Inhibition of LNC EBLN3P Enhances Radiation-Induced Mitochondrial Damage in Lung Cancer Cells by Targeting the Keap1/Nrf2/HO-1 Axis.

Lung cancer remains the leading cause of cancer-related deaths in both women and men, claiming millions of lives worldwide. Radiotherapy is an effective modality for treating early-stage lung cancer; however, it cannot completely eradicate certain tumor cells due to their radioresistance. Radioresistance is commonly observed in conventionally fractionated radiotherapy, which can lead to treatment failure, metastasis, cancer recurrence, and poor prognosis for cancer patients. Identifying the underlying molecular mechanisms of radioresistance in lung cancer can promote the development of effective radiosensitizers, thereby improving patients' life expectancy and curability. In this study, we identified LNC EBLN3P as a regulator of lung cancer cell proliferation and radiosensitivity. The repression of LNC EBLN3P could increase ROS production and mitochondrial injury in NSCLC cells. In addition, knocking down LNC EBLN3P increased the binding of Nrf2 to Keap1, resulting in enhanced Nrf2 degradation, decreased translocation of Nrf2 to the nucleus, reduced expression of antioxidant protein HO-1, weakened cellular antioxidant capacity, and increased radiosensitivity of NSCLC cells. These findings suggest that targeting LNC EBLN3P could be a promising strategy for developing novel radiosensitizers in the context of conventional radiotherapy for NSCLC.

Evaluating Short-Term and Long-Term Risks Associated with Renal Artery Stenosis Position and Severity: A Hemodynamic Study.

Background: Moderate renal artery stenosis (50-70%) may lead to uncontrolled hypertension and eventually cause irreversible damage to renal function. However, the clinical criteria for interventional treatment are still ambiguous in this condition. This study investigated the impact of the position and degree of renal artery stenosis on hemodynamics near the renal artery to assess the short-term and long-term risks associated with this disease. Methods: Calculation models with different degrees of stenosis (50%, 60%, and 70%) located at different positions in the right renal artery were established based on the computed tomography angiography (CTA) of a personalized case. And computational fluid dynamics (CFD) was used to analyze hemodynamic surroundings near the renal artery. Results: As the degree of stenosis increases and the stenosis position is far away from the aorta, there is a decrease in renal perfusion. An analysis of the wall shear stress (WSS)-related parameters indicated areas near the renal artery (downstream of the stenosis and the entrance of the right renal artery) with potential long-term risks of thrombosis and inflammation. Conclusion: The position and degree of stenosis play a significant role in judging short-term risks associated with renal perfusion. Moreover, clinicians should consider not only short-term risks but also independent long-term risk factors, such as certain regions of 50% stenosis with adequate renal perfusion may necessitate prompt intervention.

Cytokeratin 13 Is a New Biomarker for the Diagnosis of Limbal Stem Cell Deficiency.

PURPOSE: The purpose of this study was to evaluate the expression of cytokeratin (K) 13 on the corneal surface and to validate its application in the diagnosis of limbal stem cell deficiency (LSCD). METHODS: This prospective comparative study included 26 corneal impression cytology (IC) specimens from patients diagnosed with LSCD. Twenty-three IC specimens from normal donors served as controls. K12 and K13 expression were detected on the IC specimens by immunohistochemistry study. The number of K12 + or K13 + cells in all areas of the IC was quantified using ImageJ software. RESULTS: The epithelial cells harvested from IC specimens from control corneas were all K12 + . In eyes with LSCD, K13 + and K12 + /K13 + cells accounted for 93.8% and 2.6%, respectively, in the cornea. In eyes with sectoral LSCD, the median number of K13 + cells in the clinically affected area was higher than that in the unaffected area (810.0 vs. 115.0 cells/mm 2 ; P < 0.001). No significant correlation was found between the LSCD severity and the number of K12 + cells (r = -0.284, P = 0.16) or K13 + cells (r = -0.011, P = 0.95). The presence of at least 16 K13 + cells/mm 2 was suggestive of LSCD. CONCLUSIONS: Identification of K13 + cells on IC specimens provides a simple and reliable method to detect conjunctival epithelial cells on the cornea. K13 is a marker for diagnosing LSCD and localizing the involved area in sectoral LSCD.

