Radiation-enhanced hepatocellular carcinoma cell invasion with MMP-9 expression through PI3K/Akt/NF-kappaB signal transduction pathway

18F-fluorodeoxyglucose uptake on positron emission tomography as a prognostic predictor in locally advanced hepatocellular carcinoma

BACKGROUND

Metabolic activity assessed by (18)F-fluorodeoxyglocuse-positron emission tomography ((18)F-FDG-PET) reflects biological aggressiveness and prognoses in various tumors. The authors present a correlation between tumor metabolic activity and clinical outcomes in patients with hepatocellular carcinoma (HCC).

METHODS

Over a 3-year period (2005-2008), 135 locally advanced HCC patients were treated with localized concurrent chemoradiotherapy (CCRT; external beam radiotherapy at 45 grays for 5 weeks plus concurrent hepatic arterial infusion of 5-fluorouracil during the first and fifth week) followed by repetitive hepatic arterial infusional chemotherapy with 5-fluorouracil and cisplatin. Among them, the authors studied 107 who received (18)F-FDG-PET before CCRT. Maximal standardized uptake values (SUVs) of tumors were calculated.

RESULTS

The median maximal tumor SUV was 6.1 (range, 2.4-∼19.2). Patients with low maximal tumor SUVs (<6.1) had a higher disease control rate than those with high maximal tumor SUVs (≥6.1) (86.8% vs 68.5%, respectively, P = .023). Both median progression-free survival (PFS; 8.4 vs 5.2 months; P = .003) and overall survival (OS; 17.9 vs 11.3 months; P = .013) were significantly longer in the low maximal tumor SUV group than in the high maximal tumor SUV group, respectively. In multivariate analysis, low maximal tumor SUV and objective responses to CCRT remained significant for PFS and OS. The high maximal tumor SUV group was more likely to have extrahepatic metastasis within 6 months than the low maximal tumor SUV group (58.1% vs 26.8%, respectively; P < .001). Similar results were obtained for the maximal tumor SUV/normal liver maximal SUV ratio (<2 vs ≥2) concerning progression, death, and extrahepatic metastasis.

CONCLUSIONS

Metabolic activity may be useful not only in predicting prognosis and treatment responses, but also in establishing optimal treatment plans in locally advanced HCC.

The synthetic bile acid-phospholipid conjugate ursodeoxycholyl lysophosphatidylethanolamide suppresses TNFα-induced liver injury

BACKGROUND & AIMS

Excessive apoptosis and leukocyte-dependent inflammation mediated by pro-inflammatory cytokines, such as TNFα, are cardinal features of acute liver injury. This study evaluated the ability of the newly designed bile acid-phospholipid conjugate ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE) to protect from hepatocellular injury in comparison to the known hepatoprotectant ursodeoxycholic acid (UDCA) and phosphatidylcholine (PC).

METHODS

Anti-apoptotic and anti-inflammatory properties of UDCA-LPE were evaluated after TNFα treatment of embryonic human hepatocyte cell line CL48 as well as of primary human hepatocytes. Acute liver injury was induced in C57BL/6 mice with d-galactosamine/lipopolysaccharide (GalN/LPS) in order to determine in vivo efficacy of the conjugate.

RESULTS

UDCA-LPE inhibited TNFα-induced apoptosis and inflammation in hepatocytes in vitro and markedly ameliorated GalN/LPS-mediated fulminant hepatitis in mice, whereas UDCA or PC failed to show protection. The conjugate was able to decrease injury-induced elevation of phospholipase A(2) activity as well as its product lysophosphatidylcholine. Analysis of hepatic gene expression showed that UDCA-LPE treatment led to favourable inhibitory effects on expression profiles of key pro-inflammatory cytokines and chemokines, which are crucial for leukocyte recruitment and activation thereby inhibiting chemokine-mediated aggravation of parenchymal damage.

CONCLUSIONS

Thus, UDCA-LPE as a synthetic bile acid-phospholipid conjugate may represent a potent anti-inflammatory agent that is more effective than UDCA and PC for treatment of liver diseases.

Oncogenic role of p53 is suppressed by si-RNA bicistronic construct of uPA, uPAR and cathepsin-B in meningiomas both in vitro and in vivo

Meningiomas are the most commonly occurring intracranial tumors and account for approximately 15-20% of central nervous system tumors. Patients whose tumors recur after surgery and radiation therapy have limited therapeutic options. It has also been reported recently that radiation triggers DNA repair, cell survival and cell proliferation, and reduces apoptosis via the induction of cellular protective mechanisms. Earlier studies have reported that proteases such as uPA, uPAR and cathepsin B play important roles in tumor progression. In the present study, we attempted to determine the effectiveness of two bicistronic siRNA constructs pUC (uPAR/cathepsin B) and pU2 (uPA/uPAR) either alone or in combination with radiation, both in in vitro and in vivo models. Transfection of a plasmid vector expressing double-stranded RNA for uPA, uPAR and cathepsin B significantly induced the sub-G0-G1 cell population by the mitochondrial intrinsic apoptotic pathway. Results showed that pUC efficiently enhanced sub-G0-G1 phases compared to pU2 and was more effective. Interestingly, we observed that in IOMM-Lee cell lines, combined treatment of radiation with pUC and pU2 is more effective in comparison to SF-3061 and MN cell lines. We showed that apoptosis caused by these bicistronic constructs involves Bcl-2, Bcl-xL, p53 inactivation, cytochrome c release from mitochondria and caspase-9 activation, followed by the activation of caspase-3. We also determined that apoptosis caused by pUC and pU2 involves a mechanism which includes inactivation of p53 by its translocation from nucleus to cytoplasm as confirmed by immunofluorescence, which shows the oncogenic potential of p53 in meningiomas. However, the simultaneous RNAi-mediated targeting of uPAR and cathepsin B (pUC), in combination with irradiation, has greater potential application for the treatment of human meningioma in comparison to pU2 by decreasing p53 expression both in vitro and in vivo.

Sonic hedgehog signaling protects human hepatocellular carcinoma cells against ionizing radiation in an autocrine manner

PURPOSE

Sonic hedgehog (Shh) signaling is critical to embryogenesis and resistance to chemotherapy. We aimed to examine the role of Shh signaling in the response to radiation of human hepatocellular carcinoma (HCC) cells.

METHODS AND MATERIALS

Response to ionizing radiation therapy (RT) was evaluated by clonogenic assay. Quantitative RT-polymerase chain reaction for patched-1 (PTCH-1) expression was performed. Cytosolic accumulation of Shh and nuclear translocation of Gli-1 were assessed by immunofluorescence. Gli-1 knockdown was done by RNA interference (RNAi). Immunoprecipitation was performed to detect Shh ligand in conditioned medium. Immunofluorescent stain for γ-H2AX was used as an index of DNA double strand breaks (DSB). Expression of proteins related to DNA damage repair was assessed by Western blotting.

RESULTS

We found that Shh ligand could protect human HCC HA22T and Sk-Hep1 cells against RT. In HA22T cells, Shh ligand activated the Shh signaling with upregulation of Shh, PTCH-1, and Gli-1 expression. The nuclear translocation of Gli-1 further supports the activation of Gli-1. The radioprotection by Shh ligand was partly blocked by Shh antibody neutralization and was abolished by Gli-1 RNAi, suggesting a critical role of Shh signaling in radiation resistance. Furthermore, we noted that soluble factors secreted into conditioned medium, either constitutively or responding to radiation, by HA22T or Sk-Hep1 cells protected subsequent culturing cells against RT. Immunoprecipitation shows the presence of Shh peptide in conditioned medium. Intriguingly, antibody neutralization of Shh ligand or knockdown of Gli-1 reversed the radioprotective effect of conditioned medium. Furthermore, Shh ligand reduced the RT-induced phosphorylation of checkpoint kinase 1 and impaired the repair of DNA DSB.

CONCLUSIONS

Activation of Shh signaling protects HCC cells against ionizing radiation in an autocrine manner. Impairment of DNA damage repair might involve mechanism of Shh-induced radioresistance. Targeting Shh signaling pathway may be a novel strategy to enhance the radioresponse of human HCC cells.

Early α-fetoprotein response as a predictor for clinical outcome after localized concurrent chemoradiotherapy for advanced hepatocellular carcinoma

BACKGROUNDS

There are limitations in using only radiological criteria to evaluate treatment outcomes in hepatocellular carcinoma (HCC). α-fetoprotein (AFP) is regarded as an indicator of tumour activity in HCC.

