Tetrahedral amorphous carbon prepared filter cathodic vacuum arc for hole transport layers in perovskite solar cells and quantum dots LEDs.

(ta-C) films coated through the filtered cathodic vacuum arc (FCVA) process as a hole transport layer (HTL) for perovskite solar cells (PSCs) and quantum dot light-emitting diodes (QDLEDs). The p-type ta-C film has several remarkable features, including ease of fabrication without the need for thermal annealing, reasonable electrical conductivity, optical transmittance, and a high work function. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy examinations show that the electrical properties (sp3/sp2 hybridized bond) and work function of the ta-C HTL are appropriate for PSCs and QDLEDs. In addition, in order to correlate the performance of the devices, the optical, surface morphological, and structural properties of the FCVA-grown ta-C films with different thicknesses (5 ~ 20 nm) deposited on the ITO anode are investigated in detail. The optimized ta-C film with a thickness of 5 nm deposited on the ITO anode had a sheet resistance of 10.33 Ω-2, a resistivity of 1.34 × 10-4 Ω cm, and an optical transmittance of 88.97%. Compared to the reference PSC with p-NiO HTL, the PSC with 5 nm thick ta-C HTL yielded a higher power conversion efficiency (PCE, 10.53%) due to its improved fill factor. Further, the performance of QDLEDs with 5 nm thick ta-C hole injection layers (HIL) showed better than the performance of QDLEDs with different ta-C thicknesses. It is concluded that ta-C films have the potential to serve as HTL and HIL in next-generation PSCs and QDLEDs.

Intermediate PSA half-life after neoadjuvant hormone therapy predicts reduced risk of castration-resistant prostate cancer development after radical prostatectomy.

BACKGROUND: The magnitude and rapidity of the tumor response to androgen deprivation is known to predict the durability of the therapy. We have investigated the predictive value of categorizing patients by the half-life of PSA under neoadjuvant androgen deprivation therapy in patients with biochemical recurrence after radical prostatectomy. METHODS: Medical records of 317 patients who received neoadjuvant androgen deprivation therapy before radical prostatectomy and developed biochemical recurrence were analyzed. The patients were categorized into five groups according to PSA half-life. Risk of developing castration resistance was evaluated by Kaplan-Meier analysis and by Cox proportional risk regression analysis. RESULTS: The median follow-up duration was 50.1 months (IQR 31.8-68.7) and median PSA half-life was 22.1 days (IQR 12.7-38.4). Comparison of survival curves revealed that patients in the intermediate response group showed significantly lower 5-year castration-resistant prostate cancer rate (37.5%) compared to non-response and ultra-rapid response groups (63.6%, p = 0.007; 56.1%, p = 0.031; respectively). In the multivariate regression model, intermediate response compared to non-response was associated with significantly reduced risk of castration resistance development (hazard ratio 0.397, 95% confidence interval 0.191-0.823, p = 0.013) and overall mortality (hazard ratio 0.138, 95% confidence interval 0.033-0.584, p = 0.007). When subcategorized by Gleason score, Kaplan-Meier curve revealed that, in the high Gleason score stratum, 5-year castration-resistant prostate cancer rate for intermediate response group (44.0%) was exceptionally lower than that in non-response group (66.7%, p = 0.047), while castration resistance increased in other groups. CONCLUSION: Short PSA half-life as well as no response after androgen deprivation is associated with increased risk of treatment failure compared to intermediate PSA half-life.

Impact of lymphovascular invasion on lymph node metastasis for patients undergoing radical prostatectomy with negative resection margin.

