The role of EMT and MET in cancer dissemination

Atg7 inhibits Warburg effect by suppressing PKM2 phosphorylation resulting reduced epithelial-mesenchymal transition

Metabolic reprogramming is a distinct hallmark in tumorigenesis. Autophagy can rewire cell metabolism by regulating intracellular homeostasis. Warburg effect is a specific energy metabolic process that allows tumor cells to metabolize glucose via glycolysis into lactate even in the presence of oxygen. Although both autophagy and Warburg effect are involved in the stress response to energy crisis in tumor cells, their molecular relationship has remained largely elusive. We found that Atg7, a key molecule involved in autophagy, inhibits the Warburg effect. Mechanistically, Atg7 binds PKM2 and prevents its Tyr-105 phosphorylation by FGFR1. Furthermore, the hyperphosphorylation of PKM2 and its induced Warburg effect due to Atg7 deficiency promote epithelial-mesenchymal transition (EMT). Conversely, overexpression of Atg7 inhibits PKM2 phosphorylation and the Warburg effect, thereby inhibiting EMT of tumor cells. Our work reveals a molecular link between Atg7 and the Warburg effect, which may provide insight into novel strategies for cancer treatment.

Anti‑metastatic effects of Aidi on human esophageal squamous cell carcinoma by inhibiting epithelial‑mesenchymal transition and angiogenesis

Aidi injection, a proprietary Chinese medicine, has been widely used for the treatment of cancer. However, its effects and potential mechanism in esophageal squamous cell carcinoma (ESCC) have not yet been characterized. The aim of the present study was to identify the mechanism underlying the anti-metastatic effects of treatment with Aidi. To test the effects and mechanism, EC9706 and KYSE70 cells were selected for in vitro experiments. In vivo, the anti-metastatic effects of Aidi injection on a nude mouse peritoneal metastasis model were examined, and the mechanisms were assessed with immunohistochemical staining. A cell proliferation assay demonstrated that treatment with more than 3 mg/ml Aidi for 24 or 48 h significantly inhibited the proliferation of EC9706 (P<0.01) and KYSE70 cells (P<0.05, P<0.01). Subsequent experiments assessed cell migration, invasion and vasculogenic mimicry (VM) formation, with 5-fluorouracil serving as a positive control. It was observed that treatment with Aidi inhibited cell migration, invasion and VM formation. Furthermore, it was identified that treatment with Aidi inhibited epithelial-mesenchymal transition (EMT) signaling and the expression of vascular endothelial growth factor A (VEGF-A) in EC9706 and KYSE70 cells, using western blotting. In the in vivo experiments, Aidi injection effectively suppressed tumor metastasis in the mouse tumor model. Additionally, the expression of vimentin and vascular endothelial growth factor was decreased, and the expression of cadherin-1 was increased in the tumor tissue. The present results suggested that treatment with Aidi may inhibit tumor metastasis in ESCC through the inhibition of EMT signaling and angiogenesis.

Exosome-mediated peritoneal dissemination in gastric cancer and its clinical applications

The prognosis of patients with peritoneal dissemination from gastric cancer is poor, and the underlying molecular mechanism remains unclear. Exosomes, as macromolecular phospholipid bilayer vesicles comprising of proteins, nucleic acids and lipids, serve as mediators of cell-cell communication. Gastric cancer tumor-derived exosomes may be involved in the pathological process of peritoneal dissemination by mediating crosstalk between cancer cells and mesothelial cells, to result in the induction of enhanced tumor growth, migratory, adhesive and invasive abilities, peritoneal fibrosis and apoptosis, mesothelial-to-mesenchymal transition, angiogenesis and chemoresistance. The present review focuses on previous studies addressing the exosome-dependent molecular transfer in peritoneal dissemination in gastric cancer and the potential clinical applications.