AIMS

We present a novel correlation between AFP response and survival outcome in patients treated with localized concurrent chemoradiotherapy (CCRT).

MATERIALS

From 2005 to 2008, 187 locally advanced HCC patients underwent localized CCRT (external beam radiotherapy at 45 Gy over 5 weeks plus a concurrent hepatic arterial infusion of 5-fluorouracil during the first/fifth week), followed by repetitive hepatic arterial infusional chemotherapy (HAIC) with 5-fluorouracil and cisplatin. Among them, 149 with an elevated baseline AFP level (>20 ng/ml) were finally studied. AFP response was defined as >50% decrease from baseline, 1 month after the completion of localized CCRT.

RESULTS

Patients' characteristics were as follows: median age (52 years); Child-Pugh class A/B (n=137/12 respectively); and portal vein thrombosis (n=118). AFP responders (101 patients) had better objective responses than AFP non-responders (48 patients) after CCRT (44.5 vs. 12.5%; P<0.001) and subsequent HAIC (51.5 vs. 16.7%; P<0.001). Both median progression-free survival (PFS, 8.1 vs. 3.9 months; P<0.001) and overall survival (OS, 13.3 vs. 5.9 months; P<0.001) were longer in AFP responders than AFP non-responders. In multivariate analysis, AFP response and objective response were independent factors affecting PFS and OS. Furthermore, AFP non-responders were more likely to have extrahepatic metastasis within 6 months of treatments initiation than AFP responders (59.5 vs. 25.9%; P<0.001).

CONCLUSIONS

Early AFP response may be useful not only in predicting prognosis and treatment response but also in establishing optimized treatment plans for HCC.

Antimetastatic activity of polyphenol-rich extract of Ecklonia cava through the inhibition of the Akt pathway in A549 human lung cancer cells

An ethyl acetate extract (ECE) of a brown alga, Ecklonia cava, was examined for its anti-metastatic effect, using A549 human lung carcinoma cells. ECE treatment significantly suppressed the migration and invasion of A549 cells in a concentration-dependent manner. It also strongly down-regulated the matrix metalloproteinase (MMP)-2 activity of the cancer cells by gelatin zymography assay. For elucidating its mechanism of action in cancer cell metastasis, ECE was further investigated for various cell signalling pathways, including JNK, ERK, p38, and Akt. In this, ECE showed an anti-metastatic effect in a concentration- and time-dependent manner by the mechanism of suppression of Akt and p38, but not JNK and ERK. These results, for the first time, suggest that ECE (a polyphenol-enriched, highly anti-oxidative fraction of brown alga, E. cava) may have therapeutic potential in metastatic lung cancer, based on its strong inhibitory effects on the migration and invasiveness of A549 human lung adenocarcinoma cells.

Influence of stress on extracellular matrix and integrin biology

Dynamic interactions between cells and extracellular matrix (ECM) through integrins influence most cellular functions. Normal cells, but even more, tumor cells are subjected to different forms of stress, including ischemia, radical oxygen species production, starvation, mechanical stress or genotoxic insults due to anti-cancer drugs or irradiation. In these situations, an adaptative cellular response occurs, integrating a complex network of intracellular signaling modules, which, depending on stress intensity, may result to either damage repair followed by complete restitution of cellular functions, or programmed cell death. Because of its implication in oncogenesis and anti-cancer therapy, cellular stress response has been thoroughly investigated. However, most of these studies have been performed in the context of isolated cells without taking into consideration that most cells are part of the tissue within which they interact with ECM through integrin. Few studies have described the influence of stress on cell-to-ECM interaction. However, one can speculate that, in these conditions, cells could functionally interact with protein microenvironment either to create positive interactions to survive (for example by facilitating protective pathways) or negative interaction to die (for example by facilitating detachment). In this review, we summarize the knowledge relative to the influence of different stress modalities on ECM remodeling, integrin expression and/or function modifications, and possible functional consequences, independently from the cellular model as these findings came from a large variety of cells (mesenchymal, endothelial, muscular, epithelial and glandular) and fields of application (cancer, vascular biology and tissue engineering). Most studies support the general notion that non-lethal stress favors ECM stiffness, integrin activation and enhanced survival. This field opens large perspectives not only in tumor biology but also in anti-cancer therapy by targeting one or several steps of the integrin-mediated signaling pathway, including integrin ligation, or activation of integrin-linked enzymes or integrin adaptors.

uPAR/cathepsin B overexpression reverse angiogenesis by rescuing FAK phosphorylation in uPAR/cathepsin B down regulated meningioma

BACKGROUND

Meningiomas are the most commonly occurring intracranial tumors and account for approximately 15-20% of central nervous system tumors. Surgery and radiation therapy is a common treatment for brain tumors, however, patients whose tumors recur after such treatments have limited therapeutic options. Earlier studies have reported important roles of uPA, uPAR and cathepsin B in tumor progression.

METHODOLOGY/PRINCIPAL FINDINGS

In the present study, we examined the therapeutic significance of RNAi-mediated simultaneous down regulation of these proteolytic networks using two bicistronic siRNA constructs, pUC (uPAR/cathepsin B) and pU2 (uPA/uPAR) either alone or in combination with radiation in two different meningioma cell lines. Transfection of meningioma cells with pUC and pU2 significantly reduced angiogenesis as compared to control treatment both in vitro and in vivo nude mice model. This effect is mediated by inhibiting angiogenic molecules (Ang-1, Ang-2 and VEGF). Expression of focal adhesion kinase (FAK) is elevated in malignant meningioma, yet the role of intrinsic FAK activity in promoting tumor progression remains undefined. We found that pUC treatment reduced FAK phosphorylation at Y925 more efficiently compared to pU2 treatment. In immunoprecipitation assay, we found pronounced reduction of FAK (Y925) interaction with Grb2 in meningioma cells transfected with pUC with and without irradiation. Transient over-expression of uPAR and cathepsin B by full length uPAR/cathepsin B (FLpU/C) in pUC transfected meningioma cells promoted vascular phenotype, rescued expression of Ang-1, Ang-2, VEGF, FAK (Y925) and Grb2 both in vitro and in vivo mice model.

CONCLUSION/SIGNIFICANCE

These studies provide the first direct proof that bicistronic siRNA construct for uPAR and cathepsin B (pUC) reduces Y925-FAK activity and this inhibition is rescued by overexpression of both uPAR and cathepsin B which clearly demonstrates that pUC could thus be a potential therapeutic approach as an anti-angiogenic agent in meningioma.

The tumor microenvironment in hepatocellular carcinoma: current status and therapeutic targets

A growing body of literature highlights the cross-talk between tumor cells and the surrounding peri-tumoral stroma as a key modulator of the processes of hepatocarcinogenesis, epithelial mesenchymal transition (EMT), tumor invasion and metastasis. The tumor microenvironment can be broadly classified into cellular and non-cellular components. The major cellular components include hepatic stellate cells, fibroblasts, immune, and endothelial cells. These cell types produce the non-cellular components of the tumor stroma, including extracellular matrix (ECM) proteins, proteolytic enzymes, growth factors and inflammatory cytokines. The non-cellular component of the tumor stroma modulates hepatocellular carcinoma (HCC) biology by effects on cancer signaling pathways in tumor cells and on tumor invasion and metastasis. Global gene expression profiling of HCC has revealed that the tumor microenvironment is an important component in the biologic and prognostic classification of HCC. There are substantial efforts underway to develop novel drugs targeting tumor-stromal interactions. In this review, we discuss the current knowledge about the role of the tumor microenvironment in pathogenesis of HCC, the role of the tumor microenvironment in the classification of HCC and efforts to develop treatments targeting the tumor microenvironment.

Phase II study of concomitant thalidomide during radiotherapy for hepatocellular carcinoma

PURPOSE

Thalidomide has been demonstrated to possess antitumor activity in patients with advanced hepatocellular carcinoma (HCC). The objective of the present study was to determine whether the combined treatment of thalidomide with radiotherapy (RT) is associated with acceptable toxicity and an improved clinical outcome in HCC patients.

