Combining the farnesyltransferase inhibitor lonafarnib with paclitaxel results in enhanced growth inhibitory effects on human ovarian cancer models in vitro and in vivo
Introduction
Ovarian cancer is the second most common gynecologic malignancy. Epithelial ovarian cancer is the most frequent form of the disease accounting for approximately 90% of all cases. Germ cell and stromal cell ovarian cancer account for the remaining 10% of cases. The majority of ovarian cancer patients are asymptomatic until the disease has metastasized and approximately 70% of patients are diagnosed with advanced disease [1]. After surgical debulking combination chemotherapy with a platinum agent (cisplatin or carboplatin) and paclitaxel is an effective treatment option for ovarian cancer patients [2], [3]. Nonetheless, in the United States 5-year survival is approximately 30% for patients diagnosed with advanced ovarian cancer [4]. This indicates that other forms of treatment are clearly needed and newer treatment paradigms based on our increased knowledge of the molecular mechanisms of cancer growth are presently under investigation.
Lonafarnib is a farnesyltransferase inhibitor (FTI) originally developed to inhibit the farnesylation and, as a consequence, the membrane localization of Ras [5]. This strategy was anticipated to inhibit growth factor receptor-mediated signal transduction pathways. However, in lonafarnib-treated cells 2 of the Ras isoforms (K-Ras and N-Ras) undergo alternative geranylgeranylation and continue to localize to the plasma membrane [6], [7]. Only the membrane localization of H-Ras is inhibited by lonafarnib. Despite the alternative prenylation of K- and N-Ras, lonafarnib is effective at inhibiting the growth of a number of cancer cell lines in culture and tumor xenografts in vivo[8], [9]. The ability of lonafarnib to inhibit tumor growth in preclinical models is most likely due to the inhibition of farnesylation and functional activity of additional proteins. Potential candidate proteins include the mitotic proteins CENP-E and CENP-F, the PRL family of nuclear phosphatases, the small GTPases RhoB and Rheb, and HDJ-2 [reviewed in 5].
In preclinical models additive and/or synergistic interactions have been reported when FTIs including lonafarnib are combined with paclitaxel or docetaxel [10], [11], [12]. This suggests that adding lonafarnib to a paclitaxel-containing chemotherapy regimen may enhance activity and have the potential to provide clinical benefit. In this manuscript we have evaluated the effects of combining lonafarnib with paclitaxel on four paclitaxel-sensitive ovarian cancer cell lines in vitro and in vivo. A2780 and IGROV-1 cells were isolated from patients with serous cell epithelial ovarian cancer. TOV-112D cells are from an endometrioid epithelial carcinoma and PA-1 cells are from an ovarian germ cell teratoma. Previous reports have documented that when lonafarnib is administered as a single-agent therapy Western blotting for mobility shifts in the unfarnesylated form of the chaperone protein HDJ-2 can be used as marker for FTI activity in clinical specimens [13]. Unfarnesylated HDJ-2 has a slower electrophoretic mobility on SDS-PAGE gels when compared to farnesylated HDJ-2 and this allows us to indirectly determine inhibition of farnesyl protein transferase (FTase) enzyme activity. In this report we have further evaluated whether assaying for a HDJ-2 mobility shift can be used as a marker of FTI activity when lonafarnib is administered in combination with paclitaxel. The enhanced anti-tumor activity observed when the xenograft ovarian tumor models were treated with the combination of lonafarnib and paclitaxel correlated better with inhibition of FTase enzyme activity rather than HDJ-2 mobility shifts.
Section snippets
Cell culture
A2780 and IGROV-1 cells from the NCI Tumor Repository (Frederick, MD) were maintained in RPMI-1640 supplemented with 10% fetal bovine serum (FBS). TOV-112D and PA-1 cells were from the American Type Culture Collection (Manassas, VA) and were maintained in DMEM/F12 supplemented with 10% FBS.
Materials
Lonafarnib (SCH66336) is synthesized by Schering-Plough Corporation (Kenilworth, NJ) [14]. Paclitaxel for in vitro studies was from Sigma Chemical Company, (St. Louis, MO) while clinical grade paclitaxel
Effect of lonafarnib in combination with paclitaxel on the growth of ovarian cancer cells in vitro
The concentration of lonafarnib required to inhibit growth of the panel of ovarian cancer cell lines by 50% (IC50) ranged from 0.22 – 7.06 μM (Table 1). A2780 cells were shown to be very sensitive to single-agent lonafarnib while IGROV-1 cells were shown to be relatively resistant. All of the cell lines were extremely sensitive to single-agent paclitaxel with IC50 concentrations ranging from 1.00 – 3.38 nM (Table 1). Both lonafarnib and paclitaxel inhibited growth of the cell lines in a
Discussion
The anti-tumor activity of FTIs such as lonafarnib is known to be independent of the Ras status of the responsive tumors and the mechanism of FTI activity extends beyond inhibiting the farnesylation of Ras [17], [18]. Indeed, of the cell lines used in this report none had mutations in H-Ras or K-Ras. PA-1 cells are N-Ras mutant. Despite the Ras status of the cell lines, in each of these ovarian cancer models lonafarnib clearly enhanced the anti-tumor activity of paclitaxel. In the xenograft
Acknowledgments
We are grateful to the team that administered the agents to the animals twice daily. This was performed by Stacey Taylor, Gongjie Liu, Cindy Marrinan, Michael Malkowski, Bo Yaremko, Lianzhu Liang, Suining Lee, Robert Huryk, Philip Lipari, Xiaoying Wang, and Irma Oliva. The technical assistance of Andrea Basso and Stuart Black is greatly appreciated.
