EGFR gene amplification is related to adverse clinical outcomes in cervical squamous cell carcinoma, making the EGFR pathway a novel therapeutic target

Background:

The aim of this study was to investigate the patterns of epidermal growth factor receptor (EGFR) overexpression, EGFR gene amplification, and the presence of activating mutations in the tyrosine kinase domain of this gene in squamous cell carcinomas and adenocarcinomas/adenosquamous carcinomas of the uterine cervix.

Methods:

The EGFR expression, amplification, and mutation in cervical carcinomas were assessed by immunohistochemistry, fluorescence in situ hybridisation, and PCR–SSCP, respectively, and correlated with clinical data collected by a retrospective chart review. A functional assessment was performed by inactivating EGFR in cervical cancer cells with the potent inhibitor AG1478.

Results:

Immunohistochemical analysis revealed that 6 out of 59 (10.2%) cervical squamous cell carcinomas showed significant amplification of the EGFR locus, whereas none of the 52 adeno/adenosquamous cell carcinomas had detectable EGFR amplification (P<0.05). The EGFR amplification significantly correlated with shorter overall survival (P=0.001) in cervical squamous cell carcinomas. Multivariate analysis showed that EGFR gene amplification was an independent prognostic factor for overall survival (P=0.011). None of the squamous cell carcinomas (0%: 0 out of 32) had detectable oncogenic mutations in EGFR exons 18 through 21. The frequencies of KRAS and BRAF mutations were very low in both squamous and adeno/adenosquamous cell carcinomas. Sensitivity of cervical cancer cells to AG1478 depended on the presence of EGFR overexpression. AG1478-induced EGFR inactivation in cell lines with EGFR overexpression significantly suppressed tumour development and progression in a mouse xenograft model.

Conclusion:

Our data suggest that EGFR signalling is important in a subset of cervical squamous cell carcinomas and that anti-EGFR therapy may benefit patients who carry the 7p11.2 amplicon in their tumours.

α-Mangostin extracted from the pericarp of the mangosteen (Garcinia mangostana Linn) reduces tumor growth and lymph node metastasis in an immunocompetent xenograft model of metastatic mammary cancer carrying a p53 mutation

BACKGROUND

The mangosteen fruit has a long history of medicinal use in Chinese and Ayurvedic medicine. Recently, the compound α-mangostin, which is isolated from the pericarp of the fruit, was shown to induce cell death in various types of cancer cells in in vitro studies. This led us to investigate the antitumor growth and antimetastatic activities of α-mangostin in an immunocompetent xenograft model of mouse metastatic mammary cancer having a p53 mutation that induces a metastatic spectrum similar to that seen in human breast cancers.

METHODS

Mammary tumors, induced by inoculation of BALB/c mice syngeneic with metastatic BJMC3879luc2 cells, were subsequently treated with α-mangostin at 0, 10 and 20 mg/kg/day using mini-osmotic pumps and histopathologically examined. To investigate the mechanisms of antitumor ability by α-mangostin, in vitro studies were also conducted.

RESULTS

Not only were in vivo survival rates significantly higher in the 20 mg/kg/day α-mangostin group versus controls, but both tumor volume and the multiplicity of lymph node metastases were significantly suppressed. Apoptotic levels were significantly increased in the mammary tumors of mice receiving 20 mg/kg/day and were associated with increased expression of active caspase-3 and -9. Other significant effects noted at this dose level were decreased microvessel density and lower numbers of dilated lymphatic vessels containing intraluminal tumor cells in mammary carcinoma tissues. In vitro, α-mangostin induced mitochondria-mediated apoptosis and G1-phase arrest and S-phase suppression in the cell cycle. Since activation by Akt phosphorylation plays a central role in a variety of oncogenic processes, including cell proliferation, anti-apoptotic cell death, angiogenesis and metastasis, we also investigated alterations in Akt phosphorylation induced by α-mangostin treatment both in vitro and in vivo. Quantitative analysis and immunohistochemistry showed that α-mangostin significantly decreased the levels of phospho-Akt-threonine 308 (Thr308), but not serine 473 (Ser473), in both mammary carcinoma cell cultures and mammary carcinoma tissues in vivo.

CONCLUSIONS

Since lymph node involvement is the most important prognostic factor in breast cancer patients, the antimetastatic activity of α-mangostin as detected in mammary cancers carrying a p53 mutation in the present study may have specific clinical applications. In addition, α-mangostin may have chemopreventive benefits and/or prove useful as an adjuvant therapy, or as a complementary alternative medicine in the treatment of breast cancer.

Sunitinib suppresses tumor growth and metastases in a highly metastatic mouse mammary cancer model

BACKGROUND

Sunitinib is an inhibitor that blocks tyrosine phosphorylation (p-Tyr) of receptors including vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor. Sunitinib suppresses angiogenesis and cell proliferation and is an effective treatment for renal cell carcinoma and gastrointestinal stromal tumors. In the present study, we examined the antitumor and antimetastatic activities of sunitinib in mouse metastatic mammary cancer.

MATERIALS AND METHODS

Mammary tumors induced by inoculation of BJMC3879 cells into mice were treated with sunitinib using mini-osmotic pumps. At 1 week and 7 weeks after initiation of drug administration, cancer tissue was removed and carried out histopathological and immunohistochemical examination.

RESULTS

Tumor growth, as well as metastasis to the lungs and other organs, was significantly inhibited in sunitinib-treated mice. Cell death areas in mammary carcinomas were much larger in the sunitinib-treated groups than in the control group. In addition, sunitinib induced necrotic cell death rather than apoptosis. Although microvessel density was significantly lower in the sunitinib-treated mammary tumors, numbers of metastases to lymph nodes and the number of lymphatic vessels in the mammary tumors were not significantly different among groups. Cell proliferation, as assessed by BrdU-labeling indices, was significantly lower in mammary carcinomas of sunitinib-treated mice. The amounts of p-VEGFR-2 and p-Tyr, as determined by immunohistochemistry, were greatly reduced in sunitinib-treated mice.

CONCLUSION

In a mouse model of mammary cancer, sunitinib inhibited tumor growth and metastasis (with the exception of lymph node metastasis), angiogenesis, and cell proliferation possibly due to reduced levels of p-VEGFR-2 and p-Tyr.

Expression of the GABAA receptor/chloride channel in murine spermatogenic cells

Previous studies from our laboratory have demonstrated that γ-aminobutyric acid (GABA) and GABAB receptor subunits are expressed within the acrosome of spermatids during spermiogenesis. Furthermore, our previous study with the glutamate decarboxylase (GAD) 67-GFP knock-in mouse demonstrated that GFP-positive cells were localized to the epithelium of the caput of epididymis. In the present study, we detected GABAA subunits, including α1, α5, β1-3 and γ3, and both isoforms of GAD, GAD65 and GAD67, in mouse spermatogenic cells using RT-PCR. The expression of these proteins was subsequently confirmed by western blot analysis. Immunohistochemistry also revealed that GABA, GAD65, and α5, β1 and γ3 subunits of the GABAA receptor were localized in the membrane of spermatogenic cells, including spermatocytes and spermatids. The whole-cell patch-clamp analysis demonstrated that GABA application induced an inward chloride current in some of the large and round spermatogenic cells. Our findings show that spermatogenic cells have a GABA producing system by themselves, and that GABA may function via the ionotropic GABAA receptor. This data suggests that the GABAergic system may play important roles in the male reproductive system.

