Systemic Delivery of an Adjuvant CXCR4-CXCL12 Signaling Inhibitor Encapsulated in Synthetic Protein Nanoparticles for Glioma Immunotherapy

Glioblastoma (GBM) is an aggressive primary brain cancer, with a 5 year survival of ∼5%. Challenges that hamper GBM therapeutic efficacy include (i) tumor heterogeneity, (ii) treatment resistance, (iii) immunosuppressive tumor microenvironment (TME), and (iv) the blood-brain barrier (BBB). The C-X-C motif chemokine ligand-12/C-X-C motif chemokine receptor-4 (CXCL12/CXCR4) signaling pathway is activated in GBM and is associated with tumor progression. Although the CXCR4 antagonist (AMD3100) has been proposed as an attractive anti-GBM therapeutic target, it has poor pharmacokinetic properties, and unfavorable bioavailability has hampered its clinical implementation. Thus, we developed synthetic protein nanoparticles (SPNPs) coated with the transcytotic peptide iRGD (AMD3100-SPNPs) to target the CXCL2/CXCR4 pathway in GBM via systemic delivery. We showed that AMD3100-SPNPs block CXCL12/CXCR4 signaling in three mouse and human GBM cell cultures in vitro and in a GBM mouse model in vivo. This results in (i) inhibition of GBM proliferation, (ii) reduced infiltration of CXCR4⁺ monocytic myeloid-derived suppressor cells (M-MDSCs) into the TME, (iii) restoration of BBB integrity, and (iv) induction of immunogenic cell death (ICD), sensitizing the tumor to radiotherapy and leading to anti-GBM immunity. Additionally, we showed that combining AMD3100-SPNPs with radiation led to long-term survival, with ∼60% of GBM tumor-bearing mice remaining tumor free after rechallenging with a second GBM in the contralateral hemisphere. This was due to a sustained anti-GBM immunological memory response that prevented tumor recurrence without additional treatment. In view of the potent ICD induction and reprogrammed tumor microenvironment, this SPNP-mediated strategy has a significant clinical translation applicability.

CXCL12/CXCR4 axis gene variants contribute to an increased vulnerability to HPV infection and cervical oncogenesis

PURPOSE

Every year, more than half a million women are diagnosed with cervical cancer (CC). Individual factors may contribute to the cervical cancer development, such as immunogenetic variation. CXCL12/CXCR4 axis is involved in tumor progression and aggressiveness. In the present study, we aimed to investigate a possible association between two single-nucleotide variants (CXCL12 rs1801157 and CXCR4 rs2228014) with HPV infection and cervical cancer development.

METHODS

PCR technique was used to test HPV positivity in 424 women, in which the allelic frequency of CXCL12 rs1801157 and CXCR4 rs2228014 was also assessed by PCR-restriction fragment length polymorphism.

RESULTS

CXCL12 rs1801157 was associated with HPV infection in the allelic distribution as well in the codominant, dominant and recessive genetic models; as well with squamous intraepithelial lesions (SIL) and CC in the codominant and dominant models. CXCR4 rs2228014 was associated to HPV infection in the codominant model and allelic distribution; as well with SIL/CC in the codominant, dominant and allelic models. Independent associations were found for CXCL12 AA genotype and HPV infection, SIL and CC development, as well as, CXCR4 allele T and HPV infection and CC. The variants interaction analysis demonstrated that the presence of both polymorphisms increases the susceptibility of HPV infection in 10.1 times, SIL (2 times) and CC development in 4.2 times.

CONCLUSIONS

This is the first study demonstrating that the interaction of CXCL12 and CXCR4 variants contributes to the increased susceptibility of HPV infection, squamous intraepithelial lesions and cervical cancer development.

Potential Role of CXCR4 Targeting in the Context of Radiotherapy and Immunotherapy of Cancer

Cancer immunotherapy has been established as standard of care in different tumor entities. After the first reports on synergistic effects with radiotherapy and the induction of abscopal effects-tumor shrinkage outside the irradiated volume attributed to immunological effects of radiotherapy-several treatment combinations have been evaluated. Different immunotherapy strategies (e.g., immune checkpoint inhibition, vaccination, cytokine based therapies) have been combined with local tumor irradiation in preclinical models. Clinical trials are ongoing in different cancer entities with a broad range of immunotherapeutics and radiation schedules. SDF-1 (CXCL12)/CXCR4 signaling has been described to play a major role in tumor biology, especially in hypoxia adaptation, metastasis and migration. Local tumor irradiation is a known inducer of SDF-1 expression and release. CXCR4 also plays a major role in immunological processes. CXCR4 antagonists have been approved for the use of hematopoietic stem cell mobilization from the bone marrow. In addition, several groups reported an influence of the SDF-1/CXCR4 axis on intratumoral immune cell subsets and anti-tumor immune response. The aim of this review is to merge the knowledge on the role of SDF-1/CXCR4 in tumor biology, radiotherapy and immunotherapy of cancer and in combinatorial approaches.

