Metastasis: recent discoveries and novel treatment strategies

Future of circulating tumor cells in the melanoma clinical and research laboratory settings

Circulating tumor cells (CTC) have become a field of interest for oncologists based on the premise that they constitute the underpinning for metastatic dissemination. The lethal nature of cancer is no longer attributed to solid tumor formation, but rather to the process of metastasis; shifting the focus of current studies towards the isolation and identification of metastatic progenitors, such as CTCs. CTCs originate from primary tumor masses that undergo morphologic and genetic alterations, which involve the release of mesenchymal-like cancer cells into the bloodstream, capable of invading nearby tissues for secondary tumor development. Cancerous cells contained in the primary tumor mass acquire the motile mesenchymal phenotype as a result of the Epithelial-to-Mesenchymal Transition, where substantial variations in protein expression and signaling pathways take place. CTCs that migrate from the primary tumor, intravasate into the systemic vasculature, are transported through the bloodstream, and invade tissues and organs suitable for secondary tumor development. While only a limited number of CTCs are viable in the bloodstream, their ability to elude the immune system, evade apoptosis and successfully metastasize at secondary tumor sites, makes CTCs promising candidates for unraveling the triggers that initiates the metastatic process. In this article, these subjects are explored in greater depth to elucidate the potential use of CTCs in the detection, disease staging and management of metastatic melanoma.

Osteosarcoma Overview

Osteosarcoma (OS) is the most common primary malignancy of bone and patients with metastatic disease or recurrences continue to have very poor outcomes. Unfortunately, little prognostic improvement has been generated from the last 20 years of research and a new perspective is warranted. OS is extremely heterogeneous in both its origins and manifestations. Although multiple associations have been made between the development of osteosarcoma and race, gender, age, various genomic alterations, and exposure situations among others, the etiology remains unclear and controversial. Noninvasive diagnostic methods include serum markers like alkaline phosphatase and a growing variety of imaging techniques including X-ray, computed tomography, magnetic resonance imaging, and positron emission as well as combinations thereof. Still, biopsy and microscopic examination are required to confirm the diagnosis and carry additional prognostic implications such as subtype classification and histological response to neoadjuvant chemotherapy. The current standard of care combines surgical and chemotherapeutic techniques, with a multitude of experimental biologics and small molecules currently in development and some in clinical trial phases. In this review, in addition to summarizing the current understanding of OS etiology, diagnostic methods, and the current standard of care, our group describes various experimental therapeutics and provides evidence to encourage a potential paradigm shift toward the introduction of immunomodulation, which may offer a more comprehensive approach to battling cancer pleomorphism.

Astrocytes in Migration

Cell migration is a fundamental phenomenon that underlies tissue morphogenesis, wound healing, immune response, and cancer metastasis. Great progresses have been made in research methodologies, with cell migration identified as a highly orchestrated process. Brain is considered the most complex organ in the human body, containing many types of neural cells with astrocytes playing crucial roles in monitoring normal functions of the central nervous system. Astrocytes are mostly quiescent under normal physiological conditions in the adult brain but become migratory after injury. Under most known pathological conditions in the brain, spinal cord and retina, astrocytes are activated and become hypertrophic, hyperplastic, and up-regulating GFAP based on the grades of severity. These three observations are the hallmark in glia scar formation-astrogliosis. The reactivation process is initiated with structural changes involving cell process migration and ended with cell migration. Detailed mechanisms in astrocyte migration have not been studied extensively and remain largely unknown. Here, we therefore attempt to review the mechanisms in migration of astrocytes.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Casearin D inhibits ERK phosphorylation and induces downregulation of cyclin D1 in HepG2 cells

Cancer is a public health problem which represents the second cause of death in the world. In this framework, it is necessary to identify novel compounds with antineoplastic potential. Plants are an important source for discovering novel compounds with pharmacological potential. In this study, we aimed to investigate the antiproliferative potential of isolated compounds from Casearia sylvestris on tumor cell lines. Crude extract effectively reduced cell viability of 4 tumor cell lines (HepG2, A549, U251-MG, and HT-144) after 48h treatment. HepG2 and HT-144 were the most responsive cells. Three fractions (aqueous ethanol, n-hexane and ethyl acetate) were tested against HepG2 and HT-144 cells and we observed that compounds with antiproliferative activity were concentrated in n-hexane and ethyl acetate fractions. The casearins A, G and J were isolated from n-hexane fraction, while casearin D was obtained from ethyl acetate fraction. We demonstrated that casearin D significantly inhibited the clonogenic capacity of HepG2 cells after 24h exposure indicating its antiproliferative activity. In addition, G1/S transition cell cycle arrest in HepG2 cells was also observed. These effects are related, at least in part, to ability of the casearin D in reducing ERK phosphorylation and cyclin D1 expression levels.

Aspirin, lysine, mifepristone and doxycycline combined can effectively and safely prevent and treat cancer metastasis: prevent seeds from gemmating on soil

Recent scientific advances have increased our understanding of the cancer metastatic complexities and provided further impetus for new combination therapies to prevent cancer metastasis. Here, we demonstrated that a combination (HAMPT) of aspirin, lysine, mifepristone and doxycycline can effectively and safely prevent cancer metastasis. The pharmaceutically-formulated HAMPT inhibited adhesion of cancer cells to either endothelial cells or extracellular matrix via down-regulating cell adhesion molecules ICAM-1 and α₄-integrin. HAMPT inhibited the cloak effect by activated platelets on cancer cells, thereby interfering adhesion and invasion of cancer cells to the underlying stroma. At the effective concentration, HAMPT induced cancer cells into dormancy with minor inhibition on cell viability. Four-day pretreatment followed by 30-day oral administration of HAMPT (33.5-134 mg/kg) to the mice inoculated with cancer cells produced significant inhibition on cancer metastasis dose-dependently without marked side effects. Fifty-day rat toxicity study with HAMPT at doses (335-1340 mg/kg) 20-fold higher than its therapeutic dose produced no significant toxicity. Interestingly, the acute toxic death could not be reached at the maximum administrable dose (5 g/kg). This proof-of-concept study provides the first conceptual evidence that cancer metastasis can be controlled by using affordable old drugs to restrain circulating tumor cells from gemmating on the metastatic soil without the need for cytotoxicity.

Loss of COX5B inhibits proliferation and promotes senescence via mitochondrial dysfunction in breast cancer

COX5B, a peripheral subunit of the cytochrome c oxidase complex, has previously been reported to maintain the stability of this complex. However, its functions and mechanisms involved in breast cancer progression remain unclear. Here, by performing SILAC assays in breast cancer cell models and detecting COX5B expression in tissues, we found that COX5B expression was elevated in breast cancer. Down-regulation of COX5B in breast cancer cell lines can suppress cell proliferation and induced cell senescence which was accompanied by elevating production of IL-8 and other cytokines. Interestingly, conditioned medium from COX5B knockdown cells could promote breast cancer cell migration. Mechanistic studies reveal that COX5B silence induces an increase in production of ROS, depolarization of MMP and a decrease in ATP. What's more, silence of COX5B leads to metabolic disorders, such as increased glucose uptake and decreased lactate secretion. Collectively, our study shows that loss of COX5B induces mitochondrial dysfunction and subsequently leads to cell growth suppression and cell senescence. Cytokines such as IL-8 secreted by senescent cells may in turn alter the microenvironment which could enhance cell migration. These findings may provide a novel paradigm for the treatment which combined anti-cancer drugs with particular cytokine inhibitors such as IL-8 blockers.