Anomalous branching pattern of external carotid artery: Clinical relevance to cervicofacial surgery

Anomalous branching pattern of the left external carotid artery (ECA) was detected in an old man. The ECA branched into high submental artery and large transverse facial artery ending as angular artery compensating for concurrent agenesis of ipsilateral facial artery. The lingual artery gave direct branch to the submandibular gland, whereas the superior thyroid artery arose directly from common carotid artery with high bifurcation level. This unreported branching pattern of the ECA may have important clinical relevance to cervicofacial surgery.

The cellular expression of GABA(A) receptor alpha1 subunit during spermatogenesis in the mouse testis

GABA(A) receptors are pentamers in structure and are mainly composed of alpha, beta and gamma subunits. These receptors are known to function as chloride channels. We observed alpha5, beta1 and gamma3 subunit immunoreactivity in the mouse testes, specifically in the cytoplasm surrounding the nucleus in the spermatocytes and spermatids. In the current study, alpha1 subunit immunoreactivity was located in the nucleus of spermatogonia, spermatocytes and round spermatids. Immunoelectron microscopy revealed that the alpha1 subunit was localized within the nucleus of pachytene and diplotene spermatocytes in the area of condensed chromatin rather than extended chromatin. Protein sequence analysis revealed that the alpha1 subunit included DM DNA binding domains that were related to transcription factors involved in testicular differentiation in adult mice. These findings suggest that the alpha1 subunit may undertake a gene transcription function during the maturation of germ cells. a1 immunoreactivity was also detected within the mitochondria of spermatocytes and in the acrosome of round and elongated spermatids. Although the precise physiological role of the GABA(A) receptor alpha1 subunit in mitochondria remains unknown, we hypothesize that its function in the acrosome may be related to the acrosome reaction during fertilization or during spermatogenesis.

The endogenous soluble VEGF receptor-2 isoform suppresses lymph node metastasis in a mouse immunocompetent mammary cancer model

BACKGROUND

Cancer metastasis contributes significantly to cancer mortality and is facilitated by lymphangiogenesis and angiogenesis. A new splicing variant, endogenous soluble vascular endothelial growth factor receptor-2 (esVEGFR-2) that we recently identified is an endogenous selective inhibitor of lymphangiogenesis. To evaluate the antimetastatic potential of esVEGFR-2, gene therapy with vector expressing esVEGFR-2 (pesVEGFR-2) or endostatin (pEndo) as a positive control was conducted on murine metastatic mammary cancer.

METHODS

Syngeneic inoculated metastatic mammary cancers received direct intratumoral injection of pesVEGFR-2, pEndo or pVec as control, once a week for six weeks. In vivo gene electrotransfer was performed on the tumors after each injection.

RESULTS

Deaths from metastasis were much lower in the pesVEGFR-2 and pEndo groups than in those of the pVec. Tumor volume was significantly lower in the pesVEGFR-2 and the pEndo groups throughout the study. Multiplicity of lymph node and lung metastatic nodules was significantly suppressed in the pesVEGFR-2 and pEndo groups. Moreover, the total number of overall metastasis including the other organs was also decreased in these groups. However, pesVEGFR-2 was not able to decrease the number of lungs, ovaries, kidneys and adrenals with metastasis as counted by unilateral or bilateral metastasis. The number of CD34+/Lyve-1⁻ blood microvessels was significantly decreased in the pEndo group, while the number of CD34⁻/Lyve-1+ lymphatic vessels was significantly decreased in the pesVEGFR-2 and pEndo groups. In addition, a significant reduction in the number of dilated lymphatic vessels containing intraluminal cancer cells was observed in the pesVEGFR-2 and pEndo groups. Levels of apoptosis were significantly increased in the pEndo group, whereas the rates of cell proliferation were significantly decreased in the pesVEGFR-2 and pEndo groups.

CONCLUSIONS

Our data demonstrate that esVEGFR-2 can inhibit mainly lymph node metastasis. The antimetastatic activity of esVEGFR-2 may be of high clinical significance in the treatment of metastatic breast cancer because lymph node involvement is a most important prognostic factor in cancer patients.

Raloxifene inhibits tumor growth and lymph node metastasis in a xenograft model of metastatic mammary cancer

BACKGROUND

The effects of raloxifene, a novel selective estrogen receptor modulator, were studied in a mouse metastatic mammary cancer model expressing cytoplasmic ERα.

METHODS

Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879luc2 cells, were subsequently treated with raloxifene at 0, 18 and 27 mg/kg/day using mini-osmotic pumps.

RESULTS

In vitro study demonstrated that the ERα in BJMC3879luc2 cells was smaller (between 50 and 64 kDa) than the normal-sized ERα (66 kDa) and showed cytoplasmic localization. A statistically significant but weak estradiol response was observed in this cell line. When BJMC3879luc2 tumors were implanted into mice, the ERα mRNA levels were significantly higher in females than in males. In vitro studies showed that raloxifene induced mitochondria-mediated apoptosis and cell-cycle arrest in the G1-phase and a decrease in the cell population in the S-phase. In animal experiments, tumor volumes were significantly suppressed in the raloxifene-treated groups. The multiplicity of lymph node metastasis was significantly decreased in the 27 mg/kg group. Levels of apoptosis were significantly increased in the raloxifene-treated groups, whereas the levels of DNA synthesis were significantly decreased in these groups. No differences in microvessel density in tumors were observed between the control and raloxifene-treated groups. The numbers of dilated lymphatic vessels containing intraluminal tumor cells were significantly reduced in mammary tumors in the raloxifene-treated groups. The levels of ERα mRNA in mammary tumors tended to be decreased in the raloxifene-treated groups.

CONCLUSION

These results suggest that the antimetastatic activity of raloxifene in mammary cancer expressing cytoplasmic ERα may be a crucial finding with clinical applications and that raloxifene may be useful as an adjuvant therapy and for the chemoprevention of breast cancer development.

Inguinal lymph node metastases are recognized with high frequency in rectal adenocarcinoma invading the dentate line. The histological features at the invasive front may predict inguinal lymph node metastasis

AIM

Inguinal lymph node (ILN) metastasis occurs with high frequency in some of the patients with lower rectal cancer. The aim of this study was to identify risk factors for ILN metastasis in patients with low rectal adenocarcinoma.

METHOD

We retrospectively analysed 156 patients with lower rectal adenocarcinoma who underwent radical resection (R0) at a single institution.

RESULTS

Twenty-five (16%) patients had a tumour that invaded the dentate line, seven of whom had ILN metastasis. Invasion of the dentate line was significantly associated with a high rate of ILN metastasis, worse prognosis and local recurrence than with a tumour not invading the dentate line (P = 0.03). A Cox proportional hazard regression analysis revealed the histological characteristics at the invading front (Hif) also to be a risk factor for ILN metastasis.

CONCLUSION

Tumours which invade the dentate line have a high rate of ILN metastases and worse cancer specific end-points. The presence of poorly differentiated or mucinous adenocarcinoma components is an indication for bilateral groin irradiation.

