MIF/NR3C2 Axis Regulates Glucose Metabolism Reprogramming in Pancreatic Cancer through MAPK-ERK and AP-1 Pathways

Inflammation and aberrant cellular metabolism are widely recognized as hallmarks of cancer. In pancreatic ductal adenocarcinoma (PDAC), inflammatory signaling and metabolic reprogramming are tightly interwoven, playing pivotal roles in the pathogenesis and progression of the disease. However, the regulatory functions of inflammatory mediators in metabolic reprogramming in pancreatic cancer have not been fully explored. Earlier, we demonstrated that pro-inflammatory mediator macrophage migration inhibitory factor (MIF) enhances disease progression by inhibiting its downstream transcriptional factor nuclear receptor subfamily 3 group C member 2 (NR3C2). Here, we provide evidence that MIF and NR3C2 interactively regulate metabolic reprogramming, resulting in MIF-induced cancer growth and progression in PDAC. MIF positively correlates with the HK1 (hexokinase 1), HK2 (hexokinase 2), and LDHA (lactate dehydrogenase) expression and increased pyruvate and lactate production in PDAC patients. Additionally, MIF augments glucose uptake and lactate efflux by upregulating HK1, HK2 and LDHA expression in pancreatic cancer cells in vitro and in mouse models of PDAC. Conversely, a reduction in HK1, HK2, LDHA expression is observed in tumors with high NR3C2 expression in PDAC patients. NR3C2 suppresses HK1, HK2, and LDHA expression, thereby inhibiting glucose uptake and lactate efflux in pancreatic cancer. Mechanistically, MIF-mediated regulation of glycolytic metabolism involves the activation of MAPK-ERK signaling pathway, whereas NR3C2 interacts with the activator protein 1 (AP-1) to regulate glycolysis. Our findings reveal an interactive role of the MIF/NR3C2 axis in regulating glucose metabolism supporting tumor growth and progression and may be a potential target for designing novel approaches for improving disease outcome.

Abstract 6225: SERPINB3 promotes the aggressive basal-like/squamous subtype and correlates with poor prognosis in pancreatic ductal adenocarcinoma through metabolic reprogramming

In this study, we aimed to find genes with a key function in the development of molecular subtypes in pancreatic ductal adenocarcinoma (PDAC). Through transcriptome analysis, we discovered that the endogenous serine/cysteine proteinase inhibitor SERPINB3 (squamous cell carcinoma antigen 1, SCCA1) was distinctively upregulated in the basal-like/squamous subtype, known as an aggressive subtype, and this upregulation associated with decreased patient survival in both a test (N=123) and a validation cohort (N=84). In additional investigations of the tumor metabolome and transcriptome using PDAC patient tumors and cell lines, SERPINB3 and the basal-like/squamous subtype showed a robust relationship with upregulated levels of amino acids (e.g., hydroxyproline) whereas SERPINB3 promoted a gene signature indicative of the basal-like/squamous subtype. Additional mechanistic studies revealed that SERPINB3 and hydroxyproline promoted the migration/invasion of PDAC cells. Moreover, SERPINB3 also promoted metastasis in an orthotopic mouse model of PDAC through stromal factors that increased tumor microvessel density. To conclude, inhibiting SERPINB3 function may attenuate disease progression of the basal-like/squamous subtype in PDAC through changes to the tumor stroma and tumor metabolism.

Citation Format: Yuuki Ohara, Wei Tang, Liu Huaitian, Shouhui Yang, Peijun He, Helen Cawley, Paloma Valenzuela, Lin Zhang, Jochen Gaedcke, B. Michael Ghadimi, Matthias M. Gaida, Frank Bergmann, H. Richard Alexander, Nader Hanna, Stefan Ambs, S. Perwez Hussain. SERPINB3 promotes the aggressive basal-like/squamous subtype and correlates with poor prognosis in pancreatic ductal adenocarcinoma through metabolic reprogramming [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6225.

Dysregulation of HNF1B/Clusterin axis enhances disease progression in a highly aggressive subset of pancreatic cancer patients

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy and is largely refractory to available treatments. Identifying key pathways associated with disease aggressiveness and therapeutic resistance may characterize candidate targets to improve patient outcomes. We used a strategy of examining the tumors from a subset of PDAC patient cohorts with the worst survival to understand the underlying mechanisms of aggressive disease progression and to identify candidate molecular targets with potential therapeutic significance. Non-negative matrix factorization (NMF) clustering, using gene expression profile, revealed three patient subsets. A 142-gene signature specific to the subset with the worst patient survival, predicted prognosis and stratified patients with significantly different survival in the test and validation cohorts. Gene-network and pathway analysis of the 142-gene signature revealed dysregulation of Clusterin (CLU) in the most aggressive patient subset in our patient cohort. Hepatocyte nuclear factor 1 b (HNF1B) positively regulated CLU, and a lower expression of HNF1B and CLU was associated with poor patient survival. Mechanistic and functional analyses revealed that CLU inhibits proliferation, 3D spheroid growth, invasiveness and epithelial-to-mesenchymal transition (EMT) in pancreatic cancer cell lines. Mechanistically, CLU enhanced proteasomal degradation of EMT-regulator, ZEB1. In addition, orthotopic transplant of CLU-expressing pancreatic cancer cells reduced tumor growth in mice. Furthermore, CLU enhanced sensitivity of pancreatic cancer cells representing aggressive patient subset, to the chemotherapeutic drug gemcitabine. Taken together, HNF1B/CLU axis negatively regulates pancreatic cancer progression and may potentially be useful in designing novel strategies to attenuate disease progression in PDAC patients.

Inhibition of Wnt/β-Catenin Signaling Sensitizes Esophageal Cancer Cells to Chemoradiotherapy

The standard treatment of locally advanced esophageal cancer comprises multimodal treatment concepts including preoperative chemoradiotherapy (CRT) followed by radical surgical resection. However, despite intensified treatment approaches, 5-year survival rates are still low. Therefore, new strategies are required to overcome treatment resistance, and to improve patients’ outcome. In this study, we investigated the impact of Wnt/β-catenin signaling on CRT resistance in esophageal cancer cells. Experiments were conducted in adenocarcinoma and squamous cell carcinoma cell lines with varying expression levels of Wnt proteins and Wnt/β-catenin signaling activities. To investigate the effect of Wnt/β-catenin signaling on CRT responsiveness, we genetically or pharmacologically inhibited Wnt/β-catenin signaling. Our experiments revealed that inhibition of Wnt/β-catenin signaling sensitizes cell lines with robust pathway activity to CRT. In conclusion, Wnt/β-catenin activity may guide precision therapies in esophageal carcinoma patients.

Hard wiring of normal tissue-specific chromosome-wide gene expression levels is an additional factor driving cancer type-specific aneuploidies

Background

Many carcinomas have recurrent chromosomal aneuploidies specific to the tissue of tumor origin. The reason for this specificity is not completely understood.

Methods

In this study, we looked at the frequency of chromosomal arm gains and losses in different cancer types from the The Cancer Genome Atlas (TCGA) and compared them to the mean gene expression of each chromosome arm in corresponding normal tissues of origin from the Genotype-Tissue Expression (GTEx) database, in addition to the distribution of tissue-specific oncogenes and tumor suppressors on different chromosome arms.

Results

This analysis revealed a complex picture of factors driving tumor karyotype evolution in which some recurrent chromosomal copy number reflect the chromosome arm-wide gene expression levels of the their normal tissue of tumor origin.

Conclusions

We conclude that the cancer type-specific distribution of chromosomal arm gains and losses is potentially “hardwiring” gene expression levels characteristic of the normal tissue of tumor origin, in addition to broadly modulating the expression of tissue-specific tumor driver genes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00905-y.

NO• /RUNX3/kynurenine metabolic signaling enhances disease aggressiveness in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy and is refractory to available treatments. Delineating the regulatory mechanisms of metabolic reprogramming, a key event in pancreatic cancer progression, may identify candidate targets with potential therapeutic significance. We hypothesized that inflammatory signaling pathways regulate metabolic adaptations in pancreatic cancer. Metabolic profiling of tumors from PDAC patients with a high- (>median, n = 31) and low-NOS2 (inducible nitric oxide synthase; <median, n = 32) mRNA expression was performed. Differentially abundant metabolites were analyzed and linked with patient survival. The functional role of the prognostically significant metabolite and the mechanism of its regulation by NOS2/NO^• (nitric oxide)-mediated signaling pathway was elucidated. The level of kynurenine, a tryptophan metabolite, was associated with high NOS2 expression, and a higher level of kynurenine predicted poor survival in patients (n = 63, p = 0.01). Gene expression analysis in PDAC tumors (n = 63) showed a positive correlation between the expression of NOS2 and the tryptophan/kynurenine pathway genes, including indoleamine-2,3-dioxygenase 1 (IDO1) and several aryl hydrocarbon receptor (AHR)-target genes including NFE2L2 (NRF2), SERPINB2, IL1b, IL6 and IL8, which are implicated in pancreatic cancer. Consistently, treatment of pancreatic cancer cell lines with NO^• donor induced IDO1, kynurenine production and the expression of AHR-target genes. Furthermore, kynurenine treatment enhanced spheroid growth and invasive potential of pancreatic cancer cell lines. Mechanistically, NO^• -induced IDO1/Kynurenine/AHR signaling was mediated by RUNX3 transcription factor. Our findings identified a novel NO^• /RUNX3/Kynurenine metabolic axis, which enhances disease aggressiveness in pancreatic cancer and may have potential translational significance in improving disease outcome.

