Organ-specific metastatic tumor cell adhesion and extravasation of colon carcinoma cells with different metastatic potential

A nomogram for predicting colorectal cancer liver metastasis using circulating tumor cells from the first drainage vein

PURPOSE

To use circulating tumor cells (CTC) from the first drainage vein (FDV) of the primary lesion and other clinically relevant parameters to construct a nomogram for predicting liver metastasis in colorectal cancer (CRC) patients, and to provide a theoretical basis for clinical diagnosis and treatment.

METHODS

Information from 343 CRC patients was collected and a database was established. Multivariate logistic analysis was used to identify independent factors for colorectal cancer liver metastasis(mCRC) and nomograms were constructed. Receiver operating characteristic curves(ROC), calibration plots, and decision curve analysis (DCA) were used to assess discrimination, agreement with actual risk, and the clinical utility of the prediction model, respectively.

RESULT

CTC levels in FDV were significantly higher in patients with liver metastasis than in those without liver metastasis. Logistic multivariate analysis showed that vascular invasion, T stage, carcinoembryonic antigen (CEA), CA19-9, and CTC could be used as predictors to construct nomograms. The nomograms showed good discriminatory ability in predicting mCRC, with area under the curve (AUC) values of 0.871 [95 % CI: 0.817-0.924) and 0.891 (95 % CI: 0.817-0.964) for the training and validation sets, respectively.] The calibration curves of both the training and validation sets showed that the model was effective in predicting the probability of mCRC. DCA was used to evaluate this predictive model and showed good net clinical benefit.

CONCLUSION

We developed and validated a nomogram model based on the combination of CTC in the FDV with other clinical parameters to better predict the occurrence of mCRC.

Utilizing machine learning algorithms for predicting risk factors for bone metastasis from right-sided colon carcinoma after complete mesocolic excision: a 10-year retrospective multicenter study

BACKGROUND

Bone metastasis (BM) occurs when colon cancer cells disseminate from the primary tumor site to the skeletal system via the bloodstream or lymphatic system. The emergence of such bone metastases typically heralds a significantly poor prognosis for the patient. This study's primary aim is to develop a machine learning model to identify patients at elevated risk of bone metastasis among those with right-sided colon cancer undergoing complete mesocolonectomy (CME).

PATIENTS AND METHODS

The study cohort comprised 1,151 individuals diagnosed with right-sided colon cancer, with a subset of 73 patients presenting with bone metastases originating from the colon. We used univariate and multivariate regression analyses as well as four machine learning algorithms to screen variables for 38 characteristic variables such as patient demographic characteristics and surgical information. The study employed four distinct machine learning algorithms, namely, extreme gradient boosting (XGBoost), random forest (RF), support vector machine (SVM), and k-nearest neighbor algorithm (KNN), to develop the predictive model. Additionally, the model was assessed using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA), while Shapley additive explanation (SHAP) was utilized to visualize and analyze the model.

RESULTS

The XGBoost algorithm performed the best performance among the four prediction models. In the training set, the XGBoost algorithm had an area under curve (AUC) value of 0.973 (0.953-0.994), an accuracy of 0.925 (0.913-0.936), a sensitivity of 0.921 (0.902-0.940), and a specificity of 0.908 (0.894-0.922). In the validation set, the XGBoost algorithm had an AUC value of 0.922 (0.833-0.995), an accuracy of 0.908 (0.889-0.926), a sensitivity of 0.924 (0.873-0.975), and a specificity of 0.883 (0.810-0.956). Furthermore, the AUC value of 0.83 for the external validation set suggests that the XGBoost prediction model possesses strong extrapolation capabilities. The results of SHAP analysis identified alkaline phosphatase (ALP) levels, tumor size, invasion depth, lymph node metastasis, lung metastasis, and postoperative neutrophil-to-lymphocyte ratio (NLR) levels as significant risk factors for BM from right-sided colon cancer subsequent to CME.

CONCLUSION

The prediction model for BM from right-sided colon cancer developed using the XGBoost machine learning algorithm in this study is both highly precise and clinically valuable.

Striated muscle: an inadequate soil for cancers

Many organs of the body are susceptible to cancer development. However, striated muscles-which include skeletal and cardiac muscles-are rarely the sites of primary cancers. Most deaths from cancer arise due to complications associated with the development of secondary metastatic tumours, for which there are few effective therapies. However, as with primary cancers, the establishment of metastatic tumours in striated muscle accounts for a disproportionately small fraction of secondary tumours, relative to the proportion of body composition. Examining why primary and metastatic cancers are comparatively rare in striated muscle presents an opportunity to better understand mechanisms that can influence cancer cell biology. To gain insights into the incidence and distribution of muscle metastases, this review presents a definitive summary of the 210 case studies of metastasis in muscle published since 2010. To examine why metastases rarely form in muscles, this review considers the mechanisms currently proposed to render muscle an inhospitable environment for cancers. The "seed and soil" hypothesis proposes that tissues' differences in susceptibility to metastatic colonization are due to differing host microenvironments that promote or suppress metastatic growth to varying degrees. As such, the "soil" within muscle may not be conducive to cancer growth. Gaining a greater understanding of the mechanisms that underpin the resistance of muscles to cancer may provide new insights into mechanisms of tumour growth and progression, and offer opportunities to leverage insights into the development of interventions with the potential to inhibit metastasis in susceptible tissues.

Functional Proteomics Characterization of the Role of SPRYD7 in Colorectal Cancer Progression and Metastasis

SPRY domain-containing protein 7 (SPRYD7) is a barely known protein identified via spatial proteomics as being upregulated in highly metastatic-to-liver KM12SM colorectal cancer (CRC) cells in comparison to its isogenic poorly metastatic KM12C CRC cells. Here, we aimed to analyze SPRYD7's role in CRC via functional proteomics. Through immunohistochemistry, the overexpression of SPRYD7 was observed to be associated with the poor survival of CRC patients and with an aggressive and metastatic phenotype. Stable SPRYD7 overexpression was performed in KM12C and SW480 poorly metastatic CRC cells and in their isogenic highly metastatic-to-liver-KM12SM-and-to-lymph-nodes SW620 CRC cells, respectively. Upon upregulation of SPRYD7, in vitro and in vivo functional assays confirmed a key role of SPRYD7 in the invasion and migration of CRC cells and in liver homing and tumor growth. Additionally, transient siRNA SPRYD7 silencing allowed us to confirm in vitro functional results. Furthermore, SPRYD7 was observed as an inductor of angiogenesis. In addition, the dysregulated SPRYD7-associated proteome and SPRYD7 interactors were elucidated via 10-plex TMT quantitative proteins, immunoproteomics, and bioinformatics. After WB validation, the biological pathways associated with the stable overexpression of SPRYD7 were visualized. In conclusion, it was demonstrated here that SPRYD7 is a novel protein associated with CRC progression and metastasis. Thus, SPRYD7 and its interactors might be of relevance in identifying novel therapeutic targets for advanced CRC.

