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

<p><b>Introduction</b>: 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.</p> <p><b>Areas covered</b>: 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.</p> <p><b>Expert commentary</b>: 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.</p

Image_1_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.jpeg

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Image_3_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.jpeg

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Aryl hydrocarbon receptor nuclear translocator-like (ARNTL/BMAL1) is associated with bevacizumab resistance in colorectal cancer via regulation of vascular endothelial growth factor A.

BACKGROUND: The identification of new biomarkers and the development of novel, targetable contexts of vulnerability are of urgent clinical need in drug-resistant metastatic colorectal cancer (mCRC). Aryl-Hydrocarbon-Receptor-Nuclear-Translocator-Like (ARNTL/BMAL1) is a circadian clock-regulated transcription factor promoting expression of genes involved in angiogenesis and tumour progression. We hypothesised that BMAL1 increases expression of the vascular endothelial growth factor A VEGFA gene and, thereby, confers resistance to anti-angiogenic therapy with bevacizumab (Beva), a clinically used antibody for neutralization of VEGFA. METHODS: PCR and immunohistochemistry were employed to assess BMAL1 expression in mice (C57BL/6 J FINDINGS: In murine CRCs, high BMAL1 expression correlated with poor preclinical response to Beva treatment. In CRC patients' tumours (n = 74), high BMAL1 expression was associated with clinical non-response to combination chemotherapy with Beva (*p = .0061) and reduced progression-free survival (PFS) [*p = .0223, Hazard Ratio (HR) = 1.69]. BMAL1 SNPs also correlated with shorter PFS (rs7396943, rs7938307, rs2279287) and overall survival (OS) [rs11022780, *p = .014, HR = 1.61]. Mechanistically, Nuclear-Receptor-Subfamily-1-Group-D-Member-1 (NR1D1/REVERBA) bound a - 672 bp Retinoic-Acid-Receptor-Related-Orphan-Receptor-Alpha-responsive-element (RORE) adjacent to a BMAL1 DNA-binding motif (E-box) in the VEGFA gene promoter, resulting in increased VEGFA synthesis and proliferation of human CRC cell lines. INTERPRETATION: BMAL1 was associated with Beva resistance in CRC. Inhibition of REVERBA-BMAL1 signalling may prevent resistance to anti-angiogenic therapy. FUND: This work was in part supported by the European Commission Seventh Framework Programme (Contract No. 278981 [ANGIOPREDICT]).</p

Image_2_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.jpeg

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Image_5_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.jpeg

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Image_4_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.jpeg

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Table_1_Case report: Complete pathologic response with first-line immunotherapy combination in a young adult with massive liver dissemination of mismatch repair–deficient metastatic colorectal cancer: Immunological and molecular profiling.docx

The current level of evidence for immunotherapy in previously untreated microsatellite unstable metastatic colorectal cancer is based on recent pieces of evidence of few studies that demonstrated durable response and clinical benefit, in terms of objective response rate, disease control rate, and progression-free survival in this subgroup of patients. On the basis of combinatorial immunotherapy with nivolumab plus ipilimumab, we report the exceptional case of a complete pathological response in a 21-year-old woman presenting a clinically aggressive stage IV colorectal cancer with massive nodal and liver involvement. Extensive molecular analyses based on whole genome next-generation DNA sequencing, RNA sequencing, fluorescent multiplex immunohistochemistry, and flow cytometry provided a detailed description of tumoral and immunological characteristics of this noteworthy clinical case.</p

Prospective Validation of Candidate SNPs of <i>VEGF/VEGFR</i> Pathway in Metastatic Colorectal Cancer Patients Treated with First-Line FOLFIRI Plus Bevacizumab

<div><p>Purpose</p><p>The potential impact of different SNPs of <i>VEGF/VEGFR</i> pathway on the clinical outcome of mCRC patients receiving bev-containing regimens has been investigated in retrospective experiences with contrasting results. We previously reported the association of <i>VEGFA</i> rs833061 C/T variants with PFS in metastatic colorectal cancer patients treated with first-line FOLFIRI plus bevacizumab. The primary objective of this work was to prospectively validate that retrospective finding. A confirmatory analysis of other SNPs of <i>VEGF/VEGFR</i> pathway genes was included.</p><p>Experimental design</p><p>To detect a HR for PFS of 1.7 for <i>VEGFA</i> rs833061 T/T compared to C- variants in metastatic colorectal cancer patients treated with first-line FOLFIRI plus bevacizumab, setting two-sided α = 0.05 and β = 0.20, 199 events were required. <i>VEGFA</i> rs699946 A/G, rs699947 A/C, <i>VEGFR1</i> rs9582036 A/C and rs7993418 A/G, <i>VEGFR2</i> rs11133360 C/T, rs12505758 C/T and rs2305948 C/T and <i>EPAS1</i> rs4145836 A/G were also tested. Germ-line DNA was extracted from peripheral blood. SNPs were analyzed by PCR and sequencing.</p><p>Results</p><p>Four-hundred-twenty-four pts were included. At the univariate analysis, no differences according to <i>VEGFA</i> rs833061 C/T variants were observed in PFS (p = 0.38) or OS (p = 0.95). Among analyzed SNPs, only <i>VEGFR2</i> rs12505758 C- variants, compared to T/T, were associated to shorter PFS (HR: 1.36 [1.05–1.75], p = 0.015, dominant genetic model) and OS, with a trend toward significance (HR: 1.34 [0.95–1.88], p = 0.088). In the multivariate model, this association retained significance (HR: 1.405 [1.082–1.825], p = 0.012) in PFS, that was lost by applying multiple testing correction (p = 0.14).</p><p>Conclusion</p><p>This prospective experience failed to validate the hypothesized predictive impact of <i>VEGFA</i> rs833061 variants. Retrospective findings on different candidate SNPs were not confirmed. Only <i>VEGFR2</i> rs12505758 variants, whose prognostic and not predictive impact was previously reported, correlated with PFS. Given the complexity of angiogenesis, it is rather unlike that a single germ-line SNP might be a good predictor of benefit from bevacizumab.</p></div

<i>VEGFA 833061</i> SNP allelic variants and survival.

*<p><i>P</i> value was based on Cochran-Mantel-Haenszel test for response and log-rank test for PFS and OS.</p