Epigenome Mapping Identifies Tumor-Specific Gene Expression in Primary Rectal Cancer

Epigenetic alterations play a central role in cancer development and progression. The acetylation of histone 3 at lysine 27 (H3K27ac) specifically marks active genes. While chromatin immunoprecipitation (ChIP) followed by next-generation sequencing (ChIP-seq) analyses are commonly performed in cell lines, only limited data are available from primary tumors. We therefore examined whether cancer-specific alterations in H3K27ac occupancy can be identified in primary rectal cancer. Tissue samples from primary rectal cancer and matched mucosa were obtained. ChIP-seq for H3K27ac was performed and differentially occupied regions were identified. The expression of selected genes displaying differential occupancy between tumor and mucosa were examined in gene expression data from an independent patient cohort. Differential expression of four proteins was further examined by immunohistochemistry. ChIP-seq for H3K27ac in primary rectal cancer and matched mucosa was successfully performed and revealed differential binding on 44 regions. This led to the identification of genes with increased H3K27ac, i.e., RIPK2, FOXQ1, KRT23, and EPHX4, which were also highly upregulated in primary rectal cancer in an independent dataset. The increased expression of these four proteins was confirmed by immunohistochemistry. This study demonstrates the feasibility of ChIP-seq-based epigenome mapping of primary rectal cancer and confirms the value of H3K27ac occupancy to predict gene expression differences.

Enhancer-driven transcriptional regulation is a potential key determinant for human visceral and subcutaneous adipocytes

Obesity is characterized by the excess of body fat leading to impaired health. Abdominal fat is particularly harmful and is associated with cardiovascular and metabolic diseases and cancer. In contrast, subcutaneous fat is generally considered less detrimental. The mechanisms that establish the cellular characteristics of these distinct fat types in humans are not fully understood. Here, we explored whether differences of their gene regulatory mechanisms can be investigated in vitro. For this purpose, we in vitro differentiated human visceral and subcutaneous pre-adipocytes into mature adipocytes and obtained their gene expression profiles and genome-wide H3K4me3, H3K9me3 and H3K27ac patterns. Subsequently, we compared those data with public gene expression data from visceral and subcutaneous fat tissues. We found that the in vitro differentiated adipocytes show significant differences in their transcriptional landscapes, which correlate with biological pathways that are characteristic for visceral and subcutaneous fat tissues, respectively. Unexpectedly, visceral adipocyte enhancers are rich on motifs for transcription factors involved in the Hippo-YAP pathway, cell growth and inflammation, which are not typically associated with adipocyte function. In contrast, enhancers of subcutaneous adipocytes show enrichment of motifs for common adipogenic transcription factors, such as C/EBP, NFI and PPARγ, implicating substantially disparate gene regulatory networks in visceral and subcutaneous adipocytes. Consistent with the role in obesity, predominantly the histone modification pattern of visceral adipocytes is linked to obesity-associated diseases. Thus, this work suggests that the properties of visceral and subcutaneous fat tissues can be studied in vitro and provides preliminary insights into their gene regulatory processes.

Inducible nitric oxide synthase enhances disease aggressiveness in pancreatic cancer

Pancreatic cancer is one of the most lethal malignancies and is refractory to the available treatments. Pancreatic ductal adenocarcinoma (PDAC) expresses high level of inducible nitric oxide synthase (NOS2), which causes sustained production of nitric oxide (NO). We tested the hypothesis that an aberrantly increased NO-release enhances the development and progression of PDAC. Enhanced NOS2 expression in tumors significantly associated with poor survival in PDAC patients (N = 107) with validation in independent cohorts. We then genetically targeted NOS2 in an autochthonous mouse model of PDAC to examine the effect of NOS2-deficiency on disease progression and survival. Genetic ablation of NOS2 significantly prolonged survival and reduced tumor severity in LSL-Kras^G12D/+; LSL-Trp53^R172H/+; Pdx-1-Cre (KPC) mice. Primary tumor cells isolated from NOS2-deficient KPC (NKPC) mice showed decreased proliferation and invasiveness as compared to those from KPC mice. Furthermore, NKPC tumors showed reduced expression of pERK, a diminished inactivation of Forkhead box transcription factor O (FOXO3), a tumor suppressor, and a decrease in the expression of oncomir-21, when compared with tumors in KPC mice. Taken together, these findings showed that NOS2 is a predictor of prognosis in early stage, resected PDAC patients, and provide proof-of-principle that targeting NOS2 may have potential therapeutic value in this lethal malignancy.

Colorectal cancer susceptibility loci as predictive markers of rectal cancer prognosis after surgery

To understand the molecular mechanism of rectal cancer and develop markers for disease prognostication, we generated and explored a dataset from 243 rectal cancer patients by gene expression microarray analysis of cancer samples and matched controls, and SNP-arrays of germline DNA. We found that two of the loci most strongly linked with colorectal cancer (CRC) risk, 8q24 (upstream of MYC) and 18q21 (in the intron of SMAD7), as well as 20q13 (in the intron of LAMA5), are tightly associated with the prognosis of rectal cancer patients. For SNPs on 18q21 (rs12953717 and rs4464148) and 20q13 (rs4925386), alleles that correlate with higher risk for the development of CRC are associated with shorter disease free survival (DFS). However, for rs6983267 on 8q24, the low risk allele is associated with a higher risk for recurrence and metastasis after surgery, and importantly, is strongly correlated with the resistance of CRC cell lines to chemoradiotherapy (CRT). We also found that although MYC expression is dramatically increased in cancer, patients with higher levels of MYC have a better prognosis. The expression of SMAD7 is weakly correlated with DFS. Notably, the presence of the 8q24 and 18q21 SNP alleles is not correlated with expression levels of MYC and SMAD7. rs4464148, and probably rs6983267 and rs4925386, are linked with overall survival time of patients. In conclusion, we show that several CRC risk SNPs detect subpopulations of rectal cancer patients with poor prognosis, and that rs6983267 probably affects prognosis through interfering with the resistance of cancer cells to CRT.

Chemoradiotherapy Resistance in Colorectal Cancer Cells is Mediated by Wnt/β-catenin Signaling

Activation of Wnt/β-catenin signaling plays a central role in the development and progression of colorectal cancer. The Wnt-transcription factor, TCF7L2, is overexpressed in primary rectal cancers that are resistant to chemoradiotherapy and TCF7L2 mediates resistance to chemoradiotherapy. However, it is unclear whether the resistance is mediated by a TCF7L2 inherent mechanism or Wnt/β-catenin signaling in general. Here, inhibition of β-catenin by siRNAs or a small-molecule inhibitor (XAV-939) resulted in sensitization of colorectal cancer cells to chemoradiotherapy. To investigate the potential role of Wnt/β-catenin signaling in controlling therapeutic responsiveness, nontumorigenic RPE-1 cells were stimulated with Wnt-3a, a physiologic ligand of Frizzled receptors, which increased resistance to chemoradiotherapy. This effect could be recapitulated by overexpression of a degradation-resistant mutant of β-catenin (S33Y), also boosting resistance of RPE-1 cells to chemoradiotherapy, which was, conversely, abrogated by siRNA-mediated silencing of β-catenin. Consistent with these findings, higher expression levels of active β-catenin were observed as well as increased TCF/LEF reporter activity in SW1463 cells that evolved radiation resistance due to repeated radiation treatment. Global gene expression profiling identified several altered pathways, including PPAR signaling and other metabolic pathways, associated with cellular response to radiation. In summary, aberrant activation of Wnt/β-catenin signaling not only regulates the development and progression of colorectal cancer, but also mediates resistance of rectal cancers to chemoradiotherapy.Implications: Targeting Wnt/β-catenin signaling or one of the downstream pathways represents a promising strategy to increase response to chemoradiotherapy. Mol Cancer Res; 15(11); 1481-90. ©2017 AACR.

Abstract 4789: A novel MIF signaling pathway drives the malignant character of pancreatic cancer by targeting NR3C2

Pancreatic cancers with aberrant expression of macrophage migration inhibitory factor (MIF) are particularly aggressive. To identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression, we analyzed the expression of coding and noncoding genes in high and low MIF-expressing tumors in multiple cohorts of pancreatic ductal adenocarcinoma (PDAC) patients. The key genes and pathways identified were linked to patient survival and were mechanistically, functionally, and clinically characterized using cell lines, a genetically engineered mouse model, and PDAC patient cohorts. Here, we report evidence of a novel MIF-driven signaling pathway that inhibits the orphan nuclear receptor NR3C2, a previously undescribed tumor suppressor that impacts aggressiveness and survival in PDAC. Mechanistically, MIF upregulated miR-301b that targeted NR3C2 and suppressed its expression. PDAC tumors expressing high levels of MIF displayed elevated levels of miR-301b and reduced levels of NR3C2. In addition, reduced levels of NR3C2 expression correlated with poorer survival in multiple independent cohorts of PDAC patients. Functional analysis showed that NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to the gemcitabine, a chemotherapeutic drug used in PDAC standard of care. Furthermore, genetic deletion of MIF disrupted a MIF-mir-301b-NR3C2 signaling axis, reducing metastasis and prolonging survival in a genetically engineered mouse model of PDAC. Taken together, our results offer a preclinical proof of principle for candidate therapies to target a newly described MIF-miR-301b-NR3C2 signaling axis for PDAC management.

