Correlation between CD105 expression and postoperative recurrence and metastasis of hepatocellular carcinoma

Recent Updates on Viral Oncogenesis: Available Preventive and Therapeutic Entities

Human viral oncogenesis is a complex phenomenon and a major contributor to the global cancer burden. Several recent findings revealed cellular and molecular pathways that promote the development and initiation of malignancy when viruses cause an infection. Even, antiviral treatment has become an approach to eliminate the viral infections and prevent the activation of oncogenesis. Therefore, for a better understanding, the molecular pathogenesis of various oncogenic viruses like, hepatitis virus, human immunodeficiency viral (HIV), human papillomavirus (HPV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV), could be explored, especially, to expand many potent antivirals that may escalate the apoptosis of infected malignant cells while sparing normal and healthy ones. Moreover, contemporary therapies, such as engineered antibodies antiviral agents targeting signaling pathways and cell biomarkers, could inhibit viral oncogenesis. This review elaborates the recent advancements in both natural and synthetic antivirals to control viral oncogenesis. The study also highlights the challenges and future perspectives of using antivirals in viral oncogenesis.

PD-1 blocking strategy for enhancing the anti-tumor effect of CAR T cells targeted CD105

Purpos

CD105 has become a promising target of immunotherapy development for highly specific expression on the neovascular surface of most types of tumor cells. In previous studies, we constructed a CAR T cell (CD105 CAR T cell) and observed significant antitumor activity. In this study, we optimized the structure of CD105 CAR to increase PD-1 antibody secretion function (CD105 × PD-1 CAR T cells).

Methods

we tested whether Increased PD-1 antibody secretion with CAR T cells targeted CD105 could promote in vitro proliferation, proinflammatory cytokine production and cytotoxicity,or not. For the in vivo experiments, we constructed a subcutaneously transplanted tumor model and placed it in NOD/SCID mice to verify the anti-tumor effect of this therapy.

Results

Our data showed that the PD-1 antibody secreted by CD105 × PD-1 CAR T cells could specifically bind to the PD-1 receptor of T cells then blocked the PD-1/PD-L-1 signaling pathway, thus enhancing the activation and proliferation of CAR T cells. After incubation of CD105 × PD-1 CAR T cells with HepG2 as a hepatocellular carcinoma cell line expressing CD105, the results showed that CD105 × PD-1 CAR T cells increased the expression levels of CD69 and CD62L, enhanced the proliferation capacity of CAR T cells, and secreted more IL-2, TNF-α and IFN-γ than CD105 CAR T cells.

Conclusion

These data showed that CD105 × PD-1 CAR T cells was specifically killing tumor cells in vitro and in vivo. Our findings may therefore provide a promising new strategy for the improvement of CAR T therapy for solid tumors.

Intravoxel incoherent motion imaging used to assess tumor microvascular changes after transarterial chemoembolization in a rabbit VX2 liver tumor model

Purpose

To evaluate the correlation between microvascular density (MVD) and intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) parameters and the effect of glycolytic flux after transarterial chemoembolization (TACE) in a rabbit VX2 liver tumor.

Materials and methods

VX2 liver tumor allografts in 15 New Zealand white rabbits were treated with sterile saline (control group, n = 5) or lipiodol-doxorubicin emulsion (experimental group, n = 10). MRI was performed 2 weeks after the procedure to evaluate IVIM parameters, including apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (PF). All animal samples were taken of the tumor and surrounding liver. Immunostaining for CD31, CD34, CD105, and VEGF was used to evaluate MVD. The protein expression of Glut4, HK2, PKM2, LDHA, and MCT1 was determined using western blotting. Pearson correlation tests were used to analyze the relationship between MVD and IVIM parameters.

Results

D* value in the peritumoral region was negatively correlated with CD34 (r = -0.71, P = 0.01). PF value positively correlated with CD34 (r = 0.68, P = 0.015), CD105 (r = 0.76, P = 0.004) and VEGF (r = 0.72, P = 0.008) in the peritumoral region. Glut4, HK2, PKM2, and MCT1 in the peritumoral regions were higher in the experimental group than in the control group (all P < 0.05).

Conclusion

IVIM parameters were correlated with MVD in the intratumoral and peritumoral regions after TACE in a rabbit liver tumor model. The angiogenesis reflected by MVD may be related to changes of glycolytic flux.

Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment

Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms.

CD105: tumor diagnosis, prognostic marker and future tumor therapeutic target

Cancer is one of the diseases with the highest morbidity and mortality rates worldwide, and its therapeutic options are inadequate. The endothelial glycoprotein, also known as CD105, is a type I transmembrane glycoprotein located on the surface of the cell membranes and it is one of the transforming growth factor-β (TGF-β) receptor complexes. It regulates the responses associated with binding to transforming growth factor β1 egg (Activin-A), bone morphogenetic protein 2 (BMP-2), and bone morphogenetic protein 7 (BMP-7). Additionally, it is involved in the regulation of angiogenesis. This glycoprotein is indispensable in the treatment of tumor angiogenesis, and it also plays a leading role in tumor angiogenesis therapy. Therefore, CD105 is considered to be a novel therapeutic target. In this study, we explored the significance of CD105 in the diagnosis, treatment and prognosis of various tumors, and provided evidence for the effect and mechanism of CD105 on tumors.

Recent advances in systemic therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and lethal malignant tumors in the world. Therapeutic options for advanced HCC are limited. Systemic treatment, especially with conventional cytotoxic drugs, is usually ineffective. For more than a decade, sorafenib has been the only systemic drug that has been proven to be clinically effective for treating advanced HCC. However, over the past three years, the rapid progress of molecular targeted therapies has dramatically changed the treatment landscape for advanced HCC. Immune checkpoint therapies are now being incorporated into HCC therapies, and their combination with molecular targeted therapy is emerging as a tool to enhance the immune response. In this review, we summarize the development and progress of molecular targeted agents and immunotherapies in HCC.

Regression of Hepatic Fibrosis and Evolution of Cirrhosis: A Concise Review

Fibrosis is not a unidirectional, linear process, but a dynamic one resulting from an interplay of fibrogenesis and fibrolysis depending on the extent and severity of a biologic insult, or lack thereof. Regression of fibrosis has been documented best in patients treated with phlebotomies for hemochromatosis, and after successful suppression and eradication of chronic hepatitis B and C infections. This evidence mandates a reconsideration of the term "cirrhosis," which implies an inevitable progression towards liver failure. Furthermore, it also necessitates a staging system that acknowledges the bidirectional nature of evolution of fibrosis, and has the ability to predict if the disease process is progressing or regressing. The Beijing classification attempts to fill this gap in contemporary practice. It is based on microscopic features termed "the hepatic repair complex," defined originally by Wanless and colleagues. The elements of the hepatic repair complex represent the 3 processes of fragmentation and regression of scar, vascular remodeling (resolution), and parenchymal regeneration. However, regression of fibrosis does not imply resolution of cirrhosis, which is more than just a stage of fibrosis. So far, there is little to no evidence to suggest that large regions of parenchymal extinction can be repopulated by regenerating hepatocytes. Similarly, the vascular lesions of cirrhosis persist, and there is no evidence of complete return to normal microcirculation in cirrhotic livers. In addition, the risk of hepatocellular carcinoma is higher compared with the general population and these patients need continued screening and surveillance.

