Overexpression of Both CXC Chemokine Receptor 4 and Vascular Endothelial Growth Factor Proteins Predicts Early Distant Relapse in Stage II-III Colorectal Cancer Patients

Chemokines as Prognostic Factor in Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

Chemokines orchestrate many aspects of tumorigenic processes such as angiogenesis, apoptosis and metastatic spread, and related receptors are expressed on tumor cells as well as on inflammatory cells (e.g., tumor-infiltrating T cells, TILs) in the tumor microenvironment. Expressional changes of chemokines and their receptors in solid cancers are common and well known, especially in affecting colorectal cancer patient outcomes. Therefore, the aim of this current systematic review and meta-analysis was to classify chemokines as a prognostic biomarker in colorectal cancer patients. A systematic literature search was conducted in PubMed, CENTRAL and Web of Science. Information on the chemokine expression of 25 chemokines in colorectal cancer tissue and survival data of the patients were investigated. The hazard ratio of overall survival and disease-free survival with chemokine expression was examined. The risk of bias was analyzed using Quality in Prognosis Studies. Random effects meta-analysis was performed to determine the impact on overall respectively disease survival. For this purpose, the pooled hazard ratios (HR) and their 95% confidence intervals (CI) were used for calculation. Twenty-five chemokines were included, and the search revealed 5556 publications. A total of thirty-one publications were included in this systematic review and meta-analysis. Overexpression of chemokine receptor CXCR4 was associated with both a significantly reduced overall survival (HR = 2.70, 95%-CI: 1.57 to 4.66, p = 0.0003) as well as disease-free survival (HR = 2.68, 95%-CI: 1.41 to 5.08, p = 0.0026). All other chemokines showed either heterogeneous results or few studies were available. The overall risk of bias for CXCR4 was rated low. At the current level of evidence, this study demonstrates that CXCR4 overexpression in patients with colorectal cancer is associated with a significantly diminished overall as well as disease-free survival. Summed up, this systematic review and meta-analysis reveals CXCR4 as a promising prognostic biomarker. Nevertheless, more evidence is needed to evaluate CXCR4 and its antagonists serving as new therapeutic targets.

Circulating Vitamin D Level and Its Impact on Mortality and Recurrence in Stage III Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D (VD) has been implicated in several diseases, including colorectal cancer (CRC). This study aimed to determine whether there is an association between VD levels and time-to-outcome in stage III CRC patients through a systematic review and meta-analysis.

METHODS

The study adhered to the PRISMA 2020 statement. Articles were searched in PubMed/MEDLINE and Scopus/ELSEVIER. Four articles were selected, with the primary objective of providing a pooled estimate of the risk of death specifically in stage III CRC patients based on pre-operative VD levels. Study heterogeneity and publication bias were analyzed using Tau² statistics and funnel plots.

RESULTS

The selected studies showed significant heterogeneity regarding time-to-outcome, technical assessments, and serum VD concentration measures. The pooled analysis of 2628 and 2024 patients revealed a 38% and 13% increase in the risk of death (HR: 1.38, 95% CI: 0.71-2.71) and recurrence (HR: 1.13; 95% CI: 0.84-1.53), respectively, for random-effects models among patients with lower levels of VD.

CONCLUSIONS

Our findings suggest that a low concentration of VD has a significant negative impact on time-to-outcome in stage III CRC.

Rectum to Medulla Oblongata: Colorectal Cancer Metastasizing to the Brainstem

Metastasis with colorectal cancer (CRC) is commonly seen in the liver, lungs and peritoneal cavity. Brainstem involvement with CRC is not studied with no prior reported cases. We report a case of CRC, admitted for apneic spells and dry cough and later found to have metastasis to the left anterolateral medulla oblongata. A 28-year-old male, with a past medical history of asthma, and colorectal adenocarcinoma metastatic to the brain, presented to the emergency department with complaints of a dry cough, altered mental status and shortness of breath. He was seen at urgent care before and was given a week of oral levofloxacin for presumptive pneumonia without any relief. Physical examination was concerning for stridor with clear lung fields. MRI brain showed previously noted post-operative right frontoparietal craniotomy changes and a new 9 x 8 x 8 mm ring-enhancing intra-axial lesion centered at the left anterolateral medulla oblongata indicative of brainstem metastatic disease. The patient was intubated for airway protection and underwent a suboccipital craniotomy for resection of the left pontomedullary mass, and histopathology was positive for metastatic adenocarcinoma, colorectal primary with hemorrhagic necrosis. He had a tracheostomy placed post multiple failed extubation trials and a gastrostomy tube for oral feeds. Goals of care were addressed with the patient and family, and a decision was made for home hospice.

Effects of wound infection on prognosis after laparoscopic abdominoperineal resection of rectal cancer

Background

In two facilities in Chongqing, this research sought to retrospectively evaluate the effects of perineal wound infection on survival after laparoscopic abdominoperineal resection (LAPR) of rectal cancer.

Methods

To obtain clinical information on patients who underwent LAPR between January 2013 and December 2021, we performed a multicenter cohort study. A total of 473 patients were enrolled: 314 in the non-infection group and 159 in the group with perineal infection. The general data, perioperative conditions, and tumor outcomes between groups were analyzed. The infection rates, recurrence rates, and survival rates of the two centers were compared.

Results

The age, height, weight, body mass index (BMI), preoperative complications, preoperative treatment, and intraoperative conditions of patients in the LAPR infection group were not statistically different from those in the non-infection group. The percentage of men, typical postoperative hospital stay, length of initial postoperative therapy, and recurrence and metastasis rates were all considerably higher in the infection group than those in the non-infection group. Wound infection was an independent factor affecting tumor recurrence and metastasis after LAPR as well as an independent factor shortening patient survival time according to multivariate analysis. The incidence of wound infection, the rate of recurrence, and the rate of mortality did not vary significantly across sites.

Conclusion

Wound infection after LAPR increases the mean postoperative hospital stay, prolongs the time to first postoperative treatment, and decreases the disease-free survival (DFS) and overall survival (OS). Therefore, decreasing the rate of LAPR wound infection is expected to shorten the postoperative hospital stay and prolong the patient DFS and OS. Patients with postoperative infection may require intensive adjuvant therapy.

Systematic Analysis of CXC Chemokine–Vascular Endothelial Growth Factor A Network in Colonic Adenocarcinoma from the Perspective of Angiogenesis

Background

Tumor angiogenesis plays a vital role in tumorigenesis, proliferation, and metastasis. Recently, vascular endothelial growth factor A (VEGFA) and CXC chemokines have been shown to play vital roles in angiogenesis. Exploring the expression level, gene regulatory network, prognostic value, and target prediction of the CXC chemokine-VEGFA network in colon adenocarcinoma (COAD) is crucial from the perspective of tumor angiogenesis.

Methods

In this study, we analyzed gene expression and regulation, prognostic value, target prediction, and immune infiltrates related to the CXC chemokine-VEGFA network in patients with COAD using multiple databases (cBioPortal, UALCAN, Human Protein Atlas, GeneMANIA, GEPIA, TIMER (version 2.0), TRRUST (version 2), LinkedOmics, and Metascape).

Results

Our results showed that CXCL1/2/3/5/6/8/11/16/17 and VEGFA were markedly overexpressed, while CXCL12/13/14 were underexpressed in patients with COAD. Moreover, genetic alterations in the CXC chemokine-VEGFA network found at varying rates in patients with COAD were as follows: CXCL1/2/17 (2.1%), CXCL3/16 (2.6%), CXCL5/14 (2.4%), CXCL6 (3%), CXCL8 (0.8%), CXCL11/13 (1.9%), CXCL12 (0.6%), and VEGFA (1.3%). Promoter methylation of CXCL1/2/3/11/13/17 was considerably lower in patients with COAD, whereas methylation of CXCL5/6/12/14 and VEGFA was considerably higher. Furthermore, CXCL9/10/11 and VEGFA expression was notably correlated with the pathological stages of COAD. In addition, patients with COAD with high CXCL8/11/14 or low VEGFA expression levels survived longer than patients with dissimilar expression levels. CXC chemokines and VEGFA form a complex regulatory network through coexpression, colocalization, and genetic interactions. Moreover, many transcription factor targets of the CXC chemokine-VEGFA network in patients with COAD were identified: RELA, NFKB1, ZFP36, XBP1, HDAC2, SP1, ATF4, EP300, BRCA1, ESR1, HIF1A, EGR1, STAT3, and JUN. We further identified the top three miRNAs involved in regulating each CXC chemokine within the network: miR-518C, miR-369-3P, and miR-448 regulated CXCL1; miR-518C, miR-218, and miR-493 regulated CXCL2; miR-448, miR-369-3P, and miR-221 regulated CXCL3; miR-423 regulated CXCL13; miR-378, miR-381, and miR-210 regulated CXCL14; miR-369-3P, miR-382, and miR-208 regulated CXCL17; miR-486 and miR-199A regulated VEGFA. Furthermore, the CXC chemokine-VEGFA network in patients with COAD was notably associated with immune infiltration.