Citation Format: Shouhui Yang, Peijun He, Liming Wang, Jian Wang, Aaron Schetter, Wei Tang, Naotake Funamizu, Katsuhiko Yanaga, Tadashi Uwagawa, Abhay R. Satoskar, Jochen Gaedcke, Markus Bernhardt, B. Michael Ghadimi, Matthias M Gaida, Frank Bergmann, Jens Werner, Thomas Ried, Nader Hanna, H. Richard Alexander, S. Perwez Hussain. A novel MIF signaling pathway drives the malignant character of pancreatic cancer by targeting NR3C2 [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 4789. doi:10.1158/1538-7445.AM2017-4789

The Prognostic Value of Tyrosine Kinase SRC Expression in Locally Advanced Rectal Cancer

The cellular sarcoma gene (SRC) is a proto-oncogene encoding for a tyrosine kinase. SRC expression was determined in locally advanced rectal adenocarcinoma tissue from pretreatment biopsies and resection specimens. The expression level was correlated with clinicopathological parameters to evaluate the predictive and prognostic capacity.

For this monocentric analysis 186 patients with locally advanced rectal cancer (median: 63.7 years; 130 men (69.9%), 56 women (30.1%)) were included. Patients with a carcinoma of the upper third of the rectum were treated with primary tumor resection (n=27; 14.5%). All other patients received a preoperative chemoradiotherapy (CRT) with 50.4 Gy and concomitant 5-fluorouracil (5-FU) or 5-FU+oxaliplatin followed by postoperative chemotherapy with 5-FU or 5-FU+oxaliplatin. SRC expression was determined with immunohistochemical staining from pretreatment biopsies (n=152) and residual tumor tissue from the resection specimens (n=163). The results were correlated with clinicopathological parameters and long-term follow-up.

The expression of SRC was determined in pretherapeutic biopsies (mean H-Score: 229) and resection specimens (mean H-Score: 254). High SRC expression in pretherapeutic tumor samples significantly correlated with a negative postoperative nodal status (p=0.005). Furthermore an increased protein expression in residual tumor tissue was associated with fewer distant metastases (p=0.04). The overexpression of SRC in pretreatment tumor biopsies showed also a trend for a longer cancer-specific survival (CSS; p=0.05) and fewer local relapses (p=0.06) during long-term follow-up.

High SRC expression in rectal cancer seems to be associated with a better long-term outcome. This finding could help in the future to stratify patients for a recurrence risk adapted postoperative treatment.

Endothelial Nitric Oxide Synthase Traffic Inducer (NOSTRIN) is a Negative Regulator of Disease Aggressiveness in Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is refractory to available treatments. Delineating critical pathways, responsible for disease aggressiveness and therapeutic resistance, may identify effective therapeutic targets. We aimed to identify key pathways contributing to disease aggressiveness by comparing gene expression profiles of tumors from early-stage PDAC cases with extremely poor survival (≤7 months) and those surviving 2 years or more following surgical resection.

EXPERIMENTAL DESIGN

Gene expression profiling was performed in tumors in a test cohort of PDAC (N = 50), which included short (≤7 months, N = 11) and long surviving (≥2 years, N = 14) patients, using affymetrix GeneChip Human 1.0 ST array. Key genes associated with disease aggressiveness were identified, using Cox regression, Kaplan-Meier, and pathway analyses with validations in independent cohorts for mechanistic and functional analyses.

RESULTS

Gene expression profiling identified 1,820 differentially expressed genes between short and long survival groups with inflammatory gene network ranking first. Lower expression of endothelial nitric oxide synthase traffic inducer (NOSTRIN) was associated with worst survival indicating its potential inhibitory role in disease progression. NOSTRIN overexpression suppressed migration and invasion of pancreatic cancer cells and enhanced sensitivity to chemotherapeutic drug gemcitabine. NOSTRIN inhibited production of nitric oxide (NO) by suppressing the activation of endothelial nitric oxide synthase (eNOS). Furthermore, miR-221, bound to the 3'UTR of NOSTRIN and suppressed its expression, and an increased miR-221 expression associated with poor survival in PDAC.

CONCLUSIONS

Our findings showed that NOSTRIN is a potential negative regulator of disease aggressiveness, which may be targeted for designing improved treatment strategy in PDAC. Clin Cancer Res; 22(24); 5992-6001. ©2016 AACR.

Abstract B34: A Novel MIF-driven Signaling Drives Disease Aggressiveness by Targeting NR3C2 in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy. Pancreatic tumors with aberrant expression of macrophage migration inhibitory factor (MIF) are highly aggressive, and an increased MIF predicts poorer patient survival. We analyzed the expression of coding and non-coding genes in high and low MIF-expressing tumors in multiple cohorts of PDAC patients to identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression. The identified key genes and pathways were linked to patients’ survival and were mechanistically, functionally and clinically characterized using cell lines, genetically engineered mouse model and PDAC patient cohorts. Here, we report mechanistic, functional and clinical evidence of a novel MIF-driven signaling pathway that inhibits a previously undescribed tumor suppressor, nuclear-receptor-subfamily-3, group-C, member-2 (NR3C2), leading to enhanced disease aggressiveness and poorer survival in PDAC. MIF upregulated miR-301b, which then targeted and suppressed NR3C2 expression. Tumors with high MIF expression showed an elevated miR-301b and a reduced NR3C2 expression. Additionally, patients with a lower NR3C2 expression in tumors showed poorer survival in multiple independent cohorts of PDAC patients. NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to chemotherapeutic drug gemcitabine. Furthermore, genetic deletion of MIF disrupted MIF-mir-301b-NR3C2 axis, which resulted in reduced metastasis and prolonged survival in genetically engineered mouse model of PDAC. These findings provide proof-of-principle that therapies targeting MIF-miR-301b-NR3C2 axis may improve disease outcome in PDAC

Citation Format: Shouhui Yang, Peijun He, Jian Wang, Aaron Schetter, Wei Tang, Naotake Funamizu, Katsuhiko Yanaga, Tadashi Uwagawa, Abhay R. Satoskar, Jochen Gaedcke, Markus Bernhardt, B. Michael Ghadimi, Matthias M. Gaida, Frank Bergmann, Jens Werner, Thomas Ried, Nader Hanna, H. Richard Alexander, S. Perwez Hussain.{Authors}. A Novel MIF-driven Signaling Drives Disease Aggressiveness by Targeting NR3C2 in Pancreatic Cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B34.

Cancer Gene Profiling for Response Prediction

The revolution of genomic technologies, including gene expression profiling, high-resolution mapping of genomic imbalances, and next-generation sequencing, allows us to establish molecular portraits of cancer cells with unprecedented accuracy. This generates hope and justifies anticipation that disease diagnosis, prognosis, and the choice of treatment will be adapted to the individual needs of patients based on molecular evidence. Preoperative treatment strategies are now recommended for a variety of human cancers. Unfortunately, the response of individual tumors to a preoperative treatment is not uniform, and ranges from complete regression to resistance. This poses a considerable clinical dilemma, as patients with a priori resistant tumors could either be spared exposure to radiation or DNA-damaging drugs, i.e., could be referred to primary surgery, or dose-intensified protocols could be pursued. Because the response of an individual tumor as well as therapy-induced side effects represent the major limiting factors of current treatment strategies, identifying molecular markers of response or for treatment toxicity has become exceedingly important. However, complex phenotypes such as tumor responsiveness to multimodal treatments probably do not depend on the expression levels of just one or a few genes and proteins. Therefore, methods that allow comprehensive interrogation of genetic pathways and networks hold great promise in delivering such tumor-specific signatures, since expression levels of thousands of genes can be monitored simultaneously. Over the past few years, microarray technology has emerged as a central tool in addressing pertinent clinical questions, the answers to which are critical for the realization of a personalized genomic medicine, in which patients will be treated based on the biology of their tumor and their genetic profile (Quackenbush, N Engl J Med 354:2463-72, 2006; Jensen et al., Curr Opin Oncol 18:374-380, 2006; Bol and Ebner, Pharmacogenomics 7:227-235, 2006; Nevins and Potti, Nat Rev Genet 8:601-609, 2007).

[Management of delayed complications after esophagectomy]

Esophagectomy and subsequent reconstruction represent major physiological insults to the upper gastrointestinal (GI) tract, which as a consequence can lead to malnutrition, dysphagia and reflux. From a technical perspective, operative reconstruction involving gastric pull-up with a 2-3 cm wide tube and an anastomosis cranial to the azygos vein may minimize the symptoms. Overall, the problems tend to improve approximately 6 months after the operation. Newly occurring delayed physical functional impairments with previously known underlying malignant disease may be indicative of cancer relapse. Interventional techniques, such as stent placement or brachytherapy may be better suited for treatment of recurrent disease.

MicroRNA in rectal cancer

In rectal cancer, one of the most common cancers worldwide, the proper staging of the disease determines the subsequent therapy. For those with locally advanced rectal cancer, a neoadjuvant chemoradiotherapy (CRT) is recommended before any surgery. However, response to CRT ranges from complete response (responders) to complete resistance (non-responders). To date we are not able to separate in advance the first group from the second, due to the absence of a valid biomarker. Therefore all patients receive the same therapy regardless of whether they reap benefits. On the other hand almost all patients receive a surgical resection after the CRT, although a watch-and-wait procedure or an endoscopic resection might be sufficient for those who responded well to the CRT. Being highly conserved regulators of gene expression, microRNAs (miRNAs) seem to be promising candidates for biomarkers. Many studies have been analyzing the miRNAs expressed in rectal cancer tissue to determine a specific miRNA profile for the ailment. Unfortunately, there is only a small overlap of identified miRNAs between different studies, posing the question as to whether different methods or differences in tissue storage may contribute to that fact or if the results simply are not reproducible, due to unknown factors with undetected influences on miRNA expression. Other studies sought to find miRNAs which correlate to clinical parameters (tumor grade, nodal stage, metastasis, survival) and therapy response. Although several miRNAs seem to have an impact on the response to CRT or might predict nodal stage, there is still only little overlap between different studies. We here aimed to summarize the current literature on rectal cancer and miRNA expression with respect to the different relevant clinical parameters.

