Hollow microneedle assisted intradermal delivery of hypericin lipid nanocapsules with light enabled photodynamic therapy against skin cancer.

Photodynamic therapy (PDT) to manage non-melanoma skin cancers has garnered great attention over the past few years. Hypericin (Hy) is a potent lipid-soluble photosensitiser with promising anticancer therapeutic activities. Nevertheless, its poor water-solubility, aggregation in biological systems and insufficient skin penetration restricted its effective exploitation. Herein, we report for the first-time encapsulation of Hy into lipid nanocapsules (Hy-LNCs), and then application of an AdminPen™ hollow microneedles (Ho-MNs) array and an in-house fabricated Ho-MN to enable efficient intradermal delivery. The physicochemical properties, photoactivity, ex vivo drug distribution and cellular uptake were evaluated. Results showed that Hy-LNCs were successfully formed with a particle size of 47.76 ± 0.49 nm, PDI of 0.12 ± 0.02, high encapsulation efficiency (99.67% ± 0.35), 396 fold higher photoactivity, 7 fold higher skin drug deposition, significantly greater cellular uptake and higher photocytotoxicity compared to free Hy. The therapeutic effect of Hy-LNCs was finally assessed in vivo using a nude mouse model with transplanted tumours. Interestingly, Hy-LNCs delivered by Ho-MN exhibited remarkable anti-tumour destruction (85.84%) after irradiation with 595 nm. This study showed that Ho-MNs-driven delivery of Hy-LNCs followed by irradiation could form a promising minimally invasive, effective and site-specific approach for managing non-melanoma skin cancers.

Autophagic secretion of HMGB1 from cancer-associated fibroblasts promotes metastatic potential of non-small cell lung cancer cells via NFκB signaling.

Tumor progression requires the communication between tumor cells and tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are major components of stromal cells. CAFs contribute to metastasis process through direct or indirect interaction with tumor cells; however, the underlying mechanism is largely unknown. Here, we reported that autophagy was upregulated in lung cancer-associated CAFs compared to normal fibroblasts (NFs), and autophagy was responsible for the promoting effect of CAFs on non-small cell lung cancer (NSCLC) cell migration and invasion. Inhibition of CAFs autophagy attenuated their regulation on epithelial-mesenchymal transition (EMT) and metastasis-related genes of NSCLC cells. High mobility group box 1 (HMGB1) secreted by CAFs mediated CAFs' effect on lung cancer cell invasion, demonstrated by using recombinant HMGB1, HMGB1 neutralizing antibody, and HMGB1 inhibitor glycyrrhizin (GA). Importantly, the autophagy blockade of CAFs revealed that HMGB1 release was dependent on autophagy. We also found HMGB1 was responsible, at least in part, for autophagy activation of CAFs, suggesting CAFs remain active through an autocrine HMGB1 loop. Further study demonstrated that HMGB1 facilitated lung cancer cell invasion by activating the NFκB pathway. In a mouse xenograft model, the autophagy specific inhibitor chloroquine abolished the stimulating effect of CAFs on tumor growth. These results elucidated an oncogenic function for secretory autophagy in lung cancer-associated CAFs that promotes metastasis potential, and suggested HMGB1 as a novel therapeutic target.

Hypoxia-targeted cupric-tirapazamine liposomes potentiate radiotherapy in prostate cancer spheroids.

In this study, novel cupric-tirapazamine [Cu(TPZ)2]-liposomes were developed as an effective hypoxia-targeted therapeutic, which potentiated radiotherapy in a three dimensional (3D) prostate cancer (PCa) model. To overcome the low water solubility of the Cu(TPZ)2, a remote loading method was developed to efficiently load the lipophilic complex into different liposomal formulations. The effect of pH, temperature, PEGylation, lipid composition, liposome size, lipid: complex ratio on the liposome properties, and drug loading was evaluated. The highest loading efficiency was obtained at neutral pH, which was independent of lipid composition and incubation time. In addition, enhanced drug loading was achieved upon decreasing the lipid:complex molar ratio with minimal effects on liposomes' morphology. Interestingly, the in vitro potency of the developed liposomes was easily manipulated by changing the lipid composition. The hydrophilic nature of our liposomal formulations improved the complex's solubility, leading to enhanced cellular uptake and toxicity, both in PCa monolayers and tumour spheroids. Moreover, Cu(TPZ)2-loaded liposomes combined with radiation, showed a significant reduction in PCa spheroids growth rate, compared to the free complex or radiation alone, which could potentiate radiotherapy in patients with localised advanced PCa.