The CXCL12 rs1801157 polymorphism and risk of colorectal cancer: a meta-analysis

Background

The CXCL12 rs1801157 polymorphism is putatively associated with the risk of malignancy. However, research results are inconsistent regarding particular cancers, especially colorectal cancer (CRC).

Methods

We conducted a meta-analysis via a comprehensive literature search of the databases PubMed and Embase. Odds ratios and their corresponding 95% confidence intervals were extracted to assess comprehensively the association between the CXCL12 rs1801157 polymorphism and the risk of CRC.

Results

According to the following models, the correlation between the presence of the CXCL12 rs1801157 polymorphism and the risk of CRC was not statistically significant: allelic (G cf. A), heterozygous (GG cf. GA), homozygous (GG cf. AA), dominant (GG cf. GA+AA), or recessive (AA cf. GA+GG) for pooled calculating. However, in subgroup analysis, elevated risk of CRC was found in the non-Caucasian group in four genetic models, while no connection was found in the Caucasian group. The sensitivity analysis confirmed that the result of the Caucasian group was stable and analyzed the heterogeneity of the non-Caucasian group.

Conclusion

This meta-analysis suggested that the CXCL12 rs1801157 polymorphism did not significantly confer a risk of CRC among Caucasians but may among non-Caucasians. These results warrant confirmation and further studies of different ethnic populations.

Association of rs1801157 single nucleotide polymorphism of CXCL12 gene in breast cancer in Pakistan and in-silico expression analysis of CXCL12-CXCR4 associated biological regulatory network

Background

C-X-C chemokine ligand 12 (CXCL12) has important implications in breast cancer (BC) pathogenesis. It is selectively expressed on B and T lymphocytes and is involved in hematopoiesis, thymocyte trafficking, stem cell motility, neovascularization, and tumorigenesis. The single nucleotide polymorphism (SNP) rs1801157 of CXCL12 gene has been found to be associated with higher risk of BC.

Methods

Our study focuses on the genotypic and allelic distribution of SNP (rs1801157; G/A) in Pakistani population as well as its association with the clinico-pathological features. The association between rs1801157 genotypes (G/A) and BC risks was assessed by a multivariate logistic regression (MLR) analysis. Genotyping was performed in both healthy individuals and patients of BC using PCR-restriction fragment length polymorphism (PCR-RFLP) method. Furthermore, in-silico approaches were adapted to investigate the association of CXCL12 and its receptor CXCR4 with genes/proteins involved in BC signalling.

Results

Significant differences in allelic and genotypic distribution between BC patients and healthy individuals of genotype (G/G) and (A/G) (p < 0.05) were observed. The frequency of the allele G in the BC group (77%) was significantly higher as compared to control group (61%) (p = 0.01). The association of genotype GG with clinico-pathological features including age, stages of cancer and organ (lung, liver, bones and brain) metastasis (p > 0.05) was assessed. In a MLR analysis, a number of variables including age, weight of an individual, affected lymph nodes, hormonal status (estrogen and progesterone receptor), alcohol consumption and family history associated with the GG genotype (GG:AA, odds ratio (OR) = 1.30, 95% CI [1.06–1.60]) were found to be independent risk factors for BC. Our in-vitro results suggest that genotype GG is possibly increasing the risk of BC in Pakistani cohorts. in-silico analysis finds that CXCL12–CXCR4 is associated with an increased expression of PDZK1, PI3k and Akt which lead the breast tumor towards metastasis.

Conclusion

Multiple targets such as CXCL12, CXCR4, PDZK1, PI3k and Akt can be inhibited in combined strategies to treat BC metastasis.

Single Nucleotide Polymorphisms in Genes MACC1, RAD18, MMP7 and SDF-1a As Prognostic Factors in Resectable Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) represents one of the most common malignancies worldwide. Research has indicated that functional gene changes such as single nucleotide polymorphism (SNP) influence carcinogenesis and metastasis and might have an influence on disease relapse. The aim of our study was to evaluate the role of SNPs in selected genes as prognostic markers in resectable CRC.

PATIENTS AND METHODS

In total, 163 consecutive patients treated surgically for CRC of stages I, II and III at the University Medical Centre in Maribor in 2007 and 2008 were investigated. DNA was isolated from formalin-fixed paraffin-embedded CRC tissue from the Department of Pathology and SNPs in genes SDF-1a, MMP7, RAD18 and MACC1 were genotyped using polymerase chain reaction followed by high resolution melting curve analysis or restriction fragment length polymorphism.

RESULTS

We found worse disease-free survival (DFS) for patients with TT genotype of SNP rs1990172 in gene MACC1 (p = 0.029). Next, we found worse DFS for patients with GG genotype for SNP rs373572 in gene RAD18 (p = 0.020). Higher frequency of genotype GG of MMP7 SNP rs11568818 was found in patients with T3/T4 stage (p = 0.014), N1/N2 stage (p = 0.041) and with lymphovascular invasion (p = 0.018). For MACC1 rs1990172 SNP we found higher frequency of genotype TT in patients with T3/T4 staging (p = 0.024). Higher frequency of genotype GG of RAD18 rs373572 was also found in patients with T1/T2 stage with disease relapse (p = 0.041).