HER-2 and HER-3 expression in liver metastases of patients with colorectal cancer

OBJECTIVE

In this study, we evaluate the frequency of HER-2 and HER-3 expression in liver metastases from patients with colorectal cancer (CRLM). We analyzed the potential of HER-2 and HER-3 as therapeutic targets and evaluated their prognostic value.

PATIENTS AND METHODS

Overall 208 patients with CRLM were enrolled. HER-2 and HER-3 expression were determined in metastatic tissue of diagnostic punch biopsies (n = 29) or resection specimens (n = 179). The results of immunohistochemistry (IHC) scoring and In-situ-hybridization (ISH)-amplification were correlated with clinical parameters and for the 179 resected patients with cancer-specific (CSS) and overall survival (OS). The mean follow-up time was 56.7 months.

RESULTS

Positivity of HER-2 status (IHC score 2+/ISH+ and IHC 3+) was found in 8.2% of CRLM. High expression of HER-3 (IHC score 2+ and IHC 3+) was detected in 75.0% of liver metastases. CSS after liver surgery was determined and was independent from the HER-2 status (p = 0.963); however HER-3 was prognostic with a favorable course for patients showing an overexpression of HER-3 (p = 0.037).

CONCLUSIONS

HER-2 overexpression occurs in only 8% of patients with CRLM but with 75% of cases HER-3 is frequently overexpressed in CRLM. Therefore, HER-2 and particularly HER-3 could serve as novel targets to be addressed within multimodal treatment approaches.

A Novel MIF Signaling Pathway Drives the Malignant Character of Pancreatic Cancer by Targeting NR3C2

Pancreatic cancers with aberrant expression of macrophage migration inhibitory factor (MIF) are particularly aggressive. To identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression, we analyzed the expression of coding and noncoding genes in high and low MIF-expressing tumors in multiple cohorts of pancreatic ductal adenocarcinoma (PDAC) patients. The key genes and pathways identified were linked to patient survival and were mechanistically, functionally, and clinically characterized using cell lines, a genetically engineered mouse model, and PDAC patient cohorts. Here, we report evidence of a novel MIF-driven signaling pathway that inhibits the orphan nuclear receptor NR3C2, a previously undescribed tumor suppressor that impacts aggressiveness and survival in PDAC. Mechanistically, MIF upregulated miR-301b that targeted NR3C2 and suppressed its expression. PDAC tumors expressing high levels of MIF displayed elevated levels of miR-301b and reduced levels of NR3C2. In addition, reduced levels of NR3C2 expression correlated with poorer survival in multiple independent cohorts of PDAC patients. Functional analysis showed that NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to the gemcitabine, a chemotherapeutic drug used in PDAC standard of care. Furthermore, genetic deletion of MIF disrupted a MIF-mir-301b-NR3C2 signaling axis, reducing metastasis and prolonging survival in a genetically engineered mouse model of PDAC. Taken together, our results offer a preclinical proof of principle for candidate therapies to target a newly described MIF-miR-301b-NR3C2 signaling axis for PDAC management. Cancer Res; 76(13); 3838-50. ©2016 AACR.

Prognostic Value of MicroRNAs in Preoperative Treated Rectal Cancer

Background: Patients with locally advanced rectal cancer are treated with preoperative chemoradiotherapy followed by surgical resection. Despite similar clinical parameters (uT2-3, uN+) and standard therapy, patients’ prognoses differ widely. A possible prediction of prognosis through microRNAs as biomarkers out of treatment-naïve biopsies would allow individualized therapy options. Methods: Microarray analysis of 45 microdissected preoperative biopsies from patients with rectal cancer was performed to identify potential microRNAs to predict overall survival, disease-free survival, cancer-specific survival, distant-metastasis-free survival, tumor regression grade, or nodal stage. Quantitative real-time polymerase chain reaction (qPCR) was performed on an independent set of 147 rectal cancer patients to validate relevant miRNAs. Results: In the microarray screen, 14 microRNAs were significantly correlated to overall survival. Five microRNAs were included from previous work. Finally, 19 miRNAs were evaluated by qPCR. miR-515-5p, miR-573, miR-579 and miR-802 demonstrated significant correlation with overall survival and cancer-specific survival (p < 0.05). miR-573 was also significantly correlated with the tumor regression grade after preoperative chemoradiotherapy. miR-133b showed a significant correlation with distant-metastasis-free survival. miR-146b expression levels showed a significant correlation with nodal stage. Conclusion: Specific microRNAs can be used as biomarkers to predict prognosis of patients with rectal cancer and possibly stratify patients’ therapy if validated in a prospective study.

[Robotic Rectal Cancer Surgery]

BACKGROUND

The oncological outcome of patients with rectal cancer has improved considerably over the past few decades. This is mainly due to the introduction of the surgical concept of total mesorectal excision (TME) and the implementation of multimodal treatment strategies. Additionally, it has recently been demonstrated that the oncological results of open and laparoscopic TME are comparable. For some time there has been an ongoing debate on the potential relevance of robotic assistance systems in visceral surgery. The aim of this study was to evaluate the operative and perioperative outcomes of patients with rectal or rectosigmoid cancer, who were operated on using the Da Vinci Surgical System.

PATIENTS AND RESULTS

We retrospectively analysed the outcomes of 202 consecutive patients, who were operated between September 2010 and November 2015 in three Surgical Centers. The cohort consisted of 136 men and 66 women with a mean BMI of 28. We performed the following procedures: 49 anterior rectal resections, 119 low anterior rectal resections, and 34 abdominoperineal excisions. Conversion to an open procedure was required in 13 patients. Non-surgical complications (n = 27) occurred in 24 patients (12%) and surgical complications (n = 67) in 62 patients (31%). Most complications were due to abdominal or sacral wound infections (n = 25) and anastomotic leaks (n = 18). The mortality rate within 30 days was 2%. The rate of R0 resections was 95%, with circumferential resection margins being negative in 98% of the patients. The quality of the mesorectal resection was scored as good in 91% of the patients.

CONCLUSIONS

The Da Vinci Surgical System can be used safely and with a low complication rate for surgical treatment of rectal cancer. While primary evidence suggests that the outcome of robotic-assisted surgery is comparable with open and laparoscopic surgery, its definitive value has to be determined upon publication of the prospective randomized ROLARR trial. The main advantages of the Da Vinci system are its endowristed instruments with multiple degrees of freedom and its optimised visualisation (3D, stable camera platform controlled by the surgeon). Another positive feature is the significant ergonomic advantage for the surgeon.

Relevance of Sp Binding Site Polymorphism in WWOX for Treatment Outcome in Pancreatic Cancer

Background:

A genome-wide association study (GWAS) suggested inherited genetic single-nucleotide polymorphisms (SNPs) affecting overall survival (OS) in advanced pancreatic cancer. To identify robust clinical biomarkers, we tested the strongest reported candidate loci in an independent patient cohort, assessed cellular drug sensitivity, and evaluated molecular effects.

Methods:

This study comprised 381 patients with histologically verified pancreatic ductal adenocarcinoma treated with gemcitabine-based chemotherapy. The primary outcome was the relationship between germline polymorphisms and OS. Functional assays addressed pharmacological dose-response effects in lymphoblastoid cell lines (LCLs) and pancreatic cancer cell lines (including upon RNAi), gene expression analyses, and allele-specific transcription factor binding. All statistical tests were two-sided.

Results:

The A allele (26% in Caucasians) at SNP rs11644322 in the putative tumor suppressor gene WWOX conferred worse prognosis. Median OS was 14 months (95% confidence interval [CI] = 12 to 15 months), 13 months (95% CI = 11 to 15 months), and nine months (95% CI = 7 to 12 months) for the GG, GA, and AA genotypes, respectively (P_trend < .001 for trend in univariate log-rank assuming a codominant mode of inheritance; advanced disease subgroup P_trend < .001). Mean OS was 25 months (95% CI = 21 to 29 months), 19 months (95% CI = 15 to 22 months), and 13 months (95% CI = 10 to 16 months), respectively. This effect held true after adjustment for age, performance status according to Eastern Cooperative Oncology Group classification, TNM, grading, and resection status and was comparable with the strongest established prognostic factors in multivariable analysis. Consistently, reduced responsiveness to gemcitabine, but not 5-fluorouracil, along with lower WWOX expression was demonstrated in LCLs harboring the AA genotype. Likewise, RNAi-mediated WWOX knockdown in pancreatic cancer cells confirmed differential cytostatic drug sensitivity. In electrophoretic mobility shift assays, the A allele exhibited weaker binding of Sp family members Sp1/Sp3.

Conclusions:

WWOX rs11644322 represents a major predictive factor in gemcitabine-treated pancreatic cancer. Decreased WWOX expression may interfere with gemcitabine sensitivity, and allele-specific binding at rs11644332 might be a causative molecular mechanism behind the observed clinical associations.

Hepatocellular carcinoma: Surgeon's view on latest findings and future perspectives

Hepatocellular carcinoma (HCC) is the most common liver-derived malignancy with a high fatality rate. Risk factors for the development of HCC have been identified and are clearly described. However, due to the lack of tumor-specific symptoms, HCC are diagnosed at progressed tumor stages in most patients, and thus curative therapeutic options are limited. The focus of this review is on surgical therapeutic options which can be offered to patients with HCC with special regard to recent findings, not exclusively focused on surgical therapy, but also to other treatment modalities. Further, potential promising future perspectives for the treatment of HCC are discussed.