The roles of microRNAs related with progression and metastasis in human cancers

Metastasis is an important factor in predicting the prognosis of the patients with cancers and contributes to high cancer-related mortality. Recent studies indicated that microRNAs (miRNAs) played a functional role in the initiation and progression of human malignancies. MicroRNAs are small non-coding RNAs of about 22 nucleotides in length that can induce messenger RNA (mRNA) degradation or repress mRNA translation by binding to the 3' untranslated region (3'-UTR) of their target genes. Overwhelming reports indicated that miRNAs could regulate cancer invasion and metastasis via epithelial-to-mesenchymal transition (EMT)-related and/or non-EMT-related mechanisms. In this review, we concentrate on the underlying mechanisms of miRNAs in regulating cancer progression and metastasis.

In vivo biodistribution studies and ex vivo lymph node imaging using heavy metal-free quantum dots

Quantum dots (QDs) are attractive photoluminescence probes for biomedical imaging due to their unique photophysical properties. However, the potential toxicity of QDs has remained a major obstacle to their clinical use because they commonly incorporate the toxic heavy metal cadmium within the core of the QDs. In this work, we have evaluated a novel type of heavy metal-free/cadmium-free and biocompatible QD nanoparticles (bio CFQD(®) nanoparticles) with a good photoluminescence quantum yield. Sentinel lymph node mapping is an increasingly important treatment option in the management of breast cancer. We have demonstrated their potential for lymph node mapping by ex vivo imaging of regional lymph nodes after subcutaneous injection in the paw of rats. Using photoluminescence imaging and chemical extraction measurements based on elemental analysis by inductively coupled plasma mass spectroscopy, the quantum dots are shown to accumulate quickly and selectively in the axillary and thoracic regional lymph nodes. In addition, lifetime imaging microscopy of the QD photoluminescence indicates minimal perturbation to their photoluminescence properties in biological systems.

Suppression of death receptor 5 enhances cancer cell invasion and metastasis through activation of caspase-8/TRAF2-mediated signaling

The role of death receptor 5 (DR5), a well-known cell surface pro-apoptotic protein, in the negative regulation of invasion and metastasis of human cancer cells and the underlying mechanisms are largely unknown and were hence the focus of this study. In this report, we have demonstrated that DR5 functions to suppress invasion and metastasis of human cancer cells, as evidenced by enhanced cancer cell invasion and metastasis upon genetic suppression of DR5 either by gene knockdown or knockout. When DR5 is suppressed, FADD and caspase-8 may recruit and stabilize TRAF2 to form a metastasis and invasion signaling complex, resulting in activation of ERK and JNK/AP-1 signaling that mediate the elevation and activation of matrix metalloproteinase-1 (MMP1) and eventual promotion of cancer invasion and metastasis. Our findings thus highlight a novel non-apoptotic function of DR5 as a suppressor of human cancer cell invasion and metastasis and suggest a basic working model elucidating the underlying biology.

FERMT1 mediates epithelial-mesenchymal transition to promote colon cancer metastasis via modulation of β-catenin transcriptional activity

We previously demonstrated that fermitin family member 1 (FERMT1) was significantly overexpressed in colon cancer (CC) and associated with poor metastasis-free survival. This study aimed to investigate the precise role of FERMT1 in CC metastasis and the mechanism by which FERMT1 is involved in the epithelial-mesenchymal transition (EMT). Correlations between FERMT1 and EMT markers (E-cadherin, Slug, N-cadherin and β-catenin) were examined via immunohistochemistry in a cohort of CC tissues and adjacent normal colon mucosae. A series of in vitro and in vivo assays were performed to elucidate the function of FERMT1 in CC metastasis and underlying mechanisms. The upregulated expression of FERMT1 in CC tissues correlated positively with that of Slug, N-cadherin and β-catenin, but correlated inversely with E-cadherin expression. Altered FERMT1 expression led to marked changes in the proliferation, migration, invasion and EMT markers of CC cells both in vitro and in vivo. Investigations of underlying mechanisms found that FERMT1 interacted directly with β-catenin and activated the Wnt/β-catenin signaling pathway by decreasing the phosphorylation level of β-catenin, enhancing β-catenin nuclear translocation and increasing the transcriptional activity of β-catenin/TCF/LEF. Activation of the Wnt/β-catenin pathway by CHIR99021 reversed the effect of FERMT1 knockdown, whereas inhibition of the Wnt/β-catenin pathway by XAV939 impaired the effect of FERMT1 overexpression on EMT and cell motility. In conclusion, findings of this study suggest that FERMT1 activates the β-catenin transcriptional activity to promote EMT in CC metastasis.

From cell biology to immunology: Controlling metastatic progression of cancer via microRNA regulatory networks

Recently, the study of microRNAs has expanded our knowledge of the fundamental processes of cancer biology and the underlying mechanisms behind tumor metastasis. Extensive research in the fields of microRNA and its novel mechanisms of actions against various cancers has more recently led to the trial of a first cancer-targeted microRNA drug, MRX34. Yet, these microRNAs are mostly being studied and clinically trialed solely based on the understanding of their cell biologic effects, thus, neglecting the important immunologic effects that are sometimes opposite of the cell biologic effects. Here, we summarize both the cell biologic and immunologic effects of various microRNAs and discuss the importance of considering both effects before using them in clinical settings. We stress the importance of understanding the miRNA's effect on cancer metastasis from a "systems" perspective before developing a miRNA-targeted therapeutic in treating cancer metastasis.

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FUNDAMENTAL BASIS OF METASTATIC PROCESS

Metastatic process is described as a "dissemination of neoplastic cells in a distant secondary site, in which cells proliferate to develop a mass of cells partially differentiated". The vast majority of death in solid cancers is the consequence of metastasis development which lead to vital organ dysfunction. In the present review, either recent discoveries or controversial subjects associated with metastasis process will be discussed. Indeed epithelia-mesenchymal transition (EMT), circulating tumor cells, tumor dormancy, colonization in distant organ and cancer stem cells are tackled.

MicroRNA and Metastasis

Noncoding RNAs are important regulatory molecules of cellular processes. MicroRNAs (miRNAs) are small noncoding RNAs that bind to complementary sequences in the 3' untranslated region of target mRNAs, leading to degradation of the target mRNAs and/or inhibition of their translation. Some miRNAs are essential for normal animal development; however, many other miRNAs are dispensable for development but play a critical role in pathological conditions, including tumorigenesis and metastasis. miRNA genes often reside at fragile chromosome sites and are deregulated in cancer. Some miRNAs function as oncogenes or tumor suppressors, collectively termed "oncomirs." Specific metastasis-regulating miRNAs, collectively termed "metastamirs," govern molecular processes and pathways in malignant progression in either a tumor cell-autonomous or a cell-nonautonomous manner. Recently, exosome-transferred miRNAs have emerged as mediators of the tumor-stroma cross talk. In this chapter, we focus on the functions, mechanisms of action, and therapeutic potential of miRNAs, particularly oncomirs and metastamirs.