References (29)
- et al.
Thematic review series: lipid posttranslational modifications: farnesyl transferase inhibitors
J Lipid Res
(2006) - et al.
Characterization of Ha-ras, N-ras, Ki-Ras4A, and Ki-Ras4B as in vitro substrates for farnesyl protein transferase and geranylgeranyl protein transferase type I
J Biol Chem
(1997) - et al.
K- and N-Ras are geranylgeranylated in cells treated with farnesyl protein transferase inhibitors
J Biol Chem
(1997) - et al.
The FTI SCH66336 (Lonafarnib) inhibits Rheb farnesylation and mTOR signaling: role in FTI enhancement of taxane and tamoxifen anti-tumor activity
J Biol Chem
(2005) - et al.
The farnesyl transferase inhibitor SCH 66336 induces a G(2)/M or G(1) pause in sensitive human tumor cell lines
Exp Cell Res
(2001) - et al.
Farnesyltransferase inhibitor R115777 (Zarnestra, Tipifarnib) synergizes with paclitaxel to induce apoptosis and mitotic arrest and to inhibit tumor growth of multiple myeloma cells
Blood
(2005) - et al.
Ovarian cancer: epidemiology, biology, and prognostic factors
Semin Surg Oncol
(2000) - et al.
Randomized intergroup trial of cisplatin–paclitaxel versus cisplatin–cyclophosphamide in women with advanced epithelial ovarian cancer; three year results
J Natl Cancer Inst
(2000) - et al.
Phase III trial of carboplatin and paclitaxel compared with cisplatin and paclitaxel in patients with optimally resected stage III ovarian cancer: a Gynecologic Oncology Group Study
J Clin Oncol
(2003) - et al.
Cancer statistics, 2006
CA Cancer J Clin
(2006)
Antitumor activity of SCH 66336, an orally bioavailable tricyclic inhibitor of farnesyl protein transferase, in human tumor xenograft models and wap-ras transgenic mice
Cancer Res
Combination therapy with the farnesyl protein transferase inhibitor SCH66336 and SCH58500 (p53 adenovirus) in preclinical cancer models
Cancer Res
Farnesyl transferase inhibitors cause enhanced mitotic sensitivity to taxol and epothilones
Proc Natl Acad Sci USA
The farnesyl protein transferase inhibitor SCH66336 synergizes with taxanes in vitro and enhances their antitumor activity in vivo
Cancer Chemother Pharmacol
Cited by (17)
Paclitaxel and cancer treatment: Non-mitotic mechanisms of paclitaxel action in cancer therapy
2021, Paclitaxel: Sources, Chemistry, Anticancer Actions, and Current BiotechnologyTriggered release of paclitaxel from magnetic solid lipid nanoparticles by magnetic hyperthermia
2018, Materials Science and Engineering CCitation Excerpt :Preparing magnetic SNLs based on long chain fatty acids exhibiting a melting point a few degrees above body temperature, is a promising strategy to control drug delivery in specific sites via magnetic hyperthermia [11, 21, 22]. One of the most widely used anticancer drugs, paclitaxel (PTX), a drug extracted from the bark of Taxus brevifolia, has gained attention for its efficacy against several types of cancers such as ovarian [23], breast [24, 25], lung [26], and prostate [27], among others [28]. However, PTX presents low aqueous solubility and, due to its low selective and non-specificity body distribution, it is toxic to normal cells.
Integrated microRNA and mRNA signatures in peripheral blood lymphocytes of familial epithelial ovarian cancer
2018, Biochemical and Biophysical Research CommunicationsCitation Excerpt :DNAJA1 is a target gene of miR-335. Evidence shows that HDJ2, also known as DNAJA1, enhances the growth inhibitory effects in human ovarian cancer induced by farnesyltransferase inhibitor lonafarnib and paclitaxel [52]. The other pivotal miRNA, hsa-miR-136 (miR-136), is reported to target Smad2 and Smad3, promoters of epithelial-mesenchymal transition induced by TGF-b/Smad signaling, and suppresses metastasis-associated traits of lung adenocarcinoma cells [53].
Farnesyltransferase inhibitors: CAAX mimetics based on different biaryl scaffolds
2014, Bioorganic and Medicinal Chemistry LettersRandomized phase II trial of carboplatin and paclitaxel with or without lonafarnib in first-line treatment of epithelial ovarian cancer stage IIB-IV
2012, Gynecologic OncologyCitation Excerpt :The addition of targeted drugs to standard chemotherapy could be another option. Epidermal growth factor inhibitors, antiangiogenetic drugs, or farnesyltransferase inhibitors might be among the candidates for such an approach [20,27]. Lonafarnib is a farnesyltransferase inhibitor that is active against a broad spectrum of tumor cell lines in vitro and tumor xenografts in nude mice [20,21,27].
Thiazole- and imidazole-containing peptidomimetic inhibitors of protein farnesyltransferase
2011, Bioorganic and Medicinal Chemistry Letters