Human Fc receptor-like 5 interacts with key signaling proteins in B cells (P1116)

B cell response is modulated by an array of co-receptors which transduce activating and/or inhibitory signals. The balance of these stimuli will determine cell function and fate. Human Fc receptor-like 5 (FCRL5) is a transmembrane protein containing immunoglobulin superfamily domains and is expressed by distinct subsets of B cells. The functional role of FCRL5 is poorly understood. However FCRL5 has been reported to be upregulated in several B cell tumors, including hairy cell leukemia, mantle cell lymphoma and multiple myeloma. The cytoplasmic tail of FCRL5 has two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and one predicted imunoreceptor tyrosine-based activation motif (ITAM). Both ITIMs were shown to interact with the protein phosphatase SHP-1 upon co-ligation of the B cell antigen receptor (BCR) and FCRL5, inhibiting calcium mobilization and tyrosine phosphorylation. Using Rec-1 FCRL5-positive cells and Daudi cells which have been transfected to stably express FCRL5, we investigated signaling components and pathways engaged upon FCRL5 stimulation. We found that FCRL5 forms protein complexes with phospholipase C (PLC) gamma 2 and CD19. CD19 is a well established positive regulator of BCR signaling, whereas PLC gamma 2 is critical for calcium flux in B cells. Therefore our findings could be part of the mechanism by which FCRL5 regulates B cell activation through signal transduction and calcium mobilization.

Human Fc receptor-like 5 binds intact IgG via mechanisms distinct from those of Fc receptors

Fc receptor-like (FCRL) 5 regulates B cell Ag receptor signaling and has been reported to bind aggregated IgG. Using surface plasmon resonance, we analyzed the interaction of native IgG samples with FCRL5, revealing a complex binding mechanism, where isotype is just one factor. FCRL5 bound IgG1 and IgG4 with ~1 μM KD, whereas the interaction with IgG3 was a magnitude weaker. However, IgG2 samples displayed a wide range of affinities, indicating that additional factors affect binding. We used a panel of 19 anti-FCRL5 mAbs with defined reactivity to identify domains involved in ligand binding. Six mAbs blocked IgG binding, indicating critical roles of FCRL5 domains 1 and 3, as well as epitopes at the domain 1/2 and domain 2/3 boundaries. We found that only glycosylated IgG containing both Fab arms and the Fc region bound with high affinity. Furthermore, the presence of sialic acid in the IgG carbohydrate altered FCRL5 binding. The interaction of IgG and FCRL5 consisted of two kinetic components, suggesting a complex binding mechanism. We established that the IgG-Fc and IgG-F(ab')2 fragments bind FCRL5 independently but with low affinity, revealing the mechanism behind the two-step binding of whole IgG. This complex binding mechanism is distinct from that of Fc receptors, which bind through the Fc. We propose that FCRL5 is a new type of receptor that recognizes intact IgG, possibly enabling B cells to sense Ig quality. Recognition of undamaged IgG molecules by FCRL5 could allow B cells to engage recently produced Abs.

Fc receptor-like 5 promotes B cell proliferation and drives the development of cells displaying switched isotypes

The biological roles of B cell membrane proteins in the FCRL family are enigmatic. FCRL proteins, including FCRL5, were shown to modulate early BCR signaling, although the subsequent, functional consequences of receptor engagement are poorly understood. We found that FCRL5 surface protein itself was induced temporarily upon BCR stimulation of human, naive B cells, indicating precise control over timing of FCRL5 engagement. Cross-linking of FCRL5 on cells induced to express FCRL5 enhanced B cell proliferation significantly. This enhancement required costimulation of the BCR and TLR9, two signals required for optimal proliferation of naive B cells, whereas T cell help in the form of anti-CD40 and IL-2 was dispensable. In addition, we found that FCRL5 stimulation generated a high proportion of cells displaying surface IgG and IgA. Optimal development of cells expressing switched isotypes required T cell help, in addition to stimuli found necessary for enhanced proliferation. Surprisingly, cells that developed upon FCRL5 stimulation simultaneously displayed surface IgM, IgG, and IgA. Cells expressing multiple Ig isotypes were described in hairy cell leukemia, a disease in which FCRL5 is overexpressed. Enhanced proliferation and downstream isotype expression upon FCRL5 stimulation could reflect a physiological role for FCRL5 in the expansion and development of antigen-primed B cells. In addition, FCRL5 may promote growth of malignant cells in hairy cell leukemia and other FCRL5-expressing tumors.

Tumor-evoked regulatory B cells promote breast cancer metastasis by converting resting CD4⁺ T cells to T-regulatory cells

Pulmonary metastasis of breast cancer requires recruitment and expansion of T-regulatory cells (Treg) that promote escape from host protective immune cells. However, it remains unclear precisely how tumors recruit Tregs to support metastatic growth. Here we report the mechanistic involvement of a unique and previously undescribed subset of regulatory B cells. These cells, designated tumor-evoked Bregs (tBreg), phenotypically resemble activated but poorly proliferative mature B2 cells (CD19(+) CD25(High) CD69(High)) that express constitutively active Stat3 and B7-H1(High) CD81(High) CD86(High) CD62L(Low) IgM(Int). Our studies with the mouse 4T1 model of breast cancer indicate that the primary role of tBregs in lung metastases is to induce TGF-β-dependent conversion of FoxP3(+) Tregs from resting CD4(+) T cells. In the absence of tBregs, 4T1 tumors cannot metastasize into the lungs efficiently due to poor Treg conversion. Our findings have important clinical implications, as they suggest that tBregs must be controlled to interrupt the initiation of a key cancer-induced immunosuppressive event that is critical to support cancer metastasis.

Cancer cells utilize a novel regulatory subset of B cells to promote escape and metastasis (100.26)

B cells play an important role in antigen presentation and antibody production. However, they appear to exhibit suppressive function inhibiting autoimmune responses in mice. Yet, it remains unknown whether regulatory B cells exist or participate in cancer progression. Here, we demonstrate that a unique B cel subset is induced from resting B cells by cancer cells. These B cells, designated as tumor Bregs (tBregs), are poorly proliferative and express high level of IL-2Rα. The major function of tBregs is to suppress T cell responses, as they efficiently and in dose dependent manner inhibits a proliferation of T cells stimulated with anti-CD3/28 beads. The suppressive activity of tBregs is a cell contact-dependent, but Fas/FasL- and PD1/B7H1-independent, and unlike any other reported regulatory cells, does not require soluble factors such as IL-2, IL-10, TGFβ, IL-27 and IL-35. Importantly, we show for the first time, tBregs induce a conversion of Tregs from non-regulatory CD4+ T cells. Taken together, tBregs are an important and distinct subset of regulatory cells which promote cancer escape and metastasis through direct and indirect (via Tregs) suppression of cellular responses. This work was supported by the Intramural Research Program of the National Institute on Aging, NIH.

BCR mediated c-Rel induction facilitates NF-κB2 and RelB expression (84.22)

B cell receptor (BCR) and B cell activating factor receptor (BAFF-R) signaling are critical for the generation of mature splenic B cells. BCR expressing Transitional type 1 (T1) cells migrate from the bone marrow to the spleen where they must successfully pass BCR mediated checkpoints to become Transitional type 2 (T2) cells and subsequently mature follicular B (FoB) cells. T1 and T2 cells are fundamentally different in their response to BCR or BAFF-R stimulation; T1 cells do not survive whereas T2 cells do when triggered through BCR or BAFF-R. Our results demonstrate that Bruton’s tyrosine kinase (Btk) plays a critical role in both BCR and BAFF-R mediated T2 and mature B cell survival. These results suggest that a potential mechanism that provides T2 cells with a survival advantage is their ability to sustain c-Rel expression in response to BCR engagement via mechanisms involving Btk. The increased c-Rel expression coincides precisely with the up-regulation of anti-apoptotic members of the Bcl-2 family as well as BAFF-R and its substrate p100 (NF-κB2). Thus, BCR indirectly enhances the survival function of BAFF-R in part through c-Rel. Consistent with a supporting role for BCR/c-Rel signaling in the activation of alternative NF-κB pathway, c-Rel-deficient B cells are impaired for BCR-induced expression of p100 as well as RelB.