Variant Characterization of a Representative Large Pedigree Suggests "Variant Risk Clusters" Convey Varying Predisposition of Risk to Lynch Syndrome

Recently, worldwide incidences of young adult aggressive colorectal cancer (CRC) have rapidly increased. Of these incidences diagnosed as familial Lynch syndrome (LS) CRC, outcomes are extremely poor. In this study, we seek novel familial germline variants from a large pedigree Tunisian family with 12 LS-affected individuals to identify putative germline variants associated with varying risk of LS. Whole-genome sequencing analysis was performed to identify known and novel germline variants shared between affected and non-affected pedigree members. SNPs, indels, and structural variants (SVs) were computationally identified, and their oncological influence was predicted using the Genetic Association of Complex Diseases and Disorders, OncoKB, and My Cancer Genome databases. Of 94 germline familial variants identified with predicted functional impact, 37 SNPs/indels were detected in 28 genes, 2 of which (MLH1 and PRH1-TAS2R14) have known association with CRC and 4 others (PPP1R13B, LAMA5, FTO, and NLRP14) have known association with non-CRC cancers. In addition, 48 of 57 identified SVs overlap with 43 genes. Three of these genes (RELN, IRS2, and FOXP1) have a known association with non-CRC digestive cancers and one (RRAS2) has a known association with non-CRC cancer. Our study identified 83 novel, predicted functionally impactful germline variants grouped in three "variant risk clusters" shared in three familiarly associated LS groups (high, intermediate and low risk). This variant characterization study demonstrates that large pedigree investigations provide important evidence supporting the hypothesis that different "variant risk clusters" can convey different mechanisms of risk and oncogenesis of LS-CRC even within the same pedigree.

Circumventing drug resistance through a CK2-targeted combination via attenuating endogenous ahr-TLS-promoted genomic instability in human colorectal cancer cells

As anchoring Casein Kinase 2 (CK2) in several human tumors, DN701 as a novel CK2 inhibitor was applied to reverse chemo-resistance via its antitumor effect synergized with oxaliplatin. Recently, translesion DNA synthesis (TLS) has attracted our attention for its association with chemo-resistance, as demonstrated by previous clinical data. The in vitro cell-based properties supported that oxaliplatin combined with DN701 could reverse drug resistance via blockading CK2-mediated aryl hydrocarbon receptor (AhR) and translesion DNA synthesis (TLS)-induced DNA damage repair. Moreover, pharmacologic or genetic inhibition on REV3L (Protein reversion less 3-like) greatly impaired TLS-induced genomic instability. Mechanistically, combination of oxaliplatin with DN701 was found to inhibit CK2 expression and AhR-TLS-REV3L axis signaling, implying the potential decrease of genomic instability. In addition, the combination of oxaliplatin with DN701 could reduce CK2-AhR-TLS-related genomic instability, leading to potent antitumor effects in vivo. Our study presents an underlying mechanism that DN701 could attenuate tumoral chemo-resistance via decaying CK2-mediated AhR and TLS genomic instability, suggesting a potential cancer chemotherapeutic modality to prolong survival in chemo-resistant patients.

Robot-assisted surgery for rectal cancer with solitary sacrococcygeal metastasis after neoadjuvant chemoradiotherapy: A case report

An 81-year-old man was referred to our hospital for anal bleeding. Colonoscopy revealed a type 3 tumor at the upper rectum and biopsy showed adenocarcinoma. An enhanced circumferential lesion at the upper rectum and a solitary soft-tissue shadow at the fifth sacral vertebra to the coccyx were detected on abdominal magnetic resonance imaging. Fluorodeoxyglucose uptake was observed at the same sites on positron emission tomography. The patient was diagnosed with rectal cancer with isolated sacrococcygeal metastasis and was treated with neoadjuvant chemoradiotherapy followed by robotic surgery. Hartmann's operation was performed in the lithotomy position. The left internal iliac artery and vein were then divided. The internal pudendal artery and vein, the piriformis muscle, and sacrospinous ligament were also divided while preserving the lumbosacral trunk. The scheduled transection line of the sacral surface was fully exposed to prevent massive bleeding during sacrectomy. The dorsal surface of the sacrum was then exposed in the prone position and communicated with the pelvic space. The sacrum was transected at the superior margin of S3 and a specimen was extracted. Pathological findings revealed the infiltration of cancer cells in the sacrococcygeal specimen. The postoperative course was uneventful and the patient was discharged on postoperative day 13.

Intravital imaging to study cancer progression and metastasis

Navigation through the bulk tumour, entry into the blood vasculature, survival in the circulation, exit at distant sites and resumption of proliferation are all steps necessary for tumour cells to successfully metastasize. The ability of tumour cells to complete these steps is highly dependent on the timing and sequence of the interactions that these cells have with the tumour microenvironment (TME), including stromal cells, the extracellular matrix and soluble factors. The TME thus plays a major role in determining the overall metastatic phenotype of tumours. The complexity and cause-and-effect dynamics of the TME cannot currently be recapitulated in vitro or inferred from studies of fixed tissue, and are best studied in vivo, in real time and at single-cell resolution. Intravital imaging (IVI) offers these capabilities, and recent years have been a time of immense growth and innovation in the field. Here we review some of the recent advances in IVI of mammalian models of cancer and describe how IVI is being used to understand cancer progression and metastasis, and to develop novel treatments and therapies. We describe new techniques that allow access to a range of tissue and cancer types, novel fluorescent reporters and biosensors that allow fate mapping and the probing of functional and phenotypic states, and the clinical applications that have arisen from applying these techniques, reporters and biosensors to study cancer. We finish by presenting some of the challenges that remain in the field, how to address them and future perspectives.

Survival benefit of primary and metastatic tumor resection for colon cancer with liver metastases: A population based, propensity score-matched study

Background

Colon cancer remains one of the most common malignancies and we aimed to evaluate whether surgery has an effect on the survival of metastatic colon patients.

Methods

We analyzed 7,583 metastatic colon patients from the Surveillance, Epidemiology, between January 2010 and December 2015. Using Cox proportional hazards models and Kaplan-Meier curves, the overall survival rate (OS) and cancer-specific survival rate and End Results (SEER) registry (CSS) months (m) were evaluated with corresponding 95% confidence intervals (95% CIs). Propensity score matching (PSM) was performed to adjust for potential baseline confounding of all comparison groups.

Results

In general, receiving both primary and metastatic tumor resection (PMTR) remarkably improved OS and CSS compared with only primary tumor resection (PTR) after PS matching (PSM) (P < 0.05), with a significantly improved OS (HR = 0.74, 95%CI = 0.69–0.80) and CSS (HR = 0.71, 95%CI = 0.66–0.76) in all stage M1 colon patients. The stratification analysis indicated a significant difference between OS and CSS in M1a and M1b stages. After PSM, PMTR was found to be associated with remarkably improved OS and CSS for patients with liver metastases but not associated with OS and CSS of patients with lung metastases in both M1a and M1b stage.

Conclusions

The results from this large SEER cohort supported PMTR might improve the survival of colon patients with liver metastases on the basis of chemotherapy.

Predictive Efficacy of Circulating Tumor Cells in First Drainage Vein Blood from Patients with Colorectal Cancer liver Metastasis

Circulating tumor cells (CTCs) are associated with metastasis. However, the low rate of detection of CTCs in peripheral vein blood (PVB) limits their clinical application. In this study, we observed higher positive rates of CTC in first drainage vein blood (FDVB) relative to peripheral venous blood (P < 0.001). Moreover, the CTC content was related to liver metastasis, T stage and CA19-9 levels. Our collective data suggest that CTCs in FDVB have good predictive utility for risk of liver metastasis of colorectal cancer (CRC), in particular, metachronous liver metastasis.