Conclusions

This study revealed that the CXC chemokine-VEGFA network might act as a prognostic biomarker for patients with COAD. Moreover, our study provides new therapeutic targets for COAD, serving as a reference for further research in the future.

Chemokines and chemokine receptors in colorectal cancer; multifarious roles and clinical impact

Colorectal cancer (CRC) is considered the second cause of cancer death worldwide. The early diagnosis plays a key role in patient prognosis and subsequently overall survival. Similar to several types of cancer, colorectal cancer is also characterised by drug resistance and heterogeneity that contribute to its complexity -especially at advanced stages. However, despite the extensive research related to the identification of biomarkers associated to early diagnosis, accurate prognosis and the management of CRC patients, little progress has been made thus far. Therefore, the mortality rates, especially at advanced stages, remain high. A large family of chemoattractant cytokines called chemokines are known for their significant role in inflammation and immunity. Chemokines released by the different tumorous cells play a key role in increasing the complexity of the tumour's microenvironment. The current review investigates the role of chemokines and chemokine receptors in colorectal cancer and their potential as clinical molecular signatures that could be effectively used as a personalised therapeutic approach. We discussed how chemokine and chemokine receptors regulate the microenvironment and lead to heterogeneity in CRC. An important aspect of chemokines is their role in drug resistance which has been extensively discussed. This review also provides an overview of the current advances in the search for chemokines and chemokine receptors in CRC.

Interleukin-1 receptor antagonist inhibits matastatic potential by down-regulating CXCL12/CXCR4 signaling axis in colorectal cancer

Background

The aim of this study was to investigate the co-operative role of CXCR4/CXCL12 axis and IL-1Ra in metastatic processes mechanism by interactions between colorectal cancer cells and stromal cells in their microenvironment.

Methods

Expression of IL-1α, interleukin-1 receptor type I (IL-1 RI), CXCL12 and CXCR4 mRNA and proteins were determined by RT-PCR and Western blot. The effect of secreted level of CXCL12 by IL-1Ra on fibroblasts was measured by ELISA. CXCL12 regulate metastatic potential of colorectal cancer was evaluated by proliferation, invasion and angiogenesis assays, respectively, in which invasion and angiogenesis assays used an in vitro system consisting of co-cultured colorectal cells and stromal cells.

Results

IL-1α was expressed in high liver metastatic colorectal cancer cell lines (HT-29 and WiDr). The colorectal cancer cell-derived IL-1α and rIL-1α significantly promoted CXCL12 expression by fibroblasts, and this enhancing effect can be significantly inhibited by IL-1Ra (P < 0.01). CXCL12 not only enhanced the migration and proliferation of human umbilical vein endothelial cells, but also significantly enhanced angiogenesis (P < 0.01). Furthermore, the high liver-metastatic colorectal cancer cell line (HT-29), which secretes IL-1α, significantly enhanced angiogenesis compared to the low liver-metastatic cell line (CaCo-2), which does not produce IL-1α (P < 0.01). On the contrary, IL-1Ra can significantly inhibit migration, proliferation and angiogenesis (P < 0.01).

Conclusion

Autocrine IL-1α and paracrine CXCL12 co-enhances the metastatic potential of colorectal cancer cells; IL-1Ra can inhibit the metastatic potential of colorectal cancer cells via decrease IL-1α/CXCR4/CXCL12 signaling pathways.

Graphical Abstract

SIRT1 induces the accumulation of TAMs at colorectal cancer tumor sites via the CXCR4/CXCL12 axis

Our previous work suggested that high SIRT1 expression by cancer cells predicted a poor colorectal cancer (CRC) prognosis, but its role in the tumor microenvironment was unclear. Here, we examined tumor-infiltrating lymphocytes (TILs) in CRC expressing different levels of SIRT1. We also established a co-culture system with monocytes, CD8⁺ T cells and patient-derived tumor organoids (PDOs) to study the relationships between immune cells and cancer cells. The percentage of CD8⁺ T cells was decreased and the percentage of macrophages was increased in SIRT1-high (SIRT1-hi) CRC. Co-culture results showed that tumor-associated macrophages (TAMs) from SIRT1-hi CRC inhibited the proliferation and anti-tumor activity of CD8⁺ T cells. Importantly, SIRT1-hi CRC were shown to modulate the migration and the activity of TAMs. RNA sequencing revealed that CD14⁺ monocytes in SIRT1-hi patients expressed higher levels of CXCR4. Mechanistically, SIRT1 expression was shown to promote CXCL12 expression by inhibiting the acetylation of p53. Our findings indicate that SIRT1 in CRC induces TAM migration through the CXCR4/CXCL12 pathway, and inhibits the proliferation and activity of CD8⁺ T cells, resulting in promotion of CRC progression.

Novel diagnostic and prognostic biomarkers of colorectal cancer: Capable to overcome the heterogeneity-specific barrier and valid for global applications

Introduction

The heterogeneity-specific nature of the available colorectal cancer (CRC) biomarkers is significantly contributing to the cancer-associated high mortality rate worldwide. Hence, this study was initiated to investigate a system of novel CRC biomarkers that could commonly be employed to the CRC patients and helpful to overcome the heterogenetic-specific barrier.

Methods

Initially, CRC-related hub genes were extracted through PubMed based literature mining. A protein-protein interaction (PPI) network of the extracted hub genes was constructed and analyzed to identify few more closely CRC-related hub genes (real hub genes). Later, a comprehensive bioinformatics approach was applied to uncover the diagnostic and prognostic role of the identified real hub genes in CRC patients of various clinicopathological features.

Results

Out of 210 collected hub genes, in total 6 genes (CXCL12, CXCL8, AGT, GNB1, GNG4, and CXCL1) were identified as the real hub genes. We further revealed that all the six real hub genes were significantly dysregulated in colon adenocarcinoma (COAD) patients of various clinicopathological features including different races, cancer stages, genders, age groups, and body weights. Additionally, the dysregulation of real hub genes has shown different abnormal correlations with many other parameters including promoter methylation, overall survival (OS), genetic alterations and copy number variations (CNVs), and CD8+T immune cells level. Finally, we identified a potential miRNA and various chemotherapeutic drugs via miRNA, and real hub genes drug interaction network that could be used in the treatment of CRC by regulating the expression of real hub genes.

Conclusion

In conclusion, we have identified six real hub genes as potential biomarkers of CRC patients that could help to overcome the heterogenetic-specific barrier across different clinicopathological features.

Prognostic and Predictive Role of CXC Chemokine Receptor 4 in Metastatic Colorectal Cancer Patients

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide. About 30% of patients present with metastatic disease involving predominantly the liver and a similar percentage will develop distant metastases later after removal of the primary tumor. In metastatic CRC, chemotherapies and biological drugs have prolonged survival for up to 30 months. However, there is a great need for biomarkers predictive of response and prognosis to optimize treatments. CXC chemokine receptor 4 (CXCR4) is a chemokine receptor; it binds to CXCL12 and plays a central role in colon cancer cells' growth and dissemination.

MATERIALS AND METHODS

CXCR4 was evaluated in CRC primary tissues by immunohistochemistry. Formalin-fixed, paraffin-embedded 4-μm tissue sections were immunostained using a biotin-streptavidin-peroxidase method and categorized into 2 semiquantitative classes: (i) absence of staining, ≤50% positive cells (negative/low) and (ii) >50% positive cells (high). Associations between clinic-pathologic variables and CXCR4 expression were evaluated using the χ test. The Kaplan-Meier product-limit method was applied to graph overall survival (OS). OS was defined as the time elapsed from diagnosis to death from any cause. Univariate analysis was carried out using the log-rank test. Cox proportional hazards regression was used to analyze the effect of several risk factors on OS.

RESULTS

Seventy-eight primary adenocarcinomas were analyzed; 26 were categorized as negative/low and 52 as high. Age, sex, performance status, site of metastases, KRAS mutational status, type of first-line therapy, and a number of therapy lines did not correlate with CXCR4 expression. Although not significant (P=0.0533), high CXCR4 expression was more frequently localized on the right side of the colon. Significant correlations were detected with grading (P=0.0041) and response to first-line anti-epidermal growth factor receptors agents (P<0.0001), bevacizumab (P=0.0029), and chemotherapy alone (P=0.0260). At a median follow-up of 53 months, 77 deaths have been registered. Grading [hazard ratio (HR): 1.42; confidence interval (CI): 0.89-2.28; P<0.0001], KRAS mutational status (HR: 1.73; CI: 1.03-290; P=0.0133), response to first-line chemotherapy (HR: 3.39; CI: 2.10-5.48; P<0.0001), and CXCR4 expression (HR: 3.18; CI: 2.01-5.02; P<0.0001) showed prognostic power at univariate and multivariate analyses.