BACKGROUND: The association between lymphovascular invasion and lymphatic or hematogenous metastasis has been suspected, with conflicting evidence. We have investigated the association between the risk of biochemical recurrence and lymphovascular invasion in resection margin negative patients, as well as its association with lymph node metastasis. METHODS: One thousand six hundred thirty four patients who underwent radical prostatectomy from 2005 to 2014 were selected. Patients with bone or distant organ metastasis at the time of operation were excluded. Survival analysis was performed to assess biochemical recurrence, metastasis and mortality risks by Kaplan-Meier analysis and multivariate Cox proportional hazard regression. Odds of lymph node metastasis were evaluated by Logistic regression. RESULTS: LVI was detected in 118 (7.4%) patients. The median follow-up duration was 33.1 months. In the Kaplan-Meier analysis, lymphovascular invasion was associated with significantly increased 5-year and 10-year BCR rate (60.2% vs. 39.1%, 60.2% vs. 40.1%, respectively; p < 0.001), 10-year bone metastasis rate and cancer specific mortality (16.9% vs. 5.1%, p = 0.001; 6.8% vs. 2.7%, p = 0.034, respectively) compared to patients without LVI. When stratified by T stage and resection margin status, lymphovascular invasion resulted in significantly increased 10-year biochemical recurrence rate in T3 patients both with and without positive surgical margin (p = 0.008, 0.005, respectively). In the multivariate Cox regression model lymphovascular invasion resulted in 1.4-fold BCR risk and 1.7-fold metastasis risk increase (95% CI 1.045-1.749, 1.024-2.950; p = 0.022, 0.040, respectively). Lymphovascular invasion was revealed to be strongly associated with lymph node metastasis in the multivariate Logistic regression (OR 4.317, 95% CI 2.092-8.910, p < 0.001). CONCLUSION: Lymphovascular invasion increases the risk of recurrence in T3 patients regardless of margin status, by accelerating lymph node metastasis and distant organ metastasis.

The prognostic significance of postoperative neutrophil-to-lymphocyte ratio after radical prostatectomy for localized prostate cancer.

BACKGROUND: The pretreatment neutrophil-to-lymphocyte ratio has prognostic value after radical prostatectomy for treating localized prostate cancer. However, the use of postoperative neutrophil-to-lymphocyte ratio has not been evaluated in this population. We investigated the prognostic significance of early postoperative neutrophil-to-lymphocyte ratio after radical prostatectomy for prostate cancer. METHODS: We retrospectively reviewed clinical data from 2,302 patients with localized prostate cancer who underwent radical prostatectomy at our institution between years 2000 and 2010. Only patients with pre- and postoperative complete blood counts with differential results were included. Patients who received neoadjuvant or postoperative adjuvant treatment and those without adequate medical records were excluded. Kaplan-Meier analyses were performed to analyze biochemical recurrence-free survival and overall survival rates. Univariate and multivariate Cox regression models were used for each endpoint. RESULTS: Kaplan-Meier curves showed that high postoperative neutrophil-to-lymphocyte ratio (>3.5) was significantly associated with decreased biochemical recurrence-free survival (p = 0.009) and overall survival (p = 0.010). In the univariate and multivariate Cox regression analyses, high postoperative neutrophil-to-lymphocyte ratio was a significant predictor of biochemical recurrence (hazard ratio 1.270, p = 0.008) and overall survival (hazard ratio 1.437, p = 0.033). CONCLUSIONS: Our results demonstrate that postoperative neutrophil-to-lymphocyte ratio is an independent factor for biochemical recurrence and overall survival in patients who underwent radical prostatectomy for prostate cancer. These findings suggest that neutrophil-to-lymphocyte ratio can be a potentially valuable tool for stratifying high-risk patients and facilitating choices of postoperative therapy in patients with prostate cancer.

Prognostic Significance of the Proportion of Ductal Component in Ductal Adenocarcinoma of the Prostate.

PURPOSE: In prostate cancer ductal adenocarcinoma is mixed with the usual acinar adenocarcinoma. However, to our knowledge whether the proportion of the ductal component affects oncologic outcomes is currently unknown. We investigated whether the proportion of the ductal component predicts oncologic outcomes in ductal adenocarcinoma. MATERIALS AND METHODS: We retrospectively reviewed clinical data on 3,038 patients with prostate cancer who underwent radical prostatectomy at our institution between 2005 and 2014. We excluded patients who received neoadjuvant or adjuvant treatment. Patients were stratified based on the proportion of the ductal component. We compared the probability of biochemical recurrence between groups and investigated how the proportion of the ductal component influences biochemical recurrence using Kaplan-Meier estimates and Cox regression models, respectively. RESULTS: Of 2,648 patients 101 (3.8%) had ductal adenocarcinoma and 2,547 (96.2%) had acinar adenocarcinoma. Freedom from biochemical recurrence in patients with ductal adenocarcinoma was significantly lower than in those with acinar adenocarcinoma (p <0.001). When ductal cases were stratified by the proportion of the ductal component, freedom from biochemical recurrence in the high ductal component group was significantly lower compared to that in the low ductal component group (30% or greater vs less than 30%, p = 0.023). On univariate and multivariate Cox regression analyses, a high ductal component was a significant predictor of biochemical recurrence (p <0.001). CONCLUSIONS: The prognosis for ductal adenocarcinoma can be stratified by the proportion of the ductal component. This marker could potentially be used as a surrogate for poor prognosis or as a determinant for adjuvant therapy.

