Heterogeneity Of Tumor Response Research Articles

Nanotheranostic Strategies for Cancer Immunotherapy.

Despite advancements in cancer immunotherapy, heterogeneity in tumor response impose barriers to successful treatments and accurate prognosis. Effective therapy and early outcome detection are critical as toxicity profiles following immunotherapies can severely affect patients' quality of life. Existing imaging techniques, including positron emission tomography, computed tomography, magnetic resonance imaging, or multiplexed imaging, are often used in clinics yet suffer from limitations in the early assessment of immune response. Conventional strategies to validate immune response mainly rely on the Response Evaluation Criteria in Solid Tumors (RECIST) and the modified iRECIST for immuno-oncology drug trials. However, accurate monitoring of immunotherapy efficacy is challenging since the response does not always follow conventional RECIST criteria due to delayed and variable kinetics in immunotherapy responses. Engineered nanomaterials for immunotherapy applications have significantly contributed to overcoming these challenges by improving drug delivery and dynamic imaging techniques. This review summarizes challenges in recent immune-modulation approaches and traditional imaging tools, followed by emerging developments in three-in-one nanoimmunotheranostic systems co-opting nanotechnology, immunotherapy, and imaging. In addition, a comprehensive overview of imaging modalities in recent cancer immunotherapy research and a brief outlook on how nanotheranostic platforms can potentially advance to clinical translations for the field of immuno-oncology is presented.

Critical issues in pathologic evaluation of pancreatic ductal adenocarcinoma resected after neoadjuvant treatment: a narrative review.

Preoperative neoadjuvant therapy (NAT) is increasingly used in the treatment of patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC). Because NAT often induces heterogeneous tumor response and extensive fibrosis both in tumor and adjacent pancreatic tissue, pathologic assessment of posttherapy pancreatectomy specimens is challenging. A limited number of studies examined the optimal grossing and sampling methods, tumor response grading (TRG), and the prognostic value of posttherapy tumor (ypT) and lymph node (ypN) stages of treated PDAC patients. In this review, we will provide an overview of the current status and critical issues in pathologic evaluation of PDAC resected after NAT. In PubMed, Google Scholar and Web of Science, we reviewed existing English literature (published up to December 2021) highlighting the most recent ones using electronic databases and authors' experience to outline the challenging aspects and new perspectives on pathologic assessment of the treated PDAC. The recent recommendations from the Pancreatobiliary Pathology Society (PBPS) provide the much-needed guidelines for systematic and standardized pathologic evaluation and reporting of treated PDAC for optimal patient care. For treated PDAC, tumor size measured by gross and radiology is not reliable. Histologic validation of tumor size on consecutive mapping sections is recommended for accurate ypT stage. A tumor size of 1.0 cm seems to be a better cutoff for ypT2 for treated PDACs. The published data suggested that the MD Anderson Cancer Center (MDA) TRG system is easy to use, has a better interobserver agreement and better correlation with patient prognosis compared to the College of American Pathologists (CAP) and Evans grading systems and may be used as an alternative TRG system for the CAP cancer protocol. Systemic and standardized grossing and sampling are essential for accurate pathologic evaluation and reporting for optimal care of PDAC patients who received NAT. Future studies on optimal sampling and integration of histopathology with artificial intelligence (AI), molecular and immunohistochemical markers are needed for better and personalized care of treated PDAC patients.

Epithelioid Pleural Mesothelioma Is Characterized by Tertiary Lymphoid Structures in Long Survivors: Results from the MATCH Study.

Pleural mesothelioma (PM) is an aggressive tumor with few therapeutic options. Although patients with epithelioid PM (ePM) survive longer than non-epithelioid PM (non-ePM), heterogeneity of tumor response in ePM is observed. The role of the tumor immune microenvironment (TIME) in the development and progression of PM is currently considered a promising biomarker. A few studies have used high-throughput technologies correlated with TIME evaluation and morphologic and clinical data. This study aimed to identify different morphological, immunohistochemical, and transcriptional profiles that could potentially predict the outcome. A retrospective multicenter cohort of 129 chemonaive PM patients was recruited. Tissue slides were reviewed by dedicated pathologists for histotype classification and immunophenotype of tumor-infiltrating lymphocytes (TILs) and lymphoid aggregates or tertiary lymphoid structures (TLS). ePM (n = 99) survivors were further classified into long (>36 months) or short (<12 months) survivors. RNAseq was performed on a subset of 69 samples. Distinct transcriptional profiling in long and short ePM survivors was found. An inflammatory background with a higher number of B lymphocytes and a prevalence of TLS formations were detected in long compared to short ePM survivors. These results suggest that B cell infiltration could be important in modulating disease aggressiveness, opening a pathway for novel immunotherapeutic approaches.

Onvansertib and paclitaxel combined in platinum-resistant ovarian carcinomas.

