower in group 2 (55% vs. 0%, p= 0.02). The incidence of other operative complications did not vary between the two groups. Even though operative outcomes and incidence of other complications were comparable between the two groups, the incidence of vocal cord palsy decreased significantly after 20 cases. Thus, we conclude that a minimum of 20 cases is required before a surgeon is experienced enough to perform safe dissection of bilateral RLN nodes.

Co-clinical trials demonstrate predictive biomarkers for dovitinib, an FGFR inhibitor, in lung squamous cell carcinoma.

BACKGROUND: We conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC). METHODS: The PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected to in vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling. RESULTS: The PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations of FGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18 key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib. CONCLUSIONS: FGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Natural history and factors associated with ulnar-sided wrist pain in distal radial fractures treated by plate fixation.

UNLABELLED: We documented longitudinal changes in the incidence of ulnar-sided wrist pain after distal radial fractures treated by plate fixation and identified factors associated with ulnar-sided wrist pain. A total of 140 patients were enrolled in this study. Radiographs were taken 3 months after operation, and were used to measure radial inclination, anterior angulation and ulnar variance, and to identify the presence of an ulnar styloid fracture. Clinical assessments at the same time included grip strengths, ranges of wrist motion and the patient-rated wrist evaluation questionnaire. The presence of ulnar-sided wrist pain was noted at each follow-up visit. The incidence of ulnar-sided wrist pain decreased significantly with time after surgery (22 patients at 3 months, 11 patients at 6 months and three patients at 12 months). The mean age, sex, the presence of an ulnar styloid fracture and the classification of the distal radial fracture were not factors that were associated with a higher incidence of ulnar-sided wrist pain, but there was an association between higher patient-rated wrist evaluation scores and the presence of ulnar-sided wrist pain. LEVEL OF EVIDENCE: Prognosis, Level IV.

Robot-assisted thoracoscopic esophagectomy with extensive mediastinal lymphadenectomy: experience with 114 consecutive patients with intrathoracic esophageal cancer.

The study aims to report the operative outcomes of robot-assisted thoracoscopic esophagectomy (RATE) with extensive mediastinal lymphadenectomy (ML) for intrathoracic esophageal cancer. We analyzed a prospective database of 114 consecutive patients who underwent RATE with lymph node dissection along recurrent laryngeal nerve (RLN) followed by cervical esophagogastrostomy. The study included 104 men with a mean age of 63.1 ± 0.8 years. Of these, 110 (96.5%) had squamous cell carcinoma, and the location of the tumor was upper esophagus in 7 (6.1%), middle in 62 (54.4%), and lower in 45 (39.5%). Preoperative concurrent chemoradiation was performed in 15 patients (13.2%). All but one patient underwent successful RATE, and R0 resection was achieved in 111 patients (97.4%). Extended ML and total ML were performed in 24 (21.1%) and 90 (78.9%) patients, respectively. Total operation time was 419.6 ± 7.9 minutes, and robot console time was 206.6 ± 5.2 minutes. The mean number of total, mediastinal, and RLN nodes was 43.5 ± 1.4, 24.5 ± 1.0, and 9.7 ± 0.7, respectively. The most common complication was RLN palsy (30, 26.3%), followed by anastomotic leakage (17, 14.9%) and pulmonary complications (11, 9.6%). Median hospital stay was 16 days, and 90-day mortality was observed in three patients (2.5%). On multivariate analysis, preoperative concurrent chemoradiation was a risk factor for pulmonary complications (odds ratio 7.42, 95% confidence interval 1.91-28.8, P = 0.004). RATE with extensive ML could be performed safely with acceptable postoperative outcomes. Long-term survival data should be followed in the future to verify the oncological outcome of the procedure.

A prospective, randomized, placebo-controlled trial of on-Demand vs. nightly sildenafil citrate as assessed by Rigiscan and the international index of erectile function.