CONCLUSION

In the present report, we show that CXCR4 expression on the primary tumor is an independent prognostic factor and correlates with response to first-line chemotherapy in metastatic CRC patients.

Prognostic Significance of CXCR4 in Colorectal Cancer: An Updated Meta-Analysis and Critical Appraisal

Simple Summary

C-X-C chemokine receptor type 4 (CXCR4), a G-protein-coupled receptor, has been demonstrated to stimulate proliferation and invasiveness of many different tumors, including colorectal cancer. Through in vitro evidence, overexpression of CXCR4 has been identified as a negative prognostic factor in colorectal cancer. The identification of prognostic biomarkers can improve the prediction of disease evolution and disease characterization, and guide treatment efforts. This systematic review with a meta-analysis was conducted to pool hazard ratios from prognostic studies on CXCR4, provide an updated estimate of prognostic power of CXCR4, and analyze modalities of evaluating and reporting CXCR4 expression.

Abstract

Background: This study was conducted to provide an updated estimate of the prognostic power of C-X-C chemokine receptor type 4 (CXCR4) in colorectal cancer (CRC), and analyze modalities of evaluating and reporting its expression. Methods: A systematic review with meta-analysis was performed and described according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Studies were identified through PubMed and Google Scholar. The pooled hazard ratios (HRs) for overall survival (OS) or progression-free survival (PFS) with 95% confidence interval (CI) were estimated with the random-effect model. Results: Sixteen studies were selected covering a period from 2005 to 2020. An immunohistochemical evaluation of CXCR4 was performed in all studies. Only in three studies assessment of mRNA through RT–PCR was correlated with prognosis; in the remaining studies, the authors identified prognostic categories based on immunohistochemical expression. In pooled analyses, significant associations were found between positive or high or strong expression of CXCR4 and T stage ≥3 (P = 0.0001), and positive or high or strong expression of CXCR4 and left side primary tumor localization (P = 0.0186). The pooled HR for OS was 2.09 (95% CI: 1.30–2.88) in favor of high CXCR4 expression; for PFS, it was 1.42 (95% CI: 1.13–1.71) in favor of high CXCR4 expression. Conclusion: High CXCR4 expression is clearly associated with increased risk of death and progression in CRC. However, strong methodologic heterogeneity in CXCR4 assessment hinders direct translation into clinical practice; thus, a consensus to streamline detection and scoring of CXCR4 expression in CRC is indicated.

Circulating Biomarkers of Colorectal Cancer (CRC)-Their Utility in Diagnosis and Prognosis

The global burden of colorectal cancer (CRC) is expected to increase, with 2.2 million new cases and 1.1 million annual deaths by 2030. Therefore, the establishment of novel biomarkers useful in the early diagnosis of CRC is of utmost importance. A number of publications have documented the significance of the overexpression of several specific proteins, such as inflammatory mediators, in CRC progression. However, little is known about the potential utility of these proteins as circulating blood tumor biomarkers of CRC. Therefore, in the present review we report the results of our previous original studies as well as the findings of other authors who investigated whether inflammatory mediators might be used as novel biomarkers in the diagnosis and prognosis of CRC. Our study revealed that among all of the tested proteins, serum M-CSF, CXCL-8, IL-6 and TIMP-1 have the greatest value in the diagnosis and progression of CRC. Serum TIMP-1 is useful in differentiating between CRC and colorectal adenomas, whereas M-CSF and CRP are independent prognostic factors for the survival of patients with CRC. This review confirms the promising significance of these proteins as circulating biomarkers for CRC. However, due to their non-specific nature, further validation of their sensitivity and specificity is required.

CXCL12 Signaling in the Tumor Microenvironment

Tumor microenvironment (TME) is the local environment of tumor, composed of tumor cells and blood vessels, extracellular matrix (ECM), immune cells, and metabolic and signaling molecules. Chemokines and their receptors play a fundamental role in the crosstalk between tumor cells and TME, regulating tumor-related angiogenesis, specific leukocyte infiltration, and activation of the immune response and directly influencing tumor cell growth, invasion, and cancer progression. The chemokine CXCL12 is a homeostatic chemokine that regulates physiological and pathological process such as inflammation, cell proliferation, and specific migration. CXCL12 activates CXCR4 and CXCR7 chemokine receptors, and the entire axis has been shown to be dysregulated in more than 20 different tumors. CXCL12 binding to CXCR4 triggers multiple signal transduction pathways that regulate intracellular calcium flux, chemotaxis, transcription, and cell survival. CXCR7 binds with high-affinity CXCL12 and with lower-affinity CXCL11, which binds also CXCR3. Although CXCR7 acts as a CXCL12 scavenger through ligand internalization and degradation, it transduces the signal mainly through β-arrestin with a pivotal role in endothelial and neural cells. Recent studies demonstrate that TME rich in CXCL12 leads to resistance to immune checkpoint inhibitors (ICI) therapy and that CXCL12 axis inhibitors sensitize resistant tumors to ICI effect. Thus targeting the CXCL12-mediated axis may control tumor and tumor microenvironment exerting an antitumor dual action. Herein CXCL12 physiology, role in cancer biology and in composite TME, prognostic role, and the relative inhibitors are addressed.

Chemokines-What Is Their Role in Colorectal Cancer?

Colorectal cancer (CRC) is one of the leading causes of cancer-related death. It is the second most frequently diagnosed malignancy in Europe and third worldwide. Colorectal malignancies diagnosed at an early stage offer a promising survival rate. However, advanced tumors often present distant metastases even after the complete resection of a primary tumor. Therefore, novel biomarkers of CRC are sorely needed in the diagnosis and prognosis of this common malignancy. A family of chemokines are composed of small, secreted proteins. They are best known for their ability to stimulate the migration of several cell types. Some investigations have indicated that chemokines are involved in cancer development, including CRC. This article presents current knowledge regarding chemokines and their specific receptors in CRC progression. Moreover, the prime aim of this review is to summarize the potential role of these proteins as biomarkers in the diagnosis and prognosis of CRC.

New CXCR4 Antagonist Peptide R (Pep R) Improves Standard Therapy in Colorectal Cancer

The chemokine receptor CXCR4 is overexpressed and functional in colorectal cancer. To investigate the role of CXCR4 antagonism in potentiating colon cancer standard therapy, the new peptide CXCR4 antagonist Peptide R (Pep R) was employed. Human colon cancer HCT116 xenograft-bearing mice were treated with chemotherapeutic agents (CT) 5-Fluorouracil (5FU) and oxaliplatin (OX) or 5FU and radio chemotherapy (RT-CT) in the presence of Pep R. After two weeks, CT plus Pep R reduced by 4-fold the relative tumor volume (RTV) as compared to 2- and 1.6-fold reductions induced, respectively, by CT and Pep R. In vitro Pep R addition to CT/RT-CT impaired HCT116 cell growth and further reduced HCT116 and HT29 clonal capability. Thus, the hypothesis that Pep R could target the epithelial mesenchyme transition (EMT) process was evaluated. While CT decreased ECAD and increased ZEB-1 and CD90 expression, the addition of Pep R restored the pretreatment expression. In HCT116 and HT29 cells, CT/RT-CT induced a population of CD133+CXCR4+ cells, supposedly a stem-resistant cancer cell population, while Pep R reduced it. Taken together, the results showed that targeting CXCR4 ameliorates the effect of treatment in colon cancer through inhibition of cell growth and reversal of EMT treatment-induced markers, supporting further clinical studies.

Chemokine receptor 4 targeted protein MRI contrast agent for early detection of liver metastases

Liver metastases often progress from primary cancers including uveal melanoma (UM), breast, and colon cancer. Molecular biomarker imaging is a new non-invasive approach for detecting early stage tumors. Here, we report the elevated expression of chemokine receptor 4 (CXCR4) in liver metastases in UM patients and metastatic UM mouse models, and development of a CXCR4-targeted MRI contrast agent, ProCA32.CXCR4, for sensitive MRI detection of UM liver metastases. ProCA32.CXCR4 exhibits high relaxivities (r ₁ = 30.9 mM^-1 s^-1, r ₂ = 43.2 mM^-1 s^-1, 1.5 T; r ₁ = 23.5 mM^-1 s^-1, r ₂ = 98.6 mM^-1 s^-1, 7.0 T), strong CXCR4 binding (K _d = 1.10 ± 0.18 μM), CXCR4 molecular imaging capability in metastatic and intrahepatic xenotransplantation UM mouse models. ProCA32.CXCR4 enables detecting UM liver metastases as small as 0.1 mm³. Further development of the CXCR4-targeted imaging agent should have strong translation potential for early detection, surveillance, and treatment stratification of liver metastases patients.

