Biomarkers of Angiogenesis in Colorectal Cancer

Advances on Senescence-associated secretory phenotype regulated by circular RNAs in tumors

The components that comprise the senescence-associated secretory phenotype (SASP) include growth factors, proteases, chemokines, cytokines, and bioactive lipids. It drives secondary aging and disrupts tissue homeostasis, ultimately leading to tissue repair and regeneration loss. It has a two-way regulatory effect on tumor cells, resisting cancer occurrence and promoting its progression. A category of single-stranded circular non-coding RNA molecules known as circular RNAs (circRNAs) carries out a series of cellular activities, including sequestering miRNAs and modulating gene editing and expression. Research has demonstrated that a large number of circRNAs exhibit aberrant expression in pathological settings, and play a part in the onset and progress of cancer via modulating SASP factors. However, the research related to SASP and circRNAs in tumors is still in its infancy at this stage. This review centers on the bidirectional modulation of SASP and the role of circRNAs in regulating SASP factors across different types of tumors. The aim is to present novel perspectives for the diagnosis and therapeutic management of malignancies.

Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer

BACKGROUND

The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC).

OBJECTIVE

This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC.

PATIENTS AND METHODS

The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed.

RESULTS

Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS.

CONCLUSION

Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted.

CLINICAL TRIAL REGISTRATION NUMBER

jRCTs031180122.

Exosomal circCOL1A1 promotes angiogenesis via recruiting EIF4A3 protein and activating Smad2/3 pathway in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third frequently diagnosed cancer with high incidence and mortality rate worldwide. Our previous report has demonstrated that circCOL1A1 (hsa_circ_0044556) functions as an oncogene in CRC, and Gene Ontology (GO) analysis has also revealed the strong association between circCOL1A1 and angiogenesis. However, the mechanism of circCOL1A1 or exosomal circCOL1A1 in CRC angiogenesis remains elusive.

METHODS

Purified exosomes from CRC cells were characterized by nanoparticle tracking analyzing, electron microscopy and western blot. qRT-PCR, immunohistochemistry or western blot were employed to test the expression of circCOL1A1, EIF4A3, Smad pathway and angiogenic markers. Cell proliferation of HUVECs was monitored by CCK-8 assay. The migratory and angiogenic capabilities of HUVECs were detected by wound healing and tube formation assay, respectively. Bioinformatics analysis, RNA immunoprecipitation (RIP), RNA pull-down and FISH assays were used to detect the interactions among circCOL1A1, EIF4A3 and Smad2/3 mRNA. The in vitro findings were verified in xenograft model.

RESULTS

CRC cell-derived exosomal circCOL1A1 promoted angiogenesis of HUVECs via recruiting EIF4A3. EIF4A3 was elevated in CRC tissues, and it stimulated angiogenesis of HUVECs through directly binding and stabilizing Smad2/3 mRNA. Moreover, exosomal circCOL1A1 promoted angiogenesis via inducing Smad2/3 signaling pathway in vitro, and it also accelerated tumor growth and angiogenesis in vivo.

CONCLUSION

CRC cell-derived exosomal circCOL1A1 promoted angiogenesis via recruiting EIF4A3 and activating Smad2/3 signaling.

The emergence of RAS mutations in patients with RAS wild-type mCRC receiving cetuximab as first-line treatment: a noninterventional, uncontrolled multicenter study

ABSRTACT

BACKGROUND: Patients treated with anti-epidermal growth factor receptor (anti-EGFR) will ultimately develop acquired resistance promoted by clonal selection, mainly the emergence of mutations in the MAPK pathway (mostly RAS mutations). Baseline assessment of RAS mutations in the blood of patients correlates well with RAS tumour tissue testing and is currently an alternative option in routine clinical practice to guide first-line therapy. The aim of this study was the prevalence of acquired genomic alterations detected in the auxiliary tool of ctDNA testing and investigated the role of RAS ctDNA status for detecting tumour response and predicting benefit to anti-EGFR therapy.

METHODS

Only patients with concordant wild-type formalin-fixed, paraffin-embedded (FFPE) tumour tissue and baseline ctDNA RAS wild-type were included. RAS mutations in plasma were evaluated using MassARRAY platform. Blood samples were collected at baseline, every 3 months during first-line treatment, and at disease progression. The primary endpoint was the detection rate of RAS mutations during cetuximab treatment. The correlation between response and survival outcomes and the emergence of circulating RAS mutations was also analysed.

RESULTS

The detection rate of RAS mutations during treatment was 9.3% (10/108). RAS mutations detection occurred a median of 3 months prior to radiologic documentation. The subgroup of patients with RAS mutations exhibited significantly inferior progression-free survival and overall survival (P = 0.002 and 0.027, respectively) but the baseline characteristics, response rates, disease control rates, and metastatectomy were not significant (all P > 0.05).

CONCLUSIONS

We demonstrated that RAS ctDNA status might be a valuable biomarker for detecting early tumour response and predicting benefit to anti-EGFR therapy.

CLINICAL TRIAL REGISTRATION

NCT03401957 (January 17, 2018).

Dysregulated Forkhead Box (FOX) Genes Association with Survival Prognosis, Anti-tumor Immunity, and Key Targeting Drugs in Colon Adenocarcinoma

BACKGROUND

Several studies have revealed that the aberrant expressions of forkhead box (FOX) genes are associated with carcinogenesis. However, the crucial biological functions of the FOX gene in colon adenocarcinoma (COAD) remain unknown.

METHODS

The TCGA-COAD dataset (n=328) was utilized for determining the deregulated FOX genes and their association with functional enrichment, protein-protein interaction (PPI), survival prognosis, anti-tumor immunity, cancer-associated pathways, and biological processes in COAD. In addition, we used GSE166427 (GPL13667) as a validation cohort (n=196). Molecular docking studies were applied to perform the drug interactions.

RESULTS

The FOX genes are deregulated in the COAD (Log2 FC>0.50, P<0.05), and the PPI network of FOX members is substantially related to the enrichment of cancerous signaling, immune responses, and cellular development (FDR<0.05). A worse prognosis for overall survival in COAD individuals is connected with the subgroup of FOX transcripts (P≤0.05). FOXD4, FOXH1, and FOXS1 were identified as predictive variables in the univariate and multivariate Cox regression models (P≤0.05). FOXH1 and FOXS1 are substantially linked to the deregulated immunity in COAD (R>0.20, P<0.01). Furthermore, FOXS1 expression regulates cancer-associated pathways and biological processes (P<0.05). Moreover, FOXD4, FOXH1, and FOXS1 are genetically altered and showed diagnostic efficacy in COAD. We revealed that FOXD4, FOXH1, and FOXS1 are consistently deregulated in GSE166427 (P<0.05). Finally, molecular docking revealed that FOXH1 interacted with various drugs, including belinostat, entinostat, and panobinostat.

CONCLUSION

The FOX genes have a strong correlation with the poor prognosis for survival, tumor immunity, cancer-associated pathways, and biochemical processes that cause the pathogenesis of COAD.

CircRNA-miRNA-VEGFA: an important pathway to regulate cancer pathogenesis

Cancers, especially malignant tumors, contribute to high global mortality rates, resulting in great economic burden to society. Many factors are associated with cancer pathogenesis, including vascular endothelial growth factor-A (VEGFA) and circular RNAs (circRNA). VEGFA is a pivotal regulator of vascular development such as angiogenesis, which is an important process in cancer development. CircRNAs have covalently closed structures, making them highly stable. CircRNAs are widely distributed and participate in many physiological and pathological processes, including modulating cancer pathogenesis. CircRNAs act as transcriptional regulators of parental genes, microRNA (miRNA)/RNA binding protein (RBP) sponges, protein templates. CircRNAs mainly function via binding to miRNAs. CircRNAs have been shown to influence different diseases such as coronary artery diseases and cancers by regulating VEGFA levels via binding to miRNAs. In this paper, we explored the origin and functional pathways of VEGFA, reviewed the current understanding of circRNA properties and action mechanisms, and summarized the role of circRNAs in regulating VEGFA during cancer pathogenesis.