Kinetic and function of c-Rel in naïve B cells (84.4)

Temporal control of NF-κB activation has been proposed to play an important role in response of cells to NF-κB -inducing stimuli. Our earlier studies found two phases of NF-κB activation in primary B lymphocytes stimulated via the B cell receptor. Phase I NF-κB is induced via the canonical pathway and leads to transient nuclear expression of RelA and c-Rel. Phase II NF-κB activation is mediated by de novo c-Rel gene transcription and translation. We have followed up these observations to determine the function and mechanism of c-Rel during each phase. Using a combination of biochemical, gene expression studies and gene reconstitution studies we propose that c-Rel provides unique survival functions during both phases of NF-κB activation, and supports cell cycle progression in response to CD40 stimulation in phase II. Our studies help to de-convolute functions of c-Rel that are unique from those that are redundant with RelA in B lymphocytes.

Single round of antigen receptor signaling programs naive B cells to receive T cell help

To simulate transient B cell activation that is the likely initiator of T-dependent responses, we examined the molecular and functional consequences of a single round of immunoglobulin M (IgM) signaling. This form of activation triggered early cytosolic signaling and the transcription factor NF-kappaB activation indistinguishably from conventional continuous IgM crosslinking but did not induce G1 progression. However, single round IgM signaling changed the expression of chemokine and chemokine receptor genes implicated in initiating T-dependent responses, as well as accentuated responsiveness to CD40 signaling. Several features of single-round IgM signaling in vitro were recapitulated in B cells after short-term exposure to antigen in vivo. We propose that transient BCR signals prime B cells to receive T cell help by increasing the probability of B-T encounter and creating a cellular environment that is hyper-responsive to CD40 signaling.

B cell receptor-mediated sustained c-Rel activation facilitates late transitional B cell survival through control of B cell activating factor receptor and NF-kappaB2

Signaling from the BCR and B cell activating factor receptor (BAFF-R or BR3) differentially regulates apoptosis within early transitional (T1) and late transitional (T2; CD21(int)-T2) B cells during selection processes to generate mature B lymphocytes. However, molecular mechanisms underlying the differential sensitivity of transitional B cells to apoptosis remain unclear. In this study, we demonstrate that BCR signaling induced more long-term c-Rel activation in T2 and mature than in T1 B cells leading to increased expression of anti-apoptotic genes as well as prosurvival BAFF-R and its downstream substrate p100 (NF-kappaB2). Sustained c-Rel activation required de novo c-Rel gene transcription and translation via Btk-dependent mechanisms. Like T1 cells, mature B cells from Btk- and c-Rel-deficient mice also failed to activate these genes. These findings suggest that the gain of survival potential within transitional B cells is dependent on the ability to produce a long-term c-Rel response, which plays a critical role in T2 B cell survival and differentiation in vivo by inducing anti-apoptotic genes, BAFF-R and NF-kappaB2, an essential component for BAFF-R survival signaling. Thus, acquisition of resistance to apoptosis during transitional B cell maturation is achieved by integration of BCR and BAFF-R signals.

Aberrant expression of connexin 26 is associated with lung metastasis of colorectal cancer

PURPOSE

Connexin 26 (Cx26) is one of the gap junction-forming family members classically considered to be tumor suppressors. However, recent studies show association of elevated expression of Cx26 with poor prognosis in several human malignancies. Furthermore, Cx26 has been observed to be indispensable to spontaneous metastasis of melanoma cells. Here, we assessed Cx26 expression in primary colorectal cancer (CRC) and the metastatic lesions to elucidate its role in metastasis.

EXPERIMENTAL DESIGN

Cx26 expression was assessed in 25 adenomas, 167 CRCs, and normal mucosa, together with the metastatic lesions.

RESULTS

Normal mucosa and adenomatous tissue expressed Cx26 mainly in the plasma membrane, whereas cancer cells mostly contained Cx26 in the cytoplasm. The incidence of aberrant Cx26 expression varied widely in CRC (mean, 49.5 +/- 35.5%), and the expression levels were confirmed by Western blot and quantitative reverse transcription-PCR. Clinicopathologic survey revealed association of high expression with less differentiated histology and venous invasion (P = 0.0053 and P = 0.0084, respectively). Notably, high Cx26 expression was associated with shorter disease-free survival and shorter lung metastasis-free survival in 154 curatively resected CRC sets (P = 0.041 and P = 0.028, respectively). Survey of metastatic lesions revealed that lung metastasis, but not liver and lymph nodes metastases, expressed higher Cx26 than the CRC series or corresponding primary CRCs (P < 0.0001 and P = 0.0001, respectively).

CONCLUSIONS

These findings suggest that aberrant expression of Cx26 plays an essential role in lung metastasis. Thus, Cx26 is a promising therapeutic target, particularly for CRC patients who develop lung metastasis.

Antisense to cyclin D1 inhibits vascular endothelial growth factor-stimulated growth of vascular endothelial cells: implication of tumor vascularization

PURPOSE

Our aim was to determine the effects of cyclin D1 inhibition on tumor-associated neovascularization and endothelial cell growth.

EXPERIMENTAL DESIGN

We have generated adenovirus system for antisense to cyclin D1 (AS CyD1) and evaluated in vitro and in vivo effects. Small interfering RNA against cyclin D1 was also used to analyze cyclin D1 inhibition-associated vascular endothelial growth factor (VEGF) regulation.

RESULTS

The xenografts treated with adenoviral AS CyD1 showed less vessel density and displayed smaller tumor size in colon cancer cell lines HCT116 and DLD1. In vitro studies indicated that AS CyD1 decreased VEGF protein expression in DLD1 but not in HCT116. Cyclin D1 small interfering RNA caused a decrease in VEGF expression at protein and RNA levels in DLD1. A modest decrease was noted in the VEGF promoter activity, with inactivation of the STAT3 transcription factor through dephosphorylation. On the hand, the cyclin D1 inhibition plus STAT3 inhibitor markedly decreased VEGF expression in HCT116, although VEGF did not change by the STAT3 inhibitor alone. In cultures of human umbilical vein endothelial cells (HUVEC), VEGF augmented cyclin D1 expression and cell growth. AS CyD1 significantly inhibited HUVEC growth even in the presence of VEGF. AS CyD1 also significantly suppressed in vitro tube formation in VEGF-treated HUVEC and in vivo macroaneurysm formation in VEGF-treated Matrigel plug.

CONCLUSIONS

Our results suggest that cyclin D1 may play a role in the maintenance of VEGF expression and that AS CyD1 could be potentially useful for targeting both cancer cells and their microenvironment of tumor vessels.

Combination therapy of interferon-alpha and 5-fluorouracil inhibits tumor angiogenesis in human hepatocellular carcinoma cells by regulating vascular endothelial growth factor and angiopoietins

We recently reported that interferon-alpha (IFN-alpha) and 5-fluorouracil (5-FU) combination therapy in advanced hepatocellular carcinoma (HCC) achieved excellent clinical results. However, the mechanism underlying this combination therapy remains to be elucidated. In this study, we examined the anti-tumor effects of IFN-alpha and 5-FU combination therapy in vivo and aimed to reveal its anti-angiogenic effects by investigating the expression of vascular endothelial growth factor (VEGF) and angiopoietins (Ang-1 and Ang-2). Human HCC cells, HuH7, were subcutaneously injected in nude mice. Ten days later, groups of mice received treatment with IFN-alpha alone, 5-FU alone, or with a combination of IFN-alpha and 5-FU for four weeks. Immunohistochemical examinations of proliferating cell nuclear antigen (PCNA), cell differentiation antigen 34 (CD34), Ang-1, -2 and VEGF, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and quantification of VEGF, Ang-1 and-2 mRNA using real-time RT-PCR were performed. Results showed that IFN-alpha and 5-FU combination therapy significantly inhibited the growth of human HCC cells compared with the control group or single agent treatment. The combination therapy decreased PCNA-positive cells as well as microvessel density (MVD) and induced apoptosis of (TUNEL-positive cells) more than other treatment groups. Immunohistochemical analysis revealed that the combination therapy significantly decreased the expression of VEGF and Ang-2 and increased that of Ang-1. The ANG2/ANG1 mRNA expression ratio was significantly lower in the combination therapy group. In conclusion, our results suggested that IFN-alpha and 5-FU combination therapy has anti-proliferative and anti-angiogenic effects and can induce apoptosis in vivo. The synergistic and anti-angiogenic effects may in part be attributable to the regulation of Ang-1, -2 and VEGF.