Correlation between particle multiplicity and location on virion RNA of the assembly initiation site for viruses of the tobacco mosaic virus group

The initiation site for reconstitution on genome RNA was determined by electron microscopic serology for a watermelon strain of cucumber green mottle mosaic virus (CGMMV-W), which is chemically and serologically related to tobacco mosaic virus (TMV). The initiation site was located at the same position as that of the cowpea strain, a virus that produces short rods of encapsidated subgenomic messenger RNA for the coat protein (a two-component TMV), being about 320 nucleotides away from the 3' terminus, and hence within the coat protein cistron. Although CGMMV-W was until now believed to be a single-component TMV, the location of the initiation site indicated the presence of short rods containing coat protein messenger RNA in CGMMV-W-infected tissue, as in the case for the cowpea strain. We found such short rods in CGMMV-W-infected tissue. The results confirmed our previous hypothesis that the site of the initiation region for reconstitution determines the rod multiplicity of TMV. The finding of the second two-component TMV, CGMMV, indicates that the cowpea strain of TMV is not unique in being a two-component virus and that the location of the assembly initiation site on the genome RNA can be a criterion for grouping of viruses.

An immunocompetent murine model of metastatic mammary cancer accessible to bioluminescence imaging

BACKGROUND

Many areas of research, including gene and pharmacological therapeutics, would benefit from longitudinal in vivo monitoring methodologies. To investigate the feasibility of one such methodology, we developed a murine mammary cancer model amenable to sequential bioluminescent imaging of tumor growth and metastasis in living animals.

MATERIALS AND METHODS

Metastatic mouse mammary carcinoma BJMC3879 cells were transfected to stably express firefly luciferase and inoculated into immunocompetent female BALB/c mice.

RESULTS

Sequential analysis using bioluminescent imaging showed increasing photon counts correlated to expanding mammary tumor volumes; in addition, strong signals from axillary, mandibular, femoral, thoracic and abdominal regions in mice were histopathologically determined to be due to metastases, the majority of which occurred in lymph nodes and lungs.

CONCLUSION

The bioluminescent mouse mammary cancer model we established provides a method for quantifiable longitudinal in vivo imaging that can be used in gene and pharmacological therapy applications.

Phagocytosis mechanism of apoptotic granulosa cells regulated by milk-fat globule-EGF factor 8

In the process of ovary sexual maturation, most immature ovarian follicles degrade into atretic follicles accompanied by apoptosis in granulosa cells. Macrophages can recognize apoptotic cells through specific binding with phosphatidylserine (PS), exposed on the surface of apoptotic cells, which is mediated by milk-fat globule-EGF factor 8 (MFG-E8). In the present research, we examined the involvement of the MFG-E8-dependent phagocytosis system in the atretic follicles of developing mouse ovaries. The number of atretic follicles and DNA-fragmented granulosa cells significantly increased in B6C3F1 mice during 2 to 6 weeks. Chromatin-condensed granulosa cells were engulfed by macrophages, which existed in the stroma or atretic follicles, or by neighboring normal granulosa cells. MFG-E8 mRNA increased in ovaries during 2 to 6 weeks, and immunoreactivity of MFG-E8 was detected at the surface of apoptotic cells existing around the antrum. Immunoelectron microscopic study revealed MFG-E8-positive signals on the membrane of apoptotic cells near macrophages, but apoptotic cells engulfed by neighboring granulosa cells showed few signals. Anti-Fas antibody elevated the annexin-V-positive reaction in isolated granulosa cells from 3-week-old mouse ovaries. MFG-E8 seems to act on the phagocytosis of apoptotic granulosa cells via macrophages and contribute to the regression process of atretic follicles.

Expression and distribution of GABAergic system in rat knee joint synovial membrane

The GABAergic system, found in the adult mammalian brain and composed of gamma-aminobutyric acid (GABA), GABA synthesizing enzyme glutamate decarboxylase (GAD) and GABA receptors, is also located in many peripheral nonneuronal tissues. Studies suggest that synovial membranes possess GABA, and that GABA participates in the control of the inflammatory response in rheumatoid arthritis (RA). However, no studies on the GABAergic system in synovial membranes have been done so far. Therefore, expression and distribution of the GABAergic system in the synovial membrane of the normal rat knee joint were investigated by reverse transcription-polymerase chain reaction (RT-PCR) analyses and immunohistochemistry. Results of RT-PCR analysis showed that mRNA encoding the GAD65 and GABAB receptor subunits necessary for the assembly of functional receptors, R1 and R2, are expressed in the synovial membrane. GAD and GABAB receptor subunits were localized in macrophage-like A cells of the synovial membrane. Macrophage-like A cells of the synovial membrane have a GABA production system and GABAB receptors, and GABA seems to play functional roles in the synovial membrane.

Panaxanthone isolated from pericarp of Garcinia mangostana L. suppresses tumor growth and metastasis of a mouse model of mammary cancer

BACKGROUND

The antitumor growth and antimetastatic activity of panaxanthone (approximately 80% alpha-mangostin and 20% gamma-mangostin) were studied in a mouse metastatic mammary cancer model that produces a metastatic spectrum similar to that seen in human breast cancer.

MATERIALS AND METHODS

Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were subsequently treated with panaxanthone at 0, 2,500, or 5,000 ppm in their diet. In vitro studies were also conducted to evaluate the effects of alpha-mangostin, the main component of panaxanthone, on BJMC3879 cells.

RESULTS

In the in vivo study, tumor volumes were significantly suppressed in mice treated with 2,500 and 5,000 ppm panaxanthone in their diet. The multiplicity of lung metastasis was significantly lower in the 5,000 ppm group. Lymph node metastasis also tended to decrease in the 5,000 ppm group but not significantly. The antitumor effects of panaxanthone were associated with elevation of apoptotic cell death, antiproliferation (inhibition of PCNA) and antiangiogenesis (inhibition of microvessel density). The in vitro study demonstrated that alpha-mangostin induced apoptosis, as evidenced by increased numbers of TUNEL-positive cells, elevated activities of caspases and a decrease in mitochondrial membrane potential, cell cycle arrest in the G(1)-phase and decreases in the cell population in the S- and G(2)/M-phases.

CONCLUSION

These results suggest that the observed antimetastatic activity of panaxanthone may be of clinical significance as adjuvant therapy in metastatic human breast cancer, and may also be useful as a chemopreventative of breast cancer development.

Riluzole induces apoptotic cell death in human prostate cancer cells via endoplasmic reticulum stress

BACKGROUND

Ion channel modulators have been previously associated with cell proliferation and cell death in human cancer cell lines.

MATERIALS AND METHODS

The effects of riluzole, an ion channel modulator, on cell proliferation, apoptosis and the apoptotic pathway in the LNCaP and C4-2 prostate cancer cell lines were investigated.

RESULTS

Riluzole inhibited DNA synthesis and increased apoptotic cells in both cell lines. The activities of caspase-3, -8 and -9 were significantly increased, and caspase inhibitors for caspase-3, -8 and -9 significantly rescued the cell viability of both carcinoma cell lines treated with riluzole. However, a change in mitochondrial membrane potential, release of cytochrome c and cleavage of Bid were not observed in the riluzole-treated cells. Riluzole significantly induced elevation of caspase-4 activity, fluorescence indicating cytosolic calcium, and morphological changes in endoplasmic reticulum (ER) as observed by transmission electron microscopy.

CONCLUSION

Riluzole induces inhibition of DNA synthesis and apoptotic cell death via ER stress in both the LNCaP and C4-2 prostate cancer cell lines.

