Deep learning-based vessel automatic recognition for laparoscopic right hemicolectomy

BACKGROUND

In laparoscopic right hemicolectomy (RHC) for right-sided colon cancer, accurate recognition of the vascular anatomy is required for appropriate lymph node harvesting and safe operative procedures. We aimed to develop a deep learning model that enables the automatic recognition and visualization of major blood vessels in laparoscopic RHC.

MATERIALS AND METHODS

This was a single-institution retrospective feasibility study. Semantic segmentation of three vessel areas, including the superior mesenteric vein (SMV), ileocolic artery (ICA), and ileocolic vein (ICV), was performed using the developed deep learning model. The Dice coefficient, recall, and precision were utilized as evaluation metrics to quantify the model performance after fivefold cross-validation. The model was further qualitatively appraised by 13 surgeons, based on a grading rubric to assess its potential for clinical application.

RESULTS

In total, 2624 images were extracted from 104 laparoscopic colectomy for right-sided colon cancer videos, and the pixels corresponding to the SMV, ICA, and ICV were manually annotated and utilized as training data. SMV recognition was the most accurate, with all three evaluation metrics having values above 0.75, whereas the recognition accuracy of ICA and ICV ranged from 0.53 to 0.57 for the three evaluation metrics. Additionally, all 13 surgeons gave acceptable ratings for the possibility of clinical application in rubric-based quantitative evaluations.

CONCLUSION

We developed a DL-based vessel segmentation model capable of achieving feasible identification and visualization of major blood vessels in association with RHC. This model may be used by surgeons to accomplish reliable navigation of vessel visualization.

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models, part II: anatomy of relevance to surgeons operating splenic flexure cancer

BACKGROUND

The splenic flexure is irrigated from two vascular areas, both from the middle colic and the left colic artery. The challenge for the surgeon is to connect these two vascular areas in an oncological safe procedure.

MATERIALS AND METHODS

The vascular anatomy, manually 3D reconstructed from 32 preoperative high-resolution CT datasets using Osirix MD, Mimics Medical and 3-matic Medical Datasets, were exported as STL-files, video clips, stills and supplemented with 3D printed models.

RESULTS

Our first major finding was the difference in level between the middle colic and the inferior mesenteric artery origins. We have named this relationship a mesenteric inter-arterial stair. The middle colic artery origin could be found cranial (median 3.38 cm) or caudal (median 0.58 cm) to the inferior mesenteric artery. The lateral distance between the two origins was 2.63 cm (median), and the straight distance 4.23 cm (median). The second finding was the different trajectories and confluence pattern of the inferior mesenteric vein. This vein ended in the superior mesenteric/jejunal vein (21 patients) or in the splenic vein (11 patients). The inferior mesenteric vein confluence could be infrapancreatic (17 patients), infrapancreatic with retropancreatic arch (7 patients) or retropancreatic (8 patients). Lastly, the accessory middle colic artery was present in ten patients presenting another pathway for lymphatic dissemination.

CONCLUSION

The IMV trajectory when accessible, is the solution to the mesenteric inter-arterial stair. The surgeon could safely follow the IMV to its confluence. When the IMV trajectory is not accessible, the surgeon could follow the caudal border of the pancreas.

Keratin 17 upregulation promotes cell metastasis and angiogenesis in colon adenocarcinoma

Colon adenocarcinoma (COAD), having high malignancy and poor prognosis, is the main pathological type of colon cancer. Previous studies show that Keratin 17 (KRT17) plays an important role in the development of many malignant tumors. However, its role and the molecular mechanism underlying COAD remain unclear. Using TCGA and ONCOMINE databases, as well as immunohistochemistry, we found that the expression of KRT17 was higher in COAD tissues as compared to that in the adjacent normal tissues. Cell- and animal-based experiments showed that overexpression of KRT17 promoted the invasion and metastasis of colon cancer cells while knocking down KRT17 reversed these processes both in vitro and in vivo. In addition, we also showed that KRT17 promoted the formation of new blood vessels. Mechanistically, KRT17 could regulate the WNT/β-catenin signaling pathway, and APC may be involved in this process by interacting with KRT17. In summary, these findings suggested that high expression of KRT17 could promote cell metastasis and angiogenesis of colon cancer cells by regulating the WNT/β-catenin signaling pathway. Thus, KRT17 could be a potential therapeutic target for COAD treatment.

Gut vascular barrier impairment leads to intestinal bacteria dissemination and colorectal cancer metastasis to liver

Metastasis is facilitated by the formation of a "premetastatic niche," which is fostered by primary tumor-derived factors. Colorectal cancer (CRC) metastasizes mainly to the liver. We show that the premetastatic niche in the liver is induced by bacteria dissemination from primary CRC. We report that tumor-resident bacteria Escherichia coli disrupt the gut vascular barrier (GVB), an anatomical structure controlling bacterial dissemination along the gut-liver axis, depending on the virulence regulator VirF. Upon GVB impairment, bacteria disseminate to the liver, boost the formation of a premetastatic niche, and favor the recruitment of metastatic cells. In training and validation cohorts of CRC patients, we find that the increased levels of PV-1, a marker of impaired GVB, is associated with liver bacteria dissemination and metachronous distant metastases. Thus, PV-1 is a prognostic marker for CRC distant recurrence and vascular impairment, leading to liver metastases.

Targeted Ultrasound Contrast Imaging of Tumor Vasculature With Positively Charged Microbubbles

PURPOSE

Molecular ultrasound imaging of tumor vasculature is being actively investigated with microbubble contrast agents targeted to neovasculature biomarkers. Yet, a universal method of targeting tumor vasculature independent of specific biomarkers, or in their absence, would be desirable. We report the use of electrostatic interaction to achieve adherence of microbubbles to tumor vasculature and resulting tumor delineation by ultrasound imaging.

METHODS AND MATERIALS

Microbubbles were prepared from decafluorobutane gas by amalgamation of aqueous micellar medium. Distearoyl phosphatidylcholine (DSPC) and polyethylene glycol (PEG)-stearate were used as microbubble shell-forming lipids; cationic lipid distearoyl trimethylammoniumpropane (DSTAP) was included to introduce positive electrostatic charge. Microbubbles were subjected to flotation in normal gravity, to remove larger particles. Murine colon adenocarcinoma tumor (MC38, J. Schlom, National Institutes of Health) was inoculated in the hind leg of C57BL/6 mice. Contrast ultrasound imaging was performed under isoflurane anesthesia, using a clinical imaging system in low power mode, with tissue signal suppression (contrast pulse sequencing, 7 MHz, 1 Hz; Mechanical Index, 0.2). The ultrasound probe was positioned to monitor the tumor and contralateral leg muscle; microbubble contrast signal was monitored for 30 minutes or more, after intravenous bolus administration of 2.10 microbubbles. Individual time point frames were extracted from ultrasound video recording and analyzed with ImageJ.

RESULTS

Mean bubble diameter was ~1.6 to 2 μm; 99.9% were less than 5 μm, to prevent blocking blood flow in capillaries. For cationic DSTAP-carrying microbubbles, contrast signal was observed in the tumor beyond 30 minutes after injection. As the fraction of positively charged lipid in the bubble shell was increased, adherent contrast signal in the tumor also increased, but accumulation of DSTAP-microbubbles in the normal muscle increased as well. For bubbles with the highest positive charge tested, DSTAP-DSPC molar ratio 1:4, at 10 minutes after intravenous administration of microbubbles, the contrast signal difference between the tumor and normal muscle was 1.5 (P < 0.005). At 30 minutes, tumor/muscle contrast signal ratio improved and reached 2.1. For the DSTAP-DSPC 1:13 preparation, tumor/muscle signal ratio exceeded 3.6 at 10 minutes and reached 5.4 at 30 minutes. Microbubbles with DSTAP-DSPC ratio 1:22 were optimal for tumor targeting: at 10 minutes, tumor/muscle signal ratio was greater than 7 (P < 0.005); at 30 minutes, greater than 16 (P < 0.01), sufficient for tumor delineation.

CONCLUSIONS

Cationic microbubbles are easy to prepare. They selectively accumulate in the tumor vasculature after intravenous administration. These microbubbles provide target-to-control contrast ratio that can exceed an order of magnitude. Adherent microbubbles delineate the tumor mass at extended time points, at 30 minutes and beyond. This may allow for an extension of the contrast ultrasound examination time. Overall, positively charged microbubbles could become a universal ultrasound contrast agent for cancer imaging.

