Targeted Treatment against Cancer Stem Cells in Colorectal Cancer.

The cancer stem cell (SC) theory proposes that a population of SCs serves as the driving force behind fundamental tumor processes, including metastasis, recurrence, and resistance to therapy. The standard of care for patients with stage III and high-risk stage II colorectal cancer (CRC) includes surgery and adjuvant chemotherapy. Fluoropyrimidines and their combination with oxaliplatin increased the cure rates, being able to eradicate the occult metastatic SC in a fraction of patients. The treatment for unresectable metastatic CRC is based on chemotherapy, antibodies to VEGF and EGFR, and tyrosine-kinase inhibitors. Immunotherapy is used in MSI-H tumors. Currently used drugs target dividing cells and, while often effective at debulking tumor mass, these agents have largely failed to cure metastatic disease. SCs are generated either due to genetic and epigenetic alterations in stem/progenitor cells or to the dedifferentiation of somatic cells where diverse signaling pathways such as Wnt/ß-catenin, Hedgehog, Notch, TGF-ß/SMAD, PI3K/Akt/mTOR, NF-κB, JAK/STAT, DNA damage response, and Hippo-YAP play a key role. Anti-neoplastic treatments could be improved by elimination of SCs, becoming an attractive target for the design of novel agents. Here, we present a review of clinical trials assessing the efficacy of targeted treatment focusing on these pathways in CRC.

Effectiveness, safety, and prognostic factors of trifluridine/tipiracil for the treatment of patients with metastatic colorectal cancer in routine clinical practice.

Background: The combination of trifluridine and tipiracil is indicated in patients with metastatic colorectal cancer previously treated or non-candidates to chemotherapy and biological therapies. This study in routine clinical practice aimed to describe the effectiveness and safety of trifluridine and tipiracil and identify prognostic factors in patients with metastatic colorectal cancer in Spain. Methods: This analysis was a retrospective, observational, multicenter study that included patients aged ≥18 years who had received treatment with trifluridine/tipiracil for metastatic colorectal cancer in third- or subsequent lines. Results: Overall, 294 were evaluated. Trifluridine/tipiracilmedian (minimum, maximum) treatment duration was 3.5 (1.0-29.0) months, and 128 (43.5%) patients received subsequent treatments. One hundred (34%) patients showed disease control rate, and the median progression-free survival and overall survival from trifluridine/tipiracil treatment onset were 3.7 and 7.5 months, respectively. The most frequently reported adverse events were asthenia (all grades, 57.9%) and neutropenia (all grades, 51.3%). A 39.1% and 4.4% of the participants had a dose reduction and a treatment interruption due to toxicity. Patients with age ≥65 years, low tumor burden, ≤2 metastasis sites, treatment dose reduction, neutropenia, and ≥6 cycles, had significantly higher overall survival, progression-free survival, and response rate. Conclusions: This real-life study indicates that trifluridine/tipiracil shows effectiveness and safety in treating patients with metastatic colorectal cancer. The results show a profile of metastatic colorectal cancer patients with previously unknown prognostic factors who have a more significant benefit from treatment with trifluridine/tipiracil in routine clinical practice.

PAI1 is a Marker of Bad Prognosis in Rectal Cancer but Predicts a Better Response to Treatment with PIM Inhibitor AZD1208.

Colorectal cancer (CRC) is the third most common cancer worldwide. The standard treatment in locally advanced rectal cancer is preoperative radiation alone or in combination with chemotherapy, followed by adjuvant chemotherapy. Rectal cancer is highly lethal, with only 20% of patients showing a complete remission (by RECIST) after standard treatment, although they commonly show local or systemic relapse likely due to its late detection and high chemotherapy resistance, among other reasons. Here, we explored the role of PAI1 (Serpin E1) in rectal cancer through the analyses of public patient databases, our own cohort of locally advanced rectal cancer patients and a panel of CRC cell lines. We showed that PAI1 expression is upregulated in rectal tumors, which is associated with decreased overall survival and increased metastasis and invasion in advanced rectal tumors. Accordingly, PAI1 expression is correlated with the expression of (Epithelial-to-Mesenchymal Transition) EMT-associated genes and genes encoding drug targets, including the tyrosine kinases PDGFRb, PDGFRa and FYN, the serine/threonine kinase PIM1 and BRAF. In addition, we demonstrate that cells expressing PAI1 protein are more sensitive to the PIM inhibitor AZD1208, suggesting that PAI1 could be used to predict response to treatment with PIM inhibitors and to complement radiotherapy in rectal tumors.