Pre-Surgery Inflammatory and Angiogenesis Biomarkers as Predictors of 12-Month Cancer-Related Distress: Results from the ColoCare Study

BACKGROUND

Patients with colorectal cancer commonly suffer from complex psychological distress. Elevated distress may be linked to systemic biomarkers. We investigated associations of biomarkers of inflammation and angiogenesis with cancer-related distress (CTXD) score.

METHODS

N = 315 patients (stage I-IV) from 2 centers of the ColoCare Study were included: Huntsman Cancer Institute and University of Heidelberg. Biomarkers (e.g., IL6, VEGF-A, VEGF-D) were measured in serum collected pre-surgery and 12 months thereafter. The CTXD overall score and 4 subscales were collected 12 months after surgery and dichotomized to investigate biomarkers as predictors of distress 12 months after surgery; adjusted for age, sex, body mass index, tumor stage, center, and baseline levels of biomarkers.

RESULTS

Doubling of IL6 predicted future increased risk of overall distress [odds ratio (OR), 1.20; 95% confidence interval (CI), 1.02-1.41; P = 0.03]. VEGF-A-predicted future increased risk of high family strain (VEGF-A: OR, 1.21; 95% CI, 1.01-1.44; P = 0.04) and VEGF-D was associated with medical and financial demands (OR, 1.34; 95% CI, 1.01-1.74; P = 0.03).

CONCLUSIONS

This is the first study to show that systemic biomarkers are significantly associated with future CTXD score. Distress was not measured at baseline; we cannot rule out ongoing associations of inflammation and distress throughout treatment versus a direct effect of inflammation on distress. Nonetheless, these data add to evidence that biobehavioral processes interact and that systemic biomarkers are associated with cancer-related distress one year after surgery.

IMPACT

Exercise and diet interventions that lower systemic cytokine levels may impact longer-term CTXD score and improve quality of life of patients with colorectal cancer.

Progress in the relationship between P2X7R and colorectal cancer

Purinergic ligand-gated ion channel 7 receptor (P2X7R) is a nonselective cation channel of the purinergic receptor family. P2X7R is activated by adenosine triphosphate (ATP) and plays a significant role in inflammatory and autoimmune diseases by triggering cellular signal transduction. More importantly, P2X7R is abnormally expressed in many tumor cells and is involved in the progression of various tumor cells. Studies have shown that the irregular expression of P2X7R in colorectal cancer (CRC) can not only indirectly affect the occurrence and development of CRC by promoting inflammatory bowel disease but also directly affect the proliferation and metastasis of CRC cells. P2X7R plays a bidirectional role in cancer induction and inhibition by mediating complex signaling pathways in CRC, and its expression level is closely related to the overall survival of CRC patients. Therefore, P2X7R may be a biomarker and potential therapeutic target for the development and prognosis of CRC. In this paper, we review the research progress on P2X7R in CRC.

Contribution of natural killer cells in innate immunity against colorectal cancer

Natural killer cells are members of the innate immune system and promote cytotoxic activity against tumor or infected cells independently from MHC recognition. NK cells are modulated by the expression of activator/inhibitory receptors. The ratio of this activator/inhibitory receptors is responsible for the cytotoxic activity of NK cells toward the target cells. Owing to the potent anti-tumor properties of NK cells, they are considered as interesting approach in tumor treatment. Colorectal cancer (CRC) is the second most common cause of death in the world and the incidence is about 2 million new cases per year. Metastatic CRC is accompanied by a poor prognosis with less than three years of overall survival. Chemotherapy and surgery are the most adopted treatments. Besides, targeted therapy and immune checkpoint blockade are novel approach to CRC treatment. In these patients, circulating NK cells are a prognostic marker. The main target of CRC immune cell therapy is to improve the tumor cell's recognition and elimination by immune cells. Adaptive NK cell therapy is the milestone to achieve the purpose. Allogeneic NK cell therapy has been widely investigated within clinical trials. In this review, we focus on the NK related approaches including CAR NK cells, cell-based vaccines, monoclonal antibodies and immunomodulatory drugs against CRC tumoral cells.

Micro RNA 148a induces apoptosis and prevents angiogenesis with bevacizumab in colon cancer through direct inhibition of ROCK1/c-Met via HIF-1α under hypoxia

Angiogenesis and antiapoptosis effects are the major factors influencing malignancy progression. Hypoxia induces multiple mechanisms involving microRNA (miRNA) activity. Vascular endothelial growth factor (VEGF) is correlated with angiogenesis. An antiapoptotic factor, myeloid leukemia 1 (Mcl-1) is the main regulator of cell death. This study examined the role of miR-148a in inhibiting VEGF and Mcl-1 secretion by directly targeting ROCK1/c-Met by downregulating HIF-1α under hypoxia. The protein expression of ROCK1 or Met/HIF-1α/Mcl-1 in HCT116 and HT29 cells (all P < 0.05) was significantly reduced by miR-148a. The tube-formation assay revealed that miR-148a significantly suppressed angiogenesis and synergistically enhanced the effects of bevacizumab (both P < 0.05). The MTT assay revealed the inhibitory ability of miR-148a in HCT116 and HT29 cells (both P < 0.05). miR-148a and bevacizumab exerted synergistic antitumorigenic effects (P < 0.05) in an animal model. Serum miR-148a expression of metastatic colorectal cancer (mCRC) patients with a partial response was higher than that of mCRC patients with disease progression (P = 0.026). This result revealed that miR-148a downregulated HIF-1α/VEGF and Mcl-1 by directly targeting ROCK1/c-Met to decrease angiogenesis and increase the apoptosis of colon cancer cells. Furthermore, serum miR-148a levels have prognostic/predictive value in patients with mCRC receiving bevacizumab.

Antitumor effect of isoquercetin on tissue vasohibin expression and colon cancer vasculature

Tumor cells trigger angiogenesis through the expression of angiogenic factors. Vasohibins (VASHs) are a family of peptides that regulate angiogenesis. Flavonoids have antiproliferative antitumor properties; however, few studies have highlighted their antiangiogenic potential. This study evaluated the flavonoid isoquercetin (Q3G) as an antitumor compound related to colon cancer vascularization and regulation of VASH1 and 2. Mice bearing xenogeneic colon cancer (n = 15) were divided into 3 groups: Q3G-treated (gavage, daily over a week), bevacizumab-treated (intraperitoneal, single dose), or untreated animals. Tumor growth, histological characteristics, blood vessel volume, and VASH1 and 2 expressions were analyzed. Q3G impaired tumor growth and vascularization, upregulated VASH1, and downregulated VASH2 in comparison to untreated animals. Mice treated with Q3G showed approximately 65% fewer blood vessels than untreated animals and 50% fewer blood vessels than mice treated with bevacizumab. Thus, we show that Q3G has antitumor activity, impairs vascularization, and differentially modulates VASH1 and 2 expressions in colon cancer.

Interrogating the interplay of angiogenesis and immunity in metastatic colorectal cancer

Colon cancer is the third most common malignancy and the fifth most frequent cause of death from neoplastic disease worldwide. At the time of diagnosis, more than 20% of patients already have metastatic disease. In the last 20 years, the natural course of the disease has changed due to major changes in the management of metastatic disease such as the advent of novel surgical and local therapy approaches as well as the introduction of novel chemotherapy drugs and targeted agents such as anti-epidermal growth factor receptor, anti-BRAF and antiangiogenics. Angiogenesis is a complex biological process of new vessel formation from existing ones and is an integral component of tumor progression supporting cancer cells to grow, proliferate and metastasize. Many molecules are involved in this proangiogenic process, such as vascular endothelial growth factor and its receptors on endothelial cells. A well-standardized methodology that is applied to assess angiogenesis in the tumor microenvironment is microvascular density by using immunohistochemistry with antibodies against endothelial CD31, CD34 and CD105 antigens. Even smaller molecules, such as the microRNAs, which are small non-coding RNAs, are being studied for their usefulness as surrogate biomarkers of angiogenesis and prognosis. In this review, we will discuss recent advances regarding the investigation of angiogenesis, the crosstalk between elements of the immune microenvironment and angiogenesis and how a disorganized tumor vessel network affects the trafficking of CD8+ T cells in the tumor bed. Furthermore, we will present recent data from clinical trials that combine antiangiogenic therapies with immune checkpoint inhibitors in colorectal cancer.