Cross Talk Between Macrophages and Cancer Cells in the Bone Metastatic Environment

The skeleton is a common site for cancer metastases with the bone microenvironment providing the appropriate conditions for cancer cell colonization. Once in bone, cancer cells effectively manipulate their microenvironment to support their growth and survival. Despite previous efforts to improve treatment modalities, skeletal metastases remain with poor prognoses. This warrants an improved understanding of the mechanisms leading to bone metastasis that will aid development of effective treatments. Macrophages in the tumor microenvironment are termed tumor associated macrophages (TAMs) and their crosstalk with cancer cells is critical in regulating tumorigenicity in multiple cancers. In bone metastases, this crosstalk is also being increasingly implicated but the specific signaling pathways remain incompletely understood. Here, we summarize the reported functions, interactions, and signaling of macrophages with cancer cells during the metastatic cascade to bone. Specifically, we review and discuss how these specific interactions impact macrophages and their profiles to promote tumor development. We also discuss the potential of targeting this crosstalk to inhibit disease progression. Finally, we identify the remaining knowledge gaps that will need to be addressed in order to fully consider therapeutic targeting to improve clinical outcomes in cancer patients.

Flavokawain C exhibits anti-tumor effects on in vivo HCT 116 xenograft and identification of its apoptosis-linked serum biomarkers via proteomic analysis

Chalcones and their derivatives belong to the flavonoid family. They have been extensively studied for their anticancer properties and some have been approved for clinical use. In this study, the in vivo anti-tumor activity of flavokawain C (FKC), a naturally occurring chalcone found in Kava (Piper methysticum Forst) was evaluated in HCT 116 cells (colon carcinoma). We also attempted to identify potential biomarkers and/or molecular targets in serum with applicability in predicting treatment outcome. The anti-tumor effects and toxicity of FKC were assessed using the xenograft nude mice model. Cisplatin was used as positive control. The anti-proliferative and apoptotic activities were then evaluated in tumor tissues treated with FKC. Furthermore, two-dimensional electrophoresis (2-DE) followed by protein identification using MALDI-TOF/TOF-MS/MS was performed to compare the serum proteome profiles between healthy nude mice and nude mice bearing HCT 116 tumor treated with vehicle solution and FKC, respectively. Our results showed that FKC treatment significantly inhibited HCT 116 tumor growth. In vivo toxicity studies showed that administration of FKC did not cause damage to major organs and had no significant effect on body weight. FKC was found to induce apoptosis in tumor, and this was associated with increased expression of cleaved caspase-3 and decreased expression of Ki67 in tumor tissues. Our proteomic analysis identified five proteins that changed in abundance - Ig mu chain C region (secreted form), GRP78, hemopexin, kininogen-1 and apolipoprotein E. Overall, our findings demonstrated the potential of FKC as an anti-cancer agent for the treatment of colon carcinoma.

Survival outcome and prognostic factors for colorectal cancer with synchronous bone metastasis: a population-based study

Prognostic factors of synchronous bone metastatic colorectal cancer (CRC) are still undetermined. We aimed to investigate survival outcome and prognostic factors of patients with synchronous bone metastatic CRC. Information of patients with synchronous bone metastatic CRC were obtained from the Surveillance, Epidemiology, and End Results (SEER) and West China Hospital (WCH) databases. Cases from SEER database composed construction cohort, while cases from WCH database were used as validation cohort. A novel nomogram was constructed to predict individual survival probability based on Cox regression model. The performance of the nomogram was internally and externally validated using calibration curves and concordance index (C-index). Three hundred and eighty-one patients from SEER database were eligible. The median disease specific OS was 9.0 months (95% confidence interval [CI]: 7.3-10.7 months). Multivariate Cox analysis identified seven independent prognostic factors including histological type, differentiation grade, T stage of primary tumor, CEA level, systemic chemotherapy, combined with liver metastasis and combined with lung metastasis. A novel nomogram was established based on these variables. In the internal validation, the C-index (0.72, 95% CI 0.69-0.75) and calibration curve indicated well performance of this nomogram at predicting survival outcome in bone metastatic CRC. In the external validation, the C-index was 0.57 (95% CI 0.46-0.68). The prognosis of synchronous bone metastatic CRC is very poor. Histological type, differentiation grade, T stage of primary tumor, CEA level, systemic chemotherapy, combined with liver metastasis and combined with lung metastasis are independent prognostic factors. Further study is warranted to confirm the practicality of the prognostic nomogram.

Multidrug transporter MRP4/ABCC4 as a key determinant of pancreatic cancer aggressiveness

Recent findings show that MRP4 is critical for pancreatic ductal adenocarcinoma (PDAC) cell proliferation. Nevertheless, the significance of MRP4 protein levels and function in PDAC progression is still unclear. The aim of this study was to determine the role of MRP4 in PDAC tumor aggressiveness. Bioinformatic studies revealed that PDAC samples show higher MRP4 transcript levels compared to normal adjacent pancreatic tissue and circulating tumor cells express higher levels of MRP4 than primary tumors. Also, high levels of MRP4 are typical of high-grade PDAC cell lines and associate with an epithelial-mesenchymal phenotype. Moreover, PDAC patients with high levels of MRP4 depict dysregulation of pathways associated with migration, chemotaxis and cell adhesion. Silencing MRP4 in PANC1 cells reduced tumorigenicity and tumor growth and impaired cell migration. Transcriptomic analysis revealed that MRP4 silencing alters PANC1 gene expression, mainly dysregulating pathways related to cell-to-cell interactions and focal adhesion. Contrarily, MRP4 overexpression significantly increased BxPC-3 growth rate, produced a switch in the expression of EMT markers, and enhanced experimental metastatic incidence. Altogether, our results indicate that MRP4 is associated with a more aggressive phenotype in PDAC, boosting pancreatic tumorigenesis and metastatic capacity, which could finally determine a fast tumor progression in PDAC patients.

Cervical bone pain revealing a bone metastatic colon cancer: A case report

Colorectal cancer (CRC) is one of the most common malignancies worldwide, with common sites of metastases including abdominal lymph nodes, the liver and lungs. Bone metastases are known to be relatively rare sites of metastasis. The present study reported a patient with advanced colorectal cancer and metastatic colorectal cancer (mCRC) with atypical metastases presentation. Bone mCRCs were not frequent and presented a poor prognosis in the present case. It was concluded that further studies are required to clarify the pathogenesis of bone metastases, to improve the management and treatment of patients.

Metastatic colorectal carcinoma initially diagnosed by bone marrow biopsy: a case report and literature review

BACKGROUND

Colorectal carcinoma still represents a global health burden despite the advances in its management. The most common sites of distant metastasis from colorectal carcinoma are hepatic and pulmonary metastases while metastases are rarely reported to affect the bone marrow.

CASE PRESENTATION

We report a 33-year-old female patient who presented with fever of unknown origin, bone aches limited to the lower back and pelvis, and pancytopenia. She was diagnosed by a bone marrow biopsy as a case of metastatic rectosigmoid carcinoma. Serum tumor markers were within normal ranges; CT, MRI, and colonoscopy confirmed the presence of malignant rectosigmoid mass with bone and ovarian metastases.

CONCLUSION

Though being rare, bone marrow metastasis should be suspected in colorectal carcinoma cases with abnormalities in peripheral blood count.

Localization of Rolling and Firm-Adhesive Interactions Between Circulating Tumor Cells and the Microvasculature Wall

INTRODUCTION

The adhesion of tumor cells to vessel wall is a critical stage in cancer metastasis. Firm adhesion of cancer cells is usually followed by their extravasation through the endothelium. Despite previous studies identifying the influential parameters in the adhesive behavior of the cancer cell to a planer substrate, less is known about the interactions between the cancer cell and microvasculature wall and whether these interactions exhibit organ specificity. The objective of our study is to characterize sizes of microvasculature where a deformable circulating cell (DCC) would firmly adhere or roll over the wall, as well as to identify parameters that facilitate such firm adherence and underlying mechanisms driving adhesive interactions.

