Native V. Californicum Alkaloid Combinations Induce Differential Inhibition of Sonic Hedgehog Signaling

Veratrum californicum is a rich source of steroidal alkaloids such as cyclopamine, a known inhibitor of the Hedgehog (Hh) signaling pathway. Here we provide a detailed analysis of the alkaloid composition of V. californicum by plant part through quantitative analysis of cyclopamine, veratramine, muldamine and isorubijervine in the leaf, stem and root/rhizome of the plant. To determine if additional alkaloids in the extracts contribute to Hh signaling inhibition, we replicated the concentrations of these alkaloids observed in extracts using commercially available standards and compared the inhibitory potential of the extracts to alkaloid standard mixtures using Shh-Light II cells. Alkaloid combinations enhanced Hh signaling pathway antagonism compared to cyclopamine alone, and significant differences were observed in the Hh pathway inhibition between the stem and root/rhizome extracts and their corresponding alkaloid standard mixtures, indicating that additional alkaloids present in these extracts contribute to Hh signaling inhibition.

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Native V. californicum Alkaloid Combinations Induce Differential Inhibition of Sonic Hedgehog Signaling

Molecules ◽

10.3390/molecules23092222 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2222 ◽

Cited By ~ 1

Author(s):

Matthew Turner ◽

Roberto Cruz ◽

Jordan Elwell ◽

John French ◽

Jared Mattos ◽

...

Keyword(s):

Quantitative Analysis ◽

Signaling Pathway ◽

Sonic Hedgehog ◽

Hedgehog Signaling ◽

Plant Part ◽

Differential Inhibition ◽

Sonic Hedgehog Signaling ◽

Alkaloid Composition ◽

Hh Signaling ◽

Pathway Inhibition

Veratrum californicum is a rich source of steroidal alkaloids such as cyclopamine, a known inhibitor of the Hedgehog (Hh) signaling pathway. Here we provide a detailed analysis of the alkaloid composition of V. californicum by plant part through quantitative analysis of cyclopamine, veratramine, muldamine and isorubijervine in the leaf, stem and root/rhizome of the plant. To determine whether additional alkaloids in the extracts contribute to Hh signaling inhibition, the concentrations of these four alkaloids present in extracts were replicated using commercially available standards, followed by comparison of extracts to alkaloid standard mixtures for inhibition of Hh signaling using Shh-Light II cells. Alkaloid combinations enhanced Hh signaling pathway antagonism compared to cyclopamine alone, and significant differences were observed in the Hh pathway inhibition between the stem and root/rhizome extracts and their corresponding alkaloid standard mixtures, indicating that additional alkaloids present in these extracts are capable of inhibiting Hh signaling.

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p63 sustains self-renewal of mammary cancer stem cells through regulation of Sonic Hedgehog signaling

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1500762112 ◽

2015 ◽

Vol 112 (11) ◽

pp. 3499-3504 ◽

Cited By ~ 95

Author(s):

Elisa Maria Memmi ◽

Anna Giulia Sanarico ◽

Arianna Giacobbe ◽

Angelo Peschiaroli ◽

Valentina Frezza ◽

...

Keyword(s):

Stem Cell ◽

Signaling Pathway ◽

Sonic Hedgehog ◽

Hedgehog Signaling ◽

Breast Tumorigenesis ◽

Sonic Hedgehog Signaling ◽

Self Renewal ◽

Genes Encoding ◽

Hh Signaling

The predominant p63 isoform, ΔNp63, is a master regulator of normal epithelial stem cell (SC) maintenance. However, in vivo evidence of the regulation of cancer stem cell (CSC) properties by p63 is still limited. Here, we exploit the transgenic MMTV-ErbB2 (v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2) mouse model of carcinogenesis to dissect the role of p63 in the regulation of mammary CSC self-renewal and breast tumorigenesis. ErbB2 tumor cells enriched for SC-like properties display increased levels of ΔNp63 expression compared with normal mammary progenitors. Down-regulation of p63 in ErbB2 mammospheres markedly restricts self-renewal and expansion of CSCs, and this action is fully independent of p53. Furthermore, transplantation of ErbB2 progenitors expressing shRNAs against p63 into the mammary fat pads of syngeneic mice delays tumor growth in vivo. p63 knockdown in ErbB2 progenitors diminishes the expression of genes encoding components of the Sonic Hedgehog (Hh) signaling pathway, a driver of mammary SC self-renewal. Remarkably, p63 regulates the expression of Sonic Hedgehog (Shh), GLI family zinc finger 2 (Gli2), and Patched1 (Ptch1) genes by directly binding to their gene regulatory regions, and eventually contributes to pathway activation. Collectively, these studies highlight the importance of p63 in maintaining the self-renewal potential of mammary CSCs via a positive modulation of the Hh signaling pathway.

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