CXCR4/TGF-β1 mediated hepatic stellate cells differentiation into carcinoma-associated fibroblasts and promoted liver metastasis of colon cancer

Background: Liver metastasis of colon cancer is strongly affected by the tumor microenvironment (TME), with interactions between tumor cells and cancer-associated fibroblasts (CAFs) in particular. TGF-β is well known for its ability to mediate the CAF phenotype, and CXCR4 expression is closely correlated to poor prognosis in CRC. The relationship between these two signaling pathways remains to be delineated in liver metastasis of colon cancer.Methods: Immunohistochemistry was employed to investigate CXCR4 expression in 45 human specimens of primary colorectal cancer (CRC) and liver metastasis. The functions of SDF-1 released by hepatic stellate cells (HSCs) on CXCR4 and TGF-β1 in CRC cells were investigated in vitro. The effects of CRC on HSCs differentiation into CAFs were confirmed using co-culture technology and expression analysis of CAFs markers by qPCR, western blot and immunofluorescence. The involvement of CXCR4 and TGF-β1 was verified with addition of CXCR4 inhibitor AMD3100 and TGF-β1 inhibitor cyclophosphamide (Cy) both in vitro and in vivo.Results: There were more CXCR4-positive cells at the liver metastatic tissues compared to the primary sites. CRC cells activated and transformed HSCs to CAFs after co-cultivating with HSCs. Activated HSCs stimulated TGF-β1 secretion from CRC cells after co-culture with CRC cells in vitro. Moreover, the expression of CAFs markers was increasing in the activated HSCs. In a mouse hepatic metastasis model, treated with AMD3100 or Cy blocked the metastatic potential of HCT116 cells and the hepatic CAFs differentiation.Conclusions: These results indicated that CXCR4/TGF-β1 axis plays an important role in CRC liver metastasis through mediating HSCs differentiation into CAFs, providing preclinical evidences that blockade of the axis might be beneficial for anti-metastasis therapy in CRC.

A Phase Ib/II Trial of the First-in-Class Anti-CXCR4 Antibody Ulocuplumab in Combination with Lenalidomide or Bortezomib Plus Dexamethasone in Relapsed Multiple Myeloma

PURPOSE

Ulocuplumab (BMS-936564) is a first-in-class fully human IgG4 monoclonal anti-CXCR4 antibody that inhibits the binding of CXCR4 to CXCL12.

PATIENTS AND METHODS

This phase Ib/II study aimed to determine the safety and tolerability of ulocuplumab alone and in combination with lenalidomide and dexamethasone (Arm A), or bortezomib and dexamethasone (Arm B), in patients with relapsed/refractory multiple myeloma.

RESULTS

Forty-six patients were evaluated (median age, 60 years; range, 53-67). The median number of prior therapies was 3 (range, 1-11), with 70% of subjects having received ≥3. This trial had a dose-escalation and a dose-expansion part. Using a 3+3 design on both arms of the trial, ulocuplumab's dose was escalated to a maximum of 10 mg/kg without reaching MTD. The most common treatment-related adverse events (AE) were neutropenia (13 patients, 43.3%) in Arm A and thrombocytopenia (6 patients, 37.5%) in Arm B. No deaths related to study drugs occurred. The combination of ulocuplumab with lenalidomide and dexamethasone showed a high response rate (PR or better) of 55.2% and a clinical benefit rate of 72.4%, even in patients who had been previously treated with immunomodulatory agents (IMiD).

CONCLUSIONS

This study showed that blockade of the CXCR4-CXCL12 axis by ulocuplumab is safe with acceptable AEs and leads to a high response rate in combination with lenalidomide and dexamethasone in patients with relapsed/refractory myeloma, making CXCR4 inhibitors a promising class of antimyeloma drugs that should be further explored in clinical trials.

Fibroblast-derived CXCL12 regulates PTEN expression and is associated with the proliferation and invasion of colon cancer cells via PI3k/Akt signaling

Background

Stromal-derived CXCL12 play an important role which influence the proliferation and invasiveness of colon cancer in microenvironment. The present study aimed to analyze the underlying mechanism by which CXCL12 and tumour suppressor protein phosphatase and tensin homologue deleted on chromosome 10 (PTEN) influences the metastatic potential of colon cancer and internal relation of colon cancer and stromal cells.

Methods

RT-PCR and western blot were detected the expression of CXCL12, CXCR4 and PTEN in colon cancer cells and stromal cells. The co-operative effects of CXCL12 and PTEN on proliferation and invasion of colon cancer cells were evaluated by real-time PCR, proliferation and invasion assays using an in vitro system consisting of co-cultured cancer cells and stromal cells. We eventually investigated activation of PI3K/Akt signaling by CXCL12 regulate PTEN and involved in the metastatic process of colon cancer. In addition, we also examine how the knockdown of PTEN influences proliferation and invasion and correlate with CXCL12/CXCR4/PI3K/Akt, determination of PTEN up-down-stream targets that preferentially contribute to tumorigenesis.

Results

Blockage of PTEN phosphorylation led to a stronger enhancement of cell proliferation and invasion upon stimulation with CXCL12 via its activation of the PI3K/Akt signaling pathway. Furthermore, knockdown of PTEN by siRNA transfection was also found to enhance the activation of the PI3K/Akt pathway, thereby promoting cell invasion and proliferation. CXCL12 induced transcriptional down-regulation of activated PTEN and this signaling pathway promotes cell survival. CXCL12/CXCR4/PI3K/Akt cascade may be critical for colon cancer cells to metastasize.

Conclusions

Based on our results, we suggest that the modification of CXCR4, PTEN, or PI3K function might be promising new therapeutic approaches to inhibit the aggressive spread of colon cancer.

Development and validation of an immunity-related classifier of nine chemokines for predicting recurrence in stage I-III patients with colorectal cancer after operation

Introduction

Chemokines are closely related with tumor immunity, progression, and metastasis. We aimed to construct a multi-RNA classifier of chemokine family genes for predicting tumor recurrence in stage I-III patients with colorectal cancer (CRC) after operation.

Patients and methods

By analyzing microarray data, the Cox regression analysis was conducted to determine survival-related chemokine family genes and develop a multi-RNA classifier in the training set. The prognostic value of this multi-RNA classifier was further validated in the internal validation and external independent sets. Receiver operating characteristic curves were used to compare the prediction ability of the combined model of this multi-RNA classifier and stage, and this multi-RNA classifier and stage alone.

Results

Nine survival-related chemokines were identified in the training set. We identified a nine-chemokine classifier and classified the patients as high-risk or low-risk. Compared with CRC patients with high-risk scores, CRC patients with low-risk scores had longer disease-free survival in the training (HR=2.353, 95% CI=1.480-3.742, P<0.001), internal validation (HR=2.389, 95% CI=1.428-3.996, P<0.001), and external independent (HR=3.244, 95% CI=1.813-5.807, P<0.001) sets. This nine-chemokine classifier was an independent prognostic factor in these datasets (P<0.05). The combined model of this nine-chemokine classifier and tumor stage may tend to have higher accuracy than stage alone in the training (area under curve 0.727 vs 0.626, P<0.01), internal validation (0.668 vs 0.584, P=0.03), and external independent (0.704 vs 0.678, P>0.05) sets. This nine-chemokine classifier may only be applied in Marisa's C2, C5, and C6 subtypes patients.

Conclusion

Our nine-chemokine classifier is a reliable prognostic tool for some specific biological subtypes of CRC patients. It might contribute to guide the personalized treatment for high-risk patients.

Clinicopathologic Significance of CXCL12 and CXCR4 Expressions in Patients with Colorectal Cancer

Background

Colorectal cancer (CRC) is both a global and national burden, being the third most common malignancy in men and the second in women, worldwide. The prognosis of CRC is affected by various factors like the histological grade, angiolymphatic invasion, and distant metastases. Metastasis is an intricate process; one of the possible mechanisms is through the interaction of the chemokines CXCL12 and CXCR4. This study aims to reveal the expression patterns of CXCL12 and CXCR4 in CRC.

Methods

The quantitative expressions of CXCL12 and CXCR4 messenger RNA (mRNA) were evaluated in 32 patients with adenocarcinoma-type CRC. Real-time polymerase chain reaction (qRT-PCR) was performed on formalin-fixed tissues. CXCL12 and CXCR4's expressions, clinicopathologic features, and the treatment response to the CRC were analysed.

Results

All tumour tissues showed higher levels of both chemokines compared to normal colonic tissue. The expression of CXCL12 mRNA was higher in rectal location (p = 0.04) with a tendency to be higher in later stages (p = 0.15), while the expression of CXCR4 was lower in tumours with a lymphatic invasion (p = 0.02), compared to their counterparts. There was no difference in the expression of CXCL12 and CXCR4 according to the patients' ages, gender, tumour differentiation, or response to chemotherapy.