The role of exosomal non-coding RNAs in cancer metastasis

An increasing number of studies has confirmed that many cells can secrete vesicles or exosomes in eukaryotes, which contain important nucleic acids, proteins and lipids and play important roles in cell communication and tumor metastasis. This paper summarizes the comprehensive function of exosomal non-coding RNAs. Although some studies have shown that exosomes mediate tumor signal transduction, the functional mechanism of the tumor metastasis remains to be elucidated. In this paper, we reviewed the role of exosomal non-coding RNAs in mediating cancer metastasis in the tumor microenvironment to provide new ideas for the study of tumor pathophysiology.

Long non-coding RNA lncTCF7 predicts poor prognosis and promotes tumor metastasis in osteosarcoma

The 5-year survival rate of patients with metastatic osteosarcoma remains poor. Therefore, the molecular mechanisms underlying metastasis of osteosarcoma need to be investigated. Long non-coding RNA lncTCF7 promotes tumor metastasis in liver and lung cancers; however, its role in osteosarcoma remains unclear. In this study, we found that lncTCF7 expression was significantly higher in osteosarcoma tissues than that in adjacent normal osteosarcoma tissues and upregulated lncTCF7 expression was significantly correlated with tumor metastasis, higher TNM grade and lower survival rate. Additionally, we observed that lncTCF7 silencing significantly inhibited the migration and invasion of osteosarcoma cells, but showed no effects on the proliferation and apoptosis of these cells. lncTCF7 silencing markedly increased the expression of E-cadherin and decreased the expressions of N-cadherin, vimentin, matrix metalloproteinase-2 (MMP-2), and MMP-9, which exerted a potentiating effect on EMT. The result was suggested that lncTCF7 silencing inhibited tumor metastasis in osteosarcoma by possibly inhibiting EMT process. In conclusion, these observations indicated the potential of lncTCF7 as a biomarker of poor prognosis and promising target for treating osteosarcoma.

Role of exosomes in hepatocellular carcinoma cell mobility alteration

Exosomes have gained increased research focus due to their key roles as messengers. The components of exosomes include proteins and RNAs that may be horizontally transferred between adjacent or distant cells. Hepatocellular carcinoma (HCC) is among the most malignant types of cancer worldwide, with exosomes implicated to play a crucial role in its regulation; however, the possible function of exosomes in modulating the motile ability of tumor cells and key molecules in HCC remain largely unknown. To investigate the regulatory effect of exosomes on the motile ability of HCC cells, exosomes from the culture medium of different HCC origins (high metastatic MHCC97-H and low metastatic MHCC97-L cells) were isolated for in vitro migration and invasion assays. The results indicated that the motile ability of MHCC97-L cells was significantly increased by pretreatment with MHCC97-H-derived exosomes when compared with MHCC97-L-exosome pretreatment (P<0.05). To further characterize the function of exosomes at the molecular level, protein profiling of exosomes from different cell origins was performed, which identified 129 proteins. Among these, adenylyl cyclase-associated protein 1, a protein implicated in HCC metastasis, was significantly enriched in exosomes from cells with high motile ability (P<0.05). The results of the present study validated the regulatory effect of exosomes on the motile ability of HCC cells. Furthermore, systematic analysis of the protein profiles of exosomes from different origins identified potential factors correlated with HCC metastasis, which may provide a basis for future functional analysis of exosomes regarding their involvement in cancer metastasis and recurrence.

Inversed Expression Patterns of S100A4 and E-Cadherin in Cervical Cancers: Implication in Epithelial-Mesenchymal Transition

