A rapid and transient ROS generation by cadmium triggers apoptosis via caspase-dependent pathway in HepG2 cells and this is inhibited through N-acetylcysteine-mediated catalase upregulation

Although reactive oxygen species (ROS) have been implicated in cadmium (Cd)-induced hepatotoxicity, the role of ROS in this pathway remains unclear. Therefore, we attempted to determine the molecular mechanisms relevant to Cd-induced cell death in HepG2 cells. Cd was found to induce apoptosis in the HepG2 cells in a time- and dose-dependent fashion, as confirmed by DNA fragmentation analysis and TUNEL staining. In the early stages, both rapid and transient ROS generation triggered apoptosis via Fas activation and subsequent caspase-8-dependent Bid cleavage, as well as by calpain-mediated mitochondrial Bax cleavage. The timing of Bid activation was coincided with the timing at which the mitochondrial transmembrane potential (MMP) collapsed as well as the cytochrome c (Cyt c) released into the cytosol. Furthermore, mitochondrial permeability transition (MPT) pore inhibitors, such as cyclosporin A (CsA) and bongkrekic acid (BA), did not block Cd-induced ROS generation, MMP collapse and Cyt c release. N-acetylcysteine (NAC) pretreatment resulted in the complete inhibition of the Cd-induced apoptosis via catalase upregulation and subsequent Fas downregulation. NAC treatment also completely blocked the Cd-induced intracellular ROS generation, MMP collapse and Cyt c release, indicating that Cd-induced mitochondrial dysfunction may be regulated indirectly by ROS-mediated signaling pathway. Taken together, a rapid and transient ROS generation by Cd triggers apoptosis via caspase-dependent pathway and subsequent mitochondrial pathway. NAC inhibits Cd-induced apoptosis through the blocking of ROS generation as well as the catalase upregulation.

Development of a novel bone grafting material using autogenous teeth

We developed a novel bone grafting material that incorporates autogenous teeth (AutoBT), and provided the basis for its clinical application. AutoBT contains organic and inorganic mineral components and is prepared from autogenous grafting material, thus eliminating the risk of an immune reaction that may lead to rejection. AutoBT was used at the time of implant placement, simultaneously with osteoinduction surgery, and excellent bony healing by osteoinduction and osteoconduction was confirmed.

Endoplasmic reticulum stress-mediated autophagy/apoptosis induced by capsaicin (8-methyl-N-vanillyl-6-nonenamide) and dihydrocapsaicin is regulated by the extent of c-Jun NH2-terminal kinase/extracellular signal-regulated kinase activation in WI38 lung epithelial fibroblast cells

Endoplasmic reticulum (ER) stress causes cell survival or death, which is dependent on the type of cell and stimulus. Capsaicin (8-methyl-N-vanillyl-6-nonenamide) and its analog, dihydrocapsaicin (DHC), induced caspase-3-independent/-dependent signaling pathways in WI38 lung epithelial fibroblast cells. Here, we describe the molecular mechanisms induced by both chemicals. Exposure to capsaicin or DHC caused induction of p53, p21, and G(0)/G(1) arrest. DHC induced massive cellular vacuolization by dilation of the ER and mitochondria. Classic ER stress inducers elicited the unfolded protein response (UPR) and up-regulation of microtubule-associated protein 1 light chain-3 (LC3) II. DHC induced ER stress by the action of heavy chain-binding protein, IRE1, Chop, eukaryotic initiation factor 2alpha, and caspase-4 and, to a lesser level, by capsaicin treatment. DHC treatment induced autophagy that was blocked by 3-methyladenine (3MA) and accumulated by bafilomycin A1. Blocking of DHC-induced autophagy by 3MA enhanced apoptotic cell death that was completely inhibited by treatment of cells with benzyl-oxcarbonyl-Val-Ala-Asp-fluoromethyl ketone. Knockdown of Ire1 down-regulated the DHC-induced Chop and LC3II and enhanced caspase-3 activation. DHC induced rapid and high-sustained c-Jun NH(2)-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK) activation, but capsaicin induced transient activation of JNK/ERK. The JNK inhibitor SP600125 down-regulated the expression of IRE1, Chop, and LC3II induced by DHC, thapsigargin, and MG132 [N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal]. Pharmacological blockade or knockdown of ERK down-regulated LC3II. Capsaicin and DHC induced Akt phosphorylation, and the phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride], induced autophagy via ERK activation. Our results indicate that the differential responses of capsaicin and DHC for cell protection are caused by the extent of the UPR and autophagy that are both regulated by the level of JNK and ERK activation.