Approximate geodesic distance tree filter for cost aggregation.

The computation of the disparity for the pixels in the weak texture area has always been a difficult task in stereo vision. The non-local method based on a minimum spanning tree (MST) provides a solution to construct content-adaptive support regions to perform cost aggregation. However, it always introduces error disparity in slanted surfaces and is sensitive to noise and highly textural regions. The window-based methods are not effective for information dissemination. To overcome the problem mentioned above, this paper proposes an approximate geodesic distance tree filter, which utilizes geodesic distance as a pixels similarity metric and recursive techniques to perform the filtering process. The filtering process is performed recursively in four directions (namely from top-left, top-right, and vice versa), which make our filter with linear complexity. Our filter has advantages in the sense that: (1) the pixel similarity metric is approximated geodesic distance; (2) the computational complexity is linear to the image pixel. Due to these reasons, the proposed method can properly cope with cost aggregation in the textureless regions and preserve the boundary of disparity maps. We demonstrate the strength of our filter in several applications.

Collaborative semi-global stereo matching.

Efficiency and accuracy of semi-global matching (SGM) make it outperform many stereo matching algorithms and is widely used under challenging occasions. However, SGM only incorporates information along a scanline in each pass and lacks interaction between scanlines, resulting in streak artifacts in the disparity image. We introduce a local edge-aware filtering method to SGM to enhance the interaction of neighboring scanlines, since streak artifacts can be avoided. We use bilateral weights based on intensity similarity and spatial affinity between pixels to build connections among scanlines. In each pass, we recursively estimate the aggregated cost of SGM and compute the weighted average of aggregated costs for pixels in the orthogonal direction to obtain the output of our method along each scanline. As one-dimensional bilateral filtering is used in our method, the extra computation is linear to image resolution and label space, which is a small fraction of that needed by SGM. We present ablation studies using stereo pairs under both constrained and natural conditions to verify the effectiveness of our method. Extensive experiments on Middlebury and Karlsruhe Institute of Technology and Toyota Technology Institute datasets demonstrate that our method removes all streak artifacts, improves the quality of the disparity image, and outperforms many other non-local cost aggregation approaches.

Four-direction global matching with cost volume update for stereovision.

The accuracy and speed of semi-global matching (SGM) make it widely used in many computer vision problems. However, SGM often struggles in dealing with pixels in the homogeneous regions and also suffers from streak artefacts for weak smoothness constraints. Meanwhile, we observe that the global method usually fails in occluded areas. The disparities for occluded pixels are typically the average of the disparity of nearby pixels. The local method can propagate the information into occluded pixels with a similar color. In this paper, we propose a novel, to the best of our knowledge, four-direction global matching with a cost volume update scheme to cope with textureless regions and occlusion. The proposed method makes two changes in the recursive formula: a) the computation process considers four visited nodes to enforce more smooth constraints; b) the recursive formula integrates cost filtering to propagate reliable information farther in nontextured regions. Thus, our method can inherit the speed of SGM, properly avoid streaking artefacts, and deal with the occluded pixel. Extensive experiments in stereo matching on Middlebury demonstrate that our method outperforms typical SGM-based cost aggregation approaches and other state-of-the-art local methods.

Tianshengyuan-1 (TSY-1) regulates cellular Telomerase activity by methylation of TERT promoter.

