Upfront boost to gross disease followed by elective pelvic radiation improves compliance to radiation therapy delivery metrics in locally advanced vulvar cancer

Locally advanced cancer of the vulva (LACV) is commonly diagnosed in older women (>65 years), and is treated using combined multimodality therapy (CMT) that includes radiation therapy (RT). Compliance to optimal RT metrics, including completion of > 20 fractions, overall treatment duration of < 8 weeks (56 days), and < 1 week intra-treatment break is associated with better disease outcomes. However, published results note that a significant number of patients with LACV do not adhere to these metrics. The aim of our study is to evaluate whether a modified sequence of RT delivery, treating the localized boost volume upfront followed by the larger elective nodal volume is associated with improved compliance to optimal RT delivery metrics.

TAK-676: A Novel Stimulator of Interferon Genes (STING) Agonist Promoting Durable IFN-dependent Antitumor Immunity in Preclinical Studies

Oncology therapies targeting the immune system have improved patient outcomes across a wide range of tumor types, but resistance due to an inadequate T-cell response in a suppressive tumor microenvironment (TME) remains a significant problem. New therapies that activate an innate immune response and relieve this suppression may be beneficial to overcome this hurdle. TAK-676 is a synthetic novel stimulator of interferon genes (STING) agonist designed for intravenous administration. Here we demonstrate that TAK-676 dose-dependently triggers activation of the STING signaling pathway and activation of type I interferons. Furthermore, we show that TAK-676 is a highly potent modulator of both the innate and adaptive immune system and that it promotes the activation of dendritic cells, natural killer cells, and T cells in preclinical models. In syngeneic murine tumor models in vivo, TAK-676 induces dose-dependent cytokine responses and increases the activation and proliferation of immune cells within the TME and tumor-associated lymphoid tissue. We also demonstrate that TAK-676 dosing results in significant STING-dependent antitumor activity, including complete regressions and durable memory T-cell immunity. We show that TAK-676 is well tolerated, exhibits dose-proportional pharmacokinetics in plasma, and exhibits higher exposure in tumor. The intravenous administration of TAK-676 provides potential treatment benefit in a broad range of tumor types. Further study of TAK-676 in first-in-human phase I trials is ongoing.

Significance

TAK-676 is a novel systemic STING agonist demonstrating robust activation of innate and adaptive immune activity resulting in durable antitumor responses within multiple syngeneic tumor models. Clinical investigation of TAK-676 is ongoing.

Identification of Novel Carbocyclic Pyrimidine Cyclic Dinucleotide STING Agonists for Antitumor Immunotherapy Using Systemic Intravenous Route

Stimulator of Interferon Genes (STING) plays an important role in innate immunity by inducing type I interferon production upon infection with intracellular pathogens. STING activation can promote increased T-cell activation and inflammation in the tumor microenvironment, resulting in antitumor immunity. Natural and synthetic cyclic dinucleotides (CDNs) are known to activate STING, and several synthetic CDN molecules are being investigated in the clinic using an intratumoral administration route. Here, we describe the identification of STING agonist 15a, a cyclic dinucleotide structurally diversified from natural ligands with optimized properties for systemic intravenous (iv) administration. Our studies have shown that STING activation by 15a leads to an acute innate immune response as measured by cytokine secretion and adaptive immune response via activation of CD8+ cytotoxic T-cells, which ultimately provides robust antitumor efficacy.

Abstract 1493: LonP1 is required for tumor maintenance and growth

Proper mitochondrial function is critical for energy production and the cycling of metabolites required for tumor establishment and growth. LonP1 is an ATP-dependent serine protease that is critical for maintaining mitochondrial protein homeostasis by degrading misfolded and damaged proteins in the mitochondrial matrix. Knockdown of LonP1 has been shown to reduce tumorogenesis and is consistent with the model that requires properly functioning mitochondria for tumor establishment. It is unclear what the role of LonP1 is in tumor maintenance and growth from an established tumor, therefore the LonP1 gene was mutated and complemented by a doxycycline-inducible copy of LonP1. These complementation clones have the ability to establish tumors in vivo in the presence of doxycycline, however upon doxycycline withdrawal the tumors regress and show evidence of apoptosis. These xenograft lines permit unique insight into not only potential LonP1 substrates but also the direct and indirect effects from loss of mitochondrial matrix protein homeostasis. Comparison and contrast of these complemented cell lines in vitro and in vivo by expression and proteomic analysis will be discussed.

