Glucagon-like peptide-1 analogs activate AMP kinase leading to reversal of the Warburg metabolic switch in breast cancer cells.

Breast cancer (BC) is associated with type 2 diabetes mellitus (T2DM) and obesity. Glucagon-like peptide (GLP)-1 regulates post-prandial insulin secretion, satiety, and gastric emptying. Several GLP-1 analogs have been FDA-approved for the treatment of T2DM and obesity. Moreover, GLP-1 regulates various metabolic activities across different tissues by activating metabolic signaling pathways like adenosine monophosphate (AMP) activated protein kinase (AMPK), and AKT. Rewiring metabolic pathways is a recognized hallmark of cancer, regulated by several cancer-related pathways, including AKT and AMPK. As GLP-1 regulates AKT and AMPK, we hypothesized that it alters BC cells' metabolism, thus inhibiting proliferation. The effect of the GLP-1 analogs exendin-4 (Ex4) and liraglutide on viability, AMPK signaling and metabolism of BC cell lines were assessed. Viability of BC cells was evaluated using colony formation and MTT/XTT assays. Activation of AMPK and related signaling effects were evaluated using western blot. Metabolism effects were measured for glucose, lactate and ATP. Exendin-4 and liraglutide activated AMPK in a cAMP-dependent manner. Blocking Ex4-induced activation of AMPK by inhibition of AMPK restored cell viability. Interestingly, Ex4 and liraglutide reduced the levels of glycolytic metabolites and decreased ATP production, suggesting that GLP-1 analogs impair glycolysis. Notably, inhibiting AMPK reversed the decline in ATP levels, highlighting the role of AMPK in this process. These results establish a novel signaling pathway for GLP-1 in BC cells through cAMP and AMPK modulation affecting proliferation and metabolism. This study suggests that GLP-1 analogs should be considered for diabetic patients with BC.

Sterile Water Versus Glycine in Transurethral Resection of Bladder Tumors-Immunogenic and Clinical Implications.

BACKGROUND AND OBJECTIVE: We compared the oncologic outcomes of patients with non-muscle invasive bladder cancer (NMIBC) who underwent transurethral resection of bladder tumor (TUBRT) using sterile water vs glycine irrigation. The tumoricidal and immunogenic effects of these solutions on urothelial cancer cell lines were investigated. METHODS: The medical records of 530 consecutive patients who underwent TURBT using sterile water or glycine irrigation for NMIBC were reviewed. Recurrence and progression rates were evaluated using time dependent analyses.Bladder cancer cell lines (RT4, T24 and 5637) were treated with glycine and sterile water. Cell viability was evaluated with the XTT assay. Cell membrane calreticulin levels were evaluated with flow cytometry. Extracellular high mobility group box 1 (HMGB1) and heat shock 70 (HSP70) protein levels were evaluated using western blots. KEY FINDINGS AND LIMITATIONS: After propensity score matching each study arm comprised 161 patients. Median follow-up was 13.6 months (IQR 6.2, 24.5). The 2-year recurrence free survival was significantly lower in the sterile water vs glycine group (43% vs 71%, respectively, p<0.0001). Similarly, the 2-years progression free survival was significantly lower in the sterile water vs glycine group (85% vs 94%, respectively, p<0.014). Sterile water treatment resulted in the lowest number of viable cells. Early and late immunogenic cell death markers were markedly elevated in cells treated with glycine. CONCLUSIONS AND CLINICAL IMPLICATIONS: Sterile water compared to glycine irrigation during TURBT for NMIBC was associated with higher recurrence and progression rates. Possible explanation for these findings is the diminished immune response associated with sterile water reflected in a comparatively lesser expression of immune response inducers. PATIENT SUMMARY: We compared two irrigation fluids in non-muscle-invasive bladder cancer surgery: glycine and sterile water. Glycine outperformed sterile water in cancer recurrence, possibly boosting immunogenicity over sterile water.

Physiotherapists' perceptions of implementing evidence-based practice for patients with low back pain through the Enhanced Transtheoretical Model Intervention: a qualitative study.

