Proteomics Analysis of Polyphyllin D-Treated Triple-Negative Breast Cancer Cells Reveal the Anticancer Mechanisms of Polyphyllin D.

Polyphyllin D (PD), one of the important steroid saponins in traditional medicinal herb Paris polyphylla, has been demonstrated to have anticancer activity both in vitro and in vivo. However, the mechanisms through which PD exerts its anticancer effects in triple-negative breast cancer (TNBC) remain unclear. Our study was presented to evaluate the anticancer effect and the potential mechanisms of PD in two TNBC cell lines, BT-549 and MDA-MB-231. Through comprehensively comparing the liquid chromatography-tandem mass spectrometry (LC-MS/MS) data of PD-treated and untreated BT-549 and MDA-MB-231 cells, we found that PD could induce apoptosis of TNBC cells by activating oxidative phosphorylation pathway in BT-549 cells, as well as inhibiting spliceosome function alteration in MDA-MB-231 cells. These results suggested that the mechanisms underlying the pro-apoptotic effect of PD on TNBC may be cell type-specificity-dependent. Moreover, we found that nodal modulator 2/3 (NOMO2/3) were downregulated both in PD-treated BT-549 and MDA-MB-231 cells, suggesting that NOMO2/3 may be the potential target of PD. Verification experiments revealed that PD deceased NOMO2/3 expression at protein level, rather than mRNA level. Whether NOMO2/3 are the upstream modulators of oxidative phosphorylation pathway and spliceosome needs further validation. In conclusion, a comprehensive proteomics study was performed on PD-treated or untreated TNBC cells, revealing the anticancer mechanisms of PD.

Polyphyllin D induces apoptosis and protective autophagy in breast cancer cells through JNK1-Bcl-2 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Polyphyllin D (PD), an active component from rhizome of Paris polyphylla Sm, root and rhizome, shows a strong anti-cancer activity in several cancers. However, whether autophagy is involved in PD-induced cell death in breast cancer cells and its molecular mechanism has not yet been elucidated. AIM OF THE STUDY: To explore the anti-tumor effects of PD in breast cancer and the underlying mechanisms. MATERIALS AND METHODS: PD was isolated from P. polyphylla Sm and confirmed by HPLC and NMR. The role of PD in cell viability, apoptosis, autophagy in breast cancer cells were determined. RESULTS: PD shows significant anti-tumor activity by inhibit cell proliferation and induce caspase-dependent apoptosis in breast cancer cells. Moreover, PD treatment could induce autophagy by activation of JNK1/Bcl-2 pathway. Importantly, blocking of autophagy by using autophagy inhibitor 3-methyladenine (3-MA) dramatically increase PD-induced apoptosis as evidence by the increased percentage of apoptotic cell death. The anti-tumor effects of PD also investigated in vivo. The results showed that the combinatory treatment of PD with autophagy inhibitor significantly promote PD-induced apoptosis. CONCLUSION: PD could induce caspase-dependent apoptosis and cyto-protectvie autophagy by activation of JNK1/Bcl-2 pathway in breast cancer cells. Combination with an autophagy inhibitor significantly enhance cytotoxic effect of PD and this combination may be a promising candidate for breast cancer therapy.

[Study on Salt Tolerance of Echinacea purpurea].

OBJECTIVE: To explore the salt tolerance of Echiancea purpurea and its mechanism. METHODS: Echiancea purpurea was used as test material in this study and six salinity levels (0, 30, 60, 90, 120 and 150 mmol/L NaCl) were set. Effects on seed germination and salt tolerance relevant physiological and biochemical indexes of Echiancea purpurea were studied. RESULTS: Salt stress suppressed the germination of Echiancea purpurea seeds, induced osmotic adjustment substances proline, soluble sugar and K+ to increase, and activities of POD and SOD to rise, and meanwhile resulted in accumulation of Na+ and decrease of K+/Na+. CONCLUSION: Echiancea purpurea can tolerant salt stress to a certain degree, but in case of high salt concentrations, severe salt injury would remarkably suppress the growth of Echinacea purpurea.

Auditory pre-attentive processing of Chinese tones.

BACKGROUND: Chinese tones are considered important in Chinese discrimination. However, the relevant reports on auditory central mechanisms concerning Chinese tones are limited. In this study, mismatch negativity (MMN), one of the event related potentials (ERP), was used to investigate pre-attentive processing of Chinese tones, and the differences between the function of oddball MMN and that of control MMN are discussed. METHODS: Ten subjects (six men and four women) with normal hearing participated in the study. A sequence was presented to these subjects through a loudspeaker, the sequence included four blocks, a control block and three oddball blocks. The control block was made up of five components (one pure tone and four Chinese tones) with equiprobability. The oddball blocks were made up of two components, one was a standard stimulus (tone 1) and the other was a deviant stimulus (tone 2 or tone 3 or tone 4). Electroencephalogram (EEG) data were recorded when the sequence was presented and MMNs were obtained from the analysis of the EEG data. RESULTS: Two kinds of MMNs were obtained, oddball MMN and control MMN. Oddball MMN was obtained by subtracting the ERP elicited by standard stimulation (tone 1) from that elicited by deviant stimulation (tone 2 or tone 3 or tone 4) in the oddball block; control MMN was obtained by subtracting the ERP elicited by the tone in control block, which was the same tone as the deviant stimulation in the oddball block, from the ERP elicited by deviant stimulation (tone 2 or tone 3 or tone 4) in the oddball block. There were two negative waves in oddball MMN, one appeared around 150 ms (oddball MMN 1), the other around 300 ms (oddball MMN 2). Only one negative wave appeared around 300 ms in control MMN, which was corresponding to the oddball MMN 2. We performed the statistical analyses in each paradigm for latencies and amplitudes for oddball MMN 2 in discriminating the three Chinese tones and reported no significant differences. But the latencies and amplitudes for control MMN in discriminating the three tones all were significantly different. CONCLUSIONS: There are evident waveforms for oddball and control MMN obtained in normal hearing persons, indicating that the change of Chinese tones could be detected in the pre-attentive stage. Because control MMN can eliminate reflects for physical characteristics of sound, it is the genuine memory-based pre-attentive processing. Since control MMN can reflect the differences of Chinese tones processing better than oddball MMN, it is more sensitive in evaluating pre-attentive processing in Chinese tones discrimination.