Metastatic Nature Research Articles

Metastasis of Renal Clear Cell Carcinoma to the Oral Cavity

Metastasis of renal clear cell carcinoma to the head and neck region is uncommon, and the involvement of the oral cavity is even rarer. In this report, we describe a new case affecting an 82-year-old man, with a past medical history positive for renal cell carcinoma in the left kidney, which was removed by partial nephrectomy. After 2 years of follow-up, a positron emission tomography exam and computed tomography exam confirmed a local recurrence, and the patient underwent chemotherapy; however, other metastatic foci were later identified in the head and neck region after 10 months of follow-up. The patient was then referred to our oral medicine service due to a reddish, painless nodule in the soft palate. An excisional biopsy was conducted and revealed the presence of clear cells organized in an alveolar pattern, confirming the metastatic nature of the lesion. Currently, the patient is under palliative treatment, with no evidence of oral lesions.

Aberrant expression of PDZ-binding kinase/T-LAK cell-originated protein kinase modulates the invasive ability of human pancreatic cancer cells via the stabilization of oncoprotein c-MYC.

High frequency of mortality in patients with pancreatic ductal adenocarcinoma (PDAC) is vastly associated with the invasive and metastatic nature of these cancer cells. Little is known about the factors involved in this invasive/metastatic process. The current challenge in the treatment of these patients is the lack of viable options besides gemcitabine. The aim of this study was to evaluate the role of PDZ-binding kinase (PBK)/T-LAK cell-originated protein kinase (TOPK) in invasive PDAC cells and to determine whether PBK/TOPK expression drives invasiveness in PDAC. Using gain-of-function and loss-of-function studies in established and patient-derived xenograft-PDAC cell lines, and examining patient-derived archival tissue samples, we demonstrate for the first time that PBK/TOPK is upregulated in pancreatic cancer and expression levels are closely associated with the invasive property of pancreatic cancer cells. Modulation of PBK/TOPK causally regulates the invasive ability of PDAC cells. We also demonstrate that two key players in metastatic invasion, matrix metalloproteinases-2 (MMP-2) and MMP-9 gelatinase activity and gene promoter activities, are regulated by PBK/TOPK. Moreover, we demonstrate for the first time that PBK/TOPK provides stability of an oncoprotein, c-MYC, which transcriptionally regulates MMP-2 and MMP-9 in these invasive PDAC cells. Our in vitro and in situ data corroborate that PBK/TOPK is closely associated with the invasive nature of PDAC and reveal a novel mechanism by which the metastatic behavior of human pancreatic cancer cells is regulated. These findings provide a rationale for targeting PBK/TOPK for the therapeutic intervention of invasive/metastatic pancreatic cancer in human.

Pancreatic cancer stem cells: A state or an entity?

Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, has a median overall survival of 6-12 months and a 5-year survival of less than 7%. While PDAC currently represents the 4th most frequent cause of death due to cancer worldwide, it is expected to become the second leading cause of cancer-related death by 2030. These alarming statistics are primarily due to both the inherent chemoresistant and metastatic nature of this tumor, and the existence of a subpopulation of highly plastic "stem"-like cells within the tumor, known as cancer stem cells (CSCs). Since their discovery in PDAC in 2007, we have come to realize that pancreatic CSCs have unique metabolic, autophagic, invasive, and chemoresistance properties that allow them to continuously self-renew and escape chemo-therapeutic elimination. More importantly, the concept of the CSC as a fixed entity within the tumor has also evolved, and current data suggest that CSCs are states rather than defined entities. Consequently, current treatments for the majority of PDAC patients are not effective, and do not significantly impact overall patient survival, as they do not adequately target the plastic CSC sub-population nor the transient/hybrid cells that can replenish the CSC pool. Thus, it is necessary that we improve our understanding of the characteristics and signals that maintain and drive the pancreatic CSC population in order to develop new therapies to target these cells. Herein, we will provide the latest updates and knowledge on the inherent characteristics of pancreatic CSCs and the CSC niche, specifically the cross-talk that exists between CSCs and niche resident cells. Lastly, we will address the question of whether a CSC is a state or an entity and discuss how the answer to this question can impact treatment approaches.