METHODS AND MATERIALS

A total of 24 patients were enrolled to receive RT combined with thalidomide. A total dose of 50 Gy was delivered in 2-Gy fractions within 5 weeks. Thalidomide was administered 100 mg twice daily starting 3 days before RT until the development of unacceptable toxicity or disease progression. Blood samples were collected before, during, and after treatment to measure the levels of angiogenic factors and cytokines. The results of patients receiving the combined therapy were compared with those from 18 HCC patients receiving RT only.

RESULTS

No significant difference in the clinical parameters was noted between the two groups, except for the baseline interleukin-6 level, which was greater in the concomitant group (p = .05). The most common toxicities related to thalidomide use were skin rash (54.2%), somnolence (37.5%), and constipation (33.3%). No significant differences were seen in the response rate (55.6% vs. 58.3%, p = .48), median progression-free survival (182 ± 48.9 vs. 148 ± 6.2 days, p = .15), or median overall survival (258 ± 45.6 vs. 241 ± 38.6, p = .16) between those who received concomitant therapy and those who received RT alone. Thalidomide suppressed the serum basic fibroblast growth factor level significantly during RT (p = .03) and, to a lesser extent, the interleukin-6 and tumor necrosis factor-α levels. After adjusting for other potential prognostic factors in the multivariate analysis, only the baseline interleukin-6 level and stem cell-derived factor-1 during RT independently predicted the progression-free survival. A decreased serum stem cell-derived factor-1 level 1 month after RT completion was a significant predictor of the overall survival of HCC patients receiving RT.

CONCLUSIONS

Despite the acceptable toxicity, thalidomide provided no additional benefit for HCC patients undergoing RT.

[Sorafenib and radiotherapy association for hepatocellular carcinoma]

Conformal radiotherapy is a promising therapeutic strategy for hepatocellular carcinoma (HCC), producing local control rates above 90% within the radiation beam. However, survival after radiotherapy remains limited by the high frequency of intra- and extra-hepatic recurrences, which occurs in 40-50 and 20-30% of cases, respectively. Sorafenib (BAY43-9006, Nexavar; Bayer, West Haven, CT) is a small-molecule inhibitor that demonstrated potent activity to target v-raf murine sarcoma oncogene homolog B1 (BRAF) and VEGFR tyrosine kinases. Sorafenib is the only drug that demonstrated effectiveness to increase overall survival in advanced or metastatic hepatocellular carcinoma. The rationale to combine radiotherapy with sorafenib is the following: (1) targeting RAS-RAF-MAPK and VEGFR signaling pathways, which are specifically activated after exposure to radiation, and responsible for radio-resistance phenomenon; (2) enhancing the oxygen effect through normalization of the surviving tumor vasculature; and (3) synchronization of the cell cycle. Sorafenib and radiotherapy represent complementary strategies, as radiotherapy may be useful to prolong the effect of sorafenib through control of the macroscopic disease, when sorafenib may target latent microscopic disease. Sorafenib and radiotherapy associations are thus based on a relevant biological and clinical rationale and are being evaluated in ongoing phase I-II trials.

Targeting inflammatory pathways for tumor radiosensitization

Although radiation therapy (RT) is an integral component of treatment of patients with many types of cancer, inherent and/or acquired resistance to the cytotoxic effects of RT is increasingly recognized as a significant impediment to effective cancer treatment. Inherent resistance is mediated by constitutively activated oncogenic, proliferative and anti-apoptotic proteins/pathways whereas acquired resistance refers to transient induction of proteins/pathways following radiation exposure. To realize the full potential of RT, it is essential to understand the signaling pathways that mediate inducible radiation resistance, a poorly characterized phenomenon, and identify druggable targets for radiosensitization. Ionizing radiation induces a multilayered signaling response in mammalian cells by activating many pro-survival pathways that converge to transiently activate a few important transcription factors (TFs), including nuclear factor kappa B (NF-κB) and signal transducers and activators of transcription (STATs), the central mediators of inflammatory and carcinogenic signaling. Together, these TFs activate a wide spectrum of pro-survival genes regulating inflammation, anti-apoptosis, invasion and angiogenesis pathways, which confer tumor cell radioresistance. Equally, radiation-induced activation of pro-inflammatory cytokine network (including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α) has been shown to mediate symptom burden (pain, fatigue, local inflammation) in cancer patients. Thus, targeting radiation-induced inflammatory pathways may exert a dual effect of accentuating the tumor radioresponse and reducing normal tissue side-effects, thereby increasing the therapeutic window of cancer treatment. We review recent data demonstrating the pivotal role played by inflammatory pathways in cancer progression and modulation of radiation response.

Platelet lysate modulates MMP-2 and MMP-9 expression, matrix deposition and cell-to-matrix adhesion in keratinocytes and fibroblasts

Cell-matrix interactions are an essential element of wound healing, while platelet derivatives are used in clinical settings for the treatment of chronic wounds. We used a platelet lysate (PL), which had been previously shown to accelerate in vitro the wounding of HaCaT keratinocytes and fibroblasts (J Cell Mol Med, 13, 2009, 2030; Br J Dermatol, 159, 2008, 537), to study the modulation of MMP-2 and MMP-9 collagenase expression, collagen type I and III production and syndecan-4 expression and rearrangement in these cells. Zymography and Western blot analyses showed that exposure to 20% (v/v) PL for 24 h induced an apparently ERK1/2- and p38-dependent, NF-kappaB-independent, translational upregulation of MMP-9 in HaCaT, while HaCaT MMP-2 and fibroblast collagenases were almost unaffected. The use of in-cell ELISA showed that PL induced an increase in the collagen III production of fibroblasts. In-cell ELISA and immunofluorescence microscopy revealed an increase in the expression of syndecan-4 and its rearrangement to form focal adhesions in both cell types after PL exposure. Taken together, data indicate that PL promotes keratinocyte epithelialization and regulates fibroblast matrix deposition, thus providing a molecular basis for the ability of this platelet derivative to heal severe and problematic wounds without leading to heavy scarring and keloid formation.

Suppression of uPAR retards radiation-induced invasion and migration mediated by integrin β1/FAK signaling in medulloblastoma

BACKGROUND

Despite effective radiotherapy for the initial stages of cancer, several studies have reported the recurrence of various cancers, including medulloblastoma. Here, we attempt to capitalize on the radiation-induced aggressive behavior of medulloblastoma cells by comparing the extracellular protease activity and the expression pattern of molecules, known to be involved in cell adhesion, migration and invasion, between non-irradiated and irradiated cells.

METHODOLOGY/PRINCIPAL FINDINGS

We identified an increase in invasion and migration of irradiated compared to non-irradiated medulloblastoma cells. RT-PCR analysis confirmed increased expression of uPA, uPAR, focal adhesion kinase (FAK), N-Cadherin and integrin subunits (e.g., α3, α5 and β1) in irradiated cells. Furthermore, we noticed a ∼2-fold increase in tyrosine phosphorylation of FAK in irradiated cells. Immunoprecipitation studies confirmed increased interaction of integrin β1 and FAK in irradiated cells. In addition, our results show that overexpression of uPAR in cancer cells can mimic radiation-induced activation of FAK signaling. Moreover, by inhibiting FAK phosphorylation, we were able to reduce the radiation-induced invasiveness of the cancer cells. In this vein, we studied the effect of siRNA-mediated knockdown of uPAR on cell migration and adhesion in irradiated and non-irradiated medulloblastoma cells. Downregulation of uPAR reduced the radiation-induced adhesion, migration and invasion of the irradiated cells, primarily by inhibiting phosphorylation of FAK, Paxillin and Rac-1/Cdc42. As observed from the immunoprecipitation studies, uPAR knockdown reduced interaction among the focal adhesion molecules, such as FAK, Paxillin and p130Cas, which are known to play key roles in cancer metastasis. Pretreatment with uPAR shRNA expressing construct reduced uPAR and phospho FAK expression levels in pre-established medulloblastoma in nude mice.

CONCLUSION/SIGNIFICANCE

Taken together, our results show that radiation enhances uPAR-mediated FAK signaling and by targeting uPAR we can inhibit radiation-activated cell adhesion and migration both in vitro and in vivo.

Nonsurgical options for hepatocellular carcinoma: evolving role of external beam radiotherapy

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and thus poses a global concern. Its incidence is expected to increase in North America secondary to the increasing incidence of patients who develop hepatitis C. Patients who ultimately develop cirrhosis have an increased risk of developing hepatocellular carcinoma.