Comprehensive lymph node morphometry in rectal cancer using acetone compression

Aims

Acetone compression (AC) is an elution compression technique for the comprehensive pathological examination of fatty tissue. Here AC is combined with digital morphometry to evaluate the impact of preoperative (neoadjuvant) chemoradiotherapy (neoCRT) on lymph node (LN) numbers and morphology in locally advanced rectal cancer. AC is compared with complete embedding of the mesorectal fat (whole mesorectal embedding (WME)) to exclude artificial alterations and to the standard technique, manual dissectioning (MD).

Methods

320 rectal cancer specimens were subjected to LN morphometry. Neoadjuvant CRT was applied in 204 specimens. LNs were prepared either with AC (n=138), WME (n=51) or MD (n=131). 8523 LNs were assessed including 530 nodes with metastases.

Results

LN prepared by AC and WME showed similar morphologies. AC revealed reduced LN sizes in neoCRT specimens compared with primary resection (2.2; 2.4 mm, p=0.049) while the LN number was comparable (27; 30/specimen). AC yielded 28 LN/specimen on average, MD yielded 22 LN (p<0.001). In neoCRT specimens, MD yielded less LN compared with primary resection (19; 25). MD detected less small LN (<2 mm; MD: 25%; AC: 56%) while 24 of the 135 LN metastases found by AC were ≤2 mm in diameter.

Conclusions

AC does not alter LN morphology and is especially suited to retrieve small LN after neoadjuvant CRT of rectal cancer. Neoadjuvant multimodality treatment caused reduced LN sizes while the LN numbers were not affected. When compared with MD, AC proved more reliable in the retrieval of LN from rectal cancer specimens after neoCRT.

Repeated anti-CEA-radioimmunotherapy (RAIT) with 131iodine-labetuzumab after resection of colorectal liver metastases (CLM): Long-term results of a prospective phase II study

719

Background: Previously, single anti-CEA-radioimmunotherapy (RAIT) with 131iodine(I)-labetuzumab after complete (R0) resection of CEA-positive CLM was well tolerated and improved overall survival (OS) compared to a control group without RAIT. In this phase II study, we examined safety, feasibility, and long-term efficacy of repeated RAIT in the same setting. Methods: After R0-resection of CEA-positive CLM, 63 pts (42 m, 21 f; median age, 64.5 yrs) with synchronous (n=33) or metachronous (n=30) CLM received RAIT with 40-50 mCi/m2 per dose. 45 pts were intermediate/high risk for early metastatic relapse according to the Fong score. Restaging with CT/MRI and FDG-PET was performed prior to each RAIT. Pts with persistent elevated serum CEA-levels or inconclusive lesions during post-operative restaging received RAIT, but were classified as “non-adjuvant.” Toxicity was classified according to NCI-CTC v2.0. Time to progression (TTP), OS and cancer-specific survival (CSS) were calculated. The median follow-up was 54 (range 6-127) mos. Results: After the first cycle of RAIT 14 of 63 pts experienced grade 4 hematological toxicity. Nineteen pts did not receive the second cycle of RAIT due to prolonged toxicity, impaired performance status (n=6), or metastatic relapse (n=13). The latter were further treated by resection (n=3) or systemic chemotherapy (n=10). Forty-four pts received the planned second cycle of RAIT. Of these, 4 pts newly experienced grade 4 hematological toxicity. For all 63 pts, the median TTP, OS and CSS were 13, 57 and 92 months, respectively. The truly “adjuvant” pts (n=39) had a an improved median TTP (26 vs. 6.6 mos, p<0.0001), OS (76 vs. 42 mos, p=0.03) and CSS (not reached vs. 42 mos, p=0.003) in comparison to “non-adjuvant” pts (n=24). Conclusions: Repeated anti-CEA-RAIT with 131I-labetuzumab is safe, feasible, and well-tolerated (100% compliance), with expected hematological toxicity. The long-term survival after RAIT is very encouraging, in particular for pts deemed truly “adjuvant” post-salvage resection of CLM at restaging prior to RAIT.

Abstract 4363: Macrophage migration inhibitory factor (MIF) and miR-301b interactively enhance disease aggressiveness by targeting NR3C2 in human pancreatic cancer

MIF is a pleiotropic cytokine, which plays a role in inflammatory and immune responses and is implicated in tumorigenesis. Our previous study showed that MIF enhances tumor aggressiveness and predicts outcome in patients with pancreatic ductal adenocarcinoma (PDAC). Aberrant microRNA (miRNA) expression is a common feature in cancer and cytokine responsive miRNAs are recently described as critical effectors in tumor progression. We have investigated MIF-associated miRNAs and their interactive roles in the progression of human pancreatic cancer. Global analysis of miRNA expression revealed 38 differentially expressed miRNAs in MIF-high as compared with MIF-low cases of PDAC based on the median value. Kaplan-Meier survival analysis showed that a higher expression of miR-301b in tumors was associated with poorer survival (p=0.008, N=37), which was further validated in an independent cohort of PDAC patients (p=0.021, N=42). Additionally, MIF expression positively correlated with miR-301b and mediated its expression in several human pancreatic cancer cells. Mechanistic analysis revealed that miR-301b promotes pancreatic cancer cell migration and invasion. Furthermore, nuclear receptor subfamily group c member 2 (NR3C2) was identified as a functional target of miR-301b. NR3C2 inhibited tumor migration and invasion and a higher expression of NR3C2 predicted better survival in pancreatic cancer patients. Further in vivo studies showed a significant decrease in NR3C2 in MIF-overexpressing orthotopic xenograft as compared to control. Taken together, our results demonstrate that MIF and miR-301b interactively contribute to pancreatic cancer progression by targeting NR3C2. This novel MIF-miR-301b-NR3C2 axis may provide potential targets for improving disease outcome in pancreatic cancer.

Citation Format: Shouhui Yang, Peijun He, Jian Wang, Aaron Schetter, Naotake Funamizu, Katsuhiko Yanaga, Jochen Gaedcke, B. Michael Ghadimi, Matthias M. Gaida, Thomas Ried, Nader Hanna, H. Richard Alexander, S. Perwez Hussain. Macrophage migration inhibitory factor (MIF) and miR-301b interactively enhance disease aggressiveness by targeting NR3C2 in human pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4363. doi:10.1158/1538-7445.AM2014-4363

Abstract 855: Targeting STAT3 in vitro and in vivo reveals a novel therapeutic strategy to sensitize colorectal cancer cells to chemoradiotherapy

Introductory sentence:

Increased activity of signal transducer and activator of transcription 3 (STAT3) is common in human malignancies, including colorectal cancers. Recently, we reported that STAT3 expression correlated with resistance to 5-fluorouracil (5-FU) based chemoradiotherapy. This is of considerable clinical relevance, because a large proportion of rectal cancers are resistant to preoperative multimodal treatment. We therefore examined whether STAT3 contributes to resistance to chemoradiotherapy.

Experimental procedures:

STAT3 mRNA and protein expression levels were determined in 12 colorectal cancers cell lines. STAT3 was inhibited using two different siRNAs and a small-molecular inhibitor (STATTIC) in the cell lines SW480 and SW837. Successful RNAi-mediated silencing of STAT3 or inhibition of phosphoSTAT3(Tyr705) was detected by Western blot and reduction of transcription factor activity was measured by a luciferase reporter assay. Additionally, we established doxycycline-inducible stable shRNA single cell populations and a non-silencing shRNA (shNEG) in SW480. To test the influence of STAT3 knock down or inhibition, clonogenic survival assays were performed. Therefore, RNAi or inhibitor treated cells were exposed to chemoradiotherapy using 3µM 5-FU and X-ray-irradiation at 1, 2, 4, 6, and 8 Gy. Finally, we tested the effect of a chemoradiotherapy combined with STATTIC treatment in a SW837 xenograft model in NMRI nude mice. To verify the sensitizing effect of STATTIC, tumor growth was recorded and growth delay assays were performed.

Data:

STAT3 was overexpressed in resistant cells at mRNA and protein level. siRNA transfected SW480, SW837, and SW480shRNA single cell clones showed a significant reduction of STAT3 protein and transcription factor activity after 96 hours. STATTIC inhibition led to a decreased phosphorylation of STAT3 after 1 hour. The silencing/inhibition resulted in a significantly increased chemoradiosensitivity with dose-reduction factors of 1.3 to 2.5 at a surviving fraction of 0.37. In vivo, additional STAT3 inhibition during chemoradiotherapy led to a profound chemoradiosensitization effect and a significant tumor growth delay in STATTIC treated mice. Survival of these mice was also enhanced, if compared to the control group.

Conclusions:

STAT3 is highly overexpressed in resistant colorectal cancer cells, and silencing or inhibition of STAT3 leads to a significantly increased chemoradiosensitivity in vitro and in vivo. This highlights the potential relevance of STAT3 for mediating treatment resistance and provides a first proof of concept that STAT3 represents a novel molecular target in rectal cancer to sensitize a priori resistant colorectal tumor cells to chemoradiotherapy.