BACKGROUND: Physiotherapists have been urged to implement evidence-based practice for the management of low back pain (LBP). However, recent evidence suggests that many fail to do so, specifically in accordance with eliciting and addressing psychosocial factors that impact pain. The Enhanced Transtheoretical Model Intervention (ETMI) for the Treatment of patients with LBP was developed in Israel according to the clinical guidelines and demonstrated clinically and cost-effectiveness. OBJECTIVES: This study's purpose is to explore physiotherapists' perceptions of implementing evidence-based practice through the ETMI approach. DESIGN: Qualitative study. METHODS: Qualitative semi-structured interviews were conducted with 26 physiotherapists. The interviews were audio-recorded, transcribed, coded, and analyzed thematically to identify prevalent themes. RESULTS: Three main themes were identified from the transcripts, consisting of barriers and facilitators of implementing the intervention, and a meta-theme referring to shifts in the perceptions of professional role and identity. CONCLUSION: The findings suggest that physiotherapists believed that implementing ETMI and adopting a psychosocial approach to LBP can be achieved by overcoming issues around communication skills, patient reassurance, and inter-professional collaboration. Therapists also highlighted the need for physiotherapy training to gain skills in combined physical and psychological approaches.

Patients' Perceptions and Outcome Measures after Undergoing the Enhanced Transtheoretical Model Intervention (ETMI) for Chronic Low Back Pain: A Mixed-Method Study.

This study aimed to evaluate the outcome measures and perceptions of patients with chronic low back pain (CLBP) after being treated with the Enhanced Transtheoretical Model Intervention (ETMI). In this process evaluation mixed-methods study, 30 patients with CLBP electronically completed self-reported measures (function, pain, and fear-avoidance beliefs) before and after ETMI treatment. Subsequently, each patient participated in one-on-one, semi-structured interviews, which were audio-recorded, transcribed, coded, and analyzed thematically. Quantitative analysis showed significant improvements in function (p < 0.001), pain (p < 0.001), and fear-avoidance beliefs (p < 0.001) after receiving ETMI treatment, with a large effect size (Cohen's d = 1.234). Moreover, the average number of physiotherapy sessions was 2.6 ± 0.6 for the ETMI intervention, while the annual average number in Maccabi is estimated at 4.1 ± 1.5. Three main themes emerged from the thematic analysis: (1) communication between the patient and the practitioner; (2) psychosocial treatment elements, and (3) ETMI as a long-term solution for CLBP. The findings of the current study highlight patients' perceived need for an open and sincere dialogue and for receiving reassurance and encouragement about their LBP. Notably, they had no problem with the fact that they did not receive passive treatment. Accordingly, together with the significant improvement in post-treatment outcome measures, patients perceived the ETMI method as a practical tool for self-managing their back problems in the long term.

Patients' prior perceptions and expectations of the Enhanced Transtheoretical Model Intervention for chronic low back pain: A qualitative study.

BACKGROUND: The Enhanced Transtheoretical Model Intervention (ETMI) is an approach for treating chronic low back pain (CLBP), which demonstrated clinical and cost-effectiveness outcomes. ETMI highlights reassurance, return to normal activities and encouragement of recreational physical activity. In order to optimally implement ETMI, it is important to gain an understanding of the expectations and perceptions of patients before they engage with the intervention. OBJECTIVES: To explore CLBP patients' perceptions and expectations of the ETMI method prior to their first consultation with physiotherapist. METHODS: Qualitative semi-structured interviews were conducted with 30 CLBP patients. The interviews were audio-recorded, transcribed, coded, and analysed thematically. Patients were first asked about their expectations of treatment, then they were asked to comment on the ETMI method. RESULTS: Three main themes emerged from the interviews: (1) Patient's perceptions of LBP; (2) patient's expectations from current physiotherapy and (3) Patient's expectations from ETMI method. The patients' perceptions of back pain centred on biomechanical causal factors, a desire for diagnostic tests and beliefs that rest cures the pain. Their expectations from current physiotherapy included pain reduction, passive treatment, a structured exercise program and clear information about LBP. In reference to the ETMI method, patients expected pain reduction, practical tools to self-manage, and a combination of ETMI with passive treatment. CONCLUSION: addressing issues around patient's perceptions and expectations of current physiotherapy and of the ETMI method, prior to their first consultation with physiotherapist, could be beneficial for understanding how to improve the ETMI implementation in the health care system.

