Targeting STAT3 by HO3867 induces apoptosis in ovarian clear cell carcinoma.

Advanced ovarian clear cell carcinoma (OCCC) carries a very poor prognosis in large part secondary to the extremely high rate of resistance to standard platinum and taxane chemotherapy. Signal transducer and activator of transcription 3(STAT3) expression and activation has been shown to regulate tumor progression in various human cancers, though has not been well studied in OCCC. Preliminary work in our lab has demonstrated constitutive activation of STAT3 (pSTAT3Tyr705 or pSTAT3727) in OCCC cell lines as well as human OCCC tumor tissue samples. Significantly, pSTAT3 is expressed in the absence of other forms of activated STAT (pSTAT1, 2, 6). Therefore, this work was planned to investigate the role of STAT3 and examine the efficacy of a novel anti-cancer compound -HO-3867, which is an inhibitor of STAT3, using known OCCC cell lines. Results demonstrate that treatment with HO-3867 decreased expression of pSTAT3 Tyr705 as well pSTAT3 Ser727, while total STAT3 remained constant. STAT3 overexpression increased the migration capability in OVTOKO cells in vitro and led to an increased tumor size when injected in vivo. The inhibitory effect of HO-3867 on cell proliferation and cell survival was accompanied by increased apoptosis, within 24 h post treatment. Treatment with HO-3867 resulted in a decrease in Bcl-2 and increase of cleavage of caspase 3, caspase 7, and PARP, confirming induction of apoptosis after treatment with HO-3867. In addition, HO-3867 significantly inhibited formation of human umbilical vein endothelial cells capillary-like structures and invasion at both 5 and 10 µM concentrations. STAT3 expression plays an important role in the spread of OCCC in vitro as well as in vivo. Thus, we can exploit the STAT3 pathway for targeted drug therapy. Inhibition of pSTAT3 using HO-3867in OCCC cell lines appears to be a promising therapy. This is of utmost importance given the poor response of OCCC to standard chemotherapy regimens.

A novel small molecular STAT3 inhibitor, LY5, inhibits cell viability, cell migration, and angiogenesis in medulloblastoma cells.

Signal transducers and activators of transcription 3 (STAT3) signaling is persistently activated and could contribute to tumorigenesis of medulloblastoma. Numerous studies have demonstrated that inhibition of the persistent STAT3 signaling pathway results in decreased proliferation and increased apoptosis in human cancer cells, indicating that STAT3 is a viable molecular target for cancer therapy. In this study, we investigated a novel non-peptide, cell-permeable small molecule, named LY5, to target STAT3 in medulloblastoma cells. LY5 inhibited persistent STAT3 phosphorylation and induced apoptosis in human medulloblastoma cell lines expressing constitutive STAT3 phosphorylation. The inhibition of STAT3 signaling by LY5 was confirmed by down-regulating the expression of the downstream targets of STAT3, including cyclin D1, bcl-XL, survivin, and micro-RNA-21. LY5 also inhibited the induction of STAT3 phosphorylation by interleukin-6 (IL-6), insulin-like growth factor (IGF)-1, IGF-2, and leukemia inhibitory factor in medulloblastoma cells, but did not inhibit STAT1 and STAT5 phosphorylation stimulated by interferon-γ (IFN-γ) and EGF, respectively. In addition, LY5 blocked the STAT3 nuclear localization induced by IL-6, but did not block STAT1 and STAT5 nuclear translocation mediated by IFN-γ and EGF, respectively. A combination of LY5 with cisplatin or x-ray radiation also showed more potent effects than single treatment alone in the inhibition of cell viability in human medulloblastoma cells. Furthermore, LY5 demonstrated a potent inhibitory activity on cell migration and angiogenesis. Taken together, these findings indicate LY5 inhibits persistent and inducible STAT3 phosphorylation and suggest that LY5 is a promising therapeutic drug candidate for medulloblastoma by inhibiting persistent STAT3 signaling.

p53/TAp63 and AKT regulate mammalian target of rapamycin complex 1 (mTORC1) signaling through two independent parallel pathways in the presence of DNA damage.

