Thiostrepton suppresses triple-negative breast cancer through downregulating c-FLIP/SMAD2/3 signaling pathway.

Triple-negative breast cancer (TNBC) is an aggressive subtype with poor prognosis of breast cancer. Thiostrepton exerts anti-tumor activities against several cancers including TNBC. Herein we discussed the new molecular mechanisms of thiostrepton in TNBC. Thiostrepton inhibited MDA-MB-231 cell viability, accompanied by a decrease of c-FLIP and p-SMAD2/3. c-FLIP overexpression reduced the sensitivity of MDA-MB-231 cells to thiostrepton, while SMAD2/3 knockdown increased the sensitivity of MDA-MB-231 cells to thiostrepton. Moreover, c-FLIP overexpression significantly increased the expression and phosphorylation of SMAD2/3 proteins and vice versa. In conclusion, our study reveals c-FLIP/SMAD2/3 signaling pathway as a novel mechanism of antitumor activity of thiostrepton.

Chromomycins from soil-derived Streptomyces sp. inhibit the growth of human non-small cell lung cancer cells by targeting c-FLIP.

Three chromomycin derivatives, chromomycins A3 (1, CA3), A5 (2, CA5), and monodeacetylchromomycin A3 (3, MDA-CA3), were identified from the soil-derived Streptomyces sp. CGMCC 26516. A reinvestigation of the structure of CA5 is reported, of which the absolute configuration was unambiguously determined for the first time to be identical with that of CA3 based on nuclear magnetic resonance (NMR) data analysis as well as NMR and electronic circular dichroism calculations. Compounds 1-3 showed potent cytotoxicity against the non-small-cell lung cancer (NSCLC) cells (A549, H460, H157-c-FLIP, and H157-LacZ) and down-regulated the protein expression of c-FLIP in A549 cells. The IC50 values of chromomycins in H157-c-FLIP were higher than that in H157-LacZ. Furthermore, si-c-FLIP promoted anti-proliferation effect of chromomycins in NSCLC cells. In nude mice xenograft model, 1 and 2 both showed more potent inhibition on the growth of H157-lacZ xenografts than that of H157-c-FLIP xenografts. These results verify that c-FLIP mediates the anticancer effects of chromomycins in NSCLC.

Skullcapflavone II, a novel NQO1 inhibitor, alleviates aristolochic acid I-induced liver and kidney injury in mice.

Aristolochic acid I (AAI) is a well established nephrotoxin and human carcinogen. Cytosolic NAD(P)H quinone oxidoreductase 1 (NQO1) plays an important role in the nitro reduction of aristolochic acids, leading to production of aristoloactam and AA-DNA adduct. Application of a potent NQO1 inhibitor dicoumarol is limited by its life-threatening side effect as an anticoagulant and the subsequent hemorrhagic complications. As traditional medicines containing AAI remain available in the market, novel NQO1 inhibitors are urgently needed to attenuate the toxicity of AAI exposure. In this study, we employed comprehensive 2D NQO1 biochromatography to screen candidate compounds that could bind with NQO1 protein. Four compounds, i.e., skullcapflavone II (SFII), oroxylin A, wogonin and tectochrysin were screened out from Scutellaria baicalensis. Among them, SFII was the most promising NQO1 inhibitor with a binding affinity (KD = 4.198 µmol/L) and inhibitory activity (IC50 = 2.87 µmol/L). In human normal liver cell line (L02) and human renal proximal tubular epithelial cell line (HK-2), SFII significantly alleviated AAI-induced DNA damage and apoptosis. In adult mice, oral administration of SFII dose-dependently ameliorated AAI-induced renal fibrosis and dysfunction. In infant mice, oral administration of SFII suppressed AAI-induced hepatocellular carcinoma initiation. Moreover, administration of SFII did not affect the coagulation function in short term in adult mice. In conclusion, SFII has been identified as a novel NQO1 inhibitor that might impede the risk of AAI to kidney and liver without obvious side effect.

Thymidine Kinase 1 Mediates the Synergistic Antitumor Activity of Ubenimex and Celecoxib via Regulation of Cell Cycle in Colorectal Cancer.

