Fatty acid synthase is a metabolic marker of cell proliferation rather than malignancy in ovarian cancer and its precursor cells.

Ovarian cancer (OC) is caused by genetic aberrations in networks that control growth and survival. Importantly, aberrant cancer metabolism interacts with oncogenic signaling providing additional drug targets. Tumors overexpress the lipogenic enzyme fatty acid synthase (FASN) and are inhibited by FASN blockers, whereas normal cells are FASN-negative and FASN-inhibitor-resistant. Here, we demonstrate that this holds true when ovarian/oviductal cells reside in their autochthonous tissues, whereas in culture they express FASN and are FASN-inhibitor-sensitive. Upon subculture, nonmalignant cells cease growth, express senescence-associated ß-galactosidase, lose FASN and become FASN-inhibitor-resistant. Immortalized ovarian/oviductal epithelial cell lines­although resisting senescence­reveal distinct growth activities, which correlate with FASN levels and FASN drug sensitivities. Accordingly, ectopic FASN stimulates growth in these cells. Moreover, FASN levels and lipogenic activities affect cellular lipid composition as demonstrated by thin-layer chromatography. Correlation between proliferation and FASN levels was finally evaluated in cancer cells such as HOC-7, which contain subclones with variable differentiation/senescence and corresponding FASN expression/FASN drug sensitivity. Interestingly, senescent phenotypes can be induced in parental HOC-7 by differentiating agents. In OC cells, FASN drugs induce cell cycle blockade in S and/or G2/M and stimulate apoptosis, whereas in normal cells they only cause cell cycle deceleration without apoptosis. Thus, normal cells, although growth-inhibited, may survive and recover from FASN blockade, whereas malignant cells get extinguished. FASN expression and FASN drug sensitivity are directly linked to cell growth and correlate with transformation/differentiation/senescence only indirectly. FASN is therefore a metabolic marker of cell proliferation rather than a marker of malignancy and is a useful target for future drug development.

Targeting endogenous fatty acid synthesis stimulates the migration of ovarian cancer cells to adipocytes and promotes the transport of fatty acids from adipocytes to cancer cells.

Despite significant advances in oncology, 1 of 108 female patients succumb to ovarian cancer (OC) each year. Improved novel treatments against this aggressive disease would be a major improvement. The growth of OC cells has been demonstrated to be highly dependent on lipids. OC cells are abundantly present in the abdominal cavity and omentum, the main sites of OC expansion. Accordingly, it has been attempted not only to block the hyperactive synthesis of fatty acids (FAs) in cancer cells, but also to disrupt lipid supply. While either strategy has yielded promising results as monotherapy, the induction of resistance pathways diminishing the anticancer effects is yet conceivable. The endogenous regulation of lipid biosynthesis in OC has been extensively studied. However, the role of stromal cells in the modulation of the effects of anti­lipogenic drugs has not yet been well documented. The present study thus examined the interaction between OC cells and associated stromal cells, when de novo FA synthesis was blocked. It has recently been revealed by the authors that when FA are provided to OC cells in monoculture, the lipid deficiency induced by pharmacological inhibition of FA synthase (FASN), the key enzyme of endogenous FA synthesis, cannot be compensated through an increased FA uptake by OC cells. In the present study, OC cells were co­cultured with adipocytes preloaded with fluorescent FA and the effects of FASN­inhibition on OC homing to adipocytes and the transcellular delivery of fluorescent FA from adipocytes to OC cells were examined. The FASN inhibitors, G28UCM and Fasnall, stimulated the spontaneous migration of A2780 OC cells in a concentration­dependent manner and stimulated the transfer of FA from adipocytes to OC cells. Similar effects were observed with all types of adipocytes tested. The models applied in the present study demonstrated that co­cultured cancer­associated adipocytes may attenuate the anticancer effects of FASN inhibitors by attracting tumor cells and by supplying the cells with FA. This lipid­mediated dependency may provide a rationale for the design of new treatment approaches for the treatment of OC.

Pharmacological Inhibition of Lipid Import and Transport Proteins in Ovarian Cancer.