CONCLUSIONS

Our results indicate the role of SNPs as prognostic factors in resectable CRC.

Cytokine Regulation of Metastasis and Tumorigenicity

The human body combats infection and promotes wound healing through the remarkable process of inflammation. Inflammation is characterized by the recruitment of stromal cell activity including recruitment of immune cells and induction of angiogenesis. These cellular processes are regulated by a class of soluble molecules called cytokines. Based on function, cell target, and structure, cytokines are subdivided into several classes including: interleukins, chemokines, and lymphokines. While cytokines regulate normal physiological processes, chronic deregulation of cytokine expression and activity contributes to cancer in many ways. Gene polymorphisms of all types of cytokines are associated with risk of disease development. Deregulation RNA and protein expression of interleukins, chemokines, and lymphokines have been detected in many solid tumors and hematopoetic malignancies, correlating with poor patient prognosis. The current body of literature suggests that in some tumor types, interleukins and chemokines work against the human body by signaling to cancer cells and remodeling the local microenvironment to support the growth, survival, and invasion of primary tumors and enhance metastatic colonization. Some lymphokines are downregulated to suppress tumor progression by enhancing cytotoxic T cell activity and inhibiting tumor cell survival. In this review, we will describe the structure/function of several cytokine families and review our current understanding on the roles and mechanisms of cytokines in tumor progression. In addition, we will also discuss strategies for exploiting the expression and activity of cytokines in therapeutic intervention.

Analysis of the expression of SDF-1 splicing variants in human colorectal cancer and normal mucosa tissues

C-X-C motif chemokine ligand 12 (CXCL12), also termed stromal cell-derived factor-1 (SDF-1) is a small protein 8-14 kDa in length that is expressed as six isoforms, consisting of SDF-1α, SDF-1β, SDF-1γ, SDF-1δ, SDF-1ε and SDF-1θ. All six isoforms are encoded by the single CXCL12 gene on chromosome 10. This gene regulates leukocyte trafficking and is variably expressed in a number of normal and cancer tissues. The potential role of the novel CXCL12 splice variants as components of the CXCR4 axis in cancer development is not fully understood. The present study aimed to analyze the expression profile of the various SDF-1 isoforms and SDF-1 polymorphisms, and the association with the clinicopathological features and overall survival of patients with colorectal cancer (CRC). SDF-1 polymorphism analysis was performed using restriction fragment length polymorphism (RFLP) analysis in 73 histologically confirmed human CRC tissue samples at various stages of disease. The expression pattern of the SDF-1 isoforms was analyzed by reverse transcription-polymerase chain reaction in 40 histologically confirmed human CRC tissue samples obtained at various stages of disease, as well as in matched adjacent normal mucosa samples. The presence of the CXCL12 gene polymorphism rs1801157 demonstrated an association with local progression of the primary tumor, as indicated by the T stage. The frequency of the GG genotype was slightly increased in patients with stage 3 and 4 tumors (78.0%) compared with the incidence of the GA/AA genotype (69.5%; P=0.067). The expression of SDF-1β was associated with the presence of metastases (P=0.0656) and the expression of SDF-1γ was significantly associated with tumor size (P=0.0423). The present study is the first to analyze the association between the expression profile of the chemokine CXCL12 splice variants in human CRC tissues and their clinical relevance. The present results reveal that the CXCL12 G801A polymorphism is a low-penetrance risk factor for the development of CRC, and was associated with the T stage. All six isoforms of SDF-1 were expressed in CRC tissues. The expression of SDF-1β was found to be associated with metastases and SDF-1γ appears to be a possible tumor marker for local tumor progression.

Single Nucleotide Polymorphisms as Prognostic and Predictive Factors of Adjuvant Chemotherapy in Colorectal Cancer of Stages I and II

Colorectal cancer (CRC) is a highly heterogeneous disease regarding the stage at time of diagnosis and there is special attention regarding adjuvant chemotherapy in unselected patients with stage I and stage II. The clinicohistologically based TNM staging system with emphasis on histological evaluation of primary tumor and resected regional lymph nodes remains the standard of staging, but it has restricted sensitivity resulting in false downward stage migration. Molecular characteristics might predispose tumors to a worse prognosis and identification of those enables identifying patients with high risk of disease recurrence. Suitable predictive markers also enable choosing the most appropriate therapy. The current challenge facing adjuvant chemotherapy in stages I and II CRC is choosing patients with the highest risk of disease recurrence who are going to derive most benefit without facing unnecessary adverse effects. Single nucleotide polymorphisms (SNPs) are one of the potential molecular markers that might help us identify patients with unfavorable prognostic factors regarding disease initiation and recurrence and could determine selection of an appropriate chemotherapy regimen in the adjuvant and metastatic setting. In this paper, we discuss SNPs of genes involved in the multistep processes of cancerogenesis, metastasis, and the metabolism of chemotherapy that might prove clinically significant.