Proliferative effects of gamma-aminobutyric acid on the gastric cancer cell line are associated with extracellular signal-regulated kinase 1/2 activation

BACKGROUND AND AIM

Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the adult mammalian brain. However, GABA is found not only in peripheral neuronal tissue, but also in many peripheral non-neuronal tissues, and is thought to have important physiological functions in addition to neurotransmission. We previously reported that GABA participates in chondrocyte proliferation. In the present study, we investigated the effects of GABA on the proliferation of a gastric cancer cell line, KATO III.

METHODS

Reverse transcription polymerase chain reaction and immunohistochemical analyses were performed to examine the expression of the GABA synthesis enzyme, glutamate decarboxylase (GAD), and that of the GABA(A) and GABA(B) receptor subunits. The production of GABA was confirmed by immunohistochemistry. The proliferative effect of GABA on KATO III cells was analyzed by bromodeoxyuridine incorporation assay, and the activation status of mitogen-activated protein (MAP) kinases (extracellular signal-regulated kinase [ERK]-1/2, Jun-N-terminal kinase, and p38) and the expression of cyclin D1 were analyzed by western blotting.

RESULTS

KATO III cells expressed GAD and GABA. More than five GABA(A) receptor subunits, including the pi subunit, were expressed in KATO III cells; however, GABA(B) receptor subunits were not seen. The addition of GABA to the medium promoted KATO III proliferation, and maximum proliferative effects were observed in the presence of 10 or 1 microM GABA. The addition of 1 microM GABA predominantly activated ERK-1/2 among the three MAP kinases in addition to increasing cyclin D1 expression.

CONCLUSION

GABA is able to promote KATO III cell proliferation in an autocrine or a paracrine fashion through GABA(A) receptors followed by MAP kinase activation.

Raloxifene, a selective estrogen receptor modulator, induces mitochondria-mediated apoptosis in human endometrial carcinoma cells

Raloxifene is a nonsteroidal benzothiophene that has also been classified as a selective estrogen receptor modulator (SERM) on the basis of studies in which it produced both estrogen-agonistic effects on bone and lipid metabolism and estrogen-antagonistic effects on uterine endometrium and breast tissue. We investigated apoptotic cell death and the apoptotic pathway in human endometrial carcinoma cells (Ishikawa cells) expressing estrogen receptor treated with raloxifene. Cell viability was significantly decreased in Ishikawa cells treated with raloxifene at 20 microM and higher levels. Raloxifene at 20 microM induced 54% inhibition of cell viability after 48 h treatment. Apoptotic parameters were analyzed for determination of apoptotic pathway in Ishikawa cells treated with 20 microM or 40 microM raloxifene for 48 h. The numbers of apoptotic cells were significantly increased in cells treated with raloxifene as compared with control cells. Activities of caspase-3,-8, and-9 were significantly elevated in Ishikawa cells treated with raloxifene. A significant decrease in mitochondrial membrane potential was observed in this treatment. In addition, the levels of cytosolic cytochrome c were significantly elevated in raloxifene-treated cells. Expression of Bid was detected in both control and raloxifene-treated cells, but Bid cleavage was not observed. In caspase inhibitor experiments, cell viability was significantly increased by the caspase-9 inhibitor z-LEHD-fmk and by the caspase-3 inhibitor z-DEVD-fmk. However, cell viability was unaffected by addition of the caspase-8 inhibitor z-IETD-fmk. Thus, raloxifene induced mitochondria-mediated apoptosis in endometrial cancer cells but not via the Bid-mitochondria pathway. It is possibly that raloxifene may be useful as an adjuvant to current chemotherapies for endometrial cancer and possibly is useful as a chemopreventive agent.

Marked regression of liver metastasis by combined therapy of ultrasound-mediated NF kappaB-decoy transfer and transportal injection of paclitaxel, in mouse

Nuclear factor-kappaB (NF kappaB) plays a pivotal role in cancer progression. In this study, we developed a decoy cis-element oligo-deoxyribonucleic acid against NF kappaB-binding site (NF kappaB-decoy), which effectively inhibits NF kappaB activity, and tested the effect of combined therapy comprising local transfection of NF kappaB-decoy into the liver and transportal injection of paclitaxel on cancer growth and metastasis using an orthotopic murine model of colon cancer liver metastasis. For NF kappaB-decoy transfection, we employed a novel approach using ultrasound exposure with an echocardiographic contrast agent, Optison. We examined the influence of NF kappaB-decoy transfer on susceptibility to paclitaxel in cancer cells and the mechanism involved using several in vitro analysis systems. We then studied the in vivo effect of combined NF kappaB-decoy transfer and paclitaxel in preventing cancer progression using a murine model of liver metastasis created by splenic injection of a human colon cancer cell line, HT29. In vitro experiments, including MTT-assay, fluorescence-activated cell sorter and cDNA array analysis, revealed that NF kappaB-decoy transfer significantly increased the susceptibility of cancer cells to paclitaxel, and that decreased expression of anti-apoptotic genes along with increased expression of genes relevant to the apoptosis-promotor may be involved. In vivo experiments showed that local transfection of NF kappaB-decoy into the liver followed by portal injection of paclitaxel effectively induced cancer cell apoptosis in the liver metastasis, and significantly prolonged animal survival compared to controls, without notable side effects. In conclusion, a combination of local NF kappaB-decoy transfer into the liver and transportal injection of paclitaxel may be a safe and effective new therapy for liver metastasis.

Easy stable transfection of a human cancer cell line by electrogene transfer with an Epstein–Barr virus-based plasmid vector

We report an easy and stable transfection technique using electrogene transfer with a nonviral Epstein-Barr (EB) virus-based vector. To achieve stable transfection of human breast cancer cells, we conducted electrogene transfer of an EB virus-based plasmid vector (reduced size of oriP) containing the enhanced green fluorescence protein (eGFP) gene. Because the EB virus-based vector exhibits high transfer efficiency and strong persistent transgene expression as a result of autonomous replication in human cells, and as Nucleofector electrogene transfer can achieve highly efficient gene transfection, this method is particularly suitable for generation of stably transfected cell lines.

Vaticanol C, a novel resveratrol tetramer, reduces lymph node and lung metastases of mouse mammary carcinoma carrying p53 mutation

PURPOSE

The effects of vaticanol C (Vat-C), a novel resveratrol tetramer, were studied in a mouse metastatic mammary cancer model carrying mutations in p53 that produce a metastatic spectrum similar to that seen in human breast cancers.

METHODS

Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879 cells, were subsequently treated with Vat-C at 0, 100 and 200 ppm in their diet.

RESULTS

The in vitro study demonstrated that Vat-C induced apoptosis, as inferred by morphological changes, nucleosomal DNA fragmentation and elevated activities of caspases. Although tumor volumes were not apparently suppressed in mice treated with Vat-C, the multiplicity of lymph node metastasis was significantly decreased in the 200-ppm group. Furthermore, the multiplicity of lung metastasis was also significantly lower in the 200-ppm group. In any category of organ metastasis, the number of organs with metastasis tended to be lower in the 200-ppm group, but these findings were not statistically significant. The levels of apoptosis were significantly higher in the 200-ppm group, but DNA synthesis only a tended to be lower in this group. Microvessel density in tumors also tended to be lower in the Vat-C-treated groups. Moreover, the numbers of lymphatic vessels having intraluminal tumor cells was significantly lower in mammary tumors of mice given 100 and 200-ppm Vat-C, indicating a reduction in migrating tumor cells into the lymphatic vessels of tumor tissue.