Citation Format: Benjamin S. Amidon, Dongyun Wu, John Bradley, Jingya Ma, Christopher Tsu, Elizabeth Carideo-Cunniff, Vihren Kolev, James Garnsey, Pooja Shah, Erik Koenig, Hua Liao, Courtney Cullis. LonP1 is required for tumor maintenance and growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1493. doi:10.1158/1538-7445.AM2017-1493

Carcinosarcoma of the ovary: a single institution experience and review of the literature

PURPOSE

To evaluate the management and outcome in patients with advanced stage primary carcinosarcoma (CS) of the ovary in a single institution.

MATERIALS AND METHODS

The authors performed a retrospective analysis of all patients treated for CS of the ovary between 1994 and 2011. The medical records, operative reports and pathology records were abstracted for baseline characteristics, surgical staging, degree of cytoreduction and chemotherapy regimens used. Standard statistical methods for analysis of the data were used.

RESULTS

A total of 33 patients with ovarian CS were identified. Of these, 28 records were available for analysis. One patient was Stage I (3.5%), two were Stage II (11.1%), 20 were Stage III (71.4%), and five (17.9%) were Stage IV. The early stage (Stage I and II) patients were excluded from analysis. Of the 25 advanced stage (III and IV) patients, 21 (84.0%) were optimally cytoreduced to a residual disease of < one cm and four (16.0%) were suboptimally cytoreduced. The median progression free survival (PFS) and overall survival (OS) were ten and 21 months, respectively, for advanced stages. Twenty-one (75%) patients received adjuvant chemotherapy and 62% (13 of 21) of treated patients received paclitaxel/carboplatin (T/C) as first-line chemotherapy. The median PFS and OS were 15.6 and 31.7 months, respectively, for those treated with T/C. There was no.difference in PFS (p = 0.42) and OS (p = 0.91) between the patients who received T/C vs. other chemotherapy regimens as a first-line adjuvant chemotherapy. Patients with optimal cytoreduction had an improved PFS compared to those with suboptimal cytoreduction (ten vs. four monthsp = 0.015); however, there was no difference in OS (21 vs. 13 p = 0.117). The two-year OS was 48.0%. In the preset study, PFS was improved in patients who were optimally cytoreduced at the time of diagnosis.

CONCLUSION

T/C is an active regimen in the treatment of ovarian CS and has the potential to be the backbone for addition of biologic targeted therapies in the future. For advanced ovarian CS the authors recommend optimal cytoreductive surgery followed by T/C chemotherapy.

Detection and correlation of pre-operative, frozen section, and final pathology in high-risk endometrial cancer

PURPOSE

To evaluate sensitivity and specificity of pre-operative and frozen section pathologic evaluation (FSA) in predicting high-risk (HR) histology endometrial cancer.

MATERIALS AND METHODS

A retrospective analysis was performed on all patients diagnosed with endometrial cancer at a single institution. Medical records were abstracted for baseline characteristics, surgical reports for staging, and final histology was confirmed by a gynecologic pathologist.