Screening and identification of angiogenesis-related genes as potential novel prognostic biomarkers of hepatocellular carcinoma through bioinformatics analysis

Hepatocellular carcinoma (HCC) is a malignant tumor with high morbidity and mortality, which makes the prognostic prediction challenging. Angiogenesis appears to be of critical importance in the progression and metastasis of HCC. Some of the angiogenesis-related genes promote this process, while other anti-angiogenesis genes suppress tumor growth and metastasis. Therefore, the comprehensive prognostic value of multiple angiogenesis-related genes in HCC needs to be further clarified. In this study, the mRNA expression profile of HCC patients and the corresponding clinical data were acquired from multiple public databases. Univariate Cox regression analysis was utilized to screen out differentially expressed angiogenesis-related genes with prognostic value. A multigene signature was established with the least absolute shrinkage and selection operator Cox regression in the Cancer Genome Atlas cohort, and validated through an independent cohort. The results suggested that a total of 16 differentially expressed genes (DEGs) were associated with overall survival (OS) and a 7-gene signature was constructed. The risk score of each patient was calculated using this signature, the median value of which was used to divide these patients into a high-risk group and a low-risk group. Compared with the low-risk group, the patients in the high-risk group had a poor prognosis. The risk score was an independent predictor for OS through multivariate Cox regression analysis. Then, unsupervised learning was used to verify the validity of this 7-gene signature. A nomogram by further integrating clinical information and the prognostic signature was utilized to predict prognostic risk and individual OS. Functional enrichment analyses demonstrated that these DEGs were enriched in the pathways of cell proliferation and mitosis, and the immune cell infiltration was significantly different between the two risk groups. In summary, a novel angiogenesis-related genes signature could be used to predict the prognosis of HCC and for targeted therapy.

Clinical Results and Biomarker Analyses of Axitinib and TRC105 versus Axitinib Alone in Patients with Advanced or Metastatic Renal Cell Carcinoma (TRAXAR)

LESSONS LEARNED

The combination of carotuximab with axitinib did not provide a benefit over axitinib monotherapy in patients with metastatic clear cell renal cell carcinoma who had previously progressed on one or more vascular endothelial growth factor (VEGF)-targeted therapies. Exploratory evaluation of pretreatment circulating biomarkers suggested the combination might benefit patients who have low baseline VEGF levels.

BACKGROUND

Endoglin is an angiogenic receptor expressed on proliferating tumor vessels and renal cell carcinoma (RCC) stem cells that is implicated as a mechanism of resistance to vascular endothelial growth factor receptor (VEGFR) inhibitors. This study evaluated an antiendoglin monoclonal antibody (carotuximab, TRC105) combined with axitinib in patients with advanced or metastatic clear cell renal cell carcinoma (mccRCC) who had progressed following one or more prior VEGF inhibitors.

METHODS

TRAXAR was a multicenter, international randomized 1:1 (stratified by ECOG, 0 vs. 1), phase II study of carotuximab combined with axitinib versus axitinib alone in mccRCC patients who had progressed following one or more prior VEGF inhibitors. The primary endpoint was progression-free survival (PFS) assessed by independent central review (ICR) per RECIST 1.1 RESULTS: A total of 150 patients were randomized. The combination therapy resulted in shorter median PFS by RECIST 1.1 than axitinib monotherapy (6.7 vs. 11.4 months). The combination was tolerated similarly to axitinib monotherapy, and there were no treatment related deaths. Exploratory evaluation of pretreatment circulating biomarkers suggested the combination might benefit patients who have low baseline VEGF levels.

CONCLUSION

The combination of carotuximab with axitinib did not demonstrate additional efficacy over single agent axitinib in patients with mccRCC who progressed following one or more prior VEGF inhibitor treatment.

The Role of Endoglin in Hepatocellular Carcinoma

Endoglin (CD105) is a type-1 integral transmembrane glycoprotein and coreceptor for transforming growth factor-β (TGF-β) ligands. The endoglin/TGF-β signaling pathway regulates hemostasis, cell proliferation/migration, extracellular matrix (ECM) synthesis and angiogenesis. Angiogenesis contributes to early progression, invasion, postoperative recurrence, and metastasis in hepatocellular carcinoma (HCC), one of the most widespread malignancies globally. Endoglin is overexpressed in newly formed HCC microvessels. It increases microvessel density in cirrhotic and regenerative HCC nodules. In addition, circulating endoglin is present in HCC patients, suggesting potential for use as a diagnostic or prognostic factor. HCC angiogenesis is dynamic and endoglin expression varies by stage. TRC105 (carotuximab) is an antibody against endoglin, and three of its clinical trials were related to liver diseases. A partial response was achieved when combining TRC105 with sorafenib. Although antiangiogenic therapy still carries some risks, combination therapy with endoglin inhibitors or other targeted therapies holds promise.

Endoglin Expression and Microvessel Density as Prognostic Factors in Pediatric Rhabdomyosarcoma

(1) Background: The study proposed to analyze microvessel density (MVD) in rhabdomyosarcoma (RMS) based on the expression of angiogenesis markers and define its prognostic role in this group of patients. (2) Methods: The study included forty-nine pediatric patients diagnosed with RMS. Tumor tissue expression of CD31, CD34, and CD105 was analyzed. MVD was calculated and correlated with clinical RMS prognostic parameters. (3) Results: CD31, CD34, and CD105 are expressed in all RMS cases. MVD/CD105 was significantly higher in the RMS group than in the control group. The mean and median values of MVD/CD105 in RMS were lower than MVD/CD31 and MVD/CD34. MVD/CD105 was significantly higher in patients with alveolar RMS and those with metastatic disease. Patients with higher levels of MVD/CD105 had a higher risk of death (HR = 1.009). (4) Conclusion: CD105 is a relevant angiogenesis marker in pediatric RMS, and MVD/CD105 is an independent risk factor of short overall survival in children with RMS.

Evaluation of Intra-Tumoral Vascularization in Hepatocellular Carcinomas

Intratumoral neovascularization has intricate effects on tumor growth, metastasis, and treatment. Over the last 30 years, Microvessel density (MVD) has been the standard method for laboratory and clinical evaluation of angiogenesis. Hepatocellular carcinoma (HCC) is a typical hypervascularized tumor, and the predictive value of MVD for prognosis is still controversial. According to previous viewpoints, this has been attributed to the determination of hotspot, counting methods, vascular endothelial markers, and different definitions of high and low vascular density; however, the heterogeneity of tumor angiogenesis patterns should be factored. The breakthroughs in artificial intelligence and algorithm can improve the objectivity and repeatability of MVD measurement, thus saving a lot of manpower. Presently, anti-angiogenesis therapy is the only effective systematic treatment for liver cancer, and the use of imaging technology-assisted MVD measurement is expected to be a reliable index for evaluating the curative effect. MVD in multinodular hepatocellular carcinoma represents a subject area with huge understudied potential, and exploring it might advance our understanding of tumor heterogeneity.

Hepatitis C Virus and Hepatocellular Carcinoma: When the Host Loses Its Grip

Chronic infection with hepatitis C virus (HCV) is a major cause of hepatocellular carcinoma (HCC). Novel treatments with direct-acting antivirals achieve high rates of sustained virologic response; however, the HCC risk remains elevated in cured patients, especially those with advanced liver disease. Long-term HCV infection causes a persistent and accumulating damage of the liver due to a combination of direct and indirect pro-oncogenic mechanisms. This review describes the processes involved in virus-induced disease progression by viral proteins, derailed signaling, immunity, and persistent epigenetic deregulation, which may be instrumental to develop urgently needed prognostic biomarkers and as targets for novel chemopreventive therapies.

Inhibition of Endoglin Exerts Antitumor Effects through the Regulation of Non-Smad TGF-β Signaling in Angiosarcoma

Angiosarcoma is a rare malignant tumor derived from endothelial cells, and its prognosis is poor because advanced angiosarcoma is often resistant to taxane therapy. Endoglin (CD105) acts as a coreceptor for TGF-β signaling and is overexpressed in tumor-associated endothelial cells and enhances tumor angiogenesis. Numerous clinical trials are testing the effectiveness of anti-endoglin antibodies in various types of malignancies. Here, we investigated the role of endoglin in the pathogenesis of angiosarcoma and whether endoglin inhibition results in antitumor activity. Endoglin was overexpressed in angiosarcoma, and its inhibition was effective in promoting apoptosis and the suppression of migration, invasion, tube formation, and Warburg effect in angiosarcoma cells. Knockdown of endoglin activated caspase 3/7 that is essential for apoptosis, reduced survivin levels, and decreased paxillin and vascular endothelial cadherin phosphorylation and matrix metalloproteinase 2 and matrix metalloproteinase 9 activities in angiosarcoma cells. Although endoglin is a coreceptor that regulates TGF-β signaling, the antitumor effect of endoglin in angiosarcoma was not based on Smad signaling regulation but on non-Smad TGF-β signaling. Taken together, these results indicated that endoglin could be a novel therapeutic target for angiosarcoma.