Targeting Stromal-Cancer Cell Crosstalk Networks in Ovarian Cancer Treatment

Ovarian cancer is a histologically, clinically, and molecularly diverse disease with a five-year survival rate of less than 30%. It has been estimated that approximately 21,980 new cases of epithelial ovarian cancer will be diagnosed and 14,270 deaths will occur in the United States in 2015, making it the most lethal gynecologic malignancy. Ovarian tumor tissue is composed of cancer cells and a collection of different stromal cells. There is increasing evidence that demonstrates that stromal involvement is important in ovarian cancer pathogenesis. Therefore, stroma-specific signaling pathways, stroma-derived factors, and genetic changes in the tumor stroma present unique opportunities for improving the diagnosis and treatment of ovarian cancer. Cancer-associated fibroblasts (CAFs) are one of the major components of the tumor stroma that have demonstrated supportive roles in tumor progression. In this review, we highlight various types of signaling crosstalk between ovarian cancer cells and stromal cells, particularly with CAFs. In addition to evaluating the importance of signaling crosstalk in ovarian cancer progression, we discuss approaches that can be used to target tumor-promoting signaling crosstalk and how these approaches can be translated into potential ovarian cancer treatment.

CXCL12 genetic variants as prognostic markers in nasopharyngeal carcinoma

The chemokine receptor 4/chemokine ligand 12 (CXCR4/CXCL12) axis plays an important role in tumorigenesis, metastasis, and recurrence of tumors. Its single nucleotide polymorphisms (SNPs) are associated with patient survival in several types of cancer. However, the prognostic value of SNPs in nasopharyngeal carcinoma (NPC) has not been fully investigated. This retrospective study assessed the relationships between CXCR4 rs2228014 and CXCL12 rs1801157 polymorphisms and patient outcome in 222 patients newly diagnosed with NPC. The analysis found no significant correlation between the presence of both SNPs and clinicopathological factors. However, univariate analysis showed that N classification, clinical stage, and the CXCL12 rs1801157 polymorphism were significantly associated with distant metastasis-free survival (P=0.018, 0.028, and 0.013, respectively) and progression-free survival (P=0.007, 0.046, and 0.021, respectively). After adjusting clinicopathological factors, multivariate analysis identified CXCL12 rs1801157 as an independent prognostic factor for distant metastasis-free survival and progression-free survival (hazard ratio: 3.332; 95% confidence interval: 1.597-6.949; P=0.001 and hazard ratio: 2.665 95% confidence interval: 1.387-5.119; P=0.003, respectively). Our results suggest that CXCL12 rs1801157 AA genotype might serve as a potential prognostic factor in patients with NPC.

Relationship between SDF-1G801A polymorphism and its expression in Tunisian patients with colorectal cancer

The aim was to evaluate the relationship between SDF-1G801A polymorphism and its immunohistochemical expression in colorectal cancer tissues in the Tunisian cohort. The molecular and immunohistochemical analysis showed that SDF-1G801A polymorphic variant was higher in CRC patients with TNM stage II and III, the SDF-1 expression was significantly increased from normal mucosa to primary tumor (p < 0.05). CRC patients have higher frequency of A allele (52.01%) than controls (26.8%) (P = 0.0001). Thus, SDF-1 polymorphism is a risk factor of colorectal cancer susceptibility in our population, the polymorph genotype of SDF-1 maybe associated with clinical manifestations in CRC patients in Tunisia.

Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis

Ovarian cancer is the most lethal gynecological malignancy. It is usually diagnosed at a late stage, with a 5-yr survival rate of <30%. The majority of ovarian cancer cases are diagnosed after tumors have widely spread within the peritoneal cavity, limiting the effectiveness of debulking surgery and chemotherapy. Owing to a substantially lower survival rate at late stages of disease than at earlier stages, the major cause of ovarian cancer deaths is believed to be therapy-resistant metastasis. Although metastasis plays a crucial role in promoting ovarian tumor progression and decreasing patient survival rates, the underlying mechanisms of ovarian cancer spread have yet to be thoroughly explored. For many years, researchers have believed that ovarian cancer metastasizes via a passive mechanism by which ovarian cancer cells are shed from the primary tumor and carried by the physiological movement of peritoneal fluid to the peritoneum and omentum. However, the recent discovery of hematogenous metastasis of ovarian cancer to the omentum via circulating tumor cells instigated rethinking of the mode of ovarian cancer metastasis and the importance of the "seed-and-soil" hypothesis for ovarian cancer metastasis. In this review we discuss the possible mechanisms by which ovarian cancer cells metastasize from the primary tumor to the omentum, the cross-talk signaling events between ovarian cancer cells and various stromal cells that play crucial roles in ovarian cancer metastasis, and the possible clinical implications of these findings in the management of this deadly, highly metastatic disease.