Combined intra-arterial 5-fluorouracil and subcutaneous interferon-alpha therapy for highly advanced hepatocellular carcinoma

Because of the difficulties of low sensitivity for anticancer agents and giving sufficient dose because of poor liver function, chemotherapy may not play a central role for treatment of hepatocellular carcinoma (HCC) patients, especially those with liver cirrhosis. However, chemotherapy must be one of the important possibilities of multimodal treatment for advanced HCC, for which hepatic resection, percutaneous ablation, transcatheter arterial embolization and other general therapies would not be effective or even possible. Also, intra-arterial perfusion chemotherapy is a common therapy for HCC and it is not difficult to maintain; but the effective rate is not sufficient. Recently, the combination therapy of s.c. interferon (IFN)-alpha and intra-arterial 5-fluorouracil (5-FU) showed an outstandingly effective rate for intractable HCC (with portal vein thrombosis). In addition,recent preclinical and clinical studies have revealed that the mechanism of combination therapy may concern direct antitumor effects (through cell-cycle arrest and induction of apoptosis) and indirect actions (through immunocompetent cells and anti-angiogenic effect). For the further advance of HCC treatment and prognosis, this therapy might be a promising treatment modality and is expected to develop. In this review, we summarize recent clinical and preclinical data regarding IFN-alpha and 5-FU combination therapy and discuss the further prospects of this therapy.

Complete remission of hepatocellular carcinoma with portal vein tumor thrombus and lymph node metastases by arterial infusion of 5-fluorouracil and interferon-alpha combination therapy following hepatic resection

We report two cases of hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) and lymph node (LN) metastases successfully treated by hepatic arterial infusion of 5-fluorouracil (5-FU) combined with systemic injection of interferon (IFN)-alpha following hepatic resection for the liver tumor. Complete remission was obtained. Case 1 was a 51-year-old man who had HCC in the right lobe of the liver with PVTT and multiple intrahepatic metastases. He also had abdominal and mediastinal LN metastases. Case 2 was a 53-year-old man who had diffuse-type HCC in the right lobe of the liver with PVTT and intrahepatic metastases. A chest computed tomography scan revealed lymph nodes enlarged to 1.0 cm from the mediastinum to the left supraclavicular space. Both patients underwent the hepatectomy to reduce the tumor volumes and remove the PVTT to relieve portal vein obstruction. Following the surgery, the patients underwent IFN-alpha/5-FU combination therapy. Three months after this combined therapy, tumor markers (both alpha-fetoprotein and protein induced by vitamin K absence or antagonist II) returned to the normal range and residual tumors in the liver disappeared. The patients are alive without any recurrence more than 1 year after initial treatment. IFN-alpha/5-FU combined therapy following hepatic resection is a promising modality for the treatment of advanced HCC with LN metastasis.

Successful treatment of multiple hepatocellular carcinoma with tumor thrombi in the major portal branches by intraarterial 5-fluorouracil perfusion chemotherapy combined with subcutaneous interferon-alpha and hepatectomy

We experienced a patient who received successful treatment for multiple hepatocellular carcinoma (HCC) nodules, with tumor thrombi in the major portal branches, with intraarterial 5-fluorouracil perfusion chemotherapy combined with subcutaneous interferon-alpha administration. The patient was a 50-year-old man with hepatitis C virus and HCC. The tumors consisted of a 5-cm main nodule in the right lobe (segment 8) and multiple intrahepatic metastases. The tumor also involved portal vein thrombosis throughout the right portal branch. After two cycles of interferon-alpha/5-fluorouracil combination chemotherapy, tumor markers demonstrated a decreasing tendency. Nine months after the initiation of this therapy, the tumors were limited to the right lobe and were surgically removed by S8 subsegmentectomy, S5 partial hepatectomy, and portal thrombectomy. The serum levels of both alpha-fetoprotein and protein induced by vitamin K absence II fell to normal levels after hepatic resection. Fifty-eight months after the first treatment, he is alive with several recurrent nodules in the liver. In conclusion, the interferon-alpha/5-fluorouracil combination therapy is a useful treatment for HCC in patients who have multiple intrahepatic metastases and portal vein thrombosis. In addition to this therapy, combined modality therapy including, for example, surgical resection, can sometimes have a dramatic therapeutic effect, shown by tumor markers reverting to normal levels.

Patterns and clinicopathologic features of extrahepatic recurrence of hepatocellular carcinoma after curative resection

BACKGROUND

Little is known about the metastatic pattern in patients with extrahepatic metastasis after the removal of primary hepatocellular carcinoma (HCC). The aim of the present study was to determine the clinicopathologic characteristics and prognosis of patients with extrahepatic metastasis from HCC according to the recurrence pattern.

METHODS

Among the patients who underwent hepatic resection for HCC between 1981 and 2001, 80 patients had no recurrence; 221 patients had intrahepatic recurrence, and 47 patients experienced extrahepatic metastasis within a mean follow-up period of 4.8 +/- 3.7 years (+/-SD; range, 2-15 years). The pattern of extrahepatic metastasis after hepatic resection was divided into pattern I (first recurrence in the liver and then spread outside the liver after repetitive intrahepatic recurrences and repetitive locoregional treatments), pattern II (simultaneous recognition of intrahepatic and extrahepatic recurrences), and pattern III (extrahepatic, but no intrahepatic, lesions at first recurrence).

RESULTS

There were significant differences in proportions of patients with invasion of the portal vein, hepatic vein, or inferior vena cava, intrahepatic metastases, and tumor stage between patients with intra- and extrahepatic metastases. The disease-free survival and extrahepatic metastasis-free survival in pattern I were better than pattern II. Survival after extrahepatic metastasis did not correlate with the 3 patterns.

CONCLUSION

Although long-term overall survival was better in patients with pattern I of extrahepatic recurrences, prognosis was poor in all patterns once extrahepatic metastasis developed.

Overexpression of MT3-MMP in hepatocellular carcinoma correlates with capsular invasion

BACKGROUND/AIMS

Extracellular matrix-degrading matrix metalloproteinases (MMPs) are invariably up-regulated in epithelial cancers and are key agonists of angiogenesis, invasion and metastasis. Recent studies have shown high levels of various MMPs, including MT1-MMP, MMP-1, MMP-2 and MMP-9, and their involvement in tumor progression in human hepatocellular carcinoma (HCC). However, the expression and role of MT3-MMP in HCC remains unclear.

METHODOLOGY

We examined the immunohistochemical expression of MT3-MMP in surgically resected HCCs (n=58), hepatitis C virus (HCV) and hepatitis B virus (HBV)-related chronic hepatitis (n=34) and cirrhosis (n=24).

RESULTS

MT3-MMP expression was observed in all non-cancerous liver tissues. In HCCs, 52% (30/58) of patients showed high MT3-MMP expression while the remaining 48% (28/58) of patients showed low expression. A clinicopathological survey demonstrated a significant correlation between high MT3-MMP expression and capsular invasion of carcinoma (p = 0.034) although there was no correlation between high MT3-MMP expression in HCC and overall survival or disease-free survival.

CONCLUSIONS

MT3-MMP was expressed not only in chronic hepatitis and liver cirrhosis, but also in HCC, and high MT3-MMP expression correlated significantly with capsular invasion of carcinoma.

Stronger growth-inhibitory effect of interferon (IFN)-beta compared to IFN-alpha is mediated by IFN signaling pathway in hepatocellular carcinoma cells

Interferon (IFN) is a promising drug for prevention and treatment of hepatocellular carcinoma (HCC) in combination with chemotherapeutic agents. We previously reported that the spectra of antiproliferative activity and synergistic effect of IFN-beta when combined with anticancer drugs are more potent than those of IFN-alpha in HCC cells. However, the mechanism of the diverse antitumor effects of the IFNs is not understood yet. We studied the expression of IFN alpha receptor 2 (IFNAR2), STATs, and IFN-alpha, IFN-beta's growth-inhibitory effect, signal transduction and binding to IFNAR2 on three HCC cell lines and a tumor xenografted mouse model (12 animals/group). From the results, IFN-beta showed a significantly stronger growth-inhibitory effect than IFN-alpha on the HuH7 cell line (expressing low IFNAR2), however it was similarly high on PLC/PRF/5 and weak on HLE. In the nude mouse tumor xenograft model, IFN-beta injection significantly suppressed tumor volume relative to vehicle injection, while IFN-alpha showed weaker growth-inhibition. IFN signal transduction (phosphorylated-STAT1, 3) induced by IFN-beta was higher than that by IFN-alpha in HuH7 and tumor xenografts. Pretreatment of hepatoma cells with anti-IFNAR2 antibody blocked the IFN signaling, more for IFN-alpha. IFN-alpha's antiproliferative effect was reduced by the antibody in lower concentrations compared to that of IFN-beta. Taken together, the HCC cells that express low IFNAR2 and are resistant to IFN-alpha were sensitive to the growth-inhibitory effect of IFN-beta, which might be mediated by stronger IFN signal transduction and distinct binding to IFNAR compared to IFN-alpha.