Citation Format: Melanie Spitzner, Birte Roesler, Christian Bielfeld, Carolin Herzberg, Georg Emons, Jochen Gaedcke, Margret Rave-Fränk, Tim Beißbarth, Thomas Ried, B. Michael Ghadimi, Marian Grade. Targeting STAT3 in vitro and in vivo reveals a novel therapeutic strategy to sensitize colorectal cancer cells to chemoradiotherapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 855. doi:10.1158/1538-7445.AM2014-855

STAT3: A Novel Molecular Mediator of Resistance to Chemoradiotherapy

Chemoradiotherapy (CRT) represents a standard treatment for many human cancers, frequently combined with radical surgical resection. However, a considerable percentage of primary cancers are at least partially resistant to CRT, which represents a substantial clinical problem, because it exposes cancer patients to the potential side effects of both irradiation and chemotherapy. It is therefore exceedingly important to determine the molecular characteristics underlying CRT-resistance and to identify novel molecular targets that can be manipulated to re-sensitize resistant tumors to CRT. In this review, we highlight much of the recent evidence suggesting that the signal transducer and activator of transcription 3 (STAT3) plays a prominent role in mediating CRT-resistance, and we outline why inhibition of STAT3 holds great promise for future multimodal treatment concepts in oncology.

Residual rectal cancer after preoperative radiochemotherapy (ypT1-2): An indication for local excision instead of radical surgery?

546

Background: Preoperative radiochemotherapy (RCT) followed by total mesorectal excision (TME) has improved local tumor control and led to a significant tumor downstaging. For patients with pathologic complete response (ypT0) as well as residual tumor restricted only to the bowel wall (ypT1-2) local excision has increasingly been discussed to avoid significant morbidity and functional deficits associated with TME. Therefore we investigated the incidence, distribution and tumor-related localization of mesorectal lymph node (LN) metastases in TME specimens with ypT0, ypT1-2 and ypT3-4 rectal cancers, respectively. Methods: TME specimens from 81 patients with locally advanced rectal cancer treated with neoadjuvant RCT within the phase III German Rectal Cancer Trial CAO/ARO/AIO-04 were evaluated. The entire mesorectal compartment was screened microscopically after complete paraffin embedding. The number and localization of all detectable LN metastases was specified in relation to the primary tumor. Results: Whereas 50 patients (62%) had ypT3-4 carcinomas after neoadjuvant RCT 20 patients (25%) presented with residual tumor within the bowel wall (ypT1-2). 11 patients (14%) had pathologic complete response (ypT0). 28 ± 13.7 LN were detected per specimen. 25 patients (31%) had residual LN metastases after RCT. Although the incidence was higher in the ypT3-4 group (40% ypN+) still 25% of patients in the ypT1-2 group had a mean number of 2.2 residual LN metastases. 55% of these metastases were located afar from the primary lesion in the proximal mesorectum. No patient with ypT0 status had residual LN metastases. Conclusions: Even in patients with good response and tumors restricted only to the bowel wall (ypT1-2) after RCT there is a considerable risk for residual LN metastases. The majority of metastases were located clearly outside the tumor region. Local excision of residual rectal cancer would be accompanied by a higher rate of local failure and radical surgery with TME should remain the standard treatment in those patients.

HER2 and HER3 expression in hepatic metastases of colorectal cancer: New targets for specific treatment approaches?

567

Background: Even though treatment options for coloretal cancer liver metastases have improved with the implementation of multimodal strategies and new agents, progression of distant metastases is still limiting the prognosis of affected patients. In this context we investigated the expression of HER2 and HER3 in patients with metastatic colorectal cancer and primary tumors. Methods: In this study 226 consecutive patients with hepatic metastases of colorectal cancer were included. HER2 and HER3 expression were determined in the tissue from resected metastases and—if available—in primary tumors. Immunohistochemical scoring (IHC 0 to IHC 3) and S-ISH-amplification-detection (for HER2) were used to determine the HER2 and HER3 status. Results: A positive HER2 status was found in 8.4% of all hepatic metastases; an overexpression of HER-3 in 74,8% of all cases. There was a high congruence of the expression pattern of HER2 and HER3 between hepatic metastases and available primary tumors (>90%). Conclusions: HER2 amplification and HER3 overexpression is detectable in a significant proportion of hepatic metastases of colorectal cancer. These results suggest that innovative new targeted treatment agents might be possible opportunities for the specific therapy of patients with HER2/HER3 positive metastatic colorectal cancer and should be further assessed within prospective clinical trials.

Oxaliplatin-Induced Leukocytoclastic Vasculitis under Adjuvant Chemotherapy for Colorectal Cancer: Two Cases of a Rare Adverse Event

Leukocytoclastic vasculitis is a multicausal systemic inflammatory disease of the small vessels, histologically characterized by inflammation and deposition of both nuclear debris and fibrin in dermal postcapillary venules. The clinical picture typically involves palpable purpura of the lower legs and may be associated with general symptoms such as fatigue, arthralgia and fever. Involvement of the internal organs, most notably the kidneys, the central nervous system or the eyes, is possible and determines the prognosis. Oxaliplatin-induced leukocytoclastic vasculitis is a very rare event that limits treatment options in affected patients. We report 2 patients who developed the condition under chemotherapy for advanced rectal and metastatic colon carcinoma, respectively; a termination of the therapy was therefore necessary. While current therapies for colorectal cancer include the combination of multimodal treatment with new and targeted agents, rare and unusual side effects elicited by established agents also need to be taken into account for the clinical management.

Chromosomal aberrations in primary PDGFRA-mutated gastrointestinal stromal tumors

Approximately 15% of gastrointestinal stromal tumors (GISTs) harbor mutations in the platelet-derived growth factor receptor α (PDGFRA) gene. Chromosomal aberrations play a crucial role in tumor progression and correlate with clinical behavior. Imbalances, particularly in PDGFRA-mutated GISTs, have not yet been evaluated in larger series. We analyzed 53 PDGFRA-mutated GISTs (including 2 with corresponding metastases) for chromosomal imbalances by conventional comparative genomic hybridization and compared them with a historical collective of 122 KIT-mutated GISTs. PDGFRA exon 18 mutations (91% of cases) and exon 12 mutations (9% of cases) correlated significantly with gastric and intestinal sites, respectively. The most common aberrations were identical to those found in KIT-mutated GISTs, with -14q in 70%, -1p in 28%, and -22q in 17% of cases. Overall, there were significantly fewer chromosomal aberrations compared with KIT-mutated GISTs, with a mean of 2.8 (0.6 gains, 2.1 losses) aberrations per tumor. There was a statistically significant association of more than 5 chromosomal imbalances with intermediate/high-risk categories. Regarding specific chromosomal aberrations, -9p, -13q, and -22q correlated with intermediate/high risk, and -1p and +8q with poorer survival, although progression occurred in only 2 cases. Altogether, PDGFRA-mutated GISTs display the same chromosomal aberrations as KIT-mutated GISTs, although they have a lower degree of chromosomal instability in line with their generally favorable outcome.

STAT3 inhibition sensitizes colorectal cancer to chemoradiotherapy in vitro and in vivo

Increased activity of signal transducer and activator of transcription 3 (STAT3) is common in human malignancies, including colorectal cancers (CRCs). We have recently reported that STAT3 gene expression correlates with resistance of CRC cell lines to 5-fluorouracil (5-FU)-based chemoradiotherapy (CT/RT). This is of considerable clinical importance, because a large proportion of rectal cancers are resistant to preoperative multimodal treatment. To test whether STAT3 contributes to CT/RT-resistance, we first confirmed that STAT3 protein expression correlated positively with increasing resistance. While STAT3 was not constitutively active, stimulation with interleukin-6 (IL-6) resulted in remarkably higher expression levels of phosphorylated STAT3 in CT/RT-resistant cell lines. A similar result was observed when we determined IL-6-induced expression levels of phosphorylated STAT3 following irradiation. Next, STAT3 was inhibited in SW480 and SW837 using siRNA, shRNA and the small-molecule inhibitor STATTIC. Successful silencing and inhibition of phosphorylation was confirmed using Western blot analysis and a luciferase reporter assay. RNAi-mediated silencing as well as STATTIC treatment resulted in significantly decreased clonogenic survival following exposure to 3 µM of 5-FU and irradiation in a dose-dependent manner, with dose-modifying factors of 1.3-2.5 at a surviving fraction of 0.37. Finally, STAT3 inhibition led to a profound CT/RT-sensitization in a subcutaneous xenograft model, with a significantly delayed tumor regrowth in STATTIC-treated mice compared with control animals. These results highlight a potential role of STAT3 in mediating treatment resistance and provide first proof of concept that STAT3 represents a promising novel molecular target for sensitizing resistant rectal cancers to CT/RT.

Integration of metabolomics and transcriptomics revealed a fatty acid network exerting growth inhibitory effects in human pancreatic cancer

PURPOSE

To identify metabolic pathways that are perturbed in pancreatic ductal adenocarcinoma (PDAC), we investigated gene-metabolite networks with integration of metabolomics and transcriptomics.

EXPERIMENTAL DESIGN

We conducted global metabolite profiling analysis on two independent cohorts of resected PDAC cases to identify critical metabolites alteration that may contribute to the progression of pancreatic cancer. We then searched for gene surrogates that were significantly correlated with the key metabolites, by integrating metabolite and gene expression profiles.

