Impact of Caveolin-1 Expression on the Prognosis of Transitional Cell Carcinoma of the Upper Urinary Tract

This study aimed to investigate the relationship of caveolin-1 expression with prognosis in patients with transitional cell carcinoma of the upper urinary tract (TCCUUT). Formalin-fixed, paraffin-embedded tissue sections of TCC-UUT from 98 patients, who had undergone radical nephroureterectomy, were stained immunohistochemically using antibodies against caveolin-1. The expression pattern of caveolin- 1 was compared with the clinicopathological variables. The caveolin-1 expression was significantly correlated with T stage (p<0.001) and grade (p=0.036). The survival rate of patients with caveolin-1 positive tumors was significantly lower than that of patients with caveolin-1 negative tumors (p<0.0001). The univariate analyses identified T stage, grade, and caveolin-1 expression as significant prognostic factors for cancer-specific survival, whereas the multivariate analyses indicated that T stage and caveolin-1 expression were independent prognostic factors. These results show that the increased expression of caveolin-1 is associated with tumor progression and poor prognosis in TCC-UUT, suggesting that caveolin-1 may play an important role in the progression of TCC-UUT.

Exercise type and muscle fiber specific induction of caveolin-1 expression for insulin sensitivity of skeletal muscle

It is well known that exercise can have beneficial effects on insulin resistance by activation of glucose transporter. Following up our previous report that caveolin-1 plays an important role in glucose uptake in L6 skeletal muscle cells, we examined whether exercise alters the expression of caveolin-1, and whether exercise-caused changes are muscle fiber and exercise type specific. Fifity week-old Sprague Dawley (SD) rats were trained to climb a ladder and treadmill for 8 weeks and their soleus muscles (SOL) and extensor digitorum longus muscles (EDL) were removed after the last bout of exercise and compared with those from non-exercised animals. We found that the expression of insulin related proteins and caveolins did not change in SOL muscles after exercise. However, in EDL muscles, the expression of insulin receptor beta (IRbeta) and glucose transporter-4 (GLUT-4) as well as phosphorylation of AKT and AMPK increased with resistance exercise but not with aerobic exercise. Also, caveolin-1 and caveolin-3 increased along with insulin related proteins only in EDL muscles by resistance exercise. These results suggest that upregulation of caveolin-1 in the skeletal muscle is fiber specific and exercise type specific, implicating the requirement of the specific mode of exercise to improve insulin sensitivity.

Gamma-ray irradiation stimulates the expression of caveolin-1 and GFAP in rat spinal cord: a study of immunoblot and immunohistochemistry

We studied the expression of caveolin-1 in the spinal cords of rats using 60Co gamma-ray irradiation (single dose of 8 Gray (Gy)) in order to determine the possible involvement of caveolin-1 in the tissues of the central nervous system after irradiation. Spinal cords sampled at days 1, 4, and 9 post-irradiation (PI) (n = 5 per each time point) were analyzed by Western blot and immunohistochemistry. Western blot analysis showed that the expression of caveolin-1 was significantly increased at day 1 PI (p < 0.05), and returned to the level of normal control rats on days 4 and 9 PI. Immunohistochemistry showed that caveolin-1 immunoreactivity was enhanced in some glial cells, vascular endothelial cells, and neurons in the spinal cords. The increased expression of glial fibrillary acidic protein (GFAP), a marker for an astroglial reaction, was consistent with that of caveolin-1. In addition, caveolin-1 was co-localized in hypertrophied GFAP-positive astrocytes. Taking all these facts into consideration, we postulate that irradiation induces the increased expression of caveolin-1 in cells of the central nervous system, and that its increased expression in astrocytes may contribute to hypertrophy of astrocytes in the spinal cord after irradiation. The precise role of caveolin-1 in the spinal cords should be studied further.