Comprehensive Molecular and Clinicopathologic Analysis of 200 Pulmonary Invasive Mucinous Adenocarcinomas Identifies Distinct Characteristics of Molecular Subtypes.

PURPOSE: Invasive mucinous adenocarcinoma (IMA) is a unique subtype of lung adenocarcinoma, characterized genomically by frequent KRAS mutations or specific gene fusions, most commonly involving NRG1. Comprehensive analysis of a large series of IMAs using broad DNA- and RNA-sequencing methods is still lacking, and it remains unclear whether molecular subtypes of IMA differ clinicopathologically. EXPERIMENTAL DESIGN: A total of 200 IMAs were analyzed by 410-gene DNA next-generation sequencing (MSK-IMPACT; n = 136) or hotspot 8-oncogene genotyping (n = 64). Driver-negative cases were further analyzed by 62-gene RNA sequencing (MSK-Fusion) and those lacking fusions were further tested by whole-exome sequencing and whole-transcriptome sequencing (WTS). RESULTS: Combined MSK-IMPACT and MSK-Fusion testing identified mutually exclusive driver alterations in 96% of IMAs, including KRAS mutations (76%), NRG1 fusions (7%), ERBB2 alterations (6%), and other less common events. In addition, WTS identified a novel NRG2 fusion (F11R-NRG2). Overall, targetable gene fusions were identified in 51% of KRAS wild-type IMAs, leading to durable responses to targeted therapy in some patients. Compared with KRAS-mutant IMAs, NRG1-rearranged tumors exhibited several more aggressive characteristics, including worse recurrence-free survival (P < 0.0001). CONCLUSIONS: This is the largest molecular study of IMAs to date, where we demonstrate the presence of a major oncogenic driver in nearly all cases. This study is the first to document more aggressive characteristics of NRG1-rearranged IMAs, ERBB2 as the third most common alteration, and a novel NRG2 fusion in these tumors. Comprehensive molecular testing of KRAS wild-type IMAs that includes fusion testing is essential, given the high prevalence of alterations with established and investigational targeted therapies in this subset.

Delivery of Radiation at the Lowest Dose Rate by a Modern Linear Accelerator is Most Effective in Inhibiting Prostate Cancer Growth.

PURPOSE: External beam radiotherapy is one of the treatment options for organ-confined prostate cancer. A total dose of 70 to 81 Gray (Gy) is given daily (1.8-2.5 Gy/d), with a dose rate of 3 to 6 Gy/min over 28 to 45 treatments during 8 to 9 weeks. We applied the latest technological development in linear accelerators for enabling a wide range of dose rates (from 0.2-21 Gy/min) to test the effect of different delivery dose rates on prostate tumor growth in an animal xenograft model. MATERIALS AND METHODS: A prostate cancer xenograft model was established in CD1/nude mice by means of PC-3 and CL-1 cells. The animals were radiated by a TrueBeam linear accelerator that delivered 4 dose rates ranging from 0.6 to 14 Gy/min, and reaching a total dose of 20 Gy. The mice were weighed and monitored for tumor development twice weekly. A 2-way analysis of variance was used to compare statistical differences between the groups. RESULTS: Tumor growth was inhibited by radiation at all 4 dose rates in the 20 study mice compared to no radiation (n = 5, controls). The most significant reduction in tumor volumes was observed when the same dose of radiation was delivered at a rate of 0.6 Gy/min (P < .01). The animals' weights were not affected by any dose rate. CONCLUSIONS: Delivery of radiation with a TrueBeam linear accelerator at the lowest possible rate was most effective in prostate cancer growth inhibition and might be considered a preferential treatment mode for localized prostate cancer.

ß-TrCP upregulates HIF-1 in prostate cancer cells.

