Basic Investigation
Pyrvinium Sensitizes Clear Cell Renal Cell Carcinoma Response to Chemotherapy Via Casein Kinase 1α-Dependent Inhibition of Wnt/β-Catenin,☆☆

https://doi.org/10.1016/j.amjms.2017.11.017Get rights and content

Abstract

Background

Aberrant Wnt/β-catenin activation has been shown to play essential roles in cancer, including renal cell carcinoma (RCC). In this work, we demonstrate that Wnt/β-catenin inhibition by a Food and Drug Administration-approved drug, pyrvinium, effectively targets clear cell RCC and enhances chemotherapy agent’s efficacy.

Materials and Methods

We performed in vitro cell culture assays and in vivo xenograft tumor model to evaluate the effects of pyrvinium alone and its combination with paclitaxel, and analyzed the underlying mechanism(s) of pyrvinium’s action in RCC.

Results

We show that pyrvinium inhibits growth and induces apoptosis via caspase pathway in a panel of RCC cell lines. It decreases β-catenin activity and its downstream Wnt-targeted genes transcription via axin-mediated β-catenin protein reduction. Overexpression of β-catenin completely reverses the effects of pyrvinium, demonstrating that β-catenin inhibition is required for pyrvinium’s action in clear cell RCC. Furthermore, we found that pyrvinium failed to decrease β-catenin protein level and activity in casein kinase 1α (CK1α)-depleted clear cell RCC cells, demonstrating that pyrvinium inhibits β-catenin in a CK1α-dependent manner. Notably, decreased tumor growth and β-catenin levels were observed in clear cell RCC xenograft mouse model treated with pyrvinium. Combination of pyrvinium and paclitaxel resulted in greater efficacy in in vitro and in vivo.

Conclusions

Our findings suggest that pyrvinium is a useful addition to the treatment armamentarium for clear cell RCC. Our work also demonstrate that targeting Wnt/β-catenin is a potential therapeutic strategy in clear cell RCC.

Introduction

Renal cell carcinomas (RCC) originate from the renal epithelium and include several subgroups with distinct histologic phenotype and molecular profiling.1, 2 The most frequent subgroups of RCCs are clear cell (~70%), papillary (~20%) and chromophore (~10%). It is resistant to current therapeutic options including chemotherapy, radiotherapy and targeted therapy.3, 4 The carcinogenesis, progression and resistance of RCC involve numerous signaling pathways. Besides PI3K/Akt/mTOR and HGF/Met, Wnt/β-catenin signaling has been identified to actively participate in different biological processes during RCC.5, 6 Our previous work and the work of others emphasizes the importance of Wnt singaling as a potential drug target for the better clinical management of RCC.7

Pyrvinium is a Food and Drug Administration-approved anthelmintic drug for the treatment of animal-like protists. Recent studies have shown its novel anticancer activity as pyrvinium inhibits tumor cell growth in numerous cancer models, such as breast, lung, colon and hematological malignancies.8 Apart from tumor cells, pyrvinium has been reported to be active against tumor stem cells.9, 10 Pyrvinium targets cancer via multiple critical signaling pathways in a cancer cell-type specific manner. The reported molecular mechanisms of pyrvinium’s action in cancer are energy and autophagy depletion,9, 11, 12 activation of casein kinase 1α (CK1α) and inhibition of Wnt/β-catenin or Hedgehog signaling pathways13, 14 and inhibition of JAK/STAT/Akt.15 However, whether pyrvinium is effective in targeting RCC is unknown.

In this study, we systematically investigated the effects of pyrvinium alone and its combination with chemotherapeutic agent paclitaxel in clear cell RCC using a cellular culture system and xenograft mouse tumor model. We also determined the molecular mechanism of pyrvinium’s action in clear cell RCC. We show that pyrvinium induces apoptosis and inhibits RCC cells regardless of cellular origin and genetic profiling. We further show that pyrvinium significantly augments paclitaxel’s efficacy in clear cell RCC in vitro and in vivo. Finally, we demonstrate that pyrvinium targets clear cell RCC cells via inhibiting Wnt/β-catenin signaling in CK1α-dependent manner.

Section snippets

Materials and Methods

The work was approved by institutional review board of Xiangyang Central Hospital. All procedures involving the use of animals were performed according to the guidelines approved by the Institutional Animal Care and Use Committee of Xiangyang Central Hospital.

Pyrvinium is Active Against Renal Carcinoma Cells

To investigate the biological effects of pyrvinium in RCC, we examined the growth and survival rate in a panel of RCC cell lines after pyrvinium treatment. SW-839 and A-498 are cell lines presenting the 2 main subtypes of primary RCC: clear cell and papillary. Caki-1 and ACHN are cell lines presenting the metastatic clear cell and papillary RCC, respectively.16 We found that pyrvinium potently inhibited proliferation in a dose-dependent manner in all RCC cell lines, with IC50 at ~0.5 µM (Figure 1

Discussion

Substantial studies using in vitro and in vivo models have demonstrated the important roles of Wnt/β-catenin in RCC transformation, development and metastases.18, 20, 21 Aberrant activation of Wnt/β-catenin has been found in RCC patients and it is associated with unfavorable clinicopathology and impaired survival.22 In lines with these findings, we and others have also shown that targeting Wnt/β-catenin is effective against multiple biological aspects of RCC, such as growth, colony formation

Conclusions

In conclusion, our results show that pyrvinium is an attractive candidate for clear cell RCC treatment given its efficacy as single drug alone and in combination with chemotherapy agents. Our work also demonstrates that targeting Wnt/β-catenin is a potential therapeutic strategy for clear cell RCC.

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  • Cited by (14)

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    The authors have no conflicts of interest to disclose.

    The first 2 authors (LC, JZ) have contributed equally to this work.

    ☆☆

    This work was supported by research Grants provided by Xiangyang Central Hospital (Grant no. 201366816) and Science and Technology Department of Hubei Province (Grant no. EK2013D16011668122).

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