Multiple studies have evaluated the use of PDE5 inhibitors in penile rehabilitation following nerve-sparing prostatectomy. These studies have evaluated the use of various pharmacologic agents as well as various approaches to treatment (on-demand vs. rehabilitative). Most of these studies relied on self-reported outcomes to determine efficacy of the therapy which could allow response bias to affect their results. The aim of this study was to evaluate the effects of nightly sildenafil citrate therapy during penile rehabilitation, using nocturnal penile rigidity (RigiScan(™), Gotop Medical, Inc., St. Paul, MN, USA) in addition to the IIEF-EF. Patients with localized prostate cancer and normal erectile function prior to nsRP were randomized to take either nightly 50 mg sildenafil citrate or placebo starting the night following surgery. Both groups were allowed on-demand sildenafil citrate. Erectile function was evaluated at 2 weeks, 3, 6, 9 and 12 months post-operatively, with a final assessment made at 13 months, following a 1 month drug washout. At all time points, self-reported (IIEF-EF) and objective (RigiScan(™)) measures were obtained and evaluated. About 74 of 97 randomized patients completed the study. On completion, 40% of patients in each group had normal erectile function based on RigiScan(™) (p = 1.0). Additionally, no statistical differences were seen using the IIEF-EF domain (32.4% of placebo, 29% of treatment; p = 0.79). Multivariable analysis showed no significant differences in erectile function based on treatment intervention. Results did show that African-American men in this cohort were at higher risk for lower RigiScan(™) scores over time (OR: 0.48, p = 0.0399). This study demonstrates that nightly sildenafil citrate does not provide a therapeutic benefit for recovery of erectile function post-prostatectomy when compared to on-demand dosing using both self-reported as well as objective measures. Differences in objective recovery parameters based on patients' race/ethnicity warrant further investigation.

Fyn is a redox sensor involved in solar ultraviolet light-induced signal transduction in skin carcinogenesis.

Solar ultraviolet (UV) light is a major etiological factor in skin carcinogenesis, with solar UV-stimulated signal transduction inducing pathological changes and skin damage. The primary sensor of solar UV-induced cellular signaling has not been identified. We use an experimental system of solar simulated light (SSL) to mimic solar UV and we demonstrate that Fyn is a primary redox sensor involved in SSL-induced signal transduction. Reactive oxygen species (ROS) generated by SSL exposure directly oxidize Cys488 of Fyn, resulting in increased Fyn kinase activity. Fyn oxidation was increased in mouse skin after SSL exposure and Fyn-knockout mice formed larger and more tumors compared with Fyn wild-type mice when exposed to SSL for an extended period of time. Murine embryonic fibroblasts (MEFs) lacking Fyn and cells in which Fyn expression was knocked down were resistant to SSL-induced apoptosis. Furthermore, cells expressing mutant Fyn (C448A) were resistant to SSL-induced apoptosis. These findings suggest that Fyn acts as a regulatory nexus between solar UV, ROS and signal transduction during skin carcinogenesis.

Performance of HbA1c for the prediction of diabetes in a rural community in Korea.

AIM: To investigate the performance of HbA1c in predicting incident diabetes among Korean adults with normal fasting glucose and impaired fasting glucose levels. METHODS: This study used data from the Korean Genome Epidemiology Study-Kangwha Study. A prospective analysis was carried out on 2079 people (820 men and 1259 women) who completed follow-up examinations up until 2013. Diabetes was defined as fasting blood glucose level ≥ 7.0 mmol/l, HbA1c level ≥ 48 mmol/mol (6.5%), or current treatment for diabetes. Areas under the receiver-operating characteristic curves were used to assess the different performances of HbA1c , glucose and insulin in predicting diabetes. RESULTS: The median follow-up time was 3.97 years, during which 7.7% of men and 6.3% of women developed incident diabetes. The areas under the receiver-operating curves (95% CI) for diabetes prediction were 0.740 (0.692-0.787) for HbA1c , 0.716 (0.667-0.764) for glucose and 0.598 (0.549-0.648) for insulin. HbA1c showed better predictive power in people with impaired fasting glucose (area under the curve 0.753, 95% CI 0.685-0.821) than in those with normal glucose (area under the curve 0.648, 95% CI 0.577-0.719). An HbA1c threshold of 40 mmol/mol (5.8%) was found to have the highest predictive value for diabetes, with a relative risk of 6.30 (95% CI 3.49-11.35) in men and 3.52 (95% CI 2.06-6.03) in women after adjusting for age, waist circumference, triglycerides, hypertension, family history of diabetes, smoking, alcohol intake, exercise and baseline glucose level. CONCLUSIONS: HbA1c can be used to identify people at high risk for the development of diabetes, especially in those with impaired fasting glucose levels.

