Pancreatic cancer (PC) is one of the most malignant types of cancer, and is characterized by early metastasis, limited response to chemotherapeutics, and poor prognosis. Therefore, there is an urgent need to explore new therapeutic strategies for PC treatment. Human rhomboid-like 2 (RHBDL2) is differentially expressed in cervical and breast cancer. However, the correlation between RHBDL2 and PC remains unclear. We found that RHBDL2 is highly expressed in human PC cells and tissues and is significantly associated with distant metastasis and poor survival of patients with PC. Gain- and loss-of-function assays indicated that RHBDL2 could accelerate PC cell proliferation and mobility in vitro and in vivo. The RNA-Seq results suggest that RHBDL2 may be involved in the activation of Notch signaling pathway. IMR-1 could restore the proliferation and metastatic capacity of PC cells mediated by RHBDL2. RHBDL2 interacted with and cleaved Notch1, resulting in the release of N1ICD. RHBDL2 decreased the ubiquitination level of N1ICD and collaborated with Ovarian tumor domain-containing 7B (OTUD7B) to stabilize N1ICD via the ubiquitin-proteasome pathway. RHBDL2 facilitated PC cell proliferation and mobility by stabilizing the N1ICD via the OTUD7B and activating the Notch signaling pathway. Thus, targeting this novel pathway may be a potential therapeutic strategy for PC.
Hepatocellular carcinoma (HCC) expresses abundant glycolytic enzymes and displays comprehensive glucose metabolism reprogramming. Aldolase A (ALDOA) plays a prominent role in glycolysis; however, little is known about its role in HCC development. In the present study, we aim to explore how ALDOA is involved in HCC proliferation. HCC proliferation was markedly suppressed both in vitro and in vivo following ALDOA knockout, which is consistent with ALDOA overexpression encouraging HCC proliferation. Mechanistically, ALDOA knockout partially limits the glycolytic flux in HCC cells. Meanwhile, ALDOA translocated to nuclei and directly interacted with c-Jun to facilitate its Thr93 phosphorylation by P21-activated protein kinase; ALDOA knockout markedly diminished c-Jun Thr93 phosphorylation and then dampened c-Jun transcription function. A crucial site Y364 mutation in ALDOA disrupted its interaction with c-Jun, and Y364S ALDOA expression failed to rescue cell proliferation in ALDOA deletion cells. In HCC patients, the expression level of ALDOA was correlated with the phosphorylation level of c-Jun (Thr93) and poor prognosis. Remarkably, hepatic ALDOA was significantly upregulated in the promotion and progression stages of diethylnitrosamine-induced HCC models, and the knockdown of ALDOA strikingly decreased HCC development in vivo . Our study demonstrated that ALDOA is a vital driver for HCC development by activating c-Jun-mediated oncogene transcription, opening additional avenues for anti-cancer therapies.
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