Under conditions of DNA damage, the mammalian target of rapamycin complex 1 (mTORC1) is inhibited, preventing cell cycle progression and conserving cellular energy by suppressing translation. We show that suppression of mTORC1 signaling to 4E-BP1 requires the coordinated activity of two tumor suppressors, p53 and p63. In contrast, suppression of S6K1 and ribosomal protein S6 phosphorylation by DNA damage is Akt-dependent. We find that loss of either p53, required for the induction of Sestrin 1/2, or p63, required for the induction of REDD1 and activation of the tuberous sclerosis complex, prevents the DNA damage-induced suppression of mTORC1 signaling. These data indicate that the negative regulation of cap-dependent translation by mTORC1 inhibition subsequent to DNA damage is abrogated in most human cancers.

Reciprocal regulation of microRNA-122 and c-Myc in hepatocellular cancer: role of E2F1 and transcription factor dimerization partner 2.

UNLABELLED: c-Myc is a well-known oncogene frequently up-regulated in different malignancies, whereas liver-specific microRNA (miR)-122, a bona fide tumor suppressor, is down-regulated in hepatocellular cancer (HCC). Here we explored the underlying mechanism of reciprocal regulation of these two genes. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and northern blot analysis demonstrated reduced expression of the primary, precursor, and mature miR-122 in c-MYC-induced HCCs compared to the benign livers, indicating transcriptional suppression of miR-122 upon MYC overexpression. Indeed, chromatin immunoprecipitation (ChIP) assay showed significantly reduced association of RNA polymerase II and histone H3K9Ac, markers of active chromatin, with the miR-122 promoter in tumors relative to the c-MYC-uninduced livers, indicating transcriptional repression of miR-122 in c-MYC-overexpressing tumors. The ChIP assay also demonstrated a significant increase in c-Myc association with the miR-122 promoter region that harbors a conserved noncanonical c-Myc binding site in tumors compared to the livers. Ectopic expression and knockdown studies showed that c-Myc indeed suppresses expression of primary and mature miR-122 in hepatic cells. Additionally, Hnf-3ß, a liver enriched transcription factor that activates miR-122 gene, was suppressed in c-MYC-induced tumors. Notably, miR-122 also repressed c-Myc transcription by targeting transcriptional activator E2f1 and coactivator Tfdp2, as evident from ectopic expression and knockdown studies and luciferase reporter assays in mouse and human hepatic cells. CONCLUSION: c-Myc represses miR-122 gene expression by associating with its promoter and by down-regulating Hnf-3ß expression, whereas miR-122 indirectly inhibits c-Myc transcription by targeting Tfdp2 and E2f1. In essence, these results suggest a double-negative feedback loop between a tumor suppressor (miR-122) and an oncogene (c-Myc).

Hepatic loss of miR-122 predisposes mice to hepatobiliary cyst and hepatocellular carcinoma upon diethylnitrosamine exposure.

Loss of miR-122 causes chronic steatohepatitis and spontaneous hepatocellular carcinoma. However, the consequence of miR-122 deficiency on genotoxic stress-induced liver pathogenesis is poorly understood. Here, we investigated the impact of miR-122 depletion on liver pathobiology by treating liver-specific miR-122 knockout (LKO) mice with the hepatocarcinogen diethylnitrosamine (DEN). At 25 weeks post-DEN injection, all LKO mice developed CK-19-positive hepatobiliary cysts, which correlated with DEN-induced transcriptional activation of Cdc25a mediated through E2f1. Additionally, LKO livers were more fibrotic and vascular, and developed larger microscopic tumors, possibly due to elevation of the Axl oncogene, a receptor tyrosine kinase as a novel target of miR-122, and several protumorigenic miR-122 targets. At 35 weeks following DEN exposure, LKO mice exhibited a higher incidence of macroscopic liver tumors (71%) and cysts (86%) compared to a 21.4% and 0% incidence of tumors and cysts, respectively, in control mice. The tumors in LKO mice were bigger (ninefold, P = 0.015) and predominantly hepatocellular carcinoma, whereas control mice mostly developed hepatocellular adenoma. DEN treatment also reduced survival of LKO mice compared to control mice (P = 0.03). Interestingly, induction of oxidative stress and proinflammatory cytokines in LKO liver shortly after DEN exposure indicates predisposition of a pro-tumorigenic microenvironment. Collectively, miR-122 depletion facilitates cystogenesis and hepatocarcinogenesis in mice on DEN challenge by up-regulating several genes involved in proliferation, growth factor signaling, neovascularization, and metastasis.