Role of Endoglin (CD105) in the Progression of Hepatocellular Carcinoma and Anti-Angiogenic Therapy

The liver is perfused by both arterial and venous blood, with a resulting abnormal microenvironment selecting for more-aggressive malignancies. Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, the sixth most common cancer globally, and the third leading cause of cancer-related mortality worldwide. HCC is characterized by its hypervascularization. Improving the efficiency of anti-angiogenic treatment and mitigation of anti-angiogenic drug resistance are the top priorities in the development of non-surgical HCC therapies. Endoglin (CD105), a transmembrane glycoprotein, is one of the transforming growth factor β (TGF-β) co-receptors. Involvement of that protein in angiogenesis of solid tumours is well documented. Endoglin is a marker of activated endothelial cells (ECs), and is preferentially expressed in the angiogenic endothelium of solid tumours, including HCC. HCC is associated with changes in CD105-positive ECs within and around the tumour. The large spectrum of endoglin effects in the liver is cell-type- and HCC- stage-specific. High expression of endoglin in non-tumour tissue suggests that this microenvironment might play an especially important role in the progression of HCC. Evaluation of tissue expression, as well as serum concentrations of this glycoprotein in HCC, tends to confirm its role as an important biomarker in HCC diagnosis and prognosis. The role of endoglin in liver fibrosis and HCC progression also makes it an attractive therapeutic target. Despite these facts, the exact molecular mechanisms of endoglin functioning in hepatocarcinogenesis are still poorly understood. This review summarizes the current data concerning the role and signalling pathways of endoglin in hepatocellular carcinoma development and progression, and provides an overview of the strategies available for a specific targeting of CD105 in anti-angiogenic therapy in HCC.

Endoglin-targeted contrast-enhanced ultrasound imaging in hepatoblastoma xenografts

Angiogenesis is required for the growth of hepatoblastoma (HB). In the present study, an ultrasonic contrast agent, microbubbles (MB), was combined with an endoglin antibody, and then injected into nude mice with HB. This was conducted to detect specific binding to microvessels via non-linear harmonic imaging for tumor angiogenesis assessment. In addition, endoglin expression in experimental animals was measured using western blotting, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. In vitro, human umbilical vein endothelial cells (HUVECs) were co-cultured with conditioned media collected from HepG2 cells. Western blotting and reverse transcription-quantitative PCR was performed to detect the changes of endoglin expression. In targeted ultrasound imaging, it was determined that the differential targeted enhancement of MB_endoglin was significantly higher than that of MB_isotype. Over expression of endoglin was identified in the tumor of experimental nude mice; however, it was not present in the liver of the mice. Endoglin expression in HUVECs was significantly increased by co-culture with the conditioned media of HepG2 cells; therefore, the results suggest that endoglin is upregulated in angiogenic vessels in the HepG2 cell xenografts in nude mice. Thus, endoglin-targeted ultrasound imaging is presented as a potential approach for the diagnosis of liver carcinoma.

Evaluation of Endoglin (CD105) expression in pediatric rhabdomyosarcoma

BACKGROUND

The Intratumoral Microvessel Density (IMVD) is commonly used to quantify tumoral vascularization and is usually assessed by pan-endothelial markers, such as CD31. Endoglin (CD105) is a protein predominantly expressed in proliferating endothelium and the IMVD determined by this marker measures specifically the neovascularization. In this study, we investigated the CD105 expression in pediatric rhabdomyosarcoma and assessed the neovascularization by using the angiogenic ratio IMVD-CD105 to IMVD-CD31.

METHODS

Paraffin-embedded archival tumor specimens were selected from 65 pediatric patients affected by rhabdomyosarcoma. The expression levels of CD105, CD31 and Vascular Endothelial Growth Factor (VEGF) were investigated in 30 cases (18 embryonal and 12 alveolar) available for this study. The IMVD-CD105 to IMVD-CD31 expression ratio was correlated with clinical and pathologic features of these patients.

RESULTS

We found a specific expression of endoglin (CD105) in endothelial cells of all the rhabdomyosarcoma specimens analyzed. We observed a significant positive correlation between the IMVD individually measured by CD105 and CD31. The CD105/CD31 expression ratio was significantly higher in patients with lower survival and embryonal histology. Indeed, patients with a CD105/CD31 expression ratio < 1.3 had a significantly increased OS (88%, 95%CI, 60%-97%) compared to patients with higher values (40%, 95%CI, 12%-67%). We did not find any statistical correlation among VEGF and EFS, OS and CD105/CD31 expression ratio.

CONCLUSION

CD105 is expressed on endothelial cells of rhabdomyosarcoma and represent a useful tool to quantify neovascularization in this tumor. If confirmed by further studies, these results will indicate that CD105 is a potential target for combined therapies in rhabdomyosarcoma.

Phase I and Preliminary Phase II Study of TRC105 in Combination with Sorafenib in Hepatocellular Carcinoma

Purpose: Endoglin (CD105) is an endothelial cell membrane receptor highly expressed on proliferating tumor vasculature, including that of hepatocellular carcinoma (HCC), and is associated with poor prognosis. Endoglin is essential for angiogenesis, and its expression is induced by hypoxia and VEGF pathway inhibition. TRC105 is a chimeric IgG1 CD105 mAb that inhibits angiogenesis and causes antibody-dependent cellular cytotoxicity and apoptosis of proliferating endothelium.Experimental Design: Patients with HCC (Child-Pugh A/B7), ECOG 0/1, were enrolled in a phase I study of TRC105 at 3, 6, 10, and 15 mg/kg every 2 weeks given with sorafenib 400 mg twice daily. Correlative biomarkers included DCE-MRI and plasma levels of angiogenic factors, including soluble endoglin. Pharmacokinetics were assessed in serum.Results: Twenty-six patients were enrolled, of whom 25 received treatment, 15 with cirrhosis. Hep B/C: 3/15; M:F 19:6; mean age of 60 (range, 18-76); 1 DLT (grade 3 AST) occurred at 10 mg/kg. The most frequent toxicity was low-grade epistaxis, a known toxicity of TRC105. One patient experienced an infusion reaction and was replaced. One patient with coronary stenosis developed a fatal myocardial infarction, and one patient developed G3 cerebral tumor hemorrhage. MTD was not established and DL4 (15 mg/kg) was expanded. The overall response rate in 24 evaluable patients at all 4 dose levels was 21% [95% confidence interval (CI), 7.1-42.2], and 25% (95% CI, 8.7-49.1) in patients with measureable disease. Four patients had confirmed stable disease, one of whom was treated for 22 months. Median progression-free survival (PFS) for 24 patients evaluable for PFS was 3.8 months (95% CI, 3.2-5.6 months); median overall survival was 15.5 months (95% CI, 8.5-26.3 months).Conclusions: TRC105 combined with sorafenib was well tolerated at the recommended single agent doses of both drugs. Encouraging evidence of activity to date (PR rate 25%) was observed, and the study is now continuing to recruit in the phase II stage as a multicenter study to confirm activity of the combination. Clin Cancer Res; 23(16); 4633-41. ©2017 AACR.

Immunohistochemical Expression of CD105 and TGF-β1 in Oral Squamous Cell Carcinoma and Adjacent Apparently Normal Oral Mucosa and its Correlation With Clinicopathologic Features

Angiogenesis in oral squamous cell carcinomas (OSCC) is essential for its growth, invasion, and metastasis. This entails a shift in the balance between proangiogenic and antiangiogenic factors. CD105 and TGF-β1 are 2 such proangiogenic factors wherein CD105 exerts its angiogenic effect by binding to and modulating the TGF-β1 pathway. A total of 50 resected specimens of OSCC were considered. One tissue specimen was taken from tumor proper and another specimen from adjacent apparently normal mucosa (AANM). Both tissues were immunohistochemically stained using CD105 and TGF-β1 antibodies. The expression of each antibody was individually assessed and then compared. Pearson χ test was used for statistical comparison of expression. CD105 was significantly expressed in OSCC as compared with AANM and also correlated with increasing TNM stage. The mean microvessel density was higher in OSCC. TGF-β1 was significantly expressed in epithelium of OSCC as compared with AANM. On comparing expression of TGF-β1 and CD105, 79.54% of endothelial cells expressed positivity for both molecules. Both CD105 and TGF-β1 were increased in OSCC, although based on our results CD105 alone can be used as a prognostic marker. On the basis of immunohistochemical expression of CD105 and TGF-β1 in endothelial cells, our results demonstrate that CD105 acts as one of the receptors of TGF-β1 on endothelial cells and induces the angiogenic pathway in OSCC.