CD24 and human carcinoma: tumor biological aspects

CD24 is a mucin-like adhesion molecule that has recently raised attention and lent substantial improvements for our understanding of tumor biology. Functionally, CD24 enhances the metastatic potential of malignant-cells, because it has been identified as a ligand of P-selectin, an adhesion receptor on activated endothelial cells and platelets. Moreover, it has been described as a diagnostic molecular marker of malignant tumor and for patient prognosis. This article reviews the experimental and clinical data on CD24 expression and carcinomas from the point of view of tumor biology. Based on the research, CD24 expression will be analyzed as a potentially significant parameter for a wide variety of human cancer diagnoses. Understanding the functions and implications CD24 might aid the clinician in the selection of an appropriate therapy for individual patients: for example, the intravenous administration of C1324-specific antibodies to treat cancers.

Interleukin-22 promotes epithelial cell transformation and breast tumorigenesis via MAP3K8 activation

Interleukin-22 (IL-22), one of the cytokines secreted by T-helper 17 (Th17) cells, binds to a class II cytokine receptor containing an IL-22 receptor 1 (IL-22R1) and IL-10R2 and influences a variety of immune reactions. IL-22 has also been shown to modulate cell cycle and proliferation mediators such as extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but little is known about the underlying molecular mechanisms of IL-22 in tumorigenesis. In this paper, we propose that IL-22 has a crucial role to play in controlling epithelial cell proliferation and tumorigenesis in the breast. IL-22 increased MAP3K8 phosphorylation through IL-22R1, followed by the induction of MEK-ERK, JNK-c-Jun, and STAT3 signaling pathways. Furthermore, IL-22-IL-22R1 signaling pathway activated activator protein-1 and HER2 promoter activity. In addition, Pin1 was identified as a key positive regulator for the phosphorylation-dependent MEK, c-Jun and STAT3 activity induced by IL-22. Pin1(-/-) mouse embryonic fibroblasts (MEF) exhibited significantly a decrease in IL-22-induced MEK1/2, c-Jun, and STAT3 phosphorylation compared with Pin1(+/+) MEF. In addition, a knockdown of Pin1 prevented phosphorylation induced by IL-22. The in vivo chorioallantoic membrane assay also showed that IL-22 increased tumor formation of JB6 Cl41 cells. Moreover, the knockdown of MAP3K8 and Pin1 attenuated tumorigenicity of MCF7 cells. Consistent with these observations, IL-22 levels positively correlate with MAP3K8 and Pin1 expression in human breast cancer. Overall, our findings point to a critical role for the IL-22-induced MAP3K8 signaling pathway in promoting cancer-associated inflammation in the tumor microenvironment.

Gα12 overexpression induced by miR-16 dysregulation contributes to liver fibrosis by promoting autophagy in hepatic stellate cells

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) have a role in liver fibrosis. Guanine nucleotide-binding α-subunit 12 (Gα12) converges signals from G-protein-coupled receptors whose ligand levels are elevated in the environment during liver fibrosis; however, information is lacking on the effect of Gα12 on HSC trans-differentiation. This study investigated the expression of Gα12 in HSCs and the molecular basis of the effects of its expression on liver fibrosis.

METHODS

Gα12 expression was assessed by immunostaining, and immunoblot analyses of mouse fibrotic liver tissues and primary HSCs. The role of Gα12 in liver fibrosis was estimated using a toxicant injury mouse model with Gα12 gene knockout and/or HSC-specific Gα12 delivery using lentiviral vectors, in addition to primary HSCs and LX-2 cells using microRNA (miR) inhibitors, overexpression vectors, or adenoviruses. miR-16, Gα12, and LC3 were also examined in samples from patients with fibrosis.

RESULTS

Gα12 was overexpressed in activated HSCs and fibrotic liver, and was colocalised with desmin. In a carbon tetrachloride-induced fibrosis mouse model, Gα12 ablation prevented increases in fibrosis and liver injury. This effect was attenuated by HSC-specific lentiviral delivery of Gα12. Moreover, Gα12 activation promoted autophagy accompanying c-Jun N-terminal kinase-dependent ATG12-5 conjugation. In addition, miR-16 was found to be a direct inhibitor of the de novo synthesis of Gα12. Modulations of miR-16 altered autophagy in HSCs. In a fibrosis animal model or patients with severe fibrosis, miR-16 levels were lower than in their corresponding controls. Consistently, cirrhotic patient liver tissues showed Gα12 and LC3 upregulation in desmin-positive areas.

CONCLUSIONS

miR-16 dysregulation in HSCs results in Gα12 overexpression, which activates HSCs by facilitating autophagy through ATG12-5 formation. This suggests that Gα12 and its regulatory molecules could serve as targets for the amelioration of liver fibrosis.