The role of PDGFRA as a therapeutic target in young colorectal cancer patients

Background

Young patients with colorectal cancer (CRC) exhibit poor prognoses compared to older patients due to the difficulty in early diagnosis and treatment. However, the underlying molecular characteristics are still unclear.

Methods

We conducted a comprehensive analysis of 49 CRC patients without hereditary CRC using the whole-exome and RNA sequencing with tumor and matched normal samples. A total of 594 TCGA samples and 4 patient-derived cells were utilized for validation.

Results

Consensus molecular subtype 4 (CMS4) (53.85%) and CMS2 (38.46%) were enriched in the young (≤ 40 years) and old (> 60 years) age groups, respectively. A CMS4-associated gene, platelet-derived growth factor receptor α (PDGFRA), was significantly upregulated in young patients with CRC (FC = 3.21, p = 0.0001) and was negatively correlated with age (p = 0.0001, R = − 0.526). Moreover, PDGFRA showed a positive co-expression with metastasis-related genes in young CRC patients. In vitro validation confirmed that young patient-derived cells (PDCs) showed an enriched expression of PDGFRA compared to old PDCs and a reduced proliferation rate by knockdown of PDGFRA. Furthermore, young CRC patients were more sensitive to regorafenib, a PDGFRA-targeting drug, than old CRC patients.

Conclusions

Our study suggests that CRC in young patients is associated with CMS4 and PDGFRA. In addition, PDGFRA may serve potential of novel therapeutic strategies and represent a predictive biomarker of response to regorafenib for young CRC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03088-7.

A Claudin-Based Molecular Signature Identifies High-Risk, Chemoresistant Colorectal Cancer Patients

Identifying molecular characteristics that are associated with aggressive cancer phenotypes through gene expression profiling can help predict treatment responses and clinical outcomes. Claudins are deregulated in colorectal cancer (CRC). In CRC, increased claudin-1 expression results in epithelial-to-mesenchymal transition and metastasis, while claudin-7 functions as a tumor suppressor. In this study, we have developed a molecular signature based on claudin-1 and claudin-7 associated with poor patient survival and chemoresistance. This signature was validated using an integrated approach including publicly available datasets and CRC samples from patients who either responded or did not respond to standard-of-care treatment, CRC cell lines, and patient-derived rectal and colon tumoroids. Transcriptomic analysis from a patient dataset initially yielded 23 genes that were differentially expressed along with higher claudin-1 and decreased claudin-7. From this analysis, we selected a claudins-associated molecular signature including PIK3CA, SLC6A6, TMEM43, and ASAP-1 based on their importance in CRC. The upregulation of these genes and their protein products was validated using multiple CRC patient datasets, in vitro chemoresistant cell lines, and patient-derived tumoroid models. Additionally, blocking these genes improved 5-FU sensitivity in chemoresistant CRC cells. Our findings propose a new claudin-based molecular signature that associates with poor prognosis as well as characteristics of treatment-resistant CRC including chemoresistance, metastasis, and relapse.

Aflibercept Plus FOLFIRI as Second-Line Treatment for Metastatic Colorectal Cancer: A Single-Institution Real-Life Experience

Simple Summary

The continuum of care for mCRC might include anti-angiogenic drug as anti-VEGF/VEGFR moAb and recombinant proteins in combination with fluoropyrimidine-based regimens in first- and second-line treatment, and multikinase inhibitors in refractory patients. The addition of aflibercept to FOLFIRI has been demonstrated to improve survival in patients with metastatic colorectal cancer (mCRC) who progressed after receiving a standard oxaliplatin-based regimen. In this retrospective, single-institution, observational study we collected clinical data from mCRC patients who received aflibercept in combination with FOLFIRI in routine clinical practice to describe feasibility and efficacy of this regimen in a real-world population. Aflibercept-FOLFIRI is a feasible second-line treatment for mCRC in a real-life setting, and PFS in first-line therapy >12 months resulted as the only predictive marker of better survival.

Abstract

The addition of aflibercept to FOLFIRI has been demonstrated to improve survival in patients with metastatic colorectal cancer (mCRC) who progressed after receiving a standard oxaliplatin-based regimen. In this retrospective, single-institution, observational study we collected clinical data from mCRC patients who received aflibercept in combination with FOLFIRI in routine clinical practice from October 2012 to March 2021 to describe feasibility and efficacy of this regimen in a real-world population. Forty-nine patients receiving aflibercept-FOLFIRI as second-line treatment were identified, 40.8% of whom were aged over 65 years. The majority of patients had multi-organ metastases (73.5%), and had previously received bevacizumab in combination with chemotherapy (CT) as first-line treatment (79.6%). Median overall survival (OS) and progression-free survival (PFS) were 13 and 6 months, respectively; overall response rate (ORR) and disease control rate (DCR) were 12.3% and 49.1%, respectively. Several factors were associated with survival in univariate analysis, including PFS in first-line therapy, number of metastatic sites, bone metastases and others. However, in multivariate analysis, only PFS in first-line CT over 12 months was significantly associated with better OS (HR 0.32; 95% CI 0.13–0.79; p = 0.01). Hypertension was the most commonly reported grade (G) 3–4 adverse event (AE), affecting 18.4% of the overall population. Thromboembolic events were observed in 16.3% of patients, hemorrhagic events in 10.2%, and proteinuria in 8.2%. Neutropenia was the most frequently observed hematological G3–4 AE with an incidence of 10.2%. Aflibercept-FOLFIRI has been confirmed as a feasible second-line treatment for mCRC in a re-al-life setting, and PFS in first-line therapy >12 months resulted as the only predictive marker of better survival.

Are All Anti-Angiogenic Drugs the Same in the Treatment of Second-Line Metastatic Colorectal Cancer? Expert Opinion on Clinical Practice

Targeting tumor-driven angiogenesis is an effective strategy in the management of metastatic colorectal cancer (mCRC); however, the choice of second-line therapy is complicated by the availability of several drugs, the occurrence of resistance and the lack of validated prognostic and predictive biomarkers. This review examines the use of angiogenesis-targeted therapies for the second-line management of mCRC patients. Mechanisms of resistance and anti-placental growth factor agents are discussed, and the role of aflibercept, a recombinant fusion protein consisting of portions of human vascular endothelial growth factor receptor (VEGFR)-1 and VEGFR-2, is highlighted. The novel mechanism of action of aflibercept makes it a useful second-line agent in mCRC patients progressing after oxaliplatin-based chemotherapy, as well as in those with resistance after bevacizumab.

Tumor Microenvironment in Metastatic Colorectal Cancer: The Arbitrator in Patients' Outcome

Simple Summary

Colorectal cancer accounts for approximately 10% of all annually diagnosed cancers worldwide being liver metastasis, the most common cause of death in patients with colorectal cancer. The interplay between tumor and stromal cells in the primary tumor microenvironment and at distant metastases are rising in importance as potential mechanisms of the tumor progression. In this review we discuss the new biomarkers derived from tumor microenvironment and liquid biopsy as emerging prognostic and treatments response markers for metastatic colorectal cancer. We also review the developing new clinical strategies based on tumor microenvironmental cells to tackle metastatic disease in metastatic colorectal cancer patients.

Abstract

Colorectal cancer (CRC) is one of the most common cancers in western countries. Its mortality rate varies greatly, depending on the stage of the disease. The main cause of CRC mortality is metastasis, which most commonly affects the liver. The role of tumor microenvironment in tumor initiation, progression and metastasis development has been widely studied. In this review we summarize the role of the tumor microenvironment in the liver pre-metastatic niche formation, paying attention to the distant cellular crosstalk mediated by exosomes. Moreover, and based on the prognostic and predictive capacity of alterations in the stromal compartment of tumors, we describe the role of tumor microenvironment cells and related liquid biopsy biomarkers in the delivery of precise medication for metastatic CRC. Finally, we evaluate the different clinical strategies to prevent and treat liver metastatic disease, based on the targeting of the tumor microenvironment. Specifically, targeting angiogenesis pathways and regulating immune response are two important research pipelines that are being widely developed and promise great benefits.

