JAK/STAT3 represents a therapeutic target for colorectal cancer patients with stromal-rich tumors

Colorectal cancer (CRC) is a heterogenous malignancy underpinned by dysregulation of cellular signaling pathways. Previous literature has implicated aberrant JAK/STAT3 signal transduction in the development and progression of solid tumors. In this study we investigate the effectiveness of inhibiting JAK/STAT3 in diverse CRC models, establish in which contexts high pathway expression is prognostic and perform in depth analysis underlying phenotypes. In this study we investigated the use of JAK inhibitors for anti-cancer activity in CRC cell lines, mouse model organoids and patient-derived organoids. Immunohistochemical staining of the TransSCOT clinical trial cohort, and 2 independent large retrospective CRC patient cohorts was performed to assess the prognostic value of JAK/STAT3 expression. We performed mutational profiling, bulk RNASeq and NanoString GeoMx® spatial transcriptomics to unravel the underlying biology of aberrant signaling. Inhibition of signal transduction with JAK1/2 but not JAK2/3 inhibitors reduced cell viability in CRC cell lines, mouse, and patient derived organoids (PDOs). In PDOs, reduced Ki67 expression was observed post-treatment. A highly significant association between high JAK/STAT3 expression within tumor cells and reduced cancer-specific survival in patients with high stromal invasion (TSPhigh) was identified across 3 independent CRC patient cohorts, including the TrasnSCOT clinical trial cohort. Patients with high phosphorylated STAT3 (pSTAT3) within the TSPhigh group had higher influx of CD66b + cells and higher tumoral expression of PDL1. Bulk RNAseq of full section tumors showed enrichment of NFκB signaling and hypoxia in these cases. Spatial deconvolution through GeoMx® demonstrated higher expression of checkpoint and hypoxia-associated genes in the tumor (pan-cytokeratin positive) regions, and reduced lymphocyte receptor signaling in the TME (pan-cytokeratin- and αSMA-) and αSMA (pan-cytokeratin- and αSMA +) areas. Non-classical fibroblast signatures were detected across αSMA + regions in cases with high pSTAT3. Therefore, in this study we have shown that inhibition of JAK/STAT3 represents a promising therapeutic strategy for patients with stromal-rich CRC tumors. High expression of JAK/STAT3 proteins within both tumor and stromal cells predicts poor outcomes in CRC, and aberrant signaling is associated with distinct spatially-dependant differential gene expression.

Protein expression of S100A2 reveals it association with patient prognosis and immune infiltration profile in colorectal cancer

PURPOSE

Colorectal cancer (CRC) is the third most diagnosed cancer worldwide. Despite a well-established knowledge of tumour development, biomarkers to predict patient outcomes are still required. S100 calcium-binding protein A2 (S100A2) has been purposed as a potential marker in many types of cancer, however, the prognostic value of S100A2 in CRC is rarely reported.

MATERIAL AND METHODS

In this study, immunohistochemistry (IHC) was performed to identify the prognostic role of S100A2 protein expression in the tumour core of the tissue microarrays (TMAs) in colorectal cancer patients (n=787). Bulk RNA transcriptomic data was used to identify significant genes compared between low and high cytoplasmic S100A2 groups. Multiplex immunofluorescence (mIF) was performed to further study and confirm the immune infiltration in tumours with low and high cytoplasmic S100A2.

RESULTS

Low cytoplasmic protein expression of S100A2 in the tumour core was associated with poor survival (HR 0.539, 95%CI 0.394-0.737, P<0.001) and other adverse tumour phenotypes. RNA transcriptomic analysis showed a gene significantly associated with the low cytoplasmic S100A2 group (AKT3, TAGLN, MYLK, FGD6 and ETFDH), which correlated with tumour development and progression. GSEA analysis identifies the enriched anti-tumour and immune activity group of genes in high cytoplasmic S100A2. Additionally, mIF staining showed that high CD3+FOXP3+ and CD163+ inversely associated with low cytoplasmic S100A2 (P<0.001, P=0.009 respectively).

CONCLUSION

Our finding demonstrates a prognostic value of S100A2 together with the correlation with immune infiltration in CRC.

Spatially Resolved Transcriptomics Deconvolutes Prognostic Histological Subgroups in Patients with Colorectal Cancer and Synchronous Liver Metastases

Strong immune responses in primary colorectal cancer correspond with better patient survival following surgery compared with tumors with predominantly stromal microenvironments. However, biomarkers to identify patients with colorectal cancer liver metastases (CRLM) with good prognosis following surgery for oligometastatic disease remain elusive. The aim of this study was to determine the practical application of a simple histological assessment of immune cell infiltration and stromal content in predicting outcome following synchronous resection of primary colorectal cancer and CRLM and to interrogate the underlying functional biology that drives disease progression. Samples from patients undergoing synchronous resection of primary colorectal cancer and CRLM were evaluated in detail through histological assessment, panel genomic and bulk transcriptomic assessment, IHC, and GeoMx spatial transcriptomics (ST) analysis. High immune infiltration of metastases was associated with improved cancer-specific survival. Bulk transcriptomic analysis was confounded by stromal content, but ST demonstrated that the invasive edge of the metastases of long-term survivors was characterized by adaptive immune cell populations enriched for type II IFN signaling and MHC-class II antigen presentation. In contrast, patients with poor prognosis demonstrated increased abundance of regulatory T cells and neutrophils with enrichment of Notch and TGFβ signaling pathways at the metastatic tumor center. In summary, histological assessment can stratify outcomes in patients undergoing synchronous resection of CRLM, suggesting that it has potential as a prognostic biomarker. Furthermore, ST analysis has revealed significant intratumoral and interlesional heterogeneity and identified the underlying transcriptomic programs driving each phenotype.

SIGNIFICANCE

Spatial transcriptomics uncovers heterogeneity between patients, between matched lesions in the same patient, and within individual lesions and identifies drivers of metastatic progression in colorectal cancer with reactive and suppressed immune microenvironments.

Abstract 3231: Temporal changes in intratumoral and systemic lymphocytes in response to short and long course radiotherapy regimens in locally advanced rectal cancer

Background. Two pre-operative radiotherapy (RT) regimens are in common use for patients (pts) with locally advanced rectal cancer (LARC): Conventionally fractionated, long course chemoradiation (LCCRT, 25x1.8Gy with concomitant chemotherapy) or hypofractionated short-course RT (5X5Gy) followed by systemic chemotherapy (SCRT-C). RT is thought to induce immune responses to cellular damage, but the understanding of their evolution and relation to fractionation is limited. We are conducting a serial biospecimen collection in such pts with baseline, 2, 6 and 12 week (wk) sampling. We report serial measurement of tumor and peripheral blood lymphocyte responses for each regimen.

Method. Multiplex immunofluorescence quantified tumor infiltrating lymphocytes (CD8, FOXP3). Routine diagnostic flow cytometry quantified circulating lymphocytes. A multiplex ELISA quantified cytokines in blood plasma. Bulk RNA-sequencing (QuantSeq) quantified gene expression within the tumor.

Result. We report results for 20pts who received RT for stage III/IV LARC (13 LCCRT, 7 SCRT-C). Biopsy results are available for 10pts, circulating lymphocytes for 20pts and peripheral blood cytokines for 16pts. In LCCRT patients (n=8), relative to baseline, tumor infiltrating cytotoxic (CD8+) T cells were uniformly decreased during (2wks, P&lt;0.05) and directly after treatment (6wks, P&lt;0.05) before returning to baseline at 12wks. T regulatory cells (FOXP3+) similarly significantly decreased at 2wks and 6wks but remained below baseline at 12wks (P&lt;0.05). Circulating lymphocytes also fell at wk2 and wk6 after commencing LCCRT and had begun recovering by wk12(n=13; P&lt;0.05). The concentrations of circulating interleukins secreted by (IL2, IL8) or which activate T-lymphocytes (IL2, IL15) were reduced in the circulation at wk2 (n= 9; P&lt;0.05) and wk6 (NS). In SCRT-C patients, we noted an increase in CD8 T cells at 2wks in 2/2 pts, also reflected in gene expression data, and an increase in FOXP3 T cells in 1/2 pts. Circulating lymphocytes were similarly decreased at wk2 in both the SCRT-C (n=7) and LCCRT (n=13) pts, but this reduction was less marked within the SCRT-C cohort at wk6 (P&lt;0.01) and wk12 (P&lt;0.05) relative to LCCRT patients. IL2, IL8 and IL15 did not change during or after SCRT-C (n=7; NS).

Conclusion. LCCRT caused a drop in T cells during treatment, whilst SCRT-C appears to induce intra-tumoral T cell responses from wk2 and abrogates systemic reactions to a lesser extent. These results require evaluation in a larger cohort but have implications for understanding how RT induces microenvironmental changes and impacts pelvic bone marrow. We show in vivo that SCRT may be more immunostimulatory in LARC, with implications for trials combining RT with immunotherapy.

Citation Format: Lily V. Hillson, Ross K. McMahon, Kathryn A. Pennel, Jean A. Quinn, Leia Jones, Raheleh Amirkhah, Aula Ammar, Phimmada Hatthakarnkul, Annabelle Ferguson, Simon W. Milling, Alec McDonald, Philip D. Dunne, Joanne Edwards, Sean M. O'Cathail, Campbell S. Roxburgh. Temporal changes in intratumoral and systemic lymphocytes in response to short and long course radiotherapy regimens in locally advanced rectal cancer [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 3231.