The Highly Metastatic Nature of Uterine Cervical/Endometrial Cancer Displaying Tumor-Related Leukocytosis: Clinical and Preclinical Investigations.

Purpose: The aim of this study was to investigate the metastatic potential of uterine cervical and endometrial cancer displaying tumor-related leukocytosis (TRL).Experimental Design: Clinical data on uterine cervical (N = 732) and endometrial cancer (N = 900) were collected, and the metastatic potential of TRL-positive cancer was evaluated in univariate and multivariate analyses. Tumor and blood samples obtained from patients with cervical cancer, cervical cancer cell lines, and a mouse model of cervical cancer were used to examine the mechanisms underlying the highly metastatic nature of TRL-positive cancer, focusing on tumor-derived G-CSF and the myeloid-derived suppressor cell (MDSC)-mediated premetastatic niche.Results: Pretreatment TRL was significantly associated with visceral organ metastasis in patients with uterine cervical or endometrial cancer. The patients with TRL-positive cervical cancer displayed upregulated tumor G-CSF expression, elevated G-CSF levels, and increased MDSC frequencies in the peripheral blood compared with the TRL-negative patients. In vitro and in vivo investigations revealed that MDSCs produced in response to tumor-derived G-CSF are involved in premetastatic niche formation, which promotes visceral organ metastasis of TRL-positive cancer. The depletion of MDSCs attenuated this premetastatic niche formation and effectively inhibited the visceral organ metastasis of TRL-positive cancer.Conclusions: Uterine cervical/endometrial cancer displaying TRL is a distinct clinical entity with high metastatic potential. Tumor-derived G-CSF and the MDSC-mediated premetastatic niche are responsible for the highly metastatic nature of this type of cancer. MDSC-targeting therapy might represent a potential strategy for combating metastasis derived from TRL-positive uterine cancer. Clin Cancer Res; 24(16); 4018-29. ©2018 AACR.

Predictors of skeletal-related events among cancer patients with bone metastases treated with zoledronic acid: a secondary analysis of a randomized study

ABSTRACTBackground: The purpose of the current study is to assess the predictors of skeletal-related events (SREs) among advanced cancer patients with bone metastases treated with zoledronic acid within a randomized study.Research design and methods: This is a secondary analysis of patient-level data of advanced cancer patients with bone metastases who were treated with monthly zoledronic acid in the NCT00330759 clinical trial.Results: A total of 702 patients were included in the current analysis. In univariate logistic regression analysis, higher body mass index (P = 0.034) and lytic nature of bone metastasis (P = 0.008) were found to be predictive of a higher probability of SREs. When the two factors were included in a multivariate logistic regression model, both of them were predictive of the later development of SREs (P value for higher body mass index = 0.015; P value for lytic bone lesions = 0.005).Conclusion: Among advanced cancer patients with bone metastases, lytic nature of metastases, as well as higher body mass index, are associated with a higher probability of SREs.Trial registration number: this clinical trial was registered at clinicaltrials.gov with the number: nct0033

Flubendazole elicits anti-metastatic effects in triple-negative breast cancer via STAT3 inhibition.