Colorectal cancer (CRC) is a common clinical malignant tumor of the digestive system that seriously affects the health and life of patients. Because it is difficult to cure CRC, the strategy of drug combination is often used in clinical therapy. This study mainly revealed that ubenimex and/or celecoxib exerted anti-colon cancer effects in vitro and in vivo, and the efficacy was significantly enhanced when the two drugs were combined. The combination of the two drugs induced significantly stronger cell-cycle arrest than did the single drug, and also enhanced the antitumor efficacy of 5-fluorouracil and its derivatives. At the same time, the expression of thymidine kinase 1 (TK1) protein was decreased through regulating the level of TK1 mRNA treated with celecoxib and/or ubenimex, but the combination drugs exhibited much more reduction of TK1 mRNA and protein as compared with the single agent alone. TK1 may be the molecular target of the combination of two drugs to exert the anti-colorectal cancer effect. In summary, this research demonstrates that celecoxib combined with ubenimex inhibits the development of colorectal cancer in vitro and in vivo, making them a viable combination regimen. SIGNIFICANCE STATEMENT: In this study, our data reveal the great potential of celecoxib combined with ubenimex in the treatment of colorectal cancer, providing new ideas for clinical antitumor drug regimens and theoretical reference for drug development.

c-FLIP promotes drug resistance in non-small-cell lung cancer cells via upregulating FoxM1 expression.

The forkhead box M1 (FoxM1) protein, a transcription factor, plays critical roles in regulating tumor growth and drug resistance, while cellular FLICE-inhibitory protein (c-FLIP), an anti-apoptotic regulator, is involved in the ubiquitin-proteasome pathway. In this study, we investigated the effects of c-FLIP on the expression and ubiquitination levels of FoxM1 along with drug susceptibility in non-small-cell lung cancer (NSCLC) cells. We first showed that the expression levels of FoxM1 and c-FLIP were increased and positively correlated (R2 = 0.1106, P < 0.0001) in 90 NSCLC samples. The survival data from prognostic analysis demonstrated that high expression of c-FLIP and/or FoxM1 was related to poor prognosis in NSCLC patients and that the combination of FoxM1 and c-FLIP could be a more precise prognostic biomarker than either alone. Then, we explored the functions of c-FLIP/FoxM1 in drug resistance in NSCLC cell lines and a xenograft mouse model in vivo. We showed that c-FLIP stabilized FoxM1 by inhibiting its ubiquitination, thus upregulated the expression of FoxM1 at post-transcriptional level. In addition, a positive feedback loop composed of FoxM1, ß-catenin and p65 also participated in c-FLIP-FoxM1 axis. We revealed that c-FLIP promoted the resistance of NSCLC cells to thiostrepton and osimertinib by upregulating FoxM1. Taken together, these results reveal a new mechanism by which c-FLIP regulates FoxM1 and the function of this interaction in the development of thiostrepton and osimertinib resistance. This study provides experimental evidence for the potential therapeutic benefit of targeting the c-FLIP-FoxM1 axis for lung cancer treatment.

The necessity of transperineal ultrasound view in urethra malacoplakia.

This case illustrates the untypical presentation of primary bladder malacoplakia. The patient was in her mid-50s have impaired immunity by the long-term hyperglycemic condition. She presented with symptoms of urinary tract infection and dysuria, and had multiple nodulars in bladder and significantly mass in urethra. Although the diagnosis of bladder malacoplakia was established on bladder biopsy, transperineal ultrasound examination can find its distinct clinical presentation.

Honokiol inhibits breast cancer cell metastasis by blocking EMT through modulation of Snail/Slug protein translation.