Treatment of medulloblastoma with oncolytic measles viruses expressing the angiogenesis inhibitors endostatin and angiostatin.

BACKGROUND: Medulloblastoma is the most common type of pediatric brain tumor. Although numerous factors influence patient survival rates, more than 30% of all cases will ultimately be refractory to conventional therapies. Current standards of care are also associated with significant morbidities, giving impetus for the development of new treatments. We have previously shown that oncolytic measles virotherapy is effective against medulloblastoma, leading to significant prolongation of survival and even cures in mouse xenograft models of localized and metastatic disease. Because medulloblastomas are known to be highly vascularized tumors, we reasoned that the addition of angiogenesis inhibitors could further enhance the efficacy of oncolytic measles virotherapy. Toward this end, we have engineered an oncolytic measles virus that express a fusion protein of endostatin and angiostatin, two endogenous and potent inhibitors of angiogenesis. METHODS: Oncolytic measles viruses encoding human and mouse variants of a secretable endostatin/angiostatin fusion protein were designed and rescued according to established protocols. These viruses, known as MV-hE:A and MV-mE:A respectively, were then evaluated for their anti-angiogenic potential and efficacy against medulloblastoma cell lines and orthotopic mouse models of localized disease. RESULTS: Medulloblastoma cells infected by MV-E:A readily secrete endostatin and angiostatin prior to lysis. The inclusion of the endostatin/angiostatin gene did not negatively impact the measles virus' cytotoxicity against medulloblastoma cells or alter its growth kinetics. Conditioned media obtained from these infected cells was capable of inhibiting multiple angiogenic factors in vitro, significantly reducing endothelial cell tube formation, viability and migration compared to conditioned media derived from cells infected by a control measles virus. Mice that were given a single intratumoral injection of MV-E:A likewise showed reduced numbers of tumor-associated blood vessels and a trend for increased survival compared to mice treated with the control virus. CONCLUSIONS: These data suggest that oncolytic measles viruses encoding anti-angiogenic proteins may have therapeutic benefit against medulloblastoma and support ongoing efforts to target angiogenesis in medulloblastoma.

Detection and biological activities of carboxyethylpyrrole ethanolamine phospholipids (CEP-EPs).

Oxidation of docosahexaenoate phospholipids produces 4-hydroxy-7-oxo-hept-5-eonyl phospholipids (HOHA-PLs) that react with protein lysyl ε-amino residues to generate 2-ω-carboxyethylpyrrole (CEP) derivatives, endogenous factors that induce angiogenesis in the retina and tumors. It seemed likely, but remained unproven, that HOHA-PLs react with ethanolamine phospholipids (EPs) in vivo to generate CEP-EPs. We now show that CEP-EPs are present in human blood at 4.6-fold higher levels in age-related macular degeneration plasma than in normal plasma. We also show that CEP-EPs are pro-angiogenic, inducing tube formation by human umbilical vein endothelial cells by activating Toll-like receptor 2. CEP-EP levels may be a useful biomarker for clinical assessment of AMD risk and CEP-associated tumor progression and a tool for monitoring the efficacy of therapeutic interventions.

Redundant Signaling as the Predominant Mechanism for Resistance to Antibodies Targeting the Type-I Insulin-Like Growth Factor Receptor in Cells Derived from Childhood Sarcoma.