CONCLUSIONS

These results suggest that the observed antimetastatic activity of Vat-C may be of clinical significance as an adjuvant therapy in metastatic human breast cancer having p53 mutations, and may also be useful as a chemopreventative of breast cancer development.

Massive apoptotic cell death of human glioma cells via a mitochondrial pathway following 5-aminolevulinic acid-mediated photodynamic therapy

The basic mechanism of cell death induced by 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT) (ALA-PDT) in glioma cells has not been fully elucidated. In this study, the details of the cell death mechanism induced by ALA-PDT were investigated in three human glioma cell lines (U251MG, U87MG, and U118MG) in vitro. To evaluate the manner of accumulation of protoporphyrin IX (PpIX), intracellular PpIX contents were measured by flow cytometry after incubation with 5-ALA. To analyze the mechanism of cell death, U251MG cells were assayed by the terminal deoxynucleotidyl transferase-mediated dUTP-FITC nick end-labeling (TUNEL) method, and the caspase activity was measured after ALA-PDT. Furthermore, the mitochondrial membrane potential (MMP) and the release of mitochondrial cytochrome c were determined. PpIX fluorescence reached a plateau 4 h after exposure to 5-ALA. The proportion of dead cells increased with increases in the dosage of light. These cells were confirmed by TUNEL staining to be apoptotic. Increases in the activity of both caspase-3 and -9, a decrease in MMP, and a marked increase in cytochrome c in the cytosolic fraction were found after cells were subjected to PDT. These results indicate that a dysfunction of MMP is followed by mitochondrial cytochrome c release, which triggers apoptosis through a mitochondrial pathway. ALA-PDT induces massive apoptosis due to the direct activation of a mitochondrial pathway, which is resistant to many anti-apoptotic processes, in human glioma cells. This finding implies that ALA-PDT is a promising therapy for the treatment of apoptosis-reluctant tumors such as malignant gliomas.

FTY720 induced Bcl-associated and Fas-independent apoptosis in human renal cancer cells in vitro and significantly reduced in vivo tumor growth in mouse xenograft

BACKGROUND

A unique immunosuppressant, FTY720, selectively induces apoptosis in activated lymphocytes, but not in other hematopoietic cells. The potential that this unique mechanism could provide anticancer potential by inducing apoptosis in the human renal cancer cell line, ACHN, which is resistant to cisplatin, and its molecular pathway was investigated.

MATERIALS AND METHODS

The difference in drug susceptibility to FTY720 between cancer cells and non-cancer cells was examined by MTT assay and flow cytometry. Apoptosis assay, including TUNEL staining, electron microscopy and DNA electrophoresis, was performed and the molecular pathway of FTY720 was evaluated by real time RT-PCR and Western blot. The in vivo effect of FTY720 was evaluated using a murine zenograft model.

RESULTS

The susceptibility to FTY720 was significantly higher in ACHN cancer cells than in normal renal tubular cells (HK-2) at a concentration of less than 30 microM, while the susceptibility to cisplatin was even higher in HK-2 than in ACHN. Cancer cells treated with FTY720 showed findings typical of apoptosis with highly condensed nuclear chromatin and fragmented nuclei. The molecular analysis revealed that FTY720-induced apoptosis was mediated by a Fas-independent, Bcl-associated signal transduction pathway, and that inhibition of extracellular signal-regulated kinase (ERK) activity was involved in its underlying mechanism of action. FTY720 treatment significantly prevented in vivo tumor growth without any severe adverse reactions, while cisplatin treatment did not inhibit tumor growth despite exhibiting severe side-effects.

CONCLUSION

FTY720 may be a promising candidate for a new anticancer therapy of renal cancer.

Electrogene therapy using endostatin, with or without suicide gene therapy, suppresses murine mammary tumor growth and metastasis

Syngeneic inoculated metastatic mammary cancers received direct intratumoral injection of a plasmid vector containing either endostatin (pEndo) with or without a suicide gene (pHSVtk), pHSVtk alone or control vector once a week for 8 weeks. We applied electrogene transfer to the tumors after each injection and administered ganciclovir (GCV) to pHSVtk-transfected mice using an osmotic minipump. Anticancer efficacy was monitored using a variety of parameters, namely tumor volume, intratumoral microvessel density and DNA synthesis, number of mice with metastasis, and number of sites of metastasis per mouse. Tumor volume was significantly lower in all therapeutic groups, with the most effective growth suppression in the pEndo+pHSVtk/GCV group. Lymph node metastasis was significantly less frequent in all therapeutic groups, whereas the multiplicity of lung metastases was significantly lower only in the pEndo and pEndo+pHSVtk/GCV groups. All therapeutic groups showed significantly lower intratumor microvessel density and DNA synthesis. The pEndo and pEndo+pHSVtk/GCV groups also showed a significant reduction in the numbers of dilated lymphatic vessels containing intralumenal tumor cells. Our data suggest that endostatin electrogene therapy alone or in combination with pHSVtk/GCV suicide gene therapy is more beneficial than suicide gene therapy alone. The observed antimetastatic activity of endostatin may be of high clinical significance in the treatment of metastatic breast cancer.

COX-2 inhibitor celecoxib suppresses tumor growth and lung metastasis of a murine mammary cancer

BACKGROUND

The antitumor growth and antimetastatic actions of celecoxib [a selective cyclooxygenase-2 (COX-2) inhibitor] were investigated in a metastatic murine mammary cancer model.

MATERIALS AND METHODS

Mice bearing mammary tumors, developed after inoculation of syngeneic BALBIc mice with a mammary carcinoma cell line carrying a p53 mutation, were treated with celecoxib at 0, 7.5 and 15 mg/kg five times a week for seven weeks.

RESULTS

Tumor volumes were significantly reduced in association with an increase in apoptosis and a decrease in DNA synthesis in tumor tissues. In vitro studies demonstrated a significant increase in the number of cells undergoing apoptosis, with significantly elevated activities of caspase-3 and caspase-9, but not caspase-8, and a dose-dependent decrease in mitochondrial membrane potential, indicating the mitochondrial pathway of apoptosis. In addition, treatment with celecoxib showed cell cycle arrest in the G -phase and decreased cell population in the S- and G2/M-phases. Furthermore, tumor microvessel formation and mRNA levels for VEGF-A and COX-2 were markedly decreased.

CONCLUSION

Celecoxib may be useful as an adjuvant therapy for breast cancer containing p53 mutations due to its ability to both induce p53-independent mitochondria-mediated apoptosis and exert anti-angiogenic potential.

Effect of danazol on NK cells and cytokines in the mouse uterus

Danazol, which has been used as a medicine for endometriosis, has a valid effect in pretreatment of patients receiving in vitro fertilization and embryo transfer, although its reproductive mechanism remains unclear. BALB/c mice were subcutaneously injected with danazol for 2 weeks. Blood and uteri were collected and cytokines were assayed. Following danazol treatment, an increase in pregnancy ratio was evident that was accompanied by up-regulation in serum macrophage-colony stimulating factor (M-CSF). RT-PCR analysis revealed that expression of M-CSF and Ly49, a phenotypic marker of natural killer (NK) cells, was up-regulated in the uteri of the danazol-treated mice. In immunohistochemical analysis, M-CSF and Ly49, together with alpha5 integrin, were clearly detected in the endometrium of the danazol-treated mice with very similar pattern of localization. These results suggest that danazol has an effect to promote pregnancy that induces recruitment of NK cells and a concomitant increase in the expression of M-CSF and alpha5 integrin in the uterus.