Fibroblast-specific ERK5 deficiency changes tumor vasculature and exacerbates tumor progression in a mouse model

The roles of cancer-associated fibroblasts (CAFs) have been studied in the tumor progression, and CAFs are expected to become the new targets for cancer pharmacotherapies. CAFs contribute to tumor cell survival and proliferation, tumor angiogenesis, immune suppression, tumor inflammation, tumor cell invasion and metastasis, and extracellular matrix remodeling. However, detailed mechanisms of how CAFs function in the living system remain unclear. CAFs include α-smooth muscle actin, expressing activated fibroblasts similar to myofibroblasts, and are highly capable of producing collagen. Several reports have demonstrated the contributions of extracellular-signal-regulated kinase 5 (ERK5) in fibroblasts to the fibrotic processes; however, the roles of CAF-derived ERK5 remain unclear. To investigate the roles of CAF-derived ERK5 in the tumor progression, we created mice lacking the ERK5 gene specifically in fibroblasts. Colon-26 mouse colon cancer cells were implanted into the mice subcutaneously, and the histological analyses of the tumor tissue were performed after 2 weeks. Immunofluorescence analyses showed that recipient-derived fibroblasts existed within the tumor tissue. The present study demonstrated that fibroblast-specific ERK5 deficiency exacerbated tumor progression and it was accompanied with thicker tumor vessel formation and the increase in the number of activated fibroblasts. We combined the results of The Cancer Genome Atlas (TCGA) database analysis with our animal studies, and indicated that regulating ERK5 activity in CAFs or CAF invasion into the tumor tissue can be important strategies for the development of new targets in cancer pharmacotherapies.

Co-Culturing of Endothelial and Cancer Cells in a Nanofibrous Scaffold-Based Two-Layer System

Angiogenesis is critical for local tumor growth. This study aimed to develop a three-dimensional two-layer co-culture system to investigate effects of cancer cells on the growth of endothelial cells (ECs). Poly(ε-caprolactone) (PCL) nanofibrous membranes were generated via electrospinning of PCL in chloroform (C-PCL-M) and chloroform and dimethylformamide (C/DMF-PCL-M). We assembled a two-layer co-culture system using C-PCL-M and C/DMF-PCL-M for EC growth in the upper layer with co-cultured cancer cells in the lower layer. In the absence of vascular endothelial growth factor (VEGF), growth of bEND.3 ECs decreased on C/DMF-PCL-M but not on C-PCL-M with time. Growth of bEND.3 cells on C/DMF-PCL-M was enhanced through co-culturing of CT26 cancer cells and enhanced growth of bEND.3 cells was abrogated with anti-VEGF antibodies and sorafenib. However, EA.hy926 ECs displayed steady growth and proliferation on C/DMF-PCL-M, and their growth was not further increased through co-culturing of cancer cells. Moreover, chemical hypoxia in CT26 cancer cells upon treatment with CoCl₂ enhanced the growth of co-cultured bEND.3 cells in the two-layer system. Thus, EC growth on the nanofibrous scaffold is dependent on the types of ECs and composition of nanofibers and this co-culture system can be used to analyze EC growth induced by cancer cells.

"Caudal-to-cranial" plus "artery first" technique with beyond D3 lymph node dissection on the right midline of the superior mesenteric artery for the treatment of right colon cancer: is it more in line with the principle of oncology?

OBJECTIVE

To explore the feasibility and application value of a "caudal-to-cranial" plus "artery first" technique with beyond D3 lymph node dissection on the right midline of the superior mesenteric artery (SMA) for the treatment of right colon cancer METHODS: Clinical data consisting of 168 right colon cancer cases under going laparoscopic D3 radical resection, including 84 cases of "caudal-to-cranial" plus "artery first" technique with beyond D3 lymph node dissection on the right midline of the SMA (CC + SMA group) and 84 cases of conventional medial approach plus dissection around the superior mesenteric vein (MA + SMV group), from January 2017 to March 2018 were retrospectively analyzed. For CC + SMA group, our surgical method was to isolate the mesocolon using a caudal-to-cranial pathway and ligate blood vessels along the midline of the SMA.

RESULTS

The baseline data was not significantly different between the two groups (all p > 0.05). The mean operation time and intraoperative blood loss in the CC + SMA and the MA + SMV groups were 170.04 ± 43.10 versus 172.33 ± 41.84 min and 91.07 ± 55.12 versus 77.38 ± 40.21 ml, respectively, which has no significant difference (p > 0.05). The mean number of total and positive harvested lymph nodes in the two groups were 29.44 ± 5.90 versus 26.21 ± 6.64 (p < 0.05) and 2.57 ± 1.93 versus 2.51 ± 1.05, respectively (p > 0.05). Compared with the MA + SMV group, there was no significant difference in total postoperative complication rate in the CC + SMA group. The time to pull out drainage tube in the CC + SMA group was longer than MA + SMV group (4.05 ± 1.79 versus 3.38 ± 1.99 day; p = 0.022).

CONCLUSION

It is safe and feasible for the "caudal-to-cranial" plus "artery first" technique with beyond D3 lymph node dissection on the right midline of the SMA in right colon cancer. It may have some advantages in the number of lymph nodes dissection, and the long-term prognosis remains to be expected.

Extracellular Vesicles Containing MicroRNA-92a-3p Facilitate Partial Endothelial-Mesenchymal Transition and Angiogenesis in Endothelial Cells

Extracellular vesicles (EVs) are nanometer-sized membranous vesicles used for primitive cell-to-cell communication. We previously reported that colon cancer-derived EVs contain abundant miR-92a-3p and have a pro-angiogenic function. We previously identified Dickkopf-3 (Dkk-3) as a direct target of miR-92a-3p; however, the pro-angiogenic function of miR-92a-3p cannot only be attributed to downregulation of Dkk-3. Therefore, the complete molecular mechanism by which miR-92a-3p exerts pro-angiogenic effects is still unclear. Here, we comprehensively analyzed the gene sets affected by ectopic expression of miR-92a-3p in endothelial cells to elucidate processes underlying EV-induced angiogenesis. We found that the ectopic expression of miR-92a-3p upregulated cell cycle- and mitosis-related gene expression and downregulated adhesion-related gene expression in endothelial cells. We also identified a novel target gene of miR-92a-3p, claudin-11. Claudin-11 belongs to the claudin gene family, which encodes essential components expressed at tight junctions (TJs). Disruption of TJs with a concomitant loss of claudin expression is a significant event in the process of epithelial-to-mesenchymal transition. Our findings have unveiled a new EV-mediated mechanism for tumor angiogenesis through the induction of partial endothelial-to-mesenchymal transition in endothelial cells.

PTHrP treatment of colon cancer cells promotes tumor associated-angiogenesis by the effect of VEGF

We showed that Parathyroid Hormone-related Peptide (PTHrP) induces proliferation, migration, survival and chemoresistance via MAPKs and PI3K/AKT pathways in colorectal cancer (CRC) cells. The objective of this study was to investigate if PTHrP is also involved in tumor angiogenesis. PTHrP increased VEGF expression and the number of structures with characteristics of neoformed vessels in xenografts tumor. Also, PTHrP increased mRNA levels of VEGF, HIF-1α and MMP-9 via ERK1/2 and PI3K/Akt pathways in Caco-2 and HCT116 cells. Tumor conditioned media (TCMs) from both cell lines treated with PTHrP increases the number of cells, the migration and the tube formation in the endothelial HMEC-1 cells, whereas the neutralizing antibody against VEGF diminished this response. In contrast, PTHrP by direct treatment only increased ERK1/2 phosphorylation and the HMEC-1 cells number. These results provide the first evidence related to the mode of action of PTHrP that leads to its proangiogenic effects in the CRC.

Antiproliferative effect of p-Coumaric acid targets UPR activation by downregulating Grp78 in colon cancer

p-CA is a naturally occurring phenolic acid present in most plants and in all commonly consumed vegetables and fruits. Here we demonstrated the anti-cancer effect of the food borne phytochemical p-CA both in vitro and in vivo models of colon cancer using growth rate and tumor incidence as endpoints. Glucose regulated protein (GRP78) induction and UPR activation plays a key role in oncogenic progression, therefore increased dependence of cancer cells on these UPR signaling pathways for survival can be exploited for anti-cancer research. Hence we investigated the effect of p-CA on Grp78 a molecular chaperone often upregulated in colon cancer and its impact on unfolded protein response (UPR). Administration of the procarcinogen 1,2- dimethylhydrazine (DMH) causes Grp78 upregulation and tumor adaptation via UPR activation. The adaptive activity of UPR activates antiapoptotic NF-κB that results in upregulation of the markers of inflammation and angiogenesis. Supplementation of p-CA downregulated Grp78 and activated UPR mediated apoptosis both in in vitro and in vivo models of colon cancer. Further we observed that p-CA significantly reduced inflammation by decreasing the expression of cytokines COX-2, IL-6, TNF-α and PGE2 as analyzed by q-PCR and also reduced the expression of p-p65 and p-IκBα as analyzed by western blot. Further mechanistic insights revealed that p-CA inhibits Grp78 upregulation in cancer cells through activation of PERK-eIF2α-ATF-4-CHOP pathway that culminates in apoptosis inducing effect of p-CA.