Background:Ovarian carcinoma is extremely sensitive to (platinum-based) chemotherapy; however, most patients will relapse with platinum-resistant disease, badly affecting their prognosis. Effective therapies for relapsing resistant tumors are urgently needed.Methods:We used patient-derived xenografts (PDXs) of ovarian carcinoma resistant to cisplatin (DDP) to test in vivo the combination of paclitaxel (15 mg/kg i.v. once a week for 3 weeks) and onvansertib, a plk1 inhibitor, (50 mg/kg orally 4 days a week for 3 weeks). The PDX models were subcutaneously (s.c.) or orthotopically transplanted in nude mice and antitumor efficacy was evaluated as tumor growth inhibition and survival advantages of the combination over untreated and single agent treatment.Results:The combination of onvansertib and paclitaxel was very well tolerated with weight loss no greater than 15% in the combination group compared with the control group. In the orthotopically transplanted PDXs, single onvansertib and paclitaxel treatments prolonged survival; however, the combined treatment was much more active, with median survival from three- to six-fold times that of untreated mice. Findings were similar with the s.c. transplanted PDX, though there was greater heterogeneity in tumor response. Ex vivo tumors treated with the combination showed greater induction of γH2AX, marker of apoptosis and DNA damage, and pSer10H3, a marker of mitotic block.Conclusion:The efficacy of onvansertib and paclitaxel combination in these preclinical ovarian cancer models supports the clinical translatability of this combination as an effective therapeutic approach for platinum-resistant high-grade ovarian carcinoma.

Management of heterogeneous tumor response patterns to immunotherapy in patients with metastatic melanoma.

Immunotherapy has revolutionized the treatment of metastatic melanoma. Response to therapy can be complex to evaluate, as Response Evaluation Criteria in Solid Tumor (RECIST) does not capture heterogeneous responses. In this retrospective single-institution analysis, we describe the management, clinicopathological characteristics, RECIST and disease course of metastatic melanoma patients with a heterogeneous response to first-line anti-CLTA-4 and/or anti-PD-1 between September 2011 and September 2020. In 196 patients, 37 had a heterogeneous response to immunotherapy (19%). Distinct identified responses included a mixed response (MR) (15%), pseudoprogressive disease (PP) (3%), and a sarcoid-like reaction (2%). Patients with a MR and possibly no response to therapy (MR-NR) had a higher median lactic acid dehydrogenase (LDH) (P = 0.01), were more often male (P = 0.04), had more involved disease sites (P = 0.01), and had brain metastasis more frequently (P = 0.02). MR patients with later response to therapy (MR-R) and PP patients had a longer overall survival of 1.7 [95% confidence interval (CI), 1.1-2.7] and 1.6 years (95% CI, 1.3-2.0) versus MR-NR 1.2 (0.7-1.7) (P < 0.01). In this cohort study, we identified prognostic clinical characteristics that can contribute to clinical decision-making for patients with a MR. Additionally, patients with pseudoprogression had benefited from therapy continuation, suggesting the importance of not halting therapy early in case of suspected PP. The male sex, more involved disease sites, brain metastasis and had a higher median LDH were associated with a poor survival for patients with a MR, suggesting that these clinical variables could be used to predict whether a mixed responder will possibly respond to therapy.

Response to Immune Checkpoint Inhibitors in Recurrent or Metastatic Esophageal Squamous Cell Carcinoma May Be Affected by Tumor Sites

Introduction: Heterogeneous tumor response has been reported in cancer patients treated with immune checkpoint inhibitors (ICIs). This study investigated whether the tumor site is associated with the response to ICIs in patients with recurrent or metastatic esophageal squamous cell carcinoma (ESCC). Methods: Patients with ESCC who had measurable tumors in the liver, lung, or lymph node (LN) according to the response evaluation criteria in solid tumors (RECIST) 1.1 and received ICIs at 2 medical centers in Taiwan were enrolled. In addition to RECIST 1.1, tumor responses were determined per individual organ basis according to organ-specific criteria modified from RECIST 1.1. Fisher test or χ² test was used for statistical analysis. Results: In total, 37 patients were enrolled. The overall response rate per RECIST 1.1 was 13.5%. Measurable tumors in the LN, lung, and liver were observed in 26, 17, and 13 patients, respectively. The organ-specific response rates were 26.9%, 29.4%, and 15.4% for the LN, lung, and liver tumors, respectively (p = 0.05). The organ-specific disease control rates were 69.2%, 52.9%, and 21.1% for the LN, lung, and liver tumors, respectively (p = 0.024). Five (27.8%) among 18 patients harboring at least 2 involved organs had heterogeneous tumor response. Conclusion: The response and disease control to ICIs may differ in ESCC tumors located at different metastatic sites, with a lesser likelihood of response and disease control in metastatic liver tumors than in tumors located at the LNs and lung.

