Background: Mesenchymal stem cells (MSCs) are pluripotent mesenchymal cells present in various adult tissues. MSCs secrete exosomes as regulators of the tumor niche, with involvement in tumorigenesis and metastasis. The regulatory role of microRNAs (miRs or miRNAs) in MSCs via targeting cyclin E1 (CCNE1) or cyclin E2 (CCNE2) has been extensively reported. Since exosomes are considered as protective and enriched sources of shuttle miRNAs, we hypothesized that exosomal transfer of miR-144 from bone marrow-derived MSCs (BMMSCs) would affect the development of non-small cell lung cancer (NSCLC) cells by targeting CCNE1 and CCNE2. Methods: We first quantified the levels of miR-144, CCNE1, and CCNE2 in NSCLC tissues and cell lines and then undertook gain- and loss-of-function studies of miR-144, CCNE1, and CCNE2 to investigate their roles in the biological characteristics of NSCLC in vitro. NSCLC cells (A549) were exposed to exosomes derived from MSCs, and cell proliferation and colony formation rate were determined using in vitro assays. Finally, effects of BMMSC-derived exosomal miR-144 on tumor development were studied in vivo. Results: In NSCLC tissues and cell lines, miR-144 was expressed poorly and CCNE1 and CCNE2 were expressed highly. Artificially elevating miR-144 inhibited cell proliferation, colony formation, and the number of S phase-arrested cells in NSCLC by downregulating CCNE1 and CCNE2. Additionally, BMMSC-derived exosomal miR-144 led to restrained NSCLC cell proliferation and colony formation. These inhibitory effects of BMMSC-derived exosomes carrying miR-144 on NSCLC were confirmed by experiments in vivo. Conclusion: Collectively, these findings revealed inhibitory effects of BMMSC-derived exosomal miR-144 on NSCLC progression, which were mediated by downregulation of CCNE1 and CCNE2.

Microtubule associated series/threonine kinase-3 (MAST3) is a member of microtubule associated serine/threonine kinase family (MAST1-4, MAST-like), and the expression and underlying molecular mechanism of MAST3 in human tumors, including breast cancer, is not yet elucidated. We employed immunohistochemistry to assess the significant expression of MAST3 in breast cancer tissue samples. Additionally, we utilized an overexpression vector and shRNA to bi-directionally regulate MAST3 expression, aiming to observe the impact of MAST3 on the proliferation, migration, and invasion capabilities of breast cancer cells. Furthermore, we employed immunoprecipitation, immunoblotting, luciferase reporter genes and real-time quantitative PCR to investigate the interaction between MAST3 and YAP, as well as the regulatory effects on the expression of Hippo pathway-related target genes. Low MAST3 expression was observed both in breast cancer cells and tissues, which was significantly associated with advanced tumor T stage, lymph node metastasis, and poor patient prognosis. Functional experiments found that overexpression of MAST3 can gradually inhibit the proliferation and invasion of breast cancer cells, knocking-out MAST3 showed the opposite functional effect. Immunoprecipitation showed that MAST3 interacts with the key effector factor, yes-associated protein (YAP), in the Hippo pathway. The combination of MAST3-YAP promoted the phosphorylation of YAP, which led to its degradation through the ubiquitin-proteasome pathway and reduced nuclear translocation. MAST3 was identified as a novel tumor suppressor protein in breast cancer, which directly regulates the expression of YAP through the non-dependent mammalian sterile-20-like (MST)-large tumor suppressor (LATS) classical signaling pathway, providing a theoretical and experimental basis for the development of small-molecule tumor inhibitors in breast cancer.

Non-small cell lung cancer (NSCLC) remains a formidable challenge in oncology, underscoring the urgent need for innovative therapeutic strategies. This study explores the potential of PD-1-modified multifunctional nanovesicles (NVs) loaded with 5-azacytidine (5-Aza) for NSCLC treatment. By integrating bioinformatics analyses with in vitro and in vivo experiments, methylation-driven genes closely associated with NSCLC progression and prognosis—CLEC3B, CYP27A1, CYP4B1, and NR0B2—were identified. Functional assays revealed that 5-Aza effectively demethylates these genes, reducing NSCLC cell proliferation, migration, and invasion. PD-1-modified NVs demonstrated precise targeting of NSCLC cells via PD-L1 binding, while the combination of PD-1 NVs and 5-Aza synergistically enhanced peripheral blood mononuclear cell activation, induced apoptosis, and amplified anti-tumor immunity. In vivo, studies confirmed the tumor-targeting ability and significant therapeutic efficacy of PD-1 NVs. This synergistic strategy of epigenetic modulation and immune activation offers a promising avenue for NSCLC management. These findings contribute valuable insights into developing targeted nanotherapeutics for effective NSCLC treatment.