Imaging in Colorectal Cancer: Progress and Challenges for the Clinicians

PrediCTC, liquid biopsy in precision oncology: a technology transfer experience in the Spanish health system

PURPOSE

Management of metastatic disease in oncology includes monitoring of therapy response principally by imaging techniques like CT scan. In addition to some limitations, the irruption of liquid biopsy and its application in personalized medicine has encouraged the development of more efficient technologies for prognosis and follow-up of patients in advanced disease.

METHODS

PrediCTC constitutes a panel of genes for the assessment of circulating tumor cells (CTC) in metastatic colorectal cancer patients, with demonstrated improved efficiency compared to CT scan for the evaluation of early therapy response in a multicenter prospective study. In this work, we designed and developed a technology transfer strategy to define the market opportunity for an eventual implementation of PrediCTC in the clinical practice.

RESULTS

This included the definition of the regulatory framework, the analysis of the regulatory roadmap needed for CE mark, a benchmarking study, the design of a product development strategy, a revision of intellectual property, a cost-effectiveness study and an expert panel consultation.

CONCLUSION

The definition and analysis of an appropriate technology transfer strategy and the correct balance among regulatory, financial and technical determinants are critical for the transformation of a promising technology into a viable technology, and for the decision of implementing liquid biopsy in the monitoring of therapy response in advanced disease.

miR‑647 and miR‑1914 promote cancer progression equivalently by downregulating nuclear factor IX in colorectal cancer

MicroRNAs (miRNAs/miRs) have been investigated as diagnostic and prognostic biomarkers for cancer; however, the significance of miRNAs in colorectal cancer (CRC) remains to be elucidated. The aim of the present study was to determine the genetic profiles of CRC tissue, and screen for miRNAs implicated in CRC cell proliferation and migration. RNA sequencing of 10 paired specimens was performed to for screen genes that were upregulated or downregulated in CRC. miRNA expression in CRC specimens and cell lines was confirmed using qPCR analysis. The significance of indicated miRNAs in CRC cell proliferation and migration was evaluated using MTT and scratch wound-healing assays. Online computational prediction, isobaric tags for relative and absolute quantification analysis and a luciferase reporter assay were applied to determine candidate targeted genes for the miRNAs. RNA-seq data revealed miR-1914 as the most prominent miRNA in CRC specimens. qPCR analysis also suggested that the expression of miR-1914, as well as its counterpart miR-647 were elevated in CRC specimens and cell lines. Suppression of miR-647/1914 using small interfering RNAs inhibited CRC SW480 and SW620 cell proliferation, and migration. Nuclear factor I/X (NFIX) was demonstrated to be a candidate for miR-647/1914 and mediated the oncogenic activity of miR-647/1914. In all, miR-647 and miR-1914 were demonstrated to promote the proliferation and migration of CRC cells by directly targeting NFIX. Therapeutic delivery of siRNAs targeting miR-647/1914 and overexpression of NFIX may be feasible approaches for CRC treatment.

Development of Halofluorochromic Polymer Nanoassemblies for the Potential Detection of Liver Metastatic Colorectal Cancer Tumors Using Experimental and Computational Approaches

PURPOSE

To develop polymer nanoassemblies (PNAs) modified with halofluorochromic dyes to allow for the detection of liver metastatic colorectal cancer (CRC) to improve therapeutic outcomes.

METHODS

We combine experimental and computational approaches to evaluate macroscopic and microscopic PNA distributions in patient-derived xenograft primary and orthotropic liver metastatic CRC tumors. Halofluorochromic and non-halofluorochromic PNAs (hfPNAs and n-hfPNAs) were prepared from poly(ethylene glycol), fluorescent dyes (Nile blue, Alexa546, and IR820), and hydrophobic groups (palmitate), all of which were covalently tethered to a cationic polymer scaffold [poly(ethylene imine) or poly(lysine)] forming particles with an average diameter < 30 nm.

RESULTS

Dye-conjugated PNAs showed no aggregation under opsonizing conditions for 24 h and displayed low tissue diffusion and cellular uptake. Both hfPNAs and n-hfPNAs accumulated in primary and liver metastatic CRC tumors within 12 h post intravenous injection. In comparison to n-hfPNAs, hfPNAs fluoresced strongly only in the acidic tumor microenvironment (pH < 7.0) and distinguished small metastatic CRC tumors from healthy liver stroma. Computational simulations revealed that PNAs would steadily accumulate mainly in acidic (hypoxic) interstitium of metastatic tumors, independently of the vascularization degree of the tissue surrounding the lesions.

CONCLUSION

The combined experimental and computational data confirms that hfPNAs detecting acidic tumor tissue can be used to identify small liver metastatic CRC tumors with improved accuracy.

Predicting Outcome and Therapy Response in mCRC Patients Using an Indirect Method for CTCs Detection by a Multigene Expression Panel: A Multicentric Prospective Validation Study

Colorectal cancer (CRC) is one of the major causes of cancer-related deaths. Early detection of tumor relapse is crucial for determining the most appropriate therapeutic management. In clinical practice, computed tomography (CT) is routinely used, but small tumor changes are difficult to visualize, and reliable blood-based prognostic and monitoring biomarkers are urgently needed. The aim of this study was to prospectively validate a gene expression panel (composed of GAPDH, VIL1, CLU, TIMP1, TLN1, LOXL3 and ZEB2) for detecting circulating tumor cells (CTCs) as prognostic and predictive tool in blood samples from 94 metastatic CRC (mCRC) patients. Patients with higher gene panel expression before treatment had a reduced progression-free survival (PFS) and overall-survival (OS) rates compared with patients with low expression (p = 0.003 and p ≤ 0.001, respectively). Patients with increased expression of CTCs markers during treatment presented PFS and OS times of 8.95 and 11.74 months, respectively, compared with 14.41 and 24.7 for patients presenting decreased expression (PFS; p = 0.020; OS; p ≤ 0.001). Patients classified as non-responders by CTCs with treatment, but classified as responders by CT scan, showed significantly shorter survival times (PFS: 8.53 vs. 11.70; OS: 10.37 vs. 24.13; months). In conclusion, our CTCs detection panel demonstrated efficacy for early treatment response assessment in mCRC patients, and with increased reliability compared to CT scan.

Guanylate cyclase C as a target for prevention, detection, and therapy in colorectal cancer

INTRODUCTION

Colorectal cancer remains the second leading cause of cancer death in the United States, and new strategies to prevent, detect, and treat the disease are needed. The receptor, guanylate cyclase C (GUCY2C), a tumor suppressor expressed by the intestinal epithelium, has emerged as a promising target. Areas covered: This review outlines the role of GUCY2C in tumorigenesis, and steps to translate GUCY2C-targeting schemes to the clinic. Endogenous GUCY2C-activating ligands disappear early in tumorigenesis, silencing its signaling axis and enabling transformation. Pre-clinical models support GUCY2C ligand supplementation as a novel disease prevention paradigm. With the recent FDA approval of the GUCY2C ligand, linaclotide, and two more synthetic ligands in the pipeline, this strategy can be tested in human trials. In addition to primary tumor prevention, we also review immunotherapies targeting GUCY2C expressed by metastatic lesions, and platforms using GUCY2C as a biomarker for detection and patient staging. Expert commentary: Results of the first GUCY2C targeting schemes in patients will become available in the coming years. The identification of GUCY2C ligand loss as a requirement for colorectal tumorigenesis has the potential to change the treatment paradigm from an irreversible disease of genetic mutation, to a treatable disease of ligand insufficiency.