Gene expression of TGF-alpha, EGF and IL-6 in cultured renal tubular cells and renal cell carcinoma.
BACKGROUND
Renal cell carcinoma (RCC) is thought to arise from the renal tubular cells (RTC). Assuming that proliferating RTC imply a premalignant change of RTC into RCC, messenger RNA expressions of growth factors in cultured RTC were compared to both cultured and frozen noncultured RCC.


METHODS
The expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), EGF receptor (EGFR) and interleukin-6 (IL-6) were studied in surgically obtained RCC (n = 17), cultured RCC (n = 10), and autologous cultured RTC (n = 15). Quantitation of the PCR product was performed using a computer image analyzer which evaluated the intensity of each cytokine relative to beta-actin.


RESULTS
TGF-alpha, EGFR and IL-6 were detected in most of the cultured RTC, and both cultured and noncultured RCC were also expressed at high levels. In contrast to a high positivity of TGF-alpha, EGF was not strongly positive in all specimens.


CONCLUSIONS
Our results show that there is a predominant autocrine production of TGF-alpha in RCC and RTC, suggesting that TGF-alpha plays a distinct role in the proliferation of these cells. These studies also indicate that the mechanisms of proliferation and cytokine production of RCC and RTC are similar.
Aoyagi
T
T
Department of Urology, National Defense Medical College, Saitama, Japan.
Takishima
K
K
Hayakawa
M
M
Nakamura
H
H
D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D004815:Epidermal Growth Factor / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics*; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology; D007684:Kidney Tubules / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D016211:Transforming Growth Factor alpha / Q000096:biosynthesis / Q000235:genetics*; D014407:Tumor Cells, Cultured
D015850:Interleukin-6; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor