Clinical & Experimental Metastasis

Effect of bisphosphonates on overall survival in subgroups of patients with prostate cancer Abstract Adjuvant therapy with bisphosphonates in prostate cancer is effective in improving bone mineral density and thus reducing fractures and skeletal-related events. We analyzed the effect of bisphosphonates on overall survival (OS) in subgroups of patients with prostate cancer. A systematic literature search was conducted of the PubMed database and the bibliographies of related studies. The long-term OS rates were extracted from every eligible trial. The hazard ratio (HR) was pooled with the fixed effects model, and preplanned subgroup analyses were performed. The search yielded 112 articles, of which 10 articles with 13 patient subgroups met the eligibility criteria. The meta-analysis of all 13 subgroups showed that adjuvant bisphosphonate therapy did not significantly improve OS versus the control group (HR = 0.961, 95% CI 0.899–1.026, p = 0.233) with low heterogeneity (I2 = 13.47%, degrees of freedom = 12, p = 0.336). There was no significant improvement in OS with the addition of bisphosphonates in the major subgroup analyses (metastatic (M1) versus non-metastatic, clodronate versus zoledronic acid, castration-sensitive prostate cancer (CSPC) versus castration-refractory prostate cancer). When the subgroups were further divided, adjuvant bisphosphonate therapy significantly improved OS in patients with CSPC + M1 (HR = 0.874, 95% CI 0.778–0.982, p = 0.023; I2 = 0.0%, degrees of freedom = 3, p = 0.579). Our study demonstrated that bisphosphonates do not significantly improve long-term OS in patients with prostate cancer. However, adjuvant bisphosphonate therapy significantly improves OS in the subgroup of patients with CSPC + M1.

Quantitative assessment of breast cancer liver metastasis expansion with patient-derived xenografts Abstract Advanced breast cancer often spreads to the bone, brain, liver, and lungs. The survival time of a patient with breast cancer liver metastasis is often less than 9 months without treatment. Experimental model systems often focus on the lung as a site of metastatic relapse, and therefore, there is less of an understanding of the biological processes that occur during expansive liver metastasis growth. In these studies, 14 genetically distinct breast cancer patient-derived xenografts (PDXs) were characterized for growth in the liver after portal vein injection of cancer cells. Growth in the liver occurred in 12 of 14 models, and the relative growth rate across the PDXs was overall similar to growth in the mammary gland. Pathological and immunohistochemical analyses revealed that the proliferation rates of metastases were relatively similar as the metastases expanded until the tumors became necrotic, and then slightly lower proliferation rates were observed. There were influxes of macrophages and neutrophils as the metastases increased in size, suggesting these innate immune cells may result in differential responses to therapeutics in micrometastases compared to macrometastases. The development and characterization of these models is important as future studies can utilize this information to determine if targeted therapies can slow the progression of metastatic disease at different stages in the liver.

The extracellular matrix in tumor progression and metastasis Abstract The extracellular matrix (ECM) constitutes the scaffold of tissues and organs. It is a complex network of extracellular proteins, proteoglycans and glycoproteins, which form supramolecular aggregates, such as fibrils and sheet-like networks. In addition to its biochemical composition, including the covalent intermolecular cross-linkages, the ECM is also characterized by its biophysical parameters, such as topography, molecular density, stiffness/rigidity and tension. Taking these biochemical and biophysical parameters into consideration, the ECM is very versatile and undergoes constant remodeling. This review focusses on this remodeling of the ECM under the influence of a primary solid tumor mass. Within this tumor stroma, not only the cancer cells but also the resident fibroblasts, which differentiate into cancer-associated fibroblasts (CAFs), modify the ECM. Growth factors and chemokines, which are tethered to and released from the ECM, as well as metabolic changes of the cells within the tumor bulk, add to the tumor-supporting tumor microenvironment. Metastasizing cancer cells from a primary tumor mass infiltrate into the ECM, which variably may facilitate cancer cell migration or act as barrier, which has to be proteolytically breached by the infiltrating tumor cell. The biochemical and biophysical properties therefore determine the rates and routes of metastatic dissemination. Moreover, primed by soluble factors of the primary tumor, the ECM of distant organs may be remodeled in a way to facilitate the engraftment of metastasizing cancer cells. Such premetastatic niches are responsible for the organotropic preference of certain cancer entities to colonize at certain sites in distant organs and to establish a metastasis. Translational application of our knowledge about the cancer-primed ECM is sparse with respect to therapeutic approaches, whereas tumor-induced ECM alterations such as increased tissue stiffness and desmoplasia, as well as breaching the basement membrane are hallmark of malignancy and diagnostically and histologically harnessed.

Circulating microRNAs in head and neck cancer: a scoping review of methods Abstract Circulating microRNAs have been described as head and neck cancer biomarkers in multiple anatomical subsites including the oral cavity, nasopharynx, larynx, salivary glands and the skin. While there is an expanding volume of published literature showing the significance of individual or panels of microRNAs, the clinical validation of candidate biomarkers is lacking. The various methods used to collect, store, process and interpret these microRNAs are likely introducing bias and contributing to the inconsistent results. A systematic scoping review was conducted using PRISMA standards to identify published English literature between 2007 and 2018. Pubmed and EMBASE databases were searched using specific keyword combinations related to head and neck cancer, circulating samples (whole blood, plasma or serum) and microRNA. Following the title and abstract review, two primary authors appraised the articles for their suitability to include in the review based on the detail of methodological descriptions. Thirty suitable articles were identified relating to nasopharyngeal carcinoma, oral cavity, oropharyngeal and laryngeal squamous cell carcinoma as well as primary salivary gland malignancies. Comprehensive methodological analysis identified poor reporting of detailed methodology, variations in collection, storage, pre-processing, RNA isolation and relative quantification including normalisation method. We recommend standardising the pre-processing, RNA isolation, normalisation and relative quantitation steps at biomarker discovery phase. Such standardisation would allow for bias minimisation and effective progression into clinical validation phases.

Promoter hypermethylation-mediated downregulation of tumor suppressor gene SEMA3B and lncRNA SEMA3B-AS1 correlates with progression and prognosis of esophageal squamous cell carcinoma Abstract Frequent deletions of tumor-suppressor genes at chromosome 3p21.3 have been detected in esophageal squamous cell carcinoma (ESCC). As a candidate tumor suppressor gene, semaphorin 3B (SEMA3B) is located at 3p21.3 and is frequently inactivated in several tumors. However, the role and inactivation mechanisms of SEMA3B and its antisense long non-coding RNA (lncRNA) SEMA3B-AS1 in the carcinogenesis of ESCC have not been fully elucidated. The present study was conducted to investigate the role, epigenetic inactivation mechanisms, and prognostic value of SEMA3B and SEMA3B-AS1 in ESCC tumorigenesis and prognosis. Frequent downregulation of SEMA3B and SEMA3B-AS1 was detected in esophageal cancer cells and ESCC tissues, and the expression level of SEMA3B and SEMA3B-AS1 in ESCC tissues was correlated with TNM stage and lymph node metastasis. SEMA3B and SEMA3B-AS1 shared the same CpG island in the promoter region and the expression of both genes might be regulated by the promoter methylation status. Furthermore, transcription factor Sp1 activated SEMA3B or SEMA3B-AS1 transcription and the promoter hypermethylation of SEMA3B and SEMA3B-AS1 influenced Sp1 binding ability. Moreover, over-expression of SEMA3B and SEMA3B-AS1 suppressed the viability and invasion of esophageal cancer cells in vitro. SEMA3B-AS1 influenced the protein expression of SEMA3B. SEMA3B or SEMA3B-AS1 expression and promoter methylation status were correlated with ESCC patients' survival. Thus, these findings suggest that SEMA3B and SEMA3B-AS1 may act as tumor suppressors and may serve as potential targets for antitumor therapy.

Identification of canonical NFκB (C-NFκB) pathway in uveal melanoma and their relation with patient outcome Abstract Inflammation in uveal melanoma (UM) is linked to a bad prognosis. It is rare type of cancer, of which the metastases are usually fatal within a year. Infiltration with an inflammatory infiltrate increases with disease progression but does not seem to inhibit metastasis. The Canonical NFκB (C-NFκB) pathway is known to play a crucial role in tumor inflammation. We therefore, studied the expression of canonical NFκB proteins and their prognostic relevance in UM. Our study evaluated the expression of C-NFκB proteins (p65, p50, and c-Rel) by using immunohistochemistry on sections from 75 formalin-fixed UM. Activation of the NFκB subunit was determined on fresh tumor specimens by measuring the DNA-binding activity in nuclei using an NFκB ELISA assay. Real-time PCR was performed on frozen material on 58 tumors. The presence of native C-NFκB heterodimers (p65/p50 and c-Rel/p50) was confirmed by co-immunoprecipitation followed by Western blotting. We observed a high nuclear immunoreactivity of p65, p50, and c-Rel proteins in 54, 60 and 41% UM cases, respectively. Expression of C-NFκB proteins significantly correlated with parameters which are related to the inflammatory environment of UM. Nuclear immunoreactivity of p65 and p50 was associated with lower patient survival (p = 0.041; p = 0.048) while c-Rel was not. Our finding reveals that C-NFκB proteins expressed are more often in UM with inflammation than those without inflammation. Activation of the canonical NFκB pathway is more frequent in high risk UM patients. These observations might help to understand the behaviour of high risk tumors, with upregulation of C-NFκB proteins contributing to tumor aggressiveness.

Non-canonical roles for metabolic enzymes and intermediates in malignant progression and metastasis Abstract Metabolic alterations are established as a hallmark of cancer. Such hallmark changes in cancer metabolism are characterized by reprogramming of energy-producing pathways and increases in the generation of biosynthetic intermediates to meet the needs of rapidly proliferating tumor cells. Various metabolic phenotypes such as aerobic glycolysis, increased glutamine consumption, and lipolysis have also been associated with the process of metastasis. However, in addition to the energy and biosynthetic alterations, a number of secondary functions of enzymes and metabolites are emerging that specifically contribute to metastasis. Here, we describe atypical intracellular roles of metabolic enzymes, extracellular functions of metabolic enzymes, roles of metabolites as signaling molecules, and epigenetic regulation mediated by altered metabolism, all of which can affect metastatic progression. We highlight how some of these mechanisms are already being exploited for therapeutic purposes, and discuss how others show similar potential.

Discovery of CCL18 antagonist blocking breast cancer metastasis Abstract Our previous studies have proved that CCL18 is the most secreted chemokine in breast cancer microenvironment by tumor associated macrophages (TAMs). CCL18 promotes breast cancer invasiveness by binding to its cognate receptor PITPNM3 and activating the downstream signaling pathways. The high level of CCL18 in serum or tumor stroma is associated with tumor metastasis and poor patients overall survival. In this study, we identify an effective small molecular compound (SMC) to antagonize the effect of CCL18. We screen more than 1000 SMCs from Sun Yat-sen University SMC library and select 15 top scored SMCs by using computer-aided virtual screening based on the structure of CCL18. Then in vitro cell migration assay narrows down the selected 15 SMCs to the most effective SMC-21598. We find 10 µM SMC-21598 significantly inhibits CCL18-induced breast cancer cells adherence, invasiveness, and migration. Our further surface plasmon resonance (SPR), fluorescence spectroscopy and isothermal titration calorimetry (ITC) assays reveal that SMC-21598 binds tightly to CCL18, which blocks the binding of CCL18 with its receptor PITPNM3. The in vivo animal experiments show that SMC-21598 doesn't significantly affect xenografts growth, but inhibits lung metastasis. Our study provides a potential lead compound to antagonize CCL18 function. It would be of great significance to develop SMC drugs to ameliorate breast cancer metastasis and prolong patients' survival.

Histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy Abstract Colorectal liver metastases (CRLM) exhibit distinct histopathological growth patterns (HGPs) that are indicative of prognosis following surgical treatment. This study aims to assess the reliability and replicability of this histological biomarker. Within and between metastasis HGP concordance was analysed in patients who underwent surgery for CRLM. An independent cohort was used for external validation. Within metastasis concordance was assessed in CRLM with ≥ 2 tissue blocks. Similarly, concordance amongst multiple metastases was determined in patients with ≥ 2 resected CRLM. Diagnostic accuracy [expressed in area under the curve (AUC)] was compared by number of blocks and number of metastases scored. Interobserver agreement (Cohen's k) compared to the gold standard was determined for a pathologist and a PhD candidate without experience in HGP assessment after one and two training sessions. Both the within (95%, n = 825) and the between metastasis (90%, n = 363) HGP concordance was high. These results could be replicated in the external validation cohort with a within and between metastasis concordance of 97% and 94%, respectively. Diagnostic accuracy improved when scoring 2 versus 1 blocks(s) or CRLM (AUC = 95.9 vs. 97.7 [p = 0.039] and AUC = 96.5 vs. 93.3 [p = 0.026], respectively), but not when scoring 3 versus 2 blocks or CRLM (both p > 0.2). After two training sessions the interobserver agreement for both the pathologist and the PhD candidate were excellent (k = 0.953 and k = 0.951, respectively). The histopathological growth patterns of colorectal liver metastasis exhibit little heterogeneity and can be determined with a high diagnostic accuracy, making them a reliable and replicable histological biomarker.

Metastasis is impaired by endothelial-specific Dll4 loss-of-function through inhibition of epithelial-to-mesenchymal transition and reduction of cancer stem cells and circulating tumor cells Abstract Systemic inhibition of Dll4 has been shown to thoroughly reduce cancer metastasis. The exact cause of this effect and whether it is endothelial mediated remains to be clarified. Therefore, we proposed to analyze the impact of endothelial Dll4 loss-of-function on metastasis induction on three early steps of the metastatic process, regulation of epithelial-to-mesenchymal transition (EMT), cancer stem cell (CSC) frequency and circulating tumor cell (CTC) number. For this, Lewis Lung Carcinoma (LLC) cells were used to model mouse tumor metastasis in vivo, by subcutaneous transplantation into endothelial-specific Dll4 loss-of-function mice. We observed that endothelial-specific Dll4 loss-of-function is responsible for the tumor vascular regression that leads to the reduction of tumor burden. It induces an increase in tumoral blood vessel density, but the neovessels are poorly perfused, with increased leakage and reduced perivascular maturation. Unexpectedly, although hypoxia was increased in the tumor, the number and burden of macro-metastasis was significantly reduced. This is likely to be a consequence of the observed reduction in both EMT and CSC numbers caused by the endothelial-specific Dll4 loss-of-function. This multifactorial context may explain the concomitantly observed reduction of the circulating tumor cell count. Furthermore, our results suggest that endothelial Dll4/Notch-function mediates tumor hypoxia-driven increase of EMT. Therefore, it appears that endothelial Dll4 may constitute a promising target to prevent metastasis.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com