Chemosensitization of HT29 and HT29-5FU Cell Lines by a Combination of a Multi-Tyrosine Kinase Inhibitor and 5FU Downregulates ABCC1 and Inhibits PIK3CA in Light of Their Importance in Saudi Colorectal Cancer

Colorectal cancer (CRC) remains one of the main causes of death worldwide and in Saudi Arabia. The toxicity and the development of resistance against 5 fluorouracil 5FU pose increasing therapeutic difficulties, which necessitates the development of personalized drugs and drug combinations. Objectives: First, to determine the most important kinases and kinase pathways, and the amount of ABC transporters and KRAS in samples taken from Saudi CRC patients. Second, to investigate the chemosensitizing effect of LY294002 and HAA₂₀₂₀ and their combinations with 5FU on HT29, HT29-5FU, HCT116, and HCT116-5FU CRC cells, their effect on the three ABC transporters, cell cycle, and apoptosis, in light of the important kinase pathways resulting from the first part of this study. Methods: The PamChip^® peptide micro-array profiling was used to determine the level of kinase and targets in the Saudi CRC samples. Next, RT-PCR, MTT cytotoxicity, Western blotting, perturbation of cell cycle, annexin V, and immunofluorescence assays were used to investigate the effect on CRC, MRC5, and HUVEC cells. Results: The kinase activity profiling highlighted the importance of the PI3K/AKT, MAPK, and the growth factors pathways in the Saudi CRC samples. PIK3CA was the most overexpressed, and it was associated with increased level of mutated KRAS and the three ABC transporters, especially ABCC1 in the Saudi samples. Next, combining HAA₂₀₂₀ with 5FU exhibited the best synergistic and resistance-reversal effect in the four CRC cells, and the highest selectivity indices compared to MRC5 and HUVEC normal cells. Additionally, HAA₂₀₂₀ with 5FU exerted significant inhibition of ABCC1 in the four CRC cells, and inhibition of PIK3CA/AKT/MAPK7/ERK in HT29 and HT29-5FU cells. The combination also inhibited EGFR, increased the preG₁/S cell cycle phases, apoptosis, and caspase 8 in HT29 cells, while it increased the G₁ phase, p21/p27, and apoptosis in HT29-5FU cells. Conclusion: We have combined the PamChip kinase profiling of Saudi CRC samples with in vitro drug combination studies in four CRC cells, highlighting the importance of targeting PIK3CA and ABCC1 for Saudi CRC patients, especially given that the overexpression of PIK3CA mutations was previously linked with the lack of activity for the anti-EGFRs as first line treatment for CRC patients. The combination of HAA₂₀₂₀ and 5FU has selectively sensitized the four CRC cells to 5FU and could be further studied.

Gemcitabine and Rapamycin Exhibit Additive Effect against Osteosarcoma by Targeting Autophagy and Apoptosis

The overall prognosis for sarcoma-based cancer patients has remained largely unchanged over the past 10 years. Because there is no effective anticancer drug for patients with chemoresistant osteosarcoma (OS), novel approaches are needed to improve the prognosis. Here, we investigated whether rapamycin (Rapa) could enhance the anti-tumor effects of gemcitabine (Gem) in OS. Gem dose-dependently killed the OS cells, but exhibited much lower cytotoxicity on osteoblasts. Treatment with a combination Gem and Rapa was much more effective than that of either single agent with respect to reducing cell viability, cell invasion, cell migration, and vascular endothelial growth factor production in vitro. Moreover, the combination of these agents suppressed tumor growth, angiogenesis, and lung metastasis in allograft and xenograft murine models of OS with minimal adverse effects. Overall, the combination therapy prolonged the overall survival of tumor-bearing mice. Mechanistically, Gem induced apoptosis and increased the levels of cleaved caspases, while Rapa induced autophagy and microtubule-associated protein light chain 3 (LC3)-I/LC3-II expression both in vitro and in vivo. Our findings suggest that chemotherapy using Gem combined with Rapa may be a novel and promising therapeutic approach for the treatment of OS.

Cyclodextrin inclusion complex inhibits circulating galectin-3 and FGF-7 and affects the reproductive integrity and mobility of Caco-2 cells

Galectin-3 (Gal-3) is a carbohydrate-binding protein, that promotes angiogenesis through mediating angiogenic growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). There is strong evidence confirming FGF involvement in tumor growth and progression by disrupting cell proliferation and angiogenesis. In this study, we investigated the effect of β-cyclodextrin:everolimus:FGF-7 inclusion complex (Complex) on Caco-2 cell migration, cell motility and colony formation. In addition, we examined the inhibitory effect of the Complex on the circulating proteins; Gal-3 and FGF-7. Swiss Target Prediction concluded that Gal-3 and FGF are possible targets for β-CD. Results of the chemotaxis cell migration assay on Caco-2 cell line revealed that the Complex has higher reduction in cell migration (78.3%) compared to everolimus (EV) alone (58.4%) which is possibly due to the synergistic effect of these molecules when used as a combined treatment. Moreover, the Complex significantly decreased the cell motility in cell scratch assay, less than 10% recovery compared to the control which has ~ 45% recovery. The Complex inhibited colony formation by ~ 75% compared to the control. Moreover, the Complex has the ability to inhibit Gal-3 with minimum inhibitory concentration of 33.46 and 41 for β-CD and EV, respectively. Additionally, β-CD and β-CD:EV were able to bind to FGF-7 and decreased the level of FGF-7 more than 80% in cell supernatant. This confirms Swiss Target Prediction result that predicted β-CD could target FGF. These findings advance the understanding of the biological effects of the Complex which reduced cell migration, cell motility and colony formation and it is possibly due to inhibiting circulating proteins such as; Gal-3 and FGF-7.

Decrypting the Molecular Mechanistic Pathways Delineating the Chemotherapeutic Potential of Ruthenium-Phloretin Complex in Colon Carcinoma Correlated with the Oxidative Status and Increased Apoptotic Events

To explore fresh strategies in colorectal cancer (CRC) chemotherapy, we evaluated the capability of the ruthenium-phloretin complex in exterminating colon cancer by effectively addressing multiple apoptotic mechanisms on HT-29 cancer cells together with an animal model of colorectal cancer activated by 1,2-dimethylhydrazine and dextran sulfate sodium. Our current approach offers tangible evidence of the application of the ruthenium-phloretin complex in future chemotherapy. The complex triggers intrinsic apoptosis triggered by p53 and modulates the Akt/mTOR pathway along with other inflammatory biomarkers. The ruthenium-phloretin complex has been synthesized and successfully characterized by numerous spectroscopic methodologies accompanied by DPPH, FRAP, and ABTS assays assessing its antioxidant potential. Studies conducted in human cell lines revealed that the complex improved levels of p53 and caspase-3 while diminishing the activities of VEGF and mTOR, triggers apoptosis, and induces fragmentation of DNA in the HT-29 cells. Toxicity studies were conducted to identify the therapeutic doses of the novel complex in animal models. The outcomes of the in vivo report suggest that the complex was beneficial in repressing multiplicity of aberrant crypt foci as well as hyperplastic lesions and also promoted increased levels of CAT, SOD, and glutathione. In addition, the ruthenium-phloretin complex was able to control cell proliferation and boosted apoptotic outbursts in cancer cells associated with the increase in cellular response towards Bax while diminishing responses towards Bcl-2, NF-κB, and MMP-9. Our observations from the experiments deliver testament that the ruthenium-phloretin complex has the potential to act as a promising chemotherapeutic agent in colorectal cancer because it can affect the growth of ACF and hyperplastic abrasions in the colon tissues by evoking cell death.