Prognostic Significance of Vas Deferens Invasion After Radical Prostatectomy in Patients with Pathological Stage T3b Prostate Cancer.

BACKGROUND: Seminal vesicle invasion (SVI) is associated with adverse clinical outcomes in prostate cancer (PCa) patients. Despite its anatomical similarity and close proximity to the seminal vesicle, the prognostic significance of vas deferens invasion (VDI) by PCa has not been elucidated. For these reasons, we investigated the impact of VDI on the oncological outcome of pT3b PCa in association with SVI. METHODS: We retrospectively reviewed the medical records of 3359 patients who had undergone a radical prostatectomy at our institution between January 2000 and December 2014 for PCa. Patients who received neoadjuvant or adjuvant treatment (radiation, androgen deprivation therapy, or both) and those without adequate medical records were excluded. A Kaplan-Meier analysis was performed to analyze biochemical recurrence-free survival (BCRFS), and a Cox regression model was used to test the influence of VDI on biochemical recurrence (BCR). RESULTS: Of 350 patients with pathologically confirmed SVI (pT3b), 87 (24.9%) had VDI, while the remaining 263 patients (75.1%) had isolated SVI. Compared with SVI patients without VDI, SVI patients with VDI were noted to have a significantly worse 5-year BCRFS (25.1 vs. 17.1%, respectively). VDI was a significant predictor of BCR in multivariate Cox regression analysis (hazard ratio 1.39, 95% confidence interval 1.02-1.90; p = 0.039). CONCLUSIONS: Our results shows that the prognosis of PCa with SVI might be further stratified by VDI status, thus suggesting the role of VDI either as a surrogate for poor prognosis or as a determinant for adjuvant therapy.

Association of Anterior and Lateral Extraprostatic Extensions with Base-Positive Resection Margins in Prostate Cancer.

INTRODUCTION: Positive surgical margins (PSM) detected in the radical prostatectomy specimen increase the risk of biochemical recurrence (BCR). Still, with formidable number of patients never experiencing BCR in their life, the reason for this inconsistency has been attributed to the artifacts and to the spontaneous regression of micrometastatic site. To investigate the origin of margin positive cancers, we have looked into the influence of extraprostatic extension location on the resection margin positive site and its implications on BCR risk. MATERIALS & METHODS: The clinical information and follow-up data of 612 patients who had extraprostatic extension and positive surgical margin at the time of robot assisted radical prostatectomy (RARP) in the single center between 2005 and 2014 were modeled using Fine and Gray's competing risk regression analysis for BCR. Extraprostatic extensions were divided into categories according to location as apex, base, anterior, posterior, lateral, and posterolateral. Extraprostatic extensions were defined as presence of tumor beyond the borders of the gland in the posterior and posterolateral regions. Tumor admixed with periprostatic fat was additionally considered as having extraprostatic extension if capsule was vague in the anterior, apex, and base regions. Positive surgical margins were defined as the presence of tumor cells at the inked margin on the inspection under microscopy. Association of these classifications with the site of PSM was evaluated by Cohen's Kappa analysis for concordance and logistic regression for the odds of apical and base PSMs. RESULTS: Median follow-up duration was 36.5 months (interquartile range[IQR] 20.1-36.5). Apex involvement was found in 158 (25.8%) patients and base in 110 (18.0%) patients. PSMs generally were found to be associated with increased risk of BCR regardless of location, with BCR risk highest for base PSM (HR 1.94, 95% CI 1.40-2.68, p<0.001) after adjusting for age, initial prostate-specific antigen, pathologic Gleason score, and pathologic T stage in the multivariate model. Logistic regression for PSM site revealed no significant correlation of apex PSM with extraprostatic extension location, while base PSM was associated with increased odds of anterior (OR 2.513, 95% CI 1.425-4.430, p = 0.001) and lateral (OR 2.715, 95% CI 1.735-4.250, p<0.001) extraprostatic extension. CONCLUSION: Extension into the extraprostatic tissue on some specific locations do not share the same recur risk due to the different anatomical structures surrounding the organ. Anterior and lateral EPEs are prone to leave PSM on the base of the prostate, probably because of the lack of anatomical barricades slowing down the direct invasion process. More study on the pattern of spread of the tumors found to have extraprostatic extension is suggested for optimal planning of the operation extent and of the adjuvant radiotherapy.