Subtractive Cell-SELEX Selection of DNA Aptamers Binding Specifically and Selectively to Hepatocellular Carcinoma Cells with High Metastatic Potential

Relapse and metastasis are two key risk factors of hepatocellular carcinoma (HCC) prognosis; thus, it is emergent to develop an early and accurate detection method for prognostic evaluation of HCC after surgery. In this study, we sought to acquire oligonucleotide DNA aptamers that specifically bind to HCC cells with high metastatic potential. Two HCC cell lines derived from the same genetic background but with different metastatic potential were employed: MHCC97L (low metastatic properties) as subtractive targets and HCCLM9 (high metastatic properties) as screening targets. To mimic a fluid combining environment, initial DNA aptamers library was firstly labelled with magnetic nanoparticles using biotin-streptavidin system and then applied for aptamers selection. Through 10-round selection with subtractive Cell-SELEX, six aptamers, LY-1, LY-13, LY-46, LY-32, LY-27/45, and LY-7/43, display high affinity to HCCLM9 cells and do not bind to MHCC97L cells, as well as other tumor cell lines, including breast cancer, lung cancer, colon adenocarcinoma, gastric cancer, and cervical cancer, suggesting high specificity for HCCLM9 cells. Thus, the aptamers generated here will provide solid basis for identifying new diagnostic targets to detect HCC metastasis and also may provide valuable clues for developing new targeted therapeutics.

A phase II study of TRC105 in patients with hepatocellular carcinoma who have progressed on sorafenib

BACKGROUND

Endoglin is an endothelial cell membrane receptor essential for angiogenesis and highly expressed on the vasculature of many tumor types, including hepatocellular carcinoma (HCC). TRC105 is a chimeric IgG1 anti-CD105 monoclonal antibody that inhibits angiogenesis and tumor growth by endothelial cell growth inhibition, ADCC and apoptosis, and complements VEGF inhibitors.

OBJECTIVE

The aim of this phase II study was to evaluate the efficacy of anti-endoglin therapy with TRC105 in patients with advanced HCC, post-sorafenib.

METHODS

Patients with HCC and compensated liver function (Childs-Pugh A/B7), ECOG 0/1, were enrolled to a single-arm, phase II study of TRC105 15 mg/kg IV every two weeks. Patients must have progressed on or been intolerant of prior sorafenib. A Simon optimal two-stage design was employed with a 50% four-month PFS target for progression to the second stage. Correlative biomarkers evaluated included DCE-MRI as well as plasma levels of angiogenic biomarkers and soluble CD105.

RESULTS

A total accrual of 27 patients was planned. However, because of lack of efficacy and in accordance with the Simon two-stage design, 11 patients were enrolled. There were no grade 3/4 treatment-related toxicities. Most frequent toxicities were headache (G2; N = 3) and epistaxis (G1; N = 4). One patient had a confirmed partial response by standard RECIST criteria and biologic response on DCE-MRI but the four-month PFS was insufficient to proceed to the second stage of the study.

CONCLUSIONS

TRC105 was well tolerated in this HCC population following sorafenib. Although there was evidence of clinical activity, this did not meet prespecified criteria to proceed to the second stage. TRC105 development in HCC continues as combination therapy with sorafenib.

Endoglin (CD 105) as a potential prognostic factor in neuroblastoma

BACKGROUND

Endoglin (CD105) is a cytokine that modulates angiogenesis by regulating different cellular functions, including endothelial proliferation, differentiation, migration and formation of microvessels. CD105 is expressed strongly in the tumor vasculature, and intratumoral microvessel density (IMVD), as determined by the use of antibodies to CD105, it has been found to be an important prognostic indicator for outcome in various malignances. This study aims to determine if the clinical outcome of children with neuroblastoma is correlated with IMVD, as determined by CD105 staining and other prognostic factors.

PROCEDURE

Tumor tissue specimens from 38 patients with peripheral neuroblastic tumors who underwent surgical resection or biopsy of their primary tumor without any preoperative therapy were retrospectively reviewed. IMVD was identified immunohistochemically using monoclonal antibodies against CD105. Prognostic factors, such as the MYCN oncogene, disease stage, histopathology and age, were correlated with outcome.

RESULTS

Among 38 examined specimens, the median IMVD value was 23.2 (15.1-28.4). The IMVD identified by CD105 was significantly higher in patients with unfavorable histology, metastatic disease, MYCN amplification and COG high risk group. ROC analysis was used to find significant IMVD level regarding EFS. The cut-off >18 was selected according to the greatest sensitivity (100%) and specificity (68.42%). The multivariate Cox proportional hazards analysis demonstrated that MYCN amplification and IMVD were significant prognostic factors in predicting EFS (hazard ratio for MYCN amplification: 3.61; 95% CI: 1.20-10.90; P = 0.023 and for IMVD: 1.05; 95% CI: 1.00-1.09; P = 0.037).

CONCLUSION

IMVD determined by CD105 appeared to be an independent prognostic factor for neuroblastoma.

[Vascularization of hepatoceliular carcinoma]

The paper gives the data available in the literature on vascularization of hepatocellular carcinoma (HCC). Sinusoidal capillarization and unpaired arteries are shown to play an important role in the development and progression of HCC. The density of microvessels detected by immunohistochemical techniques is a morphological indicator of the degree of angiogenic processes. Higher-grade HCC is followed by changes in its vascularization and concurrent with a progressive increase in the proportion of blood entering along the hepatic artery. The morphological indicators of microvessel density are recommended to use as addi- tional criteria for determining the prognosis of the disease, designing targeted anti-angiogenic drugs, and evaluating the efficiency of performed therapy.

Management of hepatocellular carcinoma: Predictive value of immunohistochemical markers for postoperative survival

Hepatocellular carcinoma (HCC) accounts for over 90% of all primary liver cancers. With an ever increasing incidence trend year by year, it has become the third most common cause of death from cancer worldwide. Hepatic resection is generally considered to be one of the most effective therapies for HCC patients, however, there is a high risk of recurrence in postoperative HCC. In clinical practice, there exists an urgent need for valid prognostic markers to identify patients with prognosis, hence the importance of studies on prognostic markers in improving the prediction of HCC prognosis. This review focuses on the most promising immunohistochemical prognostic markers in predicting the postoperative survival of HCC patients.

An open-label phase Ib dose-escalation study of TRC105 (anti-endoglin antibody) with bevacizumab in patients with advanced cancer

PURPOSE

Endoglin, an endothelial cell membrane receptor expressed on angiogenic tumor vessels, is essential for angiogenesis and upregulated in the setting of VEGF inhibition. TRC105 is an anti-endoglin IgG1 monoclonal antibody that potentiates VEGF inhibitors in preclinical models. This study assessed safety, pharmacokinetics, and antitumor activity of TRC105 in combination with bevacizumab.

EXPERIMENTAL DESIGN

Patients (n = 38) with advanced solid tumors, Eastern Cooperative Group performance status 0-1, and normal organ function were treated with escalating doses of TRC105 plus bevacizumab until disease progression or unacceptable toxicity using a standard 3 + 3 phase I design.

RESULTS

TRC105 and bevacizumab were well tolerated at their recommended single-agent doses (10 mg/kg) when the initial dose of TRC105 was delayed by one week and divided over 2 days to limit the frequency of headache. The concurrent administration of bevacizumab and TRC105 did not otherwise potentiate known toxicities of TRC105 or bevacizumab. Hypertension and proteinuria were observed, though not at rates expected for single-agent bevacizumab. Several patients who had previously progressed on bevacizumab or VEGF receptor tyrosine kinase inhibitor (VEGFR TKI) treatment experienced reductions in tumor volume, including two partial responses by RECIST, and 6 remained without progression for longer periods than during their prior VEGF inhibitor therapy.