METHODS

A three-dimensional model of DCCs is applied to simulate the fluid-structure interaction between the DCC and surrounding fluid. A dynamic adhesion model, where an adhesion molecule is modeled as a spring, is employed to represent the stochastic receptor-ligand interactions using kinetic rate expressions.

RESULTS

Our results reveal that both the cell deformability and low shear rate of flow promote the firm adhesion of DCC in small vessels ( < 10 μ m ). Our findings suggest that ligand-receptor bonds of PSGL-1-P-selectin may lead to firm adherence of DCC in smaller vessels and rolling-adhesion of DCC in larger ones where cell velocity drops to facilitate the activation of integrin-ICAM-1 bonds.

CONCLUSIONS

Our study provides a framework to predict accurately where different DCC-types are likely to adhere firmly in microvasculature and to establish the criteria predisposing cancer cells to such firm adhesion.

The Use of Microfluidic Platforms to Probe the Mechanism of Cancer Cell Extravasation

Powerful experimental tools have contributed a wealth of novel insight into cancer etiology from the organ to the subcellular levels. However, these advances in understanding have outpaced improvements in clinical outcomes. One possible reason for this shortcoming is the reliance on animal models that do not fully replicate human physiology. An alternative in vitro approach that has recently emerged features engineered microfluidic platforms to investigate cancer progression. These devices allow precise control over cellular components, extracellular constituents, and physical forces, while facilitating detailed microscopic analysis of the metastatic process. This review focuses on the recent use of microfluidic platforms to investigate the mechanism of cancer cell extravasation.

The Long-lasting Radioprotective Effect of Caffeic Acid in Mice Exposed to Total Body Irradiation by Modulating Reactive Oxygen Species Generation and Hematopoietic Stem Cell Senescence-Accompanied Long-term Residual Bone Marrow Injury

Total body irradiation (TBI) serves as an effectively curative therapy for cancer patients and adversely causes long-term residual bone marrow (BM) injury with premature senescence of hematopoietic stem cells (HSCs), which is mediated by increased production of reactive oxygen species (ROS). In the present study, we investigated how the exposure time of TBI in a mouse model affects HSCs and whether the treatment of caffeic acid (CA), a known dietary phenolic antioxidant, has a radioprotective effect. Single (S)-TBI at a sublethal dose (5 Gy) caused relatively higher induction of mitochondrial ROS and senescence-related factors in HSCs than those in hematopoietic progenitor cells (HPCs) and Lineage^-Sca-1⁺c-Kit⁺ (LSK) cells, as well as reduced clonogenic formation and donor cell-derived reconstituting capacity. Repetitive double (D)-TBI (two months after the S-TBI at a dose of 5Gy) further weakened HSPC function via mitochondrial ROS accumulation and senescence-associated β-galactosidase (SA-β-gal) activity. Oral administration of CA (20 mg/kg) five times before and once immediately after TBI ameliorated ROS generation and TBI-induced HSC senescence and its radioprotective effect was long lasting in S-TBI mice but not in D-TBI mice. Further, supplementation of CA also induced apoptotic cell death of colon cancer cells. Collectively, these findings indicate that CA has a dual effect, ameliorating HSC senescence-accompanied long-term BM injury in S-TBI mice and stimulating apoptotic cell death of colon cancer cells.

Observations on Solitary Versus Multiple Isolated Pancreatic Metastases of Renal Cell Carcinoma: Another Indication of a Seed and Soil Mechanism?

Isolated pancreas metastases are a rare type of metastasis of renal cell carcinoma, characterized by the presence of pancreatic metastases, while all other organs remain unaffected. In a previous study, we determined arguments from the literature which (a) indicate a systemic-haematogenic metastasis route (uniform distribution of the metastases across the pancreas and independence of the metastatic localization in the pancreas of the side of the renal carcinoma); and (b) postulate a high impact of a seed and soil mechanism (SSM) on isolated pancreatic metastasis of renal cell carcinoma (isPM) as an explanation for exclusive pancreatic metastases, despite a systemic haematogenous tumor cell embolization. The objective of the study presented was to search for further arguments in favor of an SSM with isPM. For that purpose, the factor's histology, grading, and singular/multiple pancreas metastases were analyzed on the basis of 814 observations published up to 2018. While histology and grading allowed for no conclusions regarding the importance of an SSM, the comparison of singular/multiple pancreas metastases produced arguments in favor of an SSM: 1. The multiple pancreas metastases observed in 38.1% prove that multiple tumor cell embolisms occur with isPM, the exclusive "maturation" of which in the pancreas requires an SSM; 2. The survival rates (SVR), which are consistent with singular and multiple pancreas metastases (despite the higher total tumor load with the latter), prove that the metastasized tumor cells are not able to survive in all other organs because of an SSM, which results in identical SVR when the pancreatic foci are treated adequately.

Immunological Regulation of Vascular Inflammation During Cancer Metastasis

Metastasis is the predominant cause of cancer-related mortality, despite being a highly inefficient process overall. The vasculature is the gatekeeper for tumor cell seeding within the secondary tissue microenvironment—the rate limiting step of the metastatic cascade. Therefore, factors that regulate vascular physiology dramatically influence cancer outcomes. There are a myriad of physiologic circumstances that not only influence the intrinsic capacity of tumor cells to cross the endothelial barrier, but also that regulate vascular inflammation and barrier integrity to enable extravasation into the metastatic niche. These processes are highly dependent on inflammatory cues largely initiated by the innate immune compartment, that are meant to help re-establish tissue homeostasis, but instead become hijacked by cancer cells. Here, we discuss the scientific advances in understanding the interactions between innate immune cells and the endothelium, describe their influence on cancer metastasis, and evaluate potential therapeutic interventions for the alleviation of metastatic disease. By triangulating the relationship between immune cells, endothelial cells, and tumor cells, we will gain greater insight into how to impede the metastatic process by focusing on its most vulnerable phases, thereby reducing metastatic spread and cancer-related mortality.

HCRP-1 regulates EGFR-AKT-BIM-mediated anoikis resistance and serves as a prognostic marker in human colon cancer

Hepatocellular carcinoma-related protein-1 (HCRP-1), a subunit of mammalian endosomal sorting complex required for transport-I (ESCRT-I), is frequently downregulated in various kinds of malignant tumors. The role of HCRP-1 in colorectal cancer (CRC) remains unknown. We investigate the clinical value of HCRP-1 and its impact on anoikis in CRC. The negative expression of HCRP-1 was significantly correlated with tumor size (P = 0.033), PT status (P = 0.001), TNM stage (P = 0.039), and histological grade (P = 0.01). Univariate and multivariate analyses revealed that HCRP-1 was an independent prognostic factor for CRC (hazard ratio (HR) = 0.237, P < 0.001 for 5-year overall survival). In the in vitro assay, we found that HCRP-1 depletion resulted in cell anoikis resistance. Knockdown of HCRP-1 suppressed Bcl-2 interacting mediator of cell death (BIM) expression, with phosphorylation of AKT and p-FoxO3a, which was reversed by AKT siRNA or AKT inhibitor. Further analysis showed that loss of HCRP-1 obviously increased the activation of EGFR. Inhibition of EGFR blocked si-HCRP1-mediated phosphorylation of EGFR, AKT, FoxO3a, and BIM expression. Moreover, the in vivo results revealed that loss of HCRP-1 promoted cancer metastasis. Our findings implied that reduced HCRP-1 expression in CRC resulted in anoikis resistance and contributed to CRC metastasis and poor prognosis. These data may help design effective therapy targeting HCRP-1 pathway to control colon cancer growth and metastasis.