Tumor metastasis remains the cause of 90% of cancer-related deaths. Cancer stem cells (CSC) are thought to be responsible for the aggressive and metastatic nature of triple-negative breast cancers (TNBC), and new therapeutic strategies are being devised to target them. Flubendazole (FLU) is a widely used anthelmintic agent that also exhibits anticancer activity in several cancer types. The aim of this study was to characterize the mechanism of action of FLU on breast cancer stem cell (BCSC)-like properties and metastasis in TNBC. FLU treatment caused a significant induction of apoptosis, accompanied by G2/M phase accumulation, caspase-3/-7 activation and the dysregulation of STAT3 activation in TNBC cells. The latter phenomenon was associated with impairment of cancer stem-like traits, concomitant with a reduction in the CD24low /CD44high , CD24high /CD49fhigh subpopulation, ALDH1 activity and mammosphere formation. The BCSC-enriched populations exhibited enhanced metastasis with higher STAT3 activation, while FLU administration inhibited tumor growth, angiogenesis and lung and liver metastasis, coinciding with decreased MMP-2 and MMP-9 levels in circulating blood. FLU kills not only rapid proliferating tumor cells but also effectively eradicates BCSC-like cells in vitro and in vivo. Our findings warrant further investigation of FLU as a treatment for metastatic TNBC.

Abstract 1112: AKT2 loss impairs BRAF mutant melanoma metastasis

Abstract Despite recent advances in treatment, melanoma remains the deadliest form of skin cancer, due to its highly metastatic nature. Many melanomas with oncogenic BRAFV600E lose the tumor suppressor PTEN, leading to unconstrained PI3K/AKT signaling and a drastic increase in melanoma invasiveness, but the contribution of AKT to melanoma metastasis has not been fully explored. Differential roles for AKT1 and AKT3 have been suggested in many cancers, but a requirement for AKT2 has not been described in melanoma. We report here that shRNA-mediated, conditional knockdown of AKTs in a variety of human melanoma cell lines reveals that selective AKT2 depletion inhibits migratory and invasive phenotypes in vitro, and prevents metastasis in vivo. Our results support a critical role for AKT2 in stimulating melanoma cell migration and invasion and in supporting growth of metastatic lesions. As AKT inhibitors advance in clinical trials for melanoma, our findings could inform therapeutic strategies to improve treatment options and outcome for this devastating disease. Citation Format: Siobhan K. McRee, Jodie R. Pietruska, Philip N. Tsichlis, Phil W. Hinds. AKT2 loss impairs BRAF mutant melanoma metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1112.

Heparan sulfate proteoglycans undergo differential expression alterations in left sided colorectal cancer, depending on their metastatic character

BackgroundHeparan sulfate proteoglycans (HSPGs) are complex molecules which play a role in the invasion and growth and metastatic properties of cancerous cells. In this work we analyze changes in the patterns of expression of HSPGs in left sided colorectal cancer (LSCRC), both metastatic and non-metastatic, and the results are also compared with those previously obtained for right sided tumors (RSCRCs).MethodsEighteen LSCRCs were studied using qPCR to analyze the expression of both the proteoglycan core proteins and the enzymes involved in heparan sulfate chain biosynthesis. Certain HSPGs also carry chondroitin sulfate chains and so we also studied the genes involved in its biosynthesis. The expression of certain genes that showed significant expression differences were also analysed using immunohistochemical techniques.ResultsChanges in proteoglycan core proteins were dependent on their location, and the main differences between metastatic and non-metastatic tumors affected cell-surface glypicans, while other molecules were quite similar. Glypicans were also responsible for the main differences between RS- and LS- malignances. Regarding the biosynthesis of heparan sulfate chains, differential alterations in transcription depending on the presence or not of metastasis affected genes involved in the modification of uronic acid (epimerization and 2-O sulfation), and some isoforms responsible for sulfation of glucosamine (NDST1, HS6ST1). Moreover, in RSCRCs differences were preferentially found in the expression of genes involved in C6 and C3 sulfation of glucosamine, but not in NDSTs or SULFs. Finally, synthesis of chondroitin sulfate showed some alterations, which affected various steps, including polimerization and the modification of chains, but the main variations dependent on the presence of metastases were epimerization and 6C sulfation; however, when compared with RSCRCs, the essential divergences affected polymerization of the chains and the 6C sulfation of the galactosamine residue.ConclusionsWe evidenced alterations in the expression of HSPGs, including the expression of cell surface core proteins, many glycosiltransferases and some enzymes that modify the GAG chains in LSCRCs, but this was dependent on the metastatic nature of the tumor. Some of these alterations are shared with RSCRCs, while others, focused on specific gene groups, are dependent on tumor localization.