Quantitative ultrasound to better evaluate heterogeneous tumor response to therapy

Heterogenity of tumor structure and function (e.g., stromal density, vascularization, and oxygen distribution) can influence local cellular proliferation and therapeutic resistance. Emerging ultrasound imaging techniques can map parameters related to these features but such approaches are not yet in standard clinical practice. The goal of our work is to develop robust protocols to provide more complete information during therapy by quantitatively mapping and interpreting tumor heterogeneity using emerging ultrasonic techniques. Within murine tumor models Shear Wave Elastography (SWE), Contrast-Enhanced Ultrasound (CEUS) and Quantitative Ultrasound (QUS) techniques have been applied with clinical imaging systems to compare changes observed during anti-angiogenic and cytotoxic therapy as compared to controls. In a Lewis Lung Carcinoma model, mice receiving an anti-angiogenic therapy had the highest levels of necrosis and fibrosis and presented the highest number of correlations between quantitative parameters related to microvascular function and tumor structure. This indirectly demonstrates, for this tumor-type, that quantitative parameters measured with clinical imaging systems can help differentiate tumor therapeutic responses. Promising results with ultrasound localization microscopy and photoacoustics will also be reviewed because of the important new information they offer. Finally, the path towards integration of these quantitative ultrasound techniques in clinical practice will be discussed.

Response to immune checkpoint inhibitors in recurrent/metastatic esophageal squamous cell carcinoma may be affected by tumor site and lesion size.

e16099Background: Heterogeneous tumor response has been reported in cancer patients receiving immune checkpoint inhibitors (ICIs). This study investigated whether or not tumor site and tumor size s...

Utilization of a hybrid finite-element based registration method to quantify heterogeneous tumor response for adaptive treatment for lung cancer patients

Tumor response to radiation treatment (RT) can be evaluated from changes in metabolic activity between two positron emission tomography (PET) images. Activity changes at individual voxels in pre-treatment PET images (PET1), however, cannot be derived until their associated PET-CT (CT1) images are appropriately registered to during-treatment PET-CT (CT2) images. This study aimed to investigate the feasibility of using deformable image registration (DIR) techniques to quantify radiation-induced metabolic changes on PET images. Five patients with non-small-cell lung cancer (NSCLC) treated with adaptive radiotherapy were considered. PET-CTs were acquired two weeks before RT and 18 fractions after the start of RT. DIR was performed from CT1 to CT2 using B-Spline and diffeomorphic Demons algorithms. The resultant displacements in the tumor region were then corrected using a hybrid finite element method (FEM). Bitmap masks generated from gross tumor volumes (GTVs) in PET1 were deformed using the four different displacement vector fields (DVFs). The conservation of total lesion glycolysis (TLG) in GTVs was used as a criterion to evaluate the quality of these registrations. The deformed masks were united to form a large mask which was then partitioned into multiple layers from center to border. The averages of SUV changes over all the layers were 1.0 ± 1.3, 1.0 ± 1.2, 0.8 ± 1.3, 1.1 ± 1.5 for the B-Spline, B-Spline + FEM, Demons and Demons + FEM algorithms, respectively. TLG changes before and after mapping using B-Spline, Demons, hybrid-B-Spline, and hybrid-Demons registrations were 20.2%, 28.3%, 8.7%, and 2.2% on average, respectively. Compared to image intensity-based DIR algorithms, the hybrid FEM modeling technique is better in preserving TLG and could be useful for evaluation of tumor response for patients with regressing tumors.

A novel morphologic and metabolic feature fused treatment response evaluation pipeline for pancreatic adenocarcinoma patients.

311 Background: Adaptive radiation therapy for pancreatic adenocarcinoma (PA) relies on accurate treatment response assessment. Traditional RECIST criteria poorly characterize tumors with complex morphological features, while PET imaging inefficiently detects tumors with intrinsically low standardized uptake value (SUV). Here, we performed regional comparisons of 3D intact PA surfaces pre and post chemoradiotherapy (CRT) utilizing surface measurements containing both morphological and metabolic features to better assess response. Methods: Twenty-one locally advanced PA patients with pre- and 6-8 week post-CRT 18F FDG-PET/CT scans were evaluated. Boundaries of initial and post-CRT tumors were manually defined on respective CT images. On each of the tumors, 3D meshes were generated, followed by surface based registration to achieve vertex-wise correspondence. For each surface vertex, a multivariate vector was formed from two components: anatomic (deformation tensors resulted from surface registration), and metabolic (regional SUV obtained from radius to surface projections). To assess tumor response, paired mahabanobis distance (Mdist) between pre- and post-CRT tumor surfaces with previously formed multivariate vectors were calculated for each patient. Mdist was evaluated using Cox analysis correlated with overall survival (OS) and compared with measurements based on serum CA19-9, volume, SUVmax and SUVmean. Results: Among all the tested parameters, Mdist is the best predictor of OS, with a hazard ratio of 0.437 (p = 0.036). Post-CRT versus pre-CRT ratios based on volume and SUVmax both reached borderline significance (p = 0.0769 and 0.0799, respectively), while CA19-9 and SUVmean failed in predicting OS in our small cohort of patients. Conclusions: We introduced a PET/CT-based novel morphologic and metabolic pipeline for post-CRT response evaluation in locally advanced PA. The fused Mdist outperformed traditional morphologic, metabolic, and physiological measurements in OS prediction. The presented fused model may serve as a new biomarker to better characterize the heterogeneity of tumor response to CRT and a predictive marker for surgical resection.

