We previously identified TDRG1 (testis developmental related gene 1), a novel gene with exclusive expression in testis, promoted the proliferation and progression of cultured human
seminoma cells through PI3K/Akt/mTOR signaling. As increasing evidence reveal that aberrant activation of this signaling is involved in
cisplatin resistance. Then, in this study, we further explored whether TDRG1 regulated the chemosensitivity of
seminoma TCam-2 cells to
cisplatin. Our researches showed TDRG1 could regulate the viability of TCam-2 cells following
cisplatin treatment in vitro through control of both cell apoptosis and cell cycle. Mechanistically, we observed TDRG1 positively regulated the expression levels of the key elements in PI3K/Akt/mTOR pathway including p-PI3K, p-Akt and p-mTOR and also affected the translocation of nuclear p-Akt in TCam-2 cells during
cisplatin treatment. Meanwhile, the levels of Bad,
cytochrome c,
caspase-9 ratio (activated/total),
caspase-3 ratio (activated/total) and cleaved-PARP were negatively modulated by TDRG1, which meant the involvement of mitochondria-mediated apoptotic pathway. Furthermore, we found the effect of TDRG1 knockdown or TDRG1 overexpression could be reversed by
IGF-1, a PI3K signaling activator, or
LY294002, a inhibitor of this pathway, respectively. Similar effects of TDRG1 on
cisplatin chemosensitivity and associated molecular mechanism were also confirmed in vivo by employing xenograft assays. In addition, the positive correlation between TDRG1 and p-PI3K, or p-Akt, was found in
tumor tissues from
seminoma patients. In conclusion, we uncover that TDRG1 regulates chemosensitivity of TCam-2 cells to
cisplatin through PI3K/Akt/mTOR signaling and mitochondria-mediated apoptotic pathway both in vitro and in vivo.