Evaluation of Skeletal Hot Spots in Carcinoma Prostate Patients by Scintimetric Method

<p>Skeletal scintigraphy is a highly sensitive tool in the detection of metastatic disease from prostate cancer, but its specificity is relatively low. Various quantitative parameters have been introduced to improve the bone scan specificity. Scintimetric method based Dr. V. Siva’s retention ratio is one such parameter proposed to help in predicting malignant or metastatic nature of the skeletal hot spots in a bone scan non-invasively. This study was performed to evaluate the V. Siva’s ratio in a small sample of prostate cancer patients in Bangladeshi population. This prospective observational study was carried out at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS) from July 2015 to June 2016. A total of 32 patients with diagnosed prostate cancer were enrolled. Each patient underwent two bone scans at 4 hours and 24 hours respectively after radiopharmaceutical injection. Focal hot spots reported by expert Nuclear Medicine specialists were identified in both scans and maximum counts were taken by drawing region of interest over the spots. Dr. V. Siva’s retention ratio was calculated by dividing the 4-hour count with 24-hour count. Finally statistical analysis was done. The mean V. Siva's ratio of metastatic group was 9.3 ± 2.2 (95% CI 8.5-10.1) and that of degenerative group was 8.2 ± 2.0 (95% CI 7.5-8.9). Statistically significant difference was observed between the two groups. So it can be said that V. Siva’s retention ratio might be useful as a quantitative parameter in adjunct to conventional bone scintigraphy for the skeletal survey of carcinoma prostate patients.</p><p>Bangladesh J. Nuclear Med. 20(1): 9-13, January 2017</p>

Distant Metastasis from Benign Phyllodes Tumor

Objective: As there is a dearth of information on phyllodes tumors of the breast in the Philippines yet this ultimately impacts on the management and survival of Filipino patients, the authors reviewed their surgical cases of phyllodes tumors, focusing in this report, for the first time in Philippine literature, on the real risk of distant metastasis from the more common benign variety of phyllodes tumors. They therefore aim to identify case/s and do a review of literature on distant metastasis from benign phyllodes tumors. Methods: A review of records of all surgical cases of phyllodes tumor managed at PGH from 2005 – 2014 was done. Data from patients who on follow up were found to have distant metastasis were gathered and further reviewed. A literature search on metastatic phyllodes tumor and its implications was likewise done to complete this study. Results: A total of 200 patients with phyllodes tumor surgically managed within the study period were reviewed and followed up. One hundred sixty one out of 200 (80.5%) patients were histologically classified as benign. Twelve patients out of 200 (6.0%) developed distant metastasis on follow up, 1 (0.62% of 161 benign phyllodes tumors) of whom had benign phyllodes tumor. Conclusion: The authors show that distant metastasis from benign phyllodes tumor can occur here in the Philippines. Therefore, the subtype of phyllodes tumor alone, especially in benign lesions, does not absolutely predict biological behavior and risk of recurrence. A better understanding of the true nature of metastasis in these tumors is highly anticipated. Key words: Breast surgery, Phyllodes, metastasis, benign

Primary Hepatic Angiosarcoma: A Brief Review of the Literature

Primary hepatic angiosarcoma (HAS) is a liver tumour of endothelial cell origin. It is the most common malignant mesenchymal tumour of the liver, but is nonetheless rare, accounting for approximately 0.1–2.0% of all primary liver malignancies. Historically, 25% of HAS cases were associated with occupational or medicinal exposure, but most cases are now considered idiopathic. Patients present with vague signs and symptoms of liver disease, often resulting in late diagnoses; patients may present with acute liver failure or spontaneous rupture of the tumour, but this is rare. Preoperative diagnosis of HAS is difficult because laboratory and radiological findings are often non-specific or unable to discern malignant masses from benign growths. Obtaining a biopsy for histopathological diagnosis of HAS is also difficult because of its vascular and haemorrhagic nature, and reports of death from closed biopsies have been noted. Prognosis is poor because of the disease’s diagnostic challenges and the tumour’s rapidly progressive and early metastatic nature. The reported median survival is approximately 6 months, with only 3% of patients living >2 years. This paper will review and summarise new and existing publications in the English language literature to provide a better understanding of the challenges posed by HAS.