HDAC6 Degradation Inhibits the Growth of High-Grade Serous Ovarian Cancer Cells.

Histone deacetylase 6 (HDAC6) is a unique histone deacetylating enzyme that resides in the cell cytoplasm and is linked to the modulation of several key cancer related responses, including cell proliferation and migration. The promising anti-cancer response of the first-generation HDAC6 catalytic inhibitors continues to be assessed in clinical trials, although its role in high grade serous ovarian cancer is unclear. This study investigated HDAC6 tumor expression by immunohistochemistry in high-grade serous ovarian cancer (HGSOC) tissue samples and a meta-analysis of HDAC6 gene expression in ovarian cancer from publicly available data. The pharmacological activity of HDAC6 inhibition was assessed in a patient-derived model of HGSOC. HDAC6 was found to be highly expressed in HGSOC tissue samples and in the patient-derived HGSOC cell lines where higher HDAC6 protein and gene expression was associated with a decreased risk of death (hazard ratio (HR) 0.38, (95% confidence interval (CI), 0.16-0.88; p = 0.02); HR = 0.88 (95% CI, 0.78-0.99; p = 0.04)). Similarly, the multivariate analysis of HDAC6 protein expression, adjusting for stage, grade, and cytoreduction/cytoreductive surgery was associated with a decreased risk of death (HR = 0.19 (95% CI, 0.06-0.55); p = 0.002). Knock-down of HDAC6 gene expression with siRNA and protein expression with a HDAC6 targeting protein degrader decreased HGSOC cell proliferation, migration, and viability. Conversely, the selective inhibition of HDAC6 with the catalytic domain inhibitor, Ricolinostat (ACY-1215), inhibited HDAC6 deacetylation of α-tubulin, resulting in a sustained accumulation of acetylated α-tubulin up to 24 h in HGSOC cells, did not produce a robust inhibition of HDAC6 protein function. Inhibition of HGSOC cell proliferation by ACY-1215 was only achieved with significantly higher and non-selective doses of ACY-1215. In summary, we demonstrated, for the first time, that HDAC6 over-expression in HGSOC and all ovarian cancers is a favorable prognostic marker. We provide evidence to suggest that inhibition of HDAC6 catalytic activity with first generation HDAC6 inhibitors has limited efficacy as a monotherapy in HGSOC.

FKBPL-based peptide, ALM201, targets angiogenesis and cancer stem cells in ovarian cancer.

BACKGROUND: ALM201 is a therapeutic peptide derived from FKBPL that has previously undergone preclinical and clinical development for oncology indications and has completed a Phase 1a clinical trial in ovarian cancer patients and other advanced solid tumours. METHODS: In vitro, cancer stem cell (CSC) assays in a range of HGSOC cell lines and patient samples, and in vivo tumour initiation, growth delay and limiting dilution assays, were utilised. Mechanisms were determined by using immunohistochemistry, ELISA, qRT-PCR, RNAseq and western blotting. Endogenous FKBPL protein levels were evaluated using tissue microarrays (TMA). RESULTS: ALM201 reduced CSCs in cell lines and primary samples by inducing differentiation. ALM201 treatment of highly vascularised Kuramochi xenografts resulted in tumour growth delay by disruption of angiogenesis and a ten-fold decrease in the CSC population. In contrast, ALM201 failed to elicit a strong antitumour response in non-vascularised OVCAR3 xenografts, due to high levels of IL-6 and vasculogenic mimicry. High endogenous tumour expression of FKBPL was associated with an increased progression-free interval, supporting the protective role of FKBPL in HGSOC. CONCLUSION: FKBPL-based therapy can (i) dually target angiogenesis and CSCs, (ii) target the CD44/STAT3 pathway in tumours and (iii) is effective in highly vascularised HGSOC tumours with low levels of IL-6.