Telomere and Telomerase have recently been explored as anti-aging and anti-cancer drug targets with only limited success. Previously we showed that the Chinese herbal medicine Tianshengyuan-1 (TSY-1), an agent used to treat bone marrow deficiency, has a profound effect on stimulating Telomerase activity in hematopoietic cells. Here, the mechanism of TSY-1 on cellular Telomerase activity was further investigated using HL60, a promyelocytic leukemia cell line, normal peripheral blood mononuclear cells, and CD34+ hematopoietic stem cells derived from umbilical cord blood. TSY-1 increases Telomerase activity in normal peripheral blood mononuclear cells and CD34+ hematopoietic stem cells with innately low Telomerase activity but decreases Telomerase activity in HL60 cells with high intrinsic Telomerase activity, both in a dose-response manner. Gene profiling analysis identified Telomerase reverse transcriptase (TERT) as the potential target gene associated with the TSY-1 effect, which was verified by both RT-PCR and western blot analysis. The ß-galactosidase reporter staining assay showed that the effect of TSY-1 on Telomerase activity correlates with cell senescence. TSY-1 induced hypomethylation within TERT core promoter in HL60 cells but induced hypermethylation within TERT core promoter in normal peripheral blood mononuclear cells and CD34+ hematopoietic stem cells. TSY-1 appears to affect the Telomerase activity in different cell lines differently and the effect is associated with TERT expression, possibly via the methylation of TERT promoter.

Effect of Tianshengyuan-1 (TSY-1) on telomerase activity and hematopoietic recovery - in vitro, ex vivo, and in vivo studies.

Aplastic anemia is a heterogeneous disorder of bone marrow failure syndrome. Accumulating evidence indicates that both acquired and congenital aplastic anemia is linked to telomerase activity and telomere length. Chinese herbal medicine Tianshengyuan-1 (TSY-1), a liquid extraction of multiple Chinese herbs, appears to stimulate hematopoiesis in patients with bone marrow deficiencies; however, the exact mechanism of action remains unclear. In this study, we investigated the effect of TSY-1 on telomere length and telomerase activity. We first investigated the effects of TSY on in vitro cultured cell lines including CD34+ hepatic stem cells and CD4+/CD8- Jurkat cells. An immune-mediated murine aplastic anemia model and human samples, including peripheral blood samples of 4 healthy donors and bone marrow hematopoietic cells from 4 patients with hypocellular myelodysplastic syndrome (MDS), were also used to test the efficacy of TSY on hematopoiesis, telomerase activity and telomere length. Our results indicated that TSY-1 increased the telomerase activity and telomere length in a dose-response manner in vitro, in vivo, and in human samples including 3 of 4 healthy individuals and 3 of 4 bone marrow samples from MDS patients. In immune-mediated murine aplastic anemia model, TSY-1 activity on Telomere length was parallel to the significant increasing of the RBC, hemoglobin, hematocrit, and platelet count in peripheral blood, increasing of CD34+ cell count and hematopoiesis, and decreasing of fatty infiltration in bone marrow samples. Our study demonstrated that TSY-1 may exert its effects by modulating telomerase activity of hematopoietic cells. Further studies are warranted to explore the precise molecular mechanisms of how TSY-1 regulates telomerase activity and telomere length, and also to test the TSY-1 in randomized control trials.

PIAS1 regulates breast tumorigenesis through selective epigenetic gene silencing.

Epigenetic gene silencing by histone modifications and DNA methylation is essential for cancer development. The molecular mechanism that promotes selective epigenetic changes during tumorigenesis is not understood. We report here that the PIAS1 SUMO ligase is involved in the progression of breast tumorigenesis. Elevated PIAS1 expression was observed in breast tumor samples. PIAS1 knockdown in breast cancer cells reduced the subpopulation of tumor-initiating cells, and inhibited breast tumor growth in vivo. PIAS1 acts by delineating histone modifications and DNA methylation to silence the expression of a subset of clinically relevant genes, including breast cancer DNA methylation signature genes such as cyclin D2 and estrogen receptor, and breast tumor suppressor WNT5A. Our studies identify a novel epigenetic mechanism that regulates breast tumorigenesis through selective gene silencing.