The survival outcome of patients with metastatic colorectal cancer based on the site of metastases and the impact of molecular markers and site of primary cancer on metastatic pattern

BACKGROUND

Pattern of spread in patients with metastatic colorectal cancer (mCRC) is variable and may reflect different biology in subsets of patients. This is a retrospective study to explore the outcome of patients with mCRC based on their site of metastasis at diagnosis and to explore the association between tumor characteristics [KRAS/RAS, BRAF, mismatch repair (MMR) status, site of primary] and the site of metastasis.

METHODS

Patients from two Australian databases were divided into six groups based on site of metastasis at time of diagnosis of metastatic disease; lung-only, liver-only, lymph node-only or any patients with brain, bone or peritoneal metastases. Primary endpoint was overall survival (OS) of each cohort compared with the rest of the population. A Mantel-Haenszel chi-squared test used to explore the association between site of metastasis and selected tumor characteristics.

RESULTS

Five thousand nine hundred and sixty-seven patients were included. In a univariate analysis, median OS was significantly higher when metastases were limited to lung or liver and shorter for those with brain, bone or peritoneal metastases (p < .001) in both datasets. BRAF mutation was strongly associated with peritoneal metastases (relative risk = 1.8, p < .001) with lower incidence of lung (RR = 0.3, p = .004) and liver (RR = 0.7, p = .005) limited metastases. Lung-only metastases were more frequent with KRAS/RAS mutation (RR = 1.4, p = .007). Left colon tumors were associated with bone (RR = 1.6, p < .001) and lung-only metastases (RR = 2.3, p = .001) while peritoneal spread was less frequent compared with right colon tumors (RR = 0.6, p < .001). Rectal cancer was associated with brain, bone and lung metastases (RR = 1.7; p = .002, 1.7; p < .001, 2.0; p < .001). Liver-only metastases were less frequent in deficient MMR tumors (RR = 0.7, p = .01).

CONCLUSION

Survival duration with mCRC is related to the site of metastases with lung limited disease showing a more favorable survival outcome compared to other single metastatic site disease. The BRAF mutation and primary rectal cancer were associated with poor prognostic metastatic sites.

SERPINA3 Silencing Inhibits the Migration, Invasion, and Liver Metastasis of Colon Cancer Cells

OBJECTIVE

To investigate the impact of SERPINA3 on the migration, invasion, and liver metastasis of colon cancer cells.

METHODS

Immunohistochemical staining was conducted to determine SERPINA3 expression in the cancer and adjacent normal tissues of 131 patients suffering from colon cancer. In vitro experiment, colon cancer cells with low (HT-29P), intermediate (KM-12C), and high (HT-29LMM, KM-12L4) metastatic potential were obtained to examine SERPINA3 expression levels. Besides, quantitative real-time PCR (qRT-PCR) and Western Blot were performed to detect SERPINA3 expression in HT-29LMM and KM-12L4 cells transfected with SERPINA3 siRNA; Wound-healing and Transwell assays to measure cell migration and invasion, respectively; and ELISA to detect MMP-2 and MMP-9 levels. In vivo experiment, mice with liver metastasis of colon cancer were established to observe the effect of SERPINA3 silencing on liver metastasis. Immunohistochemical assay was applied to evaluate the expressions of Serpina3, Mmp-2, Mmp-9, and proliferating cell nuclear antigen (Pcna) in liver metastasis tissues.

RESULTS

SERPINA3 in colon cancer tissues was higher than in adjacent normal tissues, which was associated with patients' clinicopathological features. Besides, SERPINA3 expression showed a rising trend in low, intermediate, and high metastatic potential colon cancer cells. After KM-12L4 and HT-29LMM cells transfected with SERPINA3 siRNA, the migration and invasive ability of cells, as well as the expression levels of MMP-2 and MMP-9 were all decreased. Moreover, SERPINA3 siRNA could not only reduce live metastasis of mice, but also down-regulate the expression of Mmp-2 and Mmp-9 in liver metastasis tissues.

CONCLUSION

SERPINA3 silencing could inhibit the migration, invasion, and liver metastasis of colon cancer cells.

Deciphering the relative contribution of vascular inflammation and blood rheology in metastatic spreading

Vascular adhesion of circulating tumor cells (CTCs) is a key step in cancer spreading. If inflammation is recognized to favor the formation of vascular "metastatic niches," little is known about the contribution of blood rheology to CTC deposition. Herein, a microfluidic chip, covered by a confluent monolayer of endothelial cells, is used for analyzing the adhesion and rolling of colorectal (HCT-15) and breast (MDA-MB-231) cancer cells under different biophysical conditions. These include the analysis of cell transport in a physiological solution and whole blood over a healthy and a TNF-α inflamed endothelium with a flow rate of 50 and 100 nl/min. Upon stimulation of the endothelial monolayer with TNF-α (25 ng/ml), CTC adhesion increases from 2 to 4 times whilst cell rolling velocity only slightly reduces. Notably, whole blood also enhances cancer cell deposition from 2 to 3 times, but only on the unstimulated vasculature. For all tested conditions, no statistically significant difference is observed between the two cancer cell types. Finally, a computational model for CTC transport demonstrates that a rigid cell approximation reasonably predicts rolling velocities while cell deformability is needed to model adhesion. These results would suggest that, within microvascular networks, blood rheology and inflammation contribute similarly to CTC deposition, thereby facilitating the formation of metastatic niches along the entire network, including the healthy endothelium. In microfluidic-based assays, neglecting blood rheology would significantly underestimate the metastatic potential of cancer cells.

Isolated pancreatic metastases from renal cell carcinoma: an outcome of a special metastatic pathway or of specific tumor cell selection?

Isolated pancreatic metastases (isPM) are a rare metastasizing pattern in the natural history of renal cell cancer. Their clinical hallmark is that they are confined to a single organ, the pancreas, while all other organs are unaffected for a long time. Almost all workers in the field suggested that mechanical tumor cell propagation to the pancreas may be the mechanism underlying this metastasizing pattern. In 2006 our group, by contrast, proposed an alternative mechanism, i.e. a special affinity of the tumor cells for the pancreas. In the present study an attempt was made to shed more light on the settlement of isPM by reviewing recent literature data. 666 observations of isPM reported in the literature were reviewed. The analyses showed that local lymphatic spread does not play a major role because the lymphatic system is, in general, rarely involved in isPM. This also applies to a local venous spread, because the site of pancreatic metastases is independent of the side affected by the primary renal cancer. But the results are compatible with a systemic metastatic pathway. That metastases in other organs, which would be expected given a systemic spread, are absent can plausibly be explained by a seed and soil mechanism: only the pancreas offers the tumor cell emboli an environment which is conducive to the growth of clinically manifest metastases, while settlement of metastatic tumor cells is prevented in all other organs.

Fluid shear stress and tumor metastasis

The tumor microenvironment (TME) is a key factor regulating tumor cell invasion and metastasis. The effects of biochemical factors such as stromal cells, immune cells, and cytokines have been previously investigated. Owing to restrictions by the natural barrier between physical and biochemical disciplines, the role of physical factors in tumorigenesis is unclear. However, with the emergence of interdisciplinary mechanobiology and continuous advancements therein in the past 30 years, studies on the effect of physical properties such as hardness or shear stress on tumorigenesis and tumor progression are constantly renewing our understanding of mechanotransduction mechanisms. Shear stress, induced by liquid flow, is known to actively participate in proliferation, apoptosis, invasion, and metastasis of tumor cells. The present review discusses the progress and achievements in studies on tumor fluid microenvironment in recent years, especially fluid shear stress, on tumor metastasis, and presents directions for future study.