Optimal Skin-to-Stone Distance Is a Positive Predictor for Successful Outcomes in Upper Ureter Calculi following Extracorporeal Shock Wave Lithotripsy: A Bayesian Model Averaging Approach.

OBJECTIVES: To investigate whether skin-to-stone distance (SSD), which remains controversial in patients with ureter stones, can be a predicting factor for one session success following extracorporeal shock wave lithotripsy (ESWL) in patients with upper ureter stones. PATIENTS AND METHODS: We retrospectively reviewed the medical records of 1,519 patients who underwent their first ESWL between January 2005 and December 2013. Among these patients, 492 had upper ureter stones that measured 4-20 mm and were eligible for our analyses. Maximal stone length, mean stone density (HU), and SSD were determined on pretreatment non-contrast computed tomography (NCCT). For subgroup analyses, patients were divided into four groups. Group 1 consisted of patients with SSD<25th percentile, group 2 consisted of patients with SSD in the 25th to 50th percentile, group 3 patients had SSD in the 50th to 75th percentile, and group 4 patients had SSD≥75th percentile. RESULTS: In analyses of group 2 patients versus others, there were no statistical differences in mean age, stone length and density. However, the one session success rate in group 2 was higher than other groups (77.9% vs. 67.0%; P = 0.032). The multivariate logistic regression model revealed that shorter stone length, lower stone density, and the group 2 SSD were positive predictors for successful outcomes in ESWL. Using the Bayesian model-averaging approach, longer stone length, lower stone density, and group 2 SSD can be also positive predictors for successful outcomes following ESWL. CONCLUSIONS: Our data indicate that a group 2 SSD of approximately 10 cm is a positive predictor for success following ESWL.

A case report of testicular sparganosis misdiagnosed as testicular tumor.

Sparganosis is a parasitic infestation of human by plerocercoid larvae. Sparganum is usually reported to be found in the subcutaneous tissues as well as other organs, including scrotum. However, testicular sparganosis is extremely rare, because of strong capsule of tunica albuginea. An urban-living 54-yr-old Korean man presented with left scrotal pain for 6 yr. Both testes look normal physically. Ultrasonography revealed poorly defined, heterogeneous mass with increased echogenicity in the left testis. This case was misdiagnosed as testicular tumor and underwent orchiectomy, but was diagnosed as testicular sparganosis by histopathology. Sparganosis should be included for differential diagnosis of testis tumor in countries where sparganosis is prevalent.

Intracavernous delivery of freshly isolated stromal vascular fraction rescues erectile function by enhancing endothelial regeneration in the streptozotocin-induced diabetic mouse.