Conclusion

Our study demonstrated that the mRNA expression of CXCL12 was significantly correlated with rectal location. CXCR4 mRNA expression was inversely correlated in tumours with a lymphatic invasion.

Knockdown of CXCR4 Inhibits CXCL12-Induced Angiogenesis in HUVECs through Downregulation of the MAPK/ERK and PI3K/AKT and the Wnt/β-Catenin Pathways

CXCL12 is an extracellular chemokine binding to cell surface receptor CXCR4. We found that activation of CXCL12/CXCR4 axis stimulated angiogenesis in endothelial cells. Knockdown of CXCR4 in endothelial cells prevented the branch points of angiogenesis. Endothelial cells exposed to CXCL12 presented high level of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and matrix metalloproteinase MMP-2, but not in CXCR4 knockdown cells. Further studies revealed that activation of CXCL12/CXCR4 axis in vascular endothelial cells stimulates the angiogenesis through upregulation of the MAPK/ERK and PI3K/AKT and Wnt/β-catenin pathways. Conclusion, downregulation of CXCR4 could inhibit angiogenesis in cancer tissues.

CXCL12 gene silencing down-regulates metastatic potential via blockage of MAPK/PI3K/AP-1 signaling pathway in colon cancer

Background

To investigate the effect of CXCL12 gene silencing on proliferation,invasion, angiogenesis and the relationship of MAPK/PI3K/AP-1 signaling pathway in colon cancer cells.

Methods

RT-PCR and Western-blot were used to detect the expression of CXCL12 mRNA and protein in four colon cancer cell lines. Human colon cancer cells were transfected with CXCL12 siRNA carrying by Lipofectamine 2000. The expression of CXCL12 protein was confirmed by immunoblotting. WST-1, invasion and angiogenesis assay were used to examine the effect on proliferation, invasion and angiogenesis in colon cancer cells after CXCL12 siRNA silence, respectively. The phosphorylation of MAPK/PI3K/AP-1 protein levels was detected by Western blotting in CXCL12 siRNA suppression DLD-1 cell.

Results

CXCL12 mRNA and proteins were only expressed in DLD-1 colon cancer cell lines. CXCL12 siRNA were transfected into DLD-1 cells, the expression CXCL12 proteins was significantly inhibited (P < 0.01), and the proliferation, invasion and angiogenesis of DLD-1 cells were inhibited significantly (P < 0.01). CXCL12 gene silencing resulted in blockage of MAPK, PI3K and AP-1 phosphorylation by CXCL12-induced in DLD-1 colon cancer cell.

Conclusion

The silencing CXCL12 gene significantly inhibits the proliferation, invasion and angiogenesis ability of some types colon carcinoma cells through down-regulation of MAPK/PI3K/AP-1 signaling pathway.

Correlation between CXCR4/CXCR7/CXCL12 chemokine axis expression and prognosis in lymph-node-positive lung cancer patients

The CXCR4/CXCR7/CXCL12 chemokine axis plays important roles in the migration of tumor cells during cancer development by modulating site‐specific distant metastasis including to regional lymph nodes. We investigated the correlation of these chemokine expressions to prognosis in lymph‐node‐positive non‐small‐cell lung cancer (NSCLC) patients. A total of 140 surgically resected specimens of primary site (PS) and metastatic lymph nodes (MLN) of NSCLC involving hilar and/or mediastinal lymph nodes (N1‐2) were collected. CXCR4, CXCR7 and CXCL12 expressions were evaluated. Cox regression analysis was performed to determine whether these chemokines were independent prognostic factors in N1‐2 NSCLC. High expression of CXCR4 in PS and CXCL12 in MLN was associated with poor overall survival (OS) (P = .025 and .033, respectively). Significant correlations between CXCR4 expression in PS and CXCL12 expression in MLN were observed (P = .040). There was significant difference in OS between 2 groups according to expressions of CXCR4 in PS and CXCL12 in MLN (P = .0033). Expression of CXCL12 in MLN was identified as an independent prognostic factor (HR 1.79, 95% CI 1.08‐3.04, P = .023). CXCL12 in MLN was mainly expressed by tumor cells compared with stromal cells (56% vs 25%, respectively, P < .0001). CXCR4/CXCL12 may play roles in tumor progression in MLN and is associated with poor prognosis of lymph‐node‐positive NSCLC patients.

Tudor-SN protein expression in colorectal cancer and its association with clinical characteristics

Objectives

Tudor-SN protein (SND1) is known to be up-regulated in some types of human malignancies and functions as an oncogene. The objective of our study was to investigate the expression and prognostic value of SND1 in human colorectal cancer (CRC).

Methods

Real-time PCR and western blot were performed to examine the SND1 expression in human CRC and their corresponding non-cancerous colon tissues from 42 patients. Its clinical significance was evaluated by analyzing its expression with multiple pathological characters of CRC patients. Finally, a Kaplan-Meier survival curve was derived for SND1 gene expression among these CRC patients.

Results

We found a significantly increased expression of SND1 mRNA and protein in tissue samples of CRC when compared to those in the paired normal adjacent colon tissues. High SND1 expression was positively correlated with higher tumor grades, aggressive N1+N2 nodal status and poor differentiation. Additionally, the overall survival rate in CRC patients with higher expression of SND1 was significantly shorter than that with lower SND1 expression.

Conclusion

Our findings suggested that SND1 might act as an important agent in the CRC carcinogenesis and predicted worse outcomes. The high expression of SND1 could be used as a novel predictive and prognostic marker of CRC.

microRNA-1297 Inhibits the Growth and Metastasis of Colorectal Cancer by Suppressing Cyclin D2 Expression

microRNAs (miR) can potentially be used for categorizing the various subtypes of colorectal cancer (CRC) and predicting a patient's response to treatment with traditional anti-CRC therapies. We investigated how miR-1297 and its potential target molecule cyclin D2 (CCND2) might affect the progression of CRC. Thirty-two pairs of CRC specimens and corresponding samples of para-tumor tissue were collected and examined for their levels of miR-1297 and CCND2 expression. We also examined miR-1297 and CCND2 expression in cultured SW480 cells. The effects of modulated levels of miR-1297 and CCND2 on cell viability, anchorage-independent growth ability, proliferation, apoptosis, cell cycle distribution, migration, and invasion were detected using specific techniques. The possible regulatory effect of miR-1297 on CCND2 was investigated using dual luciferase assays. Our results showed that miR-1297 expression was downregulated in clinical CRC specimens, and such downregulation was associated with upregulated levels of CCND2 expression. Upregulation of miR-1297 and downregulation of CCND2 reduced the proliferation and metastasis potential of SW480 cells, but did not affect the apoptotic process. In addition, miR-1297 regulated CCND2 function by directly binding to the promoter sequence of the CCND2 gene, which would block CCND2-related signaling at the transcription level. Our findings validate the anti-CRC function of miR-1297 and pro-CRC function of CCND2. Our findings may assist in developing miR-based therapies against CRC.

Downregulation of miR-186 is associated with metastatic recurrence of gastrointestinal stromal tumors

Although dysregulation of microRNAs (miRNAs/miRs) is a common feature of human malignancies, its involvement in gastrointestinal stromal tumors (GISTs) is not fully understood. The present study aimed to identify the miRNAs that perform a role in GIST metastasis. miRNA expression profiles from a series of 32 primary GISTs were analyzed using microarrays, and miR-186 was observed to be downregulated in tumors exhibiting metastatic recurrence. Reverse transcription-quantitative polymerase chain reaction analysis of an independent cohort of 100 primary GISTs revealed that low miR-186 expression is associated with metastatic recurrence and a poor prognosis. Inhibition of miR-186 in GIST-T1 cells promoted cell migration. Gene expression microarray analysis demonstrated that miR-186 inhibition upregulated a set of genes implicated in cancer metastasis, including insulin-like growth factor-binding protein 3, AKT serine/threonine kinase 2, hepatocyte growth factor receptor, CXC chemokine receptor 4 and epidermal growth factor-containing fibulin-like extracellular matrix protein 1. These results suggest that the downregulation of miR-186 is involved in the metastatic recurrence of GISTs, and that miR-186 levels could potentially be a predictive biomarker for clinical outcome.