Too MAD or not MAD enough: The duplicitous role of the spindle assembly checkpoint protein MAD2 in cancer.

MAD2 is an intriguing protein, which has been associated with poor survival in cancer. Depending on the organ-specific cancer, either high expression or low expression levels have been correlated with low survival rates in patients. MAD2 is also a marker of contradiction. The normal function of MAD2 is to accumulate at kinetochores and generate a wait signal preventing the cell from progressing to anaphase of the cell cycle until the spindle microtubules have correctly aligned with the kinetochores on each chromosome. This process ensures that sister chromatids segregate correctly into each new daughter cell upon cellular division. Thus, the correct function of MAD2 and this crucial cell cycle checkpoint, the spindle assembly checkpoint (SAC), is essential for faithful replicative cell division, the prevention of chromosomal abnormalities and the development of cancer. Surprisingly when MAD2 is supressed for example through siRNA, this results in the induction of cellular senescence or cell cycle arrest. This is an inherent contradiction as normally the dispersement of MAD2 would signal to a cell that they should proceed to anaphase as spindle microtubules have correctly aligned with each chromatid for cell division. In the inverse setting; a second contradiction, high MAD2 expression in cancer patients generally correlates with abnormal chromosome number. However, in normal cells high expression of MAD2 would limit this by generating a wait signal to prevent the cell from proceeding through the cell cycle. In this review article we aim to make sense of the MADness and review the current knowledge of MAD2 and its role in cancer.

FKBPL and its peptide derivatives inhibit endocrine therapy resistant cancer stem cells and breast cancer metastasis by downregulating DLL4 and Notch4.

BACKGROUND: Optimising breast cancer treatment remains a challenge. Resistance to therapy is a major problem in both ER- and ER+ breast cancer. Tumour recurrence after chemotherapy and/or targeted therapy leads to more aggressive tumours with enhanced metastatic ability. Self-renewing cancer stem cells (CSCs) have been implicated in treatment resistance, recurrence and the development of metastatic disease. METHODS: In this study, we utilised in vitro, in vivo and ex vivo breast cancer models using ER+ MCF-7 and ER- MDA-MB-231 cells, as well as solid and metastatic breast cancer patient samples, to interrogate the effects of FKBPL and its peptide therapeutics on metastasis, endocrine therapy resistant CSCs and DLL4 and Notch4 expression. The effects of FKBPL overexpression or peptide treatment were assessed using a t-test or one-way ANOVA with Dunnett's multiple comparison test. RESULTS: We demonstrated that FKBPL overexpression or treatment with FKBPL-based therapeutics (AD-01, pre-clinical peptide /ALM201, clinical peptide) inhibit i) CSCs in both ER+ and ER- breast cancer, ii) cancer metastasis in a triple negative breast cancer metastasis model and iii) endocrine therapy resistant CSCs in ER+ breast cancer, via modulation of the DLL4 and Notch4 protein and/or mRNA expression. AD-01 was effective at reducing triple negative MDA-MB-231 breast cancer cell migration (n ≥ 3, p < 0.05) and invasion (n ≥ 3, p < 0.001) and this was translated in vivo where AD-01 inhibited breast cancer metastasis in MDA-MB-231-lucD3H1 in vivo model (p < 0.05). In ER+ MCF-7 cells and primary breast tumour samples, we demonstrated that ALM201 inhibits endocrine therapy resistant mammospheres, representative of CSC content (n ≥ 3, p < 0.05). Whilst an in vivo limiting dilution assay, using SCID mice, demonstrated that ALM201 alone or in combination with tamoxifen was very effective at delaying tumour recurrence by 12 (p < 0.05) or 21 days (p < 0.001), respectively, by reducing the number of CSCs. The potential mechanism of action, in addition to CD44, involves downregulation of DLL4 and Notch4. CONCLUSION: This study demonstrates, for the first time, the pre-clinical activity of novel systemic anti-cancer therapeutic peptides, ALM201 and AD-01, in the metastatic setting, and highlights their impact on endocrine therapy resistant CSCs; both areas of unmet clinical need.