CTHRC1 induces non-small cell lung cancer (NSCLC) invasion through upregulating MMP-7/MMP-9

BackgroundThe strong invasive and metastatic nature of non-small cell lung cancer (NSCLC) leads to poor prognosis. Collagen triple helix repeat containing 1 (CTHRC1) is involved in cell migration, motility and invasion. The object of this study is to investigate the involvement of CTHRC1 in NSCLC invasion and metastasis.MethodsA proteomic analysis was performed to identify the different expression proteins between NSCLC and normal tissues. Cell lines stably express CTHRC1, MMP7, MMP9 were established. Invasion and migration were determined by scratch and transwell assays respectively. Clinical correlations of CTHRC1 in a cohort of 230 NSCLC patients were analysed.ResultsCTHRC1 is overexpressed in NSCLC as measured by proteomic analysis. Additionally, CTHRC1 increases tumour cell migration and invasion in vitro. Furthermore, CTHRC1 expression is significantly correlated with matrix metalloproteinase (MMP)7 and MMP9 expression in sera and tumour tissues from NSCLC. The invasion ability mediated by CTHRC1 were mainly MMP7- and MMP9-dependent. MMP7 or MMP9 depletion significantly eradicated the pro-invasive effects mediated by CTHRC1 on NSCLC cells. Clinically, patients with high CTHRC1 expression had poor survival.ConclusionsCTHRC1 serves as a pro-metastatic gene that contributes to NSCLC invasion and metastasis, which are mediated by upregulated MMP7 and MMP9 expression. Targeting CTHRC1 may be beneficial for inhibiting NSCLC metastasis.

TRIM59 induces epithelial-to-mesenchymal transition and promotes migration and invasion by PI3K/AKT signaling pathway in medulloblastoma.

Medulloblastoma is the most common malignant brain tumor in children. Despite remarkable advances over previous decades, the long-term survival of patients with medulloblastoma remains poor due to the frequent metastatic nature of this malignancy. The aim of the present study was to examine the role of tripartite motif containing 59 (TRIM59) in cell metastasis in medulloblastoma. It was initially demonstrated that TRIM59 expression was significantly increased in clinical medulloblastoma tissues compared with adjacent non-cancerous tissues and differentially expressed in a series of medulloblastoma cell lines. The knockdown of TRIM59 in D283 cells resulted in epithelial-to-mesenchymal transition (EMT), and decreased cell migratory and invasive capacities. By contrast, the overexpression of TRIM59 in Daoy cells was able to inhibit the EMT process and increase migratory and invasive capacities of the cells. Notably, the knockdown of TRIM59 was able to decrease the protein level of matrix metalloproteinase (MMP)-2 without altering the levels of MMP-9, and conversely the overexpression of TRIM59 was able to increase the protein level of MMP-2. Importantly, the downregulation of TRIM59 in D283 cells was able to inhibit the levels of phosphorylated (p)-AKT (Ser473), glycogen synthase kinase 3 β(GSK3β; Ser9) and phosphoinositide 3-kinase (PI3K) p85 (Tyr458) without altering the levels of total protein. The data from the present study suggest that TRIM59 induces epithelial-to-mesenchymal transition and promotes migration and invasion by PI3K/AKT signaling pathway in medulloblastoma. This data may provide novel insight into tumor metastasis and pave the way for the development of therapeutic strategies for the treatment of medulloblastoma in the clinic.

Effects of Low- and High-Dose Chemotherapy Agents on Thrombogenic Properties of Extracellular Vesicles Derived from Breast Cancer Cell Lines.