RESULTS

Fifty-five metabolites were consistently altered in tumors as compared with adjacent nontumor tissues in a test cohort (N = 33) and an independent validation cohort (N = 31). Weighted network analysis revealed a unique set of free fatty acids (FFA) that were highly coregulated and decreased in PDAC. Pathway analysis of 157 differentially expressed gene surrogates revealed a significantly altered lipid metabolism network, including key lipolytic enzymes PNLIP, CLPS, PNLIPRP1, and PNLIPRP2. Gene expressions of these lipases were significantly decreased in pancreatic tumors as compared with nontumor tissues, leading to reduced FFAs. More importantly, a lower gene expression of PNLIP in tumors was associated with poorer survival in two independent cohorts. We further showed that two saturated FFAs, palmitate and stearate, significantly induced TRAIL expression, triggered apoptosis, and inhibited proliferation in pancreatic cancer cells.

CONCLUSIONS

Our results suggest that impairment in a lipolytic pathway involving lipases, and a unique set of FFAs, may play an important role in the development and progression of pancreatic cancer and provide potential targets for therapeutic intervention.

FOXL1, a novel candidate tumor suppressor, inhibits tumor aggressiveness and predicts outcome in human pancreatic cancer

The forkhead box L1 (FOXL1) transcription factor regulates epithelial proliferation and development of gastrointestinal tract and has been implicated in gastrointestinal tumorigenesis in mouse models. However, the role of FOXL1 in pancreatic cancer development and progression remains to be elucidated. Here, we report that higher expression of FOXL1 is significantly associated with better clinical outcome in human pancreatic ductal adenocarcinoma (PDAC). A lower FOXL1 expression is correlated with metastasis and advanced pathologic stage of pancreatic cancer. Mechanistic analyses showed that overexpression of FOXL1 induces apoptosis and inhibits proliferation and invasion in pancreatic cancer cells, whereas silencing of FOXL1 by siRNA inhibits apoptosis and enhances tumor cell growth and invasion. Furthermore, FOXL1 overexpression significantly suppressed the growth of tumor xenografts in nude mice. FOXL1 promoted apoptosis partly through the induction of TNF-related apoptosis-inducing ligand (TRAIL) in pancreatic cancer cells. In addition, FOXL1 suppressed the transcription of zinc finger E-box-binding homeobox 1 (ZEB1), an activator of epithelial-mesenchymal transition, and the negative regulation of ZEB1 contributed to the inhibitory effect of FOXL1 on tumor cell invasion. Taken together, our findings suggest that FOXL1 expression is a candidate predictor of clinical outcome in patients with resected PDAC and it plays an inhibitory role in pancreatic tumor progression.

Abstract 68: Targeting STAT3 in vitro and in vivo reveals a novel therapeutic strategy to sensitize colorectal cancer cells to chemoradiotherapy

Introductory sentence:

Increased activity of signal transducer and activator of transcription 3 (STAT3) is common in human malignancies, including colorectal cancers. Recently, we reported that STAT3 expression correlated with resistance to 5-fluorouracil (5-FU) based chemoradiotherapy. This is of considerable clinical relevance, because a large proportion of rectal cancers are resistant to preoperative multimodal treatment. We therefore examined whether STAT3 contributes to resistance to chemoradiotherapy.

Experimental procedures:

STAT3 mRNA and protein expression levels were determined in 12 colorectal cancers cell lines. STAT3 was inhibited using two different siRNAs and a small-molecular inhibitor (STATTIC) in the cell lines SW480 and SW837. Successful RNAi-mediated silencing of STAT3 or inhibition of phosphoSTAT3(Tyr705) was detected by Western blot and reduction of transcription factor activity was measured by a luciferase reporter assay. Additionally, we established doxycycline-inducible stable shRNA single cell populations and a non-silencing shRNA (shNEG) in SW480. To test the influence of STAT3 knock down or inhibition, clonogenic survival assays were performed. Therefore, RNAi or inhibitor treated cells were exposed to chemoradiotherapy using 3μM 5-FU and X-ray-irradiation at 1, 2, 4, 6, and 8 Gy. Finally, we tested the effect of a chemoradiotherapy combined with STATTIC treatment in a SW837 xenograft model in NMRI nude mice. To verify the sensitizing effect of STATTIC, tumor growth was recorded and growth delay assays were performed.

Data:

STAT3 was overexpressed in resistant cells at mRNA and protein level. siRNA transfected SW480, SW837, and SW480shRNA single cell clones showed a significant reduction of STAT3 protein and transcription factor activity after 96 hours. STATTIC inhibition led to a decreased phosphorylation of STAT3 after 1 hour. The silencing/inhibition resulted in a significantly increased chemoradiosensitivity with dose-reduction factors of 1.3 to 2.5 at a surviving fraction of 0.37. In vivo, additional STAT3 inhibition during chemoradiotherapy led to a profound chemoradiosensitization effect and a significant tumor growth delay in STATTIC treated mice. Survival of these mice was also enhanced, if compared to the control group.

Conclusions:

STAT3 is highly overexpressed in resistant colorectal cancer cells, and silencing or inhibition of STAT3 leads to a significantly increased chemoradiosensitivity in vitro and in vivo. This highlights the potential relevance of STAT3 for mediating treatment resistance and provides a first proof of concept that STAT3 represents a novel molecular target in rectal cancer to sensitize a priori resistant colorectal tumor cells to chemoradiotherapy.

Citation Format: Melanie Spitzner, Birte Roesler, Christian Bielfeld, Carolin Herzberg, Georg Emons, Jochen Gaedcke, Margret Rave-Fränk, Tim Beißbarth, Thomas Ried, B. Michael Ghadimi, Marian Grade. Targeting STAT3 in vitro and in vivo reveals a novel therapeutic strategy to sensitize colorectal cancer cells to chemoradiotherapy. [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 68. doi:10.1158/1538-7445.AM2013-68

Increased growth of colorectal liver metastasis following partial hepatectomy

Nearly 50 % of colorectal cancer (CRC) patients develop liver metastases with liver resection being the only option to cure patients. Residual micrometastases or circulating tumor cells are considered a cause of tumor relapse. This work investigates the influence of partial hepatectomy (PH) on the growth and molecular composition of CRC liver metastasis in a syngeneic rat model. One million CC531 colorectal tumor cells were implanted via the portal vein in WAG/Rij rats followed by a 30 % PH a day later. Control groups either received tumor cells followed by a sham-operation or were injected with a buffer solution followed by PH. Animals were examined with magnetic resonance imaging (MRI) and liver tissues were processed for immunolabeling and PCR analysis. One-third PH was associated with an almost threefold increase in relative tumor mass (MRI volumetry: 2.8-fold and transcript levels of CD44: 2.3-fold). Expression of molecular markers for invasiveness and aggressiveness (CD49f, CXCR4, Axin2 and c-met) was increased following PH, however with no significant differences when referring to the relative expression levels (relating to tumor mass). Liver metastases demonstrated a significantly higher proliferation rate (Ki67) 2 weeks following PH and cell divisions also increased in the surrounding liver tissue. Following PH, the stimulated growth of metastases clearly exceeded the compensation in liver volume with long-lasting proliferative effects. However, the distinct tumor composition was not influenced by liver regeneration. Future investigations should focus on the inhibition of cell cycle (i.e. systemic therapy strategies, irradiation) to hinder liver regeneration and therefore restrain tumor growth.

Association of CD133 expression levels with the k-ras mutation status in rectal cancers before and after preoperative radiochemotherapy

400

Background: The role of the potential stem cell marker CD133 as a predictive or prognostic marker in multimodal rectal cancer treatment is currently under debate. While CD133 has been identified as a prognostic marker in rectal cancers after preoperative radiochemotherapy (RCT) it was recently characterized as a very unspecific feature for colorectal cancer stem cells. We therefore analyzed the association between CD133 expression and mutations in the proto-oncogenes K-Ras and PI3K in rectal cancer patients receiving neoadjuvant RCT. Methods: CD133 expression was evaluated immunhistochemically in pre-treatment biopsies and surgical specimens of 128 patients with locally advanced rectal cancers (cUICC II/III) treated with preoperative RCT within the phase-III German Rectal Cancer Trials. K-Ras mutations were analyzed by sequencing of exons 1, 2, and 3. PI3K mutations were detected by sequencing the p110α subunit (PIK3CA) and correlated with histopathologic parameters, tumor regression and survival. Results: CD133 expression was significantly associated with mutations in the K-Ras gene in both pre-treatment biopsies and post-treatment tumor specimens in uni- and multivariate analyses. However, no significant correlation was observed between CD133 and PI3K mutations. Post-treatment CD133 levels were correlated with neoadjuvant RCT (50.4 Gy/5-FU vs. 50.4 Gy/5-FU+Ox) and tumor regression grading. Anyway, there was no significant association between pre- and post-treatment CD133 expression and disease-free survival. Conclusions: CD133 expression levels are strongly associated with mutations in the K-Ras proto-oncogene in rectal cancers before and after preoperative RCT. Our results strengthen the hypothesis that CD133 is not a specific marker for colorectal stem cells but might be integrated in proliferation pathways like the ras-raf axis.

Genetic amplification of the NOTCH modulator LNX2 upregulates the WNT/β-catenin pathway in colorectal cancer

Chromosomal copy number alterations (aneuploidy) define the genomic landscape of most cancer cells, but identification of the oncogenic drivers behind these imbalances remains an unfinished task. In this study, we conducted a systematic analysis of colorectal carcinomas that integrated genomic copy number changes and gene expression profiles. This analysis revealed 44 highly overexpressed genes mapping to localized amplicons on chromosome 13, gains of which occur often in colorectal cancers (CRC). RNA interference (RNAi)-mediated silencing identified eight candidates whose loss-of-function reduced cell viability 20% or more in CRC cell lines. The functional space of the genes NUPL1, LNX2, POLR1D, POMP, SLC7A1, DIS3, KLF5, and GPR180 was established by global expression profiling after RNAi exposure. One candidate, LNX2, not previously known as an oncogene, was involved in regulating NOTCH signaling. Silencing LNX2 reduced NOTCH levels but also downregulated the transcription factor TCF7L2 and markedly reduced WNT signaling. LNX2 overexpression and chromosome 13 amplification therefore constitutively activates the WNT pathway, offering evidence of an aberrant NOTCH-WNT axis in CRC.