Knockdown of long non-coding RNA prostate cancer-associated ncRNA transcript 1 inhibits multidrug resistance and c-Myc-dependent aggressiveness in colorectal cancer Caco-2 and HT-29 cells

The long non-coding RNA (lncRNA) prostate cancer-associated ncRNA transcript 1 (PCAT-1) has been shown to promote prostate cancer cell proliferation through c-Myc and is associated with the poor prognosis of CRC patients. In the current study, it was hypothesized that the effect of PCAT-1 on the aggressiveness of CRC cells was dependent on the function of c-Myc. Human CRC cell lines Caco-2 and HT-29 were transfected with specific PCAT-1 shRNAs, and cell migration, invasiveness, and resistance to 5-fluorouracil were measured. To elucidate the role of c-Myc in PCAT-1 function, c-Myc was overexpressed in PCAT-1-silenced CRC cells and the effect of c-Myc overexpression on the aggressiveness of PCAT-1-silenced cells was detected. The results showed that knockdown of PCAT-1 in CRC cells suppressed cell motility and invasiveness, and sensitized the cells to 5-fluorouracil, as evidenced by the reduced viability and induced apoptosis in PCAT-1-silenced cells compared to the parental cells in response to 5-fluorouracil treatment. The expression of c-Myc in PCAT-1-silenced CRC cells was down-regulated, and forced expression of c-Myc partially restored the invasiveness in PCAT-1-silenced cells. In summary, the findings outlined in the current study suggest that PCAT-1 regulates the invasiveness and drug resistance in CRC cells and that PCAT-1 may promote CRC cell invasion by modulating the expression of c-Myc.

[Impact of preoperative drug therapy on the expression of angiogenesis markers in colorectal liver metastases]

AIM

to study changes in the expression of angio- and vasculogenesis markers in colorectal adenocarcinoma metastases to the liver during combined cytotoxic and targeted anti-VEGF therapy versus cytotoxic monotherapy.

SUBJECTS AND METHODS

Intraoperative samples from 96 patients with colorectal adenocarcinomas metastases to the liver were immunohistochemically examined. The investigation enrolled patients who had preoperatively received either combined FOLFOX6 cytotoxic therapy and targeted anti-VEGF therapy with bevacizumab or only FOLFOX6 therapy, as well as patients who had not received preoperative anti-tumor drug treatment. The expression of SDF1α, CXCR4, CXCR7, and VEGF-A was compared in these groups. Statistical significance was accepted at p<0.05.

RESULTS

The expression of CXCR4 in the vessel endothelial cells was significantly less frequently detected in the patients who had received combined cytotoxic therapy and targeted anti-VEGF therapy as compared to those had not drug therapy. Comparing the patients treated with cytotoxic drugs with those who had not received anti-tumor therapy revealed similar results in the women. CXCR7 expression in the tumor cells and stromal cells from the metastatic foci was significantly more common in the group of male patients treated with cytotoxic drugs according to the FOLFOX6 regimen. The expression of SDF1α in the tumor cells was significantly more often observed in the male patients who had received combined cytotoxic therapy and targeted anti-VEGF therapy than in those who had not drug therapy. VEGF expression in the stromal cells was significantly less frequently seen in the patients who had received the combined therapy.

CONCLUSION

Combined cytotoxic therapy and targeted anti-VEGF therapy for colorectal adenocarcinoma metastases to the liver leads to some suppression of the alternative pathway in the formation of new vessels, by reducing the expression of CXCR4 in the vessel endothelial cells and that of VEGF in the stromal cells from the metastatic foci. In men, this therapy simultaneously causes an increase in the expression of SDF1α in the tumor cells and in that of CXCR4 in the stroma. Preoperative FOLFOX6 therapy significantly increases the expression of CXCR7 in the tumor cells and stromal cells in the male patients, which may suggest that this pathway in vessel formation can be activated.

Long non-coding RNAs in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Despite substantial progress in understanding the molecular mechanisms and treatment of CRC in recent years, the overall survival rate of CRC patients has not improved dramatically. The development of CRC is multifactor and multistep processes, in which abnormal gene expression may play an important role. With the advance of human tumor molecular biology, a series of studies have highlighted the role of long non-coding RNAs (lncRNAs) in the development of CRC. CRC-related lncRNAs have been demonstrated to regulate the genes by various mechanisms, including epigenetic modifications, lncRNA-miRNA and lncRNA-protein interactions, and by their actions as miRNA precursors or pseudogenes. Since some lncRNAs can be detected in human body fluid and have good specificity and accessibility, they have been suggested to be used as novel potential biomarkers for CRC diagnosis and prognosis as well as in the prediction of the response to therapy. Therefore, in this review, we will focus on lncRNAs in CRC development, the mechanisms and biomarkers of lncRNAs in CRC.

CXCR4-CXCL12-CXCR7, TLR2-TLR4, and PD-1/PD-L1 in colorectal cancer liver metastases from neoadjuvant-treated patients

A neoadjuvant clinical trial was previously conducted in patients with resectable colorectal cancer liver metastases (CRLM). At a median follow up of 28 months, 20/33 patients were dead of disease, 8 were alive with disease and 5 were alive with no evidence of disease. To shed further insight into biological features accounting for different outcomes, the expression of CXCR4-CXCL12-CXCR7, TLR2-TLR4, and the programmed death receptor-1 (PD-1)/programmed death-1 ligand (PD-L1) was evaluated in excised liver metastases. Expression profiles were assessed through qPCR in metastatic and unaffected liver tissue of 33 CRLM neoadjuvant-treated patients. CXCR4 and CXCR7, TLR2/TLR4, and PD-1/PD-L1 mRNA were significantly overexpressed in metastatic compared to unaffected liver tissues. CXCR4 protein was negative/low in 10/31, and high in 21/31, CXCR7 was negative/low in 16/31 and high in 15/31, CXCL12 was negative/low in 14/31 and high in 17/31 CRLM. PD-1 was negative in 19/30 and positive in 11/30, PD-L1 was negative/low in 24/30 and high in 6/30 CRLM. Stromal PD-L1 expression, affected the progression-free survival (PFS) in the CRLM population. Patients overexpressing CXCR4 experienced a worse PFS and cancer specific survival (CSS) (p = 0.001 and p = 0.0008); in these patients, KRAS mutation identified a subgroup with a significantly worse CSS (p < 0.01). Thus, CXCR4 and PD-L1 expression discriminate patients with the worse PFS within the CRLM evaluated patients. Within the CXCR4 high expressing patients carrying Mut-KRAS in CRLM identifies the worst prognostic group. Thus, CXCR4 targeting plus anti-PD-1 therapy should be explored to improve the prognosis of Mut-KRAS-high CXCR4-CRLMs.

Exploring the N-Terminal Region of C-X-C Motif Chemokine 12 (CXCL12): Identification of Plasma-Stable Cyclic Peptides As Novel, Potent C-X-C Chemokine Receptor Type 4 (CXCR4) Antagonists

We previously reported the discovery of a CXCL12-mimetic cyclic peptide (2) as a selective CXCR4 antagonist showing promising in vitro and in vivo anticancer activity. However, further development of this peptide was hampered by its degradation in biological fluids as well as by its low micromolar affinity for the receptor. Herein, extensive chemical modifications led to the development of a new analogue (10) with enhanced potency, specificity, and plasma stability. A combined approach of Ala-amino acid scan, NMR, and molecular modeling unraveled the reasons behind the improved binding properties of 10 vs 2. Biological investigations on leukemia (CEM) and colon (HT29 and HCT116) cancer cell lines showed that 10 is able to impair CXCL12-mediated cell migration, ERK-phosphorylation, and CXCR4 internalization. These outcomes might pave the way for the future preclinical development of 10 in CXCR4 overexpressing leukemia and colon cancer.

γ-Tocotrienol suppresses growth and sensitises human colorectal tumours to capecitabine in a nude mouse xenograft model by down-regulating multiple molecules

Background:

Colorectal cancer (CRC) is one of the most common malignancies worldwide and even develops resistance to chemotherapeutic agents over time. As a result survival for patients with CRC remains poor.

Method:

We investigated both in vitro and in vivo effects of γ-tocotrienol (γ-T3) alone and in combination with capecitabine. Apoptosis and cytotoxicity assays were performed by MTT and FACS analysis, whereas expression of proteins was investigated using western blotting and immunohistochemistry.

Results:

The γ-T3 inhibited the proliferation of CRC cells with wild-type or mutated KRAS. It also induced apoptosis, inhibited colony formation, and suppressed key regulators of cell survival, cell proliferation, invasion, angiogenesis, and metastasis. Furthermore, γ-T3 enhanced the anticancer effects of capecitabine in CRC cells. In a nude mouse xenograft model of human CRC, oral administration of γ-T3 inhibited tumour growth and enhanced the antitumour efficacy of capecitabine. Western blot and immunohistochemical analysis results indicated that expression of Ki-67, cyclin D1, MMP-9, CXCR4, NF-κB/p65, and VEGF was lower in tumour tissue from the combination treatment group. Combination treatment also downregulated NF-κB and NF-κB-regulated gene products.

Conclusions:

Our findings suggest that γ-T3 inhibited the growth of human CRC and sensitised CRC to capecitabine by regulating proteins linked to tumourigenesis.