Clinical Outcomes of Gamma Knife Radiosurgery for Metastatic Brain Tumors from Gynecologic Cancer : Prognostic Factors in Local Treatment Failure and Survival

Objective

Brain metastases in gynecologic cancer (ovarian, endometrial, and cervical cancer) patients are rare, and the efficacy of Gamma Knife Radiosurgery (GKRS) to treat these had not been evaluated. We assessed the efficacy of GKRS and prognostic factors for tumor control and survival in brain metastasis from gynecologic cancers.

Methods

This retrospective study was approved by the institutional review board. From May 1995 to October 2012, 26 women (mean age 51.3 years, range 27–70 years) with metastatic brain tumors from gynecologic cancer were treated with GKRS. We reviewed their outcomes, radiological responses, and clinical status.

Results

In total 24 patients (59 lesions) were available for follow-up imaging. The median follow-up time was 9 months. The mean treated tumor volume at the time of GKRS was 8185 mm³ (range 10–19500 mm³), and the median dose delivered to the tumor margin was 25 Gy (range, 10–30 Gy). A local tumor control rate was 89.8% (53 of 59 tumors). The median overall survival was 9.5 months after GKRS (range, 1–102 months). Age-associated multivariate analysis indicated that the Karnofsky performance status (KPS), the recursive partitioning analysis (RPA) classification, and the number of treated lesions were significant prognostic factors for overall survival (HR=0.162, p=0.008, HR=0.107, p=0.038, and HR=2.897, p=0.045, respectively).

Conclusion

GKRS is safe and effective for the management of brain metastasis from gynecologic cancers. The clinical status of the patient is important in determining the overall survival time.

Tight Junctions and the Tumor Microenvironment

PURPOSE OF REVIEW

Tight junctions (TJs) are specialized differentiations of epithelial and endothelial cell membranes. TJs play an important role in the adhesion of cells and their interaction with each other. Most cancers originate from epithelial cells. Thus, it is of significance to examine the role of TJs in the tumor microenvironment (TME) and how they affect cancer metastasis.

RECENT FINDINGS

In epithelium-derived cancers, intactness of the primary tumor mass is influenced by intercellular structures as well as cell-to-cell adhesion. Irregularities of these factors may lead to tumor dissociation and subsequent metastasis. Low expression of TJs is observed among highly metastatic cancer cells.

SUMMARY

In this review, we summarized findings from current literature in consideration of the role of TJs in relation to the TME and cancer. Deeper understanding of the mechanisms leading to TJ dysregulation is needed to facilitate the design and conceptualization of new and better therapeutic strategies for cancer.

Low-Dose Farnesyltransferase Inhibitor Suppresses HIF-1α and Snail Expression in Triple-Negative Breast Cancer MDA-MB-231 Cells In Vitro

The aggressiveness of triple-negative breast cancer (TNBC), which lacks estrogen receptor, progesterone receptor and epidermal growth factor receptor 2 (HER2), represents a major challenge in breast cancer. Migratory and self-renewal capabilities are integral components of invasion, metastasis and recurrence of TNBC. Elevated hypoxia-inducible factor-1α (HIF-1α) expression is associated with aggressiveness of cancer. Nonetheless, how HIF-1α expression is regulated and how HIF-1α induces aggressive phenotype are not completely understood in TNBC. The cytotoxic effects of farnesyltransferase (FTase) inhibitors (FTIs) have been studied in cancer and leukemia cells. In contrast, the effect of FTIs on HIF-1α expression has not yet been studied. Here, we show that clinically relevant low-dose FTI, tipifarnib (300 nM), decreased HIF-1α expression, migration and tumorsphere formation in human MDA-MB-231 TNBC cells under a normoxic condition. In contrast, the low-dose FTIs did not inhibit cell growth and activity of the Ras pathway in MDA-MB 231 cells. Tipifarnib-induced decrease in HIF-1α expression was associated with amelioration of the Warburg effect, hypermetabolic state, increases in Snail expression and ATP release, and suppressed E-cadherin expression, major contributors to invasion, metastasis and recurrence of TBNC. These data suggest that FTIs may be capable of ameliorating the aggressive phenotype of TNBC by suppressing the HIF-1α-Snail pathway. J. Cell. Physiol. 232: 192-201, 2017. © 2016 Wiley Periodicals, Inc.

Value of MR histogram analyses for prediction of microvascular invasion of hepatocellular carcinoma

The objective is to explore the value of preoperative magnetic resonance (MR) histogram analyses in predicting microvascular invasion (MVI) of hepatocellular carcinoma (HCC).Fifty-one patients with histologically confirmed HCC who underwent diffusion-weighted and contrast-enhanced MR imaging were included. Histogram analyses were performed and mean, variance, skewness, kurtosis, 1th, 10th, 50th, 90th, and 99th percentiles were derived. Quantitative histogram parameters were compared between HCCs with and without MVI. Receiver operating characteristics (ROC) analyses were generated to compare the diagnostic performance of tumor size, histogram analyses of apparent diffusion coefficient (ADC) maps, and MR enhancement.The mean, 1th, 10th, and 50th percentiles of ADC maps, and the mean, variance. 1th, 10th, 50th, 90th, and 99th percentiles of the portal venous phase (PVP) images were significantly different between the groups with and without MVI (P <0.05), with area under the ROC curves (AUCs) of 0.66 to 0.74 for ADC and 0.76 to 0.88 for PVP. The largest AUC of PVP (1th percentile) showed significantly higher accuracy compared with that of arterial phase (AP) or tumor size (P <0.001).MR histogram analyses-in particular for 1th percentile for PVP images-held promise for prediction of MVI of HCC.

LncRNA TUG1 is upregulated and promotes cell proliferation in osteosarcoma

OBJECTIVE

To examine the expression and function of long non-coding RNA taurine up-regulated 1 (TUG1) in human osteosarcoma cells.

METHODS

Real-time quantitive PCR was used to detect the transcription level of TUG1 in a series of osteosarcoma cell lines. Knockdown of TUG1 in U2OS cells was carried out by transient transfection of siRNAs. MTT assay was performed to access the cell growth rates. Afterwards, RNA and protein of these cells were extracted to analyze the transfection efficient as well as the expression of other molecules.

RESULTS

Compared to the normal cell line, TUG1 exhibited a significant upregulation in osteosarcoma cells. Phenotyping analysis showed the growth-promotion activity of TUG1, since knockdown of TUG1 resulted in declined proliferation. We also found that AKT phosphorylation was impaired after TUG1 was inhibited, suggesting that the AKT pathway was involved in the regulation of TUG1 in U2OS cells.

CONCLUSION

Our data provided evidence that TUG1 was upregulated and acted as a possible oncogene via positively regulating cell proliferation in osteosarcoma cells.