Antibodies targeting insulin-like growth factor 1 receptor (IGF-1R) induce objective responses in only 5% to 15% of children with sarcoma. Understanding the mechanisms of resistance may identify combination therapies that optimize efficacy of IGF-1R-targeted antibodies. Sensitivity to the IGF-1R-targeting antibody TZ-1 was determined in rhabdomyosarcoma and Ewing sarcoma cell lines. Acquired resistance to TZ-1 was developed and characterized in sensitive Rh41 cells. The BRD4 inhibitor, JQ1, was evaluated as an agent to prevent acquired TZ-1 resistance in Rh41 cells. The phosphorylation status of receptor tyrosine kinases (RTK) was assessed. Sensitivity to TZ-1 in vivo was determined in Rh41 parental and TZ-1-resistant xenografts. Of 20 sarcoma cell lines, only Rh41 was sensitive to TZ-1. Cells intrinsically resistant to TZ-1 expressed multiple (>10) activated RTKs or a relatively less complex set of activated RTKs (∼5). TZ-1 decreased the phosphorylation of IGF-1R but had little effect on other phosphorylated RTKs in all resistant lines. TZ-1 rapidly induced activation of RTKs in Rh41 that was partially abrogated by knockdown of SOX18 and JQ1. Rh41/TZ-1 cells selected for acquired resistance to TZ-1 constitutively expressed multiple activated RTKs. TZ-1 treatment caused complete regressions in Rh41 xenografts and was significantly less effective against the Rh41/TZ-1 xenograft. Intrinsic resistance is a consequence of redundant signaling in pediatric sarcoma cell lines. Acquired resistance in Rh41 cells is associated with rapid induction of multiple RTKs, indicating a dynamic response to IGF-1R blockade and rapid development of resistance. The TZ-1 antibody had greater antitumor activity against Rh41 xenografts compared with other IGF-1R-targeted antibodies tested against this model.

Polymorphic variations in IL-1ß, IL-6 and IL-10 genes, their circulating serum levels and breast cancer risk in Indian women.

BACKGROUND: Cytokines are known as important regulators of the entire gamut of cancer from initiation, invasion and metastasis. This fact and plethora of gene polymorphism data prompted us to investigate cytokine gene polymorphisms in breast cancer (BC) patients. METHODS: Selected polymorphisms in the IL-1ß [-511 T>C (rs16944) and +3954 C>T (rs1143634)]; IL-6 [-174 G>C (rs1800795)]; IL-10 [-1082 A>G (rs1800896), -819 T>C (rs1800871) and -592 A>C (rs1800872)] genes were genotyped in 200 BC patients and 200 healthy volunteers in a case-control study using PCR-RFLP and direct DNA sequencing techniques. Peripheral cytokine levels were measured using ELISA. Allele and genotype data were analyzed for significance of differences between cases and controls using Chi-Square [χ(2)] test. Two sided P-values of less than 0.05 were considered to be statistically significant. RESULTS: Peripheral level of all three cytokines did not show any significant difference between cases and controls. Allele and genotype frequency of IL-1ß [-511 T>C (rs16944)] did not show any difference between cases and controls. On the other hand mutant allele and genotype at IL-1ß [+3954 C>T (rs1143634)] associated with increased risk of BC. This was also true for pre-menopausal cases and for mutant genotype in post-menopausal cases. Mutant allele and genotypes at IL-6 [-174 G>C (rs1800795)] appeared to be protective in nature such that controls had a higher frequency of both mutant alleles and genotypes. None of the three SNPs in IL-10 gene associated with risk of BC, except significant association of mutant allele and genotypes of -1082 A>G (rs1800896) polymorphism with postmenopausal BC. CONCLUSIONS: Mutant allele and genotype at IL-1ß [+3954 C>T (rs1143634)] site associated with increased BC risk, while mutant allele and genotypes at IL-6 [-174 G>C (rs1800795)] polymorphism appeared to be protective. Also, there was significant association of mutant allele and genotypes of IL-10 [-1082 A>G (rs1800896)] with postmenopausal BC. None of the other polymorphisms investigated appear to affect BC risk.

An interleukin-10 gene promoter polymorphism (-592A/C) associated with type 2 diabetes: a North Indian study.