Carbonic anhydrase IX-related tumoral hypoxia predicts worse prognosis in breast cancer: A systematic review and meta-analysis

Background

Tumoral hypoxia is associated with aggressiveness in many cancers including breast cancer. However, measuring hypoxia is complicated. Carbonic anhydrase IX (CAIX) is a reliable endogenous marker of hypoxia under the control of the master regulator hypoxia-inducible factor-1α (HIF-1α). The expression of CAIX is associated with poor prognosis in many solid malignancies; however, its role in breast cancer remains controversial.

Methods

The present study performed a meta-analysis to evaluate the correlation between CAIX expression and disease-free survival (DFS) and overall survival (OS) in breast cancer.

Results

A total of 2,120 publications from EMBASE, PubMed, Cochrane, and Scopus were screened. Of these 2,120 publications, 272 full texts were reviewed, and 27 articles were included in the meta-analysis. High CAIX was significantly associated with poor DFS (HR = 1.70, 95% CI = 1.39–2.07, p &lt; 0.00001) and OS (HR = 2.02, 95% CI 1.40–2.91, p = 0.0002) in patients with breast cancer. When stratified by subtype, the high CAIX group was clearly associated with shorter DFS (HR = 2.09, 95% CI =1.11–3.92, p = 0.02) and OS (HR = 2.50, 95% CI =1.53–4.07, p = 0.0002) in TNBC and shorter DFS in ER+ breast cancer (HR = 1.81 95% CI =1.38–2.36, p &lt; 0.0001).

Conclusion

High CAIX expression is a negative prognostic marker of breast cancer regardless of the subtypes.

Association of punctate TAK1 expression with mortality in patients with microsatellite-stable colorectal cancer

220

Background: Microsatellite stable (MSS) colorectal cancer continues to have limited options for personalised therapeutic targets. The NFKB pathway is known to play an important role in inflammation-related carcinogenesis but has yet to be translated into therapies for the clinical patient. The aim of this study was to investigate the expression of cytoplasmic and punctate TAK1 (transforming growth factor β-activated protein kinase 1) in colorectal cancer and its relationship to immune checkpoint expression and prognosis. Methods: Patients undergoing primary colorectal cancer resection between 1997 and 2007 at Glasgow Royal Infirmary (UK) were studied for clinicopathological data and immunohistochemistry (IHC) performed on archival FFPE tissue from resected specimens. Antibodies for TAK1, PD-1, PD-L1, IKK alpha and other proteins were used for IHC, with digital analysis (QuPath) for quantification of cytoplasmic staining and punctate score for juxta-nuclear TAK1 assessment. Kaplan-Meier curves were created with log-rank test to determine survival. Cox-proportional hazards regression were used to determine multivariate hazard ratios (HR) and 95% confidence intervals (CI). Results: A total of 898 patients who underwent colorectal resection were identified. Higher TAK1 punctate expression was observed in left colon and rectal cancer, compared with right sided disease (p = 0.045). MMR proficient tumours had higher frequencies of high TAK1 punctate expression (p < 0.001). Both cytoplasmic and punctate TAK1 expression correlated with IKK expression (p < 0.050). High cytoplasmic TAK1 expression was associated with increased PD-1 and PD-L1 expression (p < 0.001). Punctate TAK1 expression was associated with worse survival (p = 0.037). These differences were accentuated in patients with MSS status (p = 0.016). On multivariate analysis, high punctate TAK1 expression remained a predictor of worse cancer-specific survival (HR 1.843, CI 1.129-2.956, p = 0.011). Conclusions: TAK1 expression was associated with MSI status, and higher TAK1 expression correlates with upregulated PD-1 and PD-L1 expression. High punctate TAK1 expression predicted cancer-specific survival. In subgroup analysis of MSS patients, high punctate TAK1 expression was associated with poor survival. Further interrogation into this pathway may identify inflammation-related therapeutic targets in MSS patients with colorectal cancer.

CXCL8 expression is associated with advanced stage, right sidedness, and distinct histological features of colorectal cancer

CXCL8 is an inflammatory chemokine elevated in the colorectal cancer (CRC) tumour microenvironment. CXCR2, the major receptor for CXCL8, is predominantly expressed by neutrophils. In the cancer setting, CXCL8 plays important roles in neutrophil chemotaxis, facilitating angiogenesis, invasion, and metastasis. This study aimed to assess the spatial distribution of CXCL8 mRNA expression in CRC specimens, explore associations with clinical characteristics, and investigate the underlying biology of aberrant CXCL8 levels. CXCR2 expression was also assessed in a second cohort of unique CRC primary tumours and synchronously resected matched liver metastases. A previously constructed tissue microarray consisting of a cohort of stage I-IV CRC patients undergoing surgical resection with curative intent (n = 438) was probed for CXCL8 via RNAscope®. Analysis was performed using HALO® digital pathology software to quantify expression in the tumour and stromal compartments. Scores were assessed for association with clinical characteristics. Mutational analyses were performed on a subset of these patients to determine genomic differences in patients with high CXCL8 expression. A second cohort of stage IV CRC patients with primary and matched metastatic liver tumours was stained via immunohistochemistry for CXCR2, and scores were assessed for clinical significance. CXCL8 expression within the stromal compartment was associated with reduced cancer-specific survival in the first cohort (p = 0.035), and this relationship was potentiated in right-sided colon cancer cases (p = 0.009). High CXCL8 within the stroma was associated with driving a more stromal-rich phenotype and the presence of metastases. When stromal CXCL8 scores were combined with tumour-infiltrating macrophage counts or systemic neutrophil counts, patients classified as high for both markers had significantly poorer prognosis. CXCR2+ immune cell infiltration was associated with increased stromal invasion in liver metastases (p = 0.037). These data indicate a role for CXCL8 in driving unfavourable tumour histological features and promoting metastases. This study suggests that inhibiting CXCL8/CXCR2 should be investigated in patients with right-sided colonic disease and stroma-rich tumours.

Serial sampling of rectal tumors during radiotherapy: A proof-of-concept study

153

Background: Treatment response to neoadjuvant therapy in locally advanced rectal cancer (LARC) remains heterogenous. Clinicians are guided by pre-treatment clinical assessment alone in determining neoadjuvant strategy. More must be done to uncover biological mechanisms underpinning response and resistance. We have developed a biospecimen collection protocol in LARC performing serial sampling of tumors and peripheral blood samples prior to, during and after treatment to characterize the biological evolution of this heterogenous response. Here we present early proof of concept results with a focus on the intra-tumoral immune response relating to radiotherapy (RT). Methods: Patients receiving standard-of-care neoadjuvant RT were recruited to an ethically approved study between Dec 2018 - Aug 2021. The protocol consisted of a baseline biopsy and blood sample prior to RT followed by repeat sampling at 2, 6 and 12wks after Day 1 of RT. Standard immunohistochemistry (IHC) was performed for markers of immune activity. Target capture sequencing was performed using RNA baits extracted from serial biopsies to target a 276 genes panel. Paired tumor-normal sequencing was performed. Bulk 3’ RNA seq (Lexogen Illumina Quantseq) characterized immune and inflammatory gene expression. A multiplex bead array (Luminex xPONENT) of 24 cytokines and chemokines was performed using serial plasma samples. Results: 17pts were recruited, 3 with stage IV disease. 14pts received chemoradiation and 3 pts had short-course based regimens. Treatment responses were evaluable in 14pts: graded complete in 2pts; good/ near complete in 7pts and partial/ poor in 5pts. All tumors were MSS, and most frequently mutated genes were APC (75%), KRAS (38%), NRAS (25%) , NOTCH1 (25%) and PIK3CA (25%) (n = 8). Quantseq demonstrated that the immune/ inflammatory response, as measured by interferon-gamma response and IL-6/ JAK-STAT signaling, was significantly elevated up to 12wks after Day 1 RT, with a peak at around 6wks (n = 3). Correlative IHC showed an increase in innate immune cells in pts with a favorable response at 6wks (n = 8). Cytokine/ chemokine analysis suggested patients with a favorable response demonstrated strong inflammatory (MCP1 & IL-17a) responses 2 and 6wks post-RT and strong CTL (Granzyme B) and Th1 (GM-CSF & IP-10) responses 12wks post-RT (n = 10). Conclusions: We show acquisition of meaningful genomic and transcriptomic material from serial biopsies in rectal cancer is possible. Early data suggest that dynamic profiling of rectal tumors demonstrates transcriptomic evolution during treatment. Specifically, we show that the immune response to radiotherapy peaks at around 6wks after initiation of RT and persists to 12wks. This supports ongoing trials of immunomodulatory treatments in combination with, and following, RT in rectal cancer. Further work is required to define differences between responders and non-responders.

Systematic review of tumour budding and association with common mutations in patients with colorectal cancer

INTRODUCTION

Despite a well-known prognostic role in colorectal cancer, the genomic profiling of tumour budding remains to be elucidated. We aim to review the association of common mutations with tumour budding.

METHODS

A systematic review of studies relating to tumour budding and genetic mutation in CRC was performed. The relationship between mutational status and tumour budding was evaluated using meta-analysis.