Tumor Metastasis in the Microcirculation

Tumor cell metastasis through blood circulation is a complex process and is one of the great challenges in cancer research as metastatic spread is responsible for ∼90% of cancer-related mortality. Tumor cell intravasation into, arrest and adhesion at, and extravasation from the microvessel walls are critical steps in metastatic spread. Understanding these steps may lead to new therapeutic concepts for tumor metastasis. Vascular endothelium forming the microvessel wall and the glycocalyx layer at its surface are the principal barriers to and regulators of the material exchange between circulating blood and body tissues. The cleft between adjacent endothelial cells is the principal pathway for water and solute transport through the microvessel wall in health. Recently, this cleft has been found to be the location for tumor cell adhesion and extravasation. The blood-flow-induced hydrodynamic factors such as shear rates and stresses, shear rate and stress gradients, as well as vorticities, especially at the branches and turns of microvasculatures, also play important roles in tumor cell arrest and adhesion. This chapter therefore reports the current advances from in vivo animal studies and in vitro culture cell studies to demonstrate how the endothelial integrity or microvascular permeability, hydrodynamic factors, microvascular geometry, cell adhesion molecules, and surrounding extracellular matrix affect critical steps of tumor metastasis in the microcirculation.

Evaluation of predictive factors of vertebral compression fracture after conventional palliative radiotherapy for spinal metastasis from colorectal cancer

OBJECTIVE Delayed consequences of spinal radiotherapy (RT), including vertebral compression fracture (VCF), are critical complications. However, the predisposing factors that contribute to VCF after conventional RT are unclear. The aim of this study was to assess the incidence of VCF and to determine the predictors of VCF following conventional spinal RT specific to colorectal cancer (CRC). METHODS The authors retrospectively reviewed 237 spinal segments (147 metastatic and 90 nonmetastatic) in 53 patients with CRC who underwent RT with a median total dose of 30 Gy in 10 fractions between January 2007 and December 2014. The primary end point was the development of a VCF following RT, either de novo VCF or the progression of a baseline VCF. VCFs were assessed using the spinal instability neoplastic score (SINS) criteria. RESULTS Among all 237 spinal segments, 22 VCFs (9.3%) were observed following RT, including 13 de novo and 9 progressive fractures, and the median time to VCF was 4 months. All VCFs developed in metastatic spines. Among 147 metastatic spinal segments, 22 fractures were observed, with a 12-month cumulative incidence of VCF of 14.8%. Results of multivariable analysis indicated sex (p = 0.023) and SINS class II/III (p < 0.001) as risk factors related to development of a VCF in metastatic spinal segments. Among the SINS criteria, a lytic tumor and the presence of a baseline VCF were identified as predictors of VCF in metastatic spinal segments. CONCLUSIONS In osteolytic or mixed lesions that were predominant in spinal metastases of CRC, the incidence of VCF was not negligible, even in patients treated with conventional spinal RT. This was especially evident in patients with spinal metastases with a SINS score ≥ 7. Presence of a baseline VCF after spinal RT is a predictor of VCF development and should be observed carefully.

Retrospective study of predictors of bone metastasis in colorectal cancer patients

BACKGROUND

We explored risk factors for bone metastasis (BMs) in colorectal cancer (CRC) to improve in early diagnosis and follow-up and to reduce bone metastasis.

METHODS

With a retrospective analysis of 2066 patients with CRC treated in our institution from January 2006 to January 2015, we assessed high-risk variables associated with bone metastasis using univariate and multivariate analyses.

RESULTS

Of those subjects studied, 102 patients developed BMs, including 62 of 1014 the rectal cancer patients and 40 of the 1052 colon cancer patients. Lung metastases were accounting for 59.8% of the BMs (χ2 = 17.7, p<0.01) and hepatic metastases were accounting for 34.3% of BMs (χ2 = 3.06,p >0.05). BMs were diagnosed more rapidly in the presence of lung metastases(6.9 months versus 11.6 months for liver metastases). Univariate analysis revealed that BMs were associated with primary tumor location (p < 0.001), lung metastases (p < 0.001), initial stage (p = 0.001), radiotherapy (p < 0.001) and serum carcinoembryonic antigen (CEA) (p=0.001). Multivariate analysis revealed that primary tumor location (rectum), lung metastases, and serum CEA (>5 μg/L) were statistically significant (p <0.05).

CONCLUSIONS

BMs in rectal cancer occur more frequently than in colon cancer. Lung metastases predicted potential progression to bone in CRCs more than liver metastases. Primary rectal locations, lung metastases and serum CEA were independent risk factors for BMs in CRC. Thus, patients should receive early bones scanning when presenting with CRC.

The role of vitamin D in hepatic metastases from colorectal cancer

Colorectal cancer (CRC) represents a significant health burden worldwide, comprising approximately 10% of annual cancer cases globally. Hepatic metastases are the most common site of CRC metastasis, and are the leading cause of death in CRC patients. There is strong epidemiologic evidence for an inverse association between vitamin D status and risk of CRC; however, the role of vitamin D in the natural history of liver metastases has not yet been investigated. Several researchers have proposed hallmarks of metastases; crucially, metastases can be blocked by interrupting just one rate-limiting step. Vitamin D status has been implicated in each proposed hallmark of metastasis. The aim of this review is to examine the potential role for vitamin D in reducing the development of hepatic metastases from CRC and outline the candidate mechanisms by which vitamin D may mediate these effects. The results of ongoing randomised intervention trials are eagerly awaited to determine whether addressing vitamin D insufficiency in CRC patients could reduce the occurrence of liver metastases, and the consequent morbidity and mortality.

A circulating tumor cell cluster-based model for tumor metastasis (Hypothesis)

Metastasis is the major cause of mortality in patients with malignancies; however, the mechanisms of tumor cell dissemination and metastasis formation are obscure. Circulating tumor cells (CTCs) are believed to be a critical step for distant metastasis and are associated with a poor patient prognosis. The precise processes of metastasis formation from CTCs are vague. In the present study, we hypothesize that two CTC cluster-based mechanisms of tumor cell inoculation in ectopic organs may be viable: i) Formation of a micro-cancer embolus due to interception of CTC clusters by small vessels; and ii) formation of micrometastasis in an extravasation-dependent or -independent manner. Pathological evidence of micro-cancer emboli is critical for the verifications of this hypothesis. If proved true, this hypothesis will provide a novel perspective for cancer metastasis and has valuable clinical implications.

Colon cancer metastasis to the sternum: palliative treatment with radiofrequency ablation and cement injection

Colon cancer metastasis to bone is extremely rare and has devastating consequences on patients' quality of life. Furthermore, radiofrequency ablation in conjunction with cementoplasty to nonweight bearing, flat bones has not been widely reported as palliative treatment for pain as a result of bone metastasis. Here, we present a case of a 47-year-old man who developed a sternal metastasis from an invasive adenocarcinoma of the colon originally diagnosed several years prior. The pain from the metastasis was originally treated with external beam radiation therapy, but after 6 weeks of continuous pain, it was retreated using radiofrequency ablation in conjunction with cementoplasty.