CONCLUSIONS

TRC105 was well tolerated with bevacizumab and clinical activity was observed in a VEGF inhibitor-refractory population. Ongoing clinical trials are testing TRC105 in combination with bevacizumab in glioblastoma and with VEGFR TKIs in renal cell carcinoma, hepatocellular carcinoma, and soft tissue sarcoma.

Inhibition of endoglin-GIPC interaction inhibits pancreatic cancer cell growth

Endoglin, a 180-kDa disulfide-linked homodimeric transmembrane receptor protein mostly expressed in tumor-associated endothelial cells, is an endogenous binding partner of GAIP-interacting protein, C terminus (GIPC). Endoglin functions as a coreceptor of TβRII that binds TGFβ and is important for vascular development, and consequently has become a compelling target for antiangiogenic therapies. A few recent studies in gastrointestinal stromal tumor (GIST), breast cancer, and ovarian cancer, however, suggest that endoglin is upregulated in tumor cells and is associated with poor prognosis. These findings indicate a broader role of endoglin in tumor biology, beyond angiogenic effects. The goal of our current study is to evaluate the effects of targeting endoglin in pancreatic cancer both in vitro and in vivo. We analyzed the antiproliferative effect of both RNAi-based and peptide ligand-based inhibition of endoglin in pancreatic cancer cell lines, the latter yielding a GIPC PDZ domain-targeting lipopeptide with notable antiproliferative activity. We further demonstrated that endoglin inhibition induced a differentiation phenotype in the pancreatic cancer cells and sensitized them against conventional chemotherapeutic drug gemcitabine. Most importantly, we have demonstrated the antitumor effect of both RNAi-based and competitive inhibitor-based blocking of endoglin in pancreatic cancer xenograft models in vivo. To our knowledge, this is the first report exploring the effect of targeting endoglin in pancreatic cancer cells.

Endoglin for targeted cancer treatment

Endoglin is a homodimeric cell membrane glycoprotein receptor for transforming growth factor β and bone morphogenetic proteins. Endoglin is essential for angiogenesis, being densely expressed on proliferating endothelial cells and upregulated during hypoxia. Its expression is implicated in development of resistance to vascular endothelial growth factor (VEGF) inhibition. TRC105 is an antibody that binds endoglin and prevents endothelial cell activation. Targeting endoglin and the VEGF pathway concurrently improves treatment in vitro and appears to reverse resistance to bevacizumab in some refractory cancer patients. Randomized trials are under way to assess the clinical benefit of adding TRC105 therapy to bevacizumab therapy. Further trials are under way to assess the activity of TRC105 with small-molecule inhibitors of the VEGF pathway in renal cell carcinoma, hepatocellular carcinoma, and soft tissue sarcoma. Stratification of soft tissue sarcomas based on endoglin expression levels is proposed to identify patients most likely to benefit from TRC105 treatment. The development of a TRC105 antibody-drug conjugate is also described.

Tumor vascular homing endgolin-targeted radioimmunotherapy in hepatocellular carcinoma

Endoglin is a proliferation-associated cell membrane antigen and overexpressed in the angiogenic vasculature of solid tumors. However, the applications of endoglin (ENG)-targeted radioimmunotheray in hepatocellular carcinoma have not been reported yet. Therefore, the aim of this study was the visualization of both the development of hepatocellular carcinoma (HCC) tumor burden and therapeutic effect with ENG-targeted (131)I-anti-ENG mAb (A8), via in vivo noninvasive fluorescence imaging (NIFLI) of SMMC7721-green fluorescent protein (GFP) cells. A8 showed a dose-dependent, time-dependent suppression on the proliferation of SMMC7721-GFP cells and human umbilical vein endothelial cells (HUVECs) in vitro. Tube formation assay showed that (131)I-A8 markedly inhibits HUVECs to form extensive and enclosed tube networks. The results showed that the radiochemical purity of (131)I-A8 was 92.8 % and (131)I-A8 maintained more stable in serum than in saline and had high affinity against SMMC7721-GFP cells. The pharmacokinetics of (131)I-A8 was in accordance with the two-compartment model, with a rapid distribution phase and a slow decline phase. NIFLI exhibited a good relation between the fluorescent signal and tumor volume in vivo. Furthermore, treatment with (131)I-A8 resulted in significant tumor-growth suppression on the basis of the reducing fluorescent signal and a remarkably decreased tumor weight in treated animals. These results were further verified by RT-PCR and immunohistochemistry staining. Our findings indicate that (131)I-A8 can be used as ENG-targeted therapy for hepatocellular carcinoma, and noninvasive fluorescence imaging provides valuable information on tumor burden and effectiveness of therapy.

Characterization of adipose-derived stem cells of anatomical region from mice

Background

Stem cells constitute a group of great capacity for self-renewal, long-term viability, and multi-lineage potential. Several studies have provided evidence that adipose tissue represents an alternative source of stem cells, with the main benefit of adipose-derived stem cells being that they can be easily harvested from patients by a simple minimally invasive method and can be easily cultured. The aim of this study was to establish a culture protocol for obtaining and characterizing adipose-derived stem cells (ADSCs) from C57BL/6 J mice.

Results

The results showed that the yield, viability, and cell morphology obtained differ according to the age of isolated anatomic regions of the adipose tissue from ovarian and epididymis. The results of determination of cyclin D1 showed uniformity in the expression between different populations of ADSCs. A significant increase in the expression of caspase-3 active, was also observed in large cell populations from mice after 120 days. ADSCs were positive for mesenchymal markers CD90 and CD105, Nanog, SSEA-1, CD106, and VEGFR-1, and negative for hematopoietic markers CD34 and CD45. A large number of cells in S + G2/M phases was also observed for both sexes, demonstrating high proliferative capacity of ADSCs.

Conclusions

We observed that the adipose tissue of C57BL/6 J mice, isolated from the studied anatomic regions, is a promising source for obtaining pluripotent mesenchymal stem cells with high viability and proliferative response.

Evaluation and comparison of microvessel density using the markers CD34 and CD105 in regenerative nodules, dysplastic nodules and hepatocellular carcinoma

PURPOSE

The progression of hepatocellular carcinoma (HCC) is multifactorial and angiogenesis plays a fundamental role, mainly because HCC is a highly vascularized tumor.

METHODS

In this study, we determined microvessel density (MVD) using the immunohistochemical markers, CD34 and CD105 (Endoglin), in 44 hepatectomy specimens, encompassing 44 malignant nodules (HCC), 44 regenerative nodules (RN), and 15 dysplastic nodules (DN). The evaluation included the determination of MVD in all nodules. For statistical analysis, a descriptive analysis was carried out using measurements of position and dispersion for continuous variables; ANOVA was used to compare between groups, considering p < 0.05 as statistically significant.

RESULTS

We observed a significant difference when comparing CD34 and CD105 immunoexpression in HCC, DN, and RN. CD105 was predominantly expressed in the peripheral regions in HCC, with mean MVD scores of 6.2 ± 4.1 and 10.7 ± 4.4 at the center and periphery of the nodules, respectively, with significant differences between groups (p < 0.0001). CD34 had higher mean MVD scores than CD105 in HCC, with a more uniform positivity pattern. CD105 immunoexpression in DN exhibited a pattern similar to HCC. However, in RN, CD105 exhibited a higher MVD score in the central portion of the nodules. CD105 was expressed in a subset of newly formed microvessels in HCC and demonstrated an elevated mean MVD in cirrhotic or regenerative nodules.

CONCLUSIONS

MVD determined by CD34 and CD105 expression may be used as an additional parameter to distinguish benign from malignant liver nodules.