BRCA1 and MAD2 Are Coexpressed and Are Prognostic Indicators in Tubo-ovarian High-Grade Serous Carcinoma.

OBJECTIVES: The aim of this study was to investigate the relationship between BRCA1 and mitotic arrest deficiency protein 2 (MAD2) protein expression, as determined by immunohistochemistry, and clinical outcomes in epithelial ovarian carcinoma (EOC). METHODS: A tissue microarray consisting of 94 formalin-fixed paraffin-embedded EOC with fully matched clinicopathological data were immunohistochemically stained with anti-BRCA1 and anti-MAD2 antibodies. The cores were scored in a semiquantitative manner evaluating nuclear staining intensity and extent. Coexpression of BRCA1 and MAD2 was evaluated, and patient survival analyses were undertaken. RESULTS: Coexpression of BRCA1 and MAD2 was assessed in 94 EOC samples, and survival analysis was performed on 65 high-grade serous carcinomas (HGSCs). There was a significant positive correlation between BRCA1 and MAD2 expression in this patient cohort (P < 0.0001). Both low BRCA1 and low MAD2 are independently associated with overall survival because of HGSC. Low coexpression of BRCA1 and MAD2 was also significantly associated with overall survival and was driven by BRCA1 expression. CONCLUSION: BRCA1 and MAD2 expressions are strongly correlated in EOC, but BRCA1 expression remains the stronger prognostic factor in HGSC.

Cisplatin induces the release of extracellular vesicles from ovarian cancer cells that can induce invasiveness and drug resistance in bystander cells.

Ovarian cancer has a poor overall survival that is partly caused by resistance to drugs such as cisplatin. Resistance can be acquired as a result of changes to the tumour or due to altered interactions within the tumour microenvironment. Extracellular vesicles (EVs), small lipid-bound vesicles that are loaded with macromolecular cargo and released by cells, are emerging as mediators of communication in the tumour microenvironment. We previously showed that EVs mediate the bystander effect, a phenomenon in which stressed cells can communicate with neighbouring naive cells leading to various effects including DNA damage; however, the role of EVs released following cisplatin treatment has not been tested. Here we show that treatment of cells with cisplatin led to the release of EVs that could induce invasion and increased resistance when taken up by bystander cells. This coincided with changes in p38 and JNK signalling, suggesting that these pathways may be involved in mediating the effects. We also show that EV uptake inhibitors could prevent this EV-mediated adaptive response and thus sensitize cells in vitro to the effects of cisplatin. Our results suggest that preventing pro-tumourigenic EV cross-talk during chemotherapy is a potential therapeutic target for improving outcome in ovarian cancer patients.This article is part of the discussion meeting issue 'Extracellular vesicles and the tumour microenvironment'.

The association between MAD2 and prognosis in cancer: a systematic review and meta-analyses.

This systematic review and meta-analyses investigates the expression of the cell checkpoint regulator, mitotic arrest deficiency protein 2 (MAD2) in cancerous tissue and examines whether an association exists between MAD2 levels and cancer survival and recurrence. Studies investigating MAD2 expression in cancer tissue utilising immunohistochemistry (IHC) were identified by systematic literature searches of Medline, Embase and Web of Science databases by October 2015. Random effects meta-analyses were performed to generate pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of overall and progression-free survival according to MAD2 expression. Forty-three studies were included in the overall review. In 33 studies investigating MAD2 expression by IHC in cancer tissue, a wide range of expression positivity (11-100%) was reported. Higher MAD2 expression was not associated with an increased risk of all-cause mortality in a range of cancers (pooled HR 1.35, 95% CI 0.97-1.87; P = 0.077, n = 15). However, when ovarian cancer studies were removed, a significant pooled HR of 1.59 for risk of all-cause mortality in other cancer patients with higher expressing MAD2 tumours was evident (95% CI, 1.17-2.17; P = 0.003, n = 12). In contrast, higher MAD2 expression was associated with significant decreased risk of all-cause mortality in ovarian cancer patients (pooled HR = 0.50, 95% CI, 0.25-0.97; P = 0.04, n = 3). In conclusion, with the exception of ovarian cancer, increased MAD2 expression is associated with increased risk of all-cause mortality and recurrence in cancer. For ovarian cancer, reduced levels of MAD2 are associated with poorer outcome. Further studies are critical to assess the clinical utility of a MAD2 IHC biomarker.