METHODS

The authors focus on nonsurgical therapies for this disease with an exploration of how external beam radiotherapy can be used alone or with other modalities. The development of partial liver strategies secondary to an explosion in radiation treatment planning and delivery advances is reviewed. Integration of advanced technology has evolved from three-dimensional conformal treatment to intensity-modulated radiation therapy and image-guided radiation therapy, along with stereotactic body radiation therapy, tomotherapy, and proton beam therapy.

RESULTS

Current data show a promising future for treatment strategies incorporating radiation with high rates of infield tumor control and low rates of radiation-induced liver disease. Radiation can be delivered in conjunction with transarterial catheter embolization for advanced-stage patients. External beam radiotherapy also has a role in the setting of patients with macrovascular tumor thrombus.

CONCLUSIONS

Future directions include how to best synergize the effects of radiation strategies with novel agents, given the hypervascularity of HCC. Downstaging of larger lesions with these therapies to resectable or transplantable disease may lead to better outcomes for patients deemed inoperable at diagnosis, and definitive radiotherapy may offer cure to patients with smaller lesions.

Anti-invasive effect of a rare mushroom, Ganoderma colossum , on human hepatoma cells

Ganoderma colossum is a rare species of the Ganodermataceae family with biological activity but has not been widely used to date. Because of its rareness and hard availability, the literature regarding the bioactivity of G. colossum is very limited and the bioactive components in G. colossum have never been explored. In the present study, an ethanol extract was prepared from the fruiting body of a G. colossum strain (EEGC) and then fractionated by reverese-phase high-performance liquid chromatography (HPLC). The inhibitory effects and molecular mechanisms of the EEGC on the phorbol-12-myristate-13-acetate (PMA)-induced invasion of HepG2 cells were investigated. The fractions of the EEGC cannot be totally identified, but the lucidenic acids were considered as the major component. When HepG2 cells were treated with the EEGC, the PMA-induced invasion was reduced in a dose-dependent manner and the PMA-induced matrix metalloproteinase (MMP)-9 was also suppressed at the transcriptional level. The EEGC also showed an inhibitory effect on the PMA-induced phosphorylation of extracellular signal-regulated kinase (ERK1/2) and protein kinase B (Akt) in cytosol, as well as the activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) levels in the nucleus of HepG2 cells. This study provides the first evidence demonstrating that the EEGC is an effective inhibitior on the PMA-induced invasion of hepatoma cell. The EEGC could be further tested by an in vivo model to verify whether it is effective for the prevention of hepatoma invasion or metastasis.

Activation of PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway is required for the apoptosis-evasion in human salivary adenoid cystic carcinoma: its inhibition by quercetin

Quercetin, one of the most common natural flavonoids, has been reported to possess significant anti-tumor activities both in vitro and in vivo. The present study was to investigate the effects of quercetin on growth and apoptosis in human salivary adenoid cystic carcinoma (ACC). The result from MTT assay showed that quercetin decreased cell viability of both low metastatic cell line ACC-2 and high metastatic cell line ACC-M in a concentration- and time-dependent manner. Moreover, treatment with quercetin resulted in significantly increased apoptosis in ACC cells. Our data also revealed that the apoptosis induced by quercetin treatment was through a mitochondria-dependent pathway which showed close correlation with the down-regulation of the PI3K/Akt/IKK-alpha/NF-kappaB pathway. Most importantly, quercetin significantly prevented in vivo growth of ACC xenografts in nude mice, accompanied by induction of tumor cell apoptosis, suppression of NF-kappaB nuclear translocation, as well as down-regulation of Akt and IKK-alpha activation. In addition, we explored the clinical significance of the PI3K/Akt/IKK-alpha/NF-kappaB signaling axis in ACC by immunohistochemical analysis of tissue specimens followed by the clustering analyses. We determined that the PI3K/Akt/IKK-alpha/NF-kappaB pathway is ubiquitously activated in ACC and plays an essential role in the evasion of apoptosis. Taken together, the results from our study implicated that quercetin would be a promising chemotherapeutic agent against ACC through its function of down-regulating the PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway.

The effect of focal adhesion kinase gene silencing on 5-fluorouracil chemosensitivity involves an Akt/NF-kappaB signaling pathway in colorectal carcinomas

Multicellular resistance (MCR) is produced because multicellular spheroids (MCSs) are formed with a broad cell-cell connection when cultured in three-dimensions, which limits the clinical treatment efficacy in solid tumors. Focal adhesion kinase (FAK) plays an important role in apoptosis, survival and cell adhesion between cells and their extracellular matrix. In this study, we investigated the expressions of FAK, Akt and NF-kappaB in human colorectal cancer (CRC), and the effects of FAK gene silencing on MCSs formation and 5-fluorouracil (5-FU) chemosensitivity in colon carcinoma MCSs culture cells. In CRC samples, FAK, Akt and NF-kappaB were overexpressed. The positive expression of FAK correlated notably with lymph node metastasis and cellular differentiation. Positive expressions of Akt and NF-kappaB were significantly related to cellular differentiation and lymph node metastasis, respectively. Furthermore, positive expression of FAK correlated with that of Akt and NF-kappaB. The expression of FAK was inhibited significantly by a small hairpin RNA targeting FAK. Knockdown of FAK reversed the formation and aggregation of MCSs, significantly decreased the 50% inhibitory concentration of 5-FU, and markedly increased MCS culture cells apoptosis. These effects were associated with reduced levels of Akt and NF-kappaB. These results indicate that suppressing FAK expression potentiated 5-FU-induced cytotoxicity and contributed to its chemosensitizing effect by suppressing Akt/NF-kappaB signaling in colon carcinoma MCS culture cells. These data also imply that FAK mediates MCR of CRC through the survival signaling pathway FAK/Akt/NF-kappaB.

Bcl-XL and STAT3 mediate malignant actions of gamma-irradiation in lung cancer cells

Previous reports suggest that, in addition to its therapeutic effects, ionizing radiation (IR) increases the invasiveness of surviving cancer cells. Here, we demonstrate that this activity of IR in lung cancer cells is mediated by a signaling pathway involving p38 kinase, phosphoinositide 3-kinase, Akt, and matrix metalloproteinase (MMP-2). The invasion-promoting doses of IR also increased and reduced the levels of vimentin and E-cadherin, respectively, both of which are markers for the epithelial-mesenchymal transition (EMT). Interestingly, all of these malignant actions of IR were mimicked by the overexpression of Bcl-X(L), a pro-survival member of the Bcl-2 family, in lung cancer cells. Moreover, both RNA and protein levels of Bcl-X(L) were elevated upon irradiation of the cells, and the prevention of this event using small-interfering RNAs of Bcl-X(L) reduced the ability of IR to promote invasion signals and EMT-associated events. This suggests that Bcl-X(L) functions as a signaling mediator of the malignant effects of IR. It was also demonstrated that IR enhances signal transducer and activator of transcription 3 (STAT3) phosphorylation, and the reduction of STAT3 levels via RNA interference prevented IR-induced Bcl-X(L) accumulation, and thus all the tested Bcl-X(L)-dependent events. Overall, the data suggest that IR induces Bcl-X(L) accumulation via STAT3, which then promotes cancer cell invasion and EMT-associated markers. Our findings demonstrate a novel function of Bcl-X(L) in cancer, and also advance our understanding of the malignant actions of IR significantly.

Innovative immunohistochemistry identifies MMP-9 expressing macrophages at the invasive front of murine HCC

AIM

To investigate the proteolytic contribution of tumor-associated macrophages (TAM) in tumor invasion, we analyzed whether TAM at the invasive front of small HCC in Abcb4(-/-)-mice show an enhanced expression of MMP-9.

METHODS

Liver cryosections of the hepatocellular carcinoma (HCC) invasive front from 12 mo old Abcb4(-/-)-mice were stained for collagen type I and MMP-9 using Alexa488 and Alexa568 labeled secondary antibodies. Afterwards, the Alexa568 dye was bleached and the macrophage marker F4/80 was visualized using Alexa568 labeled secondary antibodies. Finally, photographs of the invasive tumor front were digitally overlaid and analyzed.

RESULTS

After complete bleaching of the primary dye, specific fluorescence staining of a third antigen, here F4/80, was successfully performed on the same histological section. With this method, we were able to identify conglomerates of matrix metalloproteinase (MMP-9) expressing macrophages within the tumor capsule of HCC.