LAY SUMMARY

Guanine nucleotide-binding α-subunit 12 (Gα12) is upregulated in activated hepatic stellate cells (HSCs) as a consequence of the dysregulation of a specific microRNA that is abundant in HSCs, facilitating the progression of liver fibrosis. This event is mediated by c-Jun N-terminal kinase-dependent ATG12-5 formation and the promotion of autophagy. We suggest that Gα12 and its associated regulators could serve as new targets in HSCs for the treatment of liver fibrosis.

Inhibition of liver fibrosis by solubilized coenzyme Q10: Role of Nrf2 activation in inhibiting transforming growth factor-beta1 expression

Coenzyme Q10 (CoQ10), an endogenous antioxidant, is important in oxidative phosphorylation in mitochondria. It has anti-diabetic and anti-cardiovascular disease effects, but its ability to protect against liver fibrosis has not been studied. Here, we assessed the ability of solubilized CoQ10 to improve dimethylnitrosamine (DMN)-induced liver fibrogenesis in mice. DMN treatments for 3 weeks produced a marked liver fibrosis as assessed by histopathological examination and tissue 4-hydroxyproline content. Solubilized CoQ10 (10 and 30 mg/kg) significantly inhibited both the increases in fibrosis score and 4-hydroxyproline content induced by DMN. Reverse transcription-polymerase chain reaction and Western blot analyses revealed that solubilized CoQ10 inhibited increases in the transforming growth factor-beta1 (TGF-beta1) mRNA and alpha-smooth muscle actin (alpha-SMA) protein by DMN. Interestingly, hepatic glutamate-cysteine ligase (GCL) and glutathione S-transferase A2 (GSTA2) were up-regulated in mice treated with CoQ10. Solubilized CoQ10 also up-regulated antioxidant enzymes such as catalytic subunits of GCL and GSTA2 via activating NF-E2 related factor2 (Nrf2)/antioxidant response element (ARE) in H4IIE hepatoma cells. Moreover, CoQ10's inhibition of alpha-SMA and TGF-beta1 expressions disappeared in Nrf2-null MEF cells. In contrast, Nrf2 overexpression significantly decreased the basal expression levels of alpha-SMA and TGF-beta1 in Nrf2-null MEF cells. These results demonstrated that solubilized CoQ10 inhibited DMN-induced liver fibrosis through suppression of TGF-beta1 expression via Nrf2/ARE activation.

Atypical ductal hyperplasia diagnosis by directional vacuum-assisted stereotactic biopsy of breast microcalcifications. Considerations for surgical excision

In 824 patients who underwent directional vacuum-assisted biopsies (DVABs) of breast microcalcifications, 61 (7.4%) showed atypical ductal hyperplasia (ADH). The 42 who subsequently underwent excision were the subjects of this study. Cases were evaluated for the mammographic characteristics of the lesion, the percentage of lesion removed according to mammography, and histologic findings (including number of large ducts and/or terminal duct-lobular units involved with ADH) in DVAB specimens. Pathologic findings in the surgical specimens in the area of the biopsy site also were recorded. In the DVAB specimens, ADH was confined to an average of 1.5 large ducts or lobular units and was associated with microcalcifications in all of the patients. Surgical specimens showed ADH in 15 cases, no residual lesion in 24 cases, and ductal carcinoma in situ in 3 cases. We found that microcalcifications that contain ADH in less than 3 lobules or ducts and/or that are removed completely by DVAB do not reveal higher-risk lesions on excision; thus, removal is unnecessary. When assessing microcalcifications with ADH, clinicians should consider the percentage of microcalcifications removed by DVAB and the extent of lobular involvement to better assess the need for excision.

Cadmium induces apoptotic cell death in WI 38 cells via caspase-dependent Bid cleavage and calpain-mediated mitochondrial Bax cleavage by Bcl-2-independent pathway

Previous reports have demonstrated that cadmium (Cd) may induce cell death via apoptosis, but the mechanism responsible for cellular death is not clear. In this study, we investigated the signaling pathways implicated in Cd-induced apoptosis in lung epithelial fibroblast (WI 38) cells. Apoptotic features were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, propidium iodide staining and DNA laddering. A treatment of cadmium caused the caspase-8-dependent Bid cleavage, the release of cytochrome c (Cyt c), activation of caspase-9 and -3, and PARP cleavage. A caspase-8 specific inhibitor prevented the Bid cleavage, caspase-3 activation and cell death. Alternatively, we observed that full-length Bax was cleaved into 18-kDa fragment (p18/Bax); this was initiated after 12 h and by 36 h the full-length Bax protein was totally cleaved to the p18/Bax, which caused a drastic release of Cyt c from mitochondria. The p18/Bax was detected exclusively in the mitochondrial fraction, and it originated from mitochondrial full-length Bax, but not from the cytosol full-length Bax. Cd also induced the activation of the mitochondrial 30-kDa small subunit of calpain that was preceded by Bax cleavage. Cd induced the upregulation of Bcl-2 and the degradation of p53 protein. N-acetyl cysteine effectively inhibited the Cd-induced DeltaPsim reduction, indicating ROS acts upstream of mitochondrial membrane depolarization. Taken together, our results suggest that Cd-induced apoptosis was thought to be mediated at least two pathways; caspase-dependent Bid cleavage, and the other is calpain-mediated mitochondrial Bax cleavage. Moreover, we found that the function of Bid and Bax was not dependent of Bcl-2, and that ROS can also contribute in the Cd-induced cell death.