Investigation of Heterogeneous Tumor Response in Adaptive Radiation Therapy for Patients With Lung Cancer

In PET-guided adaptive radiotherapy (RT), metabolic activity changes at individual voxels cannot be derived until pre-treatment CT (CT1) images are appropriately registered to during-treatment CT (CT2) images. This study aims to investigate the feasibility of using deformable image registration (DIR) techniques to quantify radiation-induced metabolic changes on PET images. Five patients with non-small cell lung cancer (NSCLC) treated with adaptive radiotherapy, were selected. PET/CT image-sets were acquired 2 weeks before RT and 18 fractions after the start of RT. DIR was carried out to register the CT1 to the CT2 using two image intensity-based deformable registration methods: B-spline and diffeomorphic Demons algorithms. The resultant displacements on the bounding box of the tumor were then used as boundary conditions a hybrid finite element method (Bspline/Demons+FEM). Bitmap masks were generated for gross tumor volumes (GTVs) in pre-treatment CT images. Each mask was divided into multiple layers from outer to interior, and changes in metabolic activity were calculated on each layer for different deformable registrations. The quality of these registrations was assessed based on the consistency of metabolic tumor index (MTI) calculated on the original and mapped GTVs. MTI changes before and after mapping using B-Spline, Demons, hybrid-B-Spline, and hybrid-Demons registrations were 20.2%, 28.3%, 8.7%, and 2.2% on average, respectively. Average displacement error was 3.5±0.7mm for B-Spline registration and 2.1±0.4mm for B-Spline+FEM registration. Changes of SUVmean between the pre-RT PET and the during-RT PET were 49.3±13.4% and 40.2±13.3% for hybrid-B-Spline and hybrid-Demons deformation maps. For three of the patients with large tumors, SUV changes averaged in the middle layers of the tumors were about 2 times the changes in the central and peripheral layers, while relative changes in the activity were about 1.3 times in these layers, showing less variation. As opposed to image-intensity-based DIR algorithms, hybrid FEM modeling is independent of image intensity changes induced by tumor regression. Consequently the accuracy of the B-Spline and Demons registrations in the tumor region is improved. The hybrid modeling technique makes it possible to compare metabolic activities between two PET images for patients with tumor regression and reduces the uncertainty in comparing associated voxels in different regions of two images.

Abstract 4189: Homologous recombination pathway-based biomarkers for treatment of non-small cell lung cancer with PARP inhibitors

