Lactamase β reprograms lipid metabolism to inhibit the progression of endometrial cancer through attenuating MDM2-mediated p53 ubiquitination and degradation.

Background: Lactamase β (LACTB) inhibits the metastasis and progression of multiple malignant tumors. However, little is known about its role in endometrial cancer (EC). Our study aimed to investigate the function and potential molecular mechanism of LACTB in modulating EC progression.

Methods: LACTB expression was measured via immunohistochemistry staining, western blot and qRT-PCR. The role of LACTB in EC was investigated both in vivo and in vitro by employing xenograft mice models and using colony formation, EdU, and Transwell assays, along with flow cytometric analysis. In addition, to assess LACTB function on lipid metabolism, lipid droplets in EC cells were labeled with Nile red. Western blot, immunofluorescence staining, co-immunoprecipitation, ubiquitination assay, and cycloheximide chase assay and rescue experiments were performed to confirm the interaction between LACTB, p53, and MDM2 in EC.

Results: LACTB expression was downregulated in EC. LACTB inhibited the malignant phenotypes and reprogramed lipid metabolism in EC cells. Moreover, LACTB significantly upregulated p53 by attenuating the MDM2-mediated ubiquitination and degradation of p53. Besides, LACTB silencing facilitated the malignant phenotypes and reprogramed lipid metabolism in EC cells; this was reversed with p53 overexpression. LACTB knockdown facilitated EC progression via downregulating p53 in vivo.

Conclusion: LACTB repressed EC cell proliferation and metastasis, and reprogramed lipid metabolism via attenuating the MDM2-mediated ubiquitination and degradation of p53.