[Five-Year Survival of Two Patients with Para-Aortic Lymph Node Metastasis Treated with Four FOLFOX6and Four FOLFIRI Courses in Combination with Bevacizumab]

Patients with metastatic colon cancer can be treated with alternating courses of FOLFOX6 and FOLFIRI in order to reduce their adverse events. We report 2 patients with para-aortic lymph node metastasis treated with 4 courses each of FOLFOX6 and FOLFIRI in combination with bevacizumab, which led to a complete response. Case 1: The patient was a 53-year-old woman with transvers colon cancer tub2 pSS, ly3, v2, n4, H0, P0. Case 2: The patient was a 60-year-old woman with upper rectal cancer tub1 pSS, ly3, v3, n4, H0, P0. The administration of tegafur/uracil plus oral Leucovorin was continued for 6 months. Furthermore, only the administration of oral doxifluridine was continued for 4 years. Complete response has been maintained for over 5 years since resection. Four courses each of FOLFOX6 and FOLFIRI in combination with bevacizumab will not only provide a remission rate of 100% but will also be effective radical therapy for patients with para-aortic lymph node metastasis.

MORPHOLOGICAL CHARACTERISTICS OF ANGIOGENESIS IN ADENOCARCINOMA OF COLON

The study of the process of angiogenesis and microcirculation with the help of modern methods of morphological research including type and maturity of the tumor, location and is considered a problem of special importance and value. The purpose of this research is to study the particularity of angiogenesis and microcirculation in colon adenocarcinomas. The human tissue samples of colon adenocarcinoma (19 cases, 40 observation sites) were studied by light microscopic, electron- microscopic, electron-radiographic and immunohistochemical methods. For electron-radiographic studies - the sections of tissue were incubated separately in radioactive precursor 3H - thymidine and 3H - uridine. For immohistochemical studies markers CD34 and VEGF-A were used. According to analyzed data, de novo hyperplasia of endotheliocytes was detected by positive reaction on VEGF-A and CD34 markers in adenocarcinoma vascular structures. Special interest provide the VEGF-A and CD34 expression in stromal components. There is also an increase DNA synthesis in adenocarcinoma. Intra-tumor neoangiogenesis and changes in microcirculation are one of the most important factors regulating the processes of proliferation of atypical cells. The data obtained makes it possible to judge the prognosis, metastasis, and also the biopotential of neoplastic progression.

Imperatorin suppresses proliferation and angiogenesis of human colon cancer cell by targeting HIF-1α via the mTOR/p70S6K/4E-BP1 and MAPK pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica dahurica is a commonly used traditional Chinese medicine to treat migraine headache, toothache and cancer. Imperatorin is an active natural furocoumarin component originating from Angelica dahurica and has been shown to exhibit multiple bioeffector functions, including anti-cancer activity. However, the mechanism by which imperatorin inhibits tumor growth is not fully understood.

AIM OF THE STUDY

The aim of this study was to investigate the effectiveness of imperatorin as a treatment of cancer and to identify the underlying mechanisms of its anticancer activity.

MATERIALS AND METHODS

HCT116, HeLa, and Hep3B cells were used in this study. Major assays were promoter-reporter gene assay, MTT, western blot analysis, immunofluorescence assay, reverse transcription-PCR (RT-PCR), flow cytometric analysis, clonogenic assay, EdU labeling and immunofluorescence, xenografted assay, and VEGF ELISA.

RESULTS

We here demonstrated the effect of imperatorin on hypoxia-inducible factor-1 (HIF-1) activation. Imperatorin showed a potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1α protein dose-dependently, whereas it did not affect the expressions of HIF-1β and topoisomerase-I (Topo-I). Further analysis revealed that imperatorin inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. Moreover, the phosphorylation levels of mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6K), eIF4E binding protein-1 (4E-BP1), eukaryotic initiation factor 4E (eIF4E), extracellular signal-regulated kinase-1/2 (ERK1/2), SAPK/JNK and p38 were significantly suppressed by imperatorin. Furthermore, imperatorin prevented hypoxia-induced expression of HIF-1 target genes and flow cytometric analysis indicated that imperatorin induced G1 phase arrest in human colon cancer cell (HCT116). We found that imperatorin administration inhibits tumor growth and blocks tumor angiogenesis in a xenograft tumor model.

CONCLUSIONS

These results show that imperatorin inhibited HIF-1α protein synthesis by downregulating the mTOR/p70S6K/4E-BP1 and MAPK pathways. These conclusions suggest that imperatorin is an effective inhibitor of HIF-1 and provide new perspectives into the mechanism of its anticancer activity.

Acute tumour response to a bispecific Ang-2-VEGF-A antibody: insights from multiparametric MRI and gene expression profiling

BACKGROUND

To assess antivascular effects, and evaluate clinically translatable magnetic resonance imaging (MRI) biomarkers of tumour response in vivo, following treatment with vanucizumab, a bispecific human antibody against angiopoietin-2 (Ang-2) and vascular endothelial growth factor-A (VEGF-A).

METHODS

Colo205 colon cancer xenografts were imaged before and 5 days after treatment with a single 10 mg kg(-1) dose of either vanucizumab, bevacizumab (anti-human VEGF-A), LC06 (anti-murine/human Ang-2) or omalizumab (anti-human IgE control). Volumetric response was assessed using T2-weighted MRI, and diffusion-weighted, dynamic contrast-enhanced (DCE) and susceptibility contrast MRI used to quantify tumour water diffusivity (apparent diffusion coefficient (ADC), × 10(6) mm(2) s(-1)), vascular perfusion/permeability (K(trans), min(-1)) and fractional blood volume (fBV, %) respectively. Pathological correlates were sought, and preliminary gene expression profiling performed.

RESULTS

Treatment with vanucizumab, bevacizumab or LC06 induced a significant (P<0.01) cytolentic response compared with control. There was no significant change in tumour ADC in any treatment group. Uptake of Gd-DTPA was restricted to the tumour periphery in all post-treatment groups. A significant reduction in tumour K(trans) (P<0.05) and fBV (P<0.01) was determined 5 days after treatment with vanucizumab only. This was associated with a significant (P<0.05) reduction in Hoechst 33342 uptake compared with control. Gene expression profiling identified 20 human genes exclusively regulated by vanucizumab, 6 of which are known to be involved in vasculogenesis and angiogenesis.

CONCLUSIONS

Vanucizumab is a promising antitumour and antiangiogenic treatment, whose antivascular activity can be monitored using DCE and susceptibility contrast MRI. Differential gene expression in vanucizumab-treated tumours is regulated by the combined effect of Ang-2 and VEGF-A inhibition.

Styrene maleic acid-encapsulated paclitaxel micelles: antitumor activity and toxicity studies following oral administration in a murine orthotopic colon cancer model

Oral administration of paclitaxel (PTX), a broad spectrum anticancer agent, is challenged by its low uptake due to its poor bioavailability, efflux through P-glycoprotein, and gastrointestinal toxicity. We synthesized PTX nanomicelles using poly(styrene-co-maleic acid) (SMA). Oral administration of SMA-PTX micelles doubled the maximum tolerated dose (60 mg/kg vs 30 mg/kg) compared to the commercially available PTX formulation (PTX [Ebewe]). In a murine orthotopic colon cancer model, oral administration of SMA-PTX micelles at doses 30 mg/kg and 60 mg/kg reduced tumor weight by 54% and 69%, respectively, as compared to the control group, while no significant reduction in tumor weight was observed with 30 mg/kg of PTX (Ebewe). In addition, toxicity of PTX was largely reduced by its encapsulation into SMA. Furthermore, examination of the tumors demonstrated a decrease in the number of blood vessels. Thus, oral delivery of SMA-PTX micelles may provide a safe and effective strategy for the treatment of colon cancer.

Synergistic Effect of SN-38 in Combination with Cetuximab on Angiogenesis and Cancer Cell Invasion

BACKGROUND

The combination of irinotecan, a topoisomerase I inhibitor with cetuximab, an antibody against epidermal growth factor receptor, produces synergistic and beneficial effects in patients with irinotecan-refractory colorectal cancer. Our hypothesis was that synergistic effects could be due to anti-angiogenesis and anti-invasion, but not to cytotoxicity.

MATERIALS AND METHODS

Cytotoxicity was assessed by viability test and flow cytometry. Anti-angiogenesis, anti-invasion were studied by the endothelial cell capillary-like network formation and transmigration through an extracellular matrix. Protein kinase B (PKB, frequently cited as AKT), and extracellular signal-regulated kinases (ERK) activation was assayed by cell-based enzyme-linked immunosorbent assay (ELISA).

RESULTS

Combinations of SN-38 (the active of irinotecan) and cetuximab did not induce any synergistic cytotoxicity confirmed by viability test and cell-cycle analyses. Interestingly, their combination produced synergistic anti-angiogenesis and anti-invasion activities revealed by endothelial cell capillary-like network formation and cell invasion tests. Subsequently, their combination attenuated either expression or phosphorylation of AKT and ERK1/2 using cell-based ELISA.

CONCLUSION

SN-38/cetuximab combination has synergistic anti-angiogenesis and anti-invasion activities mediated by down-regulation of phosphatidylinositol-3-kinases/AKT and mitogen-activated protein kinase/ERK pathways.

[Effect of colon cancer cell-derived IL-1α on the migration and proliferation of vascular endothelial cells]

OBJECTIVE

To explore the effect of colon cancer cell-derived interleukin-1α on the migration and proliferation of human umbilical vein endothelial cells as well as the role of IL-1α and IL-1ra in the angiogenesis process.