RESULTS

A total of 6153 patients from 17 articles were included. According to the meta-analysis, high-grade tumour budding was significantly associated with KRAS mutation (OR = 1.52, 95 %CI: 1.13-2.02, P = 0.005) and MSS/pMMR (OR = 2.06, 95 %CI: 1.42-2.97, P = 0.0001).

CONCLUSION

The significant association between high-grade tumour budding and mutated KRAS or MSS/pMMR may suggest a role of these mutations in the development of the tumour budding phenotype and be useful for stratifying patient outcome in CRC.

The relationship between β-catenin and patient survival in colorectal cancer systematic review and meta-analysis

β-catenin is a key component of Wnt signalling, which plays a crucial role in CRC progression. Therefore, a meta-analysis was performed to assess the prognostic value of β-catenin expression in CRC patients. PubMed and Web of Science were searched for relevant publications referring to the association between β-catenin expression and outcome of CRC patients. Review Manager version 5.4 was employed to analysis data from 28 eligible studies (containing 5475 patients). Of these, 6 provided data on DFS, 6 provided data on CSS and 18 reports provided data on OS. High nuclear β-catenin expression was significantly associated with poorer DFS, CSS and OS in patients with CRC whereas, low membranous β-catenin expression was associated to poor OS. In conclusion, β-catenin has prognostic value and potential as a biomarker to stratify patients with CRC. However, further work with high quantity tissue cohorts and patient data is required to confirm this conclusion.

Effect of phenotype on outcome in synchronously resected primary colorectal cancer and matched liver metastases

221

Background: 5-year survival of patients with resectable colorectal liver metastases is 25-40%. Mechanisms of disease progression are heterogenous and do not follow a clearly defined pathway from genotype to phenotype. In stage I-III colorectal cancer (CRC), patients with high tumor stroma exhibit poor prognosis, while those with high immune cell infiltrate do well following resection. We hypothesise that stromally-dense phenotypes lead to T cell exclusion, myeloid cell accumulation and aggressive metastatic progression. Here, we examine relationships between histological tumor phenotype, cellular infiltrate and outcomes in metastatic CRC. Methods: A unique cohort of synchronously resected primary CRC and matched liver metastases (n = 46) were assessed for immune cell infiltration (CD3, CD4, CD8, CD68, CD66b), inflammatory signalling (CXCR2, PDL-1, MMP9) and hypoxia (CAIX) using immunohistochemistry. Tumors were phenotypically subtyped using immune infiltrate (Klintrup-Makinen Grade (KM)), stromal invasion (tumor-stroma percentage (TSP)) and proliferation (Ki67). Results: Phenotypic subtype of primary tumors was predictive of metastatic subtype (rho = 0.522, p = 0.003). Immune phenotypes were associated with good prognosis and stromal phenotypes with poor prognosis (p = 0.004). Infiltration of macrophages and granulocytes associated with poor outcomes (p = 0.018) and increased CXCR2 expression (p = 0.03) at both sites. Increased CXCR2+ cells and macrophages at both sites associated with stromal phenotype (p = 0.02), tumour budding (p = 0.002), low KM grade (p = 0.05) and poor prognosis (p = 0.002). Macrophage and MMP9 levels increased in metastases compared to primary tumour, but no changes were seen in lymphocyte infiltration, CXCR2 and CD66b. Conclusions: Density of immune cell infiltrate, in the primary and metastatic niche, conferred good prognosis. In contrast, stromal, myeloid rich tumors convey poor prognosis. This clinically relevant and histologically efficient process permits segregation of disease and supports further study of relationships in the tumour microenvironment of CRC in the context of chemotherapy to better target therapeutics to individual patients.

IKKα as a potential novel target for treatment of colorectal cancer

174

Background: Colorectal cancer (CRC) is a heterogeneous disease leading to different survival outcomes for patients with the same stage of disease. The non-canonical NF-κB pathway has been shown to have a key role in tumorigenesis, and the aim of this study was to investigate the role of IKKα, the main catalytic component of this pathway in CRC. Methods: A tissue microarray was retrospectively constructed from a patient cohort (1033) with stage I-III CRC who underwent surgery. IHC was utilised to examine cytoplasmic and punctate IKKα expression and determine any association with clincopathological features and cancer specific survival (CSS). To assess IKKα inhibition, organoids were prepared from wild type (WT) mouse colon, mouse models of CRC (Apc and Apc.KRAS.pT53.TGFbR2 (AKPT)) and patient derived human organoids. These were treated with an IKKα inhibitor, SU1433 and organoid size and cell viability assessed. Results: High cytoplasmic expression of IKKα was associated with increasing T stage (p = 0.012), poor tumour differentiation (p = 0.010), tumour necrosis (p = 0.013) and low proliferation status (p = 0.013) but was not associated with CSS. High punctate IKKα expression associated with tumour differentiation (p = 0.001), necrosis (p = 0.004), proliferation (p = 0.044) and MMR competence (p < 0.001) and was also significantly associated with reduced CSS (HR1.20 95%CI 1.02-1.42, p < 0.001). SU1433 did not significantly impact on WT (C57/B16) organoid viability up to a concentration of 1 uM, however organoid size and cell viability was significantly reduced in a dose dependent manner in organoids from both Apc and AKPT mouse models. A similar reduction was observed in patient derived human organoids. Conclusions: Punctate IKKα expression was associated with poor cancer specific survival in CRC patients, and inhibition with SU1433, impacted on CRC mouse and patient derived human organoid size and cell viability. These results suggest that, following further investigation and confirmation, IKKα may be employed as a novel therapeutic target in CRC.

The relationship between members of the canonical NF-kB pathway, tumour microenvironment and cancer specific survival in colorectal cancer patients

BACKGROUND

The aim of this study was to investigate the role of the upstream kinase TAK1 and the canonical NF-κB pathway colorectal in cancer (CRC). Immunohistochemistry was used to assess the expression of TAK1/pTAK1 and canonical NF-κB pathway members in a tissue microarray of 242 patients. The relationship between expression, the tumour microenvironment and cancer-specific survival were examined.

RESULTS

All the investigated members of the pathway were expressed in CRC tissue. In addition, cytoplasmic pTAK1 was associated with the tumour microenvironment (P=0.045) and cancer-specific survival (CSS) (P=0.032). When cytoplasmic pTAK1 was stratified by BRAF status, cytoplasmic pTAK1 expression association with CSS was strengthened (P=0.014). Cytoplasmic IKKβ was significantly associated with the inflammatory cell infiltrate (P=0.015) as graded by Klintrup Makinen grade, systemic inflammation as assessed by neutrophil-lymphocyte ratio (P=0.03) and CSS (P=0.046). On multivariate analysis cytoplasmic IKKβ was independently associated with CSS (HR 1.75,95%CI 1.05-2.91, P=0.033).

CONCLUSION

Cytoplasmic pTAK1 was significantly associated with CSS and this was enhanced in patients with tumours that expressed wild type BRAF. High expression of cytoplasmic IKKβ was significantly associated with decreased CSS and with markers of the tumour microenvironment. These results support the hypothesis that NF-κB pathway members are poor prognostic markers in patients with CRC, but this requires to be validated in a large independent cohort.

The association between markers of tumour cell metabolism, the tumour microenvironment and outcomes in patients with colorectal cancer

Tumour cell anaerobic metabolism has been reported to be a prognostic factor in colorectal cancer. The present study investigated the association between monocarboxylate transporter (MCT) 1, MCT 2, lactate dehydrogenase (LDH) 1 and LDH 5, the tumour microenvironment, and outcome in patients with colorectal cancer. A cohort of 150 patients with stage I-III CRC were utilised to assess tumour cell expression of MCT-1, MCT-2, LDH-1 and LDH-5 by immunohistochemistry. Expression levels were dichotomised and associations with tumour factors, the tumour microenvironment and survival analysed. Nuclear LDH-5 associates with poor prognosis (HR 1.68 95% CI 0.99-2.84, p = 0.050) and trends toward increased tumour stroma percentage (TSP, p = 0.125). Cytoplasmic MCT-2 also trends toward increased TSP (p = 0.081). When combined into a single score; nuclear LDH-5 + TSP significantly associated with decreased survival independent of stage (HR 2.61 95% CI 1.27-5.35, p = 0.009), increased tumour budding (p = 0.002) and decreased stromal T-lymphocytes (p = 0.014). Similarly, cytoplasmic MCT-2 + TSP significantly associated with decreased survival (HR 2.32 95% CI 1.31-4.11, p = 0.003), decreased necrosis (p = 0.039), and increased tumour budding (p = 0.004). The present study reports that the combination of TSP and nuclear LDH-5 was significantly associated with survival, increased tumour budding, and decreased stromal T-lymphocytes. This supports the hypothesis that increased stromal invasion promotes tumour progression via modulation of tumour metabolism. Moreover, MCT-2 and LDH-5 may provide promising therapeutic targets for patients with stromal-rich CRC.

Abstract 4070: The relationship between members of the canonical NF-κB pathway, components of the tumor microenvironment and cancer-specific survival in colorectal cancer patients

The canonical NF-κB pathway regulates the transcription of many genes which may be involved in processes such as inflammation and proliferation, suggesting a potential link between the tumor, the tumor microenvironment and cancer-specific survival in colorectal cancer patients.