Role of the Fas/FasL pathway in combination therapy with interferon-alpha and fluorouracil against hepatocellular carcinoma in vitro

BACKGROUND/AIMS

Several studies have reported the efficacy of combination therapy of interferon (IFN) alpha and 5-fluorouracil (5-FU) for hepatocellular carcinoma (HCC). However, the mechanism underlying the clinical anti-tumor effects of this treatment is not well understood. The aim of this study was to determine the role of Fas/FasL signaling in the anti-tumor effect of this combination therapy.

METHODS AND RESULTS

We used six human hepatoma cell lines, three of which are known Fas-expressing cells. Growth of Fas-positive hepatoma cell lines was inhibited by an agonistic anti-Fas antibody in a dose-dependent manner, and these effects were enhanced by IFNalpha or 5-FU alone, but even more so by combination therapy using both agents. Annexin-V assay implicated apoptosis as the main mechanism underlying these growth inhibitory effects, although changes in Fas expression regulated by IFNalpha and/or 5-FU did not correlate with increased apoptosis. Caspase-3 activation was exclusively increased by IFNalpha/5-FU combination treatment, which was compatible with enhancement of the synergistic apoptotic effect, and other caspases and apoptotic factors (FLIP, BCL-xl, and Bax) were also regulated by IFNalpha/5-FU. 51Cr-release assay revealed that pretreatment with IFN activated cytotoxicity of peripheral blood mononuclear cells (PBMCs) against HCC cells. The largest interaction was observed when both PBMC and HCC cells were pretreated with the combination of IFNalpha/5-FU. These cytotoxicities were markedly inhibited by a neutralizing anti-Fas antibody.

CONCLUSIONS

Our results indicated that IFNalpha/5-FU combination treatment enhances the induction of apoptosis and the cytotoxic effect of PBMCs via the Fas/FasL pathway. The Fas/FasL pathway seems, at least in part, to contribute to the anti-tumor effects of IFNalpha/5-FU against HCCs.

Interferon alpha receptors are important for antiproliferative effect of interferon-alpha against human hepatocellular carcinoma cells

AIM

Interferon (IFN)-alpha is a promising drug for the prevention and treatment of hepatocellular carcinoma (HCC). We reported that responders to IFN-alpha/5-fluorouracil combination therapy expressed higher IFN alpha receptor (IFNAR)2 in tumor. Herein we studied involvement of IFNARs in response to IFN-alpha in HCC cells.

METHODS

IFN-alpha sensitivity and expression of IFNARs were studied in six HCC cell lines (HuH7, PLC/PRF/5, HLE, HLF, HepG2, Hep3B) using growth-inhibitory and RT-PCR, Western blot assays. Short interfering RNAs (SiRNAs) against IFNAR1 and 2 were used to analyze the role of the IFNARs in IFN-alpha's effect and signal transduction.

RESULTS

The expressions of IFNAR1 and 2c mRNAs were higher in PLC/PRF/5 cells than those in other cell lines, and PLC/PRF/5 cells expressed abundant IFNAR2c on their cell membrane. When we examined the sensitivity of the HCC cell lines to the growth-inhibitory effect of IFN-alpha, PLC/PRF/5 exhibited a significant response, while the other cells were much more resistant. Knockdown of either IFNAR1 or 2 using siRNAs suppressed the IFN-alpha's signal transduction (2.5-fold), and decreased the growth-inhibitory effect (down by 69.9% and 67.3%).

CONCLUSION

The results suggest that the expression of IFNAR1 and IFNAR2c independently are important for the antiproliferative effect of IFN-alpha in HCC cells.

A case of hepatocellular carcinoma with multiple lung, spleen, and remnant liver metastasis successfully treated by combination chemotherapy with the novel oral DPD-inhibiting chemotherapeutic drug S-1 and interferon-alpha

A 54-year-old man was admitted Osaka University Hospital for hepatocellular carcinoma (HCC) with portal vein thrombus and multiple intrahepatic metastases that extended to the bilateral lobes of the liver. He underwent multimodal therapy, including extended left lobectomy followed by intra-arterial 5-fluorourcil (5-FU) infusion chemotherapy combined with subcutaneous interferon-alpha (IFN-alpha) to treat the lesions in the residual liver. Seven months after the initial resection, recurrent tumors in the spleen, lung, and residual liver were detected by follow-up examination. We started a new regimen of per oral administration of S-1 and subcutaneous IFN-alpha injection, because the combined therapy with intra-arterial 5-FU infusion was not considered effective for distant metastases. After two cycles of S-1 and IFN-alpha, the metastatic tumor in the spleen and the recurrence in the residual liver had disappeared, and the diagnosis was complete remission with no adverse effect; the pulmonary metastasis showed a partial response, and was finally resected. This patient is still alive with no recurrence 32 months after initial hepatic resection. This outcome suggests that combination therapy with S-1 and IFN-alpha may be a promising treatment modality against advanced HCC with distant metastasis.

[Surgical treatment for peritoneal dissemination of hepatocellular carcinoma after percutaneous ethanol injection therapy--a case report]

We report a 73-year-old man who underwent surgery for peritoneal dissemination of hepatocellular carcinoma (HCC) after percutaneous ethanol injection therapy (PEIT). He received posterior segmentectomy for HCC in 1997. Four years after the first hepatic resection, a recurrence lesion in the right caudal lobe of the liver was detected by computed tomography (CT). He underwent percutaneous ethanol injection therapy (PEIT) and transcatheter arterial embolization (TAE). He was referred to our hospital for further treatment. Abdominal CT revealed an early-enhanced lesion (3.2 cm in size) in the right caudal lobe of the liver and an irregular mass lesion (1.5 cm in size) in the cranial. We diagnosed the disease as recurrent HCC and carried out partial hepatectomy, removal of peritoneal dissemination and a reconstruction of the inferior vena cava. A histological feature of the tumor was a moderately differentiated HCC, and there was no lymphatic structure in the tumor, and no connection to the residual liver. Therefore, we diagnosed the tumor as peritoneal dissemination of HCC. We think that this is a rare but a serious complication of PEIT and every effort should be attempted to prevent this complication, especially in the treatment of superficial and larger HCC.

[Intra arterial infusion chemotherapy combined with interferon-alpha following palliative hepatic resection against advanced hepatoma with portal venous tumor thrombus in the major trunk and multiple nodules--a preliminary study]

Recently, we reported the beneficial effects of intra arterial 5-FU infusion chemotherapy combined with interferon-alpha (IFN-alpha/5-FU combined chemotherapy) for advanced hepatocellular carcinoma (HCC). This report describes the preliminary results of treatment of IFN-alpha/5-FU combined chemotherapy following palliative hepatic resection for advanced hepatocellular carcinoma with tumor thrombus in the main trunk of the portal vein with multiple nodules in the whole liver. The 15 patients of HCC with portal venous tumour thrombi (PVTT) and multiple intra-hepatic multiple nodules (IM3) were treated with IFN-alpha/5-FU combined chemotherapy following palliative surgery in this study. No leukopenia, thrombocytopenia, or myelosuppression was observed in any of the 15 patients. Other adverse effects were, in general, clinically manageable. Concerning the anti-tumor effect, 6 showed an objective response and 9 showed a progressive disease; the response rate was 40.0% (6/15). The 1-year and 3-year survival rates were 48% and 21% in all 15 cases, respectively. In conclusion, IFN-alpha/5-FU combined therapy may be a promising modality for advanced HCC with tumor thrombi in the major trunk with multiple nodules after following palliative surgery.