Pharmacogenetics in Model-Based Optimization of Bevacizumab Therapy for Metastatic Colorectal Cancer

Vascular endothelial growth factor A (VEGF-A) and intercellular adhesion molecule 1 (ICAM-1) are significant regulators of angiogenesis, an important biological process involved in carcinogenesis. Bevacizumab, an anti-VEGF monoclonal antibody (MAB), is approved for the treatment of metastatic Colorectal cancer (mCRC), however clinical outcomes are highly variable. In the present study, we developed a pharmacokinetic (PK), a simplified quasi-steady state (QSS) and a pharmacokinetic/pharmacodynamic (PK/PD) model to identify potential sources of variability. A total of 46 mCRC patients, who received bevacizumab in combination with chemotherapy were studied. VEGF-A (rs2010963, rs1570360, rs699947) and ICAM-1 (rs5498, rs1799969) genes’ polymorphisms, age, gender, weight, and dosing scheme were investigated as possible co-variates of the model’s parameters. Polymorphisms, trough, and peak levels of bevacizumab, and free VEGF-A were determined in whole blood and serum. Data were analyzed using nonlinear mixed-effects modeling. The two-compartment PK model showed that clearance (CL) was significantly lower in patients with mutant ICAM-1 rs1799969 (p < 0.0001), inter-compartmental clearance (Q) was significantly higher with mutant VEGF-A rs1570360 (p < 0.0001), and lower in patients with mutant VEGF-A rs699947 (p < 0.0001). The binding QSS model also showed that mutant ICAM-1 rs1799969 was associated with a lower CL (p = 0.0177). Mutant VEGF-A rs699947 was associated with a lower free VEGF-A levels, prior to the next dose (p = 0.000445). The above results were confirmed by the PK/PD model. Findings of the present study indicated that variants of the genes regulating angiogenesis might affect PK and PD characteristics of bevacizumab, possibly influencing the clinical outcomes.

The circular RNA 001971/miR-29c-3p axis modulates colorectal cancer growth, metastasis, and angiogenesis through VEGFA

Background

Colorectal cancer (CRC) is one of the most common malignant tumors globally. Angiogenesis is a key event maintaining tumor cell survival and aggressiveness. The expression of vascular endothelial growth factor A (VEGFA), one of the most significant tumor cell-secreted proangiogenic factors, is frequently upregulated in CRC.

Methods

The MTT assay was used to detect the viability of CRC cells. Transwell assays were performed to detect the invasion capacity of target cells. Relative protein levels were determined by immunoblotting. Pathological characteristics of tissues were detected by H&E staining and immunohistochemical (IHC) staining. A RIP assay was conducted to validate the predicted binding between genes.

Results

We observed that circ-001971 expression was dramatically increased in CRC tissue samples and cells. Circ-001971 knockdown suppressed the capacity of CRC cells to proliferate and invade and HUVEC tube formation in vitro, as well as tumor growth in mice bearing SW620 cell-derived tumors in vivo. The expression of circ-001971 and VEGFA was dramatically increased whereas the expression of miR-29c-3p was reduced in tumor tissue samples. Circ-001971 relieved miR-29c-3p-induced inhibition of VEGFA by acting as a ceRNA, thereby aggravating the proliferation, invasion and angiogenesis of CRC. Consistent with the above findings, the expression of VEGFA was increased, whereas the expression of miR-29c-3p was decreased in tumor tissue samples. miR-29c-3p had a negative correlation with both circ-001971 and VEGFA, while circ-001971 was positively correlated with VEGFA.

Conclusions

In conclusion, the circ-001971/miR-29c-3p axis modulated CRC cell proliferation, invasion, and angiogenesis by targeting VEGFA.

Molecular-Biology-Driven Treatment for Metastatic Colorectal Cancer

BACKGROUND

Metastatic CRC (mCRC) is a molecular heterogeneous disease. The aim of this review is to give an overview of molecular-driven treatment of mCRC patients.

METHODS

A review of clinical trials, retrospective studies and case reports was performed regarding molecular biomarkers with therapeutic implications.

RESULTS

RAS wild-type status was confirmed as being crucial for anti-epidermal growth factor receptor (EGFR) monoclonal antibodies and for rechallenge strategy. Antiangiogenic therapies improve survival in first- and second-line settings, irrespective of RAS status, while tyrosine kinase inhibitors (TKIs) remain promising in refractory mCRC. Promising results emerged from anti-HER2 drugs trials in HER2-positive mCRC. Target inhibitors were successful for BRAFV600E mutant mCRC patients, while immunotherapy was successful for microsatellite instability-high/defective mismatch repair (MSI-H/dMMR) or DNA polymerase epsilon catalytic subunit (POLE-1) mutant patients. Data are still lacking on NTRK, RET, MGMT, and TGF-β, which require further research.

CONCLUSION

Several molecular biomarkers have been identified for the tailored treatment of mCRC patients and multiple efforts are currently ongoing to increase the therapeutic options. In the era of precision medicine, molecular-biology-driven treatment is the key to impro patient selection and patient outcomes. Further research and large phase III trials are required to ameliorate the therapeutic management of these patients.

Medicinal Plants Extracts with Antiangiogenic Activity: Where Is the Link?

Angiogenesis is a strictly controlled process defined as the formation of new blood vessels essential for certain physiologic and pathologic conditions where the latter includes tumor growth, development, and metastasis. Thus, inhibiting angiogenesis along with other anticancer strategies such as chemotherapy seems to be invaluable for reaching an optimal outcome in cancer patients. It has been shown that some natural plant-derived compounds are capable of preventing the formation of these new blood vessels in the tumor and also inhibit the proliferation and growth of the cancer cells. In this review, we intend to introduce plants with anti-angiogenic properties and discuss their related features.

Expression of pro-angiogenic factors as potential biomarkers in experimental models of colon cancer

PURPOSE

RAS mutational status in colorectal cancer (CRC) represents a predictive biomarker of response to anti-EGFR therapy, but to date it cannot be considered an appropriate biomarker of response to anti-VEGF therapy. To elucidate the function of K-Ras in promoting angiogenesis, the effect of conditioned media from KRAS mutated and wild type colon cancer cell lines on HUVECs tubule formation ability and the correspondent production of pro-angiogenic factors have been evaluated by a specific ELISA assay.

METHODS

Ras-activated signaling pathways were compared by western blot analysis and RTq-PCR. In addition, VEGF, IL-8, bFGF and HIF-1α expression was determined in K-RAS silenced cells. Furthermore, we conducted an observational study in a cohort of RAS mutated metastatic CRC patients, treated with first-line bevacizumab-based regimens, evaluating VEGF-A and IL-8 plasma levels at baseline, and during treatment.

RESULTS

K-RAS promotes VEGF production by cancer cell lines. At the transcriptional level, this is reflected to a K-RAS dependent HIF-1α over-expression. Moreover, the HIF-1α, VEGF and FGF expression inhibition in KRAS knocked cells confirmed these results. Within the clinical part, no statistically significant correlation has been found between progression-free survival (PFS) and VEGF-A/IL-8 levels, but we cannot exclude that these biomarkers could be further investigated as predictive or prognostic biomarkers in this setting.

CONCLUSION

Our study confirmed the direct involvement of K-Ras in promoting angiogenesis into colon cancer cell lines.

Carcinoma and Sarcoma Microenvironment at a Glance: Where We Are

Cells and extracellular matrix (ECM) components represent the multifaceted and dynamic environment that distinguishes each organ. Cancer is characterized by the dysregulation of the composition and structure of the tissues, giving rise to the tumor milieu. In this review, we focus on the microenvironmental analysis of colorectal cancer (CRC) and rhabdomyosarcoma (RMS), two different solid tumors. While a lot is known about CRC environment, for RMS, this aspect is mostly unexplored. Following the example of the more complete CRC microenvironmental characterization, we collected and organized data on RMS for a better awareness of how tissue remodeling affects disease progression.

hERG1 and HIF-2α Behave as Biomarkers of Positive Response to Bevacizumab in Metastatic Colorectal Cancer Patients

Background: In search of novel biomarkers of response to bevacizumab in metastatic colorectal cancer (mCRC), we analyzed the expression and prognostic role of several proteins related to angiogenesis. Methods: A retrospective, multicenter study on 80 surgical samples from mCRC patients treated in first line with bevacizumab plus chemotherapy was accomplished. The following proteins were analyzed by immunohistochemistry: hERG1 potassium channel, β1-integrin, pAKT, NFkB, HIF-1α, HIF-2α, p53, VEGF-A, GLUT-1, and CA-IX. Data were analyzed in conjunction with the clinicopathological characteristics of the patients, KRAS status, response to bevacizumab, and follow-up. Results: (1) All the proteins were expressed in the samples, with statistically significant associations between HIF-1α and gender, HIF-2α and left colon, hERG1 and VEGF-A, β1-integrin and HIF-2α, GLUT-1 and both HIF-1α and HIF-2α, and CA-IX and VEGF-A. (2) At the univariate analysis, positivity for hERG1, VEGF-A, and the active form of HIF-2α (aHIF-2α), and the G3 histological grade showed a positive impact on progression-free survival (PFS). (3) hERG1 and aHIF-2α maintained their positive impact on PFS at the multivariate analysis. (4) hERG1 behaved as a protective factor for PFS independently on KRAS status. Conclusions: hERG1 and aHIF-2α might help to identify patients who would benefit from bevacizumab treatment.