The substantial availability of hypoxia-inducible factor 1 (HIF-1) for pathophysiological states, such as malignancies and ischemia, is primarily regulated post-translationally through the ubiquitin proteolytic system. The balance between degradation and stabilization of HIF-1α protein is determined by specific E3 ligases. In our search for new E3 ligases that might affect HIF-1α protein expression, we studied the effects of beta-transducin repeat-containing protein (ß-TrCP) on the hypoxic pathway in cancer cells. ß-TrCP is overexpressed in many tumors and regulates various cellular processes through mediating the degradation of important targets. Unexpectedly, we found that ß-TrCP overexpression increases HIF-1α protein expression level as well as HIF-1 transcriptional activity by stabilizing HIF-1α protein and preventing its ubiquitination and proteasomal degradation in prostate cancer cells. By using a proteomic approach, we succeeded in demonstrating that ß-TrCP interferes with the association between HIF-1α and HSP70/CHIP, a HIF-1α established E3 ligase complex. Whereas the E3 ligase activity of ß-TrCP is well known, antagonizing another E3 ligase is a new mechanism of action of this important E3. We suggest that destroying or suppressing ß-TrCP and thereby interrupting the HIF-1 pathway, could be valuable antitumor therapy.

microRNA expression profiles as decision-making biomarkers in the management of bladder cancer.

Bladder cancer (BC) is generally divided into non-muscle-invasive BC (NMIBC) and muscle-invasive BC (MIBC). The standard treatment protocol for MIBC patients is radical cystectomy preceded by neoadjuvant chemotherapy (NAC). About one-half of the MIBC patients show a priori resistance to chemotherapy, and are therefore exposed to the risks of disease progression and toxicity from ineffective NAC. The discovery of microRNA (miRNA) regulation in tumorigenesis has provided new directions for the development of a new type of BC biomarkers. In this review, we describe the emerging miRNAs as BC biomarkers for different purposes, including diagnosis, prognosis and therapeutic response. miRNA expression profile changes with alteration of the tissue phenotype. This phenomenon is utilized to predict tumor diagnosis, cancer subclass, disease stage, prognosis and therapeutic response. We classified the miRNAs which are involved in bladder cancer according to malignant potential, chemoresistance, discrimination between normal to cancerous and clinical outcome. Focusing on the major obstacle regarding MIBC patient's NAC response, we summarized the miRNAs that are deregulated and have the potential to identify the patients resistant to NAC, such as miR-34, miR-100, miR-146b and miR-9 and miR-193a-3p. In conclusion, miRNAs expression profile of bladder cancer patient is a promising tool that can serve as biomarker for different aims. Based on this profile we propose upfront radical cystectomy instead of standard NAC to those MIBC patients who are at higher risk for chemoresistance and poor response.

Galectin-3 is a sensor-regulator of toll-like receptor pathways in synovial fibroblasts.

Galectin-3 is a ß-galactoside-binding lectin that plays an important role in the modulation of immune responses. It has been shown to aggravate joint inflammation and destruction in experimental arthritis. We investigated the role of galectin-3 in TLR-induced cell activation in human synovial fibroblasts (SF) in order to better understand the mechanism(s) of the proinflammatory function of galectin-3 in arthritis. Galectin-3 expression in SF obtained from rheumatoid arthritis and osteoarthritis patients was inhibited by siRNA mediated gene-knockdown. Galectin-3 was also inhibited with modified citrus pectin (MCP), a polysaccharide galectin-3 ligand. Galectin-3 knockdown inhibited TLR-2, -3 and -4-induced IL-6 secretion, but not TLR-2, -3 and -4-mediated matrix metalloproteinase-3 or CC chemokine ligand-5 secretion. When the SF were stimulated with phorbol 12-myristate 13-acetate, a protein kinase C activator that bypasses the membranal receptors, galectin-3 knockdown no longer influenced IL-6 secretion. MCP reduced IL-6 levels in a dose-dependent manner. Our results indicate that galectin-3 is a positive sensor-regulator of TLR-induced IL-6 secretion in human synovial fibroblasts, thus adding new insights into the mechanisms by which galectin-3 augments synovial inflammation. These findings corroborate the potential role of glycan inhibitors of galectin-3 as a therapeutic approach for the treatment of inflammatory arthritis.