Transfer of malignant trait to BRCA1 deficient human fibroblasts following exposure to serum of cancer patients

Background

It was reported that metastases might occur via transfer of biologically active blood circulating molecules from the primary tumor to distant organs rather than only migration of cancer cells. We showed in an earlier study that exposure of immortalized human embryonic kidney cells (HEK 293) to cancer patient sera, induce their transformation into undifferentiated cancers due to a horizontal transfer of malignant traits. In the present work, we tested the hypothesis that even other human cells as long as they are deficient for a single oncosuppressor gene might undergo malignant transformation when exposed to human cancer serum.

Methods

We used the CRISPR/Cas9 system to establish a stable BRCA1 knockout (KO) in human fibroblasts. The BRCA1-KO fibroblasts were exposed to cancer patients’ sera or healthy patients’ sera for 2 weeks. Treated cells were analyzed for cell proliferation and transformation to study their susceptibility to the oncogenic potential of cancer patients’ sera and to determine the possible mechanisms underlying their hypothesized transformation.

Results

BRCA1-KO fibroblasts treated with cancer patients’ sera displayed higher proliferation and underwent malignant transformation as opposed to wild type control fibroblasts, which were not affected by exposure to cancer patients’ sera. The malignant transformation was not seen when BRCA1-KO fibroblasts were treated with healthy human sera. Histological analysis of tumors generated by BRCA1-KO fibroblasts showed that they were carcinomas with phenotypical characteristics related to the cancers of the blood donor patients. Interestingly, BRCA1-KO fibroblasts were significantly more prone to internalize serum-derived exosomes, when compared to wild type fibroblasts. This suggests that oncosuppressor genes might protect the integrity of the cell genome also by blocking integration of cancer-derived exosomes.

Conclusion

These data support the hypothesis that any human cells carrying a single oncosuppressor mutation is capable of integrating cancer factors carried in the blood and undergo complete malignant transformation. Oncosuppressor genes might protect the cell genome by impeding the integration inside the cells of these mutating factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0360-9) contains supplementary material, which is available to authorized users.

Pragmatic medicine in solid cancer: a translational alternative to precision medicine

The precision medicine (PM) initiative is a response to the dismal outlook in solid cancer. Despite heterogeneity, common mechanistic denominators may exist across the spectrum of solid cancer. A shift from conventional research and development (R&D) toward PM will require conceptual and structural change. As individuals and as a society, we welcome innovation, but question change. We ask: In solid cancer, does PM identify and address the causes of prior failures, and, if so, are the proposed solutions feasible? And, when may we expect safer, more effective and affordable drugs in the clinic? Considerations that prompt a pragmatic rethink include a failure analysis of translational R&D in solid cancer suggesting that trials and regulations need to be aligned with the natural history of the disease. In successful therapeutic interventions in chronic, complex disease, surrogate markers and endpoints should be consistent with the Prentice's criteria. In solid cancer, drug induced tumor shrinkage, is a drug effect and not a disease response; tumor shrinkage does not reflect nor predict interruption of the disease. Overall, we support a pragmatic, multidisciplinary, and collaborative R&D, and suggest that direction be set by clinical need and utility, and by questions, not answers. PM will prove worthwhile if it could improve clinical outcomes. The lag in therapeutics relative to diagnostics is a cause for confusion. Overdiagnosis adds to fear and harm, especially in the absence of effective interventions. A revised initiative that prioritizes metastasis research could replicate the successful HIV/AIDS model in solid cancer. A pragmatic approach may further translational efforts toward meaningfully effective, generally available, and affordable solutions.

Filamin A phosphorylation by Akt promotes cell migration in response to arsenic

We had previously reported that trivalent arsenic (As³⁺), a well-known environmental carcinogen, induces phosphorylation of several putative Akt substrates. In the present report, we characterized one of these substrates by immunoprecipitation and proteomics analysis. The results indicate that a cytoskeleton remodeling protein, filamin A, with a molecular weight around 280 kDa, is phosphorylated by Akt in HEK-293 cells treated with As³⁺, which was also confirmed in human bronchial epithelial cell line, BEAS-2B cells. Additional biochemical and biological studies revealed that serine 2152 (S2152) of filamin A is phosphorylated by activated Akt in the cells treated with As³⁺. To further confirm the importance of Akt-dependent filamin A S2152 phosphorylation in As³⁺-induced cell migration, we over-expressed either wild type filamin A or the mutated filamin A in which the S2152 was substituted with alanine (S2152A). The capability of cell migration was reduced significantly in the cells expressing the mutated filamin A (S2152A). Clinically, we found that increased expression of filamin A predicts poorer overall survival of the lung cancer patients with adenocarcinoma. Thus, these data suggest that Akt dependent filamin A phosphorylation is one of the key events in mediating As³⁺-induced carcinogenesis. Antagonizing Akt signaling can ameliorate As³⁺-induced filamin A phosphorylation and cell migration, which may serve as a molecular targeting strategy for malignancies associated with environmental As³⁺ exposure.

Renal and retroperitoneal metastasis from prostate adenocarcinoma: a case report

BACKGROUND

Diffuse renal and retroperitoneal metastasis of prostatic origin is an uncommon spread pattern of prostate cancer.

CASE PRESENTATION

We described a 74-year-old male patient who was admitted because of dysuria and nocturia. Physical examination and imaging study indicated prostate mass, and laboratory analysis revealed elevated prostate specific antigen (PSA). The diagnosis of prostate cancer was established after biopsy. In the further evaluation, diffuse renal and retroperitoneal metastasis of prostate cancer was confirmed. Radiotherapy combined with endocrine therapy was given.

CONCLUSIONS

Our present case emphasized that the routine metastatic work-up was quite necessary, since a small proportion of men with advanced prostate cancer might experience metastases in atypical sites.

Reduced expression and prognostic implication of inhibitor of growth 4 in human osteosarcoma

Osteosarcoma is the most prevalent type of primary malignant bone tumor. Inhibitor of growth 4 (ING4) has been demonstrated to function as a tumor suppressor through multiple pathways, and is its expression is understood to be suppressed or reduced in various malignancies. The present study aimed to investigate the expression of ING4 and to determine its prognostic value in osteosarcoma tissue. Formalin-fixed, paraffin-embedded tissue microarrays were analyzed, and contained 41 osteosarcoma specimens and 11 normal bone tissue specimens with duplicate cores. ING4 expression was evaluated by immunohistochemical staining. The association between ING4 expression in the osteosarcoma and normal bone tissues was analyzed, in addition to the association between ING4 expression and Enneking classification of the osteosarcoma tissues. A significant statistical difference was observed in the ING4 immunohistochemical staining score between the osteosarcoma and normal bone tissues (P<0.001). Furthermore, a significant negative correlation was detected between the ING4 immunohistochemical staining scores and the Enneking classification results of the 41 osteosarcoma tissues (P=0.002). Low expression of ING4 was observed in the osteosarcoma specimens, and this reduced expression of ING4 was negatively correlated with Enneking classification. Thus, the results of the present study indicate that ING4 may serve as a promising prognostic marker in osteosarcoma.