RESULTS

868 patients were identified. Of these, 118 had Grade 3 endometrioid, 36 clear cell carcinoma (CCC), 47 carcinosarcoma (CS), and 84 uterine papillary serous carcinoma (UPSC) histology. Endometrial biopsy (EMB) had an overall sensitivity of 90%, 77% for low grade, 78% for HR, with a specificity of 0%. For dilation and curettage (D&C), overall sensitivity was 85%, 69% for low grade, and 77% for HR. Specificity was 33%. Sensitivities for combined pre-operative testing for G3 endometrioid, CCC, CS, and UPSC were: 56%, 28%, 72%, and 60%, respectively. For frozen section analysis (FSA), overall sensitivity was 77%, and 67% for low and high grade. For G3 endometrioid, CCC, CS, and UPSC, sensitivities were 57%, 20%, 74%, 32%, respectively. Specificity was 95%. FSA identified an additional six patients (8%) with UPSC, CCC or CS that were pre-operatively low risk, providing an 8% improvement in sensitivity but decreased specificity.

CONCLUSIONS

Pre-operative EMB and D&C are overall very sensitive for detecting endometrial cancer; however, sensitivity decreases with HR histology. Pre-op testing will miss 28% of HR diagnoses and FSA provides an opportunity to identify some patients with UPSC, CCC, and CS. If pre-operative results suggest HR cancer, the surgeon should proceed with comprehensive surgical staging without an FSA.

Small-Molecule Reactivation of Mutant p53 to Wild-Type-like p53 through the p53-Hsp40 Regulatory Axis

TP53 is the most frequently mutated gene in human cancer, and small-molecule reactivation of mutant p53 function represents an important anticancer strategy. A cell-based, high-throughput small-molecule screen identified chetomin (CTM) as a mutant p53 R175H reactivator. CTM enabled p53 to transactivate target genes, restored MDM2 negative regulation, and selectively inhibited the growth of cancer cells harboring mutant p53 R175H in vitro and in vivo. We found that CTM binds to Hsp40 and increases the binding capacity of Hsp40 to the p53 R175H mutant protein, causing a potential conformational change to a wild-type-like p53. Thus, CTM acts as a specific reactivator of the p53 R175H mutant form through Hsp40. These results provide new insights into the mechanism of reactivation of this specific p53 mutant.

Preoperative magnetic resonance and intraoperative ultrasound fusion imaging for real-time neuronavigation in brain tumor surgery

PURPOSE

Brain shift and tissue deformation during surgery for intracranial lesions are the main actual limitations of neuro-navigation (NN), which currently relies mainly on preoperative imaging. Ultrasound (US), being a real-time imaging modality, is becoming progressively more widespread during neurosurgical procedures, but most neurosurgeons, trained on axial computed tomography (CT) and magnetic resonance imaging (MRI) slices, lack specific US training and have difficulties recognizing anatomic structures with the same confidence as in preoperative imaging. Therefore real-time intraoperative fusion imaging (FI) between preoperative imaging and intraoperative ultrasound (ioUS) for virtual navigation (VN) is highly desirable. We describe our procedure for real-time navigation during surgery for different cerebral lesions.

MATERIALS AND METHODS

We performed fusion imaging with virtual navigation for patients undergoing surgery for brain lesion removal using an ultrasound-based real-time neuro-navigation system that fuses intraoperative cerebral ultrasound with preoperative MRI and simultaneously displays an MRI slice coplanar to an ioUS image.

RESULTS

58 patients underwent surgery at our institution for intracranial lesion removal with image guidance using a US system equipped with fusion imaging for neuro-navigation. In all cases the initial (external) registration error obtained by the corresponding anatomical landmark procedure was below 2 mm and the craniotomy was correctly placed. The transdural window gave satisfactory US image quality and the lesion was always detectable and measurable on both axes. Brain shift/deformation correction has been successfully employed in 42 cases to restore the co-registration during surgery. The accuracy of ioUS/MRI fusion/overlapping was confirmed intraoperatively under direct visualization of anatomic landmarks and the error was < 3 mm in all cases (100 %).

CONCLUSION

Neuro-navigation using intraoperative US integrated with preoperative MRI is reliable, accurate and user-friendly. Moreover, the adjustments are very helpful in correcting brain shift and tissue distortion. This integrated system allows true real-time feedback during surgery and is less expensive and time-consuming than other intraoperative imaging techniques, offering high precision and orientation.