Selective Harvesting of Marginating-hepatic Leukocytes

Marginating-hepatic (MH) leukocytes (leukocytes adhering to the sinusoids of the liver), were shown to exhibit unique composition and characteristics compared to leukocytes of other immune compartments. Specifically, evidence suggests a distinct pro- and anti-inflammatory profile of the MH-leukocyte population and higher cytotoxicity of liver-specific NK cells (namely, pit cells) compared to circulating or splenic immunocytes in both mice and rats. The method presented herein enables selective harvesting of MH leukocytes by forced perfusion of the liver in mice and rats. In contrast to other methods used to extract liver-leukocytes, including tissue grinding and biological degradation, this method exclusively yields leukocytes from the liver sinusoids, uncontaminated by cells from other liver compartments. In addition, the perfusion technique better preserves the integrity and the physiological milieu of MH leukocytes, sparing known physiological responses to tissue processing. As many circulating malignant cells and infected cells are detained while passing through the liver sinusoids, physically interacting with endothelial cells and resident leukocytes, the unique MH leukocyte population is strategically located to interact, identify, and react towards aberrant circulating cells. Thus, selective harvesting of MH-leukocytes and their study under various conditions may advance our understanding of the biological and clinical significance of MH leukocytes, specifically with respect to circulating aberrant cells and liver-related diseases and cancer metastases.

Cell adhesion during bullet motion in capillaries

A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis.

Quantification of cancer cell extravasation in vivo

Cancer cell 'invasiveness' is one of the main driving forces in cancer metastasis, and assays that quantify this key attribute of cancer cells are crucial in cancer metastasis research. The research goal of many laboratories is to elucidate the signaling pathways and effectors that are responsible for cancer cell invasion, but many of these experiments rely on in vitro methods that do not specifically simulate individual steps of the metastatic cascade. Cancer cell extravasation is arguably the most important example of invasion in the metastatic cascade, whereby a single cancer cell undergoes transendothelial migration, forming invasive processes known as invadopodia to mediate translocation of the tumor cell from the vessel lumen into tissue in vivo. We have developed a rapid, reproducible and economical technique to evaluate cancer cell invasiveness by quantifying in vivo rates of cancer cell extravasation in the chorioallantoic membrane (CAM) of chicken embryos. This technique enables the investigator to perform well-powered loss-of-function studies of cancer cell extravasation within 24 h, and it can be used to identify and validate drugs with potential antimetastatic effects that specifically target cancer cell extravasation. A key advantage of this technique over similar assays is that intravascular cancer cells within the capillary bed of the CAM are clearly distinct from extravasated cells, which makes cancer cell extravasation easy to detect. An intermediate level of experience in injections of the chorioallantoic membrane of avian embryos and cell culture techniques is required to carry out the protocol.

Metastatic colorectal cancer presenting with bone marrow metastasis: a case series and review of literature

With advances in treatment, patients with metastatic colorectal cancer (CRC) are now living longer with an apparent increase in the incidence of bone and bone marrow metastases (BMM). Common sites of metastatic disease from CRC include the liver and lungs with bone metastasis rarely occurring in the absence of visceral metastatic disease. We report a series of three patients presenting with isolated bone and BMM leading to a diagnosis of primary CRC. We have reviewed the literature regarding diagnosis, potential mechanisms leading to the development of osseous metastasis and outcome. A high level of clinical suspicion and in-depth understanding of the natural history of these rare metastases may guide future management and treatment decisions.

Significance of TNF-α and the Adhesion Molecules: L-Selectin and VCAM-1 in Papillary Thyroid Carcinoma

Circulating levels of TNF-α and the adhesion molecules L-Selectin and VCAM-1 as well as their expression in the primary tumors of patients with benign thyroid diseases and papillary thyroid carcinoma (PTC) have been determined in this study. The serum levels of TNF-α, L-Selectin, and VCAM-1 were significantly higher in patients with both benign thyroid diseases and PTC as compared to the healthy individuals. However, the levels of only TNF-α and L-Selectin, and not VCAM-1, were significantly higher in patients with PTC in comparison to those observed in patients with benign thyroid diseases. Further the expression of TNF-α and L-Selectin was also significantly higher in the primary tumors of PTC patients, relative to the benign thyroid diseases. The expression of L-Selectin and VCAM-1 significantly correlated with aggressive tumor behavior. In PTC patients, the circulating TNF-α levels significantly positively correlated with the levels of L-Selectin, while TNF-α immunoreactivity was significantly associated with VCAM-1 expression. Serum TNF-α was found to be a significant prognosticator for OS in PTC patients. Overall the results signify that the interaction between TNF-α and the adhesion molecules may have a role in thyroid carcinogenesis and understanding this complexity may offer potential therapeutic targets for better management of thyroid cancer.

Targeting tumor metastases: Drug delivery mechanisms and technologies

Primary sites of tumor are the focal triggers of cancers, yet it is the subsequent metastasis events that cause the majority of the morbidity and mortality. Metastatic tumor cells exhibit a phenotype that differs from that of the parent cells, as they represent a resistant, invasive subpopulation of the original tumor, may have acquired additional genetic or epigenetic alterations under exposure to prior chemotherapeutic or radiotherapeutic treatments, and reside in a microenvironment differing from that of its origin. This combination of resistant phenotype and distal location make tracking and treating metastases particularly challenging. In this review, we highlight some of the unique biological traits of metastasis, which in turn, inspire emerging strategies for targeted imaging of metastasized tumors and metastasis-directed delivery of therapeutics.

Colorectal cancer: Metastases to a single organ

Colorectal cancer (CRC) is a common malignancy worldwide. In CRC patients, metastases are the main cause of cancer-related mortality. In a group of metastatic CRC patients, the metastases are limited to a single site (solitary organ); the liver and lungs are the most commonly involved sites. When metastatic disease is limited to the liver and/or lungs, the resectability of the metastatic lesions will dictate the management approach and the outcome. Less commonly, the site of solitary organ CRC metastasis is the peritoneum. In these patients, cytoreduction followed by hyperthermic intraperitoneal chemotherapy may improve the outcome. Rarely, CRC involves other organs, such as the brain, bone, adrenals and spleen, as the only site of metastatic disease. There are limited data to guide clinical practice in these cases. Here, we have reviewed the disease characteristics, management approaches and prognosis based on the metastatic disease site in patients with CRC with metastases to a single organ.

RAS mutations affect pattern of metastatic spread and increase propensity for brain metastasis in colorectal cancer

BACKGROUND

RAS and PIK3CA mutations in metastatic colorectal cancer (mCRC) have been associated with worse survival. We sought to evaluate the impact of RAS and PIK3CA mutations on cumulative incidence of metastasis to potentially curable sites of liver and lung and other sites such as bone and brain.

METHODS

We performed a computerized search of the electronic medical record of our institution for mCRC cases genotyped for RAS or PIK3CA mutations from 2008 to 2012. Cases were reviewed for patient characteristics, survival, and site-specific metastasis.

RESULTS

Among the 918 patients identified, 477 cases were RAS wild type, and 441 cases had a RAS mutation (394 at KRAS exon 2, 29 at KRAS exon 3 or 4, and 18 in NRAS). RAS mutation was significantly associated with shorter median overall survival (OS) and on multivariate analysis independently predicted worse OS (HR, 1.6; P < .01). RAS mutant mCRC exhibited a significantly higher cumulative incidence of lung, bone, and brain metastasis and on multivariate analysis was an independent predictor of involvement of these sites (HR, 1.5, 1.6, and 3.7, respectively). PIK3CA mutations occurred in 10% of the 786 cases genotyped, did not predict for worse survival, and did not exhibit a site-specific pattern of metastatic spread.