In this first report on the association of an IL-10 promoter polymorphism with type 2 diabetes mellitus in a North Indian population, the -592A/C SNP (rs1800872) was genotyped by PCR-RFLP and the IL-10 level measured using ELISA. Although no significant difference was observed in the genotypic frequencies (P = 0.657), diabetes patients carried a significantly higher number of A alleles at the -592 position, 25.6% (P < 0.001, odds ratio 0.887, 95% CI 0.670-1.184). Significant correlations were detected in postprandial glucose levels of CC-genotype patients and controls (P = 0.025), age and waist-hip ratio of CA patients and controls (P ≤ 0.001), and fasting glucose (P = 0.045) and low-density lipoprotein (P = 0.049) in all patients and controls. The serum IL-10 level was significantly higher in patients than in controls (P = 0.033). The polymorphism was significantly associated with disease incidence and its biochemical manifestations.

Vitamin D receptor as a therapeutic target for benign prostatic hyperplasia.

The bioactive form of vitamin D, 1α, 25-dihydroxyvitamin D3 (1α, 25(OH)2D3), is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the nuclear receptor super-family expressed in many cell types, and modulates a variety of biological functions. 1α, 25(OH)2D3 is essential for bone and mineral homeostasis, but also regulates growth and differentiation of multiple cell types, and displays immunoregulatory and anti-inflammatory activities. The antiproliferative, prodifferentiative, antibacterial, immunomodulatory and anti-inflammatory properties of synthetic VDR agonists could be exploited to treat a variety of chronic inflammatory and autoimmune diseases, including benign prostatic hyperplasia (BPH). It has been hypothesized that VDR may influence both the risk of a variety of diseases and their occurrence and prognosis. However, earlier studies investigating the associations between specific VDR polymorphisms and various diseases often show controversial results. We performed a systematic review of the current literature on vitamin D and BPH using the PubMed and Web of Knowledge databases. The aim of this review is to summarize the current knowledge on the utility of the VDR gene regarding prostate growth as well as the pathogenesis and treatment of BPH, a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary storage symptoms, and an inflammatory component. Despite the massive advances in recent decades, further research is needed to fully characterize the exact underlying mechanisms of VDR action on BPH and to comprehend how these cellular changes translate into clinical development in physical concert.

Splice-switching of the insulin receptor pre-mRNA alleviates tumorigenic hallmarks in rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is an aggressive pediatric tumor with a poor prognosis for metastasis and recurrent disease. Large-scale sequencing endeavors demonstrate that Rhabdomyosarcomas have a dearth of precisely targetable driver mutations. However, IGF-2 signaling is known to be grossly altered in RMS. The insulin receptor (IR) exists in two alternatively spliced isoforms, IR-A and IR-B. The IGF-2 signaling molecule binds both its innate IGF-1 receptor as well as the insulin receptor variant A (IR-A) with high affinity. Mitogenic and proliferative signaling via the canonical IGF-2 pathway is, therefore, augmented by IR-A. This study shows that RMS patients express increased IR-A levels compared to control tissues that predominantly express the IR-B isoform. We also found that Hif-1α is significantly increased in RMS tumors, portraying their hypoxic phenotype. Concordantly, the alternative splicing of IR adapts to produce more IR-A in response to hypoxic stress. Upon examining the pre-mRNA structure of the gene, we identified a potential hypoxia-responsive element, which is also the binding site for the RNA-binding protein CUG-BP1 (CELF1). We designed Splice Switching Oligonucleotides (SSO) against this binding site to decrease IR-A levels in RMS cell lines and, consequently, rescue the IR-B expression levels. SSO treatment resulted in a significant reduction in cell proliferation, migration, and angiogenesis. Our data shows promising insight into how impeding the IGF-2 pathway by reducing IR-A expression mitigates tumor growth. It is evident that Rhabdomyosarcomas use IR alternative splicing as yet another survival strategy that can be exploited as a therapeutic intervention in conjunction with already established anti-IGF-1 receptor therapies.

Role of ethnic variations in TNF-α and TNF-ß polymorphisms and risk of breast cancer in India.