Abstract Introduction: Clinical trials examining the addition of PARP inhibitors (PARPi) to treatment regimens for non-small cell lung cancer (NSCLC) are underway. Of note, these trials are not biomarker driven, and so any benefit may be obscured due to heterogeneity of tumor responses. The first FDA approved PARPi, olaparib, was approved specifically for ovarian cancer patients with germline mutations in BRCA1 or 2. These patients have tumors that show homologous recombination deficiency (HRD), a DNA damage repair pathway defect that confers synthetic lethality in the setting of PARPi therapy. Whether HRD may serve a biomarker for PARPi sensitivity in NSCLC, however, is unclear. Materials and Methods: Based on prior studies, NSCLC cell lines were classified as 1) HR proficient (A549, NCI-H23, NCI-H460, NCI-H522, NCI-H1299), 2) HR deficient due to early defects in the pathway as evidenced by decreased cisplatin-induced RAD51 focus formation (NCI-H1563, NCI-H1915, NCI-H2087, NCI-H2126) or 3) HR deficient due to late defects in the pathway as evidenced by impaired resolution of ionizing radiation (IR) induced RAD51 and γ-H2AX foci (Calu-1, Calu-6, HCC827, NCI-H520, SK-LU-1). NSCLC cells expressing doxycycline-inducible BRCA1 or 2 shRNA were generated by Tet-pLKO-puro lentiviral transduction. Cell viability assays to determine olaparib IC50 values were performed using CellTiter-Glo and MTS. Gene expression data were extracted from published datasets including CCLE, GSE32665 and TCGA, and expression levels of select genes were assayed by RT-qPCR. Results: BRCA1/2 shRNA knockdown inhibited IR-induced RAD51 focus formation in HR proficient NSCLC cells. This also induced PARPi sensitivity (A549 olaparib IC50 63 µM -&amp;gt; 1.2 µM with BRCA1 and 18 µM -&amp;gt; 3.4 µM with BRCA2 knockdown). Because BRCA alterations are uncommon in NSCLC, however, other HRD biomarkers were explored. There was no statistically significant difference in PARPi sensitivity among cell lines grouped by cisplatin-induced RAD51 focus formation or resolution of IR-induced RAD51 or γ-H2AX foci. BRCA deficient breast and ovarian cancers overexpress POLQ, which drives DNA repair toward non-HR-dependent pathways including alternative end joining. Like these cancers, NSCLC tumors overexpressed POLQ and RAD54L compared to normal lung, p &amp;lt; 0.001. Expression of these two genes correlated highly in multiple datasets, e.g., r² = 0.69 and p &amp;lt; 0.001 in TCGA adenocarcinomas. High RAD54L expression tended to correlate with low olaparib IC50 values, r = -0.56, p = 0.059. NCI-H1299 and SK-LU-1, which showed the highest RAD54L expression, also showed the highest olaparib sensitivity. Conclusion: Although certain HRD biomarkers including RAD51 focus formation and impaired resolution did not predict NSCLC olaparib sensitivity, other potential biomarkers, such as BRCA1/2 loss of function and elevated RAD54L expression, may serve as potential HRD-related biomarkers. Citation Format: Peter V. Deraska, Hunter D. Reavis, Shelby Labe, Alan D. D'Andrea, David Kozono. Homologous recombination pathway-based biomarkers for treatment of non-small cell lung cancer with PARP inhibitors [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 4189. doi:10.1158/1538-7445.AM2017-4189

Effects of Shear Stress Gradients on Ewing Sarcoma Cells Using 3D Printed Scaffolds and Flow Perfusion

In this work, we combined three-dimensional (3D) scaffolds with flow perfusion bioreactors to evaluate the gradient effects of scaffold architecture and mechanical stimulation, respectively, on tumor cell phenotype. As cancer biologists elucidate the relevance of 3D in vitro tumor models within the drug discovery pipeline, it has become more compelling to model the tumor microenvironment and its impact on tumor cells. In particular, permeability gradients within solid tumors are inherently complex and difficult to accurately model in vitro. However, 3D printing can be used to design scaffolds with complex architecture, and flow perfusion can simulate mechanical stimulation within the tumor microenvironment. By modeling these gradients in vitro with 3D printed scaffolds and flow perfusion, we can identify potential diffusional limitations of drug delivery within a tumor. Ewing sarcoma (ES), a pediatric bone tumor, is a suitable candidate to study heterogeneous tumor response due to its demonstrated shear stress-dependent secretion of ligands important for ES tumor progression. We cultured ES cells under flow perfusion conditions on poly(propylene fumarate) scaffolds, which were fabricated with a distinct pore size gradient via extrusion-based 3D printing. Computational fluid modeling confirmed the presence of a shear stress gradient within the scaffolds and estimated the average shear stress that ES cells experience within each layer. Subsequently, we observed enhanced cell proliferation under flow perfusion within layers supporting lower permeability and increased surface area. Additionally, the effects of shear stress gradients on ES cell signaling transduction of the insulin-like growth factor-1 pathway elicited a response dependent upon the scaffold gradient orientation and the presence of flow-derived shear stress. Our results highlight how 3D printed scaffolds, in combination with flow perfusion in vitro, can effectively model aspects of solid tumor heterogeneity for future drug testing and customized patient therapies.

Commentary on Pharmacometrics for Immunotherapy.

This commentary provides an overview of recent examples of pharmacometrics applied during the clinical development of two antagonists of the programmed death‐1 (PD‐1) cell surface receptor, pembrolizumab and nivolumab. Despite the remarkable achievements obtained in predicting the correct dosing schedule from different quantitative approaches, data indicated a great degree of heterogeneity in tumor response. To achieve therapeutic goals the search for predictive biomarkers associated with a lack of response and mechanism‐based combination studies are warranted.

Preclinical progress and first translational steps for a liposomal chemotherapy protocol against adrenocortical carcinoma.