Targeting ROR1 inhibits the self-renewal and invasive ability of glioblastoma stem cells

Glioblastoma is the most malignant of brain tumours and is difficult to cure because of interruption of drug delivery by the blood-brain barrier system, its high metastatic capacity and the existence of cancer stem cells (CSCs). Although CSCs are present as a small population in malignant tumours, CSCs have been studied as they are responsible for causing recurrence, metastasis and resistance to chemotherapy and radiotherapy for cancer. CSCs have self-renewal characteristics like normal stem cells. The aim of this study was to investigate whether receptor tyrosine kinase-like orphan receptor 1 (ROR1) is involved in stem cell maintenance and malignant properties in human glioblastoma. Knockdown of ROR1 caused reduction of stemness and sphere formation capacity. Moreover, down-regulation of ROR1 suppressed the expression of epithelial-mesenchymal transition-related genes and the tumour migratory and invasive abilities. The results of this study indicate that targeting ROR1 can induce differentiation of CSCs and inhibit metastasis in glioblastoma. In addition, ROR1 may be used as a potential marker for glioblastoma stem cells as well as a potential target for glioblastoma stem cell therapy.

TRAIL-R2 promotes skeletal metastasis in a breast cancer xenograft mouse model

Despite improvements in detection, surgical approaches and systemic therapies, breast cancer remains typically incurable once distant metastases occur. High expression of TRAIL-R2 was found to be associated with poor prognostic parameters in breast cancer patients, suggesting an oncogenic function of this receptor. In the present study, we aimed to determine the impact of TRAIL-R2 on breast cancer metastasis. Using an osteotropic variant of MDA-MB-231 breast cancer cells, we examine the effects of TRAIL-R2 knockdown in vitro and in vivo. Strikingly, in addition to the reduced levels of the proliferation-promoting factor HMGA2 and corresponding inhibition of cell proliferation, knockdown of TRAIL-R2 increased the levels of E-Cadherin and decreased migration. In vivo, these cells were strongly impaired in their ability to form bone metastases after intracardiac injection. Evaluating possible underlying mechanisms revealed a strong downregulation of CXCR4, the receptor for the chemokine SDF-1 important for homing of cancers cells to the bone. In accordance, cell migration towards SDF-1 was significantly impaired by TRAIL-R2 knockdown. Conversely, overexpression of TRAIL-R2 upregulated CXCR4 levels and enhanced SDF-1-directed migration. We therefore postulate that inhibition of TRAIL-R2 expression could represent a promising therapeutic strategy leading to an effective impairment of breast cancer cell capability to form skeletal metastases.

Quantitative Motion Analysis in Two and Three Dimensions

This chapter describes 2D quantitative methods for motion analysis as well as 3D motion analysis and reconstruction methods. Emphasis is placed on the analysis of dynamic cell shape changes that occur through extension and retraction of force generating structures such as pseudopodia and lamellipodia. Quantitative analysis of these structures is an underutilized tool in the field of cell migration. Our intent, therefore, is to present methods that we developed in an effort to elucidate mechanisms of basic cell motility, directed cell motion during chemotaxis, and metastasis. We hope to demonstrate how application of these methods can more clearly define alterations in motility that arise due to specific mutations or disease and hence, suggest mechanisms or pathways involved in normal cell crawling and treatment strategies in the case of disease. In addition, we present a 4D tumorigenesis model for high-resolution analysis of cancer cells from cell lines and human cancer tissue in a 3D matrix. Use of this model led to the discovery of the coalescence of cancer cell aggregates and unique cell behaviors not seen in normal cells or normal tissue. Graphic illustrations to visually display and quantify cell shape are presented along with algorithms and formulae for calculating select 2D and 3D motion analysis parameters.

Quantitative Analysis of Human Cancer Cell Extravasation Using Intravital Imaging

Metastasis, or the spread of cancer cells from a primary tumor to distant sites, is the leading cause of cancer-associated death. Metastasis is a complex multi-step process comprised of invasion, intravasation, survival in circulation, extravasation, and formation of metastatic colonies. Currently, in vitro assays are limited in their ability to investigate these intricate processes and do not faithfully reflect metastasis as it occurs in vivo. Traditional in vivo models of metastasis are limited by their ability to visualize the seemingly sporadic behavior of where and when cancer cells spread (Reymond et al., Nat Rev Cancer 13:858-870, 2013). The avian embryo model of metastasis is a powerful platform to study many of the critical steps in the metastatic cascade including the migration, extravasation, and invasion of human cancer cells in vivo (Sung et al., Nat Commun 6:7164, 2015; Leong et al., Cell Rep 8, 1558-1570, 2014; Kain et al., Dev Dyn 243:216-28, 2014; Leong et al., Nat Protoc 5:1406-17, 2010; Zijlstra et al., Cancer Cell 13:221-234, 2008; Palmer et al., J Vis Exp 51:2815, 2011). The chicken chorioallantoic membrane (CAM) is a readily accessible and well-vascularized tissue that surrounds the developing embryo. When the chicken embryo is grown in a shell-less, ex ovo environment, the nearly transparent CAM provides an ideal environment for high-resolution fluorescent microcopy approaches. In this model, the embryonic chicken vasculature and labeled cancer cells can be visualized simultaneously to investigate specific steps in the metastatic cascade including extravasation. When combined with the proper image analysis tools, the ex ovo chicken embryo model offers a cost-effective and high-throughput platform for the quantitative analysis of tumor cell metastasis in a physiologically relevant in vivo setting. Here we discuss detailed procedures to quantify cancer cell extravasation in the shell-less chicken embryo model with advanced fluorescence microscopy techniques.

Breast Cancer Metastasis Suppressor 1 (BRMS1): Robust Biological and Pathological Data, But Still Enigmatic Mechanism of Action

Metastasis requires coordinated expression of multiple genetic cassettes, often via epigenetic regulation of gene transcription. BRMS1 blocks metastasis, but not orthotopic tumor growth in multiple tumor types, presumably via SIN3 chromatin remodeling complexes. Although there is an abundance of strong data supporting BRMS1 as a metastasis suppressor, the mechanistic data directly connecting molecular pathways with inhibition of particular steps in metastasis are not well defined. In this review, the data for BRMS1-mediated metastasis suppression in multiple tumor types are discussed along with the steps in metastasis that are inhibited.

Oncogenic MicroRNAs: Key Players in Malignant Transformation

MicroRNAs (miRNAs) represent a class of non-coding RNAs that exert pivotal roles in the regulation of gene expression at the post-transcriptional level. MiRNAs are involved in many biological processes and slight modulations in their expression have been correlated with the occurrence of different diseases. In particular, alterations in the expression of miRNAs with oncogenic or tumor suppressor functions have been associated with carcinogenesis, malignant transformation, metastasis and response to anticancer treatments. This review will mainly focus on oncogenic miRNAs whose aberrant expression leads to malignancy.

Cancer Metastases: Early Dissemination and Late Recurrences

BACKGROUND

Metastatic cells from a primary tumor can occur before the primary cancer is detected. Metastatic cells can also remain in the patient for many years after removal of the primary tumor without proliferating. These dormant malignant cells can awaken and cause recurrent disease decades after the primary treatment. The purpose of this article is to review the clinical evidence for early dissemination and late recurrences in human malignant tumors. We used the following definitions: dormancy of cells may be defined as a nonproliferating state or an arrest in the cell cycle that results in a prolonged G0 phase. If one accepts the term "late metastases" to indicate a period exceeding 10 years from the removal of the primary tumor, then the two malignancies in which this occurs most frequently are cutaneous malignant melanoma (CMM) and renal cell carcinoma (RCC).