CONCLUSIONS

The metastatic potential of CRC varies with the presence of RAS mutation. RAS mutation is associated with worse OS and increased incidence of lung, bone, and brain metastasis. An understanding of this site-specific pattern of spread may help to inform physicians' assessment of symptoms in patients with mCRC.

Selenoglycoproteins attenuate adhesion of tumor cells to the brain microvascular endothelium via a process involving NF-κB activation

Selenium-containing compounds and selenized yeast have anticancer properties. In order to address possible mechanisms involved in these effects, selenoglycoproteins (SGPs) were extracted from selenium-enriched yeast at pH 4.0 and 6.5 (the fractions are called SGP40 and SGP65, respectively), followed by evaluation of their impact on the interactions of lung and breast tumor cells with human brain microvascular endothelial cells (HBMECs). Extracted SGPs, especially SGP40, significantly inhibited adhesion of tumor cells to HBMECs and their transendothelial migration. Because the active components of SGPs are unknown, small selenium-containing compounds [leucyl-valyl-selenomethionyl-arginine (LVSe-MR) and methylselenoadenosine (M-Se-A)], which are normally present in selenized yeast, were introduced as additional treatment groups. Treatment of HBMECs with SGP40, LVSe-MR and M-Se-A induced changes in gene signatures, which suggested a central involvement of nuclear factor (NF)-κB-dependent pathway. These observations were confirmed in the subsequent analysis of NF-κB DNA binding activity, quantitative measurements of the expression of selected genes and proteins, and tumor cell adhesion assay with a specific NF-κB inhibitor as the additional treatment factor. These findings indicate that specific organic selenium-containing compounds have the ability to inhibit tumor cell adhesion to brain endothelial cells via down-regulation of NF-κB. SGPs appear to be more effective than small selenium-containing compounds, suggesting the role of not only selenium but also the glycoprotein component in the observed protective impact.

Kupffer cells decrease metastasis of colon cancer cells to the liver in the early stage

Although Kupffer cells (KCs) play an important role in the liver's immune response, their role in colon cancer metastasis to the liver is unclear. We here analyzed the relationship between KCs and tumor cells (TCs) in colon cancer metastasis to the liver. Fischer 344 (F344) rats were divided into control group (KC+ group) and KC elimination group (KC‑ group), in which KC elimination was induced by Cl2MDP liposome injection. RCN‑H4 colon cancer cells were injected into the rats of both groups, and the relationship between the two types of cells was observed by intravital microscopy (IVM) for 6 h. Moreover, to investigate the effect of KCs on liver metastasis formation, KCs were eliminated at different time points before and after the TC injection. The number of metastatic nodules 2 weeks after the injection was evaluated. In the KC‑ group, IVM revealed that the number of adherent TCs had increased 1.5‑fold at 6 h after the TC injection as compared with in the KC+ group. Moreover, in the KC+ group, 74% of the TCs adhered to the KCs, and KC activation and KC phagocytosis of the TCs were observed. Two weeks after the injection, the number of metastatic nodules was significantly increased in rats in which the KCs had been eliminated before the injection, but not in rats in which the KCs had been eliminated after the injection. KC activation and KC phagocytosis of TCs decreased colon cancer cell metastasis to the liver.

KRAS mutation influences recurrence patterns in patients undergoing hepatic resection of colorectal metastases

BACKGROUND

The validity of the KRAS mutation as a predictor of recurrence-free survival (RFS) or overall survival (OS) is unclear. The current study investigated whether the presence of the KRAS mutation decreased RFS or OS in patients with colorectal cancer who underwent liver resection.

METHODS

Patients with resected colorectal liver metastases who received adjuvant hepatic arterial infusion plus systemic therapy and for whom KRAS data was available were evaluated. Correlation between KRAS and clinical factors was done using the Fisher exact test. Kaplan-Meier methods were used to estimate the median RFS and OS.

RESULTS

A total of 169 patients were evaluated, 118 of whom had KRAS wild-type (WT) and 51 had KRAS mutated (MUT) tumors. The 3-year RFS rate was 46% for patients with KRAS WT (95% confidence interval [95% CI], 35%-56%) and 30% (95% CI, 16%-44%) for patients with KRAS MUT (P =.005). The 3-year OS rate was 95% (95% CI, 87%-98%) and 81% (95% CI, 62%-95%), respectively, for patients with KRAS WT and KRAS MUT (P =.07). On multivariate analysis, KRAS remained a significant predictor of RFS (hazard ratio, 1.9). The 3-year cumulative recurrence rate by site of metastases was as follows: 2% versus 13.4% for bone (P≤.01), 2% versus 14.5% for brain (P =.05), 33.2% versus 58% for lung (P≤.01), and 30% versus 47% for liver (P =.10) in patients with KRAS WT versus KRAS MUT.

CONCLUSIONS

In the current study, among patients with resected colorectal liver metastases who were treated with adjuvant hepatic arterial infusion plus systemic therapy, patients with KRAS MUT were found to have a significantly worse 3-year RFS (30%) compared with KRAS WT (46%) p=.005. The cumulative incidence of bone, brain, and lung metastases was significantly higher for patients with KRAS MUT compared with those with KRAS WT.

Metastasis review: from bench to bedside

Cancer is the final result of uninhibited cell growth that involves an enormous group of associated diseases. One major aspect of cancer is when cells attack adjacent components of the body and spread to other organs, named metastasis, which is the major cause of cancer-related mortality. In developing this process, metastatic cells must successfully negotiate a series of complex steps, including dissociation, invasion, intravasation, extravasation, and dormancy regulated by various signaling pathways. In this review, we will focus on the recent studies and collect a comprehensive encyclopedia in molecular basis of metastasis, and then we will discuss some new potential therapeutics which target the metastasis pathways. Understanding the new aspects on molecular mechanisms and signaling pathways controlling tumor cell metastasis is critical for the development of therapeutic strategies for cancer patients that would be valuable for researchers in both fields of molecular and clinical oncology.

Galectin-3 expressed on different lung compartments promotes organ specific metastasis by facilitating arrest, extravasation and organ colonization via high affinity ligands on melanoma cells

Interactions between molecules on the surface of tumor cells and those on the target organ endothelium play an important role in their arrest in an organ. Galectin-3 on the lung endothelium and high affinity ligands poly-N-acetyllactosamine (polyLacNAc) on N-oligosaccharides on melanoma cells facilitate such interactions. However, to extravasate and colonize an organ the cells must stabilize these interactions by spreading to retract endothelium, degrade exposed basement membrane (BM) and move into parenchyma and proliferate. Here, we show that galectin-3 is expressed on all the major compartments of the lungs and participates in not just promoting adhesion but also in spreading. We for the first time demonstrate that both soluble and immobilized galectin-3 induce secretion of MMP-9 required to breach vascular BM. Further, we show that immobilized galectin-3 is used as traction for the movement of cells. Downregulation of galactosyltransferases-I and -V resulted in significant loss in expression of polyLacNAc and thus reduced binding of galectin-3. This was accompanied with a loss in adhesion, spreading, MMP-9 secretion and motility of the cells on galectin-3 and thus their metastasis to lungs. Metastasis could also be inhibited by blocking surface polyLacNAc by pre-incubating cells with truncated galectin-3 (which lacked oligomerization domain) or by feeding mice with modified citrus pectin in drinking water. Overall, these results unequivocally show that polyLacNAc on melanoma cells and galectin-3 on the lungs play a critical role in arrest and extravasation of cells in the lungs and strategies that target these interactions inhibit lung metastasis.