HIF1A C1772T polymorphism leads to HIF-1α mRNA overexpression in prostate cancer patients.

Hypoxia-inducible factor 1α (HIF-1α) gene polymorphisms have been investigated for a possible role in mediating genetic predisposition to cancer. Our previous data show that men homozygous to C1772T polymorphism had 4-fold risk to develop prostate cancer. Therefore, we studied the effects of C1772T polymorphism on HIF-1α expression. HIF-1α mRNA expression levels were significantly higher in peripheral blood leukocytes of prostate cancer patients with the TT genotype compared with the CC genotype. Expression of C1772T HIF-1α in HIF-1α knockout cancer cells showed higher expression levels and stabilization of HIF-1α mRNA compared with the wild-type. Mutated HIF-1α protein half-life was similar to that of the wild-type. Hence, our data provide evidence that C1772T polymorphism causes activation of HIF-1α as a gain-of-function mechanism driven by stabilization of HIF-1α mRNA. These findings may also explain the increased risk of men homozygous to this mutation to develop prostate cancer.

Efficacy and safety of vaccination against pandemic 2009 influenza A (H1N1) virus among patients with rheumatic diseases.

OBJECTIVE: To assess the efficacy and safety of vaccination against pandemic H1N1 virus in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) compared with healthy controls. METHODS: The study population comprised 41 RA patients, 21 SLE patients, 17 PsA patients, 15 AS patients, and 25 healthy controls. All were vaccinated using the Novartis MF59-adjuvanted H1N1v monovalent influenza vaccine. The immunogenicity of the vaccine was assessed on day 1 and again 4 weeks later by hemagglutination inhibition assay. Geometric mean titers and seroconversion rates were calculated for each group. The safety of the vaccine was evaluated using the 28-joint Disease Activity Score (DAS28) for RA and PsA, the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). RESULTS: The proportion of baseline protective levels of antibodies against H1N1 was similar in all but the AS group, in which it was lower. The geometric mean titers increased significantly in all 5 groups. A substantial proportion of patients and controls responded to the vaccine. The healthy controls demonstrated a better response than each of the other groups: 84% versus 56% for RA, 67% for SLE, 59% for PsA, and 53% for AS. Multivariate logistic regression analysis identified RA and PsA as parameters of significantly lower response. The DAS28, BASDAI, and SLEDAI remained unchanged after vaccination. CONCLUSION: Vaccination against pandemic H1N1 using an adjuvanted H1N1v monovalent influenza is safe and induced an appropriate response in patients with RA, SLE, PsA, and AS.

Hypoxia induces PTHrP gene transcription in human cancer cells through the HIF-2α.

Parathyroid hormone-related protein (PTHrP) expressed by human cancer cells enhances tumor cell growth and metastasis in vivo and it is considered as the major factor responsible for humoral hypercalcemia of malignancy. Hypoxia is a widespread feature of most solid tumors. Here, we studied the effects of hypoxia on PTHrP expression. We found that PTHrP is transcriptionally induced by prolonged (48 h) hypoxia in multiple human cancer and endothelial cell lines. Pharmacological up or downregulation of hypoxia-inducible factor (HIF) resulted in induction or reduction of PTHrP levels, respectively, implying that PTHrP hypoxic induction is mediated by HIF pathway. Analysis of PTHrP promoter revealed that both HIF-1α and HIF-2α subunits bind to specific hypoxia-responsive elements (HRE) within the P2 promoter of PTHrP. However, only HIF-2α can drive direct transcriptional activation, which can be abolished by mutation in the specific HRE. To the best of our knowledge, these results provide for the first time evidence that PTHrP is regulated by hypoxia in cancer and endothelial cells through the HIF-2 pathway. We suggest that HIF-2 induced by intratumoral hypoxia or by other genetic alterations may contribute to the pathogenesis of hypercalcemia of malignancy and cancer aggressiveness by stimulation of PTHrP expression.

Targeted knockdown of SEPT9_v1 inhibits tumor growth and angiogenesis of human prostate cancer cells concomitant with disruption of hypoxia-inducible factor-1 pathway.