Genome-wide microRNA expression profiling in placentas of fetuses with Down syndrome.

INTRODUCTION: Down syndrome (DS) is the most common aneuploidy, caused by an extra copy of all or part of chromosome 21 (chr21). Differential microRNA (miRNA) expression is involved in many human diseases including DS. However, the genome-wide changes in miRNA expression in DS fetal placentas have yet to be determined, and the function of these changes is also unclear. METHODS: We profiled genome-wide miRNA expression in placenta samples from euploid or DS fetuses by using microarray technology and predicted the functions of differentially expressed miRNAs using bioinformatics tools. RESULTS: Thirty-four miRNAs were significantly differentially expressed in the DS placenta compared with the normal placenta (16 up-regulated and 18 down-regulated). However, expression of chr21-derived miRNAs did not change. Predicted target genes included 7434 genes targeted by up-regulated miRNAs and 6071 genes targeted by down-regulated miRNAs. Seventy-six of these target genes were located on chr21 (10 genes controlled by down-regulated miRNAs and 34 genes by up-regulated miRNAs, and 32 genes by both). Target genes on chr21 were significantly associated with DS and DS-related disorders, such as mental retardation, neurobehavioral manifestations, and congenital abnormalities. DISCUSSION: To our knowledge, this is the first genome-wide study to comprehensively survey placental miRNAs in DS fetuses. Our results provide new insight into miRNA expression in placentas of fetuses with DS. Additionally, our findings indicate that the differentially expressed miRNAs in the DS placenta may potentially affect various pathways related to DS pathogenesis.

In vitro assessment of the gastrointestinal tolerance and immunomodulatory function of Bacillus methylotrophicus isolated from a traditional Korean fermented soybean food.

AIMS: This study aimed to investigate the potential of Bacillus methylotrophicus as a probiotic. METHODS AND RESULTS: A Bacillus isolate designated strain C14 was isolated from Korean traditional fermented soybean paste (doenjang). The strain was identified, and its physiological and biochemical properties were characterized. The gastrointestinal tolerance and immunomodulatory function of strain C14 were also investigated. Strain C14 was identified as B. methylotrophicus by analysis of its biochemical properties using the API 50CHB system and by phylogenetic analysis of the 16S rDNA sequence. Strain C14 showed >80% and >75% of survival for artificial gastric juices (pH 2.5 and 1% pepsin) and 0.5% (w/v) bile salt, respectively. Heat-killed B. methylotrophicus C14 inhibited the adhesion of various pathogens and enhanced the adhesion of probiotic bacteria to Caco-2 cells. The heat-killed cells also induced high levels of immune cell proliferation compared with the control and stimulated interleukin-6 and tumour necrosis factor-α production in mouse macrophages. CONCLUSIONS: Bacillus methylotrophicus C14 could be used as a probiotic. SIGNIFICANCE AND IMPACT OF THE STUDY: Recently identified B. methylotrophicus is a new potential probiotic with high gastrointestinal tolerance.

The risk factors associated with subluxation of the distal interphalangeal joint in mallet fracture.