The safety of trifluridine and tipiracil for the treatment of metastatic colorectal cancer.

INTRODUCTION: TAS102 is an oral thymidine-based nucleoside analog that has been approved for the treatment of patients with metastatic colorectal cancer (mCRC) previously treated with, or not candidates for, available therapies including fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapies, anti-vascular endothelial growth factor (VEGF) agents and, if RAS wild-type, anti-epidermal growth factor receptor (EGFR) therapy. The pivotal RECOURSE phase III trial demonstrated a significant improvement in disease control rate, progression-free survival (PFS), and overall survival (OS) as compared with placebo in patients with refractory mCRC. Areas covered: This manuscript aims to review the clinical development of TAS102 in CRC, with a particular focus on safety, and to provide some perspective regarding its role in clinical practice. A literature search was conducted of MEDLINE and EMBASE databases for published studies (January 2004-December 2016) using the search terms TAS102, trifluridine-tipiracil, metastatic or advanced CRC, clinical trial, toxicity, safety, pharmacology, pharmacokinetics, and therapy. Expert opinion: TAS102 significantly improves survival of patients with refractory mCRC and has manageable toxicity. An expanding role in the treatment of CRC is expected for TAS102 in the near future, as its favorable safety profile makes TAS102 a suitable drug to be combined with other cytotoxic and targeted agents.

Prognostic relevance of Src activation in stage II-III colon cancer.

Src belongs to a family of cytoplasmic tyrosine kinases that play a key role in tumor initiation and progression. Src activation has been associated with a more aggressive neoplastic phenotype and induces resistance to platinum agents in preclinical models. The aim of our study was to assess the prognostic and/or predictive value of Src activation in patients with stage II-III colon cancer. pSrc expression was assessed in paraffin-embedded tumor samples by immunohistochemistry (phospho-Y418, ab4816; Abcam). Cases were classified by staining intensity in 4 categories: no staining (0), weak (1+), moderate (2+), and intense (3+) staining. A total of 487 patients were evaluated (240 stage II, 247 stage III), of whom 298 (61%) had received adjuvant chemotherapy. Staining was absent in 78 (16%), weak in 262 (54%), moderate in 103 (21%), and intense in 44 (9%). High pSrc expression was significantly associated with decreased 5-year disease-free survival (39% versus 63% for patients with high versus low pSrc expression; hazard ratio, 0.56; P=.005) and overall survival (58% versus 74%; hazard ratio, 0.55; P=.02). Multivariate analysis confirmed pSrc expression as a significant prognostic factor both for disease-free survival and overall survival, independent of age, sex, tumor stage, bowel obstruction/perforation, or adjuvant chemotherapy. These findings illustrate the relevance of Src activation in colon cancer biology, conferring a poor prognosis to patients with early stage colon cancer regardless of adjuvant chemotherapy. Our findings may help improve prognostic stratification of patients for clinical decisions and open new avenues for potential pharmacologic manipulation that may eventually improve patients' outcomes.

Gene expression profile predictive of response to chemotherapy in metastatic colorectal cancer.

Fluoropyrimidine-based chemotherapy (CT) has been the mainstay of care of metastatic colorectal cancer (mCRC) for years. Response rates are only observed, however, in about half of treated patients, and there are no reliable tools to prospectively identify patients more likely to benefit from therapy. The purpose of our study was to identify a gene expression profile predictive of CT response in mCRC. Whole genome expression analyses (Affymetrix GeneChip HG-U133 Plus 2.0) were performed in fresh frozen tumor samples of 37 mCRC patients (training cohort). Differential gene expression profiles among the two study conditions (responders versus non-responders) were assessed using supervised class prediction algorithms. A set of 161 differentially expressed genes in responders (23 patients; 62%) versus non-responders (14 patients; 38%) was selected for further assessment and validation by RT-qPCR (TaqMan Low Density Arrays (TLDA) 7900 HT Micro Fluidic Cards) in an independent multi-institutional cohort (53 mCRC patients). Seven of these genes were confirmed as significant predictors of response. Patients with a favorable predictive signature had significantly greater response rate (58% vs. 13%, p = 0.024), progression-free survival (61% vs. 13% at 1 year, HR = 0.32, p = 0.009) and overall survival (32 vs. 16 months, HR = 0.21, p = 0.003) than patients with an unfavorable gene signature. This is the first study to validate a gene-expression profile predictive of response to CT in mCRC patients. Larger and prospective confirmatory studies are required, however, in order to successfully provide oncologists with adequate tools to optimize treatment selection in routine clinical practice.