Systemic therapy of adrenocortical carcinoma (ACC) is limited by heterogeneous tumor response and adverse effects. Recently, we demonstrated anti-tumor activity of LEDP-M (etoposide, liposomal doxorubicin, liposomal cisplatin, mitotane), a liposomal variant of EDP-M (etoposide, doxorubicin, cisplatin, mitotane). To improve the therapeutic efficacy and off-target profiles of the clinical gold standard EDP-M, we investigated liposomal EDP-M regimens in different preclinical settings and in a small number of ACC patients with very advanced disease. Short- and long-term experiments were performed on two ACC models (SW-13 and SJ-ACC3) in vivo We evaluated the anti-tumoral effects and off-target profiles of EDP-M, LEDP-M and a novel regimen L(l)EDP-M including liposomal etoposide. Furthermore, the role of plasma microRNA-210 as a therapeutic biomarker and first clinical data were assessed. Classical and liposomal protocols revealed anti-proliferative efficacy against SW-13 (EDP-M P < 0.01; LEDP-M: P < 0.001; L(l)EDP-M: P < 0.001 vs controls), whereas in SJ-ACC3, only EDP-M (P < 0.05 vs controls) was slightly effective. Long-term experiments in SW-13 demonstrated anti-tumor efficacy for all treatment schemes (EDP-M: P < 0.01, LEDP-M: P < 0.05, L(l)EDP-M P < 0.001 vs controls). The analysis of pre-defined criteria leading to study termination revealed significant differences for control (P < 0.0001) and EDP-M (P = 0.003) compared to L(l)EDP-M treatment. Raising its potential for therapy monitoring, we detected elevated levels of circulating microRNA-210 in SW-13 after LEDP-M treatment (P < 0.05). In contrast, no comparable effects were detectable for SJ-ACC3. However, overall histological evaluation demonstrated improved off-target profiles following liposomal regimens. The first clinical data indicate improved tolerability of liposomal EDP-M, thus confirming our results. In summary, liposomal EDP-M regimens represent promising treatment options to improve clinical treatment of ACC.

Abstract 2480: Chronic radiation exposure increases uPA and cMyc expression levels but decreases nMyc expression levels in neuroblastoma cells

Abstract Neuroblastoma is the most common extra-cranial solid tumor in children. Despite aggressive therapy prognosis of high risk neuroblastoma remains guarded and also unpredictable because of heterogeneity of tumor response to treatment. Radio-resistance has been recognized as a significant contributor to aggressive clinical behavior of neuroblastoma. Characterization of genetic alterations have been used for predicting clinical outcome in neuroblastomas and one of the most studied genetic markers in aggressive neuroblastoma is nMyc/MYCN. The MYCN gene belongs to the MYC family of transcription factors and nMyc expression is to a large extent inversely correlated with cMyc expression and nMyc expression is also associated poor clinical outcomes. In this study, we have attempted to correlate the expression of nMyc in neuroblastoma cells NB1691 and SKNBE2 to radiation resistance. We exposed neuroblastoma cells NB1691 and SKNBE2 to chronic radiation doses with a cumulative high energy X-ray radiation dose of 25Gy achieved by dosing at 5Gy increments over a period of 15 days. Cells surviving after the 25Gy cumulative radiation dose were selected and designated as NB1691R and SKNBE2R. Expression levels of nMyc, cMyc and uPA were determined. We observed that the radiation tolerant cells showed at least 164 fold increase in the expression of uPA in NB1691R cells and at least 97 fold increase in SKNBE2R cells. We also observed that the expression levels of nMyc decreased in both NB1691R and SKNBE2R cells to almost undetectable levels. Further, the expression levels of cMyc revealed that NB1691R cells showed a 208 fold increase and SKNBE2R a 71 fold increase when compared to parental cells. We further determined whether the expression of uPA can modulate the expression of nMyc. We silenced uPA expression in NB1691 cells and observed that downregulation of uPA moderately rescued nMyc expression. Cell cycle analysis revealed that acute radiation of NB1691 cells induced accumulation of cells in the G2/M phase and un-radiated NB1691R cells continued to show cells accumulated in the G2/M phase similar to acute radiated NB1691 cells. Our study shows that: 1. Chronic radiation exposure suppresses the expression of nMyc and induces the expression of cMyc. 2. cMyc expression was accompanied with the expression of uPA and suppression of uPA expression moderately rescued the expression of nMyc. Our preliminary findings suggest that chronic exposure to radiation alters the nMyc/cMyc ratio in neuroblastoma cells and induces the expression of the pro-invasive molecule uPA. Citation Format: Manu Gnanamony, David Pinson, Reuben Antony, Karen S. Fernández, Julian Lin, Pushpa A. Joseph, Christopher S. Gondi. Chronic radiation exposure increases uPA and cMyc expression levels but decreases nMyc expression levels in neuroblastoma cells. [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 2480.

Prognostic value of clinical, laboratory and molecular predictors in the formation of personalized approaches to breast cancer treatment.

