Weroha, S. John

Objective: A growing number of cancer antineoplastic agents can cause life-threatening acute infusion reactions. Because previous studies have not studied these reactions from the perspective of patients, this study was undertaken with that objective in mind. Methods: Patients who had an acute infusion reaction were interviewed based on the Leventhal model. Once saturation of content was achieved, interviews were transcribed and analyzed with qualitative methodology. Results: Twenty-one patients were enrolled. Most were women (n = 15); the median age was 58 years, and paclitaxel was the most common inciting agent. Three themes emerged. First, these reactions are frightening; patients made remarks such as “I was just thinking oh my God, I am dying.” Second, prior education about these reactions seemed to mitigate this fear, “Basically everything the nurses told me potentially could happen, like happened. So, I was prepared.” Third, when health-care providers were prompt and attentive during the reaction, patients described less fear with future chemotherapy, “So no, I’m really not fearful about going in tomorrow because I know they’ll be there and they’ll be watching me.” Conclusion: These reactions evoke fear which can be mitigated with education prior to and with prompt responsiveness during the acute infusion reaction.

Abstract Patient-derived tumor xenograft (PDX) mouse models have emerged as an important oncology research platform to study tumor evolution, mechanisms of drug response and resistance, and tailoring chemotherapeutic approaches for individual patients. The lack of robust standards for reporting on PDX models has hampered the ability of researchers to find relevant PDX models and associated data. Here we present the PDX models minimal information standard (PDX-MI) for reporting on the generation, quality assurance, and use of PDX models. PDX-MI defines the minimal information for describing the clinical attributes of a patient's tumor, the processes of implantation and passaging of tumors in a host mouse strain, quality assurance methods, and the use of PDX models in cancer research. Adherence to PDX-MI standards will facilitate accurate search results for oncology models and their associated data across distributed repository databases and promote reproducibility in research studies using these models. Cancer Res; 77(21); e62–66. ©2017 AACR.

Abstract E26 transformation-specific transcription factor ERG is aberrantly overexpressed in approximately 50% of all human prostate cancer due to TMPRSS2-ERG gene rearrangements. However, mice with prostate-specific transgenic expression of prostate cancer–associated ERG alone fail to develop prostate cancer, highlighting that ERG requires other lesions to drive prostate tumorigenesis. Forkhead box (FOXO) transcription factor FOXO1 is a tumor suppressor that is frequently inactivated in human prostate cancer. Here, we demonstrate that FOXO1, but not other FOXO proteins (FOXO3 and FOXO4), binds and inhibits the transcriptional activity of prostate cancer–associated ERG independently of FOXO1 transcriptional activity. Knockdown of endogenous FOXO1 increased invasion of TMPRSS2–ERG fusion–positive VCaP cells, an effect completely abolished by ERG knockdown. Patient specimen analysis demonstrated that FOXO1 and ERG protein expression inversely correlated in a subset of human prostate cancer. Although human ERG transgene expression or homozygous deletion of Foxo1 alone in the mouse prostate failed to promote tumorigenesis, concomitant ERG transgene expression and Foxo1 deletion resulted in upregulation of ERG target genes, increased cell proliferation, and formation of high-grade prostatic intraepithelial neoplasia. Overall, we provide biochemical and genetic evidence that aberrantly activated ERG cooperates with FOXO1 deficiency to promote prostate tumorigenesis and cell invasion. Our findings enhance understanding of prostate cancer etiology and suggest that the FOXO1–ERG signaling axis can be a potential target for treatment of prostate cancer. Cancer Res; 77(23); 6524–37. ©2017 AACR.

Abstract Ovarian cancer is the most lethal gynecologic cancer and the fifth most common cause of cancer death among women in the United States. Although there have been incremental improvements in progression free survival over the last several decades from advances in surgical technique and combination-chemotherapy strategies, overall survival has essentially remained unchanged. Although novel therapeutics have the potential to impact overall survival and lead to more cures, drug development in this area has been limited by the availability of clinically relevant models that recapitulate the molecular and phenotypic characteristics of primary ovarian cancers. To overcome this barrier, we have developed primary patient derived xenograft (PDX) models from every consenting patient having primary debulking surgery at Mayo Clinic since 2010 (>550 unique patients). Fresh tissues are minced and injected intraperitoneally into severe combined immunodeficient (SCID) mice without enzymatic digestion or surgical implantation. The patient-to-mouse time is typically <1.5 hours and the engraftment rate is 73%. Ovarian PDX models have demonstrated their utility as patient surrogates. The histologic diversity is representative of the population from which they are derived with high-grade serous comprising most of the models. However, the ovarian PDX bank also includes less-common subtypes, such as clear cell, mucinous, and carcinosarcoma. Histologic and genomic fidelity is maintained within early-passage tumors. Moreover, the patient's clinical response to carboplatin and paclitaxel (a standard front-line therapy for ovarian cancer) demonstrates high correlation to the matched PDX tumor response in vivo, supporting their relevance as patient surrogates. The models have been used for preclinical drug development and biomarker validation. One example is the correlation between PARPi response in PDXs and their homologous recombination deficiency (HRD) score. All models with a low HRD score, <42, failed to respond to PARP inhibition while models with a high HRD score showed enrichment for response to a PARPi. Ovarian PDXs are also being used to direct patient care in a clinical trial setting at all three Mayo Clinic sites (MN, FL, and AZ). Tumors are collected at the time of debulking surgery for heterotransplantation. Subsequent xenografts are treated with standard first-line chemotherapy, similar to their matched patient in the clinic, and then PDXs are treated with standard ovarian cancer second-line therapies: liposomal doxorubicin, topotecan, gemcitabine, and paclitaxel. When patients develop platinum-resistant recurrent cancer, the chemotherapy response in the PDX is used to direct therapy in the clinic. Many challenges continue for ovarian cancer PDX models. The use of immunocompromised mice limits the ability to study the involvement of immunity in chemotherapy responsiveness. In addition, these models are not ideal for testing novel immunotherapies, such as the immune check point inhibitors. Further work to overcome these and other limitations are needed. Citation Format: S. John Weroha. Ovatars in preclinical drug development and clinical trial for ovarian cancer patients. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA11.