The Role of p53-Mediated Signaling in the Therapeutic Response of Colorectal Cancer to 9F, a Spermine-Modified Naphthalene Diimide Derivative

Colorectal cancer (CRC) is one of the most prevalent cancers due to its frequency and high rate of mortality. Polyamine-vectorized anticancer drugs possess multiple biological properties. Of these drugs, 9F has been shown to inhibit tumor growth and the metastasis of hepatocellular carcinoma. This current study aims to investigate the effects of 9F on CRC and determine its molecular mechanisms of action. Our findings demonstrate that 9F inhibits CRC cell growth by inducing apoptosis and cell cycle arrest, and suppresses migration, invasion and angiogenesis in vitro, resulting in the inhibition of tumor growth and metastasis in vivo. Based on RNA-seq data, further bioinformatic analyses suggest that 9F exerts its anticancer activities through p53 signaling, which is responsible for the altered expression of key regulators of the cell cycle, apoptosis, the epithelial-to-mesenchymal transition (EMT), and angiogenesis. In addition, 9F is more effective than amonafide against CRC. These results show that 9F can be considered as a potential strategy for CRC treatment.

Molecular Modeling-Based Delivery System Enhances Everolimus-Induced Apoptosis in Caco-2 Cells

Several studies have shown that the mammalian target of rapamycin (mTOR) inhibitor; everolimus (EV) improves patient survival in several types of cancer. However, the meaningful efficacy of EV as a single agent for the treatment of colorectal cancer (CRC) has failed to be proven in multiple clinical trials. Combination therapy is one of the options that could increase the efficacy and decrease the toxicity of the anticancer therapy. This study revealed that the β-cyclodextrin (β-CD):FGF7 complex has the potential to improve the antiproliferative effect of EV by preventing FGF receptor activation and by enhancing EV cellular uptake and intracellular retention. Molecular docking techniques were used to investigate the possible interaction between EV, β-CD, and FGF7. Molecular docking insights revealed that β-CD and EV are capable to form a stable inclusion complex with FGF at the molecular level. The aqueous solubility of the inclusion complex was increased (3.1 ± 0.23 μM) when compared to the aqueous solubility of pure EV (1.7 ± 0.16 μM). In addition, the in vitro cytotoxic activity of a FGF7:β-CD:EV complex on Caco-2 cell line was investigated using real-time xCELLigence technology. The FGF7:β-CD:EV complex has induced apoptosis of Caco-2 cells and shown higher cytotoxic activity than the parent drug EV. With the multitargets effect of β-CD:FGF7 and EV, the antiproliferative effect of EV was remarkably improved as the IC₅₀ value of EV was reduced from 9.65 ± 1.42 to 1.87 ± 0.33 μM when compared to FGF7:β-CD:EV complex activity. In conclusion, the findings advance the understanding of the biological combinational effects of the β-CD:FGF7 complex and EV as an effective treatment to combat CRC.

miR-148a inhibits early relapsed colorectal cancers and the secretion of VEGF by indirectly targeting HIF-1α under non-hypoxia/hypoxia conditions

Vascular endothelial growth factor (VEGF) is correlated with angiogenesis and early relapse of colorectal cancer (CRC). This study investigated the role of miR-148a in the regulation of VEGF/angiogenesis and early relapse of CRC. We established a stable clone with miR-148a expression in HCT116 and HT29 cell lines and created a hypoxic condition by using CoCl2 to determine the underlying mechanism of miR-148a. The effects of miR-148a on the phosphoryl-ERK (pERK)/hypoxia-inducible factor-1α (HIF-1α)/VEGF pathway were evaluated through Western blotting and the inhibitory effect of miR-148a on angiogenesis was demonstrated through a tube formation assay. Sixty-three CRC tissues (28 early relapse and 35 non-early relapse) were analysed to assess the relationship between miR-148a and HIF-1α/VEGF. The protein expression of pERK/HIF-1α/VEGF in HCT116 and HT29 cells was significantly decreased by miR-148a (all P < 0.05). The protein expression of VEGF/HIF-1α was strongly inversely associated with the expression of miR-148a in the 63 CRC tissue samples (all P < 0.05). Tube formation assay demonstrated that miR-148a significantly obliterated angiogenesis. miR-148a suppresses VEGF through down-regulation of the pERK/HIF-1α/VEGF pathway and might lead to the inhibition of angiogenesis; miR-148a down-regulation increased the early relapse rate of CRC. This demonstrates that miR-148a is a potential diagnostic and therapeutic target.

Inflammation- and angiogenesis-related biomarkers are correlated with cancer-related fatigue in colorectal cancer patients: Results from the ColoCare Study

Cancer-related fatigue is one of the most common side effects of colorectal cancer treatment and is affected by biomedical factors. We investigated the association of inflammation- and angiogenesis-related biomarkers with cancer-related fatigue. Pre-surgery (baseline) serum samples were obtained from n = 236 newly diagnosed colorectal cancer patients. Meso Scale Discovery assays were performed to measure levels of biomarkers for inflammation and angiogenesis (CRP, SAA, IL-6, IL-8, MCP-1, sICAM-1, sVCAM-1, TNFα, VEGFA and VEGFD). Cancer-related fatigue was assessed with the EORTC QLQ-30 questionnaire at baseline and 6 and 12 months post-surgery. We tested associations using Spearman's partial correlations and logistic regression analyses, adjusting for age, sex and body mass index. sICAM-1 and VEGFD showed a significant positive correlation with cancer-related fatigue at baseline and 6-, and 12-month follow-up (sICAM-1: r = 0.19, p = 0.010; r = 0.24, p = 0.004; r = 0.25, p = 0.006; VEGFD: r = 0.20, p = 0.006; r = 0.15, p = 0.06; r = 0.23, p = 0.01 respectively). Biomarkers of inflammation and angiogenesis measured prior to surgery are associated with cancer-related fatigue in colorectal cancer patients throughout various time points. Our results suggest the involvement of overexpressed sICAM-1 and VEGFD in the development of fatigue.

Construing the Biochemical and Molecular Mechanism Underlying the In Vivo and In Vitro Chemotherapeutic Efficacy of Ruthenium-Baicalein Complex in Colon Cancer

In pursuit of a novel approach in colon cancer therapy, we explored the ability of ruthenium baicalein complex to eradicate colon cancer by efficiently targeting various apoptotic pathways on human colon cancer cell line and on a DMH and DSS induced murine model of colorectal cancer. In this study, we provide direct proof of the chemotherapeutic potential of the ruthenium baicalein complex by activating p-53 dependent intrinsic apoptosis and modulating the AKT/mTOR and WNT/β- catenin pathways. The ruthenium baicalein complex was synthesized and its characterizations were accomplished through various spectroscopic techniques followed by assessment of antioxidant potential by DPPH, FRAP, and ABTS methods. In vitro study established that the complex increased p53 and caspase-3 expressions while down regulating VEGF and mTOR expression, induced apoptosis, and DNA fragmentation in the HT-29 cells. Acute and sub-acute toxicity study was also considered and results from in vivo study revealed that complex was effective in suppressing ACF multiplicity and hyperplastic lesions and also raised the CAT, SOD, and glutathione levels. Furthermore, the complex decreased cell proliferation and increased apoptotic events in tumor cells correlated with the upregulation of Bax and downregulation of Bcl2, WNT and β- catenin expressions. Our findings from the in vitro and in vivo study provide robust confirmation that ruthenium baicalein complex possesses a potential chemotherapeutic activity against colon cancer and is competent in reducing ACF multiplicity, hyperplastic lesions in the colon tissues of rats by inducing apoptosis.

microRNA-769 is downregulated in colorectal cancer and inhibits cancer progression by directly targeting cyclin-dependent kinase 1

BACKGROUND

In recent years, microRNAs (miRNAs) have been reported to be aberrantly expressed in colorectal cancer (CRC). The deregulation of miRNAs is implicated in the formation and progression of CRC, and participates in the regulation of a wide range of biological behaviors. Considering the crucial role of miRNAs in CRC, miRNAs are thought to have significant promise in the diagnosis and therapy of patients with this malignancy.