METHODS

Western blot was used to detect the expression of IL-1α and IL-1R1 protein in the colon cancer cell lines with different liver metastatic potential. We also examined how IL-1α and IL-1ra influence the proliferation and migration of umbilical vascular endothelial cells assessed by PreMix WST-1 assay and migration assay, respectively. Double layer culture technique was used to detect the effect of IL-1α on the proliferation and migration of vascular endothelial cells and the effect of IL-1ra on the vascular endothelial cells.

RESULTS

Western blot analysis showed that IL-1α protein was only detected in highly metastatic colon cancer HT-29 and WiDr cells, but not in the lowly metastatic CaCo-2 and CoLo320 cells.Migration assay showed that there were significant differences in the number of penetrated cells between the control (17.9±3.6) and 1 ng/ml rIL-1α group (23.2±4.2), 10 ng/ml rIL-1α group (31.7±4.5), and 100 ng/ml rIL-1α group (38.6±4.9), showing that it was positively correlated with the increasing concentration of rIL-1α (P<0.01 for all). The proliferation assay showed that the absorbance values were 1.37±0.18 in the control group, and 1.79±0.14 in the 1 ng/ml rIL-1α group, 2.14±0.17 in the 10 ng/ml rIL-1α group, and 2.21±0.23 in the 100 ng/ml rIL-1α group, showing a positive correlation with the increasing concentration of rIL-1α(P<0.01 for all). IL-1ra significantly inhibited the proliferation and migration of vascular endothelial cells (P<0.01). The levels of VEGF protein were (1.697±0.072) ng/ml, (3.507±0.064)ng/ml and (4.139±0.039)ng/ml in the control, HUVECs+ IL-1α and HUVECs+ HT-29 co-culture system groups, respectively, showing a significant difference between the control and HUVECs+ 10 pg/ml rIL-1α groups and between the control and HUVECs+ HT-29 groups (P<0.01 for both).

CONCLUSIONS

Our findings indicate that colon cancer cell-derived IL-1α plays an important role in the liver metastasis of colon cancer through increased VEGF level of the colon cancer cells and enhanced vascular endothelial cells proliferation, migration and angiogenesis, while IL-1ra can suppress the effect of IL-1α and inhibit the angiogenesis in colon cancer.

Colon Cancer Growth and Dissemination Relies upon Thrombin, Stromal PAR-1, and Fibrinogen

Thrombin-mediated proteolysis is a major determinant of metastasis, but is not universally important for primary tumor growth. Here, we report that colorectal adenocarcinoma represents one important exception whereby thrombin-mediated functions support both primary tumor growth and metastasis. In contrast with studies of multiple nongastrointestinal cancers, we found that the growth of primary tumors formed by murine and human colon cancer cells was reduced in mice by genetic or pharmacologic reduction of circulating prothrombin. Reduced prothrombin expression was associated with lower mitotic indices and invasion of surrounding tissue. Mechanistic investigations revealed that thrombin-driven colonic adenocarcinoma growth relied upon at least two targets of thrombin-mediated proteolysis, protease-activated receptor-1 (PAR-1) expressed by stromal cells and the extracellular matrix protein, fibrinogen. Colonic adenocarcinoma growth was reduced in PAR-1-deficient mice, implicating stromal cell-associated PAR-1 as one thrombin target important for tumor outgrowth. Furthermore, tumor growth was dramatically impeded in fibrinogen-deficient mice, offering the first direct evidence of a critical functional role for fibrinogen in malignant tumor growth. Tumors harvested from fibrinogen-deficient mice displayed a relative reduction in cell proliferative indices, as well as increased tumor necrosis and decreased tumor vascular density. Collectively, our findings established a functional role for thrombin and its targets PAR-1 and fibrinogen in the pathogenesis of colonic adenocarcinoma, supporting tumor growth as well as local invasion and metastasis.

Impact of image preprocessing methods on polyp localization in colonoscopy frames

In this paper we present our image preprocessing methods as a key part of our automatic polyp localization scheme. These methods are used to assess the impact of different endoluminal scene elements when characterizing polyps. More precisely we tackle the influence of specular highlights, blood vessels and black mask surrounding the scene. Experimental results prove that the appropriate handling of these elements leads to a great improvement in polyp localization results.

Alternative splicing of TIA-1 in human colon cancer regulates VEGF isoform expression, angiogenesis, tumour growth and bevacizumab resistance

The angiogenic capability of colorectal carcinomas (CRC), and their susceptibility to anti-angiogenic therapy, is determined by expression of vascular endothelial growth factor (VEGF) isoforms. The intracellular protein T-cell Intracellular Antigen (TIA-1) alters post-transcriptional RNA processing and binds VEGF-A mRNA. We therefore tested the hypothesis that TIA-1 could regulate VEGF-A isoform expression in colorectal cancers. TIA-1 and VEGF-A isoform expression was measured in colorectal cancers and cell lines. We discovered that an endogenous splice variant of TIA-1 encoding a truncated protein, short TIA-1 (sTIA-1) was expressed in CRC tissues and invasive K-Ras mutant colon cancer cells and tissues but not in adenoma cell lines. sTIA-1 was more highly expressed in CRC than in normal tissues and increased with tumour stage. Knockdown of sTIA-1 or over-expression of full length TIA-1 (flTIA-1) induced expression of the anti-angiogenic VEGF isoform VEGF-A165b. Whereas flTIA-1 selectively bound VEGF-A165 mRNA and increased translation of VEGF-A165b, sTIA-1 prevented this binding. In nude mice, xenografted colon cancer cells over-expressing flTIA-1 formed smaller, less vascular tumours than those expressing sTIA-1, but flTIA-1 expression inhibited the effect of anti-VEGF antibodies. These results indicate that alternative splicing of an RNA binding protein can regulate isoform specific expression of VEGF providing an added layer of complexity to the angiogenic profile of colorectal cancer and their resistance to anti-angiogenic therapy.

Granulocyte colony-stimulating factor-producing undifferentiated carcinoma of the colon mimicking a pulmonary giant cell carcinoma: a case showing overexpression of CD44 along with highly proliferating nestin-positive tumor vessels

Granulocyte colony-stimulating factor (G-CSF)-producing tumors are known for their aggressive behavior. Only four cases of G-CSF-producing colorectal carcinoma have been previously reported. Herein, we present a case of an undifferentiated carcinoma of the descending colon showing G-CSF production and giant cell carcinoma morphology in a 93-year-old woman. A tumor with a diameter of 80 mm was identified in the descending colon via computed tomography. Descending colectomy was performed involving the abdominal wall where tumor invasion was observed. The white blood cell count, which was elevated before resection, decreased to normal levels after intervention. However, local recurrence at the resected site was detected 39 days after surgery. Upon recurrence, increased white blood cell counts and serum G-CSF were seen. The patient died because of respiratory failure 98 days after colectomy. By using immunohistochemistry, G-CSF expression was detected in tumor cells in the resected specimen, along with overexpression of CD44 and highly proliferating nestin-positive tumor vessels. The poor clinical outcome of this patient is consistent with previous reports that the expression of these three molecules predict poor prognosis. While G-CSF can be a therapeutic target considering its auto/paracrine function to induce tumor growth via the G-CSF receptor, CD44 and nestin may also be possible candidate therapeutic targets. Further studies are required to assess the efficacy of treatments targeting these three molecules.

Tumour biomechanical response to the vascular disrupting agent ZD6126 in vivo assessed by magnetic resonance elastography

BACKGROUND

Magnetic resonance elastography (MRE) is an emerging imaging technique that affords non-invasive quantitative assessment and visualization of tissue mechanical properties in vivo.

METHODS

In this study, MRE was used to quantify (kPa) the absolute value of the complex shear modulus |G*|, elasticity Gd and viscosity Gl of SW620 human colorectal cancer xenografts before and 24 h after treatment with either 200 mg kg(-1) of the vascular disrupting agent ZD6126 (N-acetylcolchinol-O-phosphate) or vehicle control, and the data were compared with changes in water diffusivity measured by diffusion-weighted magnetic resonance imaging.

RESULTS

A heterogeneous distribution of |G*|, Gd and Gl was observed pre-treatment with an intertumoral coefficient of variation of 13% for |G*|. There were no significant changes in the vehicle-treated cohort. In contrast, ZD6126 induced a significant decrease in the tumour-averaged |G*| (P<0.01), Gd (P<0.01) and Gl (P<0.05), and this was associated with histologically confirmed central necrosis. This reduction in tumour viscoelasticity occurred at a time when no significant change in tumour apparent diffusion coefficient (ADC) was observed.

CONCLUSIONS

These data demonstrate that MRE can provide early imaging biomarkers for treatment-induced tumour necrosis.

Leflunomid reduziert den Angiogenesescore und das Tumorwachstum subkutan implantierter Kolonkarzinomzellen im Mausmodell

BACKGROUND

The inhibition of tumorangiogenesis may be of importance in the additive treatment of various cancers. Leflunomide, a drug which has been approved in Germany for the therapy of rheumatoid arthritis, inhibits the activity of several growth factors in vitro. The aim of this study was to investigate the effects of the drug on tumor angiogenesis in a nude mouse model.

MATERIALS AND METHODS

A total of 40 nude mice were injected with human colon carcinoma cells. Following randomization in 4 groups, therapy started on day five. Group 1 was treated daily with orally administered Leflunomide (35 mg/kg) dissolved in 1.5% Carboxymethylcellulose (CMC). Group 2 served as a control group and received 1 ml CMC orally per day. The animals of group 3 were treated daily with 35 mg Leflunomide/kg KG and 500 mg Uridine/kg dissolved in 1 ml Nacl 0.9% intraperitoneally. The 4th group again served as a control group and received only 500 mg Uridine/kg intraperitoneally each day. The main outcome criterion was the angiogenesis score (AS). In addition, the tumor volume and tumor weight were also assessed. The AS was determined by immunohistochemistry using an antibody against factor VIII related antigen.

RESULTS

All animals tolerated the procedure well. In the Leflunomide and the Leflunomide/Uridine group the angiogenesis score (p < 0.01), the tumor volume (p < 0.01) and the tumor weight (p < 0.01) were lower compared to the respective control groups.

CONCLUSION

The administration of Leflunomide leads to a significant reduction of tumor weight and tumor volume following subcutaneous injection of human colon carcinoma cells in a nude mouse model. This could be due to the reduction of tumor angiogenesis. Following further experimental and clinical studies, Leflunomide may come to play a role in the additive treatment of colonic carcinoma.

PPARδ deficiency disrupts hypoxia-mediated tumorigenic potential of colon cancer cells

Peroxisome proliferator-activated receptor (PPAR) δ is highly expressed in colon epithelial cells and closely linked to colon carcinogenesis. However, the role of PPARδ in colon cancer cells in a hypoxic tumor microenvironment is not fully understood. We found that expression of the tumor-promoting cytokines, IL-8 and VEGF, induced by hypoxia (<1% O2) and deferoxamine (a hypoxia mimetic) was significantly attenuated in PPARδ-deficient HCT116 colon cancer cells. Consequently, PPARδ-knockout colon cancer cells exposed to hypoxia and deferoxamine failed to stimulate endothelial cell vascularization and macrophage migration/proliferation, whereas wild-type cells were able to induce angiogenesis and macrophage activation in response to hypoxic stress. Hypoxic stress induced transcriptional activation of PPARδ, but not its protein expression, in HCT116 cells. Exogenous expression of p300 potentiated deferoxamine-induced PPARδ transactivation, while siRNA knockdown of p300 abolished hypoxia- and deferoxamine-induced PPARδ transactivation. PPARδ associated with p300 upon hypoxic stress as demonstrated by coimmunoprecipitation studies. PI3K inhibitors or siRNA knockdown of Akt suppressed the PPARδ transactivation induced by hypoxia and deferoxamine in HCT116 cells, leading to decreased expression of IL-8 and VEGF. Collectively, these results reveal that PPARδ is required for hypoxic stress-mediated cytokine expression in colon cancer cells, resulting in promotion of angiogenesis, macrophage recruitment, and macrophage proliferation in the tumor microenvironment. p300 and the PI3K/Akt pathway play a role in the regulation of PPARδ transactivation induced by hypoxic stress. Our results demonstrate the positive crosstalk between PPARδ in tumor cells and the hypoxic tumor microenvironment and provide potential therapeutic targets for colon cancer.

VEGF and colon cancer growth beyond angiogenesis: does VEGF directly mediate colon cancer growth via a non-angiogenic mechanism?

In this article we review the role of vascular endothelial growth factor (VEGF) in colon cancer growth and the underlying mechanisms. Angiogenesis, the growth of new capillary blood vessels in the body, is critical for tissue injury healing and cancer growth. In 1971, Judah Folkman proposed the concept that tumor growth beyond 2 mm is critically dependent on angiogenesis. Tumors including colon cancers release angiogenic growth factors that stimulate blood vessels to grow into the tumors thus providing oxygen and nutrients that enable exponential growth. VEGF is the most potent angiogenic growth factor. Several studies have highlighted the role of VEGF in colon cancer, specifically in the stimulation of angiogenesis. This role of VEGF is strongly supported by studies showing that inhibition of VEGF using the blocking antibody, bevacizumab, results in decreased angiogenesis and abrogation of cancer growth. In the United States, bevacizumab in combination with chemotherapy is FDA approved for the treatment of metastatic colon cancer. However, the source of VEGF in colon cancer tissue, the mechanisms of VEGF generation in colon cancer cells and the molecular pathways involved in VEGF mediated angiogenesis in colon cancer are not fully known. The possibility that VEGF directly stimulates cancer cell growth in an autocrine manner has not been explored in depth.

Peritumoral inflammatory reaction in colon cancer. Histological and immunohistochemical study

Colorectal cancer is one of the most frequent malignancies with an increasing incidence and prevalence. As in other malignancies, nor etiology, neither pathogenesis of colorectal cancer are well known. The link between inflammation and colorectal cancer has become a major concern in the past 20 years, since several clinical trials have shown that patients with chronic inflammatory intestinal diseases have a much higher risk of colorectal neoplasm development. In our study, we analyzed peritumoral inflammatory reaction from histological and immunohistochemical point of view, in 23 cases of stage III colon adenocarcinoma, operated during 2014. The immunohistochemical techniques were used in order to emphasize B-lymphocytes, T-lymphocytes, macrophages, mast cells and blood vessels. In all cases, we have noted the involvement of inflammatory cells present in peritumoral and tumoral stroma, in variable degrees, regardless the differentiation of the neoplasm or other known histological feature. In particular, the macrophages were the most numerous, especially in areas of tumoral necrosis, but also present in the lumen of tumoral glands, or even within tumoral cell islands. Mast cells appeared more abundant in the tumor stroma around blood vessels and were absent in the areas of tumor necrosis, while B-cells were almost absent. Tumor stroma showed a well-developed vascular network, consisting mainly of small vessels that do not seem to correlate with the intensity of the inflammatory reaction.

YL529, a novel, orally available multikinase inhibitor, potently inhibits angiogenesis and tumour growth in preclinical models

BACKGROUND AND PURPOSE

Targeted chemotherapy using small-molecule inhibitors of angiogenesis and proliferation is a promising strategy for cancer therapy.

EXPERIMENTAL APPROACH

YL529 was developed via computer-aided drug design, de novo synthesis and high-throughput screening. The biochemical, pharmacodynamic and toxicological profiles of YL529 were investigated using kinase and cell viability assays, a mouse tumour cell-containing alginate bead model, a zebrafish angiogenesis model and several human tumour xenograft models in athymic mice.

KEY RESULTS

In vitro, YL529 selectively inhibited the activities of VEGFR2/VEGFR3 and serine/threonine kinase RAF kinase. YL529 inhibited VEGF165 -induced phosphorylation of VEGFR2, as well as the proliferation, migration, invasion and tube formation of human umbilical vascular endothelial cells. It also significantly blocked vascular formation and angiogenesis in the zebrafish model. Moreover, YL529 strongly attenuated the proliferation of A549 cells by disrupting the RAF/mitogen-activated protein (MAP) or extracellular signal-regulated kinase (Erk) kinase (MEK) kinase kinase/MAPK pathway. Oral administration of YL529 (37.5-150 mg(-1) ·kg(-1) ·day(-1) ) to nude mice bearing established tumour xenografts significantly prevented the growth (60-80%) of A549, SPC-A1, A375, OS-RC-2 and HCT116 tumours without detectable toxicity. YL529 markedly reduced microvessel density and increased tumour cell apoptosis in the tumours formed in mice inoculated with the lung cancer cells, SPC-A1 and A549, and the colon carcinoma cells, HCT116.

CONCLUSIONS AND IMPLICATIONS

YL529, an orally active multikinase inhibitor, shows therapeutic potential for solid tumours, and warrants further investigation as a possible anticancer agent.

A novel angiopoietin-2 selective fully human antibody with potent anti-tumoral and anti-angiogenic efficacy and superior side effect profile compared to Pan-Angiopoietin-1/-2 inhibitors

There is increasing experimental evidence for an important role of Angiopoietin-2 (Ang-2) in tumor angiogenesis and progression. In addition, Ang-2 is up-regulated in many cancer types and correlated with poor prognosis. To investigate the functional role of Ang-2 inhibition in tumor development and progression, we generated novel fully human antibodies that neutralize specifically the binding of Ang-2 to its receptor Tie2. The selected antibodies LC06 and LC08 recognize both rodent and human Ang-2 with high affinity, but LC06 shows a higher selectivity for Ang-2 over Ang-1 compared to LC08 which can be considered an Ang-2/Ang-1 cross-reactive antibody. Our data demonstrate that Ang-2 blockade results in potent tumor growth inhibition and pronounced tumor necrosis in subcutaneous and orthotopic tumor models. These effects are attended with a reduction of intratumoral microvessel density and tumor vessels characterized by fewer branches and increased pericyte coverage. Furthermore, anti-Ang-2 treatment strongly inhibits the dissemination of tumor cells to the lungs. Interestingly, in contrast to the Ang-2/Ang-1 cross-reactive antibody LC08 that leads to a regression of physiological vessels in the mouse trachea, the inhibition with the selective anti-Ang-2 antibody LC06 appears to be largely restricted to tumor vasculature without obvious effects on normal vasculature. Taken together, these data provide strong evidence for the selective Ang-2 antibody LC06 as promising new therapeutic agent for the treatment of various cancers.