CONCLUSION

MMP-9 expressing macrophages are involved in matrix remodelling at the invasive tumor front of HCC. The described staining protocol provides a simple yet powerful extension of conventional immuno-histochemistry, facilitating visualization of at least three different antigens plus nuclei in one single histological section.

Effects of irradiation on tumor cell survival, invasion and angiogenesis

Ionizing irradiation is a widely applied therapeutic method for the majority of solid malignant neoplasms, including brain tumors where, depending on localization, this might often be the only feasible primary intervention.Without doubt, it has been proved to be a fundamental tool available in the battlefield against cancer, offering a clear survival benefit in most cases. However, numerous studies have associated tumor irradiation with enhanced aggressive phenotype of the remaining cancer cells. A cell population manages to survive after the exposure, either because it receives sublethal doses and/or because it successfully utilizes the repair mechanisms. The biology of irradiated cells is altered leading to up-regulation of genes that favor cell survival, invasion and angiogenesis. In addition, hypoxia within the tumor mass limits the cytotoxicity of irradiation, whereas irradiation itself may worsen hypoxic conditions, which also contribute to the generation of resistant cells. Activation of cell surface receptors, such as the epidermal growth factor receptor, utilization of signaling pathways, and over-expression of cytokines, proteases and growth factors, for example the matrix metalloproteinases and vascular endothelial growth factor, protect tumor and non-tumor cells from apoptosis, increase their ability to invade to adjacent or distant areas, and trigger angiogenesis. This review will try to unfold the various molecular events and interactions that control tumor cell survival, invasion and angiogenesis and which are elicited or influenced by irradiation of the tumor mass, and to emphasize the importance of combining irradiation therapy with molecular targeting.

Effect of black raspberry extract in inhibiting NFkappa B dependent radioprotection in human breast cancer cells

Black raspberry extracts (RSE) have been shown to inhibit cancer cell growth and stimulate apoptosis. Also, studies have demonstrated that RSE inhibits transcriptional regulators including NFkappa B. Accordingly, we investigated the effect of RSE in inhibiting radiation (IR) induced NFkappa B mediated radioprotection in breast adenocarcinoma cells. MCF-7 cells were exposed to IR (2Gy), treated with RSE (0.5, 1.0, 2.0 micro g/ml) or treated with RSE (1.0 micro g/ml) followed by IR exposure, and harvested after 1, 3, 6, 24, 48, and 72 h. NFkappa B DNA-binding activity was measured by EMSA and phosphorylated Ikappa Balpha by immunoblotting. Expression of IAP1, IAP2, XIAP and survivin were measured by QPCR and immunoblotting. Cell survival was measured using MTT assay and cell death using Caspase-3/7 activity. Effect of RSE on IR induced MnSOD, TNFalpha, IL-1alpha and MnSOD activity was also determined. RSE inhibited NFkappa B activity in a dose-dependent manner. Also, RSE inhibited IR-induced sustained activation of NFkappa B, and NFkappa B regulated IAP1, IAP2, XIAP, and survivin. In addition, RSE inhibited IR-induced TNFalpha, IL-1alpha, and MnSOD levels and MnSOD activity. RSE suppressed cell survival and enhanced cell death. These results suggest that RSE may act as a potent radiosensitizer by overcoming the effects of NFkappa B mediated radioprotection in human breast cancer cells.

Maintenance of Sorafenib following combined therapy of three-dimensional conformal radiation therapy/intensity-modulated radiation therapy and transcatheter arterial chemoembolization in patients with locally advanced hepatocellular carcinoma: a phase I/II study

BACKGROUND

Three-dimensional conformal radiation therapy (3DCRT)/intensity-modulated radiation therapy (IMRT) combined with or without transcatheter arterial chemoembolization (TACE) for locally advanced hepatocellular carcinoma (HCC) has shown favorable outcomes in local control and survival of locally advanced HCC. However, intra-hepatic spreading and metastasis are still the predominant treatment failure patterns. Sorafenib is a multikinase inhibitor with effects against tumor proliferation and angiogenesis. Maintenance Sorafenib would probably prevent or delay the intrahepatic and extrahepatic spread of HCC after radiotherapy, which provides the rationale for the combination of these treatment modalities.

METHODS AND DESIGN

Patients with solitary lesion (bigger than 5 cm in diameter) histologically or cytologically confirmed HCC receive TACE (1-3 cycles) plus 3DCRT/IMRT 4-6 weeks later. Maintenance Sorafenib will be administered only for the patients with non-progression disease 4 to 6 weeks after the completion of radiotherapy. The dose will be 400 mg, p.o., twice a day. Sorafenib will be continuously given for 12 months unless intolerable toxicities and/or tumor progression. If no more than 3 patients discontinue Sorafenib treatment who experience dose-limiting toxicity after necessary dose modification and delay and/or radiation-induced liver disease in the first 15 enrolled patients, the study will recruit second fifteen patients for further evaluating safety and efficacy of treatment. Hypothesis of the current study is that Sorafenib as a maintenance therapy after combined therapy of 3DCRT/IMRT and TACE is safe and superior to radiotherapy combined with TACE alone in terms of time to progression (TTP), progression-free survival (PFS) and overall survival (OS) in comparison to historical data.

DISCUSSION

A recent meta-analysis showed TACE in combination with radiotherapy, improved the survival and the tumor response of patients, and was thus more therapeutically beneficial. In this study, local therapy for HCC is the combination of TACE and radiotherapy. Radiation exposure as a kind of stress might induce the compensatory activations of multiple intracellular signaling pathway mediators, such as PI3K, MAPK, JNK and NF-kB. Vascular endothelial growth factor (VEGF) was identified as one factor that was increased in a time- and dose-dependent manner after sublethal irradiation of HCC cells in vitro, translating to enhanced intratumor angiogenesis in vivo. Therefore, Sorafenib-mediated blockade of the Raf/MAPK and VEGFR pathways might enhance the efficacy of radiation, when Sorafenib is followed sequentially as a maintenance modality. (ClinicalTrials.gov number, NCT00999843.).

Identification of proteins indicating radiation-induced hepatic toxicity in cirrhotic rats

Radiation therapy (RT) has been emerging as one of the palliative treatments for locally advanced hepatocellular carcinoma (HCC). However, hepatic toxicity is a major obstacle in radiotherapy for HCC. The purpose of this study is to identify proteins indicating radiation-induced hepatic toxicity in cirrhotic rats, which can be used as possible biomarkers. Liver cirrhosis was induced in Wistar rats with thioacetamide (TAA) 0.3 g/L in drinking water for 9 weeks. The development of liver cirrhosis was observed histologically. Radiation hepatic injury was induced by treating 1/3 of the liver with 10 Gy single dose radiation. To find out commonly expressed proteins, liver tissue and serum were analyzed using two-dimensional electrophoresis and quadrupole time of flight mass spectrometry. Identified proteins were validated using western blotting. Histological examination showed that the degree of hepatic fibrosis increased by radiation in liver cirrhosis. It was associated with a decrease in the proliferation of cell nuclear antigen and an increase of apoptosis. The proteomic analysis of liver tissue and serum identified 60 proteins which showed significant change in expression between the TAA-alone and TAA-plus-radiation groups. Among these, an increase of heparanase precursor and decrease of hepatocyte growth factor were shown commonly in liver tissue and serum following radiation. Hepatic fibrosis increased following radiation in cirrhotic rats. These proteins might be useful in detecting and monitoring radiation-induced hepatic injury.

Suppression of PMA-induced tumor cell invasion and metastasis by aqueous extract isolated from Prunella vulgaris via the inhibition of NF-kappaB-dependent MMP-9 expression

Matrix metalloproteinase-9 (MMP-9) plays an important role in the invasion and metastasis of cancer cells. In this study, we examined the inhibitory effects of tumor cell migration and invasion by aqueous extract isolated from Prunella vulgaris (PVAE) using in vitro and in vivo assays. PVAE reduced PMA-induced activation of MMP-9 and further inhibited cell invasion and migration. PVAE suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of NF-kappaB activation without changing the tissue inhibitor of metalloproteinase level. PVAE inhibited PMA-induced NF-kappaB nuclear translocation, which is upstream of PMA-induced MMP-9 expression and invasion. Furthermore, pretreatment with NF-kappaB activation inhibitor inhibited the PMA-induced MMP-9 expression and activity. PVAE repressed the PMA-induced phosphorylation of ERK1/2, which is upstream signaling molecules in MMP-9 expression. We confirmed that the inhibitory effect of PVAE on lung metastasis and tumor cell growth using B16-F10 melanoma cells or B16-F1 melanoma cells in C57BL/6 mice. The oral administrations of PVAE reduced the lung metastasis and tumor cell growth by B16-F10 or B16-F1 melanoma cells. These results suggested that the anti-metastatic effect of PVAE is mediated through the suppression of MMP-9 expression by the inhibition of NF-kappaB via ERK1/2 signaling pathway as well as MMP-9 activity.