[A successful case of hepatocellular carcinoma with portal venous tumor thrombus (Vp2) treated by transcatheter arterial chemoembolization]

We reported a case of hepatocellular carcinoma (HCC) with portal venous tumor thrombus (PVTT) (Vp2) successfully treated by transcatheter arterial chemoembolization (TACE), and the tumor showed complete response and the patient survived for 28 months. A 67-year-old male was diagnosed with HCC in the area of subsegment 5 with PVTT from the P5 to the posterior branch. He was treated by segmental TACE. The tumor markers decreased within normal limits, and localized hepatic infraction in the subsegment 5 and atrophy of the PVTT were recognized. He survived for 28 months with no tumor recurrence after the first TACE. This case suggested that embolization might play a part of treatment to HCC with PVTT, if the liver function was preserved and the lesion of liver infraction was limited.

Expression of PPARdelta in multistage carcinogenesis of the colorectum: implications of malignant cancer morphology

Whether peroxisome proliferator-activated receptor (PPAR) delta is a good target for the chemoprevention and/or treatment of colorectal cancer (CRC) remains controversial. Our goal was to examine PPARdelta expression in multistage carcinogenesis of the colorectum and to assess the relevance of PPARdelta in CRC. Immunohistochemical analysis indicated that PPARdelta expression increased from normal mucosa to adenomatous polyps to CRC. In cancer tissues, the PPARdelta protein was accumulated only in those cancer cells with highly malignant morphology, as represented by a large-sized nucleus, round-shaped nucleus, and presence of clear nucleoli. Interestingly, the cancer tissue often contained both PPARdelta-positive and -negative areas, each retaining their respective specific morphological features. Moreover, this pattern persisted even when PPARdelta-positive and -negative cells were aligned next to each other within a single cancer nest or gland and was present in the majority of CRC cases. Immunohistochemistry for Ki-67 proliferation marker showed no significant correlation between Ki-67 and PPARdelta in CRC samples. Based on Western blot analysis and quantitative RT-PCR, high PPARdelta protein expression correlated with high PPARdelta mRNA levels. Peroxisome proliferator-activated receptor delta may have a supporting role in tumorigenesis, and the close association between PPARdelta expression and malignant morphology of CRC cells suggests a pivotal role in cancer tissue.

Expression of type I interferon receptor as a predictor of clinical response to interferon-alpha therapy of gastrointestinal cancers

Interferon (IFN) is used in the treatment of many malignancies and viral disorders. We recently reported a significant correlation between the efficacy of IFN-alpha combined with chemotherapy in the treatment of advanced hepatocellular carcinoma (HCC) and IFN-alpha/type I IFN receptor (IFNAR2) expression. It is possible that the expression of IFNAR2 in gastrointestinal cancerous tissue, apart from HCC, may predict the efficacy of IFN-alpha combination therapy. We investigated the expression of IFNAR2 in 100 gastrointestinal cancerous tissues. IFNAR2 expression was examined using immunohistochemistry, in surgically resected tissue samples (20 esophageal, 20 gastric, 20 colorectal, 20 cholangiocarcinoma, and 20 pancreatic samples). The expression rate of IFNAR2 was 35.0% (7/20), 25.0% (5/20), 20.0% (4/20), 45.0% (9/20), and 25.0% (5/20) in esophageal, gastric cancer, colorectal, cholangiocarcinoma and pancreatic cancer samples, respectively. In our previous report, the expression rate of IFNAR2 in HCC samples was 64.8% (59/91). Thus, the expression rates of IFNAR2 in the five types of gastrointestinal cancers tested here were low, compared with HCC. The clinical efficacy of IFN-alpha mono- or combination therapies in patients with gastrointestinal neoplasms is expected to be lower than in patients with HCC based on the expression level of IFNAR2.

Vitamin K2 has growth inhibition effect against hepatocellular carcinoma cell lines but does not enhance anti-tumor effect of combination treatment of interferon-alpha and fluorouracil in vitro

Several studies have recently reported the efficacy of combination therapy of interferon (IFN) alpha and 5-fluorouracil (5-FU) for hepatocellular carcinoma (HCC). However, the clinical effect of this treatment was not complete. The new therapeutic modality should be necessary to rise up this clinical response rate. Recently, the anti-tumor effect of Vitamin K2 has been reported in terms of decreased recurrence rate of HCC patients. The aim of this study was to explore the additive or synergistic effect of Vitamin K2 to combined therapy of interferon (IFN) alpha and 5-fluorouracil (5-FU) against hepatocellular carcinoma (HCCs). The study was conducted using three hepatoma cell lines (PLC/PRF/5, Hep3B and HepG2). The 3-(4-5-dimethylthiazol-2-yl)-2, 5-dyphenyl tetrazolium bromide (MTT) assay (48h) revealed anti-tumor effect of IFNalpha and 5-FU. Cell growth assay (3-7 days) showed growth inhibitory effect of Vitamin K2 on three cell lines after day 5. But additional effect of combination treatment of Vitamin K2 and IFNalpha/5-FU was not observed in any time course from 48h to 7 days. Cell cycles were assessed with flowcytometry. Although either Vitamin K2 or IFNalpha/5-FU alone has the influence to the cell cycles, no significant change was shown in the combination of Vitamin K2 and IFNalpha/5-FU. In conclusion, Vitamin K2 itself has potentially growth inhibitory effect for HCC cell lines, but does not enhance the anti-tumor effect of IFNalpha and 5-FU.

Expression pattern of angiogenic factors and prognosis after hepatic resection in hepatocellular carcinoma: importance of angiopoietin-2 and hypoxia-induced factor-1 alpha

BACKGROUND

Hepatocellular carcinoma (HCC) is a hypervascular tumor and angiogenesis plays an important role in its progression. Angiogenesis is regulated by a balance between pro and antiangiogenic molecules. The aim of this study was to investigate the expressions of angiogenic factors and elucidate their roles in angiogenesis in HCC.

METHODS

We investigated immunohistochemical expression of vascular endothelial growth factor (VEGF), angiopoietins (Ang-1 and Ang-2), hypoxia-induced factor-1alpha (HIF-1alpha) and thrombospondin-1 (TSP-1) in 60 specimens of surgically resected HCC. We investigated the relationship between their expressions and clinicopathological factors or prognosis.

RESULTS

Ang-2 staining had a significant correlation with the grade of differentiation of HCC cells (P=0.0082). VEGF and Ang-2 expression correlated positively with microvessel density (MVD) (P=0.0061 and 0.0374, respectively). MVD of well-differentiated HCC were significantly lower than those of moderately and poorly differentiated HCC. The disease-free survival time of patients with high Ang-2 and/or HIF-1alpha expression was significantly shorter than that of the low expression group (P=0.0278 and 0.0374, respectively).

CONCLUSION

Our study showed that the expression of VEGF and Ang-2 correlated with MVD. Strong Ang-2 expression and/or high nuclear expression of HIF-1alpha is a significant predictive factor for recurrence after curative resection in HCC patients.

Angiogenesis in cholangiocellular carcinoma: expression of vascular endothelial growth factor, angiopoietin-1/2, thrombospondin-1 and clinicopathological significance

Angiogenesis in cholangiocellular carcinoma (CCC) has rarely been investigated. The aim of this study was to determine the angiogenesis status of CCC and assess its relationship with angiogenic factors and clinicopathological characteristics. We examined 33 surgically resected CCC specimens. Tumor angiogenesis was assessed by microvessel density (MVD) using the anti-CD34 antibody, and the expression of VEGF, Ang-1, Ang-2, and TSP-1 was determined by immunohistochemistry. The mean (+/- SD) MVD was 87.2+/-52.6/mm2 (range, 0-229/mm2). A total of 75.6% cases were positive for VEGF expression, 36% for Ang-1, 57.6% for Ang-2 and 45.5% for TSP-1. VEGF and Ang-2 expression was associated with a significantly higher level of MVD (p=0.004 and 0.015, respectively). TSP-1 expression was associated with a significantly lower level of MVD (p=0.005) and a higher level of intrahepatic metastasis (46.7% vs. 5.6%, p=0.012). There was no significant correlation between VEGF, Ang-1, Ang-2, and TSP-1 expression and tumor size, capsule formation, infiltration of capsule, portal vein invasion, intrahepatic metastasis or CCC differentiation. There was no significant correlation between MVD levels, VEGF, Ang-1, Ang-2, and TSP-1 expression and postoperative survival. A considerable degree of angiogenesis, comparable to that of other solid tumors, was observed in CCC. VEGF and Ang-2 might play a proangiogenic role, and TSP-1 may play an inhibitory role in CCC. Although TSP-1 may increase intrahepatic CCC metastases, neither MVD levels nor the expression of VEGF, Ang-1, or Ang-2 was associated with clinicopathological factors and prognosis.