A New Anti-CXCR4 Antibody That Blocks the CXCR4/SDF-1 Axis and Mobilizes Effector Cells

The type IV C-X-C-motif chemokine receptor (CXCR4) is expressed in a large variety of human cancers, including hematologic malignancies, and this receptor and its ligand, stromal cell-derived factor-1 (SDF-1), play a crucial role in cancer progression. We generated a humanized immunoglobulin G1 mAb, hz515H7, which binds human CXCR4, efficiently competes for SDF-1 binding, and induces a conformational change in CXCR4 homodimers. Furthermore, it inhibits both CXCR4 receptor-mediated G-protein activation and β-arrestin-2 recruitment following CXCR4 activation. The binding of the hz515H7 antibody to CXCR4 inhibits the SDF-1-induced signaling pathway, resulting in reduced phosphorylation of downstream effectors, such as Akt, Erk1/2, p38, and GSK3β. Hz515H7 also strongly inhibits cell migration and proliferation and, while preserving normal blood cells, induces both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against neoplastic cells. In mouse xenograft models, hz515H7 displays antitumor activities with multiple hematologic tumor cell lines, with its Fc-mediated effector functions proving essential in this context. Furthermore, hz515H7 binds to primary tumor cells from acute myeloid leukemia and multiple myeloma patients. Collectively, our results demonstrate two major mechanisms of action, making hz515H7 unique in this regard. Its potential as a best-in-class molecule is currently under investigation in a phase I clinical trial. Mol Cancer Ther; 15(8); 1890-9. ©2016 AACR.

The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC.

CXCR4-antagonist Peptide R-liposomes for combined therapy against lung metastasis

The chemokine CXCL12 activates CXCR4, initiating multiple pathways that control immune cell trafficking, angiogenesis and embryogenesis; CXCR4 is also overexpressed in multiple tumors affecting metastatic dissemination. While there has been great enthusiasm for exploiting the CXCR4-CXCL12 axis as a target in cancer therapy, to date the promise has yet to be fulfilled. A new class of CXCR4-antagonist cyclic peptides was recently developed and the compound named Peptide R was identified as the most active. With the intent to improve the efficacy and biodistribution of Peptide R, stealth liposomes decorated with Peptide R were developed (PL-Peptide R). In vitro PL-Peptide R efficiently inhibited CXCR4-dependent migration and in vivo it significantly reduced lung metastases and increased overall survival in B16-CXCR4 injected C57BL/6 mice. To evaluate if PL-Peptide R could also be a drug delivery system for CXCR4 expressing tumors, the PL-Peptide R was loaded with doxorubicin (DOX) (PL-Peptide R-DOX). PL-Peptide R-DOX efficiently delivered DOX to CXCR4 expressing cell lines with a consequent decrease in the DOX IC50 efficient dose. In vivo, B16-CXCR4 injected C57BL/6 mice treated with PL-Peptide R-DOX developed fewer lung metastases compared to PL-DOX treated mice. This work provides the proof-of-concept to prevent metastasis by using combined nanomedicine.

Clinical significance of enlarged lateral pelvic lymph nodes before and after preoperative chemoradiotherapy for rectal cancer

Preoperative chemoradiotherapy (CRT) with total mesorectal excision (TME) is the widely accepted treatment for rectal cancer (RC) in Western countries. However, there remains controversy as to whether preoperative CRT is useful in tumors that extend beyond the mesorectum, including metastasis to the lateral pelvic lymph nodes (LPLN). The aim of this study was to assess the prognostic significance of LPLN enlargement in patients with RC who receive preoperative CRT followed by TME without LPLN dissection. We evaluated the prognostic effect of radiographic LPLN enlargement before and after CRT, as well as the patients' clinicopathological and genetic profiles. Of the 104 patients investigated, pretreatment imaging identified 19 (18%) as LPLN-positive (>7 mm in diameter). Of these 19 patients, 7 (37%) exhibited LPLN downsizing to <7 mm following CRT. The median follow-up period was 52 months. The 5-year cancer-specific survival (CSS) or relapse-free survival (RFS) did not differ significantly between patients who did and those who did not have positive LPLN on pretreatment imaging. However, LPLN that remained positive after CRT were significantly associated with poorer 5-year CSS (73 vs. 84%, respectively; P=0.0052) and RFS (32 vs. 78%, respectively; P=0.0264). None of the patients whose LPLN were downsized to <7 mm following CRT developed recurrence; however, those with positive LPLN after CRT had a 55% higher recurrence rate, characterized by delayed local recurrence, a pattern that may be affected by certain chemokines. In conclusion, changes in initially positive LPLN (>7 mm) may predict the prognosis of patients with RC who receive preoperative CRT-TME. LPLN positivity after CRT was associated with shorter CSS and RFS. Strategies to improve patient survival may include selective LPLN dissection or more aggressive multimodality therapy.

Paracrine SDF-1α signaling mediates the effects of PSCs on GEM chemoresistance through an IL-6 autocrine loop in pancreatic cancer cells

Pancreatic cancer exhibits the poorest prognosis among all tumors and is characterized by high resistance to the currently available chemotherapeutic agents. Our previous studies have suggested that stromal components could promote the chemoresistance of pancreatic cancer cells (PCCs). Here, we explored the roles of pancreatic stellate cells (PSCs) and the SDF-1α/CXCR4 axis in pancreatic cancer chemoresitance. Our results showed that primary PSCs typically expressed SDF-1α, whereas its receptor CXCR4 was highly expressed in PCCs. PSC-conditioned medium (PSC-CM) inhibited Gemcitabine (GEM)-induced cytotoxicity and apoptosis in the human PCC line Panc-1, which was antagonized by an SDF-1α neutralizing Ab. Recombinant human SDF-1α (rhSDF-1α) increased IL-6 expression and secretion in Panc-1 cells in a time and dose-dependent manner, and this effect was suppressed by the CXCR4 antagonist AMD3100. rhSDF-1α protected Panc-1 cells from GEM-induced apoptosis, and the protective effect was significantly reduced by blocking IL-6 using a neutralizing antibody. Moreover, rhSDF-1α increased FAK, ERK1/2, AKT and P38 phosphorylation in Panc-1 cells, and either FAK or ERK1/2 inhibition suppressed SDF-1α-upregulated IL-6 expression. SDF-1α-induced AKT activation was almost completely blocked by FAK inhibition. In conclusion, we demonstrate for the first time that PSCs promote the chemoresistance of PCCs to GEM, and this effect is mediated by paracrine SDF-1α/CXCR4 signaling-induced activation of the intracellular FAK-AKT and ERK1/2 signaling pathways and a subsequent IL-6 autocrine loop in PCCs. Our findings indicate that blocking the PSC-PCC interaction by inhibiting SDF-1α/CXCR4 signaling may be a promising therapeutic strategy for overcoming chemoresistance in pancreatic cancer.

CXCR4 over-expression and survival in cancer: a system review and meta-analysis

C-X-C chemokine receptor 4 (CXCR4) is frequently over-expressed in various types of cancer; many agents against CXCR4 are in clinical development currently despite variable data for the prognostic impact of CXCR4 expression. Here eighty-five studies with a total of 11,032 subjects were included to explore the association between CXCR4 and progression-free survival (PFS) or overall survival (OS) in subjects with cancer. Pooled analysis shows that CXCR4 over-expression is significantly associated with poorer PFS (HR 2.04; 95% CI, 1.72-2.42) and OS (HR=1.94; 95% CI, 1.71-2.20) irrespective of cancer types. Subgroup analysis indicates significant association between CXCR4 and shorter PFS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, renal cancer, gynecologic cancer, pancreatic cancer and liver cancer; the prognostic effects remained consistent across age, risk of bias, levels of adjustment, median follow-up period, geographical area, detection methods, publication year and size of studies. CXCR4 over-expression predicts unfavorable OS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, head and neck cancer, renal cancer, lung cancer, gynecologic cancer, liver cancer, prostate cancer and gallbladder cancer; these effects were independence of age, levels of adjustment, publication year, detection methods and follow-up period. In conclusion, CXCR4 over-expression is associated with poor prognosis in cancer.

Chemotherapeutic agents attenuate CXCL12-mediated migration of colon cancer cells by selecting for CXCR4-negative cells and increasing peptidase CD26

Background

Recurrence of colorectal cancer (CRC) may arise due to the persistence of drug-resistant and cancer-initiating cells that survive exposure to chemotherapy. Proteins responsible for this recurrence include the chemokine receptor CXCR4, which is known to enable CRC metastasis, as well as the cancer-initiating cell marker and peptidase CD26, which terminates activity of its chemokine CXCL12.

Methods

We evaluated the expression and function of CXCR4 and CD26 in colon cancer cell lines and xenografts following treatment with common chemotherapies using radioligand binding, flow cytometry, immunofluorescence, and enzymatic assays.