Interleukin-33/ST2 axis promotes epithelial cell transformation and breast tumorigenesis via upregulation of COT activity

Cytokines of the interleukin-1 (IL-1) family, such as IL-1α/β and IL-18, have pleiotropic activities in innate and adaptive immune responses in host defense and diseases. Insight into their biological functions helped develop novel therapeutic approaches to treat human inflammatory diseases. IL-33 is an important member of the IL-1 family of cytokines and is a ligand of the ST2 receptor, a member of the IL-1 receptor family. However, the role of the IL-33/ST2 axis in tumor growth and metastasis of breast cancer remains unclear. Here, we demonstrate that IL-33 is a critical tumor promoter during epithelial cell proliferation and tumorigenesis in the breast. IL-33 dose- and time-dependently increased Cancer Osaka Thyroid (COT) phosphorylation via ST2-COT interaction in normal epithelial and breast cancer cells. The IL-33/ST2/COT cascade induced the activation of the MEK-ERK (MEK-extracellular signal-regulated kinase), JNK-cJun (cJun N-terminal kinase-cJun) and STAT3 (signal transducer and activator of transcription 3) signaling pathways, followed by increased AP-1 and stat3 transcriptional activity. When small interfering RNAs of ST2 and COT were introduced into cells, IL-33-induced AP-1 and stat3 activity were significantly decreased, unlike that in the control cells. The inhibition of COT activity resulted in decreased IL-33-induced epithelial cell transformation, and knockdown of IL-33, ST2 and COT in breast cancer cells attenuated tumorigenicity of breast cancer cells. Consistent with these observations, ST2 levels were positively correlated with COT expression in human breast cancer. These findings provide a novel perspective on the role of the IL-33/ST2/COT signaling pathway in supporting cancer-associated inflammation in the tumor microenvironment. Therapeutic approaches that target this pathway may, therefore, effectively inhibit carcinogenesis in the breast.

The role of CD24 in various human epithelial neoplasias

CD24 is a small, heavily glycosylated glycosylphosphatidylinositol-linked cell surface protein, which is expressed in hematologic malignancies and in a large variety of solid tumors. It appears to function as a ligand of P-selectin, an adhesion molecule present in activated platelets and endothelial cells. The authors aimed at evaluating CD24 protein expression in adenoma and adenocarcinoma of the stomach, colon, gallbladder, ovary, and breast to establish a correlation with clinicopathologic data. Staining was evaluated using four degrees of positivity (negative, weakly, moderately, strongly positive), and the staining patterns (membranous vs. intracytoplasmic) were analyzed for statistical analysis. The present study clearly demonstrates that CD24 is abundantly expressed in adenocarcinoma compared to adenoma of the colon and breast. Moreover, the positivity degree of CD24 expression increases with positive nodal status in advanced gastric carcinoma. Intracytoplasmic CD24 expression was found to be highly associated with adenocarcinoma of the colon, gallbladder, and ovary compared to the adenoma group of those organs, and with the positive nodal status compared to the negative nodal status of the colonic adenocarcinoma. We conclude that the degree of positivity and the staining pattern of CD24 constitute an important molecular marker for various epithelial neoplasms, which could help to define malignant transformation and to predict lymph node metastasis.

Effect of betulinic acid on anticancer drug-resistant colon cancer cells

Primary or acquired resistance of tumours to established chemotherapeutic regimens is a major concern in oncology. Attempts to improve the survival of cancer patients largely depend on strategies to prevent tumour cell resistance. 5-Fluorouracil (5-FU)-based chemotherapy with a combination of other drugs such as irinotecan (IRT) and oxaliplatin (OXT) has been reported to be effective, even though an optimal regimen has yet to be defined due to the relatively high toxicity of the procedure. The aim of this study was to examine the effect of betulinic acid (BetA) as a chemosensitizer for anticancer drug treatment in chemoresistant colon cancer cell lines. A chemoresistant cell line to 5-fluorouracil (SNU-C5/5FU-R), irinotecan (SNU-C5/IRT-R) and oxaliplatin (SNU-C5/OXT-R) treatment were derived from the wild-type colon adenocarcinoma cell line (SNU-C5/WT). The effect of BetA or a combination of anticancer drugs and BetA on the multidrug resistance-related genes, caspases, Bcl-2, Bad and cell death in the SNU-C5/WT and SNU-C5/R cell lines was analysed. BetA alone was an effective chemotherapeutic drug for the SNU-C5/WT, SNU-C5/5FU-R and SNU-C5/OXT-R cells. The combination of BetA with IRT or OXT was effective against SNU-C5/5FU-R cells, and the combination of BetA with 5-fluorouracil, IRT or OXT was effective against SNU-C5/OXT-R cells. BetA induced cancer cell death by apoptosis through the mitochondrial pathway. These findings indicate that the use of BetA as a chemosensitizer may be a new strategy to enhance the efficacy of chemotherapy. However, further studies will be needed for confirmation.