A double-blind, randomized, neoadjuvant study of the tissue effects of POMx pills in men with prostate cancer before radical prostatectomy.

Pomegranates slow prostate cancer xenograft growth and prolong prostate-specific antigen (PSA) doubling times in single-arm human studies. Pomegranates' effects on human prostate tissue are understudied. We hypothesized that orally administered pomegranate extract (POMx; Pom Wonderful) would lower tissue 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative stress biomarker. Seventy men were randomized to two tablets, POMx or placebo, daily up to four weeks before radical prostatectomy. Tissue was analyzed for intraprostatic urolithin A, a pomegranate metabolite, benign and malignant 8-OHdG, and cancer pS6 kinase, NF-κB, and Ki67. Primary endpoint was differences in 8-OHdG, and the study was powered to detect 35% reduction. POMx was associated with 16% lower benign tissue 8-OHdG (P = 0.095), which was not statistically significant. POMx was well tolerated with no treatment-related withdrawals. There were no differences in baseline clinicopathological features between arms. Urolithin A was detected in 21 of the 33 patients in the POMx group versus 12 of the 35 in the placebo group (P = 0.031). Cancer pS6 kinase, NF-κB, Ki67, and serum PSA changes were similar between arms. POMx before surgery results in pomegranate metabolite accumulation in prostate tissues. Our primary endpoint in this modest-sized short-term trial was negative. Future larger longer studies are needed to more definitively test whether POMx reduces prostate oxidative stress, as well as further animal testing to better understand the multiple mechanisms through which POMx may alter prostate cancer biology.

Intraductal therapy of ductal carcinoma in situ: a presurgery study.

INTRODUCTION: Ductal carcinoma in situ (DCIS) is a noninvasive breast cancer wherein malignant cells are confined within a ductal lobular unit. Although less than half the cases of DCIS will progress to invasive disease, most women are treated aggressively with surgery, radiation, and/or hormone therapy due to the inability to clinically evaluate the extent and location of the disease. Intraductal therapy, in which a drug is administered directly into the mammary duct through the nipple, is a promising approach for treating DCIS, but the feasibility of instilling drug into a diseased duct has not been established. PATIENTS AND METHODS: Four to 6 weeks before their scheduled surgery, 13 women diagnosed with DCIS were subjected to cannulation of the affected duct. After both the absence of perforation and presence of dye in the duct were confirmed by ductogram, pegylated liposomal doxorubicin was instilled. Histopathologic assessment was performed after surgery to assess the treatment effects. RESULTS: Of the 13 women enrolled in the study, 6 had their DCIS duct successfully cannulated without perforation and instilled with the drug. The treatment was well tolerated, and no serious adverse events have been reported. Biomarker studies indicated a general decrease in Ki-67 levels but an increase in annexin-1 and 8-hydroxydeoxyguanosine in the lumen of DCIS-containing ducts, which suggests a local response to pegylated liposomal doxorubicin treatment. CONCLUSIONS: Intraductal therapy offers a nonsurgical strategy to treat DCIS at the site of disease, potentially minimizing the adverse effects of systemic treatment while preventing development of invasive cancer.

Green tea inhibits cycolooxygenase-2 in non-small cell lung cancer cells through the induction of Annexin-1.

Elevated cyclooygenase-2 (COX-2) expression is frequently observed in human non-small cell lung cancer (NSCLC) and associated with poor prognosis, indicating critical involvement of the inflammatory pathway in lung carcinogenesis. Recently, we found that green tea extract (GTE) induced Annexin-1 (ANX1) in the lung adenocarcinoma A549 cells. ANX1 is a glucocorticoid-inducible 37kDa protein involved in a wide range biological function and is an important anti-inflammatory mediator. The present study further examines the interplay between the expressions and production of ANX1, COX-2, phospholipase A(2) (cPLA(2)) and prostaglandin E(2) (PGE(2)) following the treatment of NSCLC cell lines with GTE. We found that GTE induced ANX1 and inhibited COX-2 expression in lung cancer A549, H157 and H460 cell lines. Addition of pro-inflammatory cytokine IL-1ß diminished GTE-induced ANX1. Silence of ANX1 in cells abrogates the inhibitory activity on COX-2, indicating that the anti-inflammatory activity of GTE is mediated at least partially by the up-regulation of ANX1. However, differential pattern of inhibitory effects of ANX1 on cPLA(2) expression was observed among various cell types, suggesting that the anti-inflammatory activity mediated by ANX1 is cell type specific. Our study may provide a new mechanism of GTE on the prevention of lung cancer and other diseases related to inflammation.