Cervical cancer/CC is the third commonest female malignancy worldwide. The aggressive growth and distal metastases are the leading causes of CC mortality, which is largely due to epithelial-mesenchymal transition/EMT. Fibroblast specific protein S100A4 promotes cancer metastasis and epithelial type cadherin/E-cadherin play pivotal roles in cell-cell and cell-extracellular matrix interaction. Therefore, the expression patterns of S100A4 and E-cadherin reflect statuses of EMT of carcinoma cells. However, S100A4 expression and its relevance with E-cadherin and HPV16 infection in cervical cancers remain unknown. This study aims to address the above issues using cervical cancer specimens. Immunohistochemistry reveals that the levels of mesenchymal marker S100A4 is upregulated (>++) in cervical adenocarcinomas/CACs (12/16; 75%) and squamous cell carcinomas/CSCCs (23/28; 82%) than that in noncancerous glandular epithelia/GE (0/12; 0%) and squamous epithelia/SE (0/12; 0%). Epithelial marker membranous E-cadherin is remarkably reduced on the surface of CAC and CSCC cells (P = 0.00; P = 0.00), especially those showing poorly differentiated phenotypes (P < 0.05) in comparison with their noncancerous counterparts. Correlative analyses revealed an inverse relationship between S100A4 and E-cadherin expression among the cervical cancer samples (P = 0.01, r = -0.38). S100A4 expression level in HPV16-infected group is higher than that in HPV16-free group (P = 0.02). These results suggest the close correlation of S100A4 upregulation with cervical cancer formation and HPV16 infection and E-cadherin reduction with the grades of CC dedifferentiation. The concurrent gain of S100A4 and loss of membrane E-cadherin suggest EMT tendency of CC cells and can be regarded as an unfavorable prognostic parameter of CC patients. Anat Rec, 300:2184-2191, 2017. © 2017 Wiley Periodicals, Inc.

Metabolic reprogramming underlies metastatic potential in an obesity-responsive murine model of metastatic triple negative breast cancer

The vast majority of cancer-related deaths are due to metastatic disease, whereby primary tumor cells disseminate and colonize distal sites within the body. Triple negative breast cancer typically displays aberrant Wnt signaling, lacks effective targeted therapies, and compared with other breast cancer subtypes, is more likely to recur and metastasize. We developed a Wnt-driven lung metastasis model of triple negative breast cancer (metM-Wnt^lung) through serial passaging of our previously described, nonmetastatic, claudin-low M-Wnt cell line. metM-Wnt^lung cells displayed characteristics of epithelial-to-mesenchymal transition (e.g., increased invasiveness) with some re-epithealization (e.g., increased adhesion, tight colony formation, increased E-cadherin expression, and decreased Vimentin and Fibronectin expression). When orthotopically transplanted into syngeneic mice, metM-Wnt^lung cells readily formed tumors and metastasized in vivo, and tumor growth and metastasis were enhanced in obese mice compared with non-obese mice. Gene expression analysis revealed several genes and pathways altered in metM-Wnt^lung cells compared with M-Wnt cells, including multiple genes associated with epithelial-to-mesenchymal transition, energy metabolism and inflammation. Moreover, obesity caused significant transcriptomic changes, especially in metabolic pathways. Metabolic flux analyses showed greater metabolic plasticity, with heightened mitochondrial and glycolytic energetics in metM-Wnt^lung cells relative to M-Wnt cells. Similar metabolic profiles were found in a second triple negative breast cancer progression series, M6 and M6C cells. These findings suggest that metabolic reprogramming is a feature of metastatic potential in triple negative breast cancer. Thus, targeting metastases-associated metabolic perturbations may represent a novel strategy for reducing the burden of metastatic triple negative breast cancer, particularly in obese women.

Metabolic changes contribute to the metastatic potential of triple negative breast cancer (TNBC), a mouse study shows. Stephen Hursting and colleagues from the University of North Carolina at Chapel Hill, USA, established metastatic mouse TNBC cells driven by Wnt-1, a signaling protein that’s highly active in this aggressive subtype of breast cancer. In a lab dish, these cells showed signs of increased invasiveness; and when transplanted into mice, the cells readily formed tumors that metastasized to the lungs. Obese mice experienced more aggressive tumor growth and spread than normal-weight animals. Gene expression analyses revealed that TNBC cells with metastatic potential have an energetic leg-up over their non-metastatic counterparts in the face of obesity-induced metabolic changes, suggesting that targeting metabolic perturbations could help reduce the burden of metastatic TNBC, particularly for obese women.