Microvascular density of regenerative nodule to small hepatocellular carcinoma by automated analysis using CD105 and CD34 immunoexpression

Background

Angiogenesis is a proliferative process resulting in the development of new blood vessels from existing endothelial cells and is considered crucial for tumor growth and metastasis. Tumor angiogenesis can be quantified by microvascular density (MVD), which is evaluated in highly vascularized tumor areas (hot spots) by immunohistochemical assays using CD34 and CD31 pan-endothelial antibodies. More recently, CD105 has been successfully used for some tumor types because it could discriminate neovascularization. The expression of CD34 and CD105 in hepatocellular carcinomas (HCC) and hepatic precancerous lesions has been reported—although the results for CD105 are controversial—but to the best our knowledge, CD105 has not been previously investigated in dysplastic nodules (DN). We investigated and compared MVD-CD34 and MVD-CD105 immunoexpression in tissues containing different stages of hepatocarcinogenesis, including DN.

Methods

A total of 31 regenerative nodules (RN), 26 DN and 25 small HCC from explants were used for immunohistochemical tests with CD34 and CD105 antibodies. Antibody expression was quantified by computerized image analysis measurement of MVD, areas containing highly positive endothelial cells within the nodules.

Results

The median MVD for CD34 was higher in HCC than in DN and RN (p < 0.01), and was higher in DN compared with RN (p = 0.033). In contrast, MVD with CD105 was higher in RN, and the difference was significant in RN and DN compared with HCC (p = 0.019 and p = 0.012, respectively). When MVD with CD34 and CD105 were compared within a single group, there was a significant predominance of CD105 in RN and DN (p < 0.01). In addition, MVD-C34 in HCC predominated compared with MVD-CD105, but the difference was not statistically significant (p = 0.128).

Conclusions

This study identified a close relationship between CD105 and liver cirrhosis, and that CD34 antibody is a good endothelial marker for hepatic carcinogenesis. There was no difference between the use of CD105 and CD34 antibodies in preneoplastic lesions.

Biomarkers for predicting future metastasis of human gastrointestinal tumors

The recent advances in surgery and radiation therapy have significantly improved the prognosis of patients with primary cancer, and the major challenge of cancer treatment now is metastatic disease development. The 5-year survival rate of cancer patients who have distant metastasis at diagnosis is extremely low, suggesting that prediction and early detection of metastasis would definitely improve their prognosis because suitable patient therapeutic management and treatment strategy can be provided. Cancer cells from a primary site give rise to a metastatic tumor via a number of steps which require the involvement and altered expression of many regulators. These regulators may serve as biomarkers for predicting metastasis. Over the past few years, numerous regulators have been found correlating with metastasis. In this review, we summarize the findings of a number of potential biomarkers that are involved in cadherin-catenin interaction, integrin signaling, PI3K/Akt/mTOR signaling and cancer stem cell identification in gastrointestinal cancers. We will also discuss how certain biomarkers are associated with the tumor microenvironment that favors cancer metastasis.

Understanding and targeting resistance to anti-angiogenic therapies

Therapies targeting tumor angiogenesis are used in a variety of malignancies, however not all patients benefit from treatment and impact on tumor control may be transient and modest. Mechanisms of resistance to anti-angiogenic therapies can be broadly categorized into VEGF-axis dependent alterations, non-VEGF pathways, and stromal cell interactions. Complimentary combinations of agents that inhibit alternative mechanisms of blood vessel formation may optimize inhibition of angiogenesis and improve clinical benefit for patients. The purpose of this review is to detail the preclinical evidence for mechanisms of angiogenic resistance and provide an overview of novel therapeutic approaches exploiting these pathways.

Connexin-43 can delay early recurrence and metastasis in patients with hepatitis B-related hepatocellular carcinoma and low serum alpha-fetoprotein after radical hepatectomy

Background

We studied the relationships among Cx43, CD105, and VEGF in specimens of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) with different serum AFP levels with respect to recurrence and metastasis.

Methods

Expressions of Cx43, CD105, and VEGF in 234 HCC tissue specimens were examined using tissue microarray and immunohistochemistry. Cx43 mRNA expression was examined in 38 frozen HCC specimens using RT-PCR. Correlations between these expressions and tumor recurrence, metastasis, and prognosis were analyzed using Kaplan–Meier and Cox regression analyses.

Results

Cx43 expression correlated with early tumor recurrence (P = 0.001), disease-free survival (P = 0.026), and overall survival (P = 0.000) in patients with serum AFP < 400 ng/ml, but not in those with serum AFP ≥ 400 μg/L. Cx43 expression is an independent predictor of later recurrence and longer overall survival and is inversely correlated with expression of CD105 and VEGF (P = 0.018 and 0.023, respectively), histological differentiation (P = 0.002), vessel tumor embolism (P = 0.029), and focal number (P = 0.017). Immunohistochemistry showed that Cx43 expression in patients with low AFP was lower in patients with distant metastases than in those with no metastasis or those with liver metastasis. Patients with early recurrence expressed less Cx43 mRNA than did those with no recurrence (χ² = 9.827, P = 0.002).

Conclusions

Cx43 expression can delay early HCC recurrence, metastasis, and poor prognosis after radical hepatectomy in patients with HBV-related HCC and low AFP.

Endoglin for tumor imaging and targeted cancer therapy

INTRODUCTION

Although cancer treatment has evolved substantially in the past decades, cancer-related mortality rates are still increasing. Therapies targeting tumor angiogenesis, crucial for the growth of solid tumors, mainly target vascular endothelial growth factor (VEGF) and have been clinically applied during the last decade. However, these therapies have not met high expectations, which were based on therapeutic efficacy in animal models. This can partly be explained by the upregulation of alternative angiogenic pathways. Therefore, additional therapies targeting other pro-angiogenic pathways are needed.

AREAS COVERED

The transforming growth factor (TGF)-β signaling pathway plays an important role in (tumor) angiogenesis. Therefore, components of this pathway are interesting candidates for anti-angiogenic therapy. Endoglin, a co-receptor for various TGF-β family members, is specifically overexpressed in tumor vessels and endoglin expression is associated with metastasis and patient survival. Therefore, endoglin might be a good candidate for anti-angiogenic therapy. In this review, we discuss the potential of using endoglin to target the tumor vasculature for imaging and therapeutic purposes.

EXPERT OPINION

Considering the promising results from various in vitro studies, in vivo animal models and the first clinical trial targeting endoglin, we are convinced that endoglin is a valuable tool for the diagnosis, visualization and ultimately treatment of solid cancers.

CD105/Ki67 coexpression correlates with tumor progression and poor prognosis in epithelial ovarian cancer

AIM

To analyze the expression patterns of CD105 and Ki67 in human epithelial ovarian cancer (EOC) and to evaluate the clinical significance of these two markers in the progression and prognosis in EOC.

MATERIALS AND METHODS

The CD105 and Ki67 protein expression patterns in paraffin-embedded specimens gathered from 166 patients with EOC were detected by immunohistochemistry analysis. The association of CD105 and Ki67 protein expression with the prognosis in EOC was subsequently assessed.

RESULTS

The CD105 and Ki67 proteins were positively expressed in 101/166 (60.8%) and 129/166 (77.7%) of EOC patients, respectively. The CD105 tumors are more likely to have higher tumor grade (P = 0.02). Patients with positive Ki67 staining are more likely to be at the advanced stage of the disease (P = 0.008). Marker CD105 was positively correlated with Ki67 (r = 0.66, P = 0.01). In addition, Ki67 (hazards ratio [HR], 4.8; confidence interval [CI], 1.2-16.6; P = 0.008) and CD105⁺ (HR, 4.1; CI, 1.0-15.2; P = 0.01) were both independent prognostic factors for poor overall survival in EOC patients. Furthermore, combined CD105/Ki67 expression was significantly related to unfavorable overall survival (HR, 16.6; CI, 1.2-128.9; P < 0.001).

CONCLUSIONS

Our results suggest that the CD105 and Ki67 expressions might be involved in the progression of EOC and patient prognosis. A combined detection of CD105/Ki67 coexpression may benefit us in predicting the prognosis in EOC.

Phase II study of sirolimus in treatment-naive patients with advanced hepatocellular carcinoma

BACKGROUND

Rapalogs are emerging as promising targeted anticancer drugs. Activation of the PI3K/Akt/mTOR pathway has been observed in 15-50% of hepatocellular carcinomas.

