類胰島素生長因子I(IGF-I)對細胞之生長發育有重要的調節作
用。在許多癌細胞株中,IGF-I也扮演自身刺激(autocrine)的
角色。為分析IGF-I在腫瘤形成過程中的變異情形,本論文測試
了非細小肺癌細胞株(NSCLC)及肺癌腦轉移細胞株(H226B),探
討IGF-I多.blkksq..blksq.及IGF-I與其受體(IGF-I R)基因之
表現情形。由 RT-PCR 中,我們偵測到實驗所用的二種非細小
肺癌細胞株(包括巨大細胞株H460及鱗細胞株H226)僅有極少量
IGF-I表現,但肺癌腦轉移細胞株則表現大量的 IGF-ImRNA。在
IGF-I R方面,所有細胞株均有相近之IGF-I R mRNA表現,由Nor-
thern blot也證實了這個發現。利用IGF-I R單株抗體(.alpha.
IR3)作細胞增殖試驗,H226B之生長會受.alpha.IR3抑制,而H226
所受之影響則較小。以ELISA測定細胞條件培養液中IGF-I量,
發現二者均只分泌少量IGF-I。以外加IGF-I處理細胞,二者均
未發現增殖反應。這些結果顯示出肺癌腦轉移細胞株會分泌IGF-
I,調節自身的生長;IGF-I之autocrine機制在肺癌細胞轉移過程
中所扮演的角色趨於重要。

Insulin-like growth factor I (IGF-I) is impor-
tant in the regulation of cell growth and develop
ment. IGF-I functions as an autocrine growth stim
ulus in many cancer cell lines. In order to ana-
lyze the function of IGF-I in the process of tumor
progression, IGF-I, its receptor gene expression
and peptide secretion were examined in non-small-
cell lung cancer cell lines (NSCLC) and the brain
metastatic variant (H226B). RT-PCR (Reverse trans
criptase polymerase chain reaction) revealed that,
compared to two NSCLC cell lines (H226 and H460),
H226B expressed enhanced level of IGF-I gene. All
cell lines expressed same levels of IGF-I R gene
as demonstrated by RT-PCR. Northern blot analysis
confirmed the finding. In colorimetric metabolic
MTT assay, both H226 and H226B didn't react mito-
genically to exogenous IGF-I. It was also found
that αIR3, an IGF-I R specific antibody,inhibited
the growth of H226B. We detected immunoreactive
IGF-I in the conditioned medium of H226 and H226B
by ELISA. Both cell lines secreted low levels of
IGF-I.These results suggest that IGF-I is critical
in the regulation of cell growth of H226B . The
tumor progression of brain metastasis is regulated
by IGF-I-mediated autocrine mechanism.
Insulin-like growth factor I (IGF-I) is impor-