MATERIAL AND METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-769 expression in CRC tissues and cell lines. MTT assay and flow cytometry analysis were used to determine the effects of miR-769 upregulation in CRC cell proliferation and apoptosis, respectively. The influence of miR-769 overexpression in CRC cell migration and invasion was evaluated through migration and invasion assays. Notably, the possible mechanisms underlying the action of miR-769 in CRC cells were explored.

RESULTS

In the present study, miR-769 was frequently found to be poorly expressed in CRC tissues and cell lines. Functional assays showed that recovery of miR-769 expression suppressed CRC cell proliferation, migration, and invasion, increased cell apoptosis in vitro, and inhibited tumor growth in vivo. Cyclin-dependent kinase 1 (CDK1) was the direct target of miR-769 in CRC cells. CDK1 was overexpressed in CRC tissue samples and negatively correlated with miR-769 expression. In addition, CDK1 inhibition imitated the tumor suppressor activity of miR-769 in CRC cells, and restoration of CDK1 expression partially abolished the tumor-suppressing roles of miR-769 in malignant CRC cells.

CONCLUSION

The results of this study demonstrated that miR-769 was downregulated in CRC and directly targeted CDK1 to be implicated in the regulation of CRC cell proliferation, apoptosis, migration and invasion. Thus, the miR-769/CDK1 axis might be an effective therapeutic target for treating patients with CRC.

Role of hypoxia-induced exosomes in tumor biology

Purpose

Hypoxia is a major regulator of angiogenesis and always influences the release of exosomes in various types of tumors. The present review aimed to assess the role of hypoxia-induced exosomes in the tumor biology.

Methods

The relevant publications were retrieved from PubMed using keywords such as hypoxia, exosome, extracellular vesicles, tumor, cancer, and other similar terms.

Results

Recent studies have shown that cancer cells produce more exosomes under hypoxic conditions than do parental cells under normoxic conditions. The secretion and function of exosomes could be influenced by hypoxia in various types of cancer. Hypoxia-induced exosomes play critical roles in tumor angiogenesis, invasion, metastasis, and the immune system.

Conclusions

These findings provide new insights into the complex networks underlying cellular and genomic regulation in response to hypoxia and might provide novel and specific targets for future therapies.

Validation of Bevacizumab Therapy Effect on Colon Cancer Subtypes by Using Whole Body Imaging in Mice

PURPOSE

Preclinical imaging offers a useful tool for monitoring cancer biological behavior and therapy in vivo without the necessity of animal surgery. The following paper describes our examination of tumor progress and anti-angiogenic therapy with Bevacizumab on colon cancer subtypes (SW480 and SW620) by using different non-invasive real-time in vivo imaging techniques.

PROCEDURES

Color Doppler ultrasound imaging (CDUI) was used to observe the formation of new blood vessels; a homemade fluorescence reflectance imaging (FRI) apparatus was mainly used to test the difference in VEGFR2 expression between the tumor subtypes. Briefly, 15 Balb/c nude mice bearing subcutaneous SW480 and SW620 xenografts were randomly divided into Control and Drug groups. Bevacizumab treatment lasted for 3 weeks. All images were captured pre- and post-treatment. At the end of experiment, all mice were euthanized, and tumor tissue was collected and analyzed by immunohistochemical staining.

RESULTS

Expression of VEGFR2 was found to be slightly (10 %) but significantly higher for the SW620 cells than for SW480 cells. In addition, SW620 has shown to be more vascularized than SW480 subtype. After 3-week Bevacizumab therapy, no blood vessels were found within 83 % of SW620, while it was 67 % in SW480; the increase of SW620 tumor volume post-treatment was only 3.17-fold compared with the tumor volume pre-treatment, and 4.51-fold higher in SW480.

CONCLUSION

Our data suggest that SW480 and SW620 cell lines respond differently to Bevacizumab therapy in vivo. Because of higher vascularization, and subsequently higher reduction by drug of new blood vessels and tumor growth rate, xenografts derived from the metastatic SW620 cell line have a better chance of being successfully treated with Bevacizumab compared with those derived from the primary tumor SW480 cell line.

Silencing NIK potentiates anti-VEGF therapy in a novel 3D model of colorectal cancer angiogenesis

Angiogenesis is essential for colorectal cancer (CRC) progression, as demonstrated by the beneficial clinical effects of therapeutics inhibiting VEGF signaling. However, alternative mechanisms of neovascularization can develop, resulting in treatment failure. Previously we demonstrated NF-κB-inducing kinase (NIK) contributes to pathological angiogenesis. Here, we investigate NIK as a therapeutic target in endothelial cells (EC) in CRC. To determine NIK expression levels in CRC tissues, we immunostained both primary colorectal tumors and tumors metastasized to the liver. Additionally, a 3D tumor-stromal cell interaction model was developed including EC, fibroblasts and CRC cells to study tumor angiogenesis. This model tested efficacy of NIK-targeting siRNA (siNIK) in EC alone or in combination with the anti-VEGF antibody, bevacizumab. Both primary CRC and liver metastases contained blood vessels expressing NIK. In patients receiving chemotherapy plus bevacizumab, immature NIK⁺ vessels (p < 0.05) were increased as compared to chemotherapy alone. Activation of NIK by lymphotoxin-beta receptor (LTβR) induced increases in pro-angiogenic mediators, including interleukin (IL)-6, IL-8, chemokine (C-X-C motif) ligand (CXCL)1 and CXCL5 in EC and fibroblasts, accompanied by sprouting in the 3D model, which was blocked by siNIK in EC. Treatment with bevacizumab plus siNIK in EC resulted in a synergistic effect and reduced VEGF and bFGF-induced sprouting (p < 0.05). Here, we demonstrate a role for NIK in CRC-associated angiogenesis. Targeting NIK in EC in combination with anti-VEGF antibody bevacizumab may hold therapeutic potential to increase efficiency in blocking tumor neovascularization, either to prevent treatment failure due to activation of accessory pathways such as NF-κB signaling or as a rescue treatment.

Correlations between CD34 Immunolabelled Blood Vessels and CD34 mRNA Expression in Colorectal Cancer

Purpose: This study aims to determine the correlation between microvessel density of CD34 immunolabelled blood vessels and CD34 mRNA gene expression in colorectal cancer tissue. Material/Methods: Standard immunohistochemistry and gene expression was perform on samples collected from 76 patients with colorectal cancer in order to determinate the number of CD34 immunolabelled blood vessels and the relative quantity of CD34 mRNA. Results: For the study group, the mean CD34 immunolabelled microvascular density (MVD) was of 307/mm², and the mean CD34 gene expression value for colon cancer was 2.303. The low p value (<0.001) of the Spearman correlation test showed a significant direct correlation between CD34 MVD and CD34 gene expression for the entire study group. Conclusions: CD34 gene`s expression can be looked at as a prognostic factor in colorectal cancer.

