Cancer Letters

Cancer Letters

Volume 245, Issues 1–2, 8 January 2007, Pages 242-251
Cancer Letters

Signal therapy of human pancreatic cancer and NF1-deficient breast cancer xenograft in mice by a combination of PP1 and GL-2003, anti-PAK1 drugs (Tyr-kinase inhibitors)

https://doi.org/10.1016/j.canlet.2006.01.018Get rights and content

Abstract

The majority of cancers are caused by mutations of a few signal transducers such as the GTPase RAS, the kinase Src and the tumor suppressor p53. Thus, a group of specific chemical compounds called ‘signal therapeutics’, that block or reverse selectively these abnormally activated signaling pathways would be very useful for the treatment of these signally disordered cancers. More than 90% of human pancreatic cancers are associated with oncogenic mutations of RAS, in particular K-RAS at codon 12. We have previously shown that, PAK1, the Rac/CDC42-dependent Ser/Thr kinase, is essential for RAS/estrogen-induced transformation and neurofibromatosis (NF). Furthermore, we and others have demonstrated that the growth of mouse RAS-induced sarcomas allografts in mice is almost completely suppressed by either FK228 or a combination of two complimentary Tyr-kinase inhibitors, PP1 and AG 879, all of which block the RAS-induced activation of PAK1. Since, so far no effective therapeutic is available for the treatment of pancreatic cancer patients, we have examined the therapeutic potential of either FK228, the combination of these two Tyr-kinase inhibitors or GL-2003, a water-soluble derivative of AG 879, on human pancreatic cancer (Capan-1) xenograft in mice. Among these PAK1-blocking approaches, the PP1/GL-2003 combination is the most effective in the therapy of this cancer xenograft model. Its therapeutic potential is equivalent to those of gemcitabine and kigamicin D which suppress by 70–80% the growth of a similar human pancreatic cancer xenograft model. Also, this PP1/GL-2003 combination therapy has been proven to be very effective to suppress the estrogen-independent growth of an NF1-deficient multidrug/FK228-resistant human breast cancer (MDA-MB-231) xenograft in mice.

Introduction

Every year around 600,000 people on this planet die of pancreatic cancers. The collective median survival time of all pancreatic cancer patients is 4–6 months. The overall 5-year survival rate for this disease is less than 5%. The main reason for such a poor survival rate is that so far no clinically effective therapeutic has been developed for this disease. Around 30% of all human cancers carry oncogenic RAS mutations, and most notably more than 90% of human pancreatic cancers are associated with such mutations, in particular K-RAS at codon 12 [1], which causes the constitutive activation of the G protein RAS, eventually leading to the abnormal activation of PAK1, a Rac/CDC42-dependent Ser/Thr kinase, or another Ser/Thr kinase called AKT/PKB, through the PI-3 kinase cascade [2], [3]. An anti-biotic called kigamicin D, which blocks the PI-3 kinase/AKT pathway, strongly suppresses the growth of human pancreatic cancer xenografts in mice, suggesting that this pathway might be one of the selective targets for anti-pancreatic cancer drugs [3].

FK228, the most potent histone deacetylase (HDAC) inhibitor so far discovered, has been shown to suppress the growth of both v-Ha-RAS-induced sarcoma allograft [4], and human pancreatic cancer cell lines such as Capan-1 in cell culture (IC50: 3 nM) which carry both K-RAS and p53 mutants [5]. Furthermore, we and others found that (i) PAK1 is essential for RAS-transformation [2], [6], that (ii) the growth of RAS-induced sarcoma allograft in mice is almost completely suppressed by a combination of two complementary Tyr-kinase inhibitors, PP1 and AG 879, which block PAK1 activation by inhibiting a Src family kinase(s) and ETK, respectively [2], [7], [8], with their IC50 around 10 nM, and that (iii) FK228 blocks the activation of PAK1 in RAS transformants and estrogen-dependent breast cancer cells [9]. Based on these previous observations, we have examined the therapeutic potential of FK228 alone, a combination of PP1 with either AG 879 or its water-soluble derivative called GL-2003 on the growth of Capan-1 xenograft in mice.

Section snippets

Materials

FK228 was supplied from Astellas Pharma (former Fujisawa Pharmaceuticals) as previously described [10]. PP1 and AG 879 were synthesized as previously [2]. GL-2003, a water-soluble derivative of AG 879, was synthesized via GL-2002 [8], and the detail of their synthesis will be described in Appendix A1 (supplement information). In brief, as shown in Fig. 1, GL-2002 (compound 4) was deprotected with SnCl4 in AcOEt, yielding GL-2003 (compound 5).