Role of PTEN promoter methylation in tamoxifen-resistant breast cancer cells

Tamoxifen (TAM) resistance is a serious clinical problem in the treatment of breast cancer. Here, we found that S-adenosylmethionine (SAM) and DNA methyltransferase1 (DNMT1) expression are up-regulated in TAM-resistant breast cancer (TAMR-MCF-7) cells. We further focused on whether increased SAM with DNMT1 overexpression in TAMR-MCF-7 cells lead to aberrant methylation of the PTEN gene promoter and its therapeutic potential. Methylation-specific PCR analyses revealed that two sites within the PTEN promoters were methylated in TAMR-MCF-7 cells, which resulted in down-regulation of PTEN expression and increase in Akt phosphorylation. Both the loss of PTEN expression and the increased Akt phosphorylation in TAMR-MCF-7 cells were completely reversed by 5-aza-2'-deoxycytidine (5-Aza), a DNMT inhibitor. 5-Aza inhibited the basal cell proliferation rate of TAMR-MCF-7 cells and intraperitoneal injection of 5-Aza significantly suppressed TAMR-MCF-7 tumor growth in a xenograft study. Immunohistochemistry showed that PTEN expression in TAM-resistant human breast cancer tissues was lower than in TAM-responsive cases. These results suggest that methylation of the PTEN promoter related to both SAM increase and DNMT1 activation contributes to persistent Akt activation and are potential therapeutic targets for reversing TAM resistance in breast cancer.

Tissue response to titanium plates: a transmitted electron microscopic study

PURPOSE

This study investigated the tissue response associated with titanium plates.

MATERIALS AND METHODS

Titanium miniplates were used to stabilize fractured bones and a bone graft in 14 patients. At the time of plate removal, the osteosynthesis sites were carefully examined macroscopically. After the removal of the plates, biopsies of the 14 soft tissues and two bony sites surrounding the plates were performed for light microscopic and transmitted electron microscopic examination.

RESULTS

Macroscopically, visible pigmentation was found in the soft tissue in 14% of the patients, but none in the bone. With light microscopy, pigmentation was found in the soft tissue of 10 of 14 sites and in one of two bony sites. Transmitted electron microscopy showed suspected titanium particles in the connective tissue of all specimens. The small particles were located between the collagen fibers. In some specimens, small particles were noted within the fibroblasts and macrophages. There were degenerative changes around the minute particles in the bone matrix.

CONCLUSION

Local macroscopic or microscopic tissue destruction was observed in hard and soft tissue near the titanium miniplates. If the plates remain for a long time, there is a possibility that they may cause further tissue damage. These findings suggest that the titanium miniplates should be removed routinely after bone healing.

Dihydrocapsaicin (DHC), a saturated structural analog of capsaicin, induces autophagy in human cancer cells in a catalase-regulated manner

Although capsaicin, a pungent component of red pepper, is known to induce apoptosis in several types of cancer cells, the mechanisms underlying capsaicin-induced cytotoxicity are unclear. Here, we showed that dihydrocapsaicin (DHC), an analog of capsaicin, is a potential inducer of autophagy. DHC was more cytotoxic than capsaicin in HCT116, MCF-7 and WI38 cell lines. Capsaicin and DHC did not affect the sub-G(1) apoptotic peak, but induced G(0)/G(1) arrest in HCT116 and MCF-7 cells. DHC caused the artificial autophagosome marker GFP-LC3 to redistribute and upregulated expression of autophagy-related proteins. Blocking of autophagy by 3-methyladenine (3MA) as well as siRNA Atg5 induced a high level of caspase-3 activation. Although pretreatment with zVAD completely inhibited caspase-3 activation by 3MA, it did not prevent cell death. DHC-induced autophagy was enhanced by zVAD pretreatment, as shown by increased accumulation of LC3-II protein. DHC attenuated basal ROS levels through catalase induction; this effect was enhanced by antioxidants, which increased both LC3-II expression and caspase-3 activation. The catalase inhibitor 3-amino-1,2,4-triazole (3AT) abrogated DHC-induced expression of LC3-II, overexpression of the catalase gene increased expression of LC3-II protein, and knockdown decreased it. Additionally, DHC-induced autophagy was independent of p53 status. Collectively, DHC activates autophagy in a p53-independent manner and that may contribute to cytotoxicity of DHC.