Honokiol (HNK), an active compound isolated from traditional Chinese medicine Magnolia officinalis, has shown potent anticancer activities. In the present study, we investigated the effects of HNK on breast cancer metastasis in vitro and in vivo, as well as the underlying molecular mechanisms. We showed that HNK (10-70 µmol/L) dose-dependently inhibited the viability of human mammary epithelial tumor cell lines MCF7, MDA-MB-231, and mouse mammary tumor cell line 4T1. In the transwell and scratch migration assays, HNK (10, 20, 30 µmol/L) dose-dependently suppressed the invasion and migration of the breast cancer cells. We demonstrated that HNK (10-50 µmol/L) dose-dependently upregulated the epithelial marker E-cadherin and downregulated the mesenchymal markers such as Snail, Slug, and vimentin at the protein level in breast cancer cells. Using a puromycin incorporation assay, we showed that HNK decreased the Snail translation efficiency in the breast cancer cells. In a mouse model of tumor metastasis, administration of HNK (50 mg/kg every day, intraperitoneal (i.p.), 6 times per week for 30 days) significantly decreased the number of metastatic 4T1 cell-derived nodules and ameliorated the histological alterations in the lungs. In addition, HNK-treated mice showed decreased Snail expression and increased E-cadherin expression in metastatic nodules. In conclusion, HNK inhibits EMT in the breast cancer cells by downregulating Snail and Slug protein expression at the mRNA translation level. HNK has potential as an integrative medicine for combating breast cancer by targeting EMT.

Chronic inflammation-elicited liver progenitor cell conversion to liver cancer stem cell with clinical significance.

The substantial heterogeneity and hierarchical organization in liver cancer support the theory of liver cancer stem cells (LCSCs). However, the relationship between chronic hepatic inflammation and LCSC generation remains obscure. Here, we observed a close correlation between aggravated inflammation and liver progenitor cell (LPC) propagation in the cirrhotic liver of rats exposed to diethylnitrosamine. LPCs isolated from the rat cirrhotic liver initiated subcutaneous liver cancers in nonobese diabetic/severe combined immunodeficient mice, suggesting the malignant transformation of LPCs toward LCSCs. Interestingly, depletion of Kupffer cells in vivo attenuated the LCSC properties of transformed LPCs and suppressed cytokeratin 19/Oval cell 6-positive tumor occurrence. Conversely, LPCs cocultured with macrophages exhibited enhanced LCSC properties. We further demonstrated that macrophage-secreted tumor necrosis factor-α triggered chromosomal instability in LPCs through the deregulation of ubiquitin D and checkpoint kinase 2 and enhanced the self-renewal of LPCs through the tumor necrosis factor receptor 1/Src/signal transducer and activator of transcription 3 pathway, which synergistically contributed to the conversion of LPCs to LCSCs. Clinical investigation revealed that cytokeratin 19/Oval cell 6-positive liver cancer patients displayed a worse prognosis and exhibited superior response to sorafenib treatment. CONCLUSION: Our results not only clarify the cellular and molecular mechanisms underlying the inflammation-mediated LCSC generation but also provide a molecular classification for the individualized treatment of liver cancer. (Hepatology 2017;66:1934-1951).

RGD and NGR modified TRAIL protein exhibited potent anti-metastasis effects on TRAIL-insensitive cancer cells in vitro and in vivo.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been considered to be a promising anti-tumor agent since the discovery of TRAIL-mediated apoptosis specifically on cancer cells. However, TRAIL resistance of tumor cells and patients remains to be an insurmountable obstacle for its clinical application. Here, we expressed TRAIL-related recombinant protein RGD-TRAIL, TRAIL-NGR, and RGD-TRAIL-NGR by fusing tumor targeting peptides RGD and (or) NGR at the N-terminus and C-terminus, respectively, to not only induce apoptosis of cancer cells but also inhibit metastasis. The fusion proteins possessed potent cytotoxicity with approximative IC50 in H460 and A549 cells, while TRAIL-NGR and RGD-TRAIL-NGR appeared to be more effective in HT1080 and PANC-1 cells which were relatively insensitive to TRAIL. A low concentration of fusion proteins, especially RGD-TRAIL-NGR, could inhibit migration of A549 and HT1080 cells in vitro and lung metastasis in HT1080LUC experimental model in vivo, indicating that the recombinant protein maintained the function of both TRAIL and targeting peptide RGD and NGR, which improved the sensitivity of tumor cells to TRAIL.

Honokiol inhibits EMT-mediated motility and migration of human non-small cell lung cancer cells in vitro by targeting c-FLIP.