Mechanism of Inflammation in Murine Eosinophilic Myocarditis Produced by Adoptive Transfer with Ovalbumin Challenge

BACKGROUND

Interleukin (IL)-5, RANTES and CC chemokine receptor 3 (CCR3) are essential for induction of eosinophil recruitment in organs, but the precise pathogenesis of eosinophilic myocarditis is still unclear. We investigated the relationships between these cytokines and receptors in the development of inflammation in murine myocarditis produced by adoptive transfer, with reference to eosinophil infiltration and signal transduction.

METHODS

The splenocytes from male donor DBA/2 mice were separated after ovalbumin (OVA) sensitization. These cells had a CD4/CD8 ratio of approximately 3.0. Cells (2.0 x 10(7)) were individually transfused to recipient adoptive male DBA/2 mice, and OVA challenge was performed serially. The heart and spleen of the recipient were analyzed to determine the kinetics of IL-5, RANTES, CCR3 and eosinophil production with simultaneous determination of Janus kinase 3 (JAK3) mRNA.

RESULTS

Approximately 85% of recipient mice developed myocarditis; 35% had recognizable cell infiltration in the left ventricular endocardium, an effect which was absent in control mice. Eosinophilic myocarditis was usually associated with animals having several degenerative changes in myocardial cells, and IL-5, RANTES and CCR3 expressions were usually present in these eosinophils (p < 0.05). CCR3 and JAK3 mRNAs were detected in the spleens and hearts of recipient animals providing histological evidence for kinetics related to eosinophil infiltration.

CONCLUSION

The murine model of adoptive transferred myocarditis is suitable for studying the mechanism of eosinophilic myocarditis. A unique pathogenesis of this disorder may be controlled by the synergism of CD4 dominancy in the donor and JAK-STAT signaling in the recipient, which may cause recruitment of eosinophils into heart lesions.

Novel therapeutic strategy for stroke in rats by bone marrow stromal cells and ex vivo HGF gene transfer with HSV-1 vector

Occlusive cerebrovascular disease leads to brain ischemia that causes neurological deficits. Here we introduce a new strategy combining mesenchymal stromal cells (MSCs) and ex vivo hepatocyte growth factor (HGF) gene transferring with a multimutated herpes simplex virus type-1 vector in a rat transient middle cerebral artery occlusion (MCAO) model. Gene-transferred MSCs were intracerebrally transplanted into the rats' ischemic brains at 2 h (superacute) or 24 h (acute) after MCAO. Behavioral tests showed significant improvement of neurological deficits in the HGF-transferred MSCs (MSC-HGF)-treated group compared with the phosphate-buffered saline (PBS)-treated and MSCs-only-treated group. The significant difference of infarction areas on day 3 was detected only between the MSC-HGF group and the PBS group with the superacute treatment, but was detected among each group on day 14 with both transplantations. After the superacute transplantation, we detected abundant expression of HGF protein in the ischemic brain of the MSC-HGF group compared with others on day 1 after treatment, and it was maintained for at least 2 weeks. Furthermore, we determined that the increased expression of HGF was derived from the transferred HGF gene in gene-modified MSCs. The percentage of apoptosis-positive cells in the ischemic boundary zone (IBZ) was significantly decreased, while that of remaining neurons in the cortex of the IBZ was significantly increased in the MSC-HGF group compared with others. The present study shows that combined therapy is more therapeutically efficient than MSC cell therapy alone, and it may extend the therapeutic time window from superacute to acute phase.

Caspase cascade of Fas-mediated apoptosis in human normal endometrium and endometrial carcinoma cells

Human endometrial epithelial cells undergo apoptosis immediately before the menstrual period. Apoptotic signalling was analysed using human endometrial tissue and a human endometrial carcinoma cell line (HHUA). Activity levels of caspase-3, -8, and -9 were elevated in human endometrium during the late secretory phase and in HHUA cells incubated with an anti-Fas monoclonal antibody (mAb). Fas-mediated apoptosis of HHUA cells was blocked by prior exposure to inhibitors of caspase-9, -8 and -3. In HHUA cells treated with anti-Fas mAb, a release of cytochrome c was detected in the cytosolic fraction, in addition a full-length Bid was degraded. Full-length FLIP(L) (p55) was degraded during apoptosis, and p29 (regarded as the product of p55 cleavage) appeared instead of FLIP(L). In normal human endometrial tissue, Bid degradation was also observed in a cyclic manner with a peak during the early secretory phase of the menstrual cycle. Furthermore, the release of cytochrome c was seen in the early secretory phase. However, expression of FLIP(S) was only observed during the menstrual cycle in normal endometrial tissue. We concluded that the main apoptotic signalling in both normal human endometrial tissue and HHUA cells exposed to anti-Fas mAb is the mitochondrial pathway via Bid degradation. Although the function of FLIP is still unknown on normal endometrial tissue, it may be regulated by FLIP(L) expression on HHUA cells derived from human endometrial carcinoma.

Method of specific detection of apoptosis using formamide-induced DNA denaturation assay

We compared the reliability between apoptosis detection methods, namely, the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) method and formamide-induced DNA denaturation assay using a monoclonal antibody (MAb) to single-stranded DNA (ssDNA) (formamide-MAb assay). Reaction targets in these methods are different: the TUNEL method recognizes free 3'-OH DNA ends, whereas the formamide-MAb assay detects ssDNA itself (25-30 bp). We found that the formamide-MAb assay immunohistochemically detected apoptotic cells, whereas the TUNEL method detected apoptotic cells as well as mitotic and necrotic cells. The TUNEL method recognized not only 3'-OH DNA ends cleaved by DNase during apoptosis but also constitutive physiological nicking that occurs in DNA duplication and histone posttranslational modifications during mitosis and random DNA breaks during necrotic execution. By electron microscopy, the mean labeling density (the number of 3'-OH DNA ends/nuclear area) obtained by the TUNEL method was determined to be consistently higher than that (the number of ssDNAs/nuclear area) obtained by the formamide-MAb assay. On the basis of these findings, we conclude that the formamide-MAb assay was more specific than the TUNEL method for the detection of apoptotic cells using electron microscopy; however, the labeling intensity of the formamide-MAb assay was slightly weaker than that of the TUNEL method.

In vivo electrogene transfer ofinterleukin-12 inhibits tumor growth and lymph node and lung metastases in mouse mammary carcinomas

BACKGROUND

Human breast cancer metastasizes mainly to lymph nodes, lungs, liver, and bone; in the majority of cases, it is the development of metastases which leads to death. In order to suppress mammary cancer metastasis, we applied in vivo electrogene transfer (non-viral method) as a means of interleukin-12 (IL-12) gene therapy on highly metastatic murine mammary cancer model.

METHODS

Metastatic mammary tumors induced by inoculation in BALB/c female mice were treated by intratumoral injections of either a plasmid vector containing IL-12 or empty vector and then subjected to in vivo electrogene transfer once a week for 8 weeks.