Green tea extract selectively targets nanomechanics of live metastatic cancer cells.

Green tea extract (GTE) is known to be a potential anticancer agent (Yang et al 2009 Nat. Rev. Cancer 9 429-39) with various biological activities (Lu et al 2005 Clin. Cancer Res. 11 1675-83; Yang et al 1998 Carcinogenesis 19 611-6) yet the precise mechanism of action is still unclear. The biomechanical response of GTE treated cells taken directly from patient's body samples was measured using atomic force microscopy (AFM) (Binnig et al 1986 Phys. Rev. Lett. 56 930). We found significant increase in stiffness of GTE treated metastatic tumor cells, with a resulting value similar to untreated normal mesothelial cells, whereas mesothelial cell stiffness after GTE treatment is unchanged. Immunofluorescence analysis showed an increase in cytoskeletal-F-actin in GTE treated tumor cells, suggesting GTE treated tumor cells display mechanical, structural and morphological features similar to normal cells, which appears to be mediated by annexin-I expression, as determined by siRNA analysis of an in vitro cell line model. Our data indicates that GTE selectively targets human metastatic cancer cells but not normal mesothelial cells, a finding that is significantly advantageous compared to conventional chemotherapy agents.

White tea extract induces apoptosis in non-small cell lung cancer cells: the role of peroxisome proliferator-activated receptor-{gamma} and 15-lipoxygenases.

Emerging preclinical data suggests that tea possess anticarcinogenic and antimutagenic properties. We therefore hypothesize that white tea extract (WTE) is capable of favorably modulating apoptosis, a mechanism associated with lung tumorigenesis. We examined the effects of physiologically relevant doses of WTE on the induction of apoptosis in non-small cell lung cancer cell lines A549 (adenocarcinoma) and H520 (squamous cell carcinoma) cells. We further characterized the molecular mechanisms responsible for WTE-induced apoptosis, including the induction of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and the 15-lipoxygenase (15-LOX) signaling pathways. We found that WTE was effective in inducing apoptosis in both A549 and H520 cells, and inhibition of PPAR-gamma with GW9662 partially reversed WTE-induced apoptosis. We further show that WTE increased PPAR-gamma activation and mRNA expression, concomitantly increased 15(S)-hydroxy-eicosatetraenoic acid release, and upregulated 15-LOX-1 and 15-LOX-2 mRNA expression by A549 cells. Inhibition of 15-LOX with nordihydroguaiaretic acid (NGDA), as well as caffeic acid, abrogated WTE-induced PPAR-gamma activation and upregulation of PPAR-gamma mRNA expression in A549 cells. WTE also induced cyclin-dependent kinase inhibitor 1A mRNA expression and activated caspase-3. Inhibition of caspase-3 abrogated WTE-induced apoptosis. Our findings indicate that WTE is capable of inducing apoptosis in non-small cell lung cancer cell lines. The induction of apoptosis seems to be mediated, in part, through the upregulation of the PPAR-gamma and 15-LOX signaling pathways, with enhanced activation of caspase-3. Our findings support the future investigation of WTE as an antineoplastic and chemopreventive agent for lung cancer.

AFM-based analysis of human metastatic cancer cells.