The involvement of extracellular vesicles (EVs) in cancer-associated thrombosis (CT) is unclear. This study aimed to explore the properties of EVs derived from breast cancer (BC) cells following exposure to high- or low-dose chemotherapeutic agents and evaluate thrombogenic effects of these EVs on endothelial cells (ECs). EVs were isolated from BC cell lines (non-metastatic MCF7, high-metastatic MDA-MB-231), pre-exposed to serum-free medium (control), with or without increasing doses of doxorubicin or paclitaxel. EV structure and size were studied using electron microscopy and Nano-sight. Antigen levels were measured by fluorescence-activated cell sorting (FACS). EV effects on EC thrombogenicity were assessed using FACS, factor Xa chromogenic assay and RT-PCR. Serum-free medium BC cell resulted in EV shedding that additionally increased when MDA-MB-231 cells were exposed to high doses of both agents. Tissue factor (TF) levels were similarly low (9-13%) in all EVs compared with the high expression on their parental MDA-MB-231 cells (76-83%). EVs derived from MDA-MB-231 cells stimulated with high-dose doxorubicin demonstrated significantly (fivefold; p < 0.001) elevated levels of negatively charged phospholipids, a 97% decrease in TF pathway inhibitor (TFPI) levels and a sixfold increase (p < 0.001) in procoagulant activity. These EVs also enhanced EC thrombogenicity. Effects of EVs originating from MCF7 cells were less pronounced. These findings suggest that thrombogenic properties of BC-derived EVs may depend on the type and dose of the applied chemotherapy agent and may also be affected by the cell metastatic nature.

THE EVALUATION OF DELAYED ENHANCEMENT METHOD AS A TOOL FOR MAGNETIC RESONANCE DIFFERENTIATION BETWEEN THE METASTASES AND NEUROTOXOPLASMOSIS

The aimof this study was to evaluate delayed enhancement as the tool for differentiation between metastatic brain lesions and neurotoxoplasmosis.Materials and methods.38 patients with multiple brain lesions with mass-effect and ring-type of contrast enhancement based on CT/MRI have been enrolled in the study. All cases were associated with metastatic brain lesions or toxoplasmosis. For every patient we performed contrast enhanced brain MRI and achieved axial T1WI immediately after contrast injection, in 15, 30 and 45 min. Acquired images were evaluated for the presence of contrast accumulation at delayed images in the central part of the lesions. Overall, we analyzed data for 153 lesions with 64 toxoplasmosis lesions and 89 metastatic.Results.Among 153 lesions with ring-type contrast enhancement central contrast enhancement at delayed images was determined for 83 lesions. Among 89 metastatic lesions 81 demonstrated delayed central enhancement. Among 64 neurotoxoplasmosis lesions only 2 demonstrated delayed central enhancement. The sensitivity of the sign was 88%, specificity 95%.Conclusions.The presence of central contrast enhancement at delayed images significantly increases the probability of metastatic nature of the lesions (specificity 95%). Consequently that sign might be effectively used for the differential between the metastases and neurotoxoplasmosis.

Abl and Arg mediate cysteine cathepsin secretion to facilitate melanoma invasion and metastasis.