AIM: Honokiol (HNK) is a natural compound isolated from the magnolia plant with numerous pharmacological activities, including inhibiting epithelial-mesenchymal transition (EMT), which has been proposed as an attractive target for anti-tumor drugs to prevent tumor migration. In this study we investigated the effects of HNK on EMT in human NSCLC cells in vitro and the related signaling mechanisms. METHODS: TNF-α (25 ng/mL) in combination with TGF-ß1 (5 ng/mL) was used to stimulate EMT of human NSCLC A549 and H460 cells. Cell proliferation was analyzed using a sulforhodamine B assay. A wound-healing assay and a transwell assay were performed to examine cell motility. Western blotting was used to detect the expression levels of relevant proteins. siRNAs were used to knock down the gene expression of c-FLIP and N-cadherin. Stable overexpression of c-FLIP L (H157-FLIP L) or Lac Z (H157-Lac Z) was also performed. RESULTS: Treatment with TNF-α+TGF-ß1 significantly enhanced the migration of A549 and H460 cells, increased c-FLIP, N-cadherin (a mesenchymal marker), snail (a transcriptional modulator) and p-Smad2/3 expression, and decreased IκB levels in the cells; these changes were abrogated by co-treatment with HNK (30 µmol/L). Further studies demonstrated that expression level of c-FLIP was highly correlated with the movement and migration of NSCLC cells, and the downstream effectors of c-FLIP signaling were NF-κB signaling and N-cadherin/snail signaling, while Smad signaling might lie upstream of c-FLIP. CONCLUSION: HNK inhibits EMT-mediated motility and migration of human NSCLC cells in vitro by targeting c-FLIP, which can be utilized as a promising target for cancer therapy, while HNK may become a potential anti-metastasis drug or lead compound.

[Research progress in anticancer effects and molecular targets of honokiol in experimental therapy].

Honokiol(HNK), one of major biological active constituents of Mangnolia officinalis, exerts a wide range of biological functions, such as moderate anticancer effects. It inhibits the growth of lung cancer, gastrointestinal cancer, head and neck squamous cell carcinoma, breast cancer, prostate cancer, ovarian cancer, in vitro and in vivo through multiple potential molecular targets. It modulates apoptosis-associated signaling pathway, inhibits growth factor receptor-mediated signal transduction pathway, blocks nuclear factor-κB signaling pathway, decreases the expression level of androgen receptors, subsides m TOR and STAT3 signaling pathway, and so on. HNK enhances the inhibitory effects of traditional anticancer drugs or targeted antitumor drugs in vitro and in vivo. It reverses multidrug resistances of cancer cells to cisplatin, doxorubicin and paclitaxol. Therefore, HNK plays a role in the augmentation of antitumor effects of cancer drugs and the reversal of multidrug resistance of tumor cells. HNK is a promising biochemical modulator of anti-cancer medicines in the cancer therapy.

A bispecific fusion protein and a bifunctional enediyne-energized fusion protein consisting of TRAIL, EGFR peptide ligand, and apoprotein of lidamycin against EGFR and DR4/5 show potent antitumor activity.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mainly induces apoptosis through the extrinsic death receptor-induced pathway by ligation with death receptor 4 (DR4) and death receptor 5 (DR5). On the basis of the antitumor activity to cancer cells and no cytotoxity to normal cells of TRAIL and the target of the epidermal growth factor receptor (EGFR) ligand peptide, the study constructed a new bispecific fusion protein and a new bifunctional enediyne-energized fusion protein and investigated their antitumor efficacy. Bispecific fusion protein Ec-LDP-TRAIL showed potent binding activity to cancer cell lines with a high expression of EGFR or DR4/DR5 such as A431 and H460 cells, whereas poor binding activity to NIH/3T3 cells with low expressing EGFR and DR4/DR5. Ec-LDP-TRAIL also showed more potent cytotoxicity to A431 and H460 cells than Ec-LDP, which could result from the TRAIL-inducing apoptosis. Results of an in-vivo efficacy study showed that Ec-LDP-TRAIL at a dose of 10 mg/kg decreased the growth of epidermoid carcinoma A431 xenografts by 80.19% (P < 0.01) on day 26. Immunohistochemical detection of nuclear antigen factor Ki-67 suggested that Ec-LDP-TRAIL effectively induced cell necrosis and inhibited cell proliferation of tumor. From IC50 values, bispecific and bifunctional energized fusion protein Ec-LDP-TRAIL-AE was more potent and selective in its cytotoxicity against different carcinoma cell lines than corresponding lidamycin in vitro and induction of the cleavage of poly(ADP-ribose)polymerase was observed in A431 cells treated with Ec-LDP-TRAIL-AE and lidamycin, respectively. Ec-LDP-TRAIL-AE also significantly inhibited the growth of A431 xenografts in a nude mouse model. These properties suggested that Ec-LDP-TRAIL and Ec-LDP-TRAIL-AE may be promising candidates for targeted cancer therapy.