METHODS

PubMed, Web of Science, and Scopus were searched with the keywords "metastases," "early dissemination," "late recurrences," "inadvertently transmitted cancer," "tumor growth rate," "dormancy," "circulating tumor cells," and "transplantation of cancer."

RESULTS

Several case reports of early dissemination and late recurrences of various types of malignancies were found. Analyses of the growth rates of several malignant tumors in the original host indicated that the majority of cancers had metastasized years before they were detected. CMM, RCC, and malignant glioblastoma were the three most common malignancies resulting from an organ transplantation. CMM and RCC were also the two most common malignancies that showed dormancy. In several cases of transplanted CMM and RCC, the donor did not have any known malignancy or had had the malignancy removed so long ago that the donor was regarded as cured.

CONCLUSION

(1) Metastases can frequently exist prior to the detection of the primary tumor. (2) Metastatic cells may reside in organs in the original host that are not usually the site of detectable secondary tumors, for example, the kidneys and heart. (3) Metastatic cells remain dormant for decades after the primary tumor has been removed. (4) Dormancy might be reversible and lead to late recurrences.

Alkaloids derived from flowers of Senna spectabilis, (-)-cassine and (-)-spectaline, have antiproliferative activity on HepG2 cells for inducing cell cycle arrest in G1/S transition through ERK inactivation and downregulation of cyclin D1 expression

Cancer is one of the most critical problems of public health in the world and one of the main challenges for medicine in this century. Unfortunately, most patients are diagnosed at advanced stage, when the treatment options are palliative. Consequently, the search for novel therapeutic options is imperative. In the context, the plants represent an important source for discovering of novel compounds with pharmacological potential including antineoplastic agents. Herein, we aimed to investigate in vitro antiproliferative and cytotoxic potentials of an alkaloid mixture derived from Senna spectabilis, (−)-cassine (1) and (−)-spectaline (2). These alkaloids reduced cell viability in a concentration-dependent manner of six tumor cell lines. From initial screening, HepG2 cells were selected for further investigations. We show that alkaloids 1/2 have an important antiproliferative activity on HepG2 cells due to their ability in inducing cell cycle arrest in G1/S transition. This effect was associated to ERK inactivation and down-regulation of cyclin D1 expression. In addition, we evidenced a disruption of the microfilaments and microtubules in a consequence of the treatment. Taken together, the data showed by the first time that alkaloids 1/2 strongly inhibit cell proliferation of hepatocellular carcinoma cells. Therefore, they represent promise antitumor compounds against liver cancer and should be considered for further anticancer in vivo studies.

Anti-tumor enhancement of Fei-Liu-Ping ointment in combination with celecoxib via cyclooxygenase-2-mediated lung metastatic inflammatory microenvironment in Lewis lung carcinoma xenograft mouse model

Background

Fei-Liu-Ping (FLP) ointment is an oral prescription medication that has been widely applied to treat lung cancer patients in China. Regulation of the metastatic microenvironment is an important therapeutic approach for prevention and treatment of tumor recurrence and metastasis. The advantage of Traditional Chinese Medicine management of lung cancer lies in the prevention of recurrence and metastasis. Our previous study has demonstrated that FLP ointment could regulate lung inflammatory microenvironment in vitro. However, the effects of FLP on the tumor microenvironment in vivo are still poorly understood. The objective of this study is to investigate the effect of FLP alone or in combination with celecoxib in the prevention of lung cancer progression by Cyclooxygenase (Cox)-2 mediated tumor inflammatory microenvironment in vivo.

Methods

120 Lewis lung carcinoma xenograft mice were divided equally into four groups: vehicle, FLP, celecoxib, and FLP plus celecoxib. The dynamic growth of the xenografted tumors was observed using an in vivo fluorescence imaging system. Mice were sacrificed on day 14, day 21, and day 28, and tumor specimens and lung tissues were harvested to detect the metastasis-associated protein expression.

Results

Tumor inhibition rate was 15.4, 44.2, 47.4 % at day 14, 37.3, 34.7, 61.5 % at day 21, and 15.5, 10.3, 32.5 % at day 28 after treatment of FLP, celecoxib, and FLP plus celecoxib, respectively. Upon treatment of FLP and celecoxib together, lung metastasis rate was 30 % (8 metastatic nodules) lower than other groups. FLP inhibited Cox-2 expression in a time-dependent manner. Moreover, FLP inhibited N-cadherin, matrix metalloproteinases (MMP)-9, and Vimentin expression. Treatment of FLP in combination with celecoxib was more effective than FLP or celecoxib alone in inhibiting vascular endothelial growth factor, platelet-derived growth factor receptors β, microsomal Prostaglandin E synthase-1, MMP-2, MMP-9, N-cadherin, and Vimentin expression, but increased E-cadherin expression.

Conclusions

FLP inhibited tumor growth and metastasis in a Lewis lung xenograft mice model through the Cox-2 pathway. FLP in combination with celecoxib enhanced the antitumor growth and anti-metastasis effects. Traditional Chinese herbs combined with anti-inflammatory drugs might offer a promising strategy to prevent tumor metastasis.

A Versatile Microarray Platform for Capturing Rare Cells

Analyses of rare events occurring at extremely low frequencies in body fluids are still challenging. We established a versatile microarray-based platform able to capture single target cells from large background populations. As use case we chose the challenging application of detecting circulating tumor cells (CTCs) – about one cell in a billion normal blood cells. After incubation with an antibody cocktail, targeted cells are extracted on a microarray in a microfluidic chip. The accessibility of our platform allows for subsequent recovery of targets for further analysis. The microarray facilitates exclusion of false positive capture events by co-localization allowing for detection without fluorescent labelling. Analyzing blood samples from cancer patients with our platform reached and partly outreached gold standard performance, demonstrating feasibility for clinical application. Clinical researchers free choice of antibody cocktail without need for altered chip manufacturing or incubation protocol, allows virtual arbitrary targeting of capture species and therefore wide spread applications in biomedical sciences.

Moscatilin inhibits epithelial-to-mesenchymal transition and sensitizes anoikis in human lung cancer H460 cells

Metastasis in lung cancer has been recognized as an important cause of high mortality. Resistance to anoikis and the epithelial-to-mesenchymal transition (EMT) are critical factors for the successful spread of cancer cells. Compounds that suppress these features of cancer cells should be potentially active for anti-metastasis approaches. We have demonstrated for the first time that moscatilin, at its non-toxic concentrations to lung cancer cells and human normal keratinocytes, significantly decreases lung cancer cell survival in the detached condition, and suppresses the formation of tumors in an anchorage-independent growth assay. Furthermore, we found that moscatilin significantly decreased the activated level of survival proteins, namely ERK and Akt. In addition, moscatilin down-regulated cavelolin-1 (Cav-1), leading to a reduction in anti-apoptotic Mcl-1 protein. In terms of EMT, treatment of the cells with moscatilin significantly suppressed mesenchymal cell markers, namely vimentin, Slug, and Snail. These results indicate that moscatilin inhibited anoikis resistance in lung cancer cells via survival suppression, Cav-1 down-regulation, and inhibition of EMT. The compound could therefore be beneficial for the treatment and prevention of lung cancer metastasis.