Abstract Resistance is one the main reason for overall decrease in survival of cancer patient treated with cisplatin in different types of cancer. Cisplatin kills cancer cells by various mechanisms, but mainly through formation of inter- and intra stand crosslinks of DNA. Different types of translesion polymerase including Polymerase kappa (POLK) are involved in repair of DNA lesions. We observed high expression levels of POLK in cisplatin resistant bladder and ovarian cancer cells compared to parental cells. Due to its low proof-reading activity POLK can incorporate 8-oxo-dGTP into DNA. The MTH1 protein (Nudix hydrolase- NUDT1) sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Recently we have generated MTH1 inhibitors that damage the DNA and induce cancer specific cell death through incorporation of more oxidized dNTPs. We found cisplatin resistant bladder cancer cells (NTUB1/P) were more sensitive to MTH1 inhibitors in comparison to parental NTUB1 cells. As POLK is involved in incorporation of 8-oxo-dGTP into DNA, we hypothesized that high expression levels of POLK in cisplatin resistant cells make them more sensitive to MTH1 inhibitors as more 8-oxo-dGTP would be incorporated into DNA, resulting in more DNA damage and cell death in comparison to parental cells. Indeed, we observes higher induction of cleaved-PARP, γH2AX, cleaved-Caspase 3 and more annexin v positive cells in cisplatin resistant NTUB1/P cells in comparison to parental NTUB1 cells upon treatment with MTH1 inhibitors. MTH1 inhibitor also significantly delays the NTUB1/P xenograft tumor growth in comparison to vehicle treatment in immunosuppressive mice. Knocking down POLK in cisplatin resistant NTUB1/P cells by siRNA resulted in decreased incorporation of 8-oxo-dGTP and sensitivity to MTH1 inhibitors compared to non target control cells. Overexpression of POLK in NTUB1 and NTUB1/P cells results in further sensitization to MTH1 inhibitors. In conclusion elevated levels of POLK in cisplatin resistance cells determines increased sensitivity towards MTH1 inhibitors. Thus MTH1 inhibitors can be a potential promising therapy for the treatment of cisplatin resistant tumors in patients. Citation Format: Kumar Sanjiv, Helge Gad, Sean Rudd, Rachel Hurley, Patric Herr, José Manuel Calderón Montaño, Oliver Mortusewicz, Tobias Koolmeister, Sylvain Jaques, Estefanía Burgos Morón, Andreas Hoglund, Te-Chang Lee, Martin Scobie, Scott Kaufmann, John Weroha, Ulrika Warpman Berglund, Andrea Wahner Hendrickson, Thomas Helleday. Polymerase kappa determines the sensitivity of MTH1 inhibitors to cisplatin-resistant cell. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1260.