Ovarian cancer (OC) is the most lethal gynecological malignancy with a 5-year survival rate of 49%. This is caused by late diagnosis when cells have already metastasized into the peritoneal cavity and to the omentum. OC progression is dependent on the availability of high-energy lipids/fatty acids (FA) provided by endogenous de novo biosynthesis and/or through import from the microenvironment. The blockade of these processes may thus represent powerful strategies against OC. While this has already been shown for inhibition of FA/lipid biosynthesis, evidence of the role of FA/lipid import/transport is still sparse. Therefore, we treated A2780 and SKOV3 OC cells with inhibitors of the lipid uptake proteins fatty acid translocase/cluster of differentiation 36 (FAT/CD36) and low-density lipoprotein (LDL) receptor (LDLR), as well as intracellular lipid transporters of the fatty acid-binding protein (FABP) family, fatty acid transport protein-2 (FATP2/SLC27A2), and ADP-ribosylation factor 6 (ARF6), which are overexpressed in OC. Proliferation was determined by formazan dye labeling/photometry and cell counting. Cell cycle analysis was performed by propidium iodide (PI) staining, and apoptosis was examined by annexin V/PI and active caspase 3 labeling and flow cytometry. RNA-seq data revealed altered stress and metabolism pathways. Overall, the small molecule inhibitors of lipid handling proteins BMS309403, HTS01037, NAV2729, SB-FI-26, and sulfosuccinimidyl oleate (SSO) caused a drug-specific, dose-/time-dependent inhibition of FA/LDL uptake, associated with reduced proliferation, cell cycle arrest, and apoptosis. Our findings indicate that OC cells are very sensitive to lipid deficiency. This dependency should be exploited for development of novel strategies against OC.

The PI3 kinase/mTOR blocker NVP-BEZ235 overrides resistance against irreversible ErbB inhibitors in breast cancer cells.

Resistance against first and second generation (irreversible) ErbB inhibitors is an unsolved problem in clinical oncology. The purpose of this study was to examine the effects of the irreversible ErbB inhibitors pelitinib and canertinib on growth of breast and ovarian cancer cells. Although in vitro growth-inhibitory effects of both drugs exceeded by far the effects of all reversible ErbB blockers tested (lapatinib, erlotinib, and gefitinib), complete growth inhibition was usually not reached. To define the mechanism of resistance, we examined downstream signaling pathways in drug-exposed cells by Western blot analysis. Although ErbB phosphorylation was reduced by pelitinib and canertinib, activation of the AKT/mTOR pathway remained essentially unaltered in drug-resistant cells. Correspondingly, transfection of tumor cells with constitutively activated AKT was found to promote resistance against all ErbB inhibitors tested, whereas dominant negative AKT reinstalled sensitivity in drug-resistant cells. In a next step, we applied PI3K/AKT/mTOR blockers including the dual PI3K/mTOR kinase inhibitor NVP-BEZ235. These agents were found to cooperate with pelitinib and canertinib in producing in vitro growth inhibition in cancer cells resistant against ErbB-targeting drugs. In conclusion, our data show that ErbB drug-refractory activation of the PI3K/AKT/mTOR pathway plays a crucial role in resistance against classical and second-generation irreversible ErbB inhibitors, and NVP-BEZ235 can override this form of resistance against pelitinib and canertinib.

The Pharmacological or Genetic Blockade of Endogenous De Novo Fatty Acid Synthesis Does Not Increase the Uptake of Exogenous Lipids in Ovarian Cancer Cells.

Ovarian cancer(OC) is a serious threat to women worldwide. Peritoneal dissemination, ascites and omental metastasis are typical features for disease progression, which occurs in a micro-environment that is rich in high-energy lipids. OC cells require high amounts of lipids for survival and growth. Not only do they import lipids from the host, they also produce lipids de novo. Inhibitors of fatty acid(FA) synthase(FASN) - the rate-limiting enzyme of endogenous FA synthesis that is overexpressed in OC - induce growth-arrest and apoptosis, rendering them promising candidates for cancer drug development. However, cancer researchers have long hypothesized that the lipid deficiency caused by FASN inhibition can be circumvented by increasing the uptake of exogenous lipids from the host, which would confer resistance to FASN inhibitors. In contrast to a very recent report in colorectal cancer, we demonstrate in OC cells (A2780, OVCAR3, SKOV3) that neither FASN inhibitors (G28UCM, Fasnall) nor FASN-specific siRNAs can stimulate a relief pathway leading to enhanced uptake of extrinsic FAs or low density lipoproteins (LDLs). Instead, we observed that the growth-arrest due to FASN inhibition or FASN knock-down was associated with significant dose- and time-dependent reduction in the uptake of fluorescently labeled FAs and LDLs. Western blotting showed that the expression of the FA receptor CD36, the LDL receptor(LDLR) and the lipid transport proteins fatty acid binding proteins 1-9 (FABP1-9) was not affected by the treatment. Next, we compared experimental blockade of endogenous lipid production with physiologic depletion of exogenous lipids. Lipid-free media, similar to FASN inhibitors, caused growth-arrest. Although lipid-depleted cells have diminished amounts of CD36, LDLR and FABPs, they can still activate a restorative pathway that causes enhanced import of fluorophore-labeled FAs and LDLs. Overall, our data show that OC cells are strictly lipid-depend and exquisitely sensitive to FASN inhibitors, providing a strong rationale for developing anti-FASN strategies for clinical use against OC.