RESULTS

Treatment with IL-12 resulted in elevation of both IL-12 and IFNgamma levels in mammary tumors and in serum and intratumoral levels of CD4 and CD8 proteins were also increased. Tumor volumes and lymphatic and pulmonary metastases were significantly reduced. The histopathological changes induced by IL-12 characteristically included marked inflammation, increased apoptosis, decreased DNA synthesis, peripheral influx of significantly greater numbers of active macrophages, and reduced blood microvessel density, and apoptotic vascular endothelial cells were frequently seen. Western blotting showed decreases in VEGFR-3 of tumors exposed to IL-12 gene therapy. In adjuvant immunofluorescence studies, the CD31-positive endothelial cells of microvessels showed decreased VEGFR-3 expression in IL-12-treated tumors. However, apparent alterations in VEGFR-3 expression of podoplanin-positive lymphatic endothelial cells were not observed in IL-12-treated tumors. Although recombinant IL-12 did not inhibit tubular formation of human umbilical vein endothelial cells in a Matrigel assay, recombinant IFNgamma did completely suppress the tubular formation.

CONCLUSIONS

In vivo electrogene transfer of IL-12 exerts strong anti-tumorigenic and anti-metastatic effects likely due to T-cell-mediated immune responses as well as anti-angiogenic action.

Effect of Smad7 expression on metastasis of mouse mammary carcinoma JygMC(A) cells

BACKGROUND

Transforming growth factor beta (TGF-beta) facilitates metastasis during the advanced stages of cancer. Smad6, Smad7, and c-Ski block signaling by the TGF-beta superfamily proteins through different modes of action. We used adenovirus-mediated gene transfer of these natural inhibitors in a mouse model of breast cancer to examine the roles of TGF-beta superfamily signaling in tumor growth and metastasis.

METHODS

We systemically administered, by intravenous injection, adenoviruses (AdCMV) containing the mouse cDNAs for Smad7, Smad6, c-Ski, the c-Ski mutant c-Ski (ARPG), or LacZ (control) to nude mice (>19 mice/group) bearing tumors derived from mouse mammary carcinoma JygMC(A) cells, which spontaneously metastasize to lung and liver, and examined their effects on survival and metastasis. High-throughput western blotting analysis was used to examine the expression levels for 47 signal transduction proteins in JygMC(A) cells and primary tumors. We also investigated the proliferation, migration, and invasion of JygMC(A) cells that stably overexpressed Smad6 or Smad7. Nonparametric comparisons were done by Kruskal-Wallis H statistic and Wilcoxon's rank sum tests. Parametric comparisons were done by one-way analysis of variance or two-sided unpaired Student's t tests. All statistical tests were two-sided.

RESULTS

Control mice bearing tumors derived from JygMC(A) cells showed many metastases to the lung and liver; all animals died by 50 days after cell inoculation. By contrast, mice treated with AdCMV-Smad7 or AdCMV-c-Ski demonstrated a dramatic decrease in metastasis and statistically significantly longer survival than control mice (Smad7 versus LacZ: medium survival = 55 days versus 41 days, difference = 14 days [95% confidence interval {CI} = 6 days to 22 days], P < .001), whereas mice treated with AdCMV-Smad6 or AdCMV-c-Ski (ARPG) did not. Expression of Smad7 in JygMC(A) cells was associated with increased expression of major components of adherens and tight junctions, including E-cadherin, decreased expression of N-cadherin, and decreases in the migratory and invasive abilities of the JygMC(A) cells.

CONCLUSION

Smad7 inhibits metastasis, possibly by regulating cell-cell adhesion. Systemic expression of Smad7 may be a novel strategy for the prevention of metastasis of advanced cancers.

Bone Marrow Stromal Cells That Enhanced Fibroblast Growth Factor-2 Secretion by Herpes Simplex Virus Vector Improve Neurological Outcome After Transient Focal Cerebral Ischemia in Rats

Background and Purpose— Fibroblast growth factor-2 (FGF-2) administration and bone marrow stromal cell (MSC) transplantation could improve neurological deficits after occlusive cerebrovascular disease. In the present study, we examined the effects of neurological improvement after transient middle cerebral artery occlusion (MCAO) in rats by a novel therapeutic strategy with FGF-2 gene–transferred MSCs by the herpes simplex virus type 1 (HSV-1) vector.

Methods— Adult Wistar rats were anesthetized. Nonmodified MSCs, FGF-2–modified MSCs with HSV-1 1764/-4/pR19/ssIL2-FGF-2, or PBS was administered intracerebrally 24 hours after transient right MCAO. All animals underwent behavioral tests for 21 days, and the infarction volume with 2-3-5-triphenylterazolium was detected 3 days and 14 days after the MCAO. Three days and 7 days after the MCAO, the FGF-2 production in the ipsilateral hemisphere of the MCAO was measured with ELISA. Seven and 14 days after the MCAO, immunohistochemical staining for FGF-2 was applied.

Results— The stroke animals receiving FGF-2–modified MSCs demonstrated significant functional recovery compared with the other groups. Fourteen days after the MCAO, there was a significant reduction in infarction volume only in FGF-2–modified MSC-treated group. FGF-2 production in the FGF-2–modified MSC-treated brain was significantly higher compared with the other groups at 3 and 7 days after MCAO. Administrated FGF-2–modified MSCs strongly expressed the FGF-2 protein, which was proven by ELISA.

Conclusions— Our data suggest that the FGF-2 gene–modified MSCs with the HSV-1 vector can contribute to remarkable functional recovery after stroke compared with MSCs transplantation alone.

Electrogene transfer of an Epstein-Barr virus-based plasmid replicon vector containing the diphtheria toxin A gene suppresses mammary carcinoma growth in SCID mice

Experimental mammary cancer therapy in mice was conducted using electrogene transfer of a non-viral EBV-based plasmid vector (reduced size of the oriP gene), containing the DT-A gene. Because the EBV-based plasmid vector exhibits high transfer efficiency and strong persistent transgene expression due to autonomous replication in human cells, it is particularly suitable as a tool for cancer gene therapy. In vitro, 79% of MDA-MB231 human mammary carcinoma cells died as a result of the EBV-based vector containing DT-A (pEB-DTA) by 48 h after transfection. DNA synthesis was also significantly decreased as compared to levels with a control vector. In vivo, mammary tumors induced by inoculation of SCID mice with MDA-MB231 cells were subsequently treated by direct injection of pEB-DTA vector or pEB-GFP vector as a control once a week for 5 weeks. After each injection, the tumors were subjected to in vivo electrogene transfer. Significantly reduced tumor volumes were observed for the pEB-DTA group in experimental week 1 and thereafter throughout the study. At necropsy, strong and extent expression of GFP was still observed in tumors receiving pEB-GFP 6 days after the last electrogene transfer. The ratio of histological necrotic area to viable area was significantly increased in the pEB-DTA-treated tumors, where levels of apoptosis were significantly higher than those observed in the pEB-GFP group. DNA synthesis showed a tendency to decrease in the pEB-DTA group but this was not significant. The incidence and multiplicity of lung metastasis were similar between the groups. There was also no difference in the density of microvessels between groups. We therefore conclude that the EBV-based plasmid vector system combined with in vivo electrogene transfer can result in efficient gene transfection and that the non-viral replicon vector containing DT-A suppresses tumor growth due to apoptotic cell death in this model.