The incidence of melanoma is increasing, particularly in young women, and the disease remains incurable for many because of its aggressive, metastatic nature and its high rate of resistance to conventional, targeted, and immunological agents. Cathepsins are proteases that are critical for melanoma progression and therapeutic resistance. Intracellular cathepsins cleave or degrade proteins that restrict cancer progression, whereas extracellular cathepsins directly cleave the extracellular matrix and activate proinvasive proteases in the tumor microenvironment. Cathepsin secretion is markedly increased in cancer cells. We investigated the signaling pathways leading to increased cathepsin secretion in melanoma cells. We found that the nonreceptor tyrosine kinases Abl and Arg (Abl/Arg) promoted the secretion of cathepsin B and cathepsin L by activating transcription factors (namely, Ets1, Sp1, and NF-κB/p65) that have key roles in the epithelial-mesenchymal transition (EMT), invasion, and therapeutic resistance. In some melanoma cell lines, Abl/Arg promoted the Ets1/p65-induced secretion of cathepsin B and cathepsin L in a kinase-independent manner, whereas in other melanoma lines, Abl/Arg promoted the kinase-dependent, Sp1/Ets1/p65-mediated induction of cathepsin L secretion and the Sp1/p65-mediated induction of cathepsin B secretion. As an indication of clinical relevance, the abundance of mRNAs encoding Abl/Arg, Sp1, Ets1, and cathepsins was positively correlated in primary melanomas, and Abl/Arg-driven invasion in culture and metastasis in vivo required cathepsin secretion. These data suggest that drugs targeting Abl kinases, many of which are FDA-approved, might inhibit cathepsin secretion in some melanomas and potentially other aggressive cancers harboring activated Abl kinases.

CCR5/CCL5 axis interaction promotes migratory and invasiveness of pancreatic cancer cells

Pancreatic cancer (PC) is one of the deadliest cancers and remains a major challenge due to its invasive and metastatic nature. Increased levels of CCR5 and CCL5 have established indicators for disease status in various cancers, including PC. However, their role in invasion and metastasis of PC is not known. Here we conducted immunohistochemistry of PC tissues and found elevated epithelial staining for CCR5 and CCL5 in metastatic PC tissues compared to non-neoplastic. In vitro experiments, such as flow cytometry, immunofluorescence and western blotting with human PC cell lines (AsPc-1, BxPc-3 and MIA PaCa-2), showed higher expression levels of CCR5. The CCL5 activation of PC cells expressing CCR5 increased their invasive potential, while treatment with CCR5 inhibitor maraviroc inhibited the CCL5 activation. CCL5 induced proliferation of PC cells was mediated through F-actin polymerization, while there was marked reduction when the cells were treated with maraviroc. The direct interaction of CCR5 with CCL5 was verified using a calcium mobilization assay. Taken together, our results demonstrate that CCR5 and CCL5 are potential markers for metastatic PC cancer, and their interaction leads to the increased PC cell invasion. Thus, blocking CCR5/CCL5 axis might prove beneficial to prevent metastasis and provide a more therapeutic strategy to control PC progression.

Merkel Cell Polyomavirus Small T Antigen Drives Cell Motility via Rho-GTPase-Induced Filopodium Formation.

ABSTRACTCell motility and migration is a complex, multistep, and multicomponent process intrinsic to progression and metastasis. Motility is dependent on the activities of integrin receptors and Rho family GTPases, resulting in the remodeling of the actin cytoskeleton and formation of various motile actin-based protrusions. Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high likelihood of recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is associated with the majority of MCC cases, and MCPyV-induced tumorigenesis largely depends on the expression of the small tumor antigen (ST). Since the discovery of MCPyV, a number of mechanisms have been suggested to account for replication and tumorigenesis, but to date, little is known about potential links between MCPyV T antigen expression and the metastatic nature of MCC. Previously, we described the action of MCPyV ST on the microtubule network and how it impacts cell motility and migration. Here, we demonstrate that MCPyV ST affects the actin cytoskeleton to promote the formation of filopodia through a mechanism involving the catalytic subunit of protein phosphatase 4 (PP4C). We also show that MCPyV ST-induced cell motility is dependent upon the activities of the Rho family GTPases Cdc42 and RhoA. In addition, our results indicate that the MCPyV ST-PP4C interaction results in the dephosphorylation of β1 integrin, likely driving the cell motility pathway. These findings describe a novel mechanism by which a tumor virus induces cell motility, which may ultimately lead to cancer metastasis, and provides opportunities and strategies for targeted interventions for disseminated MCC.IMPORTANCE Merkel cell polyomavirus (MCPyV) is the most recently discovered human tumor virus. It causes the majority of cases of Merkel cell carcinoma (MCC), an aggressive skin cancer. However, the molecular mechanisms implicating MCPyV-encoded proteins in cancer development are yet to be fully elucidated. This study builds upon our previous observations, which demonstrated that the MCPyV ST antigen enhances cell motility, providing a potential link between MCPyV protein expression and the highly metastatic nature of MCC. Here, we show that MCPyV ST remodels the actin cytoskeleton, promoting the formation of filopodia, which is essential for MCPyV ST-induced cell motility, and we also implicate the activity of specific Rho family GTPases, Cdc42 and RhoA, in these processes. Moreover, we describe a novel mechanism for the activation of Rho-GTPases and the cell motility pathway due to the interaction between MCPyV ST and the cellular phosphatase catalytic subunit PP4C, which leads to the specific dephosphorylation of β1 integrin. These findings may therefore provide novel strategies for therapeutic intervention for disseminated MCC.