The prevalence and correlates of adult separation anxiety disorder in an anxiety clinic.

BACKGROUND: Adult separation anxiety disorder (ASAD) has been identified recently, but there is a paucity of data about its prevalence and associated characteristics amongst anxiety patients. This study assessed the prevalence and risk factor profile associated with ASAD in an anxiety clinic. METHODS: Clinical psychologists assigned 520 consecutive patients to DSM-IV adult anxiety subcategories using the SCID. We also measured demographic factors and reports of early separation anxiety (the Separation Anxiety Symptom Inventory and a retrospective diagnosis of childhood separation anxiety disorder). Other self-report measures included the Adult Separation Anxiety Symptom Questionnaire (ASA-27), the Depression, Anxiety, Stress Scales (DASS-21), personality traits measured by the NEO PI-R and the Work and Social Adjustment Scale. These measures were included in three models examining for overall differences and then by gender: Model 1 compared the conventional SCID anxiety subtypes (excluding PTSD and OCD because of insufficient numbers); Model 2 divided the sample into those with and without ASAD; Model 3 compared those with ASAD with the individual anxiety subtypes in the residual group. RESULTS: Patients with ASAD had elevated early separation anxiety scores but this association was unique in females only. Except for social phobia in relation to some comparisons, those with ASAD recorded more severe symptoms of depression, anxiety and stress, higher neuroticism scores, and greater levels of disability. CONCLUSIONS: Patients with ASAD attending an anxiety clinic are highly symptomatic and disabled. The findings have implications for the classification, clinical identification and treatment of adult anxiety disorders.

Membrane disruption, but not metabolic rewiring, is the key mechanism of anticancer-action of FASN-inhibitors: a multi-omics analysis in ovarian cancer.

Fatty-acid(FA)-synthase(FASN) is a druggable lipogenic oncoprotein whose blockade causes metabolic disruption. Whether drug-induced metabolic perturbation is essential for anticancer drug-action, or is just a secondary-maybe even a defence response-is still unclear. To address this, SKOV3 and OVCAR3 ovarian cancer(OC) cell lines with clear cell and serous histology, two main OC subtypes, were exposed to FASN-inhibitor G28UCM. Growth-inhibition was compared with treatment-induced cell-metabolomes, lipidomes, proteomes and kinomes. SKOV3 and OVCAR3 were equally sensitive to low-dose G28UCM, but SKOV3 was more resistant than OVCAR3 to higher concentrations. Metabolite levels generally decreased upon treatment, but individual acylcarnitines, glycerophospholipids, sphingolipids, amino-acids, biogenic amines, and monosaccharides reacted differently. Drug-induced effects on central-carbon-metabolism and oxidative-phosphorylation (OXPHOS) were essentially different in the two cell lines, since drug-naïve SKOV3 are known to prefer glycolysis, while OVCAR3 favour OXPHOS. Moreover, drug-dependent increase of desaturases and polyunsaturated-fatty-acids (PUFAs) were more pronounced in SKOV3 and appear to correlate with G28UCM-tolerance. In contrast, expression and phosphorylation of proteins that control apoptosis, FA synthesis and membrane-related processes (beta-oxidation, membrane-maintenance, transport, translation, signalling and stress-response) were concordantly affected. Overall, membrane-disruption and second-messenger-silencing were crucial for anticancer drug-action, while metabolic-rewiring was only secondary and may support high-dose-FASN-inhibitor-tolerance. These findings may guide future anti-metabolic cancer intervention.

Interaction between fatty acid synthase- and ErbB-systems in ovarian cancer cells.