Immunohistochemistry was used to assess the expression of the upstream kinase TAK1/pTAK1 and four members of the canonical NF-κB pathway in tissue microarrays. Protein expression was determined using the weighted histoscore method. BRaf status, tumor stroma percentage, local inflammation, systemic inflammation and cancer-specific survival were examined in patients with colorectal cancer.

Cytoplasmic IKKβ was significantly associated with the inflammatory cell infiltrate (p=0.0015), systemic inflammation (p=0.03) and cancer-specific survival (p=0.046). In contrast, no significant association was found with the other three members. Cytoplasmic pTAK1 was associated with the tumor microenvironment (p=0.045) and cancer-specific survival (p=0.032). On multivariate analysis only cytoplasmic IKKβ associated with survival (HR1.75, 95%CI 1.05-291, p=0.033) and this was independent of TNM stage and markers of the tumor microenvironment. When cytoplasmic IKKβ was stratified with BRaf status (wild type (n=151) or mutant (n=48)), it was no longer associated with cancer-specific survival. However, when cytoplasmic pTAK1 was stratified with BRaf status its association with cancer-specific survival was strengthened. Cytoplasmic pTAK1 was significantly associated with cancer-specific survival in patients with wild type BRaf (p=0.014). In patients with BRaf mutations there was no significant association with cancer-specific survival (p=0.105), however the numbers were low and this is currently being investigated in a larger cohort.

The results of the present study show that high expression of cytoplasmic IKKβ was associated with decreased cancer-specific survival and with markers of the tumor microenvironment in patients with colorectal cancer. Expression of cytoplasmic pTAK1 was associated with cancer-specific survival and this was enhanced in patients with tumors expressing wild type BRaf.

Citation Format: Jean A. Quinn, Lindsay Bennett, Meera Patel, Lynette Loi, Mikaela Frixou, Antonia Roseweir, James H. Park, Paul G. Horgan, Donald C. McMillan, Joanne Edwards. The relationship between members of the canonical NF-κB pathway, components of the tumor microenvironment and cancer-specific survival in colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4070.

Tumour infiltrating lymphocyte expression of PD-1 as a favourable prognostic factor in patients with mismatch repair competent colorectal cancer

631

Background: Immune checkpoint activation is recognised in mismatch repair (MMR) deficient colorectal cancer (CRC), and Programmed Cell Death Protein-1 (PD-1) inhibitors have been shown to have therapeutic benefit in this patient group. However, the role of PD-1 and PD Ligand-1 (PDL-1) in patients with MMR competent CRC remains unclear. The present study examined the relationship between tumor infiltrating lymphocyte (TIL) PD-1 and tumour PDL-1 expression, tumour microenvironment (TME) characteristics and cancer-specific survival (CSS) of patients with MMR competent CRC. Methods: The presence of TIL PD-1 and tumour cell PDL-1 expression was examined in patients who had undergone resection of TNM I-III CRC using a tissue microarray. Relationship with clinicopathological characteristics and the TME (Klintrup-Makinen (KM) grade, Immunoscore, tumour stroma percentage (TSP) and Glasgow Microenvironment Score (GMS)) and CSS was examined. Results: 189 patients were included; 64% were older than 65 and 52% were male. PDL-1 expression was not associated with clinicopathological or TME characteristics. Lymphocyte PD-1 expression was not associated with clinicopathological characteristics, but was associated with a high KM grade ( P< 0.001), high Immunoscore ( P< 0.001), low TSP ( P= 0.068) and a low GMS ( P< 0.001). On multivariate survival analysis, high TIL PD-1 expression was associated with improved CSS (HR 0.60, P= 0.016) independent of Immunoscore (HR 0.74, P= 0.03) and TSP (HR 1.91, P= 0.027). PDL1 expression was not associated with CSS on univariate or multivariate analysis. Pre-operative aspirin use was known for 131 patients. Aspirin use showed a trend towards improved 5-year CSS in patients with low PDL-1 expression (100% vs. 77%, P= 0.103) but worse 5-year CSS in those with high expression (55% vs. 82%, P= 0.045). Conclusions: The presence of PD-1 expressing TILs is a favourable prognostic factor in MMR competent CRC independent of other TME characteristics. Furthermore, the relationship between aspirin and CSS may be dependent on PDL-1 expression. Both PD-1 and PDL-1 may be potential prognostic and predictive markers in patients with MMR competent CRC.

The relationship between the non-canonical NF-κB pathway, tumour microenvironment, systemic inflammation and survival in patients undergoing surgery for colorectal caner

631

Background: In patients with colorectal cancer (CRC) the local and systemic inflammatory responses (LIR and SIR) are important determinants of disease progression. The present study examines the association of transcription factor RelB, a key member of the non-canonical NF-κB pathway and its association with LIR and SIR in patients undergoing resection of CRC. Methods: Patients with stage I-III CRC who underwent curative resection in a single institution and were in a previously constructed tissue microarray were studied. IHC was utilised to examine cytoplasmic and nuclear RelB expression. The relationship between RelB, clinicopathological characteristics, LIR (Klintrup-Mäkinen (KM) grade, CD3+ and CD8+T-cell density), SIR and cancer-specific survival (CSS) was examined. Results: 208 patients were included in the analysis. Cytoplasmic RelB (cyto-RelB) was associated with nuclear RelB ( p=0.006). High expression of cyto-RelB was associated with MMR competence ( p=0.010) but not with TNM stage ( p=0.468), venous invasion ( p=0.973), tumour budding ( p=0.068), tumour necrosis ( p=0.786), tumour cell proliferation ( p=0.907), BRAF V600E mutation ( p=0.585) or administration of adjuvant chemotherapy ( p=0.853). High cyto-RelB was inversely associated with mGPS (mGPS >1: low cyto-RelB – 19% vs. high cyto-RelB – 8%, p=0.017). Also, cyto-RelB was inversely associated with tumour inflammatory cell infiltrate at the margin, Klintrup-Mäkinen grade ( p=0.059), (CD3+ p=0.010, CD8+ p=0.007) and in the tumour (CD3+ p=0.002) and a trend with tumour stroma percentage ( p=0.079). High expression of cyto-RelB was not significantly associated with CSS ( p=0.052). Conclusions: In patients undergoing CRC resection, high expression of cyto-RelB was associated with an adverse host local inflammatory response. Up-regulation of the non-canonical NF- κB pathway may be an important mechanism whereby the tumour deregulates local inflammatory responses and evades host immunosurveillance. Further investigation of inflammation based signal transduction pathways in patients with colorectal cancer is warranted.

Abstract B125: The relationship between members of the canonical NF-κB pathway, components of the microenvironment and survival in patients with colorectal cancer

The canonical NF-κB pathway regulates transcription of a wide range of genes involved in various processes including inflammation and proliferation, suggesting that it might provide a link between the systemic inflammatory response (SIR), local inflammatory response (LIR) and tumor signalling, the present study was to examine the relationship between SIR, tumor NF-κB pathway, tumor microenvironment including LIR and cancer specific survival in patients with colorectal cancer

Immunohistochemistry of inhibitory kappa β kinase (IKK)-β, p65 (Rel A) and phosphorylated p65 (p-p65) was performed using colorectal cancer tissue microarray of 151 patients and the weight histoscore method was employed to assess protein expression. The relationship between these proteins, BRAF status, tumor stroma percentage, local inflammation, systemic inflammation, and cancer-specific survival were examined. In addition, western blotting was performed to assess expression of key members of the canonical NF-κB pathway following stimulation with either TNFα or IL-1 in BRAF wildtype (T84) and BRAF V600E mutated cells (HT-29).

Expression of neither p65 nor p-p65, at any cellular location, was associated with clinical outcome measures. However a significant association between cancer specific survival and cytoplasmic IKKβ (p = 0.015), was observed and 10 year survival stratified from 78% to 59%. In addition, when patients were stratified by BRAF status the association with cancer specific survival and cytoplasmic IKKβ was upheld in those patients with wild type BRAF (p = 0.014) but negated in those with mutated BRAF (p = 0.287). Cytoplasmic IKKβ was significantly associated with venous invasion (p = 0.024), immunoscore (p = 0.023), Klintrup-Makinen grade (p = 0.050) and Glasgow microenvironment score. Total cell IKKβ expression was also associated with cancer specific survival, (p = 0.015) and 10 year survival was stratified from 73% to 53%. Total cell IKKβ was significantly associated with TNM (p = 0.004), tumor differentiation (p = 0.001), venous invasion (p = 0.011), necrosis (p = 0.003) and tumor stoma percentage (p = 0.048). In vitro, the canonical NF-κB pathway was induced in colon cancer cell lines T84 and HT-29 by exposure to either TNFα or IL-1 (p-p65 levels increased at 15 min), IKKβ expression remained constant.

In colorectal cancer patients, cytoplasmic and total cell IKKβ expression is associated with cancer specific survival and this was related to tumor microenviroment and LIR but not the SIR. Interactions between stromal and NF-κB pathway may be an important method by which disease progression occurs.

Citation Format: Jean A. Quinn, Lindsay Bennett, Antonia Roseweir, James H. Park, Paul G. Horgan, Donald C. McMillan, Joanne Edwards. The relationship between members of the canonical NF-κB pathway, components of the microenvironment and survival in patients with colorectal cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B125.