Background. The death rate from breast cancer in the past 10 years has increased steadily and has won first place in frequency among women. Despite advances in modern oncofarmakology, there is a heterogeneous tumor response to treatment between different patients. The objectives of our study were to evaluate the relationship between tumor response to systemic therapy and general and histological characteristics of patient’s tumors, including molecular subtypes of breast cancer, identify patterns between antropometric parameters of patients, comorbidities, and tumor response to the treatment; to study the effect of hematological, blood biochemical parameters on the results of the treatment of breast cancer. Methods. Molecular subtypes of breast cancer were established among 7521 patients, their changebility or stability in 67. Overall survival data was available for 491 patients with metastatic disease, peculiarities of development of metastases based on RECIST 1.1. criteria - 306. Retrospectively reviewed medical records of 110 patients with inoperable breast cancer (breast cancer) who received systemic therapy for the standard scheme. In the course of treatment were studied indicators such as: medical history of patients, life history, hematology, blood biochemistry, the results of primary and repeated histological and immunohistochemical studies of tumors, determination of molecular subtypes of breast cancer. Results. The distribution of the molecular subtypes of patients were as follows: A luminal - 69% luminal B - 9%, HER-2 / neu-positive - 7%, triple negative - 15%. Accounting factor Ki-67 (≥14%) led to an increase in the frequency of luminal B subtype from 9% to 19% by reducing the luminal A. In 44.8% of patients it was noted a change of molecular subtypes. Targeted therapy (Herceptin) in these patients allowed to overcome unfavorable prognostic background - results in median survival from them (41,3±4,5 months) were higher than in the group without Herceptin (27,4±3,4 months) and higher than the HER-2 / neu-negative patients (38,1±3,0 months). The value of coefficient Spearman rank correlation to tumor response and the factor of menopause, age, general condition of the patient were - 0.174; -0.222; -0.250 (P &lt;0.05), in accordance. The status of regional nodes N and tumor response have the correlation coefficient: - 0,265; (P &lt;0.05), the status of the primary tumor T and metastases M - 0.107; and -0.071 (p&gt; 0.05), in accordance. In the presence of neutropenia at 1 week after treatment it has been revealed significantly better tumor response to treatment - the correlation coefficient: 0.204 (p &lt;0.05). Conclusion. Molecular subtypes detection had shown that HER-2/neu-positive and tripple negative breast cancer demonstrated the most aggresive course of disease. It was found that a more pronounced tumor response to combination chemotherapy can be expected in young patients, pre-menopausal, high ECOG status. The presence of neutropenia has a significantly positive impact on the results of treatment of patients with metastatic breast cancer.

Abstract B1-39: Multi-target drug combinations from single drug responses measured at the level of single cells using Mixture Nested Effects Models (MNEMs) applied to cancer

Abstract Purpose: To identify an optimal drug combination for addressing intratumor heterogeneity by measuring single drug responses at the level of single cells. Background: Drug combination strategies have been derived from drug-drug and drug-target interaction inferences made based on genomic network analysis, such as synthetic lethality network analysis and protein network analysis. A key limitation with these approaches is that they do not account for intratumor heterogeneity. A next generation high throughput single cell technology such as Cytometry Time-of-Flight (CyTOF) has the potential to circumvent this limitation by providing the key information for optimally targeting intratumor heterogeneity within the context of personalized medicine. Methods: We propose a systems level modeling framework for analyzing heterogeneous drug response data across a population of single cells. Our approach, called Mixture Nested Effects Models (MNEM), identifies multi-target drug combinations from single drug effects measured at the level of single cells. MNEM analyzes drug responses among subpopulations (aka clusters) of similar cells, where the subpopulations are defined by cellular surface markers. MNEM infers the nested drug target hierarchy (directed network) from a heterogeneous population of drug effects by combining subpopulation identification, subpopulation matching to infer the drug response pre- and post-treatment, and nested effects modeling for each subpopulation individually or through a mixture of subpopulations. An MNEM infers that Drug A targets are a superset of Drug B targets, if the heterogeneous downstream target effects resulting from Drug B are a noisy subset of those resulting from Drug A. This relationship is represented as a directed edge from Drug A to Drug B. From the graphical model of nested drug effects, a scoring function is superimposed to identify the optimal drug combinations. Results: We apply MNEM to CyTOF drug screening data derived from treating three well-established cancer cell lines: HeLa (ovarian), NCIH460 (lung) and HCT116 (colon) with Mek, mTOR, pP38MAPK, JnK I and PI3K inhibitors at different optimal dose levels in addition to the base line treatment TRAIL, an apoptotic stimulator. MNEM indicates that pP38MAPK and Mek inhibitors are important candidates for targeting the ovarian and lung cancer cell lines. The MNEM analysis from the colon cancer cell line data indicates that several optimal drug regimens may have equivalent efficacy. Survival data from drug combination invitro experiments using clonogenic assays support the results from MNEM. Overall, these analyses suggest that MNEM could be used to optimize drug combinations based on responses from single drugs measured at the single cell level. Conclusion: Intratumor heterogeneity in tumor response, measured at the level of single cells, upon exposure to single drugs may be combined through Mixture Nested Effects Modeling (MNEM) to infer optimal drug combinations. Citation Format: Benedict Anchang, Harris Fienberg, Sean Bendall, Robert Tibshirani, Sylvia K. Plevritis. Multi-target drug combinations from single drug responses measured at the level of single cells using Mixture Nested Effects Models (MNEMs) applied to cancer. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B1-39.

