A naturally derived small molecule compound suppresses tumor growth and metastasis in mice by relieving p53-dependent repression of CDK2/Rb signaling and the Snail-driven EMT.

The tumor suppressor protein p53 is central to cancer biology, with its pathway reactivation emerging as a promising therapeutic strategy in oncology. This study introduced LZ22, a novel compound that selectively inhibits the growth, migration, and metastasis of tumor cells expressing wild-type p53, demonstrating ineffectiveness in cells devoid of p53 or those expressing mutant p53. LZ22's mechanism of action involves a high-affinity interaction with the histidine-96 pocket of the MDM2 protein. This interaction disrupted the MDM2-p53 binding, consequently stabilizing p53 by shielding it from proteasomal degradation. LZ22 impeded cell cycle progression and diminished cell proliferation by reinstating the p53-dependent suppression of the CDK2/Rb signaling pathway. Moreover, LZ22 alleviated the p53-dependent repression of Snail transcription factor expression and its consequent EMT, effectively reducing tumor cell migration and distal metastasis. Importantly, LZ22 administration in tumor-bearing mice did not manifest notable side effects. The findings position LZ22 as a structurally unique reactivator of p53, offering therapeutic promise for the management of human cancers with wild-type TP53.

Wogonin inhibits multiple myeloma-stimulated angiogenesis via c-Myc/VHL/HIF-1α signaling axis.

Angiogenesis is associated with the progression of multiple myeloma (MM). Wogonin is an active mono-flavonoid with remarkable antitumor activity. However, its impact on MM-stimulated angiogenesis remains largely unknown. Here, we demonstrated that wogonin decreased expression and secretion of pro-angiogenic factors in MM cells via c-Myc/HIF-1α signaling axis, reducing MM-stimulated angiogenesis and MM cell proliferation in vivo. Overexpression of c-Myc in MM cells disrupted the balance between VHL SUMOylation and ubiquitination, and thus inhibited proteasome-mediated HIF-1α degradation. Impaired function of VHL ubiquitination complex in c-Myc-overexpressing cells was fully reversed by wogonin treatment via increasing HIF-1α-VHL interaction and promoting HIF-1α degradation. Collectively, our in vitro and in vivo studies reveal for the first time that wogonin represses MM-stimulated angiogenesis and tumor progression via c-Myc/VHL/HIF-1α signaling axis.

General pharmacological properties, developmental toxicity, and analgesic activity of gambogic acid, a novel natural anticancer agent.

In this article, the general pharmacological toxicity of gambogic acid (GA), a new anticancer agent, on the dog cardiovascular and respiratory system and the mouse central nervous system (CNS) were observed. The developmental toxicity and analgesic activities of GA were also investigated in rats and mice. Results showed that GA did not cause any toxic symptoms on blood pressure (i.e., mean arterial pressure), heart rate (HR), and respiratory frequency. However, a high dose of GA showed slight side effects on the mouse CNS. Further, evidence of maternal and developmental toxicity was observed in a dose-dependent manner. The maternal body-weight gain, as well as the birth weights and live birth index, were decreased significantly in the treatment groups. The inhibitory effects of GA on fetal skeletal development were also found. No obvious effects of GA on external alterations and visceral alterations were shown. In the analgesic experiments, GA showed significant analgesic activity in the acetic-acid-induced writhing study in a dose-dependent manner. This mechanism might be related to its anti-inflammation properties.

General gambogic acids inhibited growth of human hepatoma SMMC-7721 cells in vitro and in nude mice.

AIM: To study the inhibitory effect of general gambogic acids (GGA) on transplantation tumor SMMC-7721 in experimental animal model and SMMC-7721 cells in vitro. METHODS: Anti-tumor activity of GGA in the experimental transplantation tumor SMMC-7721 was evaluated by relative tumor growth ratio. Cell morphology was observed with inverted microscope and electron microscope. Cell proliferation was measured by MTT assay and the telomerase activity was determined by PCR. RESULTS: In vivo study indicated that GGA (2, 4, and 8 mg/kg, iv, 3 times per week for 3 weeks) displayed an inhibitory effect on the growth of transplantation tumor SMMC-7721 in nude mice compared with the normal saline group (P<0.01). At the concentrations of 0.625-5.0 mg/L, GGA remarkably inhibited the proliferation of SMMC-7721 cells in vitro. GGA 2 mg/L dramatically changed morphology of SMMC-7721 cells and inhibited the telomerase activity in SMMC-7721 cells. CONCLUSION: GGA had inhibitory effect on the growth of SMMC-7721, which might be related to its inhibition of telomerase activity.