Abstract Purpose: Treatment of recurrent ovarian cancer is limited by low response rates to salvage chemotherapy. Novel small molecule inhibitors to Chk1 (checkpoint kinase 1) have been proposed to potentiate the cytotoxic effect of one such salvage treatment, gemcitabine, by interrupting the DNA damage repair pathway. Patient derived tumorgrafts were characterized by responsiveness to gemcitabine +/- MK8776 (Chk1 inhibitor). Response was correlated with markers of Chk1 activity. Methods: Patient-derived tumorgraft models were created from patients undergoing surgery for epithelial ovarian cancer. Gemcitabine response was characterized in five high-grade serous models (PH044, PH048, PH070, PH080, and PH110). Two models (PH048 and PH080) were treated with gemcitabine monotherapy (240 mg/kg qweek x 4 doses), MK8776 monotherapy (32 mg/kg qweek x 4 doses), and with combination therapy (Gemcitabine 190 mg/kg and MK8776 32 mg/kg qweek x 4 doses). Animals were monitored for cytotoxicity, and tumors were measured weekly with ultrasound. Response to gemcitabine and to combination therapy was correlated to immunohistochemistry of γH2AX and immunoblotting for p345-Chk1 and p296-Chk1. Results: Gemcitabine monotherapy did not affect tumor growth in two models (PH044 and PH048). Significant in vivo response to gemcitabine was seen in PH070 and PH080. Significant growth attenuation but not tumor regression was seen in PH110. MK8776 did not have any effect on tumor growth as monotherapy or in combination with gemcitabine in the gemcitabine resistant model, PH048. In contrast, in a gemcitabine sensitive model, PH080, MK8776 monotherapy significantly attenuated tumor growth, and there was a trend for MK8776 to potentiate the cytotoxic effects of gemcitabine in PH080 (p=0.16). Final tumor weights in the PH080 model after 4 doses of chemotherapy were 1.7 g (90%CI: 1.5-1.9g), 0.3g (90%CI: 0.18-0.35g), and 0.14g (90%CI: 0.08-.19g) in the control, gemcitabine alone, and gemcitabine with MK8776 groups respectively. Decrease in the tumor auto-phosphorylation of Chk1 at Serine-296 was observed in some, but not all models in response to MK8766 treatment. γH2AX increased in response to the addition of MK8776 to gemcitabine. Conclusions: Chk1 inhibition may enhance the activity of gemcitabine in some, but not all ovarian tumors. Further work is needed to find markers that will predict response to Chk1 inhibitors to help select patients for future clinical trials. While pChk1-S296 previously demonstrated potential utility as a biomarker of Chk1 inhibition, in vivo assessments of its differential expression may demonstrate the unreliability of this marker. This work supports the use of patient derived tumorgrafts in drug development for ovarian cancer. Citation Format: A Kumar, S Weroha, M Becker, X Hou, S Greiner, L Karnitz, P Haluska. Chk1 inhibitor (MK8776) enhances cytotoxicity of gemcitabine in select patient-derived ovarian tumorgraft models [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1419.

Abstract Ovarian cancer is the most lethal gynecologic malignancy and the fifth leading cause of cancer deaths among women. The current standard of care post surgical cytoreduction is combination platinum/taxane chemotherapy. The initial response varies widely; subsets of carcinomas demonstrate resistance or sensitivity from the onset. The underlying cause of this response heterogeneity remains incompletely understood. Patient-derived xenografts (PDX) serve as useful in vivo models to study molecular response markers and test the efficacy of targeted therapies. Our group has demonstrated a high engraftment rate (>70%) of ovarian cancer PDXs (Avatars) by injecting treatment naïve patient tumor directly into the peritoneal cavity of an in immunocompromised mouse host in an effort to better mimic the anatomic context by which ovarian cancer naturally develops. We now have 328 engrafted Avatar models representing the wide range of ovarian cancer subtypes, including serous (65%), mixed epithelial (10%), endometrioid (7%), clear cell (4%), mucinous (3%), carcinosarcoma (1%) and other (10%). Using these models, we are performing a massively parallel sequencing strategy referred to as BROCA-HR to detect all mutation classes (e.g. gene rearrangements, copy number variations, etc.) and gene aberrations within the Fanconi Anemia-BRCA homologous recombination (HR), non-homologous end joining (NHEJ), PTEN, and DNA Mismatch repair pathways. To date, 148 Avatar models have undergone BROCA sequencing. Observed deleterious mutations included 12 BRCA1 (8%), 6 BRCA2 (4%), and 4 PIK3CA (3%); additional loss of function mutations were also evident in the following genes: ATM, RAD51C, FANCM, FANCD2, FANCA, CHEK2, PALB2, MHS6, CDK12 and GEN1. These models are representative of mutations seen in the TCGA mutation set. Models harboring said mutations are currently being tested with platinum agents and/or PARP inhibitors. Taken together, the Avatars represent a high throughput model system for pre-clinical testing in vivo that effectively recapitulates ovarian cancer (e.g. mutations in BRCA1, BRCA2 and other DNA damage response proteins). We have been able to establish avatars at a high rate, including those with mutations in BRCA1, BRCA2 and other DNA damage response genes. These models will be a unique resource for future studies of biomarkers and novel therapeutic approaches. This work is funded by the Ovarian Cancer Research Fund (750563), Mayo Ovarian SPORE (CA136393), National Cancer Institute (RO1 CA184502). Note: This abstract was not presented at the meeting. Citation Format: Kunal A. Lodhia, Marc A. Becker, Xiaonan Hou, Kimberly R. Kalli, Maria I. Harrell, Elizabeth M. Swisher, John S. Weroha, Paul Haluska. Characterization of 148 ovarian cancer tumografts (Avatars) using BROCA-HR deep sequencing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1474. doi:10.1158/1538-7445.AM2015-1474