Organotypic collagen I assay: a malleable platform to assess cell behaviour in a 3-dimensional context

Cell migration is fundamental to many aspects of biology, including development, wound healing, the cellular responses of the immune system, and metastasis of tumor cells. Migration has been studied on glass coverslips in order to make cellular dynamics amenable to investigation by light microscopy. However, it has become clear that many aspects of cell migration depend on features of the local environment including its elasticity, protein composition, and pore size, which are not faithfully represented by rigid two dimensional substrates such as glass and plastic ¹. Furthermore, interaction with other cell types, including stromal fibroblasts ² and immune cells ³, has been shown to play a critical role in promoting the invasion of cancer cells. Investigation at the molecular level has increasingly shown that molecular dynamics, including response to drug treatment, of identical cells are significantly different when compared in vitro and in vivo⁴.

Ideally, it would be best to study cell migration in its naturally occurring context in living organisms, however this is not always possible. Intermediate tissue culture systems, such as cell derived matrix, matrigel, organotypic culture (described here) tissue explants, organoids, and xenografts, are therefore important experimental intermediates. These systems approximate certain aspects of an in vivo environment but are more amenable to experimental manipulation such as use of stably transfected cell lines, drug treatment regimes, long term and high-resolution imaging. Such intermediate systems are especially useful as proving grounds to validate probes and establish parameters required to image the dynamic response of cells and fluorescent reporters prior to undertaking imaging in vivo ⁵. As such, they can serve an important role in reducing the need for experiments on living animals.

Spatial regulation of RhoA activity during pancreatic cancer cell invasion driven by mutant p53

The ability to observe changes in molecular behavior during cancer cell invasion in vivo remains a major challenge to our understanding of the metastatic process. Here, we demonstrate for the first time, an analysis of RhoA activity at a subcellular level using FLIM-FRET (fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer) imaging in a live animal model of pancreatic cancer. In invasive mouse pancreatic ductal adenocarcinoma (PDAC) cells driven by mutant p53 (p53(R172H)), we observed a discrete fraction of high RhoA activity at both the leading edge and rear of cells in vivo which was absent in two-dimensional in vitro cultures. Notably, this pool of active RhoA was absent in noninvasive p53(fl) knockout PDAC cells, correlating with their poor invasive potential in vivo. We used dasatanib, a clinically approved anti-invasive agent that is active in this model, to illustrate the functional importance of spatially regulated RhoA. Dasatanib inhibited the activity of RhoA at the poles of p53(R172H) cells in vivo and this effect was independent of basal RhoA activity within the cell body. Taken together, quantitative in vivo fluorescence lifetime imaging illustrated that RhoA is not only necessary for invasion, but also that subcellular spatial regulation of RhoA activity, as opposed to its global activity, is likely to govern invasion efficiency in vivo. Our findings reveal the utility of FLIM-FRET in analyzing dynamic biomarkers during drug treatment in living animals, and they also show how discrete intracellular molecular pools might be differentially manipulated by future anti-invasive therapies.

Effect of different classes of gadolinium-based contrast agents on control and nephrogenic systemic fibrosis-derived fibroblast proliferation

PURPOSE

To determine the ability of different types of gadolinium-based contrast agents (GBCAs) to stimulate fibroblast proliferation in monolayer cell culture.

MATERIALS AND METHODS

The National Health Service West Glasgow Ethics Committee granted approval for this study. Fibroblasts established from healthy volunteers (control subjects) and from lesional skin of patients with nephrogenic systemic fibrosis were exposed to a range of concentrations of ionic and nonionic linear and macrocyclic contrast agents over 4 days, and the effect on growth was determined. The lowest concentration of contrast agent that stimulated the maximum effect on fibroblast growth was selected for determination of its effect on fibroblast growth over 8 days. The effect of contrast agents on hyaluronan and collagen synthesis was determined with an enzyme-linked immunosorbent assay. Responses were assessed with analysis of variance (general linear model).

RESULTS

The linear gadolinium contrast agents (gadodiamide, gadoversetamide, gadopentetate dimeglumine, and gadobenate dimeglumine) produced a maximum stimulation of fibroblast proliferation at a concentration of 0.1 mmol/L, with cell numbers increasing up to 2.3-fold. The macrocyclic contrast agents (gadoteric acid and gadoteridol) produced a maximum stimulation of fibroblast proliferation at a concentration of 5 mmol/L. The reference gadolinium agents (N-methylglucamine gadolinium ethylenediaminetetraacetic acid and gadolinium trichloride) stimulated fibroblast proliferation at a concentration of 0.01 mmol/L and were toxic at a concentration greater than 1 mmol/L. Growth curves supported the dose-response observations. Hyaluronan synthesis was stimulated by gadoversetamide, gadobenate dimeglumine, gadodiamide, and gadopentetate dimeglumine at a concentration of 0.1 mmol/L and by gadolinium trichloride at a concentration of 0.01 mmol/L, whereas collagen synthesis was unaffected.

CONCLUSION

This study provides evidence that different classes of gadolinium chelates stimulate human fibroblast proliferation.

A gene on the HER2 amplicon, C35, is an oncogene in breast cancer whose actions are prevented by inhibition of Syk

Background:

C35 is a 12 kDa membrane-anchored protein endogenously over-expressed in many invasive breast cancers. C35 (C17orf37) is located on the HER2 amplicon, between HER2 and GRB7. The function of over-expressed C35 in invasive breast cancer is unknown.

Methods:

Tissue microarrays containing 122 primary human breast cancer specimens were used to examine the association of C35 with HER2 expression. Cell lines over-expressing C35 were generated and tested for evidence of cell transformation in vitro.

Results:

In primary breast cancers high levels of C35 mRNA expression were associated with HER2 gene amplification. High levels of C35 protein expression were associated with hallmarks of transformation, such as, colony growth in soft agar, invasion into collagen matrix and formation of large acinar structures in three-dimensional (3D) cell cultures. The transformed phenotype was also associated with characteristics of epithelial to mesenchymal transition, such as adoption of spindle cell morphology and down-regulation of epithelial markers, such as E-cadherin and keratin-8. Furthermore, C35-induced transformation in 3D cell cultures was dependent on Syk kinase, a downstream mediator of signalling from the immunoreceptor tyrosine-based activation motif, which is present in C35.

Conclusion:

C35 functions as an oncogene in breast cancer cell lines. Drug targeting of C35 or Syk kinase might be helpful in treating a subset of patients with HER2-amplified breast cancers.

4-Methylumbelliferone inhibits tumour cell growth and the activation of stromal hyaluronan synthesis by melanoma cell-derived factors

BACKGROUND

There is a close correlation between tumour progression and hyaluronan production, either by tumour cells or by stromal cells that are stimulated by tumour-derived factors. Inhibition of tumour stimulation of fibroblast hyaluronan may suppress tumour growth and invasion.

OBJECTIVES

To examine the effect of the hyaluronan synthesis inhibitor 4-methylumbelliferone (4-MU) on the growth of and hyaluronan synthesis by fibroblasts and C8161 and MV3 melanoma cell lines, invasion, and inhibition of tumour cell-derived factor activation of fibroblasts.

METHODS

Effects of 4-MU on growth and hyaluronan synthesis by fibroblasts and melanoma cells were examined in monolayer culture and fibroblast-contracted collagen lattices, and their effects on the growth and invasion of tumour cells into collagen lattices were also studied.

RESULTS

4-MU caused a dose-dependent growth inhibition of fibroblast and melanoma cells with maximum inhibition at 0·5 mmol L(-1) 4-MU. At this dose, 4-MU inhibited (3) H-glucosamine incorporation into fibroblast glycosaminoglycans by 52%, and hyaluronan synthesis by 64%. The relative inhibition was more pronounced when fibroblasts were stimulated with C8161 melanoma cell-conditioned medium. 4-MU reduced the level of hyaluronan in fibroblast-contracted collagen lattices, and inhibited both the growth on and invasion into the lattices by melanoma cells. This growth inhibition appears to be predominantly independent of inhibition of hyaluronan synthesis. The effect on growth inhibition was reversible, and 4-MU had no effect on apoptosis.

CONCLUSIONS

4-MU is a potent inhibitor of hyaluronan synthesis, induction of stromal hyaluronan accumulation by tumour cells, and fibroblast and melanoma cell proliferation, and results suggest that 4-MU may have potential as a tumour cell anti-invasive and antiproliferative agent.

