Expression of Wnt11 and Rock2 protein with clinical characteristics of esophageal squamous cell carcinoma in Kazakh and Han patients

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most malignancies with a very poor outcome in China. Wnt11 and Rock2, new identified proteins highly associated with metastasis of many cancers, which were never reported in esophageal squamous cell carcinoma (ESCC). Here we measured the expression levels of Wnt11 and Rock2 in tissues from 265 patients with ESCC. Immunohistochemical staining was employed to detect the correlation of Wnt11 and Rock2 expression with clinicopathological features.

METHODS

The expression of Wnt11 and Rock2 was detected by immunohistochemistry in esophageal squamous cell carcinomas and normal esophageal tissues. A chi-square test was used to assess the statistical significance of the correlations between Wnt11, Rock2 expression and different clinicopathological parameters, respectively.

RESULTS

The high-expression of Wnt11 and Rock2 was observed in ESCCs. Seventy-five cases of ESCC (51.7%) showed a positive expression of Wnt11, which indicated a significant association with the AJCC stage (P=0.007). Ninety-eight cases of ESCC (65.5%) showed a positive expression of Rock2, which indicated a significant association with ethnic background. There were no close correlations between Rock2 expression and gender, tumor location, AJCC stage, lymph node metastasis. Specifically, the expression of Rock2 was significantly different between Hans and Kazaks ethnicities (P=0.000). In Kaplan-Meier curve analysis, no significant correlation was observed between the expression of Wnt11, Rock-2 and the poor prognosis of ESCCs.

CONCLUSION

Our finding suggests that the over-expression of Rock2 may play an important role in the carcinogenesis and progression, and may become a new underlying molecular marker in the diagnosis and treatment in ESCC.

Using carboxyfluorescein diacetate succinimidyl ester to monitor intracellular protein glycation

Protein glycation is a ubiquitous process involved in vascular complications observed in diabetes. Glyoxal (GO), an intracellular reactive oxoaldehyde that is one of the most potent glycation agents, readily reacts with amines present on proteins to produce the lysine-derived adduct carboxymethyllysine, which is a prevalent advanced glycation end-product (AGE). Our group previously showed that cell exposure to GO leads to an alteration in the cell contractile activity that could occur as a result of the glycation of various proteins regulating the cell contractile machinery. Here, we measured the extent of glycation on three functionally distinct proteins known to participate in cell contraction and cytoskeletal organization-Rho-kinase (ROCK), actin, and gelsolin (GSN)-using an assay based on the reaction of the cell membrane-permeable fluorescent probe carboxyfluorescein diacetate succinimidyl ester (CFDA-SE), which reacts with primary amine groups of proteins. By combining CFDA-SE fluorescence and Western blot detection, we observed (following GO incubation) increased glycation of actin and ROCK as well as an increased interaction between actin and GSN as observed by co-immunoprecipitation. Thus, we conclude that the use of the fluorescent probe CFDA-SE offers an interesting alternative to perform a comparative analysis of the extent of intracellular protein glycation in live cells.

Actomyosin-mediated cellular tension drives increased tissue stiffness and β-catenin activation to induce epidermal hyperplasia and tumor growth

Tumors and associated stroma manifest mechanical properties that promote cancer. Mechanosensation of tissue stiffness activates the Rho/ROCK pathway to increase actomyosin-mediated cellular tension to re-establish force equilibrium. To determine how actomyosin tension affects tissue homeostasis and tumor development, we expressed conditionally active ROCK2 in mouse skin. ROCK activation elevated tissue stiffness via increased collagen. β-catenin, a key element of mechanotranscription pathways, was stabilized by ROCK activation leading to nuclear accumulation, transcriptional activation, and consequent hyperproliferation and skin thickening. Inhibiting actomyosin contractility by blocking LIMK or myosin ATPase attenuated these responses, as did FAK inhibition. Tumor number, growth, and progression were increased by ROCK activation, while ROCK blockade was inhibitory, implicating actomyosin-mediated cellular tension and consequent collagen deposition as significant tumor promoters.

RhoA/ROCK1 signaling regulates stress granule formation and apoptosis

Cells form stress granules (SGs), in response to unfavorable environments, to avoid apoptosis, but it is unclear whether and how SG formation and cellular apoptosis are coordinately regulated. In this study we detected the small GTPase, Ras homolog gene family member A (RhoA), and its downstream kinase, Rho-associated, coiled-coil containing protein kinase 1 (ROCK1), in SG, and found that their stress-induced activities were important for SG formation and subsequent global translational repression. Importantly, only activated RhoA and ROCK1 were sequestered into SG. Sequestration of activated ROCK1 into SG prevented ROCK1 from interacting with JNK-interacting protein 3 (JIP-3) and its activation of c-Jun N-terminal kinase (JNK), a pathway triggering apoptosis, thereby protecting cells from apoptosis. This study identifies a specific signaling pathway, mediated by RhoA and ROCK1, which determines cell fate by promoting SG formation or initiating apoptosis during stress.

A Rho-associated kinase mitigates reperfusion-induced change in the shape of cardiac capillary endothelial cells in situ

OBJECTIVE

We have previously demonstrated that ischaemia and reperfusion of the myocardium alter capillary dimensions and endothelial cell shape and that these changes are likely to be effected by the actomyosin contractile system in endothelial cells. Rho GTPases are involved in the regulation of cytoskeletal re-organization and in cell contraction. Rho-associated kinase regulates the sensitivity of myosin light chain to Ca(2+) in smooth muscle but not in cardiac or skeletal muscle myocytes. This study investigated the role of Rho-associated kinase in endothelial cell shape change induced by cardiac ischaemia and reperfusion. The role of Rho proteins in endothelial cell shape change in situ in the myocardial capillary bed has to date not been investigated.

METHODS

Ischaemia and reperfusion were induced in Langendorff perfused rat hearts at constant flow. Electron microscopy and immunofluorescence studies localized the beta Rho-associated kinase isotype in capillary endothelial cells. Whole capillary and luminal cross-section areas, luminal and abluminal membrane lengths were measured to monitor changes in cell dimensions. We used a ROCK inhibitor, Y-27632, to investigate the role of this protein in endothelial cell shape change.

RESULTS

ROCK1 localized primarily to intracellular membranes in endothelial cells. Morphometric analysis and a study of capillary lumen resin casts demonstrated that inhibition of the activity of this kinase with Y-27632 ablated the change in shape of endothelial cells induced by ischaemia and reperfusion.

CONCLUSION

These results suggest that ROCK1 is involved in cardiac capillary endothelial cell shape change in situ and that targeting the contractile system in this way may be useful in ameliorating reperfusion injury.