Recently biomechanics of cancer cells, in particular stiffness or elasticity, has been identified as an important factor relating to cancer cell function, adherence, motility, transformation and invasion. We report on the nanomechanical responses of metastatic cancer cells and benign mesothelial cells taken from human body cavity fluids using atomic force microscopy. Following our initial study (Cross et al 2007 Nat. Nanotechnol. 2 780-3), we report on the biophysical properties of patient-derived effusion cells and address the influence of cell morphology on measured cell stiffness. Using a cytocentrifugation method, which yields morphologically indistinguishable cells that can be prepared in 1 min and avoids any possible artifacts due to 12 h ex vivo culture, we find that metastatic tumor cells are more than 80% softer than benign cells with a distribution over six times narrower than that of normal cells. Consistent with our previous study, which yielded distinguishable cell populations based on ex vivo growth and morphological characteristics, our results show it is unlikely that morphology alone is sufficient to explain the difference in elastic moduli for these two cell types. Moreover, analysis of non-specific cell adhesion inherent to tumor and normal cells collected from patients show surface adhesion of tumor cells is ∼33% less adhesive compared to that of normal cells. Our findings indicate that biomechanical-based functional analysis may provide an additional platform for cytological evaluation and diagnosis of cancer in the future.

Nanomechanical analysis of cells from cancer patients.

Change in cell stiffness is a new characteristic of cancer cells that affects the way they spread. Despite several studies on architectural changes in cultured cell lines, no ex vivo mechanical analyses of cancer cells obtained from patients have been reported. Using atomic force microscopy, we report the stiffness of live metastatic cancer cells taken from the body (pleural) fluids of patients with suspected lung, breast and pancreas cancer. Within the same sample, we find that the cell stiffness of metastatic cancer cells is more than 70% softer, with a standard deviation over five times narrower, than the benign cells that line the body cavity. Different cancer types were found to display a common stiffness. Our work shows that mechanical analysis can distinguish cancerous cells from normal ones even when they show similar shapes. These results show that nanomechanical analysis correlates well with immunohistochemical testing currently used for detecting cancer.

Annexin-I as a potential target for green tea extract induced actin remodeling.

Using a multistep human urothelial model, we previously showed that green tea extract (GTE) selectively modulates actin remodeling in transformed cells (MC-T11), which resulted in increased cell adhesion and reduced cell motility (Lu et al., Clin Cancer Res 2005;11:1675-83). This study further analyzed which actin binding proteins (ABPs) might be involved in this process. Proteomic profiles of GTE treated and untreated MC-T11 cells using two-dimensional gel electrophoresis coupled with liquid chromatography tandem mass spectrometry (LC/MS/MS) and matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) identified 20 GTE-induced proteins. Among them, 3 were ABPs (tropomodulin, cofilin and annexin-I), and only annexin-I showed a dose- and time-dependent expression. The increased annexin-I correlated with actin remodeling, and was the result of transcription level up-regulation, as determined by RT-PCR, pull-down immunoblot and siRNA analyses. 5-Azacytidine, a DNA methylation inhibitor, exhibited no effect on annexin-I expression when used alone, but had an additive effect for GTE-induced annexin-I expression. Immunohistochemistry of bladder cancer tissue array showed a decrease of annexin-I expression in carcinoma in situ and low grade papillary carcinoma (n = 32, 0% positive) compared to nontumor urothelium (n = 18, 89% positive) (p < 0.001 by Fisher exact test), but increased in some (6 of 15, 40%) high-grade tumors. Together, GTE induced annexin-I expression plays a role in regulating actin remodeling and decreased annexin-I expression is a common event in early stage of bladder cancer development.

Dendritic cell surface calreticulin is a receptor for NY-ESO-1: direct interactions between tumor-associated antigen and the innate immune system.