Challenge and hope in radiotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most critical global health issues. With frequent association of viral liver disease, HCC is highly complex, harboring both cancer and chronic liver disease. The tumor stage and underlying liver function are both major determinants of the treatment selection as well as prognosis in HCC patients, thus allowing no more than a 20% chance for potentially curative therapies. Radiotherapy technology has been evolved remarkably during the past decade, and radiation can be precisely delivered, thereby permitting higher doses to the tumour and reduced doses to surrounding normal tissues. There has been increasing interest in the merits of radiotherapy in HCC over the past few years, as indicated by a Pub Med search. Radiotherapy has been used as the definitive therapy with curative intent in early stage tumours. It has been used also in combination with TACE for intermediate stage tumours. In locally advanced tumours, radiotherapy has been combined with systemic agents. Despite its efficacy, radiotherapy has not yet been incorporated into the standard management guidelines of HCC. The lack of high evidence level data, especially randomized controlled trials, has posed an obstacle in including radiotherapy into the routine treatment schema of HCC. Therefore, well-designed prospective studies are strongly recommended using developing technology for radiotherapy alone or combination therapies. Also, many issues such as the optimal dose-fractionation, intra- or extrahepatic metastasis after radiotherapy, and radiation-induced hepatic dysfunction remain to be solved. In this review, current status of radiotherapy for HCC will be discussed with regard to technical consideration and combination strategy. The limitation and future perspectives will also be discussed.

gamma-Irradiation induces P2X(7) receptor-dependent ATP release from B16 melanoma cells

BACKGROUND

Ionizing irradiation causes not only growth arrest and cell death, but also release of growth factors or signal transmitters, which promote cancer malignancy. Extracellular ATP controls cancer growth through activation of purinoceptors. However, there is no report of radiation-induced ATP release from cancer cells. Here, we examined gamma-irradiation-induced ATP release and its mechanism in B16 melanoma.

METHODS

Extracellular ATP was measured by luciferin-luciferase assay. To investigate mechanism of radiation-induced ATP release, we pharmacologically inhibited the ATP release and established stable P2X(7) receptor-knockdown B16 melanoma cells using two short hairpin RNAs targeting P2X(7) receptor.

RESULTS

Cells were exposed to 0.5-8 Gy of gamma-rays. Extracellular ATP was increased, peaking at 5 min after 0.5 Gy irradiation. A selective P2X(7) receptor channel antagonist, but not anion transporter inhibitors, blocked the release of ATP. Further, radiation-induced ATP release was significantly decreased in P2X(7) receptor-knockdown cells. Our results indicate that gamma-irradiation evokes ATP release from melanoma cells, and P2X(7) receptor channel plays a significant role in mediating the ATP release.

GENERAL SIGNIFICANCE

We suggest that extracellular ATP could be a novel intercellular signaling molecule released from cancer cells when cells are exposed to ionizing radiation.

Carbon-ion beam irradiation effectively suppresses migration and invasion of human non-small-cell lung cancer cells

PURPOSE

Control of cancer metastasis is one of the most important issues in cancer treatment. We previously demonstrated that carbon particle irradiation suppresses the metastatic potential of cancer cells, and many studies have reported that photon irradiation promotes it. The purpose of this study was to investigate the effect of carbon beam on non-small-cell lung cancer (NSCLC) cell aggressiveness and gene expression.

METHODS AND MATERIALS

A549 (lung adenocarcinoma) and EBC-1 (lung squamous cell carcinoma) cells were treated with 290 MeV/nucleon carbon ion beam at the Heavy Ion Medical Accelerator in Chiba or with 4-MV X-ray at Osaka University. We tested proliferative, migratory, and invasive activities by cell proliferation assay, Boyden chamber assay, and Matrigel chemoinvasion assay, respectively. cDNA microarray and reverse transcription polymerase chain reaction were also performed to assess mRNA expression alteration.

RESULTS

X-irradiation increased cell proliferation of A549 cells at 0.5 Gy, whereas high-dose X-ray reduced migration and invasion of A549 cells. By contrast, carbon beam irradiation did not enhance proliferation, and it reduced the migration and invasion capabilities of both A549 and EBC-1 cells more effectively than did X-irradiation. Carbon beam irradiation induced alteration of various gene expression profiles differently from X-ray irradiation. mRNA expression of ANLN, a homologue of anillin, was suppressed to 60% levels of basal expression in carbon beam-irradiated A549 cells after 12 h.

CONCLUSION

Carbon beam effectively suppresses the metastatic potential of A549 and EBC-1 cells. Carbon beam also has different effects on gene expressions, and downregulation of ANLN was induced only by carbon beam irradiation.

Osteopontin increases migration and MMP-9 up-regulation via alphavbeta3 integrin, FAK, ERK, and NF-kappaB-dependent pathway in human chondrosarcoma cells

Tumor malignancy is associated with several features such as proliferation ability and frequency of metastasis. Osteopontin (OPN), which abundantly expressed in bone matrix, is involved in cell adhesion, migration, invasion and proliferation via interaction with its receptor, that is, alphavbeta3 integrin. However, the effect of OPN on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that OPN increased the migration and expression of matrix metalloproteinase (MMP)-9 in human chondrosarcoma cells (JJ012 cells). RGD peptide, alphavbeta3 monoclonal antibody and MAPK kinase (MEK) inhibitors (PD98059 and U0126) but not RAD peptide inhibited the OPN-induced increase of the migration and MMP-9 up-regulation of chondrosarcoma cells. OPN stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK and extracellular signal-regulated kinase (ERK). In addition, treatment of JJ012 cells with NF-kappaB inhibitor (PDTC) or IkappaB protease inhibitor (TPCK) inhibited OPN-induced cell migration and MMP-9 up-regulation. Stimulation of JJ012 cells with OPN also induced IkappaB kinase alpha/beta (IKK alpha/beta) phosphorylation, IkappaBalpha phosphorylation, p65 Ser(536) phosphorylation, and kappaB-luciferase activity. The OPN-mediated increases in MMP-9 and kappaB-luciferase activities were inhibited by RGD peptide, PD98059 or FAK and ERK2 mutant. Taken together, our results indicated that OPN enhances the migration of chondrosarcoma cells by increasing MMP-9 expression through the alphavbeta3 integrin, FAK, MEK, ERK and NF-kappaB signal transduction pathway.

Distinction of hepatocellular adenoma from hepatocellular carcinoma with and without cirrhosis using E-cadherin and matrix metalloproteinase immunohistochemistry

We studied the tumor cell expression patterns of E-cadherin and matrix metalloproteinase-1, -2, -7, and -9 in a tissue microarray composed of 20 normal livers, 10 hepatocellular adenomas, 43 hepatocellular carcinomas with cirrhosis and 33 hepatocellular carcinomas without cirrhosis. Hepatocellular adenoma was characterized by the complete absence of matrix metalloproteinase-7 expression; hepatocellular carcinoma with cirrhosis was characterized by a significantly low expression of E-cadherin; and hepatocellular carcinoma without cirrhosis was characterized by low matrix metalloproteinase-9 expression. The staining intensity score of E-cadherin=3, matrix a metalloproteinase-7<1, and matrix metalloproteinase-9>or=2 can be used as the diagnostic criteria for hepatocellular adenoma and for distinguishing hepatocellular adenoma from normal, hepatocellular carcinoma with cirrhosis, and hepatocellular carcinoma without cirrhosis. E-cadherin<2 and matrix metalloproteinase-9<2 can be used for distinguishing both hepatocellular carcinoma with cirrhosis and hepatocellular carcinoma without cirrhosis from normal. Although statistically not significant, hepatocellular carcinoma without cirrhosis showed a higher E-cadherin expression and a lower matrix metalloproteinase-9 expression than hepatocellular carcinoma with cirrhosis, which could be partially responsible for the less aggressive behavior found in hepatocellular carcinoma without cirrhosis when compared with hepatocellular carcinoma with cirrhosis. These results, if confirmed in a further study of small biopsy specimens and of histologically ambiguous cases, could lead to the application of these markers in the diagnosis and differential diagnosis of hepatocellular neoplasms in our surgical pathology practice.