The fate of chemoresistance in triple negative breast cancer (TNBC).

BACKGROUND: Treatment options for women presenting with triple negative breast cancer (TNBC) are limited due to the lack of a therapeutic target and as a result, are managed with standard chemotherapy such as paclitaxel (Taxol®). Following chemotherapy, the ideal tumour response is apoptotic cell death. Post-chemotherapy, cells can maintain viability by undergoing viable cellular responses such as cellular senescence, generating secretomes which can directly enhance the malignant phenotype. SCOPE OF REVIEW: How tumour cells retain viability in response to chemotherapeutic engagement is discussed. In addition we discuss the implications of this retained tumour cell viability in the context of the development of recurrent and metastatic TNBC disease. Current adjuvant and neo-adjuvant treatments available and the novel potential therapies that are being researched are also reviewed. MAJOR CONCLUSIONS: Cellular senescence and cytoprotective autophagy are potential mechanisms of chemoresistance in TNBC. These two non-apoptotic outcomes in response to chemotherapy are inextricably linked and are neglected outcomes of investigation in the chemotherapeutic arena. Cellular fate assessments may therefore have the potential to predict TNBC patient outcome. GENERAL SIGNIFICANCE: Focusing on the fact that cancer cells can bypass the desired cellular apoptotic response to chemotherapy through cellular senescence and cytoprotective autophagy will highlight the importance of targeting non-apoptotic survival pathways to enhance chemotherapeutic efficacy.

FKBPL: a marker of good prognosis in breast cancer.

FK506-binding protein-like (FKBPL) has established roles as an anti-tumor protein, with a therapeutic peptide based on this protein, ALM201, shortly entering phase I/II clinical trials. Here, we evaluated FKBPL's prognostic ability in primary breast cancer tissue, represented on tissue microarrays (TMA) from 3277 women recruited into five independent retrospective studies, using immunohistochemistry (IHC). In a meta-analysis, FKBPL levels were a significant predictor of BCSS; low FKBPL levels indicated poorer breast cancer specific survival (BCSS) (hazard ratio (HR) = 1.30, 95% confidence interval (CI) 1.14-1.49, p < 0.001). The prognostic impact of FKBPL remained significant after adjusting for other known prognostic factors (HR = 1.25, 95% CI 1.07-1.45, p = 0.004). For the sub-groups of 2365 estrogen receptor (ER) positive patients and 1649 tamoxifen treated patients, FKBPL was significantly associated with BCSS (HR = 1.34, 95% CI 1.13-1.58, p < 0.001, and HR = 1.25, 95% CI 1.04-1.49, p = 0.02, respectively). A univariate analysis revealed that FKBPL was also a significant predictor of relapse free interval (RFI) within the ER positive patient group, but it was only borderline significant within the smaller tamoxifen treated patient group (HR = 1.32 95% CI 1.05-1.65, p = 0.02 and HR = 1.23 95% CI 0.99-1.54, p = 0.06, respectively). The data suggests a role for FKBPL as a prognostic factor for BCSS, with the potential to be routinely evaluated within the clinic.

Overexpression of the microRNA miR-433 promotes resistance to paclitaxel through the induction of cellular senescence in ovarian cancer cells.

Annually, ovarian cancer (OC) affects 240,000 women worldwide and is the most lethal gynecological malignancy. High-grade serous OC (HGSOC) is the most common and aggressive OC subtype, characterized by widespread genome changes and chromosomal instability and is consequently poorly responsive to chemotherapy treatment. The objective of this study was to investigate the role of the microRNA miR-433 in the cellular response of OC cells to paclitaxel treatment. We show that stable miR-433 expression in A2780 OC cells results in the induction of cellular senescence demonstrated by morphological changes, downregulation of phosphorylated retinoblastoma (p-Rb), and an increase in ß-galactosidase activity. Furthermore, in silico analysis identified four possible miR-433 target genes associated with cellular senescence: cyclin-dependent kinase 6 (CDK6), MAPK14, E2F3, and CDKN2A. Mechanistically, we demonstrate that downregulation of p-Rb is attributable to a miR-433-dependent downregulation of CDK6, establishing it as a novel miR-433 associated gene. Interestingly, we show that high miR-433 expressing cells release miR-433 into the growth media via exosomes which in turn can induce a senescence bystander effect. Furthermore, in relation to a chemotherapeutic response, quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that only PEO1 and PEO4 OC cells with the highest miR-433 expression survive paclitaxel treatment. Our data highlight how the aberrant expression of miR-433 can adversely affect intracellular signaling to mediate chemoresistance in OC cells by driving cellular senescence.