Neurokinin-2 receptor polymorphism predicts lymph node metastasis in colorectal cancer patients

To analyze the single nucleotide polymorphisms (SNPs) of two subtypes of neurokinin (NK) receptors, NK1R and NK2R (also known as TAC1R and TAC2R), in colorectal cancer (CRC), peripheral blood samples were collected from 199 CRC patients. Direct-sequencing was performed to identify the NK1R rs10198644 and NK2R rs4644560 SNPs. Genotype results were correlated with clinical factors. The allele frequencies of NK1R rs10198644 GC, CC and GG were 52, 17 and 31%, respectively, while that of NK2R rs4644560 GC, CC, and GG were 36, 50 and 14%, respectively. Patients with NK2R rs4644560 GC exhibited more positive lymph nodes than those with CC (mean, 2.2 vs. 1.3; P=0.016). Further analysis highlighted that the number of positive lymph nodes was also increased in the NK2R rs4644560 GC/NK1R rs10198644 GG group compared with the NK2R rs4644560 GG/NK1R rs10198644 GG group (mean, 2.2 vs. 0.9; P=0.04). These data suggested that the NK2R rs4644560 GC polymorphism alone or combination with NK1R rs10198644 GG may be a promising prognostic marker of lymph node metastasis in CRC patients.

Stromal cell-derived factor-1 G801A polymorphism and the risk factors for cervical cancer

Although certain studies have demonstrated no association between the stromal cell‑derived factor‑1 (SDF1‑3') G801A single nucleotide polymorphism (SNP) and cervical carcinoma, the interactions between the SDF1‑3' G801A SNP and contraceptive use, menopausal status, parity and tobacco smoking remain to be fully elucidated. Using polymerase chain reaction‑restriction fragment length polymorphism, the distribution of SDF1‑3' G801A genotypes in patients with cervical cancer (n=462) against control groups (n=497) was investigated. Logistic regression analysis, adjusting for age, pregnancy, oral contraceptive use, tobacco smoking and menopausal status, did not identify the SDF1‑3' G801A polymorphism as a genetic risk factor for cervical cancer. The adjusted odds ratio (OR) for patients with the A/G, vs. G/G genotype was 1.203, with a 95% confidence interval (CI) of 0.909‑1.591 (P=0.196). The adjusted OR for the A/A, vs. G/G genotype was 1.296 (95% CI=0.930‑1.807; P=0.125) and for the A/A or A/G, vs. G/G genotype was 1.262 (95% CI=0.964‑1.653; P=0.090)]. The P‑value of the χ2 test of the trend observed for the SDF1‑3' G801A polymorphism was at the borderline of being statistically significant (ptrend=0.0484). Stratified analyses between the distribution of the SDF1‑3' G801A genotypes and cervical cancer risks demonstrated that this polymorphism may be a risk factor for patients with a positive history of tobacco smoking (1.778; 95% CI=1.078‑2.934; P=0.0235). These findings suggested that the SDF1‑3' G801A polymorphism may be a genetic risk factor for cervical cancer in patients with a positive history of tobacco smoking.

Examining the polymorphisms in the hypoxia pathway genes in relation to outcome in colorectal cancer

Introduction

Colorectal cancer is a common malignancy. Identification of genetic prognostic markers may help prognostic estimations in colorectal cancer. Genes that regulate response to hypoxia and other genes that are regulated under the hypoxic conditions have been shown to play roles in cancer progression. In this study, we hypothesized that genetic variations in the hypoxia pathway genes were associated with the risk of outcome in colorectal cancer patients.

Methods

This study was performed in two phases. In the first phase, 49 SNPs from six hypoxia pathway genes (HIF1A, HIF1B, HIF2A, LOX, MIF and CXCL12) in 272 colorectal cancer patients were analyzed. In the second phase, 77 SNPs from seven hypoxia pathway genes (HIF1A, HIF1B, HIF2A, HIF2B, HIF3A, LOX and CXCL12) were analyzed in an additional cohort of 535 patients. Kaplan Meier, Cox univariate and multivariable regression analyses were performed to analyze the relationship between the SNPs and overall survival (OS), disease free survival (DFS) or disease specific survival (DSS). Since this was a hypothesis-generating study, no correction for multiple testing was applied.

Results

In phase I, one SNP (HIF2A rs11125070) was found to be associated with DFS in multivariable analysis; yet association of a proxy polymorphism (HIF2A rs4953342) was not detected in the phase II patient cohort. In phase II, associations of two SNPs (HIF2A rs4953352 and HIF2B rs12593988) were significant in both OS and DFS multivariable analyses. However, association of HIF2A rs4953352 was not replicated in the phase I cohort using a proxy SNP (HIF2A rs6706003).

Conclusion

Overall, our study did not find a convincing evidence of association of the investigated polymorphisms with the disease outcomes in colorectal cancer.

The role of chemoattractant receptors in shaping the tumor microenvironment

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.