[Colon cancer with portal vein tumor thrombosis-a case report and review of the literature]

Colon cancer with portal vein tumor thrombosis has a poor prognosis. However, little is known about the clinicopathological characteristics of these patients. In this study, we attempted to clarify the clinicopathological characteristics of such patients reported in the Japanese literature, including our own case. This case concerns a 48-year-old female patient diagnosed as having transverse colon cancer with severe portal vein tumor thrombosis. Despite curative resection, the patient was found to have multiple liver metastases six months later, and chemotherapy did not prove to be adequately effective; she died 18 months after surgery. A search of the relevant literature revealed 9 reports of similar patients. The patients consisted of 4 males and 6 synchronous cases, with a median age of 70 years. Portal vein tumor thrombosis was observed in 6 patients. While the portal vein was the most frequent site of thrombosis, other patients showed tumor thrombosis of the superior and inferior mesenteric veins. Despite curative resection, 3 patients eventually developed liver metastases after the operation. The median disease-free survival of the patients who had undergone curative resection was 300 days, and the overall median survival of the patients was 420 days. Thus, for the portal vein tumor thrombosis, we need to adopt adjuvant chemotherapy in consideration of a high risk for the liver metastases.

Antitumoral efficacy of the protease inhibitor gabexate mesilate in colon cancer cells harbouring KRAS, BRAF and PIK3CA mutations

The employment of anti-epidermal growth factor receptor (EGFR) antibodies represents a backbone of the therapeutic options for the treatment of metastatic colorectal cancer (mCRC). However, this therapy is poorly effective or ineffective in unselected patients. Mutations in KRAS, BRAF and PIK3CA genes have recently emerged as the best predictive factors of low/absent response to EGFR-targeted therapy. Due to the need for efficacious treatment options for mCRC patients bearing these mutations, in this short report we examined the antitumoral activity of the protease inhibitor gabexate mesilate, alone and in combination with the anti-EGFR monoclonal antibody cetuximab, in a panel of human CRC cell lines harbouring a different expression pattern of wild-type/mutated KRAS, BRAF and PIK3CA genes. Results obtained showed that gabexate mesilate significantly inhibited the growth, invasive potential and tumour-induced angiogenesis in all the CRC cells employed in this study (including those ones harbouring dual KRAS/PIK3CA or BRAF/PIK3CA mutation), while cetuximab affected these parameters only in CRC cells with KRAS, BRAF and PIK3CA wild-type. Notably, the antitumoral efficacy of gabexate mesilate and cetuximab in combination was found to be not superior than that observed with gabexate mesilate as single agent. Overall, these preliminary findings suggest that gabexate mesilate could represent a promising therapeutic option for mCRC patients, particularly for those harbouring KRAS, BRAF and PIK3CA mutations, either as mono-therapy or in addition to standard chemotherapy regimens. Further studies to better elucidate gabexate mesilate mechanism of action in CRC cells are therefore warranted.

A new apparatus and surgical technique for the dual perfusion of human tumor xenografts in situ in nude rats

We present a new perfusion system and surgical technique for simultaneous perfusion of 2 tissue-isolated human cancer xenografts in nude rats by using donor blood that preserves a continuous flow. Adult, athymic nude rats (Hsd:RH-Foxn1(rnu)) were implanted with HeLa human cervical or HT29 colon adenocarcinomas and grown as tissue-isolated xenografts. When tumors reached an estimated weight of 5 to 6 g, rats were prepared for perfusion with donor blood and arteriovenous measurements. The surgical procedure required approximately 20 min to complete for each tumor, and tumors were perfused for a period of 150 min. Results showed that tumor venous blood flow, glucose uptake, lactic acid release, O(2) uptake and CO(2) production, uptake of total fatty acid and linoleic acid and conversion to the mitogen 13-HODE, cAMP levels, and activation of several marker kinases were all well within the normal physiologic, metabolic, and signaling parameters characteristic of individually perfused xenografts. This new perfusion system and technique reduced procedure time by more than 50%. These findings demonstrate that 2 human tumors can be perfused simultaneously in situ or ex vivo by using either rodent or human blood and suggest that the system may also be adapted for use in the dual perfusion of other organs. Advantages of this dual perfusion technique include decreased anesthesia time, decreased surgical manipulation, and increased efficiency, thereby potentially reducing the numbers of laboratory animals required for scientific investigations.

MiR-145 directly targets p70S6K1 in cancer cells to inhibit tumor growth and angiogenesis

MiR-145 can regulate cell apoptosis, proliferation, neural development and stem cell differentiation. Previous studies indicate that miR-145 is downregulated in human colon cancer cells. However, the molecular mechanisms of miR-145 used to regulate colon carcinogenesis and angiogenesis remain to be clarified. Here, we show that the expression of miR-145 is downregulated in colon and ovarian cancer tissues and cell lines. MiR-145 inhibits p70S6K1 post-transcriptional expression by binding to its 3'-UTR. The angiogenic factors hypoxia-inducible factor 1 (HIF-1) and vascular endothelial growth factor (VEGF), which are downstream molecules of p70S6K1, are decreased by miR-145 overexpression. P70S6K1 rescues miR-145-suppressed HIF-1 and VEGF levels, tumorigenesis and tumor angiogenesis. Furthermore, the miR-145 level is inversely correlated with the amount of p70S6K1 protein in colon cancer tissues. Taken together, these studies suggest that miR-145 serves as a tumor suppressor which downregulates HIF-1 and VEGF expression by targeting p70S6K1, leading to the inhibition of tumor growth and angiogenesis. The miR-145 rescue could be a rationale for therapeutic applications in colon cancer in the future.

Global and local hard X-ray tomography of a centimeter-size tumor vessel tree

The visualization of the vascular network in tumors down to the smallest vessels requires high spatial resolution and reasonable contrast. Stained corrosion casts of the microvasculature network guarantee superior X-ray absorption contrast and highest reproduction fidelity. Tomography of a centimeter-size tumor, however, is unfeasible at the spatial resolution needed to reveal the smallest vessels. Therefore, local tomography has been performed to visualize the smallest capillaries within the region of interest. These three-dimensional data show the detailed morphology, but the reconstructed absorption coefficients obtained in local tomography differ substantially from the absorption coefficients retrieved from the less detailed global tomography data. This paper deals with the adaptation of local tomography data using the global data and considers two-parameter histogram matching of the radiographs, sinogram extension, and multi-parameter cupping correction. It is demonstrated that two-parameter histogram matching of the radiographs already provides reasonable agreement. The change of the lens in front of the detector's camera, however, significantly affects the obtained local X-ray absorption coefficients in the tomograms predominantly owing to the dissimilar point-spread functions of the two configurations used, and much less to the fact that one of the data sets was acquired in a local geometry.

Extracellular HSPA1A promotes the growth of hepatocarcinoma by augmenting tumor cell proliferation and apoptosis-resistance

Intracellular HSP70 has been implicated as a cytoprotective protein, whereas the effect of extracellular HSP70 on tumor cells has not been fully understood to date. Here we report that extracellular HSPA1A, a stress-inducible member of HSP70 family, could promote tumor growth. HSPA1A promoted the proliferation of H22 hepatocarcinoma cells through TLR2 and TLR4 signaling. The effect of HSPA1A was abolished by inhibiting NF-κB. HSPA1A also augmented the apoptosis-resistance of H22 cells by activating NF-κB, thus to promote the proliferation of H22 cells in presence of mitomycin C. Furthermore, the promoting effect of HSPA1A on tumor cell proliferation was existent after the removal of HSPA1A, which might involve HSPA1A-promoted upregulation of TLR4 expression in tumor cells and release of HMGB1 from tumor cells. These findings suggest that extracellular HSPA1A functions as endogenous ligand for TLR2 and TLR4 to facilitate tumor growth.

[Risk factors for recurrence of stage II colon cancer]

PURPOSES

This study was designed to clarify risk factors for the recurrence of stage II colon cancer in patients and to determine possible treatment options for postoperative adjuvant chemotherapy.

SUBJECTS AND METHODS

The subjects were 132 patients with stage II colon cancer who underwent surgery in this department from January 1998 to December 2007. Various high risk factors for recurrence and factors indicative of poor prognosis were examined (age, gender, site of tumor, maximum tumor diameter, invasion depth, histopathological classification, D number, ly, v, number of biopsied lymph nodes, preoperative tumor marker values and presence of postoperative adjuvant therapy).

RESULTS

The group with postoperative adjuvant therapy had a better prognosis than the others (p=0. 0168). Groups with an absence of postoperative adjuvant therapy (p=0. 041), presence of vessel involvement (p=0. 0127), and poorly-differentiated types (p=0. 027)were extracted in a multivariate analysis of risk factors for recurrence.