Silencing of heat shock protein 70 expression enhances radiotherapy efficacy and inhibits cell invasion in endometrial cancer cell line

AIM

To investigate the role of heat shock proteins 70 (HSP70) in radiosensitivity and invasiveness of endometrial cancer in vitro.

METHODS

HSP70 expression was silenced in relatively radioresistant, well-differentiated human endometrial cancer cell line ISK, using small interference RNA method, or by HSP70 overexpression after transfecting a HSP70-expressing vector. The effect of HSP70 on ISK cell line response to irradiation was evaluated. The surviving fraction was measured using colony-formation assay. Apoptosis was detected by flow cytometry and HSP70 expression was determined by quantitative real-time polymerase chain reaction, western-blot, and/or immunocytochemistry. Cell invasiveness was measured using transwell invasion assay.

RESULTS

HSP70 silencing caused a significant increase in irradiation-induced cell killing in comparison with control cells, with an enhancement factor of 1.27, and in the percentage of apoptotic cells (14.22% vs 6.74%, P = 0.021). After 4 Gy irradiation, mean +/- standard deviation survival fraction in ISK cells was reduced to 0.32 +/- 0.04 in comparison with control values but in ISK/siRNA-HSP70 cells the survival fraction was higher and amounted to 0.51 +/- 0.08 (P = 0.026). Silencing HSP70 significantly inhibited cell invasion before and after irradiation (106 +/- 19 vs 219 +/- 18 and 119 +/- 16 vs 256 +/- 31, P = 0.007). On the contrary, ectopic overexpression of HSP70 attenuated irradiation-induced apoptosis (7.15% vs 4.08%, P = 0.043) and induced more ISK/HSP70 cells invaded through the filters than mock-infected cells before and after irradiation (274 +/- 21 vs 194 +/- 16 before irradiation, and 298 +/- 24 vs 227 +/- 19 after irradiation, respectively, P = 0.032).

CONCLUSION

Disruption of HSP70-induced cytoprotection during irradiation enhances therapeutic effect of irradiation, which makes HSP70 a promising target in the research of endometrial cancer.

Inhibitory effects of ganoderma lucidum on tumorigenesis and metastasis of human hepatoma cells in cells and animal models

Metastasis is considered to be the major cause of death in patients with cancers, and hepatocellular carcinoma (HCC) is a highly metastatic cancer. Ganoderma lucidum , a well-known mushroom with various biological effects, is a functional food known to contain lucidenic acid. The objectives of this study were to investigate the anti-invasion effect of a lucidenic acid-rich G. lucidum extract (GLE) on human hepatoma HepG2 cells as well as the antiproliferative and antimetastatic effects of GLE in human hepatoma cells implanted into ICR-nu/nu mice. Phorbol-12-myristate-13-acetate (PMA)-induced invasion and matrix metalloproteinase (MMP)-9 expression levels of HepG2 cells were reduced by GLE treatment in a dose-dependent manner. The inhibitory effects of GLE on MMP-9 expression proceeded by inhibiting the phosphorylation of extracellular signal-regulated kinase (ERK1/2) and protein kinase B in the cytosol as well as reducing activator protein-1 and nuclear factor-kappa B levels in the nucleus of HepG2 cells. In a human tumor xenograft model, a dose-response inhibition was observed in the average size, volume, and weight of tumors upon oral administration of GLE. The number of metastatic tumor-bearing mice, the number of affected organs, and the number of tumor foci as well as the MMP-2 and -9 activities in serum of mice were also significantly suppressed by oral administration of GLE. These results suggest that the lucidenic acid-rich GLE could serve as a chemopreventive agent for the tumorigenesis and metastasis of highly invasive hepatoma cells.

Regulation of expression of matrix metalloproteinase-9 by JNK in Raw 264.7 cells: presence of inhibitory factor(s) suppressing MMP-9 induction in serum and conditioned media

Matrix metalloproteinase-9 (MMP-9) secreted from macrophages plays an important role in tissue destruction and inflammation through degradation of matrix proteins and proteolytic activation of cytokines/chemokines. Whereas the MEK-ERK and PI3K- Akt pathways up-regulate MMP-9 expression, regulation of MMP-9 by JNK remains controversial. Presently, we aimed to determine the role of JNK in MMP-9 regulation in Raw 264.7 cells. Inhibition of JNK by the JNK inhibitor SP600125 induced MMP-9 in the absence of serum and suppressed the expression of TNF-alpha, IL-6 and cyclooxygenase-2 in LPS-treated Raw 264.7 cells. In a knockdown experiment with small interfering RNA, suppression of JNK1 induced MMP-9 expression. Interestingly, mouse serum suppressed SP600125- mediated MMP-9 induction, similar to IFN-gamma. However, the inhibitory activity of mouse serum was not affected by pyridone 6, which inhibits Janus kinase downstream to IFN-gamma. In addition to mouse serum, conditioned media of Raw 264.7 cells contained the inhibitory factor(s) larger than 10 kDa, which suppressed SP600125- or LPS-induced MMP-9 expression. Taken together, these data suggest that JNK1 suppresses MMP-9 expression in the absence of serum. In addition, the inhibitory factor(s) present in serum or secreted from macrophages may negatively control MMP-9 expression.

Simvastatin inhibits induction of matrix metalloproteinase-9 in rat alveolar macrophages exposed to cigarette smoke extract

Matrix metalloproteinase-9 (MMP-9) may play an important role in emphysematous change in chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality and morbidity worldwide. We previously reported that simvastatin, an inhibitor of HMG-CoA reductase, attenuates emphysematous change and MMP-9 induction in the lungs of rats exposed to cigarette smoke. However, it remained uncertain how cigarette smoke induced MMP-9 and how simvastatin inhibited cigarette smoke-induced MMP-9 expression in alveolar macrophages (AMs), a major source of MMP-9 in the lungs of COPD patients. Presently, we examined the related signaling for MMP-9 induction and the inhibitory mechanism of simvastatin on MMP-9 induction in AMs exposed to cigarette smoke extract (CSE). In isolated rat AMs, CSE induced MMP-9 expression and phosphorylation of ERK and Akt. A chemical inhibitor of MEK1/2 or PI3K reduced phosphorylation of ERK or Akt, respectively, and also inhibited CSE-mediated MMP-9 induction. Simvastatin reduced CSE-mediated MMP-9 induction, and simvastatin-mediated inhibition was reversed by farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP). Similar to simvastatin, inhibition of FPP transferase or GGPP transferase suppressed CSE-mediated MMP-9 induction. Simvastatin attenuated CSE-mediated activation of RAS and phosphorylation of ERK, Akt, p65, IkappaB, and nuclear AP-1 or NF-kappaB activity. Taken together, these results suggest that simvastatin may inhibit CSE-mediated MMP-9 induction, primarily by blocking prenylation of RAS in the signaling pathways, in which Raf-MEK-ERK, PI3K/Akt, AP-1, and IkappaB-NF-kappaB are involved.

The novel Akt inhibitor Palomid 529 (P529) enhances the effect of radiotherapy in prostate cancer

Radiotherapy (RT) is a common treatment for localised prostate cancer, but can cause important side effects. The therapeutic efficacy of RT can be enhanced by pharmacological compounds that target specific pathways involved in cell survival. This would elicit a similar therapeutic response using lower doses of RT and, in turn, reducing side effects. This study describes the antitumour activity of the novel Akt inhibitor 8-(1-Hydroxy-ethyl)-2-methoxy-3-(4-methoxy-benzyloxy)-benzo[c]chromen-6-one (Palomid 529 or P529) as well as its ability to decrease radiation-activated phospho-Akt (p-Akt) signalling in a prostate cancer model. P529 showed a potent antiproliferative activity in the NCI-60 cell lines panel, with growth inhibitory 50 (GI50) <35 microM. In addition, P529 significantly enhanced the antiproliferative effect of radiation in prostate cancer cells (PC-3). Analysis of signalling pathways targeted by P529 exhibited a decrease in p-Akt, VEGF, MMP-2, MMP-9, and Id-1 levels after radiation treatment. Moreover, the Bcl-2/Bax ratio was also reduced. Treatment of PC-3 tumour-bearing mice with 20 mg kg(-1) P529 or 6 Gy radiation dose decreased tumour size by 42.9 and 53%, respectively. Combination of both treatments resulted in 77.4% tumour shrinkage. Decreased tumour growth was due to reduced proliferation and increased apoptosis (as assessed by PCNA and caspase-3 immunostaining). Our results show the antitumour efficacy of P529 alone, and as a radiosensitiser, and suggest that this compound could be used in the future to treat human prostate cancer.