IHG-1 increases mitochondrial fusion and bioenergetic function.

Induced in high glucose-1 (IHG-1) is a conserved mitochondrial protein associated with diabetic nephropathy (DN) that amplifies profibrotic transforming growth factor (TGF)-ß1 signaling and increases mitochondrial biogenesis. Here we report that inhibition of endogenous IHG-1 expression results in reduced mitochondrial respiratory capacity, ATP production, and mitochondrial fusion. Conversely, overexpression of IHG-1 leads to increased mitochondrial fusion and also protects cells from reactive oxygen species-induced apoptosis. IHG-1 forms complexes with known mediators of mitochondrial fusion-mitofusins (Mfns) 1 and 2-and enhances the GTP-binding capacity of Mfn2, suggesting that IHG-1 acts as a guanine nucleotide exchange factor. IHG-1 must be localized to mitochondria to interact with Mfn1 and Mfn2, and this interaction is necessary for increased IHG-1-mediated mitochondrial fusion. Together, these findings indicate that IHG-1 is a novel regulator of both mitochondrial dynamics and bioenergetic function and contributes to cell survival following oxidant stress. We propose that in diabetic kidney disease increased IHG-1 expression protects cell viability and enhances the actions of TGF-ß, leading to renal proximal tubule dedifferentiation, an important event in the pathogenesis of this devastating condition.

Spindle assembly checkpoint protein expression correlates with cellular proliferation and shorter time to recurrence in ovarian cancer.

Ovarian carcinoma (OC) is the most lethal of the gynecological malignancies, often presenting at an advanced stage. Treatment is hampered by high levels of drug resistance. The taxanes are microtubule stabilizing agents, used as first-line agents in the treatment of OC that exert their apoptotic effects through the spindle assembly checkpoint. BUB1-related protein kinase (BUBR1) and mitotic arrest deficient 2 (MAD2), essential spindle assembly checkpoint components, play a key role in response to taxanes. BUBR1, MAD2, and Ki-67 were assessed on an OC tissue microarray platform representing 72 OC tumors of varying histologic subtypes. Sixty-one of these patients received paclitaxel and platinum agents combined; 11 received platinum alone. Overall survival was available for all 72 patients, whereas recurrence-free survival (RFS) was available for 66 patients. Increased BUBR1 expression was seen in serous carcinomas, compared with other histologies (P = .03). Increased BUBR1 was significantly associated with tumors of advanced stage (P = .05). Increased MAD2 and BUBR1 expression also correlated with increased cellular proliferation (P < .0002 and P = .02, respectively). Reduced MAD2 nuclear intensity was associated with a shorter RFS (P = .03), in ovarian tumors of differing histologic subtype (n = 66). In this subgroup, for those women who received paclitaxel and platinum agents combined (n = 57), reduced MAD2 intensity also identified women with a shorter RFS (P < .007). For the entire cohort of patients, irrespective of histologic subtype or treatment, MAD2 nuclear intensity retained independent significance in a multivariate model, with tumors showing reduced nuclear MAD2 intensity identifying patients with a poorer RFS (P = .05).

IHG-1 must be localised to mitochondria to decrease Smad7 expression and amplify TGF-ß1-induced fibrotic responses.