METHODS

In this phase II study, patients with advanced hepatocellular carcinoma and underlying cirrhosis received sirolimus (20 mg/week for 1 month then 30 mg/week). Tumour response was assessed every 8 weeks. The primary endpoint was the objective tumour response rate according to the Response Evaluation Criteria in Solid Tumours criteria. Secondary endpoints included the objective response according to the modified Response Evaluation Criteria in Solid Tumours criteria, safety, and pharmacokinetic parameters.

RESULTS

Twenty-five patients received sirolimus for a median of 20.6 weeks. Two patients had an objective response (8%, 95CI: 0.98-26.03), including one complete response, and 8 patients had stable disease. There were 2 cases of grade 5 toxicity (infections) and 5 cases of grade 3 toxicity. The main grade 1/2 toxicity was mild transient fatigue (76%). Median time to radiological progression and overall survival were 15.3 weeks (range: 8.2-173.9) and 26.4 weeks (range: 8.2-173.9) respectively. Use of the modified Response Evaluation Criteria in Solid Tumours criteria did not identify any further responders.

CONCLUSION

These data suggest that first-line sirolimus shows antitumoural efficacy in advanced hepatocellular carcinoma. Larger trials with Child A patients are needed.

Endoglin - a marker of vascular endothelial cell proliferation in cancer

Endoglin (CD105) is an accessory receptor of transforming growth factor B. The highest synthesis, as well as expression, of endoglin has been found in vascular endothelial cells. The involvement of endoglin in angiogenesis and in angiogenesis-dependent processes has been observed.

Endoglin promotes angiogenesis not only by activation of vascular endothelial cell proliferation but also by induction of the antiapoptotic pathway in hypoxic endothelial cells.

The potential application of endoglin as a tumour angiogenesis marker, useful for cancer diagnostics and clinical application, is anticipated. Endoglin expression may be useful as an indicator of disease progression and helpful for estimation of recurrence and metastasis risk.

AIB1 as an independent prognostic marker in hepatocellular carcinoma after hepatic resection

BACKGROUND

Amplified in breast cancer 1 (AIB1) has been shown to promote growth and invasion in several types of human cancers and to have a prognostic role in some of cancers. However, its prognostic significance in hepatocellular carcinoma (HCC) remains unknown. This study aimed to address the issue.

METHODS

Immunohistochemical staining of AIB1 was performed for HCC and paired paratumorous liver (PTL) tissues from 139 patients. Associations between AIB1 expression with clinicopathological variables and patient survival were evaluated.

RESULTS

The expression rate of AIB1 was significantly higher in HCC (71/139, 51.1%) than in PTL tissues (1/139, 0.72%, P < 0.001). AIB1 expression in HCC was significantly associated with serum α-fetoprotein levels (P = 0.001) and Edmondson-Steiner grade (P = 0.038). Higher AIB1 expression in HCC was associated with shorter cumulative overall survival of the patients. Multivariate Cox regression analysis revealed that AIB1 was of independent prognostic significance for HCC.

CONCLUSIONS

AIB1 is independently associated with poor prognosis of HCC.

Contribution of biomarkers and imaging in the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent malignant tumour of the liver. HCC prognosis is dependent on the determination of the tumour stage by conventional imaging and early screening. However, patient survival can vary with the same tumour stage. Biomarkers thus have a role in providing an earlier diagnosis, better prognosis classification before treatment and classification prognosis during treatment. In this review article, we will provide a successive, detailed description of the serum, pathological, molecular and imaging markers of HCC.

Endoglin-targeted cancer therapy

Vascular-targeting antiangiogenic therapy (VTAT) of cancer can be advantageous over conventional tumor cell targeted cancer therapy if an appropriate target is found. Our hypothesis is that endoglin (ENG; CD105) is an excellent target in VTAT. ENG is selectively expressed on vascular and lymphatic endothelium in tumors. This allows us to target both tumor-associated vasculature and lymphatic vessels to suppress tumor growth and metastasis. ENG is essential for angiogenesis/vascular development and a co-receptor of TGF-β. Our studies of selected anti-ENG monoclonal antibodies (mAbs) in several animal models and in vitro studies support our hypothesis. These mAbs and/or their immunoconjugates (immunotoxins and radioimmunoconjugates) induced regression of preformed tumors as well as inhibited formation of new tumors. In addition, they suppressed metastasis. Several mechanisms were involved in the suppressive activity of the naked (unconjugated) anti-ENG mAbs. These include direct growth suppression of proliferating endothelial cells, induction of apoptosis, ADCC (antibody-dependent cell-mediated cytotoxicity) and induction of T cell immunity. To facilitate clinical application, we generated a human/mouse chimeric anti-ENG mAb termed c-SN6j and performed studies of pharmacokinetics, toxicology and immunogenicity of c-SN6j in nonhuman primates. No significant toxicity was detected by several criteria and minimal immune response to the murine part of c-SN6j was detected after multiple i.v. injections. The results support our hypothesis that c-SN6j can be safely administered in cancer patients. This hypothesis is supported by the ongoing phase 1 clinical trial of c-SN6j (also known as TRC105) in patients with advanced or metastatic solid cancer in collaboration with Tracon Pharma and several oncologists (NCT00582985).

Developing better treatments in hepatocellular carcinoma

The marked heterogeneity of hepatocellular carcinoma (HCC), particularly with regard to the etiology and severity of the underlying cirrhosis, makes clinical trial design in this disease very challenging. In addition, despite the global burden of HCC, there have been relatively few randomized studies. The major advance in medical therapy in HCC has been the benefit of sorafenib, as demonstrated in two Phase III studies. However, the benefit is small, and new therapies to augment or replace sorafenib are urgently needed. These newer therapies, as well as the progress made in two important areas – clinical trial design and molecular characterization – are the subject of this article.

Hepatocellular carcinomas in cirrhotic and noncirrhotic human livers share angiogenic characteristics

BACKGROUND

The antiangiogenic drug sorafenib has been shown to be an effective treatment for hepatocellular carcinoma (HCC) in patients with liver cirrhosis. It might also be effective in noncirrhotic HCC provided that the angiogenic properties of both tumor types are comparable. The aim of this study is to compare endothelial cell dynamics, microvessel density (MVD), and vessel maturation as indirect markers of angiogenesis in human HCC in cirrhotic and noncirrhotic livers.

MATERIALS AND METHODS

In a tertiary care setting, 70 consecutive HCC tumors were analyzed for endothelial cell dynamics. CD34 was applied to identify tumor microvessels, double immunolabeling Ki67/CD34 and activated caspase-3/CD34 to assess endothelial cell proliferation and apoptosis, and alpha-smooth muscle actin/CD34 for pericyte coverage. These characteristics were compared in cirrhotic (n = 33) and noncirrhotic HCCs (n = 37). Microvessel density was correlated with radiological signs of hypervascularity as obtained with dynamic four-phase CT scans during the arterial and portal phase of contrast enhancement.

RESULTS

Microvessels in cirrhotic and noncirrhotic HCC were mainly mature. In both groups endothelial cell turnover was low and MVD was not different. There was no correlation between MVD and venous invasion, tumor size, and turnover of tumor cells or endothelial cells. MVD was negatively correlated with contrast washout in the portal venous phase of CT scanning. In transplanted patients, MVD was not correlated with survival, whereas in patients after liver resection a high MVD was associated with a better prognosis.

CONCLUSION

Angiogenic characteristics of HCC in cirrhotic and noncirrhotic livers have a remarkable similarity.