Fos cooperation with PTEN loss elicits keratoacanthoma not carcinoma, owing to p53/p21WAF-induced differentiation triggered by GSK3β inactivation and reduced AKT activity

To investigate gene synergism in multistage skin carcinogenesis, the RU486-inducible cre/lox system was employed to ablate Pten function (K14.cre/Δ5Ptenflx) in mouse epidermis expressing activated Fos (HK1.Fos). RU486-treated HK1.Fos/Δ5Ptenflx mice exhibited hyperplasia, hyperkeratosis and tumours that progressed to highly differentiated keratoacanthomas, rather than to carcinomas, owing to re-expression of high p53 and p21WAF levels. Despite elevated MAP kinase activity, cyclin D1 and cyclin E2 overexpression, and increased AKT activity that produced areas of highly proliferative papillomatous keratinocytes, increasing levels of GSK3β inactivation induced a novel p53/p21WAF expression profile, which subsequently halted proliferation and accelerated differentiation to give the hallmark keratosis of keratoacanthomas. A pivotal facet to this GSK3β-triggered mechanism centred on increasing p53 expression in basal layer keratinocytes. This increase in expression reduced activated AKT expression and released inhibition of p21WAF, which accelerated keratinocyte differentiation, as indicated by unique basal layer expression of differentiation-specific keratin K1 alongside premature filaggrin and loricrin expression. Thus, Fos synergism with Pten loss elicited a benign tumour context where GSK3β-induced p53/p21WAF expression continually switched AKT-associated proliferation into differentiation, preventing further progression. This putative compensatory mechanism required the critical availability of normal p53 and/or p21WAF, otherwise deregulated Fos, Akt and Gsk3β associate with malignant progression.

Gadodiamide contrast agent 'activates' fibroblasts: a possible cause of nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) is a fibrotic disease generating intense interest due to its recent discovery, and unknown cause. It appears confined to patients with renal disease and presents as grossly thickened, indurated, tight skin that is woody to palpation. Histologically, the dermis contains thickened collagen bundles, numerous plump fibroblast-like cells, and elevated hyaluronan expression. Recent data suggest a link between the use of gadolinium chelate as an MRI contrast agent and the onset of the disease. Fibroblasts from the lesions of six NSF patients, all of whom were exposed to gadodiamide, were compared with control fibroblasts for hyaluronan and collagen synthesis. Serum from NSF patients was assessed for fibroblast hyaluronan-stimulating activity, collagen synthesis, and gadodiamide for its effect on fibroblast proliferation and matrix synthesis. NSF fibroblasts synthesized excess levels of hyaluronan and collagen compared with control fibroblasts, with up to 2.8-fold and 3.3-fold increases, respectively. NSF patient serum stimulated control fibroblast hyaluronan synthesis by up to 7-fold, and collagen synthesis by up to 2.4-fold. 1 mM gadodiamide added to culture medium stimulated fibroblast growth in a dose-dependent manner, decreasing their doubling time from 28 h to 22 h, and increasing the maximum cell density. Even a short exposure to gadodiamide stimulated cell growth, suggesting that the cells were activated by the gadodiamide. The growth of fibroblasts within contracted collagen lattices was also significantly stimulated by gadodiamide, while fibroblasts exposed to gadodiamide synthesized increased levels of hyaluronan. Control fibroblasts exposed to gadodiamide, and NSF fibroblasts exhibited an extensive pericellular coat of hyaluronan, and expressed alpha-smooth muscle actin. Gadolinium chloride did not affect fibroblast growth. This report demonstrates that NSF fibroblasts synthesize excess levels of hyaluronan and collagen, and that gadodiamide stimulates control fibroblast growth, matrix synthesis, and differentiation into myofibroblasts, suggesting a possible role for gadodiamide in the pathophysiology of NSF.

PTEN loss promotes rasHa-mediated papillomatogenesis via dual up-regulation of AKT activity and cell cycle deregulation but malignant conversion proceeds via PTEN-associated pathways

PTEN tumor suppressor gene failure in ras(Ha)-activated skin carcinogenesis was investigated by mating exon 5 floxed-PTEN (Delta5PTEN) mice to HK1.ras mice that expressed a RU486-inducible cre recombinase (K14.creP). PTEN inactivation in K14.cre/PTEN(flx/flx) keratinocytes resulted in epidermal hyperplasia/hyperkeratosis and novel 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted papillomas, whereas HK1.ras/K14.cre/PTEN(flx/flx) cohorts displayed a rapid onset of papillomatogenesis due to a synergism of increased AKT activity and extracellular signal-regulated kinase (ERK) elevation. High 5-bromo-4-deoxyuridine labeling in Delta5PTEN papillomas showed that a second promotion mechanism centered on failures in cell cycle control. Elevated cyclin D1 was associated with both HK1.ras/ERK- and Delta5PTEN-mediated AKT signaling, whereas cyclin E2 overexpression seemed dependent on PTEN loss. Spontaneous HK1.ras/Delta5PTEN malignant conversion was rare, whereas TPA promotion resulted in conversion with high frequency. On comparison with all previous HK1.ras carcinomas, such TPA-induced carcinomas expressed atypical retention of keratin K1 and lack of K13, a unique marker profile exhibited by TPA-induced K14.cre/PTEN(flx/flx) papillomas that also lacked endogenous c-ras(Ha) activation. Moreover, in all PTEN-null tumors, levels of ras(Ha)-associated total ERK protein became reduced, whereas phosphorylated ERK and cyclin D1 were lowered in late-stage papillomas returning to elevated levels, alongside increased cyclin E2 expression, in TPA-derived carcinomas. Thus, during early papillomatogenesis, PTEN loss promotes ras(Ha) initiation via elevation of AKT activity and synergistic failures in cyclin regulation. However, in progression, reduced ras(Ha)-associated ERK protein and activity, increased Delta5PTEN-associated cyclin E2 expression, and unique K1/K13 profiles following TPA treatment suggest that PTEN loss, rather than ras(Ha) activation, gives rise to a population of cells with greater malignant potential.

What about the other breast? A review of a series of bilateral breast carcinomas

The BreastScreen Queensland Brisbane Southside BreastScreen Service reports on a study of 10 cases of bilateral breast carcinomas from a total cancer population of 217 cases. All cases were patients of screening examinations that were recalled for a suspicious lesion in one breast. Two cases were mammographically suspicious of bilateral tumours. In eight cases, tumours were ultrasonically visible in both breasts and in two further cases, the suspicion of bilateral malignancy was raised by the presence of bilateral microcalcification. It is not the purpose of this paper to provide a statistical analysis of the occurrence of bilateral breast cancer. This is a radiological paper from a breast screening service reporting on findings that conventional wisdom may find unusual. The incidence of bilateral breast malignancy in the study was found to be somewhat higher than expected. These cases have been diagnosed by the utilization of a particularly high standard of ultrasound and mammography, performed and interpreted by diagnosticians possessing an elevated level of suspicion of the possible presence of a second primary lesion. It is therefore proposed that an increased rate of diagnosis of bilateral tumours is possible with an evolution of assessment protocols, combined with quality ultrasound and mammography.

Phase I study of Gliadel wafers plus temozolomide in adults with recurrent supratentorial high-grade gliomas

Both Gliadel wafers [1,3-bis(2-chloroethyl)-1-nitrosourea] and temozolomide (TEMO) have been shown in independent studies to prolong survival of patients with recurrent malignant glioma following surgery and radiotherapy. On the basis of preclinical evidence of synergism between Gliadel wafers and TEMO, a phase I study was designed to evaluate the toxicity of combining these 2 agents in the treatment of patients with recurrent supratentorial malignant glioma. All patients had surgical resection of the tumor at relapse, and up to 8 Gliadel (3.85%) wafers were placed in the surgical cavity following resection. Two weeks after surgery, TEMO was given orally daily for 5 days. Cohorts of 3 patients received TEMO at daily doses of 100 mg/m2, 150 mg/m2, and 200 mg/m2, respectively. Patients were assessed for toxicity 4 weeks after start of the first course of TEMO. Contrast-enhanced MRI of the brain was used to assesstumor response after the first cycle of TEMO. Patients with stable disease or response after the first cycle of TEMO were allowed to continue treatment at the same dose every 4 weeks for 12 cycles or until disease progression or unacceptable toxicity. Ten patients with a median age of 47 years (range, 22-66 years) were enrolled in this study. There were 7 patients with glioblastoma multiforme and 3 patients with anaplastic astrocytoma. Three patients were treated with TEMO at the first dose level of 100 mg/m2, 4 at the second dose level of 150 mg/m2, and 3 at the third dose level of 200 mg/m2. The 10 patients received a median of 3 cycles (range, 1-12 cycles) of TEMO following placement of Gliadel wafers. The treatment was well tolerated, with only 1 patient suffering grade III thrombocytopenia at the highest dose level. Two patients at each dose level had no evidence of disease progression after treatment. Four patients suffered progressive disease on therapy. Our study demonstrates that TEMO can be given safely after placement of Gliadel (3.85%) wafers. The recommended dosage for TEMO for a phase II study of this combination is 200 mg/m2 per day for 5 days.

Analysis of the pobA and pobR genes controlling expression of p-hydroxybenzoate hydroxylase in Azotobacter chroococcum

We report the cloning and analysis of a gene and its cognate regulatory element from a member of the Azotobacteriaceae which are involved in the breakdown of an aromatic compound. The genes from Azotobacter chroococcum encoding p-hydroxybenzoate hydroxylase (pobA) and its regulatory protein (pobR) were cloned from a genomic library and sequenced. Sequence analysis of pobA revealed homology with other bacterial p-hydroxybenzoate hydroxylase enzymes. Residues essential to the structure and function of the enzyme have been conserved. The pobR gene encodes a DNA binding regulatory protein with similarity to proteins from the AraC/XylS family of transcriptional activators. A fragment containing both pobA and pobR was cloned into pUC19 and p-hydroxybenzoate hydroxylase activity was induced in Escherichia coli by the addition of p-hydroxybenzoate. A frame-shift mutation introduced into the pobR gene prevented expression of p-hydroxybenzoate hydroxylase, indicating that PobR is the protein required for transcription of pobA. Interestingly, A. chroococcum PobR has no homology to the PobR protein that is the transcriptional activator of pobA in Acinetobacter strain ADP1, a protein that is homologous to the IclR family of transcriptional regulators. However, PobR from A. chroococcum is homologous to several other proteins, suggesting that these proteins will also function as transcriptional activators of pobA.

