Overexpression of malic enzyme in the larval stage extends Drosophila lifespan.

Metabolic modifications during the developmental period can extend longevity. We found that malic enzyme (Men) overexpression during the larval period lengthened the lifespan of Drosophila. Men overexpression by S106-GeneSwitch-Gal4 driver increased pyruvate content and NADPH/NADP(+) ratio but reduced triglyceride, glycogen, and ATP levels in the larvae. ROS levels increased unexpectedly in Men-overexpressing larvae. Interestingly, adults exposed to larval Men-overexpression maintained ROS tolerance with enhanced expression levels of glutathione-S-transferase D2 and thioredoxin-2. Our results suggest that metabolic changes mediated by Men during development might be related to the control of ROS tolerance and the longevity of Drosophila.

Regulatory role of osteopontin in malignant transformation of endometrial cancer.

Osteopontin (OPN) involves in the tumor-promoting or metastasis in human endometrial cancer. Depletion of OPN gene expression in endometrial cancer cells was significantly decreased in cell viability and the cells undergo apoptotic cell death. The status of OPN in THESC, RL95, Hec1A and Ishikawa cell lines were analyzed by RT-PCR and western blot. After OPN-siRNA transfection, mRNA and protein expression levels of OPN were determined in Hec1A and Ishikawa cells. Cell proliferation and cell cycle distribution were observed by MTT and flow cytometry analysis. DNA fragmentation assay was used to measure cell apoptosis. Cell migration was assessed by wound healing assay. Depletion of OPN gene expression in endometrial cancer cell lines (Hec1A and Ishikawa cells) reproducibly changed their ability of proliferation. Concomitant changes were seen in the expression of OPN binding cell surface receptors, cell cycle-regulatory genes, cell invasion and colony formation nature of the tumor cells. Decreased colonizing potential in the absence of OPN was reversed in the presence of recombinant OPN. Inhibition of anchorage-independent growth was observed in the presence of metabolic inhibitors of the PI3K, Src and integrin signaling cascades, which was ameliorated in the presence of exogenously added OPN. Our result showed the role of OPN in endometrial cancer, in particular on the malignancy-promoting aspects of OPN that may pave way for new approaches to the clinical management of endometrial cancer.

Pattern of expression of cyclooxygenase-2 in malignant transformation of sinonasal inverted papilloma.

OBJECTIVE: Cyclooxygenases (COXs) are enzymes that catalyze the conversion of arachidonic acid to prostaglandins. Many studies have suggested that COX-2, the inducible form of COX, is important in carcinogenesis. However, little is known about the pattern of expression of COX-2 in a multistep process of malignant transformation of sinonasal inverted papilloma (IP). In this study, we investigated COX-2 expression in IPs, IPs with dysplasia, IPs with squamous cell carcinoma (SCC), and primary SCCs of sinonasal tract. STUDY DESIGN: A retrospective study was conducted. SETTING: The setting was a tertiary care referral center. SUBJECTS AND METHODS: The expression of COX-2 was evaluated by immunohistochemistry in 56, 7, 18, and 17 cases of IPs, IPs with dysplasia, IPs with SCC, and primary SCCs, respectively. Furthermore, we investigated the possible correlation between the expression of COX-2 and clinicopathologic variables in patients with IPs with SCC and primary SCC patients. RESULTS: Positive immunoreactivity for COX-2 was observed in 3 (5.4%) of 56 IPs, 7 (38.9%) of 18 IPs with SCC, and 7 (41.2%) of 17 primary SCCs, whereas it was not observed in IPs with dysplasia. The percentage of tumors with COX-2-positive immunostaining was significantly higher in IPs with SCC and primary SCCs compared with benign IPs. There was no significant correlation between the expression of COX-2 and clinicopathologic variables, such as tumor stage, histologic differentiation, and the proportion of malignant areas in patients with IPs with SCC. CONCLUSION: Cyclooxygenase-2 may play an important role in the process of malignant transformation from IP to SCC.

Prophylactic lymphadenectomy of neck level II in clinically node-positive papillary thyroid carcinoma.

