SummaryAAA domain-containing 3A (ATAD3A) is a member of the AAA-ATPase family. Three forms of ATAD3 have been identified: ATAD3A, ATAD3B and ATAD3C. In this study, we examined the type and expression of ATAD3 in lung adenocarcinoma (LADC). Expression of ATAD3A was detected by reverse transcription-polymerase chain reaction, immunoblotting, immunohistochemistry and confocal immunofluorescent microscopy. Our results show that ATAD3A is the major form expressed in LADC. Silencing of ATAD3A expression increased mitochondrial fragmentation and cisplatin sensitivity. Serum deprivation increased ATAD3A expression and drug resistance. These results suggest that ATAD3A could be an anti-apoptotic marker in LADC.
Background & Aims
Early reports suggested androgen/androgen receptor (AR) signals promote hepatocarcinogenesis. However, all antiandrogen clinical trials failed in advanced hepatocellular carcinoma (HCC) without reasonable explanations. We have examined AR functions in HCC cancer metastasis in this study.
Methods
We examined hepatic AR roles in HCC metastasis by comparing liver hepatocyte AR knockout and wildtype in carcinogen-induced HCC mouse model. We examined tumor histology, cancer metastatic risks, and cancer survival in vivo, as well as cell anoikis and migration using primary hepatic tumor culture in vitro. We also examined therapeutic potentials of AR expression combined with molecular targeting agent, Sorafenib, in HCC metastasis mouse model.
Results
We found a novel cancer phenotype in which mice lacking hepatic AR developed more undifferentiated tumors and larger tumor size at later metastatic stage. These mice also died earlier with increased lung metastasis, suggesting hepatic-AR may play dual yet opposite roles to promote HCC initiation but suppress HCC metastasis. Mechanistic dissection found that hepatic AR could enhance anoikis and suppress migration of HCC cells via suppression of p38 phosphorylation/activation and the NFκB-MMP9 pathway, respectively. In addition, the in vivo pre-clinical trials concluded that a combination therapy of increased AR expression and reduced multiple-kinase inhibitor (Sorafenib) exhibited better therapeutic efficacy.
Conclusions
Our study demonstrated that AR could orchestrate intrahepatic signalling hierarchies and cellular behavior, consequently affect HCC progression. Results from combination therapy shed a light on developing new therapeutic paradigm for battling HCC at later metastatic stage.
We examined gene expression of hepatocyte growth factor (HGF) and HGF receptor (HGFR), or product of proto-oncogene c-met (c-met), in smokers and nonsmokers with adenocarcinoma (ADC) by suppression subtractive hybridization and microarray techniques. Expression of HGF and c-met was confirmed by RT-PCR. HGF content in the respective tumor mass and nontumor lung tissue was measured by ELISA. HGF in pathologic samples was localized by immunohistochemistry and in situ hybridization. Our results indicate that overexpression of HGFR was frequently detected in ADC cells, whereas overexpression of HGF was detected in alveolar type II (ATII) cells. Overexpression of HGF was correlated with cigarette smoking and tumor stages. In vitro, HGF expression was evaluated in isolated murine ATII cells and in 12 ADC cell lines, and we found that nicotine activated HGF expression in ATII cells and lung cancer cells.
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