Essential role of Notch4/STAT3 signaling in epithelial-mesenchymal transition of tamoxifen-resistant human breast cancer

We previously demonstrated that tamoxifen (TAM)-resistant human breast cancer (TAMR-MCF-7) cells showed increased expression of mesenchymal marker proteins compared to the parent MCF-7 cells. Notch is functionally important in the promotion of epithelial-mesenchymal transition (EMT) during both development and tumor progression. Notch1 and Notch4 have been reported as prognostic markers in human breast cancer. Here, we indicated that Notch4, but not Notch1, plays a critical role in the regulation of EMT signaling in TAMR-MCF-7 cells. Notch4 suppression by either Notch inhibitors or Notch4 siRNA attenuated EMT signaling. Tyrosine-phosphorylated STAT3 protein is known as a crucial signaling molecule in the regulation of tumorigenesis and metastasis. We found that TAMR-MCF-7 cells exhibited constitutive STAT3 phosphorylation, and Notch inhibition reduced the level of activated STAT3 in TAMR-MCF-7 cells. An intrasplenic injection model of liver metastases was performed using TAMR-MCF-7 cells. Mice injected with N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT, 10 mg/kg) formed smaller splenic tumors and showed a reduced micrometastatic tumor burden in their livers compared with the control group treated with vehicle. To conclude, Notch4 could be a potential target to prevent metastasis in TAM-resistant breast cancer.

Hepatocellular cancer arises from loss of transforming growth factor beta signaling adaptor protein embryonic liver fodrin through abnormal angiogenesis

We have previously demonstrated that 40%-70% of elf(+/-) mice spontaneously develop hepatocellular cancer (HCC) within 15 months, revealing the importance of the transforming growth factor-beta (TGF-beta) signaling pathway in suppressing tumorigenesis in the liver. The current study was carried out to investigate mechanisms by which embryonic liver fodrin (ELF), a crucial Smad3/4 adaptor, suppresses liver tumor formation. Histological analysis of hyperplastic liver tissues from elf(+/-) mice revealed abundant newly formed vascular structures, suggesting aberrant angiogenesis with loss of ELF function. In addition, elf(+/-) mice displayed an expansion of endothelial progenitor cells. Ectopic ELF expression in fetal bovine heart endothelial (FBHE) cells resulted in cell cycle arrest and apoptosis. Further analysis of developing yolk sacs of elf(-/-) mice revealed a failure of normal vasculature and significantly decreased endothelial cell differentiation with embryonic lethality. Immunohistochemical analysis of hepatocellular cancer (HCC) from the elf(+/-) mice revealed an abnormal angiogenic profile, suggesting the role of ELF as an angiogenic regulator in suppressing HCC. Lastly, acute small interfering RNA (siRNA) inhibition of ELF raised retinoblastoma protein (pRb) levels nearly fourfold in HepG2 cells (a hepatocellular carcinoma cell line) as well as in cow pulmonary artery endothelial (CPAE) cells, respectively.

CONCLUSION

Taken together these results, ELF, a TGF-beta adaptor and signaling molecule, functions as a critical adaptor protein in TGF-beta modulation of angiogenesis as well as cell cycle progression. Loss of ELF in the liver leads the cancer formation by deregulated hepatocyte proliferation and stimulation of angiogenesis in early cancers. Our studies propose that ELF is potentially a powerful target for mimetics enhancing the TGF-beta pathway tumor suppression of HCC.

Early Bone Formation at a Femur Defect Using CGF and PRF Grafts in Adult Dogs: A Comparative Study

PURPOSE

The purpose of this study was to compare the predictability of new bone formation using an autologous concentrated growth factor (CGF) graft alone and platelet graft alone.

MATERIALS AND METHODS

Four bony defects of 8 mm were formed, and 3.7- × 10-mm implants were placed in the right femur. The platelet-rich fibrin (PRF), CGF, and synthetic bone were grafted to the bone defect area. Enzyme linked immunosorbent assay quantitative analysis and microscopic analysis of the fibrinogen structure were performed.

RESULTS

At 4 weeks, the comparisons of each experimental group showed a significant difference between the CGF group and the synthetic bone graft group. When comparing the CGF and allograft material groups, the allograft group showed significantly more new bone formation. In the case of vascular endothelial growth factor, CGF had 1.5 times more than PRF. CGF showed a fibrinogen structure with a constant diameter.

CONCLUSION

When applied to a clinical case, CGF is predicted to show better results than PRF.

