Corrigendum to "Reengineered tricyclic anti-cancer agents" [Bioorg. Med. Chem. 23 (2015) 6528-6534]

Q-marker identification of Paris polyphylla var. yunnanensis (Franch.) Hand.-Mazz. in pulmonary metastasis of liver cancer mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizoma Paridis saponins (RPS) as the mainly active components of Paris polyphylla var. yunnanensis (Franch.) Hand.-Mazz., possess tumor therapeutic potential. However, the anti-tumor material basis of RPS in liver cancer pulmonary metastasis remains poorly understood. The objective of this study was to identify the distribution and anti-cancer effects of RPS in liver cancer pulmonary metastatic model.

MATERIALS AND METHODS

In this study, a mouse liver cancer pulmonary metastasis model was established to determine the distribution of different saponins in the tissues by UPLC-MS and plasma protein binding rate.

RESULTS

As a result, RPS prolonged the survival time and inhibited the pulmonary metastasis in H22 injected mice through its underlying mechanism. UPLC-MS identified saponins from RPS such as PVII, PH, PVI, PII, gracillin and PI in tissues, which may be regarded as the Q-markers in RPS. Surprisingly, the concentration of PI, PII and gracillin as diosgenyl saponins was higher than that of pennogenyl saponins in the liver and lung. Besides, plasma protein binding rate of PII was higher than that of PVII.

CONCLUSION

These findings suggested that PVII, PH, PVI, PI, PII and gracillin are regarded as the Q-markers of RPS in liver cancer pulmonary metastasis. The concentration of PI, PII and gracillin as diosgenyl saponins was higher than that of pennogenyl saponins in the liver and lung. It would be helpful for understanding the importance of RPS with anticancer activities in the future.

Direct activation of PP2A for the treatment of tyrosine kinase inhibitor-resistant lung adenocarcinoma

Although tyrosine kinase inhibitors (TKIs) have demonstrated significant efficacy in advanced lung adenocarcinoma (LUAD) patients with pathogenic alterations in EGFR, most patients develop acquired resistance to these agents via mechanisms enabling the sustained activation of the PI3K and MAPK oncogenic pathways downstream of EGFR. The tumor suppressor protein phosphatase 2A (PP2A) acts as a negative regulator of these pathways. We hypothesize that activation of PP2A simultaneously inhibits the PI3K and MAPK pathways and represents a promising therapeutic strategy for the treatment of TKI-resistant LUAD. After establishing the efficacy of small molecule activators of PP2A (SMAPs) in a transgenic EGFRL858R model and TKI-sensitive cell lines, we evaluated their therapeutic potential in vitro and in vivo in TKI-resistant models. PP2A activation resulted in apoptosis, significant tumor growth inhibition, and downregulation of PI3K and MAPK pathways. Combination of SMAPs and TKI afatinib resulted in an enhanced effect on the downregulation of the PI3K pathway via degradation of the PP2A endogenous inhibitor CIP2A. An improved effect on tumor growth inhibition was observed in a TKI-resistant xenograft mouse model treated with a combination of both agents. These collective data support the development of PP2A activators for the treatment of TKI-resistant LUAD.