Phosphorylation of IDH1 Facilitates Progestin Resistance in Endometrial Cancer

Inhibition of lanosterol synthase linking with MAPK/JNK signaling pathway suppresses endometrial cancer

Endometrial cancer (EC) is a significant health threat to women, with recurrence after treatment posing a major challenge. While abnormal cholesterol metabolism has been implicated in EC progression, the underlying mechanisms remain unclear. In this study, we identified lanosterol synthase (LSS) as a key mediator in cholesterol metabolism associated with EC. We found that LSS is significantly upregulated in EC tissues. Functional assays revealed that LSS promotes cell proliferation and migration, inhibits apoptosis, and drives tumor growth in vivo. Mechanistically, LSS exerts dual effects by accumulating cholesterol esters, thereby enhancing EC cell growth, and activating the MAPK/JNK signaling pathway. Importantly, inhibition of LSS with the specific inhibitor Ro 48-8071 not only reduced EC cell proliferation and suppressed xenograft tumor growth but also inhibited the growth of patient-derived tumor-like cell clusters (PTCs). These findings establish LSS as a novel oncogene in EC, promoting tumor progression through MAPK/JNK signaling activation and cholesterol ester accumulation, and highlight the therapeutic potential of targeting LSS in EC treatment.

The Ku70-SIX1-GPT2 axis regulates alpha-ketoglutarate metabolism to drive progression of prostate cancer

Sine oculis homeobox homolog 1 (SIX1) is a new identified cancer driver in the development of prostate cancer (PC). However, the upstream regulatory mechanisms for SIX1 reactivation in cancer remains elusive. Here, we found that Ku70 robustly interacts with SIX1 in the nucleus of PC cells. The HD domain of SIX1 and the DBD domain of Ku70 are required for formation of Ku70-SIX1 complex. 20 groups of hydrogen bonds were identified in this complex by molecular dynamics simulation. Depletion of Ku70/SIX1 notably abrogates the proliferation and migration of PC. Further studies revealed that SIX1 is recruited to the promoter region on glutamate-pyruvate transaminase 2 (GPT2). Ku70 enhances the SIX1-mediated transcriptional activation on GPT2, thereby facilitating the generation of alpha-ketoglutarate (α-KG). In addition, formation of the Ku70-SIX1 complex promotes GPT2-dependent cell proliferation and migration in PC. Moreover, the expression of GPT2 is upregulated and strongly correlated with the expression of Ku70/SIX1 in PC tissues. In summary, our findings not only provide insight into the mechanistic interactions between Ku70 and SIX1, but also highlight the significance of the Ku70-SIX1-GPT2 axis for α-KG metabolism and PC carcinogenesis.