Exosomes in diagnosis and therapy of prostate cancer

Exosomes are small vesicular bodies released by a variety of cells. Exosomes contain miRNAs, mRNAs and proteins with the potential to regulate signaling pathways in recipient cells. Exosomes deliver nucleic acids and proteins to mediate the communication between cancer cells and stroma cells. In this review, we summarize recent progress in our understanding of the role of exosomes in prostate cancer. The tumorigenesis, metastasis and drug resistance of prostate cancer are associated with the cargos of exosomes such as miRNAs, lncRNAs and proteins. In addition, prostate cancer cells modulate surrounding stromal cells via the exosomes. Affected stromal cells employ the exosomes to modulate microenvironment and promote tumor growth and metastasis. Exosomes derived from prostate cancer cells contribute to cancer chemoresistance. The lipid bilayer membrane of the exosomes makes them promising carriers of drugs and other therapeutic molecules targeting prostate cancer. Furthermore, exosomes can be detected and isolated from various body fluids for the diagnosis of prostate cancer.

Epithelial-to-mesenchymal transition, circulating tumor cells and cancer metastasis: Mechanisms and clinical applications

Epithelial-to-mesenchymal transition (EMT) endows epithelial cells with enhanced motility and invasiveness, allowing them to participate in many physiological and pathological processes. Epithelial-to-mesenchymal transition contributes to the generation of circulating tumor cells (CTCs) in epithelial cancers because it increases tumor cell invasiveness, promotes tumor cell intravasation and ensures tumor cell survival in the peripheral system. Although the contribution of epithelial-to-mesenchymal transition to tumor cell invasiveness has been confirmed, the role epithelial-to-mesenchymal transition plays in metastasis remains debated. As a favorable material for a “liquid biopsy”, circulating tumor cells have been shown to have promising values in the clinical management of tumors. Furthermore, an increasing number of studies have begun to explore the value of CTC-related biomarkers, and some studies have found that the expression of EMT and stemness markers in circulating tumor cells, in addition to CTC detection, can provide more information on tumor diagnosis, treatment, prognosis and research.

MiR-520b as a novel molecular target for suppressing stemness phenotype of head-neck cancer by inhibiting CD44

Cancer stem cells preferentially acquire the specific characteristics of stress tolerance and high mobility, allowing them to progress to a therapy-refractive state. To identify a critical molecule to regulate cancer stemness is indispensable to erratically cure cancer. In this study, we identified miR-520b as a novel molecular target to suppress head-neck cancer (HNC) with stemness phenotype. MiR-520b inhibited cellular migration and invasion via the mechanism of epithelial-mesenchymal transition. It also sensitized cells to therapeutic drug and irradiation. Significantly, miR-520b suppressed spheroid cell formation, as well as reduced expressions of multiple stemness regulators (Nestin, Twist, Nanog, Oct4). The CD44 molecule was identified as a direct target of miR-520b, as shown by the reverse correlative expressions, the response to miR-520 modulation, the luciferase reporter assay, and the functional rescue analyses. These cellular results were confirmed by a tumor xenograft mice study. Administration of miR-520b dramatically restrained tumorigenesis and liver colonization. Conversely, miR-520b silencing led to an acceleration of tumor growth. Taken together, our study demonstrated that miR-520b inhibits the malignancy of HNC through regulation of cancer stemness conversion by targeting CD44. MiR-520b may serve as an emerging therapeutic target that may be further developed for the intervention of refractory HNC.

miR-10a suppresses colorectal cancer metastasis by modulating the epithelial-to-mesenchymal transition and anoikis

MicroRNAs (miRNAs) have a critical role in tumorigenesis and metastasis, which are major obstacles of cancer therapy. However, the role of miRNAs in colorectal cancer (CRC) metastasis remains poorly understood. Here, we found that miRNA-10a (miR-10a) was upregulated in primary CRC tissues and cell line (SW480) derived from primary CRC compared with metastatic cancer tissues in lymph node and cell line (SW620). The differential expression of miR-10a was inversely correlated with distant metastasis and invasion depth. miR-10a promoted migration and invasion in vitro but inhibited metastasis in vivo by regulating the epithelial-to-mesenchymal transition and anoikis. Furthermore, matrix metalloproteinase 14 (MMP14) and actin gamma 1 (ACTG1) were validated as target genes of miR-10a in CRC cells. Ectopic expression of MMP14 and ACTG1 counteracted the decreased cell adhesion and anoikis resistance activities induced by miR-10a. These findings not only describe the mechanism by which miR-10a suppresses CRC metastasis but also suggest the potential prognostic and therapeutic value of miR-10a in CRC patients.