The human pancreatic cancer cell line Capan-1 and

PP1 and GL-2003 cause a synergetic effect in the therapy of human pancreatic cancer xenograft in mice

For the combination therapy of PP1 and AG 879, we followed the exact dose (20 mg/kg of each, i.p. twice a week) as we used previously for testing on RAS-induced sarcoma allograft in mice [2]. For FK228 therapy, we chose a mean dose (1.5 mg/kg, i.p. twice a week), between 1 mg/kg for breast cancers xenografts and 2.5 mg/kg for NF xenograft in mice [10], [12]. As shown in Fig. 2, both FK228 alone or the PP1/AG 879 combination showed the almost same anti-cancer potential, that is around 50% inhibition

Acknowledgements

We are grateful to Dr Hidenori Nakajima of Astellas Pharma for his generous gift of FK228 as the positive control, Ms Maureen Nerrie for her soft agar assay, and Prof. Tony Burgess for his continued support. This work was supported in part by the Denise Terrill Classic Award from Texas NF Foundation.

References (21)

  • R. Bagheri-Yarmand et al.

    VEGF up-regulation via PAK1 signaling regulates heregulin-beta1-mediated angiogenesis

    J. Biol. Chem.

    (2000)
  • J. Bos

    Ras oncogenes in human cancer: a review

    Cancer Res.

    (1989)
  • H. He et al.

    Signal therapy for RAS-induced cancers in combination of AG 879 and PP1, specific inhibitors for ErbB2 and Src family kinases, that block PAK activation

    Cancer J.

    (2001)
  • J. Lu et al.

    Kigamicin D, a novel anti-cancer agent based on a new anti-austerity strategy targeting cancer cells' tolerance to nutrient starvation

    Cancer Sci.

    (2004)
  • H. Ueda et al.

    Action of FK228, a novel anti-tumor bicyclic depsipeptide produced by C. violaceum #968, on Ha-RAS transformed NIH3T3 cells

    Biosci. Biotechnol. Biochem.

    (1994)
  • N. Sato et al.

    FK228, a novel HDAC inhibitor, induces cell cycle arrest and subsequent apoptosis in refractory human pancreatic cancer cells

    Int. J. Oncol.

    (2004)
  • Y. Tang et al.

    Kinase-deficient PAK1 mutant inhibits RAS transformation of Rat-1 fibroblasts

    Mol. Cell. Biol.

    (1997)
  • H. He et al.

    An anti-RAS cancer potential of PP1, an inhibitor specific for Src family kinases; in vitro and in vivo studies

    Cancer J.

    (2000)
  • H. He et al.

    The Tyr-kinase inhibitor AG 879, that blocks the ETK–PAK1 interaction, suppresses RAS-induced PAK1 activation and malignant transformation

    Cancer Biol. Ther.

    (2004)
  • Y. Hirokawa et al.

    Signal therapy of breast cancers by the HDAC inhibitor FK228 that blocks the activation of PAK1 and abrogates the tamoxifen-resistance

    Cancer Biol. Ther.

    (2005)
There are more references available in the full text version of this article.

Cited by (37)

  • From bench (laboratory) to bed (hospital/home): How to explore effective natural and synthetic PAK1-blockers/longevity-promoters for cancer therapy

    2017, European Journal of Medicinal Chemistry
    Citation Excerpt :

    Unfortunately, however, FK228 turned out not to pass across the BBB (blood brain barrier), and therefore is useless for therapy of a series of brain tumors and other neuronal diseases/disorders. Furthermore, FK228 tends to induce the drug-resistance in human pancreatic cancers in vivo [8]. Thus, we started searching for an alternative PAK1-blocker(s) useful for the therapy of Gemcitabine (Gem)-resistant pancreatic cancers that represent 90% of human pancreatic cancers.

  • P21-activated kinase 1 (Pak1) signaling influences therapeutic outcome in pancreatic cancer

    2016, Annals of Oncology
    Citation Excerpt :

    It was recently shown that glaucarubinone and gemcitabine synergistically reduce PC growth via down-regulation of Paks [21]. Further, it was reported that therapy with anti-Pak1 drugs—PP1/GL-2003 combination has proven to be most effective in human PC xenograft models [22]. Owing to all this, it is possible that inhibition of Pak1 signaling with more specific small molecule inhibitors could enhance drug sensitivity either alone or with chemotherapy combination and may represent a promising therapeutic strategy for PC.

View all citing articles on Scopus
View full text