Molecular mechanism underlying lymphatic metastasis in pancreatic cancer

As the most challenging human malignancies, pancreatic cancer is characterized by its insidious symptoms, low rate of surgical resection, high risk of local invasion, metastasis and recurrence, and overall dismal prognosis. Lymphatic metastasis, above all, is recognized as an early adverse event in progression of pancreatic cancer and has been described to be an independent poor prognostic factor. It should be noted that the occurrence of lymphatic metastasis is not a casual or stochastic but an ineluctable and designed event. Increasing evidences suggest that metastasis-initiating cells (MICs) and the microenvironments may act as a double-reed style in this crime. However, the exact mechanisms on how they function synergistically for this dismal clinical course remain largely elusive. Therefore, a better understanding of its molecular and cellular mechanisms involved in pancreatic lymphatic metastasis is urgently required. In this review, we will summarize the latest advances on lymphatic metastasis in pancreatic cancer.

CXCL12-G801A polymorphism modulates risk of colorectal cancer in Taiwan

INTRODUCTION

The chemokine CXCL12, designated stromal cell-derived factor-1 (SDF-1), plays a significant role in many cancer metastases. Previous studies have shown that CXCL12-G801A, a single nucleotide polymorphism (SNP) in the 3' untranslated region, correlates with breast and lung cancer in Iran. The aim of this study was to evaluate the association of the gene variant CXCL12-G801A with colorectal cancer (CRC) in a Taiwanese cohort.

MATERIAL AND METHODS

In this study, we used a denaturing high performance liquid chromatography (DHPLC) method to analyze the frequencies of CXCL12-G801A polymorphic variants between CRC patients (n = 258) and healthy controls (n = 300) in Taiwan.

RESULTS

The SNP distribution was higher in CRC patients with TNM stage II (117/258) than healthy controls (52/300). We observed a significant increase in the G/A plus A/A genotype of the CXCL12-G801A polymorphism in CRC patients (45.35%) compared with healthy controls (17.33%). The analysis of allelic frequencies in both groups revealed that CRC patients have a higher frequency of A allele (23.45%) than healthy controls (8.67%). Furthermore, among older CRC patients, the frequency of the CXCL12-G801A genotype was significantly increased (p = 0.0148).

CONCLUSIONS

Our observations suggest that the CXCL12-G801A genotype may be associated with some clinical manifestations in CRC patients in Taiwan.

The role of CXCR3 and CXCR4 in colorectal cancer metastasis

Chemokines and their receptors play key roles in leukocyte trafficking and are also implicated in cancer metastasis. We previously demonstrated that forced expression of CXCR3 promotes colon cancer metastasis preferentially to the draining lymph nodes (LNs), with poor prognosis. Using clinical colorectal cancer (CRC) samples, here, we show that expressions of CXCR3 and CXCR4 are significantly higher in metastatic foci within LNs and liver compared to primary tumors, whereas ligands for CXCR3 and CXCR4 are not. We also have demonstrated that some human CRC cell lines constitutively express both CXCR3 and CXCR4, and that activation of CXCR3 strengthens the CXCR4-mediated cell migration in vitro in a synergistic manner. By constructing SW620 cell lines with reduced expression of CXCR3 and/or CXCR4 using microRNA, we investigated in vivo metastatic activities in a mouse rectal transplantation model. Six weeks after inoculation, CXCR3-, CXCR4-, and CXCR3/CXCR4 double-knockdowns significantly reduced metastasis to LNs, liver and lungs, compared to the control (p < 0.05). Importantly, its suppressive effect on LN metastasis was significantly stronger in CXCR3- and CXCR3/CXCR4 double-knockdowns. In addition, CXCR3- and CXCR3/CXCR4 double-knockdowns significantly decreased the dissemination of cancer cells to liver and lungs, even after 2 weeks. These results indicate that targeting CXCR3 and CXCR4 can be a promising therapy against CRC metastasis.

SDF-1alpha G801A polymorphism in Southern Iranian patients with colorectal and gastric cancers

BACKGROUND

A single nucleotide polymorphism (SNP) in the stromal cell-derived factor-1 (SDF-1) gene at position 801 (G>A) is associated with susceptibility to certain tumors. This study aimed to investigate an association between this SNP and colorectal and gastric cancers in an Iranian population.

METHOD

Genotype and allele frequencies of SDF-1 801 G>A were assessed using polymerase chain reaction-restriction fragment length polymorphism in 109 patients with colorectal cancer, 124 with gastric cancer, and 262 normal control volunteers.

RESULTS

No statistically significant difference was observed in the frequencies of genotypes and alleles between patients and controls (p > 0.05).

CONCLUSION

SDF-1 gene polymorphism at position 801 (G>A) was not associated with colorectal and gastric cancers in Southern Iranian patients.

Integrins and their extracellular matrix ligands in lymphangiogenesis and lymph node metastasis

In the 1970s, the late Judah Folkman postulated that tumors grow proportionately to their blood supply and that tumor angiogenesis removed this limitation promoting growth and metastasis. Work over the past 40 years, varying from molecular examination to clinical trials, verified this hypothesis and identified a host of therapeutic targets to limit tumor angiogenesis, including the integrin family of extracellular matrix receptors. However, the propensity for some tumors to spread through lymphatics suggests that lymphangiogenesis plays a similarly important role. Lymphangiogenesis inhibitors reduce lymph node metastasis, the leading indicator of poor prognosis, whereas inducing lymphangiogenesis promotes lymph node metastasis even in cancers not prone to lymphatic dissemination. Recent works highlight a role for integrins in lymphangiogenesis and suggest that integrin inhibitors may serve as therapeutic targets to limit lymphangiogenesis and lymph node metastasis. This review discusses the current literature on integrin-matrix interactions in lymphatic vessel development and lymphangiogenesis and highlights our current knowledge on how specific integrins regulate tumor lymphangiogenesis.