The relationship between platinum drug resistance and epithelial-mesenchymal transition

One of the most commonly used chemotherapeutics, platinum drugs are used to treat a wide range of cancer types. Although many cancers initially respond well to those drugs, drug resistance occurs frequently and different molecular mechanisms have been associated with it. However, predictive biomarkers of cellular response in specific tumour types still do not exist. Epithelial-mesenchymal transition (EMT) is a malignant cancer phenotype characterized by aggressive invasion and metastasis, and resistance to apoptosis. Recent studies indicate that EMT accompanies the development of drug resistance to a number of cancer chemotherapies. The link between these two phenomena is still not elucidated, although several important molecules involved in both these complex processes, such as transcription factors (SNAIL, TWIST, ZEB, etc.) and miRNAs (miRNA-200 family, miR-15, miR-186, etc.) have been recognized as important. This article reviews numerous unresolved issues regarding platinum drugs resistance and EMT, the complexity of the signalling networks that regulate those two phenomena and their importance in tumour response and spreading which are becoming focuses of interest of many scientists. This article also presents molecules involved in platinum resistance and EMT as possible targets for new cancer therapy.

The role of lymphangiogenesis and angiogenesis in tumor metastasis

BACKGROUND

Metastasis is the main cause of mortality in cancer patients. Two major routes of cancer cell spread are currently being recognized: dissemination via blood vessels (hematogenous spread) and dissemination via the lymphatic system (lymphogenous spread). Here, our current knowledge on the role of both blood and lymphatic vessels in cancer cell metastasis is summarized. In addition, I will discuss why cancer cells select one or both of the two routes to disseminate and I will provide a short description of the passive and active models of intravasation. Finally, lymphatic vessel density (LVD), blood vessel density (BVD), interstitial fluid pressure (IFP) and tumor hypoxia, as well as regional lymph node metastasis and the recently discovered primo vascular system (PVS) will be highlighted as important factors influencing tumor cell motility and spread and, ultimately, clinical outcome.

CONCLUSIONS

Lymphangiogenesis and angiogenesis are important phenomena involved in the spread of cancer cells and they are associated with a poor prognosis. It is anticipated that new discoveries and advancing knowledge on these phenomena will allow an improvement in the treatment of cancer patients.

Endometrial androgen signaling and decidualization regulate trophoblast expansion and invasion in co-culture: A time-lapse study

INTRODUCTION

To elucidate whether trophoblast expansion and invasion are modulated by androgen signaling in an in vitro co-culture model system with decidualizing endometrial stromal cells (ESCs).

METHODS

We employed an in vitro co-culture model of early embryo implantation, consisting of human ESCs (EtsT499 cells) and spheroids generated by extravillous trophoblast (EVT) derived HTR8/Svneo. The ESCs were decidualized with 8-bromo-cAMP (8-br-cAMP) in the presence or absence of dihydrotestosterone (DHT) at various concentrations for 5 days before co-culture with EVT spheroids. Trophoblast expansion was monitored by fluorescent time-lapse imaging microscopy. ESCs motility was visualized by using CellTracker™ Orange CMRA fluorescent probe. Apoptosis of ESCs was detected by CellEvent™ Caspase-3/7^® green detection reagent. Invasion assays were performed to quantify EVT invasion through a chemotaxis cell membrane.

RESULTS

Expansion of EVT spheroids was significantly enhanced by decidualized compared to undifferentiated ESCs. This process was further stimulated if ESCs were first decidualized in the presence of DHT. In contrast to decidualized ESCs, undifferentiated cells actively migrated away from expanding EVT spheroids. Invasiveness of EVT toward decidualized ESCs was significantly attenuated in comparison to undifferentiated ESCs. DHT had no effect on EVT invasion. However, an inhibitor of intercellular gap junction communication significantly enhanced EVT invasion towards decidualized ESCs.