Abstract A2-65: Integrating computational and experimental approaches to build predictive models of the SMG1 kinase network in glioblastoma stem cells

Abstract Glioblastoma multiforme (GBM) is the most common and most aggressive tumor of the central nervous system, with a mean survival of only 12-14 months post diagnosis and treatment. A major reason for the poor prognosis of GBM is attributed to a small population of refractory GBM stem cells (GSC) that have been shown to initiate and sustain tumor growth. Current evidence suggests that GSC preferentially reside in hypoxic niches in the tumor that contribute to maintenance of its stem cell properties such as self-renewal and resistance to therapy. In order to identify targets for achieving effective tumor remission, we have performed an RNAi kinome screen to identify specific kinases that enable the survival of GSCs in hypoxic microenvironment. Only 40% of the hits were common between the two cell lines screened, emphasizing heterogeneity of tumor response that necessitates personalized targeted therapy for GBM. The SMG1 kinase was identified in this screen as a gene that is preferentially inhibitory to one of our GSC lines under hypoxia (1% oxygen). SMG1 is a member of the phosphoinositide-like family of kinases that includes ATM, ATR and mTOR. SMG1 is a potential target for cancer therapy to counteract tumor cell growth and resistance to DNA damaging chemotherapeutic agents due to its role in nonsense mediated decay (NMD) and DNA damage response (DDR) pathways. Our results are therapeutically significant since we found additive growth inhibitory effect of SMG1 knockdown in GSC in the presence of DNA damaging drug Temozolomide (TMZ), the current standard of care for GBM. The Upf1 is an essential NMD factor that is phosphorylated by SMG1 and is also required for DNA damage induced cell cycle S phase progression. Interestingly, our results show that the growth inhibitory effect of SMG1 knockdown correlated with the induction of Upf1 in GS7-2 cells specifically under hypoxia. We assessed the role of downstream mediators in NMD pathway (ATF-4, MAP4K12, SMG7 and p-EIF2alpha) and DDR pathway (p53, p-p53 (Ser 15), p21, ATM, ATR, Chk1, p-Chk1, Chk2, p-Chk2 and MRN complex) to identify critical components of the pathways that contribute to the differential growth inhibition effect. We have used the Cell Collective modeling software platform (BMC Systems Biology, 6, 96) to model the SMG1 signaling network by integrating our data with results in the literature in order to simulate cellular growth and survival of GSC under hypoxia and TMZ induced DNA damage. Our model predicts that the preferential growth inhibitory role of SMG1 inhibition in GS7-2 cells under hypoxia specifically is due to the role of NMD pathway in regulating autophagy and this is currently being tested experimentally in multiple cell lines. The long-term goal of this study will be to develop therapeutic predictions for targeting SMG1 or other kinases from the screen for a given tumor and thereby develop personalized therapies for treating GBM. Citation Format: Sejuti Sengupta, Steven K. Young, Surbhi Goel-Bhattacharya, Brent H. Cochran. Integrating computational and experimental approaches to build predictive models of the SMG1 kinase network in glioblastoma stem cells. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A2-65.

Changes in Skeletal Tumor Activity on (18)F-choline PET/CT in Patients Receiving (223)Radium Radionuclide Therapy for Metastatic Prostate Cancer.

Radium-223 dichloride is an alpha-emitting radiopharmaceutical shown to prolong survival in patients with castrate-resistant prostate cancer (CRPC) and symptomatic skeletal metastases. This report describes in two patientsthe acute changes in bone metastatic activity detected by F-18 choline PET/CT imaging midway during treatment with radium-223 dichloride. In addition to visual and standardized uptake value analysis, changes in the whole-body tumor burden were quantified by measuring the difference in net metabolically active tumor volume (MATV) and total lesion activity (TLA) between pre- and mid-treatment PET scans. After the third dose of radium-223 dichloride, near-total disappearance of abnormal skeletal activity was observed in one case (net MATV change from 260.7 to 0.8cc; net TLA change from 510.7 to 2.1), while a heterogeneous tumor response was observed in the other (net MATV change from 272.2 to 241.3cc; net TLA change from 987.1 to 779.4). Corresponding normalization and persistent elevation in serum alkaline phosphatase levels were observed in these cases, respectively. Further research is needed to determine the predictive value of serial F-18 choline PET/CT imaging in patients receiving radium-223 dichloride for CRPC.