BACKGROUND: The purpose of this study was to examine the frequency, pattern, and predictive factors associated with occult level II lymph node (LN) metastases in papillary thyroid carcinoma (PTC) patients with clinically metastatic lymph nodes in the lateral neck (level III, IV, and/or V) by preoperative ultrasonography. METHODS: We retrospectively reviewed the medical records of 52 PTC patients with clinically positive neck lymph nodes in level III, IV, and/or V based on preoperative ultrasonography, who underwent therapeutic lateral neck dissection (ND) (level II-V) between March 2004 and October 2009. All patients had no suspicion of clinically positive neck nodes in level II. Histopathological analysis of neck specimens according to each node level of the neck was performed, with special attention given to level II. RESULTS: Forty-two (81%), 41 (79%), and 6 (12%) patients had histologically positive lymph nodes in level III, IV, and V, respectively. Occult metastases in level II were observed in ten (19%) patients. Patients without suspicious positive LNs in both neck level III and IV by preoperative ultrasonography, and patients without pathologic LN metastases in level III, had no occult LN metastases occurrence to level II. Based on multivariate analysis, presence of more than four metastatic LNs was an independent predictive factor for occult level II metastases [P = 0.022, odds ratio (OR) = 7.738]. CONCLUSIONS: Prophylactic level II LN dissection may be omitted in PTC patients with clinically positive neck nodes if suspicious positive lymph nodes in level III are absent during preoperative ultrasonography.

Whole-exome and whole-transcriptome sequencing of canine mammary gland tumors.

Studies of naturally occurring cancers in dogs, which share many genetic and environmental factors with humans, provide valuable information as a comparative model for studying the mechanisms of human cancer pathogenesis. While individual and small-scale studies of canine cancers are underway, more generalized multi-omics studies have not been attempted due to the lack of large-scale and well-controlled genomic data. Here, we produced reliable whole-exome and whole-transcriptome sequencing data of 197 canine mammary cancers and their matched controls, annotated with rich clinical and biological features. Our dataset provides useful reference points for comparative analysis with human cancers and for developing novel diagnostic and therapeutic technologies for cancers in pet dogs.

A Therapeutic Strategy for Chemotherapy-Resistant Gastric Cancer via Destabilization of Both ß-Catenin and RAS.

: Treatment of advanced gastric cancer patients with current standard chemotherapeutic agents frequently results in resistance, leading to poor overall survival. However, there has been no success in developing strategies to overcome it. We showed the expression levels of both ß-catenin and RAS were significantly increased and correlated in tissues of 756 gastric cancer (GC) patients and tissues of primary- and acquired-resistance patient-derived xenograft tumors treated with 5-fluorouracil and oxaliplatin modulated with leucovorin (FOLFOX). On the basis of our previous studies, where small molecules to suppress colorectal cancer (CRC) via degrading both ß-catenin and RAS were developed, we tested the effectiveness of KYA1797K, a representative compound functioning by binding axin, in the growth of GC cells. The efficacy test of the drugs using gastric tumor organoids of Apc1638N mice showed that the CD44 and ALDH1A3 cancer stem cell markers were induced by FOLFOX, but not by KYA1797K. KYA1797K also efficiently suppressed tumors generated by re-engrafting the FOLFOX-resistant patient-derived xenograft (PDX) tumors, which also showed resistance to paclitaxel. Overall, the small-molecule approach degrading both ß-catenin and RAS has potential as a therapeutic strategy for treating GC patients resistant to current standard chemotherapies.

Establishment and characterisation of patient-derived xenografts as paraclinical models for gastric cancer.

The patient-derived xenograft (PDX) model is emerging as a promising translational platform to duplicate the characteristics of tumours. However, few studies have reported detailed histological and genomic analyses for model fidelity and for factors affecting successful model establishment of gastric cancer. Here, we generated PDX tumours surgically-derived from 62 gastric cancer patients. Fifteen PDX models were successfully established (24.2%, 15/62) and passaged to maintain tumours in immune-compromised mice. Diffuse type and low tumour cell percentage were negatively correlated with success rates (p = 0.005 and p = 0.025, respectively), while reducing ex vivo and overall procedure times were positively correlated with success rates (p = 0.003 and p = 0.01, respectively). The histology and genetic characteristics of PDX tumour models were stable over subsequent passages. Lymphoma transformation occurred in five cases (33.3%, 5/15), and all were in the NOG mouse, with none in the nude mouse. Together, the present study identified Lauren classification, tumour cell percentages, and ex vivo times along with overall procedure times, as key determinants for successful PDX engraftment. Furthermore, genetic and histological characteristics were highly consistent between primary and PDX tumours, which provide realistic paraclinical models, enabling personalised development of treatment options for gastric cancer.

Analysis of human embryonic stem cells with regulatable expression of the cell adhesion molecule l1 in regeneration after spinal cord injury.