TNF-α and -ß, the multi-functional pro-inflammatory cytokines, are known to play important roles in both tumor progression and destruction based on their concentrations. Growth factors and various stimuli such as cytokines regulate proliferation of the breast epithelial cells. Therefore, the polymorphisms in the genes encoding these signaling molecules could affect the risk of breast cancer. We have investigated selected genetic polymorphisms in TNF-α promoter (rs1800629, -308 G>A and rs361525, -238 G>A) and TNF-ß intron 1 (rs909253, +252 A>G) in ethnically two different case-control groups from India. The study included 200 cases and 200 controls from an Indo-European (North Indian) group, and 265 cases and 237 controls from a Dravidian (South Indian) group. Genotyping of a total of 902 individuals was done by direct DNA sequencing. None of the polymorphisms showed significant association with breast cancer in the Indo-European group; however, all the three polymorphisms showed strong association with breast cancer in the Dravidian group. Further, sub-group analysis in the Indo-European group showed no significant difference between pre-menopausal cases and controls or between post-menopausal cases and controls at any of the loci analyzed. However, all the polymorphisms in the Dravidian group were significantly associated with pre-menopausal but not with post-menopausal breast cancer. In conclusion, TNF-α and -ß polymorphisms are strongly associated with breast cancer in the Dravidian but not in the Indo-European group.

Design and synthesis of 1,3-biarylsulfanyl derivatives as new anti-breast cancer agents.

A new series of 1,3-biarylsulfanyl derivatives (homodibenzyl core motif) have been designed and synthesized as new estrogen receptor ligands by chopping benzothiophene core of raloxifene to engender seco-raloxifene scaffold. All the synthesized compounds were screened for anti-proliferative, anti-osteoporotic, and anti-implantation activity. Compounds (35, 36) having basic amino anti-estrogenic side chain were exhibiting potential anti-proliferative activity in MCF-7, MDA-MB-231 and ishikawa cell lines. Some of the synthesized compounds having homodibenzyl motif (5, 8, 10) have shown moderate anti-osteoporotic activity.

Preliminary studies on CD36 gene in type 2 diabetic patients from north India.

BACKGROUND & OBJECTIVES: The greater tendency to diabetes in Indians may be due to genetic factors in addition to environment and diet. CD36, a class B scavenger cell surface receptor mediates internalization of oxidized low density lipoprotein (Ox-LDL) leading to the formation of macrophage foam cells. CD36 deficiency is related to phenotypic expression of the metabolic syndrome, frequently associated with atherosclerotic cardiovascular diseases resulting in raised levels of glucose thereby contributing to type 2 diabetes (T2DM). Therefore, the association of human CD36 gene mutation to T2DM needs investigation. We undertook this study to investigate CD36 gene status in north Indian subjects by screening for the deletion of exons 3, 4 and 5 and certain polymorphisms. METHODS: Clinical characteristics were compared between 300 T2DM patients and 100 healthy controls. Deletion analysis was carried out for exons 3, 4 and 5 of CD36 gene in 300 T2DM patients using PCR and agarose gel electrophoresis. Genotype analysis for two polymorphisms 478C>T and delAC in exons 4 and 5 respectively was carried out using PCR-RFLP method. RESULTS: Biochemical parameters such as fasting and post-prandial glucose levels, total cholesterol, LDL-cholesterol and blood pressure were slightly raised in the T2DM patients when compared with controls with lowered HDL-cholesterol. No exonic deletion was observed in the 300 patients and 100 controls screened. All individuals were found to be homozygous (CC and -/-) for the two polymorphisms studied. INTERPRETATION & CONCLUSIONS: Although no exonic deletion was found in T2DM patients, our study suggests that all 15 exons need to be screened for mutations which lead to CD36 deficiency. Genotyping studies of the two SNPs in the CD36 gene confirmed the absence of exons 4 and 5 deletion. This is perhaps the first report from India suggesting that CD36 is one of the several important genes that need to be explored in relation to T2DM.

Targeting angiogenesis in childhood sarcomas.