Surgical fixation is recommended when a mallet fracture involves more than one-third of the articular surface of the distal phalanx. This recommendation originates from the idea that involvement of more than one-third of the base of the distal phalanx causes subluxation of the distal interphalangeal (DIP) joint. Eighty-six fingers of 85 patients with a mallet fracture involving more than one-third of the articular surface of the distal phalanx were enrolled in this study. Patients were allocated on the basis of subluxation of the DIP joint into a group with no subluxation or a group with subluxation. These two groups were compared with respect to age, sex, fracture size, fracture displacement, time to finger immobilizer application, and initial extensor lag of the DIP joint. Backward stepwise multiple logistic regression analysis was performed to identify the risk factors of DIP joint subluxation, and receiver operating curve analysis was used to calculate the optimal cut-off point for the risk factors. Half of our patients with a mallet fracture involving > one-third of the articular surface of the distal phalanx showed subluxation of the DIP joint. A significant intergroup difference was found for fracture size and time to application of a finger immobilizer, but no significant difference was observed for other parameters. The risk factors of DIP joint subluxation were fracture size and time to application of finger immobilizer. The optimal cut-off values for the development of DIP joint subluxation were 48% for the fracture size and 12.5 days for time to finger immobilizer application.

Recurrence of hepatocellular carcinoma: importance of mRECIST response to chemoembolization and tumor size.

Determining risk for recurrence of hepatocellular carcinoma (HCC) following liver transplantation (LT) is an important clinical need. We assessed consecutive patients who underwent LT for HCC following sequential transarterial chemoembolization (TACE). Treatment response was assessed using modified response evaluation criteria in solid tumors (mRECIST) categories: complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). Cox proportional hazard models were used to predict HCC recurrence. One hundred seventy-three patients underwent TACE and imaging to assess response prior to LT. TACE responses were: CR = 23.7%, PR = 24.3%, SD = 27.7% and PD = 24.3%. Five-year HCC recurrence rate was 5.3% in patients responding to TACE (CR/PR), versus 17.6%, among patients who did not respond (SD/PD, p = 0.014). In multivariate analysis, independent pre-LT predictors of recurrence were response to TACE and largest radiologic size of tumor (>3 cm vs. ≤3 cm). HCC recurrence rate for patients with tumor size >3 cm and no response to TACE was 35.8%, compared with 1.9% for patients with tumor size ≤3 cm and response to TACE (p = 0.0007). We conclude that mRECIST criteria and tumor size differentiate patients with high or low likelihood of HCC recurrence after LT. These findings raise the possibility of incorporating response to TACE and largest tumor size to identify patients at highest risk for HCC recurrence.

Extracellular visfatin activates gluconeogenesis in HepG2 cells through the classical PKA/CREB-dependent pathway.

Adipokines reportedly affect hepatic gluconeogenesis, and the adipokine visfatin is known to be related to insulin resistance and type 2 diabetes. However, whether visfatin contributes to hepatic gluconeogenesis remains unclear. Visfatin, also known as nicotinamide phosphoribosyltransferase (NAMPT), modulates sirtuin1 (SIRT1) through the regulation of nicotinamide adenine dinucleotide (NAD). Therefore, we investigated the effect of extracellular visfatin on glucose production in HepG2 cells, and evaluated whether extracellular visfatin affects hepatic gluconeogenesis via an NAD+-SIRT1-dependent pathway. Treatment with visfatin significantly increased glucose production and the mRNA expression and protein levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in HepG2 cells in a time- and concentration-dependent manner. Knockdown of SIRT1 had no remarkable effect on the induction of gluconeogenesis by visfatin. Subsequently, we evaluated if extracellular visfatin stimulates the production of gluconeogenic enzymes through the classical protein kinase A (PKA)/cyclic AMP-responsive element (CRE)-binding protein (CREB)-dependent process. The phosphorylation of CREB and PKA increased significantly in HepG2 cells treated with visfatin. Additionally, knockdown of CREB and PKA inhibited visfatin-induced gluconeogenesis in HepG2 cells. In summary, extracellular visfatin modulates glucose production in HepG2 cells through the PKA/CREB pathway, rather than via SIRT1 signaling.

RIP2/RICK-dependent cytokine production upon Yersinia enterocolitica infection in macrophages with TLR4 deficiency.