Cell replacement therapy is one potential avenue for central nervous system (CNS) repair. However, transplanted stem cells may not contribute to long-term recovery of the damaged CNS unless they are engineered for functional advantage. To fine tune regenerative capabilities, we developed a human neural cell line expressing L1, a regeneration-conducive adhesion molecule, under the control of a doxycycline regulatable Tet-off promoter. Controlled expression of L1 is desired because overexpression after regenerative events may lead to adverse consequences. The regulated system was tested in several cell lines, where doxycycline completely eliminated green fluorescent protein or L1 expression by 3-5 days in vitro. Increased colony formation as well as decreased proliferation were observed in H9NSCs without doxycycline (hL1-on). To test the role of L1 in vivo after acute compression spinal cord injury of immunosuppressed mice, quantum dot labeled hL1-on or hL1-off cells were injected at three sites: lesion; proximal; and caudal. Mice transplanted with hL1-on cells showed a better Basso Mouse Scale score, when compared to those with hL1-off cells. As compared to the hL1-off versus hL1-on cell transplanted mice 6 weeks post-transplantation, expression levels of L1, migration of transplanted cells, and immunoreactivity for tyrosine hydroxylase were higher, whereas expression of chondroitin sulfate proteoglycans was lower. Results indicate that L1 expression is regulatable in human stem cells by doxycycline in a nonviral engineering approach. Regulatable expression in a prospective nonleaky Tet-off system could hold promise for therapy, based on the multifunctional roles of L1, including neuronal migration and survival, neuritogenesis, myelination, and synaptic plasticity.

Antitumor effects of flavopiridol on human uterine leiomyoma in vitro and in a xenograft model.

Dysregulated cyclin-dependent kinases (CDKs) are considered a potential target for cancer therapy. Flavopiridol is a potent CDK inhibitor. In this study, the antiproliferative effect of the flavonoid compound flavopiridol and its mechanism in human uterine leiomyoma cells were investigated. The present study focused on the effect of flavopiridol in cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. Cell viability and cell proliferation assays were conducted. Flow cytometry was performed to determine the effect of flavopiridol on cell cycle. The expression of cell cycle regulatory-related proteins was evaluated by Western blotting. Cell viability and proliferation of uterine leiomyoma cells were significantly reduced by flavopiridol treatment in a dose-dependent manner. Flow cytometry results showed that flavopiridol induced G1 phase arrest. Flavopiridol-induced growth inhibition in uterine leiomyoma cells was associated with increased expression of p21(cip/wafl) and p27(kip1) in a dose-dependent manner. Downregulation of CDK2/4 and Cyclin A with a concomitant increase in dephosphorylation of retinoblastoma was observed. This study demonstrates that flavopiridol inhibits cell proliferation by initiating G1 cell cycle arrest in human uterine leiomyoma. We also found that flavopiridol is effective in inhibiting xenografted human uterine leiomyoma growth. These results indicate that flavopiridol could prove to be a promising chemopreventive and therapeutic agent for human uterine leiomyoma.

Salinomycin inhibits Akt/NF-κB and induces apoptosis in cisplatin resistant ovarian cancer cells.

BACKGROUND: Despite advances in treatment, ovarian cancer is the most lethal gynecologic malignancy. Therefore significant efforts are being made to develop novel strategies for the treatment of ovarian cancer. Salinomycin has been shown to be highly effective in the elimination of cancer stem cells both in vitro and in vivo. The present study focused on investigating important cell signaling molecules such as Akt and NF-κB during salinomycin-induced apoptosis in cisplatin resistant ovarian cancer cells (A2780cis). METHODS: MTT assay was performed to determine cell viability. Flow cytometry and DNA fragmentation assay were performed to analyze the effect on cell cycle and apoptosis. The expression of apoptosis related proteins was evaluated by Western blot analysis. RESULTS: The cell viability was significantly reduced by salinomycin treatment in a dose dependent manner. The flow cytometry result showed an increase in sub-G1 phase. Salinomycin inhibited the nuclear transportation of NF-κB, and downregulated Akt expression. Declined Bcl-2, activation of caspase-3 and increased PARP cleavage triggered apoptosis. Moreover, DNA fragmentation assay also revealed apoptotic induction. CONCLUSION: The result suggested that salinomycin-induced apoptosis in A2780cis was associated with inhibition of Akt/NF-κB. It may become a potential chemotherapeutic agent for the cisplatin resistant ovarian cancer therapy.