Patricia Louise Coletta

Changes in plasma chemokine C-C motif ligand 2 levels during treatment with eicosapentaenoic acid predict outcome in patients undergoing surgery for colorectal cancer liver metastasis.

The mechanism of the anti-colorectal cancer (CRC) activity of the omega-3 fatty acid eicosapentaenoic acid (EPA) is not understood. We tested the hypothesis that EPA reduces expression of chemokine C-C motif ligand 2 (CCL2), a pro-inflammatory chemokine with known roles in metastasis. We measured CCL2 in clinical samples from a randomized trial of EPA in patients undergoing liver surgery for CRC liver metastasis (LM) and preclinical models. Genome-wide transcriptional profiling of tumors from EPA-treated patients was performed. EPA decreased CCL2 synthesis by CRC cells in a dose-dependent manner. CCL2 was localized to malignant epithelial cells in human CRCLM. EPA did not reduce CCL2 content in human or mouse tumors compare to control. However, EPA treatment was associated with decreased plasma CCL2 levels compared with controls (P=0.04). Reduction in plasma CCL2 following EPA treatment predicted improved disease-free survival (HR 0.32; P=0.003). Lack of ‘CCL2 response’ was associated with a specific CRCLM gene expression signature. In conclusion, reduction in plasma CCL2 in patients with CRCLM treated with EPA predicts better clinical outcome and a specific tumor gene expression profile. Further work is needed to validate CCL2 as a therapeutic response biomarker for omega-3 fatty acid treatment of CRC patients.

Developing Hollow-Channel Gold Nanoflowers as Trimodal Intracellular Nanoprobes

Gold nanoparticles-enabled intracellular surface-enhanced Raman spectroscopy (SERS) provides a sensitive and promising technique for single cell analysis. Compared with spherical gold nanoparticles, gold nanoflowers, i.e., flower-shaped gold nanostructures, can produce a stronger SERS signal. Current exploration of gold nanoflowers for intracellular SERS has been considerably limited by the difficulties in preparation, as well as background signal and cytotoxicity arising from the surfactant capping layer. Recently, we have developed a facile and surfactant-free method for fabricating hollow-channel gold nanoflowers (HAuNFs) with great single-particle SERS activity. In this paper, we investigate the cellular uptake and cytotoxicity of our HAuNFs using a RAW 264.7 macrophage cell line, and have observed effective cellular internalization and low cytotoxicity. We have further engineered our HAuNFs into SERS-active tags, and demonstrated the functionality of the obtained tags as trimodal nanoprobes for dark-field and fluorescence microscopy imaging, together with intracellular SERS.

Abstract 1572: Characterising the tumor vasculature in vivo in mouse models of colorectal cancer using contrast enhanced high-frequency ultrasound

Angiogenesis is essential for tumours to grow beyond a few millimetres in size and to metastasise, making it an attractive target for both cancer imaging and therapeutic intervention. Although microvessel density (MVD) is routinely used to assess tumour vascularity in fixed tissue, few techniques are currently available for imaging and quantitating tumour vasculature parameters in vivo. High-frequency ultrasound (HFUS) allows high resolution, non-invasive longitudinal imaging of tumours in vivo. Incorporation of microbubble contrast agent into imaging protocols allows visualisation of the vasculature, determination of relative blood flow and perfusion, and the ability to directly target and quantify molecular biomarkers of disease in vivo. We have been investigating in vivo tumour blood flow and vascularity in the growth of human colorectal cancer (CRC) cell xenografts. CD1 Nu/Nu mice implanted with SW480 cell xenografts were used to investigate the relationship between tumour growth and different vascular parameters obtained by contrast enhanced (CE) HFUS. Mice were imaged at day 21 and day 27 of tumour growth using the VisualSonics Vevo 770 system. A single bolus of microbubbles was injected via a syringe driver into the tail vein during 2D CE HFUS imaging, with the wash-in data loops captured prior to 3D CE HFUS imaging, and tissue samples collected for histology and immunohistochemistry. Time intensity curves were generated post-acquisition and used to determine perfusion kinetics and vascular data. A number of strongly significant correlations were observed relating in vivo and histological tumour characteristics with relative blood flow and total vascularity. These included the size of the tumour, tumour growth and the total vascular space. This study shows that CE HFUS is a powerful qualitative and quantitative tool for the analysis of tumour angiogenesis in vivo. It provides a relatively non-invasive method to monitor tumour blood flow and vascularity in longitudinal studies thus allowing effects on angiogenesis due to therapeutic intervention to be monitored. We are currently developing this technique for use with autochthonous colorectal cancer models. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1572. doi:10.1158/1538-7445.AM2011-1572