[Expression and antitumor activity of fusion protein RGD-TRAIL in Pichia pastoris].

To compare the activity of RGD-TRAIL in different expression systems, RGD-TRAIL in both Escherichia coli (E.coli) and Pichia pastoris was constructed and expressed. In vitro activity of RGD-TRAIL from Pichia pastoris expression system was also analyzed. Genetic engineering techniques were used to construct recombinant plasmid pET30-rgd-trail and pHBM-rgd-trail. The recombinant protein RGD-TRAIL was purified with Ni ion affinity chromatography after induction. MTT assay, ELISA, scratch wound healing, transwell migration assay and Hoechst 33342 staining were performed to detect the effects of RGD-TRAIL on proliferation, binding activity, migration and apoptosis. The expression of apoptosis-associated proteins was detected by Western blotting. Recombinant protein RGD-TRAIL was successfully expressed in a form of inclusion body in E.coli, while expressed secretorily in Pichia pastoris. It possessed more potent cytotoxicity than RGD-TRAIL in E.coli by MTT assay. The RGD-TRAIL expressed by Pichia pastoris showed powerful binding affinity with cancer cells expressing α(v), DR4, DR5 and highly potent cytotoxicity through inducing apoptosis of cancer cells. Nuclear fragmentation was examined by Hoechst 33342 staining. Cleaved PARP and caspase-3 were also detected after incubation with RGD-TRAIL. Additionally, RGD-TRAIL inhibited migration significantly in A549 and HT1080 cells. The results demonstrate that Pichia pastoris expression system is more suitable for the recombinant protein RGD-TRAIL. Its binding affinity and antitumor activity might make RGD-TRAIL a promising candidate for cancer therapy.

[Nursing care of chemotherapy-induced peripheral neuropathy].

Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse event occurring in patients who receive neurotoxic chemotherapeutic agents such as taxanes, platinum, and vinca alkaloids. The manifestations of CIPN include intolerable symmetric numbness, burning and tingling in distal limbs, disruption of daily functions, reduced quality of life, and the reduction in dosage or discontinued use of these agents. There is a paucity of articles on nursing care related to CIPN in the literature. This article reviews the pathophysiology, clinical presentation, diagnostic criteria, medical management and nursing care of CIPN. Review findings are intended to help nurses identify high-risk groups in order to implement preventive measures that strengthen the muscles, train the balance, and initiate falling precautions of persons in this population. Timely preventive measures may effectively alleviate CIPN symptoms and assure the safety and overall quality of life of patients.

Chloroquine potentiates the anti-cancer effect of lidamycin on non-small cell lung cancer cells in vitro.