Association between recurrence of hepatocellular carcinoma and alpha-fetoprotein messenger RNA levels in peripheral blood

PURPOSE

Intra- and extrahepatic recurrence is common, even after curative resection for hepatocellular carcinoma (HCC), suggesting preoperative or intraoperative tumor cell dissemination. Reverse transcription - polymerase chain reaction (RT-PCR) for alpha-fetoprotein (AFP) is used to detect circulating liver cancer cells. We previously developed a quantitative method that allows estimation of the AFP mRNA level by real-time PCR. In the present study, we used this method to measure the AFP mRNA level before and after resection of HCC, then correlated the findings with various clinicopathological characteristics and prognosis.

METHODS

We prospectively examined peripheral blood samples from 38 patients with HCC, and bone marrow aspirate from 25 of these patients. As a control, we examined bone marrow from 20 patients with benign diseases. The follow-up period ranged from 32 to 66 months. Real-time RT-PCR was used to detect AFP mRNA levels in the samples.

RESULTS

AFP was expressed in 9 (23.7%) of the 38 peripheral blood samples. The detection of AFP mRNA was significantly correlated with extrahepatic metastasis after primary surgery, and a shorter disease-free survival time (P = 0.0245 each). Bone marrow samples were defined as positive if they expressed AFP mRNA at levels higher than the maximum expressed level in the controls, because only 1 (5%) of the 20 control bone marrow samples had low AFP mRNA expression. Using this cutoff level, 12 (48%) of the 25 patients with HCC had positivity for AFP mRNA. The results of bone marrow RT-PCR did not correlate with the clinocopathological characteristics of prognosis.

CONCLUSIONS

Using real-time PCR to measure the AFP mRNA level in blood, but not bone marrow, could be useful for predicting postoperative tumor recurrence.

Angiogenesis in cholangiocellular carcinoma: expression of vascular endothelial growth factor, angiopoietin-1/2, thrombospondin-1 and clinicopathological significance

Angiogenesis in cholangiocellular carcinoma (CCC) has rarely been investigated. The aim of this study was to determine the angiogenesis status of CCC and assess its relationship with angiogenic factors and clinicopathological characteristics. We examined 33 surgically resected CCC specimens. Tumor angiogenesis was assessed by microvessel density (MVD) using the anti-CD34 antibody, and the expression of VEGF, Ang-1, Ang-2, and TSP-1 was determined by immunohistochemistry. The mean (+/- SD) MVD was 87.2+/-52.6/mm2 (range, 0-229/mm2). A total of 75.6% cases were positive for VEGF expression, 36% for Ang-1, 57.6% for Ang-2 and 45.5% for TSP-1. VEGF and Ang-2 expression was associated with a significantly higher level of MVD (p=0.004 and 0.015, respectively). TSP-1 expression was associated with a significantly lower level of MVD (p=0.005) and a higher level of intrahepatic metastasis (46.7% vs. 5.6%, p=0.012). There was no significant correlation between VEGF, Ang-1, Ang-2, and TSP-1 expression and tumor size, capsule formation, infiltration of capsule, portal vein invasion, intrahepatic metastasis or CCC differentiation. There was no significant correlation between MVD levels, VEGF, Ang-1, Ang-2, and TSP-1 expression and postoperative survival. A considerable degree of angiogenesis, comparable to that of other solid tumors, was observed in CCC. VEGF and Ang-2 might play a proangiogenic role, and TSP-1 may play an inhibitory role in CCC. Although TSP-1 may increase intrahepatic CCC metastases, neither MVD levels nor the expression of VEGF, Ang-1, or Ang-2 was associated with clinicopathological factors and prognosis.

TGF-beta1-induced cell growth arrest and partial differentiation is related to the suppression of Id1 in human hepatoma cells

Transforming growth factor beta 1 (TGF-beta1) is a proposed regulator of Ids (inhibitors of DNA binding/differentiation) gene expression in epithelial cells. We previously reported that Id proteins are variously expressed in human hepatocellular carcinomas (HCC). However, the mechanism of regulation of Ids in HCC remains obscure. Here, we examined the relationship between Id1 and TGF-beta1 in four HCC cell lines, and studied the changes in cell proliferation, cell cycle and differentiation. The four HCC cell lines expressed Id1, TGF-beta1 and their receptors at various levels. TGF-beta1 strongly inhibited the growth of HuH7 cells, while the growth inhibition was moderate in PLC/PRF/5, and was not observed in HLE and HLF cell lines. TGF-beta1-induced growth inhibition in HuH7 cells was associated with cell accumulation in the G1 phase and partial induction of differentiation (with reduction of AFP and AFP-L3). Induction by TGF-beta1 dose-dependently suppressed Id1 expression in HuH7 cells; 1 ng/ml TGF-beta1 inhibited Id1 by 84.0 and 78.6% that of the untreated control at transcriptional and protein levels, respectively. HLE and HLF cells, which did not exhibit a TGF-beta1 growth inhibitory effect, lacked TGF-beta receptors and Id1 expression was not altered. In PLC/PRF/5 cells, Id1 augmentation was not observed in response to TGF-beta1, indicating that TGF-beta1-induced growth inhibition was not related to Id1 in this cell line. Our results suggest that, in some HCC cells, the pathway of suppression of Id1 by TGF-beta1 may be important in TGF-beta1-induced growth inhibition and partial differentiation.

Role of p21waf1/cip1 in effects of oxaliplatin in colorectal cancer cells

Clinical studies have shown that oxaliplatin, a novel platinum derivative, is a potent chemotherapeutic agent for colorectal cancer when combined with 5-fluorouracil and leucovorin. Although the toxic activity is based on covalent adducts between platinum and DNA, its actual biological behavior is mostly unknown. In an effort to explore the mechanism of tumor susceptibility to oxaliplatin, we examined the cytotoxic effects of oxaliplatin in colorectal cancer cell lines in reference to p53 gene status. Although p53 gene status did not clearly predict sensitivity to oxaliplatin, p53 wild-type cells including HCT116 were sensitive but HCT116 p53-/- were found to be resistant to oxaliplatin. Oxaliplatin caused strong p21waf1/cip1 induction and G0-G1 arrest in p53 wild-type cells, whereas cisplatin did not induce G0-G1 arrest. Assays using p53 wild but p21waf1/cip1 null HCT116 cells revealed that oxaliplatin did not show G0-G1 arrest and reduced growth-inhibitory effects, suggesting that p21waf1/cip1 may be a key element in oxaliplatin-treated p53 wild-type cells. Although HCT116 is DNA mismatch repair-deficient, a mismatch repair-proficient HCT116+ch3 cell line displayed similar responses with regard to p21waf1/cip1-mediated growth inhibition and G0-G1 arrest. In p53 mutant cells, on the other hand, oxaliplatin caused an abrupt transition from G1 to S phase and eventually resulted in G2-M arrest. This abrupt entry into S phase was associated with loss of the p21waf1/cip1 protein via proteasome-mediated degradation. These findings suggest that p21waf1/cip1 plays a role in oxaliplatin-mediated cell cycle and growth control in p53-dependent and -independent pathways.

Treatment of hepatocellular carcinoma with major portal vein thrombosis by combined therapy with subcutaneous interferon-alpha and intra-arterial 5-fluorouracil; role of type 1 interferon receptor expression

We previously reported the beneficial effects of combination therapy of interferon (IFN)-α/5-fluorouracil (FU) for advanced hepatocellular carcinoma (HCC) with tumour thrombi in the major portal branches. This report describes the results of longer follow-up and includes more than double the number of patients relative to the original report, and evaluates the role of IFN-α/type 2 interferon receptor (IFNAR2) expression on the response to the combination therapy. The study subjects were 55 patients with advanced HCC and tumour thrombi in the major branches of the portal vein (Vp3 or 4). They were treated with at least two courses of IFN-α/5-FU without major complication. In the 55 patients, 24 (43.6%) showed objective response (eight (14.5%) showed complete response, 16 (29.1%) partial response), four (7.3%) showed no response, and 27 (49.1%) showed progressive disease. Immunohistochemically, IFNAR2 expression was detected in nine out of 13 (69.2%) patients. There was significant difference in the time-to-progression survival (P=0.0002) and the overall survival (P<0.0001) between IFNAR2-positive and -negative cases. There was a significant correlation between IFNAR2 expression and response to IFN-α/5-FU combination therapy in univariate analysis (P=0.0070). IFN-α/5-FU combination therapy is a promising modality for advanced HCC with tumour thrombi in the major portal branches and could significantly depend on IFNAR2 expression.