INTRODUCTION: Men with diabetic erectile dysfunction (ED) often have severe endothelial dysfunction and respond poorly to oral phosphodiesterase-5 inhibitors. AIM: To examine whether and how freshly isolated stromal vascular fraction (SVF) promotes cavernous endothelial regeneration and restores erectile function in diabetic animals. METHODS: Eight-week-old C57BL/6J mice were used. Diabetes was induced by intraperitoneal injection of streptozotocin. SVF was isolated from epididymal adipose tissues of green fluorescence protein transgenic mice. At 8 weeks after the induction of diabetes, the animals were divided into six groups: controls, diabetic mice, and diabetic mice treated with a single intracavernous injection of phosphate-buffered saline (PBS) or SVF (1 × 10(4) cells, 1 × 10(5) cells, or 2 × 10(5) cells/20 µL, respectively). MAIN OUTCOME MEASURES: Two weeks later, erectile function was measured by cavernous nerve stimulation. The penis was stained with antibodies to CD31, CD34, phosphohistone H3, phospho-endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor-A (VEGF-A). We also performed Western blot for phospho-eNOS and eNOS, and determined cyclic guanosine monophosphate (cGMP) concentration in the corpus cavernosum tissue. RESULTS: Significant improvement in erectile function was noted in diabetic mice treated with SVF at concentrations of 1 × 10(5) and 2 × 10(5) cells, which reached up to 82% of the control values. Local delivery of SVF significantly increased cavernous endothelial cell proliferation, eNOS phosphorylation, and cGMP expression compared with that in the untreated group and the PBS-treated diabetic group. Intracavernous injection of SVF increased cavernous VEGF-A expression and induced recruitment of CD34(+)CD31(-) progenitor cells. Some SVF underwent differentiation into cavernous endothelial cells. SVF-induced promotion of cavernous angiogenesis and erectile function was abolished in the presence of VEGF-Trap, a soluble VEGF-A neutralizing antibody. CONCLUSION: The results support the concept of cavernous endothelial regeneration by use of SVF as a curative therapy for diabetic ED.

Effects of Dietary Protein and Lipid Levels on Growth and Body Composition of Juvenile Far Eastern Catfish Silurus asotus.

A 3×2 factorial experiment was conducted to determine the effects of dietary protein and lipid levels on the growth and body composition of juvenile far eastern catfish. Six diets were formulated to contain three levels of protein (20%, 30% and 40%) and two levels of lipid (9% and 17%). Triplicate groups of fish (initial body weight of 7.6 g) were hand-fed to apparent satiation for 66 days. Final mean weight was improved with increasing dietary protein and lipid levels, and the highest final mean weight was observed in fish fed the 40/17 (% protein/% lipid) diet. No significant difference was observed in final mean weight for fish fed between 30/17 diet and 40/9 diet. Feed efficiency of fish fed the diets containing over 30% protein levels with 9% and 17% lipid levels were significantly higher than those of fish fed the 20% protein levels. Feed efficiency of fish fed the 30/17 diet was not significantly different from that of fish fed the 40/9 diet or 40/17 diet. Feed efficiency and protein efficiency ratio of fish fed the 20% protein diets with 17% lipid level were significantly higher than those of fish fed 9% lipid diet. Daily feed intake of fish tended to decrease with increasing dietary protein and lipid levels. Moisture content of whole body in fish fed the 9% lipid diets was significantly higher than that of fish fed the 17% lipid diets at the same protein level, but the opposite trends were found for crude lipid content. Significant effects of dietary lipid were observed for most fatty acids, according to their relative values in the diets. The results of this study suggest that the protein requirement for maximum growth of juvenile far eastern catfish may be higher than 40%, and an increase of dietary lipid level from 9% to 17% can improve growth and feed utilization.

Early sequential changes in bladder function after partial bladder outlet obstruction in awake sprague-dawley rats: focus on the decompensated bladder.

PURPOSE: We investigated bladder function, with special focus on initial functional changes, by objective report of decompensated bladder according to the percentage of residual urine volume to bladder capacity in awake, obstructed rats. MATERIALS AND METHODS: Thirty rats were randomly subjected to sham operations (n=10) or partial bladder outlet obstruction (BOO, n=20). Cystometric investigations were performed without anesthesia 1 or 2 weeks after BOO surgery. To reduce the influence of confounding factors in awake cystometry, we used simultaneous recordings of intravesical and intraabdominal pressures. Decompensated bladder was defined as the bladder with more than 20% of residual volume compared with bladder capacity. RESULTS: Compared with that in sham animals, basal pressure was elevated in both BOO groups. Threshold pressure was higher in the 2 week BOO (p<0.01) group. Compliance was decreased in the 1 week BOO group (p<0.01) and increased in the 2 week BOO group (p<0.001). Bladder capacity was not increased in the 1 week BOO group, but was increased in the 2 week BOO group (p<0.01). Decompensation was found in 62.5% of the 1 week BOO group and in 33.3% of the 2 week BOO group. CONCLUSIONS: From the earlier phase, the bladders exhibited serial changes in pressure and volume parameters, and decompensated bladders defined by the percentage of residual volume to bladder capacity could be seen. During the later phase, there was an increasing tendency of compensated bladders, accompanied by the bladders being enlarged and more compliant.