PAM4 enzyme immunoassay alone and in combination with CA 19-9 for the detection of pancreatic adenocarcinoma

BACKGROUND

The monoclonal antibody PAM4 has high specificity for pancreatic ductal adenocarcinoma (PDAC), as well as its precursor lesions, but has not been found to be reactive with normal and benign pancreatic tissues. The objective of the current study was to evaluate a PAM4-based serum enzyme immunoassay alone and in combination with the carbohydrate antigen (CA) 19-9 assay for the detection of PDAC, with particular attention to early stage disease.

METHODS

Sera from patients with confirmed PDAC (N = 298), other cancers (N = 99), benign disease of the pancreas (N = 120), and healthy adults (N = 79) were evaluated by a specific enzyme immunoassay for the concentration of PAM4 and CA 19-9 antigen levels by blinded analyses. All tests for statistical significance were 2-sided.

RESULTS

The overall sensitivity for PAM4 detection of PDAC was 76%, with 64% of patients with stage I disease also identified. The detection rate was considerably higher (85%) for patients with advanced disease. The assay demonstrated high specificity compared with benign pancreatic disease (85%), with a positive likelihood ratio of 4.93. CA 19-9 provided an overall sensitivity of 77%, and was positive in 58% of patients with stage I disease; however, the specificity was significantly lower for CA 19-9 (68%), with a positive likelihood ratio of 2.85 (P = .026 compared with PAM4). It is important to note that a combined PAM4 and CA 19-9 biomarker serum assay demonstrated an improved sensitivity (84%) for the overall detection of PDAC without a significant loss of specificity (82%) compared with either arm alone.

CONCLUSIONS

The PAM4 enzyme immunoassay identified approximately two-thirds of patients with stage I PDAC with high discriminatory power with respect to benign, nonneoplastic pancreatic disease. These results provide a rationale for testing patient groups considered to be at high risk for PDAC with a combined PAM4 and CA 19-9 biomarker serum assay for the detection of early stage PDAC.

Serum mesothelin and megakaryocyte potentiating factor in pancreatic and biliary cancers

BACKGROUND

Tumor mesothelin overexpression is present in different malignancies, including the majority of patients with pancreatic or biliary cancers. The objective of this study was to evaluate the use of shed serum mesothelin and megakaryocyte potentiating factor (MPF) concentrations as biomarkers for these cancers.

METHODS

A total of 151 individuals, divided into five groups, were retrospectively analyzed: healthy donors (n=15), patients with benign non-pancreatic conditions (n=52), benign pancreatic conditions (n=33), biliary carcinoma (n=9), and pancreatic ductal adenocarcinoma (n=42). Mesothelin and MPF concentrations were measured in serum with the Mesomark™ and Human MPF ELISA, respectively.

RESULTS

Mesothelin and MPF concentrations did not significantly differ among the five individual participant groups (p=0.34, p=0.33, respectively), nor did any other combination and pair-wise comparison of the participant groups demonstrated a significant difference in biomarker concentrations. In patients with pancreatic cancer, mesothelin or MPF concentrations were not associated with tumor stage (p=0.87, p=0.48, respectively) or differentiation grade (p=0.73, p=0.52, respectively).

CONCLUSIONS

Serum mesothelin and MPF concentrations, measured with standard available ELISAs, were not specific for benign or pancreatic disease. Both biomarkers were not elevated in patients with pancreatic or biliary cancers, and consequently do not appear to be useful biomarkers for these malignancies.

The rectal cancer microRNAome--microRNA expression in rectal cancer and matched normal mucosa

PURPOSE

miRNAs play a prominent role in a variety of physiologic and pathologic biologic processes, including cancer. For rectal cancers, only limited data are available on miRNA expression profiles, whereas the underlying genomic and transcriptomic aberrations have been firmly established. We therefore, aimed to comprehensively map the miRNA expression patterns of this disease.

EXPERIMENTAL DESIGN

Tumor biopsies and corresponding matched mucosa samples were prospectively collected from 57 patients with locally advanced rectal cancers. Total RNA was extracted, and tumor and mucosa miRNA expression profiles were subsequently established for all patients. The expression of selected miRNAs was validated using semi-quantitative real-time PCR.

RESULTS

Forty-nine miRNAs were significantly differentially expressed (log(2)-fold difference >0.5 and P < 0.001) between rectal cancer and normal rectal mucosa. The predicted targets for these miRNAs were enriched for the following pathways: Wnt, TGF-beta, mTOR, insulin, mitogen-activated protein kinase, and ErbB signaling. Thirteen of these 49 miRNAs seem to be rectal cancer-specific, and have not been previously reported for colon cancers: miR-492, miR-542-5p, miR-584, miR-483-5p, miR-144, miR-2110, miR-652, miR-375, miR-147b, miR-148a, miR-190, miR-26a/b, and miR-338-3p. Of clinical impact, miR-135b expression correlated significantly with disease-free and cancer-specific survival in an independent multicenter cohort of 116 patients.

CONCLUSION

This comprehensive analysis of the rectal cancer miRNAome uncovered novel miRNAs and pathways associated with rectal cancer. This information contributes to a detailed view of this disease. Moreover, the identification and validation of miR-135b may help to identify novel molecular targets and pathways for therapeutic exploitation.

Enrichment of CD133-expressing cells in rectal cancers treated with preoperative radiochemotherapy is an independent marker for metastasis and survival

BACKGROUND

The transmembrane glycoprotein CD133 (cluster of differentiation 133; also known as Prominin or PROM1) has been described as a potential stem cell marker in colorectal cancer and is associated with higher tumorigenic potential and resistance to radiochemotherapy (RCT). In this study, CD133 expression was evaluated in pre-RCT tumor biopsies and the corresponding post-RCT surgical specimens from patients with locally advanced rectal adenocarcinoma, and expression levels were correlated with histopathologic features and clinical follow-up.

METHODS

One hundred twenty-six patients with International Union Against Cancer (UICC) stage II/III rectal cancer who received preoperative 5-fluorouracil (5-FU)-based RCT within the German Rectal Cancer Trials were investigated. Pre-RCT and post-RCT CD133 expression levels were determined using immunohistochemistry and were correlated with histopathologic parameters, tumor regression grade, cancer recurrence, and patient survival.

RESULTS

Compared with pre-RCT biopsies, significantly higher CD133 expression was observed in tumor specimens (P = .01). However, no correlations were observed for either biopsies or tumor specimens between CD133 expression levels, histopathologic characteristics, or survival. In matched analyses of corresponding biopsy/tumor pairs, patients who had an increased fraction of CD133-expressing (CD133+) cells after preoperative RCT had significantly higher residual tumor stages (P = .02) and lower histopathologic tumor regression (P < .01). Moreover, these patients had significantly reduced disease-free survival and cancer-specific overall survival in univariate analysis (P < .001 and P = .004, respectively) and multivariate analysis (P = .003 and P = .024, respectively).

CONCLUSIONS

The enrichment of CD133+ cancer cells during preoperative RCT was correlated with minor local tumor response, increased distant cancer recurrence, and decreased survival. The current results indicate that the up-regulation of intratumoral CD133 expression, in contrast to absolute pre-RCT and post-RCT CD133 levels, plays an important role in tumor progression and metastasis in patients with rectal cancer who are receiving neoadjuvant RCT.

HER2 status in locally advanced rectal cancer and metachronous metastases: Opportunity for a new therapeutic approach?

3600

Background: Even though the implementation of multimodal treatment strategies including neoadjuvant radiochemotherapy (RCT) has led to improved survival distant metastases are still limiting the prognosis of rectal cancer patients. In this context, we investigated the HER-2 status in rectal cancer patients, UICC stages II and III. Our aim was to assess the HER-2 positivity rate in primary tumors and metachronous metastases. Methods: In this study 264 rectal cancer patients (192 male, 72 female; median age 64 years) from phase-II/-III-trials of the German Rectal Cancer Study Group (CAO/ARO/AIO-94 and 04) were included. HER-2 status was determined pretherapeutically in tumor biopsies as well as resection specimens and metachronous metastases (n=27) using immunohistochemistry (IHC0 to IHC3+) scoring and S-ISH-amplification detection. Tumors with IHC3+ or S-ISH ratio ?2.0 were classified as HER-2 positive; results were correlated with clinicopathological parameters and long-term survival. Results: A positive HER-2 status was found in 12.4% of pre-treatment biopsies, in 29.3% of the resection specimens and 22.2% (n=6) of metastases. With a median follow-up of 46.5 months patients with HER-2-positivity showed better disease free survival (p=0.06) and cancer-specific survival (CSS, p=0.05). The 5-years survival rate was 96.4% (HER-2-positive) versus 79.5% (HER-2-negative). In multivariate analyses HER-2 status was as an independent (p=0.0053) predictor for CSS along with (y)pN-status (p<0.0001) and R-status (p=0.023). Conclusions: HER-2 amplification is detectable in a significant proportion (about 30%) of primary tumors of patients with advanced rectal cancer. Furthermore HER-2 amplification was detectable in 22% of resected metachronous metastases during follow-up. Therefore HER-2 represents a promising target and should be further assessed within prospective clinical trials.