ALK5 phosphorylation of the endoglin cytoplasmic domain regulates Smad1/5/8 signaling and endothelial cell migration

Endoglin, an endothelial cell-specific transforming growth factor-beta (TGF-beta) superfamily coreceptor, has an essential role in angiogenesis. Endoglin-null mice have an embryonic lethal phenotype due to defects in angiogenesis and mutations in endoglin result in the vascular disease hereditary hemorrhagic telangiectasia type I. Increased endoglin expression in the proliferating endothelium of tumors has been correlated with metastasis, tumor grade and decreased survival. Although endoglin is thought to regulate TGF-beta superfamily signaling in endothelial cells through regulating the balance between two TGF-beta-responsive pathways, the activin receptor-like kinase 5 (ALK5)/Smad2/3 pathway and the activin receptor-like kinase 1 (ALK1)/Smad1/5/8 pathway, the mechanism by which endoglin regulates angiogenesis has not been defined. Here, we investigate the role of the cytoplasmic domain of endoglin and its phosphorylation by ALK5 in regulating endoglin function in endothelial cells. We demonstrate that the cytoplasmic domain of endoglin is basally phosphorylated by ALK5, primarily on serines 646 and 649, in endothelial cells. Functionally, the loss of phosphorylation at serine 646 resulted in a loss of endoglin-mediated inhibition of Smad1/5/8 signaling in response to TGF-beta and endothelial cell migration, whereas loss of phosphorylation at both serines 646 and 649 resulted in a loss of endoglin-mediated inhibition of Smad1/5/8 signaling in response to bone morphogenetic protein-9. Taken together, these results support endoglin phosphorylation by ALK5 as an important mechanism for regulating TGF-beta superfamily signaling and migration in endothelial cells.

Novel role for epidermal growth factor-like domain 7 in metastasis of human hepatocellular carcinoma

Epidermal growth factor-like domain 7 (Egfl7) is a recently identified secreted protein that is believed to be primarily expressed in endothelial cells (ECs). Although its expression was reported elevated during tumorigenesis, whether and how Egfl7 contributes to human malignancies remains unknown. In the present study overexpression of Egfl7 was found predominantly in hepatocellular carcinoma (HCC) cells in HCC tissues and closely correlated with poor prognosis of HCC. The expression of Egfl7 in cancer cells was further verified with HCC cell lines including HepG2, MHCC97-L, and HCCLM3, and the Egfl7 expression levels positively correlated with metastatic potential of HCC cell lines was tested. To functionally characterize Egfl7 in HCC, we depleted its expression in HCCLM3 cells by using small interfering RNA. Interestingly, reduction of Egfl7 expression resulted in significant inhibition of migration but not growth of HCCLM3 cells. Biochemical analysis indicated that Egfl7 could facilitate the phosphorylation of focal adhesion kinase (FAK) and therefore promote the migration of HCCLM3 cells. In addition, this effect was almost completely blocked by inhibition of epidermal growth factor receptor (EGFR), indicating that the activation of FAK by Egfl7 is mediated through EGFR. Finally, we used a mouse model to demonstrate that down-regulation of Egfl7 was associated with suppression of intrahepatic and pulmonary metastases of HCC. Collectively, our study shows for the first time that overexpression of Egfl7 in HCC and Egfl7 promotes metastasis of HCC by enhancing cell motility through EGFR-dependent FAK phosphorylation.

CONCLUSION

Our study suggests Egfl7 as a novel prognostic marker for metastasis of HCC and a potential therapeutic target.

A somatostatin analogue, octreotide, inhibits the occurrence of second primary tumors and lung metastasis after resection of hepatocellular carcinoma in mice

Occurrence of second primary tumors and metastasis remains the major obstacles to prolonged survival of patients with primary hepatocellular carcinoma (HCC). A somatostatin analogue, octreotide, has been previously reported to inhibit the growth of human HCC xenografts in nude mice through its anti-angiogenic activity. It is therefore important to investigate whether octreotide could prevent second primary hepatomas or distant metastasis following resection of primary HCC. In this study, nude mice, bearing the human HCC xenografts with highly metastatic potential (LCI-D20) in the left liver lobe, underwent tumor resection, and received intraperitoneal administration of octreotide or saline as a control for 35 consecutive days. Compared with the control group, octreotide at the doses of 100 and 200 microg/kg/day significantly inhibited the growth (P < 0.001 and P < 0.001, respectively) and incidence of second primary tumors (P = 0.016 and P = 0.001, respectively), decreased lung metastasis (P < 0.001 and P < 0.001, respectively), and prolonged the life span (P = 0.029 and P = 0.006, respectively). Moreover, intratumoral angiogenesis quantified by microvessel density as well as serum and tissue vascular endothelial growth factor (VEGF) levels were considerably decreased in octreotide-treated animals compared to the control animals. These findings suggest that octreotide may prevent the occurrence of second primary hepatomas and lung metastasis after resection of primary HCC, which may be partially attributed to down-regulation of VEGF and subsequent reduction in tumor angiogenesis. Octreotide administration may be useful as an adjuvant therapy to improve survival of patients with HCC.

Human hepatocellular carcinoma tumor-derived endothelial cells manifest increased angiogenesis capability and drug resistance compared with normal endothelial cells

PURPOSE

Increasing evidence indicates that tumor-derived endothelial cells (TEC) possess a distinct and unique phenotype compared with endothelial cells (NEC) from adjacent normal tissue and may be able to acquire resistance to drugs. The aim of this study was to investigate the angiogenesis activity and response to drug treatment of TECs and NECs derived from human hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

TECs or NECs were isolated from HCC or adjacent normal liver tissue using anti-CD105 antibody coupled to magnetic beads. The phenotypic and functional properties of endothelial cells were characterized by testing the expression of CD105, CD31, CD144, vascular endothelial growth factor receptor-1, vascular endothelial growth factor receptor-2, and von Willebrand factor, and the ability of DiI-Ac-LDL-uptake and tube formations. CD105(+) TECs were compared with CD105(+) NECs and human umbilical vein endothelial cells (HUVEC) by examining their ability to proliferate, motility, ability to adhere to tumor cells, response to tumor conditioned medium, and reactions to the chemotherapy drugs Adriamycin and 5-fluorouracil and the antiangiogenic drug sorafenib.

RESULTS

Compared with CD105(+) NECs and HUVECs, CD105(+) TECs showed increased apoptosis resistance and motility and proangiogenic properties. Meanwhile, CD105(+) TECs had a greater ability to adhere to tumor cells and survive in the tumor environment. Moreover, CD105(+) TECs acquired more resistance to Adriamycin, 5-fluorouracil, and sorafenib than CD105(+) NECs and HUVECs.

CONCLUSIONS

TECs possessed enhanced angiogenic activity and resistance to chemotherapeutic drugs and an angiogenesis inhibitor, and may provide a better tool for studying tumor angiogenesis and antiangiogenesis drugs in HCC.

Decreased expression of inhibitor of growth 4 correlated with poor prognosis of hepatocellular carcinoma

OBJECTIVE

Inhibitor of growth 4 (ING4) is a candidate tumor suppressor that plays an important role in tumor growth and angiogenesis. Here, we examined the expression of ING4 in hepatocellular carcinoma (HCC) tissues and analyzed its correlation with the progression of HCC.

METHODS

Specimens from 136 HCC patients were determined immunohistochemically for ING4 expression. The correlation of ING4 levels with clinicopathologic variables, prognosis, and metastatic potential was analyzed. Among the 136 cases, 36 paired HCC and paracarcinomatous liver tissue specimens were analyzed for ING4 expression levels by real-time quantitative reverse transcription-PCR and Western blotting. MVD was determined by CD34 immunostaining to test whether it correlated with ING4 protein expression level.

RESULTS

The ING4 mRNA and protein levels were significantly lower in HCC than paracarcinomatous liver tissue from both real-time quantitative reverse transcription-PCR and Western blotting (P = 0.039 and 0.012, respectively). Importantly, the ING4 protein level correlated with the Edmondson-Steiner grade (P = 0.035), vein invasion (P = 0.015), and microvessel density (P = 0.005). Survival and metastasis analysis indicated that HCC patients with lower ING4 expression had poorer overall survival and disease-free survival than those with high expression (P = 0.0001 and 0.0065; respectively). Multivariable Cox regression analysis revealed that the ING4 expression level was an independent factor for prognosis (hazard risk, 9.63; P = 0.001).

CONCLUSIONS

ING4 expression is down-regulated in HCC tissues. ING4 expression level correlates with prognosis and metastatic potential, which suggests that ING4 is a candidate prognostic marker of HCC.