Sex expression, sex-specific traits, and the effects of salinity on growth and reproduction of Amaranthus cannabinus (Amaranthaceae), a dioecious annual

Amaranthus cannabinus was studied to investigate some of the ecological factors thought to be involved in the evolution of dioecy and to investigate the effects of salinity on sex expression and sex-specific selection. In the field portion of this study, sex ratios, stability of sex expression, spatial distribution, allocation strategies, and phenologies of the sexes were investigated in New Jersey freshwater and salt marsh populations of water hemp. To examine the effects of salinity on vegetative and reproductive development of males and females, plants were grown in the greenhouse at three salinity levels. Adult sex ratios were found to be 1:1. Temporal deviations from a 1:1 sex ratio varied by population and were due to differences in flowering phenology and mortality between the sexes. No plants were observed to change sex expression, and there was no evidence of spatial segregation of the sexes in the field. In both the field and the greenhouse, females allocated more resources to vegetative tissues and had a longer growing period than males. The results of this study suggest that increased reproductive efficiency through sex-specific growth patterns may have been an important selective factor involved in the evolution of dioecy in A. cannabinus.

Phase I trial of carmustine plus O6-benzylguanine for patients with recurrent or progressive malignant glioma

PURPOSE

The major mechanism of resistance to alkylnitrosourea therapy involves the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT), which removes chloroethylation or methylation damage from the O(6) position of guanine. O(6)-benzylguanine (O(6)-BG) is an AGT substrate that inhibits AGT by suicide inactivation. We conducted a phase I trial of carmustine (BCNU) plus O(6)-BG to define the toxicity and maximum-tolerated dose (MTD) of BCNU in conjunction with the preadministration of O(6)-BG with recurrent or progressive malignant glioma.

PATIENTS AND METHODS

Patients were treated with O(6)-BG at a dose of 100 mg/m(2) followed 1 hour later by BCNU. Cohorts of three to six patients were treated with escalating doses of BCNU, and patients were observed for at least 6 weeks before being considered assessable for toxicity. Plasma samples were collected and analyzed for O(6)-BG, 8-oxo-O(6)-BG, and 8-oxoguanine concentration.

RESULTS

Twenty-three patients were treated (22 with glioblastoma multiforme and one with anaplastic astrocytoma). Four dose levels of BCNU (13.5, 27, 40, and 55 mg/m(2)) were evaluated, with the highest dose level being complicated by grade 3 or 4 thrombocytopenia and neutropenia. O(6)-BG rapidly disappeared from plasma (elimination half-life = 0. 54 +/- 0.14 hours) and was converted to a longer-lived metabolite, 8-oxo-O(6)-BG (elimination half-life = 5.6 +/- 2.7 hours) and further to 8-oxoguanine. There was no detectable O(6)-BG 5 hours after the start of the O(6)-BG infusion; however, 8-oxo-O(6)-BG and 8-oxoguanine concentrations were detected 25 hours after O(6)-BG infusion. The mean area under the concentration-time curve (AUC) of 8-oxo-O(6)-BG was 17.5 times greater than the mean AUC for O(6)-BG.

CONCLUSION

These results indicate that the MTD of BCNU when given in combination with O(6)-BG at a dose of 100 mg/m(2) is 40 mg/m(2) administered at 6-week intervals. This study provides the foundation for a phase II trial of O(6)-BG plus BCNU in nitrosourea-resistant malignant glioma.

Estrogen-induced activation of Erk-1 and Erk-2 requires the G protein-coupled receptor homolog, GPR30, and occurs via trans-activation of the epidermal growth factor receptor through release of HB-EGF

Estrogen rapidly activates the mitogen-activated protein kinases, Erk-1 and Erk-2, via an as yet unknown mechanism. Here, evidence is provided that estrogen-induced Erk-1/-2 activation occurs independently of known estrogen receptors, but requires the expression of the G protein-coupled receptor homolog, GPR30. We show that 17beta-estradiol activates Erk-1/-2 not only in MCF-7 cells, which express both estrogen receptor alpha (ER alpha) and ER beta, but also in SKBR3 breast cancer cells, which fail to express either receptor. Immunoblot analysis using GPR30 peptide antibodies showed that this estrogen response was associated with the presence of GPR30 protein in these cells. MDA-MB-231 breast cancer cells (ER alpha-, ER beta+) are GPR30 deficient and insensitive to Erk-1/-2 activation by 17beta-estradiol. Transfection of MDA-MB-231 cells with a GPR30 complementary DNA resulted in overexpression of GPR30 protein and conversion to an estrogen-responsive phenotype. In addition, GPR30-dependent Erk-1/-2 activation was triggered by ER antagonists, including ICI 182,780, yet not by 17alpha-estradiol or progesterone. Consistent with acting through a G protein-coupled receptor, estradiol signaling to Erk-1/-2 occurred via a Gbetagamma-dependent, pertussis toxin-sensitive pathway that required Src-related tyrosine kinase activity and tyrosine phosphorylation of tyrosine 317 of the Shc adapter protein. Reinforcing this idea, estradiol signaling to Erk-1/-2 was dependent upon trans-activation of the epidermal growth factor (EGF) receptor via release of heparan-bound EGF (HB-EGF). Estradiol signaling to Erk-1/-2 could be blocked by: 1) inhibiting EGF-receptor tyrosine kinase activity, 2) neutralizing HB-EGF with antibodies, or 3) down-modulating HB-EGF from the cell surface with the diphtheria toxin mutant, CRM-197. Our data imply that ER-negative breast tumors that continue to express GPR30 may use estrogen to drive growth factor-dependent cellular responses.

Neurologic emergencies in the cancer patient

Neurologic complications of cancer and its therapy are varied and common, but there are few true neurologic emergencies. However, when a neurologic emergency does occur, rapid diagnosis and treatment can preserve neurologic function and, in some circumstances, save a life. Epidural spinal cord compression, raised intracranial pressure (ICP), status epilepticus, and intracerebral hemorrhage (ICH) are the most common neurologic emergencies in the cancer patient. This chapter details the clinical features, possible etiologies, diagnostic tests, and treatment options for each of these complications.

The Directional Dependence of Water Penetration into Langmuir-Blodgett Multilayers

The relationship between the mass uptake and the swelling of arachidic acid Langmuir-Blodgett (LB) films exposed to water vapor was investigated. Combining sorption data from the quartz crystal microbalance with swelling data from the surface forces apparatus (SFA), it was found that films exposed to water vapor ( approximately 75% RH) absorb 0.22 moles water/mole LB film with an associated swelling of 0.2 Å/film layer. This degree of film swelling is less than that predicted if the water taken up exhibits the molar volume of bulk liquid water. The configuration of the films in the SFA, where they are trapped between impermeable surfaces, makes possible the measurement of the lateral diffusion coefficient of water in these layered materials. This was found to be 1.5 x 10(-10) cm(2)/s, which is at least 100 times faster than diffusion normal to the layers as measured with the microbalance. Copyright 1999 Academic Press.

Maximal migration of human smooth muscle cells on fibronectin and type IV collagen occurs at an intermediate attachment strength

Although a biphasic dependence of cell migration speed on cell-substratum adhesiveness has been predicted theoretically, experimental data directly demonstrating a relationship between these two phenomena have been lacking. To determine whether an optimal strength of cell-substratum adhesive interactions exists for cell migration, we measured quantitatively both the initial attachment strength and migration speed of human smooth muscle cells (HSMCs) on a range of surface concentrations of fibronectin (Fn) and type IV collagen (CnIV). Initial attachment strength was measured in order to characterize short time-scale cell-substratum interactions, which may be representative of dynamic interactions involved in cell migration. The critical fluid shear stress for cell detachment, determined in a radial-flow detachment assay, increased linearly with the surface concentrations of adsorbed Fn and CnIV. The detachment stress required for cells on Fn, 3.6 +/- 0.2 x 10(-3) mu dynes/absorbed molecule, was much greater than that on CnIV, 5.0 +/- 1.4 x 10(-5) mu dynes/absorbed molecule. Time-lapse videomicroscopy of individual cell movement paths showed that the migration behavior of HSMCs on these substrates varied with the absorbed concentration of each matrix protein, exhibiting biphasic dependence. Cell speed reached a maximum at intermediate concentrations of both proteins, with optimal concentrations for migration at 1 x 10(3) molecules/micron2 and 1 x 10(4) molecules/micron2 on Fn and CnIV, respectively. These optimal protein concentrations represent optimal initial attachment strengths corresponding to detachment shear stresses of 3.8 mu dyne/micron2 on Fn and 1.5 mu dyne/micron2 on CnIV. Thus, while the optimal absorbed protein concentrations for migration on Fn and CnIV differed by an order of magnitude, the optimal initial attachment strengths for migration on these two proteins were very similar. Further, the same minimum strength of initial attachment, corresponding to a detachment shear stress of approximately 1 mu dyne/micron2, was required for movement on either protein. These results suggest that initial cell-substratum attachment strength is a central variable governing cell migration speed, able to correlate observations of motility on substrata differing in adhesiveness. They also demonstrate that migration speed depends in biphasic manner on attachment strength, with maximal migration at an intermediate level of cell-substratum adhesiveness.