How the immune system recognizes endogenously arising tumors and elicits adaptive immune responses against nonmutated tumor-associated Ags is poorly understood. In search of intrinsic factors contributing to the immunogenicity of the tumor-associated Ag NY-ESO-1, we found that the NY-ESO-1 protein binds to the surface of immature dendritic cells (DC), macrophages, and monocytes, but not to that of B cells or T cells. Using immunoprecipitation coupled with tandem mass spectrometry, we isolated DC surface calreticulin as the receptor for NY-ESO-1. Calreticulin Abs blocked NY-ESO-1 binding on immature DC and its cross-presentation to CD8+ T cells in vitro. Calreticulin/NY-ESO-1 interactions provide a direct link between NY-ESO-1, the innate immune system, and, potentially, the adaptive immune response against NY-ESO-1.

Effect of an epidermal growth factor receptor tyrosine kinase inhibitor on actin remodeling in an in vitro bladder cancer carcinogenesis model.

Alteration of actin remodeling is a marker of malignant-associated field defect and a potential surrogate biomarker for chemoprevention trials. We tested erlotinib, a specific tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR), on actin remodeling in a bladder carcinogenic model consisting of untransformed HUC-PC cells and transformed MC-T11 cells, both derived from the same normal human urothelial clone immortalized by SV40. Erlotinib had a selective growth inhibitory and actin remodeling effect on MC-T11 cells over HUC-PC cells, as examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and immunofluorescence labeling with laser scan cytometer analysis, respectively. The IC(50) of untransformed HUC-PC cells was significantly higher than that of transformed MC-T11 cells (P < 0.05, t test). The actin remodeling effect was more prominent at lower dosage levels (1/8-1/4 of IC(50)), which was accompanied by an increased cell adhesion and decreased motility. At higher dosage levels (1/2 of IC(50)), erlotinib induced a decreased adhesion and anoikis (detachment-associated apoptosis). The transformed MC-T11, but not HUC-PC, showed a weak constitutive EGFR phosphorylation activity, which was inhibited by erlotinib in a dose-response manner. However, on epidermal growth factor stimulation, both cell lines showed a similar dose-response inhibitory effect on phosphorylated EGFR and mitogen-activated protein kinase (MAPK; P44/P42) activities, and MAPK inhibitor PD98059 showed no specific effect on erlotinib-induced actin remodeling, suggesting that pathways other than MAPK (P44/P42) may be responsible for erlotinib-induced actin remodeling. The findings provide evidence to support erlotinib-based bladder cancer chemoprevention and using actin remodeling as a marker for erlotinib-based intervention trials.

Green tea extract modulates actin remodeling via Rho activity in an in vitro multistep carcinogenic model.

Alteration of actin polymerization and loss of actin filaments is a marker of cellular dedifferentiation and early malignant transformation. To study this phenomenon, an in vitro human urothelial model consisting of two cell lines, HUC-PC and MC-T11, were incorporated into the study design. These two cell lines have different malignant transformation potential. The effect of green tea extract (GTE), a potential anticancer agent, on actin remodeling was investigated. Upon exposure to the carcinogen 4-aminobiphenyl (4-ABP), the untransformed HUC-PC undergoes malignant transformation whereas the transformed MC-T11 progresses from noninvasive to invasive tumor. GTE induces actin polymerization in MC-T11 cells in a dose-responsive manner, but this effect is less obvious in the untransformed, more differentiated HUC-PC cells, which natively have higher actin polymerization status. In contrast, GTE antagonizes carcinogen 4-ABP induced actin depolymerization and stress fiber disruption in HUC-PC cells. In MC-T11 cells, GTE inhibits 4-ABP induced motility by increasing cell adhesion and focal adhesion complex formation. The effect of GTE on actin remodeling seems to be mediated by the stimulation of small GTP-binding protein Rho activity, because C3 exoenzyme, a specific inhibitor for Rho, blocks GTE-mediated Rho activation and stress fiber formation in MC-T11 cells. This study shows that GTE exerts an effect on cytoskeletal actin remodeling and provides further support for the use of GTE as a chemopreventive agent.