Involvement of PI3K/PTEN/AKT/mTOR pathway in invasion and metastasis in hepatocellular carcinoma: Association with MMP-9

AIM

To investigate the status of Phosphatidylinositol 3-kinase (PI3K)/PTEN/AKT/mammalian target of rapamycin (mTOR) pathway and its correlation with clinicopathological features and matrix metalloproteinase-2, -9 (MMP-2, 9) in human hepatocellular carcinoma (HCC).

METHODS

PTEN, Phosphorylated AKT (p-AKT), Phosphorylated mTOR (p-mTOR), MMP-2, MMP-9 and Ki-67 expression levels were evaluated by immunohistochemistry on tissue microarrays containing 200 HCCs with paired adjacent non-cancerous liver tissues. PTEN, MMP-2 and MMP-9 mRNA levels were determined by real-time RT-PCR in 36 HCCs. The relationships between PI3K/PTEN/AKT/mTOR pathway and clinicopathological factors and MMP-2, 9 were analyzed in HCC.

RESULTS

In HCC, PTEN loss and overexpression of p-AKT and p-mTOR were associated with tumor grade, intrahepatic metastasis, vascular invasion, TNM stage and high Ki-67 labeling index (P < 0.05). PTEN loss was correlated with p-AKT, p-mTOR and MMP-9 overexpression. Furthermore, PTEN and MMP-2, 9 mRNA levels were down-regulated and up-regulated in HCC compared with paired non-cancerous liver tissues, respectively (P < 0.01). PTEN, MMP-2 and MMP-9 mRNA levels were correlated with tumor stage and metastasis. There was an inverse correlation between PTEN and MMP-9 mRNA expression. However, PI3K/PTEN/AKT/mTOR pathway was not correlated with MMP-2.

CONCLUSIONS

PI3K/PTEN/AKT/mTOR pathway, which is activated in HCC, is involved in invasion and metastasis through up-regulating MMP-9 in HCC.

Bone morphogenetic protein-2 enhances the motility of chondrosarcoma cells via activation of matrix metalloproteinase-13

Chondrosarcoma is a low-grade sarcoma characterized by developing metastases and high local recurrence rate. Bone morphogenetic protein-2 (BMP-2) plays an essential role in tumor progression and metastasis. Here we found that BMP-2 induced the migration of human chondrosarcoma cells (JJ012 cells). BMP-2 also increased the secretion of metalloproteinase-13 (MMP-13) in JJ012 cells, as shown by reverse transcriptase-polymerase chain reaction, western blot and zymographic analysis. The MMP-13 small interfering RNA inhibited the BMP-2-induced MMP-13 expression and thereby significantly inhibited the BMP-2-induced cell migration. Furthermore, phosphatidylinositol 3-kinase inhibitor (PI3K; Ly294002) or Akt inhibitor suppressed BMP-2-induced MMP-13 mRNA expression. Transient transfection with dominant negative p85 and Akt mutant also showed that the PI3K/Akt signaling pathway was involved in BMP-2-induced MMP-13 expression. In addition, AP-1 decoy oligodeoxynucleotide also suppressed the MMP-13 promoter activity enhanced by BMP-2. Moreover, BMP-2 increased the binding of c-Fos and c-Jun to the AP-1 element on the MMP-13 promoter. Taken together, our results indicated that BMP-2 enhanced the invasiveness of chondrosarcoma cells by increasing MMP-13 expression through the PI3K, Akt, c-Fos/c-Jun and AP-1 signal transduction pathway.

Stromal cell-derived factor-1 increase alphavbeta3 integrin expression and invasion in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. The stromal cell-derived factor 1 (SDF-1), constitutively secreted by human lung epithelium cells, has been shown to function in a key role for recruitment of neutrophils. Here, we found that human chondrosarcoma tissues and chondrosarcoma cell lines had significant expression of CXCR4 (SDF-1 receptor), which was higher than normal cartilage and human chondrocyte. SDF-1alpha and lung epithelium cells conditioned medium (LECM) induced the invasiveness of chondrosarcoma cells. SDF-1 siRNA inhibited LECM-induced invasion of chondrosarcoma cells and SDF-1alpha also directly induced the cell surface expression of alphavbeta3 but not alpha2beta1 and alpha5beta1 integrin. Activations of ERK and NF-kappaB pathways after SDF-1 treatment was demonstrated, and SDF-1alpha-induced expression of alphavbeta3 integrin and invasion activity was inhibited by the specific inhibitor and mutant of ERK and NF-kappaB cascades. Taken together, our results indicate that lung derived-SDF-1alpha enhances the invasiveness of chondrosarcoma cells by increasing alphavbeta3 integrin expression through the CXCR4/ERK/NF-kappaB signal transduction pathway.

Establishment of a highly metastatic tongue squamous cell carcinoma cell line from New Zealand White rabbit

OBJECTIVE

Prior to this study, the widely used tongue squamous cell carcinoma cell lines could only initiate tumours in immunodeficient mice, which greatly delayed studies on immune function during carcinogenesis. This study established a new tongue squamous cell carcinoma cell line named 'RSCC-1', which can initiate tumours in both immunocompetent rabbits and immunodeficient nude mice and has high metastatic ability.

DESIGN

Primary tongue cancer was induced by DMBA and local mechanical stimulation in New Zealand White rabbits. The induced cancer was serially transplanted into homogeneous rabbits to establish transplanted models. At the same time, cancer samples were collected, cultured and passaged in vitro. Finally, a cell line named 'RSCC-1' was established. Its growth behaviour, cell cycle distribution and tumourigenicity in rabbits and nude mice were investigated.

RESULTS

RSCC-1 cells were cultured continuously in vitro for 19 months (165 passages). They contain between 54 and 196 chromosomes, with a modal number of 75. Tumourigenicity rates were 100% in both homogeneous rabbits and nude mice, with 20% lung metastasis and 50% cervical lymph node metastasis in homogeneous rabbits.

CONCLUSION

RSCC-1 is a poorly differentiated, highly malignant rabbit tongue squamous cell carcinoma cell line. Its behaviour in the inoculated animal model closely resembles human tongue cancer, and could metastasize to local lymph nodes and remote organs.

Blockade of Rho/Rho-associated coiled coil-forming kinase signaling can prevent progression of hepatocellular carcinoma in matrix metalloproteinase-dependent manner

AIM

There is growing evidence that the Rho/Rho-associated coiled coil-forming kinase (ROCK) signaling pathway is upregulated in tumors and plays a key role in cancer invasion and metastasis. Our aim was to test the anticancer effects of Rho/ROCK inhibitor, Y-27632, including possible mechanisms in a highly-metastasizing hepatocellular carcinoma (HCC) mouse model on its secretion of matrix metalloproteinase (MMP) and tumor progression.

METHODS

Following orthotopic implantation of CBO140C12 HCC tumor fragments into the liver of mice, the mice were randomly assigned to a Y-27632-treated group or control group. After treatment for 4 weeks, specimens were obtained to evaluate tumor size, metastases, and immunohistochemical findings. In vitro, we examined the effects of Y-27632 and RhoC siRNA on MMP-2 and -9 expressions, invasiveness, and apoptosis in cultured tumor cells.

RESULTS

Both RhoA and RhoC were upregulated in HCC-bearing livers, and Y-27632 significantly inhibited not only tumor growth and intrahepatic metastasis (P < 0.05), but also tumoral MMP-9 expression. Moreover, Y-27632 treatment resulted in large necrotic areas in tumors. In vitro, Y-27632 and RhoC siRNA reduced MMP-2 and -9 expressions, as well as the chemotactic migration of tumor cells dose-dependently, and increased apoptosis eight times.

CONCLUSION

Y-27632 suppresses progression and limits the intrahepatic metastasis of established HCC. This could be linked to the decreased MMP expression and induction of apoptosis in tumor cells. Rho signaling may prove to be a productive target in anticancer therapy.