TGF-ß1 is a prototypic profibrotic cytokine and major driver of fibrosis in the kidney and other organs. Induced in high glucose-1 (IHG-1) is a mitochondrial protein which we have recently reported to be associated with renal disease. IHG-1 amplifies responses to TGF-ß1 and regulates mitochondrial biogenesis by stabilising the transcriptional co-activator peroxisome proliferator-activated receptor gamma coactivator-1-alpha. Here we report that the mitochondrial localisation of IHG-1 is pivotal in the amplification of TGF-ß1 signalling. We demonstrate that IHG-1 expression is associated with repression of the endogenous TGF-ß1 inhibitor Smad7. Intriguingly, expression of a non-mitochondrial deletion mutant of IHG-1 (Δmts-IHG-1) repressed TGF-ß1 fibrotic signalling in renal epithelial cells. In cells expressing Δmts-IHG-1 fibrotic responses including CCN2/connective tissue growth factor, fibronectin and jagged-1 expression were reduced following stimulation with TGF-ß1. Δmts-IHG-1 modulation of TGF-ß1 signalling was associated with increased Smad7 protein expression. Δmts-IHG-1 modulated TGF-ß1 activity by increasing Smad7 protein expression as it failed to inhibit TGF-ß1 transcriptional responses when endogenous Smad7 expression was knocked down. These data indicate that mitochondria modulate TGF-ß1 signal transduction and that IHG-1 is a key player in this modulation.

Low MAD2 expression levels associate with reduced progression-free survival in patients with high-grade serous epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) has an innate susceptibility to become chemoresistant. Up to 30% of patients do not respond to conventional chemotherapy [paclitaxel (Taxol®) in combination with carboplatin] and, of those who have an initial response, many patients relapse. Therefore, an understanding of the molecular mechanisms that regulate cellular chemotherapeutic responses in EOC cells has the potential to impact significantly on patient outcome. The mitotic arrest deficiency protein 2 (MAD2), is a centrally important mediator of the cellular response to paclitaxel. MAD2 immunohistochemical analysis was performed on 82 high-grade serous EOC samples. A multivariate Cox regression analysis of nuclear MAD2 IHC intensity adjusting for stage, tumour grade and optimum surgical debulking revealed that low MAD2 IHC staining intensity was significantly associated with reduced progression-free survival (PFS) (p = 0.0003), with a hazard ratio of 4.689. The in vitro analyses of five ovarian cancer cell lines demonstrated that cells with low MAD2 expression were less sensitive to paclitaxel. Furthermore, paclitaxel-induced activation of the spindle assembly checkpoint (SAC) and apoptotic cell death was abrogated in cells transfected with MAD2 siRNA. In silico analysis identified a miR-433 binding domain in the MAD2 3' UTR, which was verified in a series of experiments. Firstly, MAD2 protein expression levels were down-regulated in pre-miR-433 transfected A2780 cells. Secondly, pre-miR-433 suppressed the activity of a reporter construct containing the 3'-UTR of MAD2. Thirdly, blocking miR-433 binding to the MAD2 3' UTR protected MAD2 from miR-433 induced protein down-regulation. Importantly, reduced MAD2 protein expression in pre-miR-433-transfected A2780 cells rendered these cells less sensitive to paclitaxel. In conclusion, loss of MAD2 protein expression results in increased resistance to paclitaxel in EOC cells. Measuring MAD2 IHC staining intensity may predict paclitaxel responses in women presenting with high-grade serous EOC.

IHG-1 promotes mitochondrial biogenesis by stabilizing PGC-1α.

Increased expression of Induced-by-High-Glucose 1 (IHG-1) associates with tubulointerstitial fibrosis in diabetic nephropathy. IHG-1 amplifies TGF-ß1 signaling, but the functions of this highly-conserved protein are not well understood. IHG-1 contains a putative mitochondrial-localization domain, and here we report that IHG-1 is specifically localized to mitochondria. IHG-1 overexpression increased mitochondrial mass and stabilized peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). Conversely, inhibition of IHG-1 expression decreased mitochondrial mass, downregulated mitochondrial proteins, and PGC-1α-regulated transcription factors, including nuclear respiratory factor 1 and mitochondrial transcription factor A (TFAM), and reduced activity of the TFAM promoter. In the unilateral ureteral obstruction model, we observed higher PGC-1α protein expression and IHG-1 levels with fibrosis. In a gene-expression database, we noted that renal biopsies of human diabetic nephropathy demonstrated higher expression of genes encoding key mitochondrial proteins, including cytochrome c and manganese superoxide dismutase, compared with control biopsies. In summary, these data suggest that IHG-1 increases mitochondrial biogenesis by promoting PGC-1α-dependent processes, potentially contributing to the pathogenesis of renal fibrosis.