CONCLUSIONS

These results indicate distinct roles for androgen signaling and gap junction formation in decidual cells in regulating trophoblast expansion and invasion.

Transketolase Serves a Poor Prognosticator in Esophageal Cancer by Promoting Cell Invasion via Epithelial-Mesenchymal Transition

Background: To characterize the potential function and clinical significance of Transketolase (TKT) in esophageal cancer.

Methods: High invasive esophageal squamous cell carcinoma (ESCC) cell line CE48T/VGH was used. Cellular functions in response to TKT modulation were examined, including cell growth, migration and invasion. The underlying molecules involved in the TKT regulatory mechanism were determined by western blot and confocal microscopic analysis. Clinically, TKT expressions in 76 ESCC patients were assessed by immunohistochemical (IHC) method, and the association with treatment outcome was determined.

Results: TKT silencing inhibited cell migration and invasion but had a minimal effect on cell growth. This TKT silencing also induced the reversion of epithelial-mesenchymal transition (EMT), as evidenced by the spindle to cuboidal morphological change, increased the expression of epithelial markers (γ-catenin), and decreased the levels of mesenchymal markers (fibronectin and N-cadherin). Mechanically, TKT was shown to modulate the EMT through the pERK-Slug/Snail-associated signaling pathway. Clinically, a high level of TKT in the cancer tissues of patients with esophageal squamous cell carcinoma was associated with poor survival (P = 0.042). In the multivariate analysis, a high TKT level was also shown to be an independent unfavorable prognostic factor (Odds ratio: 1.827, 95% confidence interval: 1.045-3.196, P = 0.035).

Conclusions: TKT contributes to esophageal cancer by promoting cell invasion via meditating EMT process. Clinically, the over-expression of TKT in ESCC patients predicts poorer survival. TKT inhibition may be a useful strategy to intervene in cancer cell invasion and metastasis, which may lead to better prognosis for ESCC patients.

Attenuated LKB1-SIK1 signaling promotes epithelial-mesenchymal transition and radioresistance of non-small cell lung cancer cells

Background

Radiotherapy is one of the main therapeutic approaches for non–small cell lung cancer (NSCLC). However, radioresistant cancer cells can eventually cause tumor relapse and even fatal metastasis. It is thought that radioresistance and metastasis could be potentially linked by epithelial-mesenchymal transition (EMT). In this study, we established radioresistant NSCLC cells to investigate the potential relationship among radioresistance, EMT, and enhanced metastatic potential and the underlying mechanism involving liver kinase B1 (LKB1)-Salt-inducible kinase 1 (SIK1) signaling.

Methods

The radioresistant cell lines A549R and H1299R were generated by dose-gradient irradiation of the parental A549 and H1299 cells. The radioresistance/sensitivity was evaluated by Cell Counting Kit-8 assay, apoptosis analysis, and/or clonogenic cell survival assay. The EMT phenotype and the signaling change were assessed by Western blotting. The abilities of invasion and migration were evaluated by transwell assays and wound healing assays.

Results

The radioresistant cell lines A549R and H1299R displayed mesenchymal features with enhanced invasion and migration. Mechanistically, A549R and H1299R cells had attenuated LKB1-SIK1 signaling, which leaded to the up-regulation of Zinc-finger E-box-binding homeobox factor 1 (ZEB1)—a transcription factor that drives EMT. Re-expression of LKB1 in A549R cells reversed the EMT phenotype, whereas knockdown of LKB1 in H1299R cells further promoted the EMT phenotype. Moreover, re-expression of LKB1 in A549 cells increased the radiosensitivity, whereas knockdown of LKB1 in H1299 cells decreased the radiosensitivity.

Conclusions

Our findings suggest that attenuated LKB1-SIK1 signaling promotes EMT and radioresistance of NSCLC cells, which subsequently contributes to the enhanced metastatic potential. Targeting the LKB1-SIK1-ZEB1 pathway to suppress EMT might provide therapeutic benefits.