High-throughput, high-content screening for novel pigmentation regulators using a keratinocyte/melanocyte co-culture system

Skin pigmentation is a complex process including melanogenesis within melanocytes and melanin transfer to the keratinocytes. To develop a comprehensive screening method for novel pigmentation regulators, we used immortalized melanocytes and keratinocytes in co-culture to screen large numbers of compounds. High-throughput screening plates were subjected to digital automated microscopy to quantify the pigmentation via brightfield microscopy. Compounds with pigment suppression were secondarily tested for their effects on expression of microphthalmia transcription factor (MITF) and several pigment regulatory genes, and further validated in terms of non-toxicity to keratinocytes/melanocytes and dose-dependent activity. The results demonstrate a high-throughput, high-content screening approach, which is applicable to the analysis of large chemical libraries using a co-culture system. We identified candidate pigmentation inhibitors from 4000 screened compounds including zoxazolamine, 3-methoxycatechol and alpha-mangostin, which were also shown to modulate expression of MITF and several key pigmentation factors and are worthy of further evaluation for potential translation to clinical use.

Small GTPase RhoE/Rnd3 is a critical regulator of Notch1 signaling

Aberrations of Notch signaling have been implicated in a variety of human cancers. Oncogenic mutations in NOTCH1 are common in human T-cell leukemia and lymphomas. However, loss-of-function somatic mutations in NOTCH1 arising in solid tumors imply a tumor suppressor function, which highlights the need to understand Notch signaling more completely. Here, we describe the small GTPase RhoE/Rnd3 as a downstream mediator of Notch signaling in squamous cell carcinomas (SCC) that arise in skin epithelia. RhoE is a transcriptional target of activated Notch1, which is attenuated broadly in SCC cells. RhoE depletion suppresses Notch1-mediated signaling in vitro, rendering primary keratinocytes resistant to Notch1-mediated differentiation and thereby favoring a proliferative cell fate. Mechanistic investigations indicated that RhoE controls a key step in Notch1 signaling by mediating nuclear translocation of the activated portion of Notch1 (N1IC) through interaction with importins. Our results define RhoE as a Notch1 target that is essential for recruitment of N1IC to the promoters of Notch1 target genes, establishing a regulatory feedback loop in Notch1 signaling. This molecular circuitry may inform distinct cell fate decisions to Notch1 in epithelial tissues, where carcinomas such as SCC arise.

Virtual navigator automatic registration technology in abdominal application

Real-time Ultrasound (US) image fusion with a pre-acquired second imaging dataset - Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and/or CT/PET - has become widely used in recent years for both diagnosis and image-guided interventional procedures. Liver and kidneys are the main focused anatomical districts, related to abdominal application. There are still nowadays some drawbacks, regarding the adoption of the fusion imaging technique in everyday practice especially regarding its ease of use and the time needed in order to obtain a precise real-time fusion between US and the second imaging modality. The present work is a preliminary study on the feasibility and practical use of an Automatic registration algorithm for CT-US real-time fusion imaging. Data obtained by tests performed on a Doppler phantom, for the assessment of the precision of the registration procedure and in-vivo Automatic registration tests, are presented.

Abstract 236: Pharmacological and genetic inhibition of FAK attenuates cancer stem cell function in vitro and in vivo

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that orchestrates cell signaling through integrins and growth factor receptors. FAK has been implicated in multiple steps of carcinogenesis including tumor initiation, growth and metastasis. Amplification and overexpression of FAK have been observed in multiple aggressive human cancers including breast and ovarian. VS-4718 is a potent and selective FAK kinase inhibitor that was previously shown by us to exhibit preferential inhibitory activities on breast cancer stem cells. We have further extended our investigation of the role of FAK on cancer stem cells to other solid tumors and report here that pharmacological attenuation of FAK activity by VS-4718 or RNAi-mediated depletion of FAK exhibits preferential inhibitory effects on cancer stem cells.