Identification of Novel Ezrin Inhibitors Targeting Metastatic Osteosarcoma by Screening Open Access Malaria Box

Ezrin is a member of the ERM (ezrin, radixin, moesin) family of proteins and functions as a linker between the plasma membrane and the actin cytoskeleton. Ezrin is a key driver of tumor progression and metastatic spread of osteosarcoma. We discovered a quinoline-based small molecule, NSC305787, that directly binds to ezrin and inhibits its functions in promoting invasive phenotype. NSC305787 possesses a very close structural similarity to commonly used quinoline-containing antimalarial drugs. On the basis of this similarity and of recent findings that ezrin has a likely role in the pathogenesis of malaria infection, we screened antimalarial compounds in an attempt to identify novel ezrin inhibitors with better efficacy and drug properties. Screening of Medicines for Malaria Venture (MMV) Malaria Box compounds for their ability to bind to recombinant ezrin protein yielded 12 primary hits with high selective binding activity. The specificity of the hits on ezrin function was confirmed by inhibition of the ezrin-mediated cell motility of osteosarcoma cells. Compounds were further tested for phenocopying the morphologic defects associated with ezrin suppression in zebrafish embryos as well as for inhibiting the lung metastasis of high ezrin-expressing osteosarcoma cells. The compound MMV667492 exhibited potent anti-ezrin activity in all biologic assays and had better physicochemical properties for drug-likeness than NSC305787. The drug-like compounds MMV020549 and MMV666069 also showed promising activities in functional assays. Thus, our study suggests further evaluation of antimalarial compounds as a novel class of antimetastatic agents for the treatment of metastatic osteosarcoma.

Cancer metastases: challenges and opportunities

Cancer metastasis is the major cause of cancer morbidity and mortality, and accounts for about 90% of cancer deaths. Although cancer survival rate has been significantly improved over the years, the improvement is primarily due to early diagnosis and cancer growth inhibition. Limited progress has been made in the treatment of cancer metastasis due to various factors. Current treatments for cancer metastasis are mainly chemotherapy and radiotherapy, though the new generation anti-cancer drugs (predominantly neutralizing antibodies for growth factors and small molecule kinase inhibitors) do have the effects on cancer metastasis in addition to their effects on cancer growth. Cancer metastasis begins with detachment of metastatic cells from the primary tumor, travel of the cells to different sites through blood/lymphatic vessels, settlement and growth of the cells at a distal site. During the process, metastatic cells go through detachment, migration, invasion and adhesion. These four essential, metastatic steps are inter-related and affected by multi-biochemical events and parameters. Additionally, it is known that tumor microenvironment (such as extracellular matrix structure, growth factors, chemokines, matrix metalloproteinases) plays a significant role in cancer metastasis. The biochemical events and parameters involved in the metastatic process and tumor microenvironment have been targeted or can be potential targets for metastasis prevention and inhibition. This review provides an overview of these metastasis essential steps, related biochemical factors, and targets for intervention.

The role of endocytic Rab GTPases in regulation of growth factor signaling and the migration and invasion of tumor cells

Metastasis is characterized pathologically by uncontrolled cell invasion, proliferation, migration and angiogenesis. It is a multistep process that encompasses the modulation of membrane permeability and invasion, cell spreading, cell migration and proliferation of the extracellular matrix, increase in cell adhesion molecules and interaction, decrease in cell attachment and induced survival signals and propagation of nutrient supplies (blood vessels). In cancer, a solid tumor cannot expand and spread without a series of synchronized events. Changes in cell adhesion receptor molecules (e.g., integrins, cadherin-catenins) and protease expressions have been linked to tumor invasion and metastasis. It has also been determined that ligand-growth factor receptor interactions have been associated with cancer development and metastasis via the endocytic pathway. Specifically, growth factors, which include IGF-1 and IGF-2 therapy, have been associated with most if not all of the features of metastasis. In this review, we will revisit some of the key findings on perhaps one of the most important hallmarks of cancer metastasis: cell migration and cell invasion and the role of the endocytic pathway in mediating this phenomenon.

A fresh look at zebrafish from the perspective of cancer research

Zebrafish represent a vertebrate model organism that has been widely, and increasingly, employed over the last decade in the study of developmental processes, wound healing, microbe-host interactions, and drug screening. With the increase in the laboratory use of zebrafish, several advantages, such as a high genetic homology to humans and transparent embryos, which allow clear disease evaluation, have greatly widened its use as a model for studying tumor development in vivo. The use of zebrafish has been applied in several areas of cancer research, mainly in the following domains: (1) establishing cancer models by carcinogenic chemical, genetic technology, and xenotransplantation; (2) evaluating tumor angiogenesis; (3) studying tumor metastasis; and (4) anti-tumor drug screening and drug toxicity evaluation. In this study, we provide a comprehensive overview of the role of zebrafish in order to underline the advantages of using them as a model organism in cancer research. Several related successful events are also reviewed.

Tumor Suppressor WWOX inhibits osteosarcoma metastasis by modulating RUNX2 function

Osteosarcoma (OS) is among the most frequently occurring primary bone tumors, primarily affecting adolescents and young adults. This malignant osteoid forming tumor is characterized by its metastatic potential, mainly to lungs. We recently demonstrated that WW domain-containing oxidoreductase (WWOX) is frequently inactivated in human OS and that WWOX restoration in WWOX-negative OS cells suppresses tumorigenicity. Of note, WWOX levels are reduced in paired OS samples of post-treatment metastastectomies as compared to pre-treatment biopsies suggesting that decreased WWOX levels are associated with a more aggressive phenotype at the metastatic site. Nevertheless, little is known about WWOX function in OS metastasis. Here, we investigated the role of tumor suppressor WWOX in suppressing pulmonary OS metastasis bothin vitroandin vivo. We demonstrated that ectopic expression of WWOX in OS cells, HOS and LM-7, inhibits OS invasion and cell migration in vitro. Furthermore, WWOX expression reduced tumor burden in vivo and inhibited metastases’ seeding and colonization. Mechanistically, WWOX function is associated with reduced levels of RUNX2 metastatic target genes implicated in adhesion and motility. Our results suggest that WWOX plays a critical role in determining the aggressive phenotype of OS, and its expression could be an attractive therapeutic target to combat this devastating adolescent disease.