MAD2 downregulation in hypoxia is independent of promoter hypermethylation.

Aberrant expression of the MAD2 protein has been linked to chromosomal instability, malignant transformation and chemoresistance. Although reduced MAD2 expression is well recognised in human cancer cell lines, the mechanism(s) underlying its downregulation remain elusive. The objective of this study was to establish the impact of hypoxia on MAD2 expression and to investigate the potential role of aberrant promoter methylation as a possible mechanism of MAD2 downregulation. For this purpose, three ovarian cancer cell lines, displaying differing levels of MAD2, were treated with chromatin modifying drugs, pre and post-hypoxia exposure and a DHPLC analysis of DNA promoter methylation carried out. We show that hypoxia induces downregulation of MAD2 expression, independently of MAD2 promoter methylation. We also show no evidence of MAD2 promoter methylation in breast and prostate cancer cells or in breast cancer clinical material. While our findings provide no evidence for MAD2 promoter methylation, we show a concomitant upregulation of p21 with downregulation of MAD2 in hypoxia. Our in vitro results were also confirmed in an ovarian cancer tissue microarray (TMA), where a reciprocal staining of MAD2 and CAIX was found in 21/60 (35%) of tumours. In summary, MAD2 downregulation may be a crucial mechanism by which hypoxic cells become chemorefractory. This stems from our previous work where we demonstrated that MAD2 downregulation induces cellular senescence, a viable cellular fate, with resultant cellular resistance to paclitaxel. Moreover, MAD2 downregulation could play a central role in the induction of chemoresistance in hypoxia, a key tumour microenvironment associated with chemoresistance.

Recurrence of urothelial carcinoma of the bladder: a role for insulin-like growth factor-II loss of imprinting and cytoplasmic E-cadherin immunolocalization.

PURPOSE: This study documents the frequency of insulin-like growth factor-II (IGF-II) loss of imprinting (LOI) in a series of 87 bladder tissues. E-cadherin (CDH1) immunolocalization was also investigated due to the known redistribution of this adherence protein to the cytoplasm following exogenous exposure to IGF-II. EXPERIMENTAL DESIGN: Informative IGF-II cases were identified following DNA-PCR amplification and subsequent sequencing of the transcribable ApaI RFLP in exon 9 of IGF-II. Similar approaches using primer-specific cDNA templates identified the imprinting status of IGF-II in these informative cases. CDH1 cellular localization was assessed on a tissue microarray platform of 114 urothelial carcinoma of the bladder (UCB) cases (70 pT(a) noninvasive and 44 pT(1) lamina propria invasive) using the commercially available Novocastra antibody. RESULTS: IGF-II LOI was evident in 7 of 17 (41%) UCB tumors and 4 of 11 (36%) tumor-associated normal urothelial samples. Two of four pT(1) grade 3 tumors, the subject of much debate concerning their suitability for radical cystectomy, showed LOI at the IGF-II locus. In those tumors showing IGF-II LOI, 4 of 7 (57%) displayed concomitant CDH1 cytoplasmic staining. In contrast, only 3 of 10 (30%) IGF-II maintenance of imprinting tumors had concomitant CDH1 cytoplasmic localization. UCB cell lines displaying cytoplasmic CDH1 immunolocalization expressed significantly higher levels of IGF-II (CAL29, HT1376, and RT112) compared with RT4, a cell line displaying crisp membranous CDH1 staining. Finally, cytoplasmic CDH1 staining was an independent predictor of a shorter time to recurrence independent of tumor grade and stage. CONCLUSIONS: We suggest that CDH1 cytoplasmic immunolocalization as a result of increased IGF-II levels identifies those nonmuscle invasive presentations most likely to recur and therefore might benefit from more radical nonconserving bladder surgery.