To determine if FAK plays a role in the biology of cancer stem cells, we depleted FAK expression in breast, ovarian and mesothelioma cancer cell lines by RNAi. Our results indicated that shRNA-mediated knock-down of FAK inhibits tumorsphere formation in vitro. In parallel, VS-4718 was evaluated in a multitude of cancer stem cell assays both in vitro and in vivo. Pre-treatment of SUM159 cells with VS-4718 in matrigel reduced the percentage of ALDEFLUOR+ cancer stem cells and side population (SP). Similar effects were observed in ovarian cancer cell lines OVCAR-8 and OVCAR-5 where VS-4718 inhibited cancer stem cells as measured by multiple CSC assays. In an analogous fashion, VS-4718 also reduced the proportion of the ALDEFLUOR+ cells in H2052 human mesothelioma cells. In direct contrast, standard-of-care agents paclitaxel, carboplatin or pemetrexed increased the percentage of cancer stem cells, suggesting these agents do not effectively target cancer stem cells. Importantly combination of VS-4718 with standard-of-care agents attenuated chemotherapy-induced increases in the percentage of cancer stem cells in vitro in all three cancer models.

The in vivo effect of VS-4718 on cancer stem cells was evaluated in SUM159 and MDA-MB-231 human triple negative breast cancer xenograft models. Following systemic administration, VS-4718 significantly reduced the proportion of cancer stem cells in tumors as evidenced by decreases in the percentage of ALDEFLUOR+ cells and tumorsphere-forming efficiency relative to vehicle-treated tumors and significantly abrogated tumor-initiating capabilities of cancer cells in a limiting dilution re-implantation assay.

In summary, our results indicate the importance of FAK in the self-renewal of cancer stem cells in vitro and in vivo, and support the clinical development of FAK inhibitors to target cancer stem cells for the treatment of multiple cancers.

Citation Format: Vihren Kolev, Quentin Wright, Christian Vidal, Irina Shapiro, Mahesh Pavdal, Mitchell Keegan, Qunli Xu, Jonathan Pachter. Pharmacological and genetic inhibition of FAK attenuates cancer stem cell function in vitro and in vivo. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 236. doi:10.1158/1538-7445.AM2013-236

A positive FGFR3/FOXN1 feedback loop underlies benign skin keratosis versus squamous cell carcinoma formation in humans

Seborrheic keratoses (SKs) are common, benign epithelial tumors of the skin that do not, or very rarely, progress into malignancy, for reasons that are not understood. We investigated this by gene expression profiling of human SKs and cutaneous squamous cell carcinomas (SCCs) and found that several genes previously connected with keratinocyte tumor development were similarly modulated in SKs and SCCs, whereas the expression of others differed by only a few fold. In contrast, the tyrosine kinase receptor FGF receptor-3 (FGFR3) and the transcription factor forkhead box N1 (FOXN1) were highly expressed in SKs, and close to undetectable in SCCs. We also showed that increased FGFR3 activity was sufficient to induce FOXN1 expression, counteract the inhibitory effect of EGFR signaling on FOXN1 expression and differentiation, and induce differentiation in a FOXN1-dependent manner. Knockdown of FOXN1 expression in primary human keratinocytes cooperated with oncogenic RAS in the induction of SCC-like tumors, whereas increased FOXN1 expression triggered the SCC cells to shift to a benign SK-like tumor phenotype, which included increased FGFR3 expression. Thus,we have uncovered a positive regulatory loop between FGFR3 and FOXN1 that underlies a benign versus malignant skin tumor phenotype.