Fatty acid synthase (FASN) represents a metabolic oncogene. It produces phospholipids for membrane microdomains that accommodate receptor tyrosine kinases including Epidermal Growth Factor-Receptor (EGFR, ErbB1) and ErbB2 (HER2/neu). FASN and ErbBs are overexpressed in ovarian cancer. We examined the effect of FASN and ErbB inhibition on A2780 and SKOV3 ovarian cancer cells. Growth assays reveal that FASN inhibitor C75 sensitizes tumor cells against anti-ErbB drugs (pelitinib [EKB-569], canertinib [CI-1033], erlotinib, cetuximab, matuzumab, trastuzumab) suggesting FASN/ErbB cooperation. qRT-PCR and Western blotting revealed that C75 represses FASN, EGFR, ErbB2, and AKT suggesting that FASN-induced membrane microdomains accommodate/stabilize ErbBs and facilitate AKT recruitment/activation. Our data indicate that AKT is crucial for ErbB/FASN interaction, AKT cross-inhibits ERK and feeds loops that boost FASN and EGFR transcription, and EGFR and ErbB2 must be co-silenced for maximal FASN downregulation. Taken together, interference with FASN and ErbB abrogates their oncogenicity and should be exploited for ovarian cancer treatment.

Adult attachment styles in panic disorder with and without comorbid adult separation anxiety disorder.

OBJECTIVE: Attachment theory suggests that anxious attachment styles are associated with risk to psychiatric disorder, especially anxiety disorders. Separation anxiety would appear to be a core form of anxiety that is associated with anxious attachment. Nevertheless, as yet no research has examined the relationship of attachment styles to adult separation anxiety disorder, a condition that has only recently been fully recognized. METHOD: The Attachment Style Questionnaire was used to examine attachment styles among 83 consecutive anxiety clinic patients diagnosed with panic disorder with agoraphobia and those re-assigned from that category to adult separation anxiety disorder. RESULTS: Dimensional associations showed strong correlations with scales measuring anxious attachment and separation anxiety. Patients assigned to the separation anxiety group scored significantly higher than those in the panic disorder group on the scales of Need for Approval and Preoccupation with Relationships. CONCLUSIONS: The findings finally dispel the notion that separation anxiety and anxious attachment are relevant to panic disorder with agoraphobia, suggesting instead that that constellation is confined to a separate group, namely that of adult separation anxiety disorder. Possible implications for treatment are considered.

Promoting walking as an adjunct intervention to group cognitive behavioral therapy for anxiety disorders--a pilot group randomized trial.

A group randomized trial of adding a home-based walking program to a standard group cognitive behavioral therapy (GCBT+EX) was compared with groups receiving GCBT and educational sessions (GCBT+ED). The study was implemented in an outpatient clinic providing GCBT for clients diagnosed with panic disorder, generalized anxiety disorder or social phobia. Pre- and post-treatment measures included the self-report depression, anxiety, and stress scale (DASS-21) and measures of physical activity. From January 2004 to May 2005, six groups were allocated to GCBT+EX (n=38) and five to GCBT+ED (n=36). Analysis of covariance for completed cases (GCBT+EX, n=21; GCBT+ED, n=20), adjusting for the group design, baseline DASS-21 scores, and anxiety diagnosis showed significant effect for GCBT+EX on depression, anxiety, and stress (regression coefficients=-6.21, -3.41, and -5.14, respectively, p<0.05) compared to the GCBT+ED. The potential of exercise interventions as adjunct to GCBT for anxiety disorder needs to be further explored.

Process evaluation in an intervention designed to promote physical activity among adults with anxiety disorders: evidence of acceptability and adherence.