Association of chemokine CXCL12-3'G801A polymorphism with systemic lupus erythematosus in a Han Chinese population

CXCL12, also known as stromal cell-derived factor (SDF-1), is a CXC chemokine. Recent reports have shown that CXCL12 might play key roles in a murine model of lupus and in patients with systemic lupus erythematosus (SLE). A common variant at position 801 in 3'-untranslated region in CXCL12 gene (designated CXCL12-3'G801A) has been reported in association with autoimmune diseases, such as type 1 diabetes and systemic sclerosis. We investigated the influence of CXCL12-3'G801A polymorphism on susceptibility to SLE by genotyping this single nucleotide polymorphism in 422 SLE patients and 374 healthy controls. The frequency of G/G homozygote was observed in 60.0% of SLE patients and in 52.7% of healthy individuals (χ(2 )= 4.275, p = 0.039). Compared with patients with G/A and A/A genotype, SLE patients with G/G genotype were also more prone to developing photosensitivity (χ(2 )= 6.778, p = 0.034), renal damage (χ(2 )= 6.388, p = 0.041) and to producing antibodies against nucleosomes (χ(2 )= 8.341, p = 0.015). Moreover, the plasma level of CXCL12α was also significantly increased in patients with G/G homozygote than in healthy controls carrying the same genotype [(4067.0 ± 1092.3) pg/ml vs. (3278.5 ± 547.4) pg/ml, p = 0.002]. Our results suggest that polymorphism in CXCL12-3'G801A might be a genetic risk factor for developing SLE. The association of G/G homozygote with nephritis and skin damage developed in SLE patients might be due to its effects upon the production of auto-antibodies and CXCL12 protein.

CXCL12 G801A polymorphism is associated with an increased risk of benign salivary gland tumors in the Chinese population

The chemokine CXCL12 and its receptor CXCR4 have been found to be important in tumor progression. A single-nucleotide polymorphism of CXCL12 G801A has been described and investigated in human immunodeficiency virus-1 (HIV-1) infection and in the susceptibility to several cancers. Here, we investigated the association between the CXCL12 G801A polymorphism and susceptibility to benign and malignant salivary gland tumors (SGTs) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 102 Chinese SGT patients and 101 healthy controls. The frequencies of the AG (P = 0.001; odds ratio (OR), 3.764) and AA (P = 0.004; OR, 6.852) genotypes of CXCL12 were significantly higher in patients with benign SGTs than in the healthy controls. The frequency of the A allele of CXCL12 was also significantly higher in benign SGTs (P = 0.00; OR, 1.395) compared with the healthy controls. However, the AG (P = 0.171; OR, 3.163) and AA (P = 0.854; OR, 0.667) genotypes did not increase the risk of malignant SGTs significantly. The frequency of the CXCL12 A allele was also not found to be higher in malignant SGTs (P = 0.267; OR, 1.917) compared with the controls. Taken together, our results suggested that the CXCL12 G801A polymorphism is associated with an increased risk of benign SGTs, but not malignant SGTs, in the Chinese population.

Genetic predisposition of donors affects the allograft outcome in kidney transplantation; polymorphisms of stromal-derived factor-1 and CXC receptor 4

Genetic interaction between donor and recipient may dictate the impending responses after transplantation. In this study, we evaluated the role of the genetic predispositions of stromal-derived factor-1 (SDF1) [rs1801157 (G>A)] and CXC receptor 4 (CXCR4) [rs2228014 (C>T)] on renal allograft outcomes. A total of 335 pairs of recipients and donors were enrolled. Biopsy-proven acute rejection (BPAR) and long-term graft survival were traced. Despite similar allele frequencies between donors and recipients, minor allele of SDF1 rs1801157 (GA+AA) from donor, not from recipients, has a protective effect on the development of BPAR compared to wild type donor (GG) (P = 0.005). Adjustment for multiple covariates did not affect this result (odds ratio 0.39, 95% C.I 0.20–0.76, P = 0.006). CXCR4 rs2228014 polymorphisms from donor or recipient did not affect the incidence of acute rejection. SDF1 was differentially expressed in renal tubular epithelium with acute rejection according to genetic variations of donor rs1801157 showing higher expressions in the grafts from GG donors. Contrary to the development of BPAR, the presence of minor allele rs1801157 A, especially homozygocity, predisposed poor graft survival (P = 0.001). This association was significant after adjusting for several risk factors (hazard ratio 3.01; 95% C.I = 1.19–7.60; P = 0.020). The allelic variation of recipients, however, was not associated with graft loss. A donor-derived genetic polymorphism of SDF1 has influenced the graft outcome. Thus, the genetic predisposition of donor should be carefully considered in transplantation.