The prognostic significance of supradiaphragmatic lymphadenopathy identified on preoperative computed tomography scan in patients undergoing primary cytoreduction for advanced stage epithelial ovarian cancer

e16512

Background: It has been hypothesized and shown in animal studies that the supradiaphragmatic lymph nodes serve as the principal nodes for lymphatic drainage of the entire peritoneal cavity. The purpose of this study was to determine the prognostic significance of enlarged supra-diaphragmatic nodes noted on preoperative computed tomography (CT) scan in patients with advanced epithelial ovarian cancer (EOC). Methods: We performed a retrospective chart review of all patients (pts) with FIGO stage III and IV EOC who had preoperative CT scans of the supradiaphragmatic region and primary cytoreductive surgery at our institution between 1997 and 2004. All scans were retrospectively reviewed by one board-certified radiologist (SM). To evaluate survival, Kaplan-Meier methods were used, with log rank Pvalues for comparisons. Results: A total of 212 eligible pts who underwent attempted primary cytoreduction followed by platinum-based systemic chemotherapy were identified for evaluation. With a median follow-up time of 52 mos, there were 135 deaths and a median overall survival of 48 mos (95% CI: 44–53). Of the 212 pts, 44 (21%) had supradiaphragmatic adenopathy with nodes >1 cm, while 168 (79%) did not have adenopathy in this distribution. None of the 44 pts with adenopathy had the enlarged nodes removed at primary cytoreduction. The median survival was 49 mos for pts with and 48 mos for patients without adenopathy (p = 0.46). In total, 155 (73%) patients underwent optimal cytoreduction (residual disease ≤ 1 cm). In the optimally cytoreduced pts, the median survival for the 125 pts without supradiaphragmatic adenopathy was 52 mos (95%CI: 45–59) compared to 51mos (95%CI: 41–58) for the 30 pts with supradiaphragmatic adenopathy (p = 0.33). Conclusions: Although a previous study has shown that supradiaphragmatic adenopathy was associated with poorer overall survival in EOC patients, our study did not confirm these findings. In our study, enlarged supradiaphragmatic nodes noted on preoperative CT scan did not have significant prognostic impact and therefore their clinical significance remains uncertain.

No significant financial relationships to disclose.

Nomogram for predicting 5-year survival after primary surgery for epithelial ovarian cancer

5523

Background: Nomograms have been shown to be superior to traditional staging systems for predicting an individual's probability of long-term survival. Our objective was to develop a nomogram based on established prognostic factors to predict the probability of 5-year disease-specific survival (DSS) after primary surgery for patients with epithelial ovarian cancer (EOC) and to compare its predictive accuracy with the currently used FIGO staging system. Methods: We identified all pts with EOC who had their primary staging/cytoreductive surgery at our institution from January 1996-December 2004. DSS was estimated using the Kaplan-Meier method. We analyzed 28 clinical and pathologic factors for prognostic significance. Significant factors on univariate analysis were then included in the Cox proportional hazards regression model, which identified the factors to be used to construct the nomogram. The concordance index (CI) was used as an accuracy measure, with bootstrapping to correct for optimistic bias. Calibration plots were constructed. Results: There were 478 evaluable pts on the study. The median age was 58 years (range 25–96). The primary surgeon in all cases was an attending gynecologic oncologist. All patients received platinum-based systemic chemotherapy postop. DSS at 5 years was 52%. The most predictive nomogram was constructed using the following 7 predictor variables: age, ASA status, family history suggestive of hereditary breast/ovarian cancer syndrome, preoperative serum albumin level, FIGO stage, tumor histology, and residual disease status after primary surgery. This nomogram was internally validated using bootstrapping and shown to have excellent calibration with a bootstrap-corrected CI of 0.721. The CI for FIGO staging alone was significantly less at 0.62 (p = 0.002). Conclusions: We developed a nomogram to predict 5-year DSS after primary surgery for EOC. The nomogram uses 7 variables that are readily accessible, assigns a point value to each variable, and then predicts the probability of 5-year survival based on the total point value for an individual patient. This tool is more accurate than FIGO staging and should be useful for patient counseling, clinical trial eligibility determination, postop management, and follow-up.

No significant financial relationships to disclose.