During both treatment phases, mice were examined daily to assess activity level, ascites development and ability to access food and water

During both treatment phases, mice were examined daily to assess activity level, ascites development and ability to access food and water. monotherapy. These studies indicate that CHFR varies among ovarian cancers but is unlikely to be an independent biomarker for poor response to taxanes. Abstract The poly(ADP-ribose) binding protein CHFR regulates cellular responses to mitotic stress. The deubiquitinase UBC13, which regulates CHFR levels, has been associated with better overall survival in paclitaxel-treated ovarian cancer. Despite the extensive use of taxanes in the treatment of ovarian cancer, little is known about expression of CHFR itself in this disease. In the present study, tissue microarrays containing ovarian carcinoma samples from 417 women who underwent initial surgical debulking were stained with anti-CHFR antibody and scored in a blinded fashion. CHFR levels, expressed as a modified H-score, were examined for association with histology, grade, time to progression (TTP) and overall survival (OS). In addition, patient-derived xenografts from 69 ovarian carcinoma patients were examined for Itga10 CHFR expression and sensitivity to paclitaxel monotherapy. In clinical ovarian cancer specimens, CHFR expression was positively associated with serous histology (= 0.0048), higher grade (= 0.000014) and higher stage (= 0.016). After correction for stage and debulking, there was no significant association between CHFR staining and overall survival (= 0.62) or time to progression (= 0.91) in patients with high grade serous cancers treated with platinum/taxane chemotherapy (N = 249). Likewise, Bindarit no association between CHFR expression and paclitaxel sensitivity was observed in ovarian cancer PDXs treated with paclitaxel monotherapy. Accordingly, differences in CHFR expression are unlikely to play a major role in paclitaxel sensitivity of high grade serous ovarian cancer. gene is frequently inactivated in cancer cells [1,2,3,4,5]. CpG island methylation within the promoter is associated with a poor prognosis in multiple cancer types [5], including microsatellite stable colorectal cancer [22,23]. On the other hand, promoter methylation is also associated with increased taxane sensitivity in colorectal cancer [24], gastric cancer [25], and nonsmall cell lung cancer [26]. Likewise, silencing of is associated with increased taxane sensitivity in endometrial [27,28] and cervical cancer cell lines [29]. Ovarian carcinomas are the most lethal of all gynecologic malignancies [30]. Current first line treatment includes debulking surgery and adjuvant or neoadjuvant therapy with a combination of a platinum and a taxane, usually paclitaxel [31]. Taxanes are also used in the recurrent setting for both platinum sensitive and resistant ovarian cancers [32]. Despite this widespread use of taxanes, little is known about CHFR in ovarian cancer. One early study indicated that the gene is neither methylated nor mutated in ovarian cancer [33], whereas a subsequent report indicated that the gene is hypermethylated and downregulated at the mRNA level [34]. More recently, the deubiquitinase UBC13, acting through its substrate DNMT1, was shown to cause increased methylation of the locus and diminished CHFR expression [35]. Importantly, UBC13 was also shown to be lower in ovarian cancer samples that had a shorter disease-free survival after paclitaxel-containing therapy, leading to the conclusion that low UBC13 and high CHFR might be mediators of paclitaxel resistance in ovarian cancer [35]. Because of the substantial toxicities of paclitaxel, including peripheral neuropathy and leukopenia [36], the ability to identify patients most likely to respond would be beneficial clinically. None of these studies directly examined the CHFR protein or assessed the relationship between CHFR expression and treatment outcome. In the present study, we describe the generation and credentialing of an anti-CHFR antibody specifically generated for immunohistochemistry (IHC), then use this antibody to examine the relationship between CHFR expression and treatment outcome in newly diagnosed epithelial ovarian cancers treated with adjuvant platinum/taxane Bindarit therapy and in ovarian cancer patient-derived xenografts (PDXs) treated with paclitaxel monotherapy. 2. Results 2.1. Development of an Antibody for Studying CHFR Expression Based on previous studies showing an association between CHFR protein levels and taxane resistance in various cancers both in vitro [16,21,27,37] and in the clinical setting [26], we examined the relationship between CHFR expression and clinical outcome in patients with epithelial ovarian cancer. Although the latter study used a commercial anti-CHFR antibody, that reagent was not credentialed for immunohistochemistry (IHC) by Bindarit the supplier and is no longer available. Accordingly, to provide a suitable reagent for.