AIM: To assess the synergistic actions of lidamycin (LDM) and chloroquine (CQ), a lysosomal enzyme inhibitor, in human non-small cell lung cancer (NSCLC) cells, and to elucidate the potential mechanisms. METHODS: Human NSCLC cell lines A549 and H460 were treated with CQ and/or LDM. Cell proliferation was analyzed using MTT assay, and apoptosis was quantified using flow cytometry. Western blotting was used to detect the protein levels of caspase 3, PARP, Bcl-2, Bax, p53, LC3-I and LC3-II. A H460 cell xenograft model in BALB/c nude mice was used to evaluate the anticancer efficacy of CQ and LDM in vivo. RESULTS: Both LDM and CQ concentration-dependently suppressed the proliferation of A549 and H460 cells in vitro (the IC50 values of LDM were 1.70 ± 0.75 and 0.043 ± 0.026 nmol/L, respectively, while the IC50 values of CQ were 71.3 ± 6.1 and 55.6 ± 12.5 µmol/L, respectively). CQ sensitized both NSCLC cell lines to LDM, and the majority of the coefficients of drug interaction (CDIs) for combination-doses were less than 1. The ratio of apoptosis of H460 cells induced by a combined treatment of CQ and LDM (77.0% ± 5.2%) was significantly higher than those caused by CQ (23.1% ± 4.2%) or by LDM (65.1% ± 4.1%) alone. Furthermore, the combined treatment markedly increased the cleaved PARP and cleaved caspase 3 in H460 cells, which were partly reversed by pretreatment with the caspase inhibitor zVAD.fmk. zVAD.fmk also partially reversed the inhibitory effect of the combination treatment on the proliferation of H460 cells. The combination therapy group had a notable increase in expression of Bax and a very slight decrease in expression of Bcl-2 and p53 protein. LDM alone scarcely affected the level of LC3-II in H460 cells, but slightly reduced CQ-induced LC3-II expression. 3-MA, an autophagy inhibitor also sensitized H460 cells to LDM. In nude mice bearing H460 cell xenograft, administration of LDM (25 µg/kg, iv) and CQ (60 mg/kg, ip) suppressed tumor growth by 57.14% and 73.02%, respectively. CONCLUSION: The synergistic anticancer effect of LDM and CQ in vitro results from activation of a caspase-dependent and p53-independent apoptosis pathway as well as inhibition of cytoprotective autophagy.

Therapeutic effects of mesenchymal stem cell-derived microvesicles on pulmonary arterial hypertension in rats.

AIM: Microvesicles (MVs) are nanoscale membrane fragments released from virtually all cell types upon activation or apoptosis, and may contribute to the beneficial effects of stem cell therapy. In this study, we investigated the therapeutic effects of mesenchymal stem cell (MSC) derived MVs (MSC-MVs) on pulmonary artery hypertension (PAH) in rats. METHODS: MSC-MVs were isolated from rat bone marrow MSCs that were cultured in a serum-free conditioned medium. Transmission electron microscopy (TEM), flow cytometry and nanoparticle tracking analysis (NTA) were used to characterize the MVs. Adult SD rats were injected with monocrotaline (50 mg/kg, sc) to induce PAH. Three weeks later, the rats were intravenously injected with MSCs, MSC-MVs or saline for 2 weeks. At the end of treatments, the hemodynamic parameters and pathological right ventricular and pulmonary arterial remodeling were analyzed in each group. RESULTS: The MSC-MVs showed general morphologic characteristics of MVs and expressed annexin V and CD29 markers under TEM, and their size ranged from 40 to 300 nm. Intravenous injection of MSC-MVs or MSCs significantly ameliorated the mean pulmonary artery pressure (mPAP) and mean right ventricle pressure (mRVP) in PAH rats. Furthermore, intravenous injection of MSC-MVs or MSCs significantly decreased the right ventricle (RV) hypertrophy and pulmonary arteriole area index (AI) and thickness index (TI) in PAH rats. CONCLUSION: Intravenous injection of MSC-MVs or MSCs produces similar beneficial effects for treating PAH, and our results provide a basis for cell-free approach in stem cell therapy.

[Molecular targets of tea polyphenols and its roles of anticancer drugs in experimental therapy].

Tea polyphenols (TPs), major biological active constituents of green tea, exert moderate and selective anticancer effects. Molecular mechanisms of TPs in cancer prevention and treatment involve multiple potential molecular targets. TPs inhibit growth factor receptor-mediated signal transduction pathway, decrease the activities of mitogen activated protein kinases and activator protein transcription factor-1, block nuclear factor-kappaB signaling pathway, reduce proteasome activity, lower overexpression of COX-2, subside dihydrofolate reductase and telomerase, and inhibit DNA methylation and matrix metalloproteinases. Furthermore, TPs enhance the inhibitory effect on the growth of cancers by traditional anticancer drugs or targeted antitumor drugs in vitro and in vivo and reverse multidrug resistances of cancer cells to vincristine, doxorubicin, and 5-fluorouracil. Besides, TPs reduce the nephrotoxicity induced by cisplatin, ameliorate irinotecan-induced side effects in the small intestine of mice, and decrease bleomycin-caused DNA damage in human leukocytes. TPs also increase antitumor activity of vaccine through immunological modulation. TPs play roles of the augmentation of antitumor effects, the reversal of multidrug resistance, and the reduction of side effects of chemotherapeutic drugs. TPs could be used as biochemical modulators in cancer therapy.