Regulation of apoptosis by modified naringenin derivatives in human colorectal carcinoma RKO cells.

Flavonoids are micronutrients that are widely detected in foods of plant origin and have been ascribed pharmacological properties. Several biological functions of flavonoids have been thus far identified, whereas there currently exists a lack of evidence to support the relationship between the structure-activity relationship and apoptosis-inducing activity. In an attempt to determine the importance of the OH group or substitution of the 5- or 7-carbon in the diphenylpropane skeleton of flavonoids, we selected 14 different flavonoids with different structures, particularly with regard to the 5- or 7-carbon, and found that naringenin treatment caused a slight decrease in the cell viability of the human colorectal carcinoma RKO cells. Next, in order to characterize the effects of specific substitutions of the 7-carbon of naringenin on apoptosis-regulatory activities, and in an attempt to develop anti-proliferative flavonoid derivatives that would be more effective against colon cancer, we originally synthesized several modified naringenin derivatives (MNDs) including 7-O-benzyl naringenin (KUF-1) and 7-O-(m-metoxybenzyl) naringenin (KUF-2). Treatment with KUF-1 or KUF-2 resulted in significant apoptosis-inducing effects concomitant with losses in mitochondrial membrane potential, caspase activation, intracellular ROS production, and sustained ERK activation. Our data show that KUF-1 or KUF-2 regulate the apoptosis of RKO cells via intracellular ROS production coupled with the concomitant activation of the ERK signaling pathway, thereby implying that hydroxylation or substitution at C7 is critical for the apoptosis-inducing activity of flavonoids.

Induction of apoptotic cell death by synthetic naringenin derivatives in human lung epithelial carcinoma A549 cells.

Although flavonoids, which are both qualitatively and quantitatively one of the largest groups of natural products, exhibit a variety of beneficial health effects, the exact molecular mechanism of the cellular activities is still not fully explained and there currently exists a lack of evidence for any relationship between the structure-activity relationship and apoptosis-inducing activity. In order to determine the importance of the OH group or substitution of the 5 or carbon-7 in the diphenylpropane skeleton of flavonoids, we originally synthesized several modified naringenin derivatives, including 7-O-benzyl naringenin (KUF-1) and 7-O-(MeO-L-Leu-D-Pro-carbonylmethyl) naringenin (KUF-7). Treatment with KUF-1 or KUF-7 resulted in significant apoptosis-inducing effects concomitant with chromatin condensation, caspase activation, and intracellular ROS production. Our data indicate that originally synthesized naringenin derivatives, KUF-1 and KUF-7 differentially regulate the apoptosis of A549 cells via intracellular ROS production coupled with the concomitant activation of the caspase cascade signaling pathway, thereby implying that hydroxylation or substitution at Carbon-7 is critical for the apoptosis-inducing activity of flavonoids.

The anti-apoptotic and anti-oxidant effect of eriodictyol on UV-induced apoptosis in keratinocytes.