CONCLUSIONS

Postoperative adjuvant therapy was effective for stage II colon cancer. Vessel involvement and poorly-differentiated types were risk factors for recurrence of stage II colon cancer.

Mild elevation of body temperature reduces tumor interstitial fluid pressure and hypoxia and enhances efficacy of radiotherapy in murine tumor models

Human and rodent solid tumors often exhibit elevated interstitial fluid pressure (IFP). This condition is recognized as a prognostic indicator for reduced responses to therapy and decreased disease-free survival rate. In the present study, we tested whether induction of a thermoregulatory-mediated increase in tissue blood flow, induced by exposure of mice to mild environmental heat stress, could influence IFP and other vascular parameters within tumors. Using several murine tumor models, we found that heating results in a sustained reduction in tumor IFP correlating with increased tumor vascular perfusion (measured by fluorescent imaging of perfused vessels, laser Doppler flowmetry, and MRI) as well as a sustained reduction in tumor hypoxia. Furthermore, when radiation therapy was administered 24 hours postheating, we observed a significant improvement in efficacy that may be a result of the sustained reduction in tumor hypoxia. These data suggest, for the first time, that environmental manipulation of normal vasomotor function is capable of achieving therapeutically beneficial changes in IFP and microvascular function in the tumor microenvironment.

Interleukin-8 is associated with proliferation, migration, angiogenesis and chemosensitivity in vitro and in vivo in colon cancer cell line models

Interleukin-8 (IL-8), a chemokine with a defining CXC amino acid motif, is known to possess tumorigenic and proangiogenic properties. Overexpression of IL-8 has been detected in many human tumors, including colorectal cancer (CRC), and is associated with poor prognosis. The goal of our study was to determine the role of IL-8 overexpression in CRC cells in vitro and in vivo. We stably transfected the IL-8 cDNA into two human colon cancer cell lines, HCT116 and Caco2, and selected IL-8-secreting transfectants. Real-time RT-PCR confirmed that IL-8 mRNA was overexpressed in IL-8 transfectants with 45- to 85-fold higher than parental cells. The IL-8-transfected clones secreted 19- to 28-fold more IL-8 protein than control and parental cells as detected by ELISA. The IL-8 transfectants demonstrated increased cellular proliferation, cell migration and invasion based on functional assays. Growth inhibition studies showed that IL-8 overexpression lead to a significant resistance to oxaliplatin (p < 0.0001). Inhibition of IL-8 overexpression with small interfering RNA reversed the observed increases in tumorigenic functions and oxaliplatin resistance, suggesting that IL-8 not only provides a proliferative advantage but also promotes the metastatic potential of colon cancer cells. Using a tumor xenograft model, IL-8-expressing cells formed significantly larger tumors than the control cells with increased microvessel density. Together, these findings indicate that overexpression of IL-8 promotes tumor growth, metastasis, chemoresistance and angiogenesis, implying IL-8 to be an important therapeutic target in CRC.

Magnetic resonance and fluorescence-protein imaging of the anti-angiogenic and anti-tumor efficacy of selenium in an orthotopic model of human colon cancer

Tumor progression and angiogenesis are intimately related. To understand the interrelationship between these two processes, real-time imaging can make a major contribution. In this report, fluorescent protein imaging (FPI) and magnetic resonance imaging (MRI) were utilized to demonstrate the effects of selenium on tumor progression and angiogenesis in an orthotopic model of human colon cancer. GEO (well-differentiated human colon carcinoma) cells transfected with green fluorescent protein (GFP) were implanted orthotopically into the colon of athymic nude mice. Beginning at five days post implantation, whole-body FPI was performed to monitor tumor growth in vivo. Upon successful visualization of tumor growth by FPI, animals were randomly assigned to either a control group or a treatment group. Treatment consisted of daily oral administration of the organoselenium compound, methyl-selenocysteine (MSC; 0.2 mg/day × five weeks). Dynamic contrast-enhanced MRI was performed to examine the change in tumor blood volume following treatment. CD31 immunostaining of tumor sections was also performed to quantify microvessel density (MVD). While T1- and T2-weighted MRI provided adequate contrast and volumetric assessment of GEO tumor growth, GFP imaging allowed for high-throughput visualization of tumor progression in vivo. Selenium treatment resulted in a significant reduction in blood volume and microvessel density of GEO tumors. A significant inhibition of tumor growth was also observed in selenium-treated animals compared to untreated control animals. Together, these results highlight the usefulness of multimodal imaging approaches to demonstrate antitumor and anti-angiogenesis efficacy and the promise of selenium treatment of colon cancer.

Adnectin CT-322 inhibits tumor growth and affects microvascular architecture and function in Colo205 tumor xenografts

Antiangiogenesis has become a promising pillar in modern cancer therapy. This study investigates the antiangiogenic effects of the PEGylated Adnectin™, CT-322, in a murine Colo-205 xenograft tumor model. CT-322 specifically binds to and blocks vascular endothelial growth factor receptor (VEGFR-2). Adnectins are a novel class of targeted biologics engineered from the 10th domain of human fibronectin. CT-322 treated tumors exhibited a significant reduction in tumor growth of 69%, a 2.8 times lower tumor surface area and fewer necrotic areas. Control tumors showed a 2.36-fold higher microvessel density (MVD) and a 2.42 times higher vessel volume in corrosion casts. The vascular architecture in CT-322-treated tumors was characterized by a strong normalization of vasculature. This was quantified in corrosion casts of CT-322 treated tumors in which the intervascular distance (a reciprocal parameter indicative of vessel density) and the distance between two consecutive branchings were assessed, with these distances being 2.21 times and 2.37 times greater than in controls, respectively. Fluorescence molecular tomography (FMT) equally affirmed the inhibitory effects of CT-322 on tumor vasculature as indicated by a 60% reduction of the vascular probe, AngioSense, accumulating in tumor tissue, as a measurement of vascular permeability. Moreover, AngioSense accumulation was reduced as early as 24 h after starting treatment. The sum of these effects on tumor vasculature illustrates the anti-angiogenic mechanism underlying the antitumor activity of CT-322 and provides support for further evaluation of this Adnectin in combinatorial strategies with standard of care therapies.

Percutaneous ultrasonography-guided core needle biopsy of gastrointestinal lesions: what's its actual role in clinical practice? A retrospective study for safety and effectiveness

PURPOSE

Endoscopic biopsy is commonly performed to obtain a pathological diagnosis of gastrointestinal (GI) lesions. When the lesions are submucosal, subserosal, or exophytic, endoscopic biopsy is often unsuccessful, and endoscopic ultrasound (EUS)-guided biopsy is considered the procedure of choice in these cases. Nevertheless, in some patients both endoscopic and EUS-guided biopsy are not indicated, or yield inconclusive cyto-histological results. The aim of this study was to assess the efficacy and safety of percutaneous ultrasonography (US)-guided biopsy of GI wall lesions, and to define its actual role in clinical practice.

MATERIALS AND METHODS

A retrospective study was conducted on 45 consecutive US-guided biopsies of GI lesions. All biopsies were performed in patients unsuitable for endoscopic or EUS-guided biopsy, or with lesions inaccessible to endoscopic techniques, or with inconclusive results from endoscopic or EUS-guided biopsy. Biopsies were performed with an 18 or 20-gauge Tru-cut needle under US guidance. Biopsy results were compared with the final diagnosis that was based on surgical pathological findings or clinical instrumental follow-up of at least 20 months. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall accuracy, and complication rate of the procedure were calculated.

RESULTS

One biopsy specimen (2.2 %) was inadequate for cyto-histologic examination. In the remaining 44 cases, US-guided biopsy correctly identified 39 / 40 (97.5 %) malignant lesions, and 4 / 4 (100 %) benign lesions. One case resulted in a false negative (2.2 %). The sensitivity, specificity, PPV, NPV, and overall diagnostic accuracy were 97.5 %, 100 %, 100 %, 80 % and 97.7 %, respectively. Including also the inadequate specimen into the analysis, they were 95.1 %, 100 %, 100 %, 66.7 % and 95.6 %, respectively. No procedure-related complications were observed. In ten cases (22.2 %), US-guided biopsy results made it possible to avoid unnecessary surgical exploration.

CONCLUSION

Percutaneous US-guided core biopsy of GI wall lesions is an accurate and safe technique that makes it possible in select cases to obtain a correct pathological diagnosis and prevent unnecessary surgical exploration. Although it has been replaced by EUS-guided biopsy as the procedure of choice to sample submucosal or subserosal GI lesions, US-guided biopsy can still play a useful role in the diagnostic workup of GI lesions when endoscopy or EUS is unsuccessful for various reasons or yields inconclusive cyto-histological results.