FASN Inhibitors Enhance Bestatin-Related Tumor Cell Apoptosis Through Upregulating PEPT1.

BACKGROUND: Fatty acid synthase (FASN) is generally over-expressed in human tumor tissues and catalyzes de novo synthesis of fatty acids on which tumor cells depend. Bestatin, an inhibitor of aminopeptidase/CD13, is one of the dipeptide substrates for the human oligopeptide transporter 1 (PEPT1). OBJECTIVES: In the current study, we aimed to uncover the role of FASN inhibitors in bestatininduced tumor cell apoptosis and the underlying mechanism, extending our understanding of the correlations between FASN and PEPT1 in cancer and providing a new strategy for tumor targeted treatment. METHODS: Cerulenin, orlistat and siRNAs were applied to inhibit FASN. The cell viability and apoptosis were assessed with MTT (thiazolyl blue tetrazolium bromide) assays and annexin VFITC/ PI staining with flow cytometry analysis. Western blot and qRT-PCR analysis were used to detect the protein levels and mRNA levels of the indicated genes in tumor cells, respectively. Protein degradation or stability was examined with cycloheximide chase assays. CD13 activity was detected by gelatin zymography. The HT1080 and C26 xenografts models were conducted to assess the efficacy in vivo. RESULTS: In the current study, we found that inhibiting FASN by cerulenin and orlistat both augmented the effects of bestatin in decreasing tumor cell viability. Cerulenin increased the apoptosis rates and enhanced the cleavage of PARP caused by bestatin. Furthermore, cerulenin, orlistat and siFASNs markedly elevated PEPT1 protein levels. Indeed, cerulenin induced the upregulation of PEPT1 mRNA expression rather than affecting the protein level after the cells were treated with CHX. And Gly-Sar, a typical competitive substrate of PEPT1, could attenuate the augment of bestatin-induced cell killing by cerulenin. Moreover, synergistic restrain of tumor growth accompanied by a reduction of Ki-67 and increment of TUNEL was significantly achieved in the xenograft models. Interestingly, no clear correlation was observed between the CD13 with FASN and/or PEPT1 in tumor cells. CONCLUSION: FASN inhibitors facilitate tumor cells susceptible to bestatin-induced apoptosis involving the up-regulation of PEPT1 at the mRNA translation level and the transport of bestatin by PEPT1, emerging as a promising strategy for tumor targeted therapy.

Brown adipocytes promote epithelial mesenchymal transition of neuroblastoma cells by inducing PPAR-γ/UCP2 expression.

Neuroblastoma (NB) is an embryonic malignant tumour of the sympathetic nervous system, and current research shows that activation of brown adipose tissue accelerates cachexia in cancer patients. However, the interaction between brown adipose tissues and NB remains unclear. The study aimed to investigate the effect of brown adipocytes in the co-culture system on the proliferation and migration of NB cells. Brown adipocytes promoted the proliferation and migration of Neuro-2a, BE(2)-M17, and SH-SY5Y cells under the co-culture system, with an increase of the mRNA and protein levels of UCP2 and PPAR-γ in NB cells. The UCP2 inhibitor genipin or PPAR-γ inhibitor T0090709 inhibited the migration of NB cells induced by brown adipocytes. Genipin or siUCP2 upregulated the expression of E-cadherin, and downregulated the expression of N-cadherin and vimentin in NB cells. We suggest that under co-cultivation conditions, NB cells can activate brown adipocytes, which triggers changes in various genes and promotes the proliferation and migration of NB cells. The PPAR-γ/UCP2 pathway is involved in the migration of NB cells caused by brown adipocytes.