[A case of HCC with inferior caval vein tumor thrombus and multiple pulmonary metastases that remarkably responded to combination therapy of TS-1 and interferon-alpha]

A 56-year-old male was admitted to our hospital for hepatoma with portal vein thrombus and multiple intrahepatic metastases. He underwent an extended left lobectomy and a partial resection of the liver in May 2002. After two weeks from the surgery, he received intra arterial 5-FU infusion chemotherapy combined with subcutaneous interferon-alpha injection to treat the lesions in the residual liver. Four months after the surgery, hepatic vein tumor thrombus appeared in the remnant liver and it extended to the inferior caval vein. And another 4 months later, multiple pulmonary metastases were detected with computed tomography and they grew rapidly in the view of their sizes and numbers. Because the combined therapy of 5-FU/interferon-alpha was not effective to distant metastases, we started a new regimen of oral administration of TS-1 and a subcutaneous interferon-alpha injection. After 1 treatment cool, hepatic vein thrombus was markedly reduced the size and vascularity in the CT. Multiple pulmonary metastases also decreased in their sizes and numbers. No adverse effect was seen during this treatment. It was suggested that a combination therapy of TS-1 and interferon-alpha may be one of the most effective treatment modalities against advanced HCC with distant metastasis.

[A successful surgical treatment for solitary pulmonary and adrenal metastases after hepatic resection to hepatocellular carcinoma--a case report]

We report a 65-year-old man who received a successful surgical treatment for both pulmonary and adrenal metastases after curative resection to hepatocellular carcinoma (HCC). He received a partial hepatic resection for HCC of the right hepatic lobe. Thirty-eight months after the first hepatic resection, a metastatic lesion of the right pulmonary lobe was detected by computed tomography (CT). He was orally administered of UFT (600 mg/day). After 6 months of the chemotherapy, a metastatic lesion of lung became decreased in size. However, a metastatic lesion of the right adrenal gland was detected by abdominal CT scan. Fifty six months after the first operation, we performed right adrenalectomy. A further 4 months later, we performed partial resection of the right pulmonary lobe. Eight months after the pulmonary resection, intrahepatic recurrence was detected and he received transcatheter arterial embolization (TAE) twice. Eighty one months after the first operation, he died of liver failure due to tumor progression. Surgical resection for metastases from HCC resulted in long-term survival even if there were extrahepatic metastases in two different sites.

Effects of p21cip1/waf1 overexpression on growth, apoptosis and differentiation in human colon carcinoma cells

The cyclin-dependent kinase inhibitor p21cip1/waf1 negatively regulates the progression of cell cycle and the potential usefulness of p21cip1/waf1 gene is proposed in gene therapy. However, studies have demonstrated a protective role of p21cip1/waf1 against apoptosis and little is known about effects of ectopic expression of p21cip1/waf1 on differentiation of colon cancer cells. In the present study, we found diffuse p21cip1/waf1 expression in only a few clinical samples of colorectal cancer with wild-type p53 gene. To explore the role of p21cip1/waf1 in cell growth, apoptosis and differentiation, we constitutively overexpressed p21cip1/waf1 in HT29 colon carcinoma cells. Ectopic overexpression of p21cip1/waf1 was associated with inhibition of CDK2-associated kinase activity, indicating the functionality of the introduced p21cip1/waf1 gene. Overexpression of p21cip1/waf1 caused an appreciable growth inhibition in monolayer and soft agar cultures and it significantly reduced sodium butyrate- but not 5-fluorouracil-induced apoptosis. p21cip1/waf1 overexpressing cells exhibited marked decrease of intestinal differentiation when assayed with intestinal alkaline phosphatase. Our findings suggest that introduction of p21cip1/waf1 gene into colon cancer cells may be useful for inhibiting cell growth but caution should be taken regarding the increased resistance to certain apoptosis-inducing agents and dysregulation of endogenous p21cip1/waf1-mediated differentiation process.

Pulmonary Mucosa-Associated Lymphoid Tissue Type Lymphoma With Increased Accumulation of Fluorine 18-Fluorodeoxyglucose on Positron Emission Tomography

Mucosa-associated lymphoid tissue (MALT) type lymphoma has generally been thought not to show increased fluorine 18-fluorodeoxyglucose (FDG) accumulation on positron emission tomography (PET), based on previous research. Only a limited numbers of articles have been published on this topic, however, involving a small number of cases. Although positive FDG PET results might be uncommon in this entity, a case of increased FDG accumulation in a case of MALT type lymphoma of the lung is presented.

Expression of Id proteins in human hepatocellular carcinoma: relevance to tumor dedifferentiation

Several studies reported that Id (Inhibitor of DNA binding or Differentiation) proteins, helix-loop-helix transcription factors, have important roles in differentiation, cell cycle and angiogenesis in various cells. However, the role of Id proteins in hepatocellular carcinoma (HCC) remains unclear. We examined the immunohistochemical expression of Id1, Id2 and Id3 proteins in 54 surgically resected HCCs with surrounding HCV or HBV-related chronic hepatitis (n=30) and liver cirrhosis (n=24). All non-cancerous livers exhibited immunoreactivity for Id proteins and the expression increased from chronic hepatitis to cirrhosis. In HCCs (n=45), well-differentiated tumors mostly exhibited strong or moderate immunostaining for all Id proteins, while proportion of the samples with weak or no expression increased with tumor dedifferentiation and frequently observed in poorly (66.7, 93.3 and 93.3% respectively for Id1, 2, 3) or undifferentiated (100% for all Ids) HCCs. Clinicopathological survey demonstrated a significant correlation between Id1, 2 and 3 expression and differentiation of carcinoma (p=0.0044, 0.0014 and 0.0014, respectively) although univariate analysis indicated that high expression of Id1 was significant predictive factor for longer disease-free survival of the patients (p=0.047). A similar tendency was also observed with Id2 and Id3. The present study demonstrate high expression of Id1, 2 and 3 in well-differentiated HCC and low expression in advanced dedifferentiated HCC, in contrast to its continuous expression during breast, prostate and colon carcinogenesis. These findings suggested that Id1, 2 and 3 might play a role in the early stages of hepatocarcinogenesis, but not in the development of advanced carcinoma, and might consequently be related to HCC dedifferentiation.

Effects of p21cip1/waf1 overexpression on growth, apoptosis and differentiation in human colon carcinoma cells

The cyclin-dependent kinase inhibitor p21cip1/waf1 negatively regulates the progression of cell cycle and the potential usefulness of p21cip1/waf1 gene is proposed in gene therapy. However, studies have demonstrated a protective role of p21cip1/waf1 against apoptosis and little is known about effects of ectopic expression of p21cip1/waf1 on differentiation of colon cancer cells. In the present study, we found diffuse p21cip1/waf1 expression in only a few clinical samples of colorectal cancer with wild-type p53 gene. To explore the role of p21cip1/waf1 in cell growth, apoptosis and differentiation, we constitutively overexpressed p21cip1/waf1 in HT29 colon carcinoma cells. Ectopic overexpression of p21cip1/waf1 was associated with inhibition of CDK2-associated kinase activity, indicating the functionality of the introduced p21cip1/waf1 gene. Overexpression of p21cip1/waf1 caused an appreciable growth inhibition in monolayer and soft agar cultures and it significantly reduced sodium butyrate- but not 5-fluorouracil-induced apoptosis. p21cip1/waf1 overexpressing cells exhibited marked decrease of intestinal differentiation when assayed with intestinal alkaline phosphatase. Our findings suggest that introduction of p21cip1/waf1 gene into colon cancer cells may be useful for inhibiting cell growth but caution should be taken regarding the increased resistance to certain apoptosis-inducing agents and dysregulation of endogenous p21cip1/waf1-mediated differentiation process.