Angiogenesis and vasculogenesis constitute two processes in the formation of new blood vessels and are essential for progression of solid tumors. Consequently, targeting angiogenesis, and to a lesser extent vasculogenesis, has become a major focus in cancer drug development. Angiogenesis inhibitors are now being tested in pediatric populations whereas inhibitors of vasculogenesis are in an earlier stage of development. Despite the initial enthusiasm for targeting angiogenesis for treatment of cancer, clinical trials have shown only incremental increases in survival, and agents have been largely cytostatic rather than inducing tumor regressions. Consequently, the role of such therapeutic approaches in the context of curative intent for childhood sarcomas is less clear. Here we review the literature on blood vessel formation in sarcomas with a focus on pediatric sarcomas and developments in targeting angiogenesis for treatment of these rare cancers.

Functional characterization of miR-708 microRNA in telomerase positive and negative human cancer cells.

Activation of a telomere length maintenance mechanism (TMM), including telomerase and alternative lengthening of telomeres (ALT), is essential for replicative immortality of tumor cells, although its regulatory mechanisms are incompletely understood. We conducted a microRNA (miRNA) microarray analysis on isogenic telomerase positive (TEP) and ALT cancer cell lines. Amongst nine miRNAs that showed difference in their expression in TEP and ALT cancer cells in array analysis, miR-708 was selected for further analysis since it was consistently highly expressed in a large panel of ALT cells. miR-708 in TEP and ALT cancer cells was not correlated with C-circle levels, an established feature of ALT cells. Its overexpression induced suppression of cell migration, invasion, and angiogenesis in both TEP and ALT cells, although cell proliferation was inhibited only in TEP cells suggesting that ALT cells may have acquired the ability to escape inhibition of cell proliferation by sustained miR-708 overexpression. Further, cell proliferation regulation in TEP cells by miR708 appears to be through the CARF-p53 pathway. We demonstrate here that miR-708 (i) is the first miRNA shown to be differentially regulated in TEP and ALT cancer cells, (ii) possesses tumor suppressor function, and (iii) deregulates CARF and p21WAF1-mediated signaling to limit proliferation in TEP cells.

Neo-tanshinlactone inspired synthesis, in vitro evaluation of novel substituted benzocoumarin derivatives as potent anti-breast cancer agents.

A small library of novel benzocoumarin derivatives based on naturally occurring neo-tanshinlactone scaffold was constructed and their antiproliferative activities against breast cancer cells MCF-7 and MDA-MB-231 were evaluated. A number of derivatives showed good anti-breast cancer activity, in some cases higher to that of the reference compound tamoxifen. In particular, benzocoumarins Bc-5, Bc-8 and Bc-9 strongly inhibited the proliferation of MCF-7 cancer cell line with the IC(50) values of 3.8, 7.9 and 6.5 µM, respectively. The compounds were capable of inducing nuclear fragmentation, cell cycle arrest and caspase dependent apoptosis in MCF-7 cell lines. In addition, these derivatives were devoid of cytotoxic effect against normal osteoblast cells. These synthetic benzocoumarins hold promises for developing safer alternative to the existing anti-breast cancer agents.

Anti-tumor activity of a new series of benzoxazepine derivatives in breast cancer.

A series of new benzoxazepine derivatives substituted with different alkoxy and aryloxy group were synthesized comprising synthetic steps of Mitsunobu reaction, lithium aluminum hydride (LAH) reduction, followed by debenzylation and finally intramolecular Mitsunobu cyclization. The new benzoxazepines specifically inhibited growth of breast cancer cell lines, MCF-7 and MDA-MB-231, but lack cytotoxicity to normal HEK-293 cells. The cell growth inhibition induced by the active compounds was due to cell cycle arrest at G(0)/G(1) phase. The active compound could cause significant reduction in tumor volume of MCF-7 xenograft tumor in nude mice model and their activity was comparable to that of tamoxifen citrate at 16mgkg(-1) dose at 30days of treatment. The identified most active compounds of the series have specific advantages as anti-cancer agent in breast cancer than tamoxifen.