Association of genetic polymorphisms of CXCL12/SDF1 gene and its receptor, CXCR4, to the susceptibility and prognosis of non-small cell lung cancer

BACKGROUND

The aim of this study was to evaluate the relations of chemokine CXCL12, previously known as stromal cell-derived factor-1 (SDF1), and its receptor, CXCR4, gene variants on non-small cell lung cancer (NSCLC) risk and disease severity.

METHODS

Through a case-control study design, genomic DNA samples of 247 NSCLC patients and 328 age and sex-matched controls were subjected to polymerase chain reaction-restriction fragment length polymorphism analysis. The validity of this technique was proven by direct sequencing of amplified products. Statistical analyses were conducted to explore the contribution of polymorphism of the CXCL12/SDF1 gene and CXCR4, in the susceptibility to and prognosis of NSCLC.

RESULTS

Overall, the genotype frequencies of CXCL12/SDF1 gene and CXCR4, were significantly different between lung cancer patients and controls (p<0.0001), and also different between patients with lung cancers of various stages (p<0.0001). Logistic regression analysis revealed that higher odds ratios (ORs) for lung cancer were seen for individuals with CXCL12/SDF1 AA (an OR of 1.95, 95% CI 1.08-3.50, p=0.018), or CXCR4 TT (an OR of 4.71, 95% CI 1.99-11.2, p<0.0001), and for individuals with both CXCL12/SDF1 AA and CXCR4 TT genotypes (an OR of 12.4, 95% CI 1.56-98.3, p=0.002). The patients carrying a homologous AA genotype at CXCL12/SDF1, or a homologous TT genotype at CXCR4, had a tendency to advanced disease and toward poorer prognoses compared with other patients.

CONCLUSION

A significant association between the polymorphisms of CXCL12/SDF1 and CXCR4, and the susceptibility to and prognosis of NSCLC was demonstrated.

Nuclear expression of CXCR4 is associated with advanced colorectal cancer

BACKGROUND AND OBJECTIVES

CXCR4 and its ligand, SDF-1alpha, play an important role in the targeted metastasis of colon cancer. In this study, we analyzed an expression of CXCR4 in clinical samples and showed that SDF-1alpha affected the expression of CXCR4 in colon cancer cells.

MATERIALS AND METHODS

A total of 388 patients with colorectal cancer (CRC) who underwent surgery in Taipei Veterans General Hospital from 2000 to 2004 were included. The expression of CXCR4 in CRC was visualized by immunohistochemistry (anti-CXCR4 mAb, R&D 12G5). HCT116, SW480, and SW620 cells were treated with SDF-1alpha in vitro and the CXCR4 proteins located in the cytoplasmic and nuclear compartments were separated and analyzed with western blotting.

RESULTS

The frequency of cytoplasmic and nuclear expression of CXCR4 in colorectal cancers was 35.6% and 36.9%, respectively. Nuclear but not cytoplasmic expression of CXCR4 was associated with advanced CRC (p < 0.001) and lymphovascular invasion. However, in multivariate analysis, nuclear expression of CXCR4 did not correlate with patients' outcome. In the in vitro study, SDF-1alpha, stimulation of three colorectal carcinoma lines enhanced the CXCR4 nuclear expression.

CONCLUSION

Expression of the CXCR4 plays a role in CRC progression and may be associated with SDF-1alpha stimulation.

Chemokines at the crossroads of tumor-fibroblast interactions that promote malignancy

Cells of the tumor microenvironment play active roles in determining the malignancy phenotype. The host cells and the cancer cells cross-talk via a large variety of soluble factors, whose effects on both partners determine the final outcome of the tumorigenic process. In this review, we focus on the interactions between cancer cells and fibroblasts that are found in their proximity in the growing and progressing tumor and describe the roles of chemokines in mediating such cross-talks. Cancer-associated fibroblasts (CAFs, also termed tumor-associated fibroblasts) were found recently to acquire properties that promote tumor development and metastasis formation, as is also the case for specific members of the chemokine family. In this review, we suggest that there is a bidirectional cross-talk between tumor cells and CAFs, which leads via chemokine activities to increased malignancy. This cross-talk is manifested by the fact that cancer cells release factors that enhance the ability of the fibroblasts to secrete a variety of tumor-promoting chemokines, which then act back on the malignant cells to promote their proliferative, migratory, and invasive properties. The CAF-released chemokines also affect the tumor microenvironment, leading to increased angiogenesis and possibly to an elevated presence of cancer-supporting macrophages in tumors. Here, we describe these bidirectional interactions and the chemokines that are involved in these processes: mainly the CXCL12-CXCR4 pair but also other chemokines, including CCL2, CCL5, CCL7, CXCL8, and CXCL14. The overall findings suggest that chemokines stand at the crossroads of tumor-CAF interactions that lead to increased malignancy in many cancer diseases.