Results

5-Fluorouracil, oxaliplatin and SN-38 (the active metabolite of irinotecan), as well as cisplatin, methotrexate and vinblastine, each caused decreases in cell-surface CXCR4 and concomitant increases in CD26 on HT-29, T84, HRT-18, SW480 and SW620 CRC cell lines. Flow cytometry indicated that the decline in CXCR4 was associated with a significant loss of CXCR4+/CD26- cells. Elevations in CD26 were paralleled by increases in both the intrinsic dipeptidyl peptidase activity of CD26 as well as its capacity to bind extracellular adenosine deaminase. Orthotopic HT-29 xenografts treated with standard CRC chemotherapeutics 5-fluorouracil, irinotecan, or oxaliplatin showed dramatic increases in CD26 compared to untreated tumors. Consistent with the loss of CXCR4 and gain in CD26, migratory responses to exogenous CXCL12 were eliminated in cells pretreated with cytotoxic agents, although cells retained basal motility. Analysis of cancer-initiating cell CD44 and CD133 subsets revealed drug-dependent responses of CD26/CD44/CD133 populations, suggesting that the benefits of combining standard chemotherapies 5-fluoruracil and oxaliplatin may be derived from their complementary elimination of cell populations.

Conclusion

Our results indicate that conventional anticancer agents may act to inhibit chemokine-mediated migration through eradication of CXCR4+ cells and attenuation of chemokine gradients through elevation of CD26 activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1702-2) contains supplementary material, which is available to authorized users.

CXCL10/CXCR3 overexpression as a biomarker of poor prognosis in patients with stage II colorectal cancer

The CXCL10/CXCR3 axis of inflammatory mediators is one of the most important groups of chemokine axes, which has been proven to be a lymphocyte-associated metastasis mediator in several tumors. The term inflammatory adhesions refers to tumors found to be attached to the surrouding tissues during surgery, although no cancer cell infiltration is later identified on pathological examination. The aim of the present study was to investigate the clinical characteristics of stage II colorectal cancer (CRC) and determine the correlation between the CXCL10/CXCR3 axis, inflammatory adhesions and prognosis. Clinicohistopathological data were collected from 401 CRC patients who had undergone R0 resection. Statistical analysis was performed with SPSS 17.0 software. Immunohistochemistry (IHC) was applied to measure the expression of CXCL10 and CXCR3 in 71 recurrent CRC patients, 72 non-recurrent CRC patients and 10 samples from normal peritumoral tissues, all retrieved from the Tianjin Medical University Cancer Institute and Hospital, Tianjin, China. Inflammatory adhesions, tumor location and size and the number of high-risk factors for reccurrence were more significantly associated with overall survival (OS) rather than disease-free survival in all the patients as determined by the log-rank and Cox's regression hazard analysis. Further analysis demonstrated that only the presence of inflammatory adhesions (P=0.025) was associated with the OS of recurrent patients. Patients with recurrence exhibited higher CXCR3 (P<0.001) and CXCL10 (P<0.001) expression compared with non-recurrent patients, as determined by IHC. The correlation between clinicopathological variables, CXCL10/CXCR3 expression and survival was also analyzed: Inflammatory adhesions and general tumor type (ulcerated vs. elevated) exhibited a significant correlation with CXCR3; however, the expression of CXCL10 was not significantly correlated with tumor location, histological type, size, gender, or preoperative carcinoembryonic antigen and hemoglobin levels. Furthermore, patients exhibiting a high expression of CXCR3 presented with a higher risk of relapse; among those, patients with inflammatory adhesions always exhibited worse survival. However, no such association was identified for CXCL10 expression. In conclusion, CXCR3 expression may be used as a prognostic marker and may contribute to the prediction of clinical outcome in stage II CRC patients.

Increase in apoptosis by combination of metformin with silibinin in human colorectal cancer cells

AIM: To investigate the effect of metformin on silibinin-induced apoptosis in human colorectal cancer (COLO 205) cells.

METHODS: MTT assays were performed to quantify cell viability. Western blot assays were applied to identify the expression of signaling proteins.

RESULTS: The combined treatment of COLO 205 cells with metformin and silibinin decreased cell survival at a dose insufficient to influence the non-malignant cells [Human colonic epithelial cells (HCoEpiC)]. Silibinin and metformin increased phosphatase and tensin homolog and 5’-adenosine monophosphate-activated protein kinase expression in COLO 205 cells and inhibited the phosphorylation of mammol/Lalian target of rapamycin. This combined treatment resulted in an increase in the expression of activated caspase 3 and apoptosis inducing factor, indicating apoptosis.

CONCLUSION: The combined treatment of human colorectal cancer cells with silibinin and metformin may induce apoptosis at a dose that does not affect HCoEpiC. This finding reveals a potential therapeutic strategy for the treatment of colorectal cancer.

Disclosing the CXCR4 expression in lymphoproliferative diseases by targeted molecular imaging

Chemokine ligand-receptor interactions play a pivotal role in cell attraction and cellular trafficking, both in normal tissue homeostasis and in disease. In cancer, chemokine receptor-4 (CXCR4) expression is an adverse prognostic factor. Early clinical studies suggest that targeting CXCR4 with suitable high-affinity antagonists might be a novel means for therapy. In addition to the preclinical evaluation of [(68)Ga]Pentixafor in mice bearing human lymphoma xenografts as an exemplary CXCR4-expressing tumor entity, we report on the first clinical applications of [(68)Ga]Pentixafor-Positron Emission Tomography as a powerful method for CXCR4 imaging in cancer patients. [(68)Ga]Pentixafor binds with high affinity and selectivity to human CXCR4 and exhibits a favorable dosimetry. [(68)Ga]Pentixafor-PET provides images with excellent specificity and contrast. This non-invasive imaging technology for quantitative assessment of CXCR4 expression allows to further elucidate the role of CXCR4/CXCL12 ligand interaction in the pathogenesis and treatment of cancer, cardiovascular diseases and autoimmune and inflammatory disorders.

Downregulation of the CXCR4/CXCL12 axis blocks the activation of the Wnt/β-catenin pathway in human colon cancer cells

Chemokine CXCL12 is an extracellular chemokine, which binds to its cell surface receptor CXCR4. High expressions of CXCR4 and CXCL12 are associated with biological malignant potential in colon cancers. We aimed to investigate the roles of the CXCR4/CXCL12 axis in activation of the Wnt/β-catenin pathway in the development of colon cancers. Using colon cancer cell line, we performed the RNA interference assay to downregulate the expression of CXCR4. Cells were exposed to CXCL12 and their growth and metastatic activity were examined. Matrix metalloproteinases (MMPs) activity were analyzed by the gelatin zymography assay. Cell migration ability was estimated by assays of scratch wound and transwell chamber. The expression of CXCR4 and molecules relevant to the Wnt/β-catenin pathway were analyzed by the western blotting and real-time PCR assays. Human colon cancer HT-29 cells identified high expression of CXCR4. HT-29 cells highly responded to CXCL12 stimulation, showing the increase of cell proliferation, invasion and migration through the Matrigeal. The secretion and activity of MMP-2 and MMP-9 were also stimulated in HT-29 cells exposure to CXCL12. However, the CXCR4 knockdown HT-29 cells did not response to CXCL12 stimulation. We suggested that the activation of the CXCR4/CXCL12 axis be blocked in the CXCR4 knockdown cells. This study indicated that one key to the role of the CXCR4/CXCL12 axis is activation of the Wnt/β-catenin pathway. Downregulation of the CXCR4/CXCL12 axis thus reduces cancer growth and metastasis. Targeted therapy utilizing the CXCR4/CXCL12 axis could be an effective strategy for treatment of colon cancers.

CXCR4 expression enhances diffuse large B cell lymphoma dissemination and decreases patient survival

The chemokine receptor CXCR4 has been implicated in the migration and trafficking of malignant B cells in several haematological malignancies. Over-expression of CXCR4 has been identified in haematological tumours, but data concerning the role of this receptor in diffuse large B cell lymphoma (DLBCL) are lacking. CXCR4 is a marker of poor prognosis in various neoplasms, correlating with metastatic disease and decreased survival of patients. We studied CXCR4 involvement in cell migration in vitro and dissemination in vivo. We also evaluated the prognostic significance of CXCR4 in 94 biopsies of DLBCL patients. We observed that the level of expression of CXCR4 in DLBCL cell lines correlated positively with in vitro migration. Expression of the receptor was also associated with increased engraftment and dissemination, and decreased survival time in NOD/SCID mice. Furthermore, administration of a specific CXCR4 antagonist, AMD3100, decreased dissemination of DLBCL cells in a xenograft mouse model. In addition, we found that CXCR4 expression is an independent prognostic factor for shorter overall survival and progression-free survival in DLBCL patients. These results show that CXCR4 mediates dissemination of DLBCL cells and define for the first time its value as an independent prognostic marker in DLBCL patients.