P2Y2R activation by nucleotides released from the highly metastatic breast cancer cell MDA-MB-231 contributes to pre-metastatic niche formation by mediating lysyl oxidase secretion, collagen crosslinking, and monocyte recruitment

Tumor microenvironmental hypoxia induces hypoxia inducible factor-1α (HIF-1α) overexpression, leading to the release of lysyl oxidase (LOX), which crosslinks collagen at distant sites to facilitate environmental changes that allow cancer cells to easily metastasize. Our previous study showed that activation of the P2Y2 receptor (P2Y2R) by ATP released from MDA-MB-231 cells increased MDA-MB-231 cell invasion through endothelial cells. Therefore, in this study, we investigated the role of P2Y2R in breast cancer cell metastasis to distant sites. ATP or UTP released from hypoxia-treated MDA-MB-231 cells induced HIF-1α expression and LOX secretion by the activation of P2Y2R, and this phenomenon was significantly reduced in P2Y2R-depleted MDA-MB-231 cells. Furthermore, P2Y2R-mediated LOX release induced collagen crosslinking in an in vitro model. Finally, nude mice injected with MDA-MB-231 cells showed high levels of LOX secretion, crosslinked collagen and CD11b+ BMDC recruitment in the lung; however, mice that were injected with P2Y2R-depleted MDA-MB-231 cells did not exhibit these changes. These results demonstrate that P2Y2R plays an important role in activation of the HIF-1α-LOX axis, the induction of collagen crosslinking and the recruitment of CD11b+ BMDCs. Furthermore, P2Y2R activation by nucleotides recruits THP-1 monocytes, resulting in primary tumor progression and pre-metastatic niche formation.

Bone Sarcomas in Pediatrics: Progress in Our Understanding of Tumor Biology and Implications for Therapy

The pediatric bone sarcomas osteosarcoma and Ewing sarcoma represent a tremendous challenge for the clinician. Though less common than acute lymphoblastic leukemia or brain tumors, these aggressive cancers account for a disproportionate amount of the cancer morbidity and mortality in children, and have seen few advances in survival in the past decade, despite many large, complicated, and expensive trials of various chemotherapy combinations. To improve the outcomes of children with bone sarcomas, a better understanding of the biology of these cancers is needed, together with informed use of targeted therapies that exploit the unique biology of each disease. Here we summarize the current state of knowledge regarding the contribution of receptor tyrosine kinases, intracellular signaling pathways, bone biology and physiology, the immune system, and the tumor microenvironment in promoting and maintaining the malignant phenotype. These observations are coupled with a review of the therapies that target each of these mechanisms, focusing on recent or ongoing clinical trials if such information is available. It is our hope that, by better understanding the biology of osteosarcoma and Ewing sarcoma, rational combination therapies can be designed and systematically tested, leading to improved outcomes for a group of children who desperately need them.

Histogram Analysis of CT Perfusion of Hepatocellular Carcinoma for Predicting Response to Transarterial Radioembolization: Value of Tumor Heterogeneity Assessment

PURPOSE

To evaluate in patients with hepatocellular carcinoma (HCC), whether assessment of tumor heterogeneity by histogram analysis of computed tomography (CT) perfusion helps predicting response to transarterial radioembolization (TARE).

MATERIALS AND METHODS

Sixteen patients (15 male; mean age 65 years; age range 47-80 years) with HCC underwent CT liver perfusion for treatment planning prior to TARE with Yttrium-90 microspheres. Arterial perfusion (AP) derived from CT perfusion was measured in the entire tumor volume, and heterogeneity was analyzed voxel-wise by histogram analysis. Response to TARE was evaluated on follow-up imaging (median follow-up, 129 days) based on modified Response Evaluation Criteria in Solid Tumors (mRECIST). Results of histogram analysis and mean AP values of the tumor were compared between responders and non-responders. Receiver operating characteristics were calculated to determine the parameters' ability to discriminate responders from non-responders.

RESULTS

According to mRECIST, 8 patients (50%) were responders and 8 (50%) non-responders. Comparing responders and non-responders, the 50th and 75th percentile of AP derived from histogram analysis was significantly different [AP 43.8/54.3 vs. 27.6/34.3 mL min(-1) 100 mL(-1)); p < 0.05], while the mean AP of HCCs (43.5 vs. 27.9 mL min(-1) 100 mL(-1); p > 0.05) was not. Further heterogeneity parameters from histogram analysis (skewness, coefficient of variation, and 25th percentile) did not differ between responders and non-responders (p > 0.05). If the cut-off for the 75th percentile was set to an AP of 37.5 mL min(-1) 100 mL(-1), therapy response could be predicted with a sensitivity of 88% (7/8) and specificity of 75% (6/8).

CONCLUSION

Voxel-wise histogram analysis of pretreatment CT perfusion indicating tumor heterogeneity of HCC improves the pretreatment prediction of response to TARE.

The S100P/RAGE signaling pathway regulates expression of microRNA-21 in colon cancer cells

S100P signaling through the receptor for advanced glycation end-products (RAGE) contributes to colon cancer invasion and metastasis, but the mechanistic features of this process are obscure. Here, we investigate whether activation of S100P/RAGE signaling regulates oncogenic microRNA-21 (miR-21). We show that exogenous S100P up-regulates miR-21 levels in human colon cancer cells, whereas knockdown of S100P results in a decrease of miR-21. Furthermore, blockage of RAGE with anti-RAGE antibody suppresses S100P induction of miR-21. In addition, we found that S100P induction of miR-21 expression involves ERK and is suppressed by the MEK inhibitor U0126. Also, S100P treatment stimulates the enrichment of c-Fos, and AP-1 family members, at the miR-21 gene promoter.

Netrin-1 as a potential target for metastatic cancer: focus on colorectal cancer

Despite advanced screening technology and cancer treatments available today, metastasis remains an ongoing major cause of cancer-related deaths worldwide. Typically, colorectal cancer is one of the cancers treatable by surgery in conjunction with chemotherapy when it is detected at an early stage. However, it still ranks as the second highest modality and mortality of cancer types in western countries, and this is mostly due to a recurrence of metastatic colorectal cancer post-resection of the primary malignancy. Colorectal cancer metastases predominantly occur in the liver and lung, and yet the molecular mechanisms that regulate these organ-specific colorectal cancer metastases are largely unknown. Therefore, the identification of any critical molecule, which triggers malignancy in colorectal cancer, would be an excellent target for treatment. Netrin-1 was initially discovered as a chemotropic neuronal guidance molecule, and has been marked as a regulator for many cancers including colorectal cancer. Here, we summarise key findings of the role of netrin-1 intrinsic to colorectal cancer cells, extrinsic to the tumour microenvironment and angiogenesis, and consequently, we evaluate netrin-1 as a potential target molecule for metastasis.

Frequent expression of PD-L1 on circulating breast cancer cells

Immune checkpoint regulators such as PD-L1 have become exciting new therapeutic targets leading to long lasting remissions in patients with advanced malignancies. However, in view of the remarkable costs and the toxicity profiles of these therapies, predictive biomarkers able to discriminate responders from non-responders are urgently needed. In the present paper, we provide evidence that PD-L1 is frequently expressed on metastatic cells circulating in the blood of hormone receptor-positive, HER2-negative breast cancer patients. We performed western blot, flow cytometry and immunocytochemical analyses to demonstrate the specificity of the PDL1 antibody used in our study and established immunoscores for PDL1 expression on single tumor cells. We then selected sixteen patients with circulating tumor cells (CTCs) using the CellSearch(®) system and found PD-L1((+)) CTCs in 11 patients (68.8%). The fraction of PD-L1((+)) CTCs varied from 0.2 to 100% in individual patients. This is the first report demonstrating the expression of PD-L1 on CTCs. The established CTC/PD-L1 assay can be used for liquid biopsy in future clinical trials for stratification and monitoring of cancer patients undergoing immune checkpoint blockade.