High mortality of domestic turkeys associated with Highlands J virus and eastern equine encephalitis virus infections

High mortality occurred in two flocks of commercial turkey hens placed in southern North Carolina in fall 1991. Daily mortality peaked at 3.19% in Flock 1 and 3.79% in Flock 2. Clinical signs included restlessness, somnolence, vocalization, and acute death. Gross lesions included atrophy of the bursa of Fabricius, thymus, and spleen, and watery intestinal contents. Microscopic changes included moderate to marked lymphocyte necrosis and depletion in the bursa, thymus, and spleen, widely scattered necrosis of pancreatic acinar cells, and mild villous atrophy and fusion in the jejunum and ileum with cuboidal to low columnar epithelial cells covering the villous tips. In Flock 1, at 27 days of age, reovirus and picornavirus particles were detected in the feces. One week later, togavirus-like particles were observed in fecal contents, and two of seven serum samples showed seroconversion to Highlands J virus. Eleven days later, five of six serum samples were positive for antibodies against Highlands J virus, with a fourfold increase in the geometric mean titer. In Flock 2, seroconversion to eastern equine encephalitis virus was observed in four of 10 serum samples 11 days after the onset of clinical signs. Based on the above observations, it is suspected that these alphaviruses were the cause of the clinical syndrome.

Stopped-flow chamber and image analysis system for quantitative characterization of bacterial population migration: Motility and chemotaxis ofEscherichia coli K12 to fucose

The directed movement of a bacterial population in response to a chemical gradient is known as bacterial chemotaxis and plays a critical role in the distribution and dynamic interaction of bacterial populations. A quantitative characterization of the chemotactic response in terms of intrinsic cell properties is necessary for making reliable predictions about the migratory behavior of bacterial populations within the environment.The design of the stopped-flow diffusion chamber (SFDC) provides a well-characterized chemical gradient and reliable method for measuring bacterial migration behavior. During flow through the chamber a step change in the chemical concentration is imposed on a uniform suspension of bacteria. Once flow is stopped a transient chemical gradient forms due to diffusion; bacteria respond by forming a band of high cell density that travels toward higher concentrations of the attractant. Sequential observations of bacterial spatial distributions over a period of about ten minutes are recorded on photomicrographs. Computer-aided image analysis of the photographic negatives converts light-scattering information to a digital representation of the bacterial density profiles. A mathematical model is used to quantitatively characterize these observations in terms of intrinsic cell parameters: a chemotactic sensitivity coefficient, χ0, from the aggregate cell density accumulated in the band and a random motility coefficient, μ0, from population dispersion in the absence of a chemical gradient.Using the SFDC assay and an individual cell-based mathematical model we successfully determined values for both of these population parameters forEscherichia coli K12 responding to fucose. The values we obtained were μ0=1.1 ± 0.4 x 10(-5) cm(2)/sec and χ0=8 ± 3 x 10(-5) cm(2)/sec. These parameters will be useful for predicting population behavior in application systems such as biofilm development, population dynamics of genetically-engineered bacteria released into the environment, and in situ bioremediation technologies.

Skeletal lesions associated with a naturally occurring poult enteritis

One-day-old poults were placed on contaminated litter on which poults previously had developed an enteric disease characterized by diarrhea, increased mortality, and stunting. These exposed birds were examined for clinical signs and pathologic changes in bone and parathyroid glands compared with controls. Intestinal and fecal samples were examined for potential pathogens. Exposed poults varied in size as early as day 8 and had significantly decreased weight gains and reduced shank lengths on days 8, 12, 16, and 21. The proximal tibial growth plate was narrowed. The mineralized hypertrophy zone was decreased in length and contained multiple non-mineralized bands on days 8, 12, 16, and 21. Metaphyseal trabeculae were reduced in amount on days 16 and 21. Parathyroid glands were hyperplastic on days 16 and 21. The bone and parathyroid gland lesions indicated that mineral homeostasis was being maintained at the expense of the skeleton during the enteric disease. A specific etiology for the enteric disease was not determined. Cryptosporidium, rotavirus, paramyxovirus, and Salmonella were identified in the exposed poults, and paramyxovirus and Salmonella were identified in the controls.

Receptor-mediated cell attachment and detachment kinetics. II. Experimental model studies with the radial-flow detachment assay

Quantitative information regarding the kinetics of receptor-mediated cell adhesion to a ligand-coated surface are crucial for understanding the role of certain key parameters in many physiological and biotechnology-related processes. Here, we use the probabilistic attachment and detachment models developed in the preceding paper to interpret transient data from well-defined experiments. These data are obtained with a simple model cell system that consists of receptor-coated latex beads (prototype cells) and a Radial-Flow Detachment Assay (RFDA) using a ligand-coated glass disc. The receptors and ligands used in this work are complementary antibodies. The beads enable us to examine transient behavior with particles that possess fairly uniform properties that can be varied systematically, and the RFDA is designed for direct observation of adhesion to the ligand-coated glass surface over a range of shear stresses. Our experiments focus on the effects of surface shear stress, receptor density, and ligand density. These data provide a crucial test of the probabilistic framework. We show that these data can be explained with the probabilistic analyses, whereas they cannot be readily interpreted on the basis of a deterministic analysis. In addition, we examine transient data on cell adhesion reported from other assays, demonstrating the consistency of these data with the predictions of the probabilistic models.

Receptor-mediated cell attachment and detachment kinetics. I. Probabilistic model and analysis

The kinetics of receptor-mediated cell adhesion to a ligand-coated surface play a key role in many physiological and biotechnology-related processes. We present a probabilistic model of receptor-ligand bond formation between a cell and surface to describe the probability of adhesion in a fluid shear field. Our model extends the deterministic model of Hammer and Lauffenburger (Hammer, D.A., and D.A. Lauffenburger. 1987. Biophys. J. 52:475-487) to a probabilistic framework, in which we calculate the probability that a certain number of bonds between a cell and surface exists at any given time. The probabilistic framework is used to account for deviations from ideal, deterministic behavior, inherent in chemical reactions involving relatively small numbers of reacting molecules. Two situations are investigated: first, cell attachment in the absence of fluid stress; and, second, cell detachment in the presence of fluid stress. In the attachment case, we examine the expected variance in bond formation as a function of attachment time; this also provides an initial condition for the detachment case. Focusing then on detachment, we predict transient behavior as a function of key system parameters, such as the distractive fluid force, the receptor-ligand bond affinity and rate constants, and the receptor and ligand densities. We compare the predictions of the probabilistic model with those of a deterministic model, and show how a deterministic approach can yield some inaccurate results; e.g., it cannot account for temporally continuous cell attach mentor detachment, it can underestimate the time needed for cell attachment, it can overestimate the time required for cell detachment for a given level of force, and it can overestimate the force necessary for cell detachment.

Receptor-mediated adhesion phenomena. Model studies with the Radical-Flow Detachment Assay

Receptor-mediated cell adhesion phenomena play a vital role in many physiological and biotechnology-related processes. To investigate the physical and chemical factors that influence the cell/surface interaction, we have used a radial flow device, a so-called Radial-Flow Detachment Assay (RFDA). The RFDA allows us to make direct observations of the detachment process under specified experimental conditions. In results reported here, we have studied the detachment of receptor-coated latex beads (prototype cells) from ligand-coated glass surfaces. The receptors and ligands used in this work are complementary antibodies. The beads enable us to examine several aspects of the adhesion process with particles having uniform properties that can be varied systematically. Advantages of the RFDA are many, especially direct observation of cell detachment over a range of shear stresses with quantitative measurement of the adhesive force. We focus our studies on the effects of ligand and receptor densities, along with the influence of pH and ionic strength of the medium. These data are analyzed with a mathematical model based on the theoretical framework of Bell, G. I. (1978. Science [Wash. DC]. 200:618-627) and Hammer, D. A. and D. A. Lauffenburger (1987. Biophys. J. 52:475-487). We demonstrate experimental validation of a theoretical expression for the critical shear stress for particle detachment, and show that it is consistent with reasonable estimates for the receptor-ligand bond affinity.

Permeation of inert gases through human skin: modeling the effect of skin blood flow

We present an analytic method for determining the effects of skin perfusion--vasculature and flow rates--on the flux of inert gases through human skin. We systematically specify the underlying blood flow and examine the resulting fluxes of several gases, allowing for the appropriate tissue resistances. For physiological flows, the stratum corneum has an effect equivalent to a series resistance. Helium flux at low total flow depends primarily on subdermal perfusion, but at higher flow, middermal and subpapillary effects become important. The fluxes of less permeable gases, such as argon and xenon, depend on middermal and subpapillary flow at lower total flows. From any single measurement of gas flux, it is difficult to establish an unambiguous value for the underlying blood flow, but the simultaneous measurement of different gases narrows the range of plausible conditions.