Recently, considerable scientific and therapeutic interest has focused on the structure and functions of the flavonoids. In a previous study, we suggested that hydroxyl (OH) substitutions on specific carbons in the skeleton of the flavonoids might significantly affect their apoptosis-modulating properties. Here, to investigate the effect of various OH substitutions on their diphenylpropane (C6C3C6) skeleton carbons, we selected 10 different flavonoids and assessed their role on UV-induced apoptosis of human keratinocytes, the principal cell type of epidermis. The results showed that 5,7,3',4'-tetrahydroxylflavanone (eriodictyol) and 3,4'-dihydroxy flavone (3,4'-DHF) had a positive effect on cell proliferation of human HaCaT keratinocytes. Treatment with eriodictyol in particular resulted in significant suppression of cell death induced by ultraviolet (UV) light, a major skin-damaging agent. We found that eriodictyol treatment apparently reduced the percentage of apoptotic cells and the cleavage of poly(ADP-ribose) polymerase, concomitant with the repression of caspase-3 activation and reactive oxygen species (ROS) generation. The anti-apoptotic and anti-oxidant effects of eriodictyol were also confirmed in UV-induced cell death of normal human epidermal keratinocyte (NHEK) cells. Taken together, these findings suggest that eriodictyol can be used to protect keratinocytes from UV-induced damage, implying the presence of a complex structure-activity relationship (SAR) in the differential apoptosis-modulating activities of various flavonoids.

Interplay between PI3K/Akt and MAPK signaling pathways in DNA-damaging drug-induced apoptosis.

In order to elucidate the role of the mitogen-activated protein kinases, including JNK, p38 MAPK and ERK, as well as the survival-associated PI3K/Akt signaling pathway, in the response to chemotherapy, we have conducted a comparative study regarding the effects of doxorubicin on these pathways. Doxorubicin was determined to elicit the apoptosis of NIH3T3 cells in a dose-dependent manner. Prior to cell death, both Akt and p38 MAPK were transiently activated, and subsequently inactivated almost wholly, whereas ERK and JNK evidenced sustained activations in response to the drug treatment. The inhibition of PI3K/Akt and p38 MAPK both accelerated and enhanced doxorubicin-induced apoptosis and ERK inhibition apparently exerted negative effect on apoptosis. The modulation of PI3K/Akt activation by treatment of LY294002 or expression of Akt mutants such as Akt-DN or Myr-Akt exerted a significant effect on the activation of ERK1/2. We also observed that PI3K/Akt and sustained ERK activation were associated intimately with the etoposide-induced apoptosis. Taken together, our results clearly suggest that the differential regulation of the PI3K/Akt, ERK1/2, and p38 MAPK signaling pathways are crucial in the context of DNA-damaging drug-induced apoptosis, and this has compelled us to propose that the sustained activation of ERK1/2 pathway may be generally involved in the apoptosis induced by anticancer DNA-damaging drugs, including doxorubicin and etoposide.

Modulation of apoptosis in HaCaT keratinocytes via differential regulation of ERK signaling pathway by flavonoids.

The exact molecular mechanisms underlying the cellular effects associated with various flavonoids have yet to be fully explained. In the present study, we have administered several flavonoids to human HaCaT keratinocytes and determined that 3,4'-dihydroxy flavone (3,4'-DHF) exerts a slight stimulatory effect on cell growth, although other flavonoids, including kaempferol, quercetin, and isorhamnetin, exhibited growth inhibitory properties. 3,4'-DHF was found to exert an anti-apoptotic effect on etoposide-induced cell death of HaCaT keratinocytes. We were also able to determine that sustained ERK activation was intimately associated with the etoposide-induced apoptosis of HaCaT cells, and treatment with 3,4'-DHF induced a significant suppression of etoposide-induced ERK activation, concomitant with the repression of poly(ADP-ribose) polymerase or the cleavage of pro-caspase 3. ERK overexpression significantly overrode the anti-apoptotic function of 3,4'-DHF, but this was not true of ERK-DN. Moreover, treatment with 3,4'-DHF resulted in the protection of cells from H2O2-induced cell death and exerted an apparent suppressive effect on the stress-induced generation of reactive oxygen species (ROS). Finally, we showed that 3,4'-DHF almost completely abolished kaempferol-induced apoptosis, coupled with a concomitant suppression of both intracellular ROS generation and the activation of ERK. Taken together, our data clearly indicate that a host of phytochemicals, including etoposide and a variety of flavonoids, differentially regulate the apoptosis of human HaCaT keratinocytes via the differential modulation of intracellular ROS production, coupled with the concomitant activation of the ERK signaling pathway. According to these results, we are able to conclude the distinct structure-activity relationship between several flavonoids.