Mimicking Metastases Including Tumor Stroma: A New Technique to Generate a Three-Dimensional Colorectal Cancer Model Based on a Biological Decellularized Intestinal Scaffold

Tumor models based on cancer cell lines cultured two-dimensionally (2D) on plastic lack histological complexity and functionality compared to the native microenvironment. Xenogenic mouse tumor models display higher complexity but often do not predict human drug responses accurately due to species-specific differences. We present here a three-dimensional (3D) in vitro colon cancer model based on a biological scaffold derived from decellularized porcine jejunum (small intestine submucosa+mucosa, SISmuc). Two different cell lines were used in monoculture or in coculture with primary fibroblasts. After 14 days of culture, we demonstrated a close contact of human Caco2 colon cancer cells with the preserved basement membrane on an ultrastructural level as well as morphological characteristics of a well-differentiated epithelium. To generate a tissue-engineered tumor model, we chose human SW480 colon cancer cells, a reportedly malignant cell line. Malignant characteristics were confirmed in 2D cell culture: SW480 cells showed higher vimentin and lower E-cadherin expression than Caco2 cells. In contrast to Caco2, SW480 cells displayed cancerous characteristics such as delocalized E-cadherin and nuclear location of β-catenin in a subset of cells. One central drawback of 2D cultures—especially in consideration of drug testing—is their artificially high proliferation. In our 3D tissue-engineered tumor model, both cell lines showed decreased numbers of proliferating cells, thus correlating more precisely with observations of primary colon cancer in all stages (UICC I-IV). Moreover, vimentin decreased in SW480 colon cancer cells, indicating a mesenchymal to epithelial transition process, attributed to metastasis formation. Only SW480 cells cocultured with fibroblasts induced the formation of tumor-like aggregates surrounded by fibroblasts, whereas in Caco2 cocultures, a separate Caco2 cell layer was formed separated from the fibroblast compartment beneath. To foster tissue generation, a bioreactor was constructed for dynamic culture approaches. This induced a close tissue-like association of cultured tumor cells with fibroblasts reflecting tumor biopsies. Therapy with 5-fluorouracil (5-FU) was effective only in 3D coculture. In conclusion, our 3D tumor model reflects human tissue-related tumor characteristics, including lower tumor cell proliferation. It is now available for drug testing in metastatic context—especially for substances targeting tumor–stroma interactions.

Correlation of standard diffusion-weighted imaging and diffusion kurtosis imaging with distant metastases of rectal carcinoma

PURPOSE

To investigate the correlation of standard diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) with distant metastases of rectal carcinoma.

MATERIALS AND METHODS

Fifty-eight patients with rectal carcinoma (27 with distant metastasis and 31 with no metastasis) were included in this study. The apparent diffusion coefficient (ADC) value from standard DWI (b values of 0 and 1000 sec/mm(2) ), Dapp , and Kapp from DKI (b values of 0, 700, 1400, and 2000 sec/mm(2) ) were acquired with a 3.0T magnetic resonance imaging (MRI) scanner. These quantitative parameters were calculated from the entire tumors. Receiver operating characteristic curve analyses were conducted to assess the utility for discrimination of tumor with distant metastasis and those without metastasis. Parameters were compared using the independent-samples t-test.

RESULTS

The histogram metrics 10th percentile of Dapp (Dapp-10th ) and ADC values (ADC10th ) were significantly lower in the distant metastasis group than those without metastasis (972.5 ± 118.8 vs. 1121.3 ± 133.8 × 10(-6) mm(2) /s, P = 0.03; 809.2 ± 67.1 vs. 856.2 ± 72.1 × 10(-6) mm(2) /s, P = 0.03). Dapp-10th showed relatively higher area under the curve (AUC) (0.856 vs. 0.669, P = 0.024), and higher specificity (100% vs. 68%) than ADC10th did for differentiation of lesions with distant metastasis from those without metastasis.

CONCLUSION

DKI was relatively better than standard DWI in discriminating rectal carcinoma with distant metastasis from those without metastasis. J. Magn. Reson. Imaging 2016;44:221-229.