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor in the hypoxic response pathway. We recently identified a novel interaction between HIF-1alpha and the mammalian septin family member, septin 9 protein, isoform 1 (SEPT9_i1), a protein product of septin 9 transcript variant 1 (SEPT9_v1). Septins are a highly conserved family of GTP-binding cytoskeletal proteins that are implicated in multiple cellular functions, including oncogenesis. SEPT9_i1 binds and stabilizes HIF-1alpha protein and stimulates HIF-1 transcriptional activity by preventing its RACK1-mediated ubiquitination and degradation. SEPT9_i1-HIF-1 activation promotes tumor growth and angiogenesis. The effect of SEPT9_v1 silencing in prostate cancer cells was studied. SEPT9_v1 stable knockdown was generated in PC-3 cells using a specific shRNA. SEPT9_v1 silencing reduced HIF-1alpha protein expression and inhibited HIF-1 transcriptional activity. SEPT9_v1 knockdown affected cell morphology, deregulated cell cycle, and decreased migration. The antiproliferative effect of shSEPT9_v1 was abolished in HIF-1alpha knockout colon cancer cells. In vivo, SEPT9_i1 depletion reduced HIF-1alpha protein expression, cellular proliferation, tumor growth, and angiogenesis. These results provide new insights and validation for applying SEPT9_v1 as a potential target for antitumor therapy by interrupting the HIF-1 pathway.

Detection of prostate specific transcripts in the peripheral blood during brachytherapy predicts postoperative PSA kinetics.

BACKGROUND: We evaluated whether detection of prostate-specific antigen (PSA) and human kallikrein 2 (hK2) transcripts in the peripheral blood during brachytherapy could predict biochemical outcome. METHODS: Eighty-one patients who underwent (125)Iodine-based brachytherapy for localized prostate cancer (Gleason score <8, PSA <20 ng/ml, stage

SEPT9_v1 up-regulates hypoxia-inducible factor 1 by preventing its RACK1-mediated degradation.

A critical mediator of the cellular response to hypoxia is hypoxia-inducible factor 1 (HIF-1). Increased levels of HIF-1alpha are often associated with increased tumor metastasis, therapeutic resistance, and poorer prognosis. We recently identified a novel interaction between HIF-1alpha and the mammalian septin family member, SEPT9_v1. Septins are a highly conserved family of GTP-binding cytoskeletal proteins that are implicated in multiple cellular functions, including cell division and oncogenesis. SEPT9_v1 binds and stabilizes HIF-1alpha protein and stimulates HIF-1 transcriptional activity. SEPT9_v1-HIF-1 activation promotes tumor growth and angiogenesis. The structural and functional relationships between SEPT9_v1 and HIF-1alpha were analyzed. We found that SEPT9_v1 binds specifically with HIF-1alpha but not with HIF-2alpha. The GTPase domain of SEPT9_v1 was identified as essential for HIF-1alpha binding. A GTPase domain-derived polypeptide, corresponding to amino acids 252-379, was able to disrupt HIF-1alpha-SEPT9_v1 interaction and to inhibit HIF-1 transcriptional activity. SEPT9_v1 also protected HIF-1alpha from degradation induced by HSP90 inhibition by preventing the interaction of HIF-1alpha with the RACK1 protein, which promotes its oxygen-independent proteasomal degradation. In conclusion, a new mechanism of oxygen-independent activation of HIF-1 has been identified that is mediated by SEPT9_v1 blockade of RACK1 activity on HIF-1alpha degradation.

Potentiation of 2-methoxyestradiol-induced cytotoxicity by blocking endothelin A receptor in prostate cancer cells.