Methylation and expression of p16INK4 tumor suppressor gene in primary colorectal cancer tissues

It is known that p16(INK4) tumor suppressor gene expression in colon cancer cells is repressed by methylation at the CpG island of promoter, but in vivo silencing of p16 gene is not fully understood. Some studies showed that primary colorectal cancer (CRC) tissues often overexpress the p16 protein, while others showed the high incidence of p16 methylation. The aim of this study was to clarify p16 gene regulation in vivo. We used real-time methylation-specific PCR (MSP) to examine density of p16 methylation, and immunohistochemistry, Western blot analysis to determine p16 protein expression. Methylation was detected in 5 CRC cell lines tested and 9 of 21 (42.9%) CRCs. Four of 5 CRC cell lines did not express p16 mRNA, but 6 of 9 CRCs did express p16 mRNA even with methylation. Real-time MSP showed that CRC tissues had a wide variety in methylation density (methylation index: 0.28-0.91) and that highly methylated CRC tissues displayed significantly lower p16 mRNA expression than those with no-methylation or low-methylation. Immunohistochemistry showed that the majority of CRCs (53 of 55: 96.4%) overexpressed the p16 protein. Low p16 expression was associated with lymph node metastasis (p=0.003) and large tumor size (p=0.048). Western blot in a subset of non-tumor and tumor samples showed a consistent overexpression of the p16 protein. These results showed that CRC tissues displayed variable methylation density, which may be characteristics of p16 gene methylation in vivo. Our data suggest that a low p16 expression due to methylation may contribute to tumor enlargement and expansion of CRC.

Partial contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway to antitumor effects of interferon-alpha/5-fluorouracil against Hepatocellular Carcinoma

PURPOSE

Our purpose was to explore the contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway to antitumor effects of IFNalpha and 5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

Susceptibility of HCC cell lines to TRAIL and/or 5-FU was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effects of 5-FU, IFNalpha, or both on the expression of TRAIL receptors (R1, R2, R3, and R4) on HCC cells or TRAIL in peripheral blood mononuclear cells (PBMC) were examined by flow cytometry. IFNalpha-induced cytotoxic effects of PBMC on HCC cell lines were examined by (51)Cr release assay. TRAIL expression in peripheral blood mononuclear cells and liver tissue from patients was examined by real-time reverse transcription-PCR or immunohistochemistry.

RESULTS

HLE and HepG2 were sensitive to TRAIL, but HuH7, PLC/PRF/5, and HLF were resistant. 5-FU had synergistic effect on TRAIL in HLF and additive effect in four other HCC cell lines. TRAIL receptors on HCC cells were up-regulated by 5-FU, and IFNalpha induced TRAIL on CD4(+) T cells, CD14(+) monocytes, and CD56(+) NK cells. Treatment of effector cells by IFNalpha and target HCC cells by 5-FU enhanced the cytotoxicity of CD14(+) monocytes and CD56(+) NK cells against HCC cells via a TRAIL-mediated pathway. TRAIL mRNA overexpression was noted in PBMC of HCC patients who clinically responded to IFNalpha/5-FU combination therapy, and TRAIL(+) mononuclear cells were found in cancer tissue of a responder.

CONCLUSION

Our results suggest that modulation of TRAIL/TRAIL receptor-mediated cytotoxic pathway might partially contribute to the anti-HCC effect of IFNalpha and 5-FU combination therapy.

Combination of IFN-alpha and 5-fluorouracil induces apoptosis through IFN-alpha/beta receptor in human hepatocellular carcinoma cells

PURPOSE

Several studies showed the effectiveness of combination therapy with IFN-alpha and 5-fluorouracil (5-FU) for advanced hepatocellular carcinoma. However, only little is known about the underlying mechanism of combination therapy. In the present study, we examined whether apoptosis through IFN-alpha/beta receptor (IFN-alpha/betaR) was associated with the effects of combination therapy.

EXPERIMENTAL DESIGN

HuH7, PLC/PRF/5, HLE, and HLF were treated with IFN- (500 units/mL), 5-FU (0.5 microg/mL), or their combination for 10 days. In addition, IFN-alpha/betaR gene transfer with combination therapy was done.

RESULTS

Ten-day treatment by combination therapy resulted in >80% cell growth inhibition. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling analysis showed synergistic effects for combination therapy on PLC/PRF/5, HLE, and HLF. Concordant results were obtained with DNA fragmentation. Moreover, there was an evidence showing that changes in the expression of Bcl-2 family lead to apoptosis. On the other hand, the expression of IFN-alpha/betaR and up-regulation of alpha-phospho-signal transducer and activator of transcription 1, IFN regulatory factor-1 by combination therapy were observed in all cell lines. Furthermore, IFN-alpha/type 2 IFN receptor long form-transfected HuH7 cells treated with combination therapy showed strong DNA fragmentation compared with nontransfected or transfected with IFN-alpha- and 5-FU-treated HuH7.

CONCLUSIONS

Our results showed that combination of IFN-alpha plus 5-FU strongly induced cell growth inhibition of human hepatocellular carcinoma cells and indicated that one of the direct mechanisms of combination therapy may in part be attributable to alterations in induction of apoptosis through IFN-alpha/betaR.

Expression of Id proteins in human hepatocellular carcinoma: relevance to tumor dedifferentiation

Several studies reported that Id (Inhibitor of DNA binding or Differentiation) proteins, helix-loop-helix transcription factors, have important roles in differentiation, cell cycle and angiogenesis in various cells. However, the role of Id proteins in hepatocellular carcinoma (HCC) remains unclear. We examined the immunohistochemical expression of Id1, Id2 and Id3 proteins in 54 surgically resected HCCs with surrounding HCV or HBV-related chronic hepatitis (n=30) and liver cirrhosis (n=24). All non-cancerous livers exhibited immunoreactivity for Id proteins and the expression increased from chronic hepatitis to cirrhosis. In HCCs (n=45), well-differentiated tumors mostly exhibited strong or moderate immunostaining for all Id proteins, while proportion of the samples with weak or no expression increased with tumor dedifferentiation and frequently observed in poorly (66.7, 93.3 and 93.3% respectively for Id1, 2, 3) or undifferentiated (100% for all Ids) HCCs. Clinicopathological survey demonstrated a significant correlation between Id1, 2 and 3 expression and differentiation of carcinoma (p=0.0044, 0.0014 and 0.0014, respectively) although univariate analysis indicated that high expression of Id1 was significant predictive factor for longer disease-free survival of the patients (p=0.047). A similar tendency was also observed with Id2 and Id3. The present study demonstrate high expression of Id1, 2 and 3 in well-differentiated HCC and low expression in advanced dedifferentiated HCC, in contrast to its continuous expression during breast, prostate and colon carcinogenesis. These findings suggested that Id1, 2 and 3 might play a role in the early stages of hepatocarcinogenesis, but not in the development of advanced carcinoma, and might consequently be related to HCC dedifferentiation.

Combination of IFN- and 5-Fluorouracil Induces Apoptosis through IFN-α/β Receptor in Human Hepatocellular Carcinoma Cells

Purpose: Several studies showed the effectiveness of combination therapy with IFN-α and 5-fluorouracil (5-FU) for advanced hepatocellular carcinoma. However, only little is known about the underlying mechanism of combination therapy. In the present study, we examined whether apoptosis through IFN-α/β receptor (IFN-α/βR) was associated with the effects of combination therapy.

Experimental Design: HuH7, PLC/PRF/5, HLE, and HLF were treated with IFN- (500 units/mL), 5-FU (0.5 μg/mL), or their combination for 10 days. In addition, IFN-α/βR gene transfer with combination therapy was done.

Results: Ten-day treatment by combination therapy resulted in &gt;80% cell growth inhibition. Terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling analysis showed synergistic effects for combination therapy on PLC/PRF/5, HLE, and HLF. Concordant results were obtained with DNA fragmentation. Moreover, there was an evidence showing that changes in the expression of Bcl-2 family lead to apoptosis. On the other hand, the expression of IFN-α/βR and up-regulation of α-phospho–signal transducer and activator of transcription 1, IFN regulatory factor-1 by combination therapy were observed in all cell lines. Furthermore, IFN-α/type 2 IFN receptor long form–transfected HuH7 cells treated with combination therapy showed strong DNA fragmentation compared with nontransfected or transfected with IFN-α- and 5-FU-treated HuH7.

Conclusions: Our results showed that combination of IFN-α plus 5-FU strongly induced cell growth inhibition of human hepatocellular carcinoma cells and indicated that oneof the direct mechanisms of combination therapy may in part be attributable to alterations in induction of apoptosis through IFN-α/βR.