Receptor-interacting protein 2 (RIP2) is a caspase recruitment domain (CARD)-containing serine/threonine kinase that is activated by NOD1 or NOD2 recognition of their ligands and essential for the activation of NF-κB and mitogen-activated protein kinase (MAPK). RIP2 has been known to play an important role in innate immune responses against certain bacterial infection. However, the role and interplay of RIP2 with TLR signalling on cytokine production in macrophages against Yersinia enterocolitica infection remains poorly understood. In the present study, we examined whether RIP2 is essential for Yersinia-induced production of cytokines in macrophages. Our results showed that naïve RIP2-deficient macrophages produced similar level of IL-6, TNF-α and IL-10 upon Y. enterocolitica infection compared with wild-type macrophages. However, the production of IL-6, TNF-α and IL-10 by Y. enterocolitica was impaired in RIP2-deficient macrophages after lipopolysaccharide (LPS) pretreatment, a TLR4-tolerant condition. In addition, RIP2 inhibitors, SB203580, PP2, and gefitinib, reduced IL-6 production in TLR4-deficient macrophages in response to Y. enterocolitica, whereas they did not affect the cytokines production in WT cells. These results demonstrate that RIP2 may play an important role in proinflammatory cytokine production in macrophages at the absence of TLR signalling.

SVCT-2 in breast cancer acts as an indicator for L-ascorbate treatment.

L-ascorbate (L-ascorbic acid, vitamin C) clearly has an inhibitory effect on cancer cells. However, the mechanism underlying differential sensitivity of cancer cells from same tissue to L-ascorbate is yet to be clarified. Here, we demonstrate that L-ascorbate has a selective killing effect, which is influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human breast cancer cells. Treatment of human breast cancer cells with L-ascorbate differentially induced cell death, dependent on the SVCT-2 protein level. Moreover, knockdown of endogenous SVCT-2 via RNA interference in breast cancer cells expressing high levels of the protein induced resistance to L-ascorbate treatment, whereas transfection with SVCT-2 expression plasmids led to enhanced L-ascorbate chemosensitivity. Surprisingly, tumor regression by L-ascorbate administration in mice bearing tumor cell xenograft also corresponded to the SVCT-2 protein level. Interestingly, SVCT-2 expression was absent or weak in normal tissues, but strongly detected in tumor samples obtained from breast cancer patients. In addition, enhanced chemosensitivity to L-ascorbate occurred as a result of caspase-independent autophagy, which was mediated by beclin-1 and LC3 II. In addition, treatment with N-acetyl-L-cysteine, a reactive oxygen species (ROS) scavenger, suppressed the induction of beclin-1 and LC3 II, implying that the differential SVCT-2 protein-dependent L-ascorbate uptake was attributable to intracellular ROS induced by L-ascorbate, subsequently leading to autophagy. These results suggest that functional SVCT-2 sensitizes breast cancer cells to autophagic damage by increasing the L-ascorbate concentration and intracellular ROS production and furthermore, SVCT-2 in breast cancer may act as an indicator for commencing L-ascorbate treatment.

p21-Activated kinase 4 promotes prostate cancer progression through CREB.

Prostate cancer is initially androgen-dependent but, over time, usually develops hormone- and chemo-resistance. The present study investigated a role for p21-activated kinase 4 (PAK4) in prostate cancer progression. PAK4 activation was markedly inhibited by H89, a specific protein kinase A (PKA) inhibitor, and PAK4 was activated by the elevation of cAMP. The catalytic subunit of PKA interacted with the regulatory domain of PAK4, and directly phosphorylated PAK4 at serine 474 (S474). Catalytically active PAK4 enhanced the transcriptional activity of CREB independent of S133 phosphorylation. Stable knockdown of PAK4 in PC-3 and DU145 prostate cancer cells inhibited tumor formation in nude mice. Decreased tumorigenicity correlated with decreased expression of CREB and its targets, including Bcl-2 and cyclin A1. Additionally, in androgen-dependent LNCap-FGC cells, PAK4 regulated cAMP-induced neuroendocrine differentiation, which is known to promote tumor progression. Finally, PAK4 enhanced survival and decreased apoptosis following chemotherapy. These results suggested that PAK4 regulates progression toward hormone- and chemo-resistance in prostate cancer, and this study identified both a novel activation mechanism and potential downstream effector pathways. Therefore, PAK4 may be a promising therapeutic target in prostate cancer.