BACKGROUND: 2-Methoxyestradiol (2ME2) is an antitumoral and antiangiogenic compound that inhibits hypoxia-inducible factor (HIF)-1, a key regulator of the hypoxic response that promotes tumor progression. HIF-1alpha, the regulated subunit of HIF-1, is overexpressed in premalignant, cancerous and metastatic lesions of prostate. Endothelin (ET)-1 is a HIF target gene and one that plays an important role during prostate bone metastasis via its interaction with endothelin A (ET(A)) receptor. We reasoned that 2ME2 combined with an ET(A) receptor antagonist would induce potent cytotoxic effects in prostate cancer cells. METHODS: PC-3 and LNCaP cells were grown alone or cocultured with human osteoblasts. The cells were treated with 2ME2, with an ET(A) receptor antagonist (BQ-123) or with combinations of both compounds. The cells were then evaluated for cytotoxicity, HIF-1alpha protein expression and HIF-1 transcriptional activity. RESULTS: The combination of 2ME2 with BQ-123 induced synergistic cytotoxic effects in prostate cancer cells and in their cocultures with osteoblasts. No synergism was observed when 2ME2 was combined with the ET(B) selective antagonist, BQ-788. These results correlated with inhibition of HIF-1alpha protein expression, HIF-1 transcriptional activity, and PSA mRNA expression. CONCLUSIONS: The ET(A) receptor antagonist was capable of potentiating the cytotoxic effects of 2ME2 in prostate cancer cells. These effects were apparently mediated through the inhibition of the HIF-1 pathway. Our in vitro data strengthen the rationale for using 2ME2 in combination with ET(A) receptor antagonists for the treatment of metastatic prostate cancer.

SEPT9_V1 protein expression is associated with human cancer cell resistance to microtubule-disrupting agents.

SEPT9 is a mammalian septin family member. There is growing evidence that SEPT9 plays a role in cancer. The protein product, SEPT9_V1, associates with microtubules and interacts with hypoxia-inducible factor (HIF)-1alpha, the regulated subunit of the key transcription factor HIF-1. HIF-1 transcriptional activity is thoroughly dependent on intact microtubules. We tested the hypothesis that SEPT9_V1 confers resistance to microtubule-mediated HIF-1 inhibitors. SEPT9_V1 protein expression was strongly correlated with susceptibility of a wide range of cancer cells to 2-methoxyestradiol and paclitaxel. Our results revealed that SEPT9_V1 could serve as a biomarker for therapeutic resistance to microtubule disrupting agents.

1alpha,25-dihydroxyvitamin D3 (Calcitriol) inhibits hypoxia-inducible factor-1/vascular endothelial growth factor pathway in human cancer cells.

In vitro and in vivo studies have shown that 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] inhibits angiogenesis in cancer. We now examined whether the antiangiogenic effects of 1,25(OH)(2)D(3) are mediated by the hypoxia-inducible factor (HIF)-1 pathway. Our results showed that 1,25(OH)(2)D(3) reduces the protein expression of both the regulated HIF-1alpha subunit and the vascular endothelial growth factor (VEGF) in various human cancer cells. 1,25(OH)(2)D(3) also inhibited HIF-1 transcriptional activity (measured by reporter gene assay) as well as HIF-1 target genes, including VEGF, ET-1, and Glut-1. We also showed that 1,25(OH)(2)D(3) inhibits cell proliferation under hypoxia. Using HIF-1alpha knockout colon cancer cells, we show that the inhibition of the hypoxia-induced VEGF by 1,25(OH)(2)D(3) is mediated through a HIF-dependent pathway. Because HIF-1 is a major positive contributor in human tumorigenesis and angiogenesis, we believe that its inhibition by 1,25(OH)(2)D(3) strengthens the rationale to use vitamin D and its low-calcemic analogues in cancer chemoprevention and therapy.

MSF-A interacts with hypoxia-inducible factor-1alpha and augments hypoxia-inducible factor transcriptional activation to affect tumorigenicity and angiogenesis.

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor in the signaling pathway that controls the hypoxic responses of cancer cells. Activation of the HIF system has been observed in carcinogenesis and numerous cancers. We found an interaction between a member of the mammalian septin gene family (MSF-A) and the HIF system. MSF-A is a nuclear protein that interacts with HIF-1alpha protein to prevent its ubiquitination and degradation, thus activating the HIF transcriptome. Cells overexpressing MSF-A protein exhibit increased HIF transcriptional activity and higher proliferation rates in vitro and in vivo. Xenograft-derived human tumors from these cells were larger and more vascular. These findings link a function of a septin protein with angiogenesis through activation of the HIF pathway.