The Korean guideline for cervical cancer screening

The incidence rate of cervical cancer in Korea is still higher than in other developed countries, notwithstanding the national mass-screening program. Furthermore, a new method has been introduced in cervical cancer screening. Therefore, the committee for cervical cancer screening in Korea updated the recommendation statement established in 2002. The new version of the guideline was developed by the committee using evidence-based methods. The committee reviewed the evidence for the benefits and harms of the Papanicolaou test, liquid-based cytology, and human papillomavirus (HPV) testing, and reached conclusions after deliberation. The committee recommends screening for cervical cancer with cytology (Papanicolaou test or liquid-based cytology) every three years in women older than 20 years of age (recommendation A). The cervical cytology combined with HPV test is optionally recommended after taking into consideration individual risk or preference (recommendation C). The current evidence for primary HPV screening is insufficient to assess the benefits and harms of cervical cancer screening (recommendation I). Cervical cancer screening can be terminated at the age of 74 years if more than three consecutive negative cytology reports have been confirmed within 10 years (recommendation D).

Lipid raft-dependent death receptor 5 (DR5) expression and activation are critical for ursodeoxycholic acid-induced apoptosis in gastric cancer cells

Ursodeoxycholic acid (UDCA) is known as a suppressor of cholestatic liver diseases and colorectal cancer development. Here, we demonstrate that UDCA induces apoptosis without necrotic features in SNU601, SNU638, SNU1 and SNU216 human gastric cancer cells, implying its possible use as an effective chemotherapeutic agent in treatment of gastric cancer. UDCA-induced apoptosis was dominantly mediated by an extrinsic pathway dependent on caspase-8, -6 and -3. UDCA increased expression of death receptor 5 [(DR5), also known as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2], and this DR appeared to be responsible for UDCA-induced apoptosis, as evidenced by DR5 knockdown. UDCA triggered formation of lipid rafts that played crucial roles in UDCA-induced apoptotic actions. Lipid rafts were required not only for provision of a proper site for DR5 action but also for mediation of DR5 expression. In addition, reactive oxygen species (ROS) and protein kinase C (PKC) δ appeared to be implicated in UDCA-induced raft-dependent DR5 expression. Our results indicate that UDCA-induced apoptosis is mediated by DR5 expression, which is regulated by the raft formation/ROS production/PKCδ activation pathway and DR5 localization into lipid rafts in gastric cancer cells. Tumor-suppressive activity of UDCA was confirmed in an in vivo system: UDCA (120 mg/kg/day) significantly decreased tumor growth in gastric cancer xenograft mice. Taken together, our results demonstrate that UDCA can be used as a potent chemotherapeutic agent for treatment of gastric cancer.

Colon cancer progression is driven by APEX1-mediated upregulation of Jagged

Aberrant expression of apurinic-apyrimidinic endonuclease-1 (APEX1) has been reported in numerous human solid tumors and is positively correlated with cancer progression; however, the role of APEX1 in tumor progression is poorly defined. Here, we show that APEX1 contributes to aggressive colon cancer behavior and functions as an upstream activator in the Jagged1/Notch signaling pathway. APEX1 overexpression or knockdown in human colon cancer cell lines induced profound changes in malignant properties such as cell proliferation, anchorage-independent growth, migration, invasion, and angiogenesis in vitro and in tumor formation and metastasis in mouse xenograft models. These oncogenic effects of APEX1 were mediated by the upregulation of Jagged1, a major Notch ligand. Furthermore, APEX1 expression was associated with Jagged1 in various colon cancer cell lines and in tissues from colon cancer patients. This finding identifies APEX1 as a positive regulator of Jagged1/Notch activity and suggests that it is a potential therapeutic target in colon cancers that exhibit high levels of Jagged1/Notch signaling.

Analysis of the healing process in sinus bone grafting using various grafting materials

OBJECTIVES

The purpose of this study was to compare differences in the healing process in the sinus bone grafting using various grafting materials.

STUDY DESIGN

Maxillary sinus bone grafts were divided into 4 groups according to the graft material used: group I, a mixture of autogenous bone and BioOss (Osteohealth Co., Shirley, NY); group II, a mixture of BioOss and Orthoblast II (Greencross; Isotis); group III, BioOss only; and group IV, synthetic bone, Osteon (Genoss, Korea), only. To evaluate the healing status of the graft surgery, bone specimens were collected from the lateral sinus using a 2.0-mm trephine bur at 4 and 6 months after surgery. Histology of the bone specimens was prepared, and the percentage of newly formed bone fraction, lamellar bone/woven bone ratio (LB/WB), and newly formed bone/graft material ratio (NB/GM) were measured to indicate the suitability of the materials and the healing of the grafts.