The role of tumor angiogenesis as a therapeutic target in colorectal cancer

INTRODUCTION

Angiogenesis is a complex process regulated by several pro- and anti-angiogenic factors, thus the loss of its fine equilibrium plays a key role in colorectal cancer (CRC) development and progression. Therapeutic agents targeting VEGF/VEGFR signaling, the main regulator of this process, proved to be effective across different treatment lines in metastatic CRC (mCRC) and contributed greatly to improve patients' survival in recent years. Areas covered: This review aimed to summarize the actual body of knowledge available on the VEGF pathway in CRC, including currently available anti-angiogenic drugs and treatment challenges, mechanisms of resistance, promising predictive biomarkers and future perspectives. Expert commentary: Angiogenesis inhibition in subsequent lines of treatment is a valid strategy in the continuum of care of mCRC patients. In this scenario, the availability of multiple agents warrants to tailor therapy to an individualized approach. However, the validation of predictive biomarkers to aid therapeutic decisions remains an issue. Intrinsic and adaptive resistance to anti-angiogenic agents comprises distinct and intertwined processes, eventually leading to treatment failure and disease progression. The expanding knowledge on the mechanisms underlying the angiogenesis pathway, different potential treatment targets and mechanisms of tumor resistance, may lead to promising new perspectives in this field.

Classical VEGF, Notch and Ang signalling in cancer angiogenesis, alternative approaches and future directions (Review)

Angiogenesis is the formation of new vessels starting from pre-existing vasculature. Tumour environment is characterized by 'aberrant angiogenesis', whose main features are tortuous and permeable blood vessels, heterogeneous both in their structure and in efficiency of perfusion and very different from normal vessels. Therapeutic strategies targeting the three pathways chiefly involved in tumour angiogenesis, VEGF, Notch and Ang signalling, have been identified to block the vascular supply to the tumour. However, phenomena of toxicity, development of primary and secondary resistance and hypoxia significantly blunted the effects of anti-angiogenic drugs in several tumour types. Thus, different strategies aimed to overcome these problems are imperative. The focus of the present review was some principal 'alternative' approaches to classic antiangiogenic therapies, including the cyclooxygenase-2 (COX-2) blockade, the use of oligonucleotide complementary to the miRNA to compete with the mRNA target (antimiRs) and the inhibition of matrix metalloproteinases (MMPs). The role of blood soluble VEGFA as a predictive biomarker during antiangiogenic therapy in gastric, ovarian and colorectal cancer was also examined.

EGFR-mediated macrophage activation promotes colitis-associated tumorigenesis

Epidermal growth factor receptor (EGFR) signaling is a known mediator of colorectal carcinogenesis. Studies have focused on the role of EGFR signaling in epithelial cells, although the exact nature of the role of EGFR in colorectal carcinogenesis remains a topic of debate. Here, we present evidence that EGFR signaling in myeloid cells, specifically macrophages, is critical for colon tumorigenesis in the azoxymethane-dextran sodium sulfate (AOM-DSS) model of colitis-associated carcinogenesis (CAC). In a human tissue microarray, colonic macrophages demonstrated robust EGFR activation in the pre-cancerous stages of colitis and dysplasia. Utilizing the AOM-DSS model, mice with a myeloid-specific deletion of Egfr had significantly decreased tumor multiplicity and burden, protection from high-grade dysplasia and significantly reduced colitis. Intriguingly, mice with gastrointestinal epithelial cell-specific Egfr deletion demonstrated no differences in tumorigenesis in the AOM-DSS model. The alterations in tumorigenesis in myeloid-specific Egfr knockout mice were accompanied by decreased macrophage, neutrophil and T-cell infiltration. Pro-tumorigenic M2 macrophage activation was diminished in myeloid-specific Egfr-deficient mice, as marked by decreased Arg1 and Il10 mRNA expression and decreased interleukin (IL)-4, IL10 and IL-13 protein levels. Surprisingly, diminished M1 macrophage activation was also detectable, as marked by significantly reduced Nos2 and Il1b mRNA levels and decreased interferon (IFN)-γ, tumor necrosis factor (TNF)-α and IL-1β protein levels. The alterations in M1 and M2 macrophage activation were confirmed in bone marrow-derived macrophages from mice with the myeloid-specific Egfr knockout. The combined effect of restrained M1 and M2 macrophage activation resulted in decreased production of pro-angiogenic factors, CXCL1 and vascular endothelial growth factor (VEGF), and reduced CD31+ blood vessels, which likely contributed to protection from tumorigenesis. These data reveal that EGFR signaling in macrophages, but not in colonic epithelial cells, has a significant role in CAC. EGFR signaling in macrophages may prove to be an effective biomarker of CAC or target for chemoprevention in patients with inflammatory bowel disease.

Revision of the concept of anti-angiogenesis and its applications in tumor treatment

Anti-angiogenesis therapy, by blocking formation of new blood vessels in tumors, is the standard-of-care therapy for various cancer types. The classic concept of anti-angiogenesis is expected to turn a tumor into a "dormant" disease. However, the combination of anti-angiogenesis agents with conventional therapeutics has generally produced only modest survival benefits for cancer patients in clinical trials. Therefore, the concept and applications of anti-angiogenesis have evolved dramatically along with lessons learned from recent clinical experience. In this article, we will discuss the revised concept of anti-angiogenesis therapy and the applications of anti-angiogenesis drugs, and focus particularly on how to utilize current anti-angiogenesis agents and develop new approaches to provide more benefits to patients with cancer.

Diagnostic Value of Serum Angiogenesis Markers in Ovarian Cancer Using Multiplex Immunoassay

As cancer development involves pathological vessel formation, 16 angiogenesis markers were evaluated as potential ovarian cancer (OC) biomarkers. Blood samples collected from 172 patients were divided based on histopathological result: OC (n = 38), borderline ovarian tumours (n = 6), non-malignant ovarian tumours (n = 62), healthy controls (n = 50) and 16 patients were excluded. Sixteen angiogenesis markers were measured using BioPlex Pro Human Cancer Biomarker Panel 1 immunoassay. Additionally, concentrations of cancer antigen 125 (CA125) and human epididymis protein 4 (HE4) were measured in patients with adnexal masses using electrochemiluminescence immunoassay. In the comparison between OC vs. non-OC, osteopontin achieved the highest area under the curve (AUC) of 0.79 (sensitivity 69%, specificity 78%). Multimarker models based on four to six markers (basic fibroblast growth factor-FGF-basic, follistatin, hepatocyte growth factor-HGF, osteopontin, platelet-derived growth factor AB/BB-PDGF-AB/BB, leptin) demonstrated higher discriminatory ability (AUC 0.80-0.81) than a single marker (AUC 0.79). When comparing OC with benign ovarian tumours, six markers had statistically different expression (osteopontin, leptin, follistatin, PDGF-AB/BB, HGF, FGF-basic). Osteopontin was the best single angiogenesis marker (AUC 0.825, sensitivity 72%, specificity 82%). A three-marker panel consisting of osteopontin, CA125 and HE4 better discriminated the groups (AUC 0.958) than HE4 or CA125 alone (AUC 0.941 and 0.932, respectively). Osteopontin should be further investigated as a potential biomarker in OC screening and differential diagnosis of ovarian tumours. Adding osteopontin to a panel of already used biomarkers (CA125 and HE4) significantly improves differential diagnosis between malignant and benign ovarian tumours.

Markers of Response to Antiangiogenic Therapies in Colorectal Cancer: Where Are We Now and What Should Be Next?

Despite advances in the treatment of colorectal cancer (CRC), it remains the second most common cause of cancer-related death in the Western world. Angiogenesis is a complex process that involves the formation of new blood vessels from preexisting vessels. It is essential for promoting cancer survival, growth, and dissemination. The inhibition of angiogenesis has been shown to prevent tumor progression experimentally, and several chemotherapeutic targets of tumor angiogenesis have been identified. These include anti-vascular endothelial growth factor (VEGF) treatments, such as bevacizumab (a VEGF-specific binding antibody) and anti-VEGF receptor tyrosine kinase inhibitors, although antiangiogenic therapy has been shown to be effective in the treatment of several cancers, including CRC. However, it is also associated with its own side effects and financial costs. Therefore, the identification of biomarkers that are able to identify patients who are more likely to benefit from antiangiogenic treatment is very important. This article intends to be a concise summary of the potential biomarkers that can predict or prognosticate the benefit of antiangiogenic treatments in CRC, and also what we can expect in the near future.