Perforin improves the morphogenesis of mouse placenta disturbed by IL-2 treatment

The pore-forming protein (perforin) produced by lymphocytes can induce apoptosis in target cells. In mouse placenta, although a large amount of perforin is produced by the uterine natural killer (uNK) cells, its role in the reproductive process is still not clear. Since the cytotoxicity of uNK cells can be enhanced by interleukin (IL)-2, we studied the role of perforin in the placenta of wild-type and perforin-knockout mice treated with IL-2 during days 10-14 of pregnancy. Immunohistochemistry of the wild-type mice showed that the perforin was positive in the membrane of trophoblast glycogen cells as well as the cytoplasm of uNK cells, and there was an increase in the expression level following IL-2 treatment as revealed by RT-PCR analysis, although no change was identified in fertility. In the IL-2-treated perforin-knockout mice, however, the number of live fetuses was decreased, accompanied by an increase in the weight of placentae. Examination of these placentae showed an abnormally enlarged junctional zone, occupied by a large number of the trophoblast glycogen cells and significantly few of the apoptotic cells. These findings indicate that perforin can contribute to a successful pregnancy by inhibiting the excessive growth of the junctional zone induced by IL-2.

Evaluation of cell death and proliferation in psoriatic epidermis

BACKGROUND

Previous studies of psoriatic epidermis using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) method, a type of apoptotic detection method, showed that TUNEL-positive keratinocytes were abundantly distributed in all layers of the psoriatic epidermis, although psoriasis is a hyperproliferative disorder.

OBJECTIVE

We sought to clarify the nature of cell kinetics in a psoriatic epidermis on the basis of differences in the reactivities in TUNEL and formamide-induced DNA denaturation assay combined with the detection of denatured DNA with a monoclonal antibody (MAb) against single-stranded DNA (formamide-MAb assay) between the normal and psoriatic epidermides.

METHODS

The kinetics of keratinocytes was evaluated by the immunohistochemistry of Ki-67 for proliferation activity and by TUNEL, TUNEL combined with transmission electron microscopy (TUNEL/TEM), and formamide-MAb assay for apoptosis.

RESULTS

The number of Ki-67-positive cells in the psoriatic epidermis was significantly higher than that in the normal epidermis. In the normal epidermis, both TUNEL and formamide-MAb assay showed a similar distribution pattern, that is, both TUNEL and formamide-MAb assay-positive keratinocytes were present only in the upper granular layer. In the psoriatic epidermis, most keratinocytes were negative for the formamide-MAb assay, while TUNEL-positive cells were abundantly distributed in all layers of the psoriatic epidermis. TUNEL/TEM method clearly demonstrated that many immunogold particles that stain the sites of 3'-OH DNA ends were evenly distributed on the euchromatin in psoriatic keratinocyte nuclei, in contrast to their presence on the peripheral condensed chromatin in normal keratinocyte nuclei.

CONCLUSION

The increased TUNEL reactivity in psoriatic lesions is due to the increase in the number of DNA nicks resulting from active DNA replication but not due to DNA double-strand breaks produced during the apoptotic process, and the formamide-MAb assay is a reliable method for the detection of apoptosis, particularly in the epidermis.

Tissue specificity of apoptotic signal transduction

Two major apoptotic pathways exist in mammalian cells: the death receptor and mitochondrial pathways. The cross talk between these two pathways is minimal, and they operate basically independent of each other under physiological conditions. Therefore, the tissue specificity of the signal pathway during apoptosis is observed in various tissues and organs. In this article, I demonstrate several examples of apoptosis induced by different signal pathways: apoptosis of human amniotic epithelial cells upon fetal membrane rupture induced by the death receptor pathway, apoptosis of human endometrial cells shed via menstruation and in the selection of B cells in gut-associated lymphoid tissues induced by both the death receptor and mitochondrial pathways, and apoptosis of lovastatin-induced breast cancer cells induced by the mitochondrial pathway.

Involvement of the Fas Ligand and Fas System in Apoptosis Induction of Mouse Uterine Natural Killer Cells

Uterine natural killer (uNK) cells in the pregnant uterus are known to be associated with the normal development of the placenta. In the mouse pregnant uterus, many uNK cells exist during mid pregnancy, although they show a sudden decrease during late pregnancy and almost disappear before delivery. Our previous study indicated that uNK cells showed clear apoptotic morphology during late pregnancy. Therefore, the present study was carried out to define the involvement of Fas ligand (FasL) and Fas in apoptosis induction of uNK cells. Immunohistochemical analyses revealed that uNK cells expressed FasL in the cytoplasmic granules and Fas on the cell membrane during late pregnancy. In lpr/lpr mice, which genetically lack Fas, many uNK cells were clearly observed during late pregnancy compared with wild-type mice, and moreover uNK cells still existed at day-18 of pregnancy, although there were few in wild-type mice during the same period. In the experiment of in vitro culture, uNK cells derived from wild-type placenta showed chromatin condensation and DNA fragmentation frequently following the anti-Fas antibody treatment, as compared with the control. From these results, it is suggested that FasL and Fas-dependent apoptosis regulates cell appearance of uNK cells in the mouse pregnant uterus.

Involvement of angiopoietins in cancer progression in association with cancer cell--fibroblast interaction

PURPOSE

The role of angiopoietins (ANGs) in cancer progression is a new field of research. We examined the patterns of expression of ANGs in human renal cancer tissues (n =12) and investigated their roles in cancer progression in vitro and in vivo.

METHODS AND RESULTS

In normal renal tissue, the expression of ANG-1 was apparent in the glomerular capillaries and podocytes as well as in the endothelial cells of vessels, whereas we observed no expression of ANG-2. In contrast, in tumor tissue, dense, diffuse expression of ANG-1 was apparent in the fibroblasts, but not in the cancer cells. Intense ANG-2 expression was observed in the cancer cells themselves as well as in the endothelial cells, where its expression was restricted to small vessels or neoplastic capillaries and not mature vessels. Secondly, we investigated the influence of fibroblasts on the production of angiopoietins in cancer cells, using the human renal cancer cell lines SN12 and SN-PM6 and a human dermal fibroblast cell line (HDF). We examined the in vitro production of angiopoietins in these cell lines, in either monoculture of each cell line or co-culture of cancer cells and fibroblasts. Immunohistochemical study demonstrated marked production of ANG-1 in fibroblasts and ANG-2 expression in cancer cells when we performed co-culture, but no expression of either in each monoculture. Western blot analysis confirmed these results, showing marked expression of ANGs in co-cultured cells, but not in each monoculture.

CONCLUSION

Fibroblasts may influence cancer progression by promoting neoplastic angiogenesis, and ANGs are profoundly involved in this process through their association with the carcinoma cell-fibroblast interaction.

A novel STK11 germline mutation in two siblings with Peutz-Jeghers syndrome complicated by primary gastric cancer

Patients with Peutz-Jeghers syndrome (PJS) are known to be at risk of gastric cancer (GC), and the STK11 gene is a susceptibility gene for PJS. However, as no cases of PJS with GC in which a STK11 germline mutation has been identified have ever been reported and other susceptibility genes have also been suggested to be involved in PJS, the relation between STK11 germline mutations and GC in PJS is still unknown. In this study, we used sequencing analysis to investigate the STK11, CDH1, and TP53 loci for a germline mutation in two siblings with PJS with primary GC. A novel type of the STK11 germline mutation, c.890delG, encoding a truncated protein (p.Arg297fsX38) was identified, but no germline mutations of the CDH1 and TP53 genes were detected. No inactivation of the wild-type allele by somatic mutation or chromosomal deletion or hypermethylation at the 5'-CpG site of STK11 was detected in the GC. This is the first report of a STK11 germline mutation in a PJS patient with GC and should contribute to establishing correlations between the STK11 germline mutations and GC in PJS patients.