Cholecystokinin Receptor-Targeted Polyplex Nanoparticle Inhibits Growth and Metastasis of Pancreatic Cancer.

Background & AimsPancreatic ductal adenocarcinoma (PDAC) remains the most aggressive malignancy with the lowest 5-year survival rate of all cancers in part owing to the lack of tumor-specific therapy and the rapid metastatic nature of this cancer. The gastrointestinal peptide gastrin is a trophic peptide that stimulates growth of PDAC in an autocrine fashion by interaction with the cholecystokinin receptor that is overexpressed in this malignancy.MethodsWe developed a therapeutic novel polyplex nanoparticle (NP) that selectively targets the cholecystokinin receptor on PDAC. The NP was characterized in vitro and stability testing was performed in human blood. The effects of the target-specific NP loaded with gastrin small interfering RNA (siRNA) was compared with an untargeted NP and with an NP loaded with a scrambled siRNA in vitro and in 2 orthotopic models of PDAC. A polymerase chain reaction metastasis array examined differentially expressed genes from control tumors compared with tumors of mice treated with the targeted polyplex NP.ResultsThe polyplex NP forms a micelle that safely delivers specific gastrin siRNA to the tumor without off-target toxicity. Consistent with these findings, cellular uptake was confirmed only with the targeted fluorescently labeled NP by confocal microscopy in vitro and by IVIS fluorescent based imaging in mice bearing orthotopic pancreatic cancers but not found with untargeted NPs. Tumor uptake and release of the gastrin siRNA NP was verified by decreased cellular gastrin gene expression by quantitative reverse-transcription polymerase chain reaction and peptide expression by immunohistochemistry. Growth of PDAC was inhibited in a dose-related fashion in cell culture and in vivo. The targeted NP therapy completely blocked tumor metastasis and altered tumor-specific genes.ConclusionsOur polyplex nanoparticle platform establishes both a strong foundation for the development of receptor-targeted therapeutics and a unique approach for the delivery of siRNA in vivo, thus warranting further exploration of this approach in other types of cancers.

Significant value of 18F-FDG-PET/CT in diagnosing small cervical lymph node metastases in patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

BackgroundLittle is known about the nature of metastasis to small cervical lymph nodes (SCLNs) in the patients with nasopharyngeal carcinoma (NPC) examined by using 18-fluoro-2-deoxy-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.MethodsMagnetic resonance images (MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.ResultsIn total, 2082 SCLNs were identified, with 808 (38.8%) ≥ 5 and < 6 mm in diameter (group A), 526 (25.3%) ≥ 6 and < 7 mm in diameter (group B), 374 (18.0%) ≥ 7 and < 8 mm in diameter (group C), 237 (11.4%) ≥ 8 and < 9 mm in diameter (group D), and 137 (6.5%) ≥ 9 and < 10 mm in diameter (group E). The overall metastatic rates examined by using PET/CT for groups A, B, C, D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively (P < 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135 (28.7%) and 46 (9.8%) patients, respectively. The areas under curve of MRI-determined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.ConclusionsPET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.