RESULTS

The LB/WB ratio and NB/GM ratio were markedly increased at 6 months compared with the values at 4 months. It was observed that good bone healing was achieved even for grafts of xenogeneic bone only or synthetic bone only. Cases grafted with a mixture of allogeneic and xenogeneic bone showed no great advantage regarding bone healing.

CONCLUSION

The results indicated that grafts of xenogeneic or synthetic bone can be effective for sinus bone grafting.

Essential Role of Polo-like Kinase 1 (Plk1) Oncogene in Tumor Growth and Metastasis of Tamoxifen-Resistant Breast Cancer

The most common therapy for estrogen receptor-positive breast cancer is antihormone therapy, such as tamoxifen. However, acquisition of resistance to tamoxifen in one third of patients presents a serious clinical problem. Polo-like kinase 1 (Plk1) is a key oncogenic regulator of completion of G2-M phase of the cell cycle. We assessed Plk1 expression in five chemoresistant cancer cell types and found that Plk1 and its downstream phosphatase Cdc25c were selectively overexpressed in tamoxifen-resistant MCF-7 (TAMR-MCF-7) breast cancer cells. Real-time monitoring of cell proliferation also showed that TAMR-MCF-7 cells were more sensitive to inhibition of cell proliferation by the ATP-competitive Plk1 inhibitor BI2536 than were the parent MCF-7 cells. Moreover, BI2536 suppressed expression of epithelial-mesenchymal transition marker proteins and 3D spheroid formation in TAMR-MCF-7 cells. Using TAMR-MCF-7 cell-implanted xenograft and spleen-liver metastasis models, we showed that BI2536 inhibited tumor growth and metastasis in vivo Our results suggest that Plk1 could be a novel target for the treatment of tamoxifen-resistant breast cancer. Mol Cancer Ther; 17(4); 825-37. ©2018 AACR.

A comparative study of two noninvasive techniques to evaluate implant stability: Periotest and Osstell Mentor

OBJECTIVES

The purpose of this study was to examine the usefulness of Periotest and Osstell Mentor (a resonance frequency analysis) as nondestructive analytical tools for determining implant stability in clinics, to evaluate the precision of both instruments, and to determine the applicability of these measured values as clinically relevant indices.

STUDY DESIGN

Four adult mongrel dogs weighing about 12 to 15 kg were used in this study. Bilateral extractions of the first through the fourth mandibular and maxillary premolars were performed and a total of 48 commercially pure titanium screw implants (USII Plus; OSTEM Implant, Seoul, Republic of Korea) were placed at 4 weeks after extraction. All implants (10 mm length and 3.3 mm diameter) were self-tapping and surface-treated with resorbable blast media (RBM). Periotest values (PTVs) obtained from Periotest, and Implant Stability Quotient (ISQ) obtained from Osstell Mentor, were measured at the time of implantation, and 3 and 6 weeks after implantation. At 3 and 6 weeks after implantation, 4 dogs were humanely killed and histomorphometric analysis was performed. The new peri-implant bone formation rate (NBFR) was measured.

RESULTS

The PTV value was lower and ISQ value was higher at 6 weeks when compared with data collected at 3 weeks after implantation. The PTVs of the maxilla were higher than the mandible and the ISQ values of the maxilla were lower than the mandible. Based on the NBFR, the 6-week group showed higher bone formation when compared to the 3-week group, correlating to the observed PTV and ISQ values. Additionally, the NBFR was higher in the maxilla than the mandible. No significant difference between PTV and ISQ was also observed when PTV and ISQ were compared to NBFR.

CONCLUSION

The results indicated that the Periotest and Osstell Mentor, both noninvasive diagnostic devices, were useful and comparably reliable, showing a strong association with each other in assessing implant stability.

Combined implantation of particulate dentine, plaster of Paris, and a bone xenograft (Bio-Oss) for bone regeneration in rats

The purpose of this study is to assess the combination of particulate dentine and plaster as bone substitute material in calvarial bone defects in rats, and to compare it with a bone xenograft (Bio-Oss).

MATERIAL AND METHODS

Forty rats were assigned randomly to five groups and each group was further divided into two subgroups, 8 and 16 weeks after implantation. The defect was filled with different graft materials in each group: Group 1, defects were filled with particulate dentine and plaster using a 2:1 ratio; Group 2, defects were filled with particulate dentine; plaster, and Bio-Oss using a 2:1:1 ratio; Group 3, defects were filled with plaster and Bio-Oss using a 1:1 ratio; Group 4, defects were filled with Bio-Oss only; and Group 5, untreated control defects. Histological sections and histomorphometric analysis of defects were obtained at 8 and 16 weeks postoperatively.

RESULTS

New bone formation was highest in Group 4, followed by Group 3, than Group 2, Group 1, and finally the control group.

CONCLUSION

The combination of particulate dentine and plaster is an alternative bone substitute, although it is less effective than Bio-Oss.