Lack of functioning lymphatics and accumulation of tissue fluid/lymph in interstitial "lakes" in colon cancer tissue

There is controversy as to whether intratumoral or peritumoral lymphatics play a dominant role in the metastatic process. The knowledge of how and where exactly tumor cells enter lymphatics is important for therapeutic targeting either the tumor core or peritumoral tissue with drugs or radiation. The basic questions remain: what is the morphological structure of intra- and peritumoral interstitium and lymphatics; what is their hydraulic conductivity?; and do these local physical conditions allow detached tumor cells to migrate to lymphatics? Identification of lymphatics has been based on immunohistochemical staining of lymphatic endothelial cells. This method does not, however, show the tissue fluid filled interstitial space and the shape of minute lymphatic vessels in tumors. We visualized the interstitial space and lymphatics in the central and peripheral regions of tumors using our original method of color stereoscopic lymphography in translucent tissue fragments and simultaneously with immunohistochemical staining of lymphatic and blood endothelial cells. The density of open and compressed lymphatic and blood vessels was measured in the intratumoral "hot spots" and at tumor edge. Moreover, the intratumoral tissue hydraulic conductivity was measured to define force necessary for propelling tissue fluid to peritumoral lymphatics. We found very few rudimentary minor blind lymphatics in the tumor core and numerous minor fluid "lakes" in the interstitium with no visible connection to the peritumoral lymphatics. Lining of "lakes" did not express molecular markers specific for lymphatic endothelial cells. Ninety-five percent of structures of what looked like lymphatics had compressed lumen and the hydraulic conductivity was 3 powers of magnitude lower than in the adjacent non-tumoral tissue. It can be concluded that lack of functioning lymphatics in tumor foci manifested by accumulation of tissue fluid in "lakes," low fluid conductivity and compression of lymphatics by tumor cells, and proliferating connective tissue may hamper escape of tumor cells. The most favorable site of entry of tumor cells to lymphatics seems to be the interface of the tumor and surrounding tissue with open lymphatics.

Angiotensin II-induced hypertension enhanced therapeutic efficacy of liposomal doxorubicin in tumor-bearing mice

In this study, we investigated whether the therapeutic efficacy of liposomal doxorubicin (DXR-SL) could be enhanced by angiotensin II (AT)-induced hypertension. AT-induced hypertension increased the volume of tumor blood flow in mice bearing a poorly vascularized Lewis lung carcinoma (LLC) tumor, but only slightly in mice bearing a well-vascularized colon carcinoma Colon 26 (C26) tumor. In therapeutic efficacy, AT-induced hypertension enhanced the antitumor activity of DXR-SL in mice bearing LLC and C26 tumors. Localization of DXR-SL after injection by AT-induced hypertension was observed outside tumor blood vessels in LLC and C26 tumors, but within them under the normotension. From these findings, AT-induced hypertension had potential to improve the delivery of DXR-SL to both well- and poorly vascularized solid tumors.

[Two cases of unstable angina in patients treated with bevacizumab]

Adverse events associated with bevacizumab (BV) were haemorrhage, impaired wound healing and arterial thromboembolism. We report 2 patients with colorectal cancer who underwent percutaneous coronary intervention (PCI) for unstable angina soon after administration of chemotherapy including BV. CASE 1: A 74-year-old male with rectal cancer and simultaneous liver metastases was admitted to our hospital for unstable angina. Before admission he had received 4 courses of chemotherapy including BV. He had no coronary risk factors besides old age. Since coronary angiography (CAG) revealed significant stenosis in the mid-left circumflex coronary artery, PCI with a coronary stent was performed without any complications. CASE 2: A 67-year-old male with colon cancer and liver and lung metastases was referred to our Dept. of Internal Medicine for unstable angina. Before referral, he had undergone 28 courses of chemotherapy including BV. He had a history of familial hyperlipidemia and smoking. Since CAG revealed significant stenoses in the proximal left anterior descending coronary artery, PCI with coronary stents was performed without any complications. These 2 patients had no angina after PCI. PCI with coronary stent was safely performed in this patient with unstable angina soon after administration of chemotherapy including BV.

Antitumor activity of an adenovirus harboring human IL-24 in colon cancer

Data have increasingly shown that melanoma differentiation associated gene-7 (Mda-7/IL-24) has growth suppression activity and can induce apoptosis in many tumor cells, but to our knowledge there have been few studies about its role in colon cancer. We examined its anti-cancer effect on colon cancer. We constructed a recombinant replication-deficient adenovirus carrying human melanoma differentiation associated gene-7 (Ad-IL-24) and examined its apoptosis-inducing efficacy on the colon cancer HT-29 cell line and on an oxaliplatin-resistant cell line HT-29/oxa, using a combination of flow cytometry, growth suppressive activity by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and xenografts. Furthermore, we tested the suppression activity of Mda-7/IL-24 on vascular endothelial growth factor (VEGF) and microvessel density (MVD), as well as the inductive effect on expression of the growth arrest and DNA damage gene (GADD) in xenograft tumors by immunohistochemistry. Melanoma differentiation associated gene-7 can inhibit the growth of colon cancer cell lines and induced apoptosis in about (5.6±0.3)% of HT-29 cells (P<0.05). Xenograft growth was retarded in vivo in mice treated with melanoma differentiation associated gene-7, but the tumor proliferation rate for this group was not significantly different in comparison to controls (P>0.05). Furthermore, melanoma differentiation associated gene-7 induced expression of a growth arrest and DNA damage (GADD) gene and reduced the expression of both VEGF and MVD in xenograft tumors. This study supports a potential therapeutic effect for melanoma differentiation associated gene-7 on colon cancer.

Complementary actions of inhibitors of angiopoietin-2 and VEGF on tumor angiogenesis and growth

Inhibition of angiopoietin-2 (Ang2) can slow tumor growth, but the underlying mechanism is not fully understood. Because Ang2 is expressed in growing blood vessels and promotes angiogenesis driven by vascular endothelial growth factor (VEGF), we asked whether the antitumor effect of Ang2 inhibition results from reduced sprouting angiogenesis and whether the effect is augmented by inhibition of VEGF from tumor cells. Using Colo205 human colon carcinomas in nude mice as a model, we found that selective inhibition of Ang2 by the peptide-Fc fusion protein L1-7(N) reduced the number of vascular sprouts by 46% and tumor growth by 62% over 26 days. Strikingly, when the Ang2 inhibitor was combined with a function-blocking anti-VEGF antibody, the number of sprouts was reduced by 82%, tumor vascularity was reduced by 67%, and tumor growth slowed by 91% compared with controls. The reduction in tumor growth was accompanied by decreased cell proliferation and increased apoptosis. We conclude that inhibition of Ang2 slows tumor growth by limiting the expansion of the tumor vasculature by sprouting angiogenesis, in a manner that is complemented by concurrent inhibition of VEGF and leads to reduced proliferation and increased apoptosis of tumor cells.

[A case of advanced ascending colon cancer, curatively resected after complete response in left supraclavicular and paraaortic lymph nodes and liver metastases to FOLFOX4 therapy]

We report a resected case of ascending colon cancer with left supraclavicular and paraaortic lymph nodes and liver metastases which completely responded in terms of metastases but not the primary tumor to FOLFOX4 therapy. A 62-year-old woman with epigastric discomfort was initially diagnosed as malignant lymphoma by FDG-PET with abnormal accumulation at left supraclavicular and paraaortic lesions. Pathological examination of the supraclavicular lymph nodes showed undifferentiated adenocarcinoma, and ascending colon cancer was detected by colonoscopy which was a mixture of various types of differentiation. FOLFOX4 therapy was effective for metastatic lesions but colon tumor did not regress and was accompanied by abdominal pain. Macroscopically, a curative right hemicolectomy was performed, and microscopic examination revealed that the tumor had become a mass of undifferentiated cancer cells. Thus, the present case demonstrates the dedifferentiation of colon cancer during chemotherapy.

Impact of tumor cell VEGF expression on the in vivo efficacy of vandetanib (ZACTIMA; ZD6474)

VEGF is the key player in tumor angiogenesis. In the current study, the impact of VEGF expression on the response of tumors to the VEGFR2 associated tyrosine kinase inhibitor vandetanib was evaluated.

MATERIALS AND METHODS

Human colon carcinoma (HT29) and murine squamous carcinoma (SCCVII) clonal cell lines expressing varying levels of VEGF were established and their response to vandetanib was assessed in tissue culture and as solid tumors.

RESULTS

Vandetanib treatment had no effect on tumor cell clonogenic cell survival in vitro but doses >or=10 nM significantly reduced endothelial cell migration. In vivo, tumors derived from cell clones expressing high levels of VEGF displayed significantly enhanced angiogenesis and more aggressive growth. An intradermal angiogenesis assay was used to demonstrate that a 4-day treatment with vandetanib (50 mg/kg/day) was able to significantly inhibit blood vessel growth induced by both parental and high VEGF-expressing tumor cell clones. In the HT29 tumor model, treatment response to vandetanib (50 mg/kg/day, Monday-Friday for 2 weeks) was greatest in xenografts derived from the highest VEGF-expressing cell clones. A similar trend was noted in the SCCVII tumor model. The present findings indicate that vandetanib therapy effectively counteracted the aggressive feature of tumor growth resulting from VEGF over-expressing tumor cells and suggest that such tumors may be particularly well suited for anti-VEGF interventions.