ISSUE ADDRESSED: To assess the adherence and acceptability of a physical activity program delivered as an adjunct to the usual cognitive behavioural group therapy (CBGT) for adults with anxiety disorders. METHODS: Seventy-three participants with either a generalised anxiety disorder, social phobia or panic disorder were randomised to either exercise-enhanced CBGT (CBGT+EX) or the usual CBGT plus nutrition education (CBGT+ED) group. Physical activity, stress, anxiety, depression were assessed at baseline; session attendance, compliance and satisfaction were assessed during the eight-week intervention. RESULTS: Forty-five per cent of participants achieved the recommended levels of physical activity for health at baseline. The proportions of participants attending group meetings declined over time across both groups. In the intervention groups (CBGT+EX), a slightly higher proportion of participants attended the CBGT session than the physical activity sessions. Individuals with social phobia were significantly more likely than those with panic or generalised anxiety disorder to adhere to the physical activity program. Among the remaining adherers, most reported satisfaction with their skills development and better understanding of the benefits of physical activity. CONCLUSIONS: Time constraints and participants viewing physical activities as irrelevant or detracting them from their psychological treatment are potential factors contributing to low adherence and present as challenges in implementing a physical activity program as adjunctive to psychological treatment. Process evaluation data helped profile participants who adhered or not adhered to the physical activity program and will inform future physical activity promotion to individuals with anxiety disorders.

Multi-level suppression of receptor-PI3K-mTORC1 by fatty acid synthase inhibitors is crucial for their efficacy against ovarian cancer cells.

Receptor-PI3K-mTORC1 signaling and fatty acid synthase (FASN)-regulated lipid biosynthesis harbor numerous drug targets and are molecularly connected. We hypothesize that unraveling the mechanisms of pathway cross-talk will be useful for designing novel co-targeting strategies for ovarian cancer (OC). The impact of receptor-PI3K-mTORC1 onto FASN is already well-characterized. However, reverse actions-from FASN towards receptor-PI3K-mTORC1-are still elusive. We show that FASN-blockade impairs receptor-PI3K-mTORC1 signaling at multiple levels. Thin-layer chromatography and MALDI-MS/MS reveals that FASN-inhibitors (C75, G28UCM) augment polyunsaturated fatty acids and diminish signaling lipids diacylglycerol (DAG) and phosphatidylinositol 3,4,5-trisphosphate (PIP3) in OC cells (SKOV3, OVCAR-3, A2780, HOC-7). Western blotting and micropatterning demonstrate that FASN-blockers impair phosphorylation/expression of EGF-receptor/ERBB/HER and decrease GRB2-EGF-receptor recruitment leading to PI3K-AKT suppression. FASN-inhibitors activate stress response-genes HIF-1α-REDD1 (RTP801/DIG2/DDIT4) and AMPKα causing mTORC1- and S6-repression. We conclude that FASN-inhibitor-mediated blockade of receptor-PI3K-mTORC1 occurs due to a number of distinct but cooperating processes. Moreover, decrease of PI3K-mTORC1 abolishes cross-repression of MEK-ERK causing ERK activation. Consequently, the MEK-inhibitor selumetinib/AZD6244, in contrast to the PI3K/mTOR-inhibitor dactolisib/NVP-BEZ235, increases growth inhibition when given together with a FASN-blocker. We are the first to provide deep insight on how FASN-inhibition blocks ERBB-PI3K-mTORC1 activity at multiple molecular levels. Moreover, our data encourage therapeutic approaches using FASN-antagonists together with MEK-ERK-inhibitors.

Delays in referral of patients with social phobia, panic disorder and generalized anxiety disorder attending a specialist anxiety clinic.

Individuals with anxiety disorders experience substantial delays in obtaining treatment, but little is known about whether people with specific anxiety subcategories are differentially affected. The present study used a modified Encounter Form to examine the cause and length of delays in reaching primary care and specialist services amongst patients with panic disorder (PD/PD-Ag), social phobia (SP), and generalized anxiety disorder (GAD). Participants were 142 consecutive patients attending a specialist anxiety clinic in South Western Sydney. On average, participants with SP took much longer to consult a primary health care provider. Primary care assessments of those with SP often failed to detect anxiety as the key problem, and subsequently, those with SP reported longer delays in reaching specialist care (>9 years). It is not possible to extrapolate the findings to all individuals with SP, as the study was based on specialist service attenders. Nevertheless, the data supports previous findings in suggesting that SP may not be well-recognized as a disorder needing treatment, either by the patient or the primary health care provider. Appropriate educational programs seem warranted to ensure appropriate treatment for this condition.

Characteristics of Vietnamese patients attending an anxiety clinic in Australia and perceptions of the wider Vietnamese community about anxiety.

This article examined the causes underlying low utilization of mental health services by Vietnamese immigrants in Australia. Study 1 examined cases of Vietnamese patients who had attended an anxiety disorders clinic, while Study 2 surveyed Vietnamese people in the community on their knowledge and attitudes towards common mental problems. Results from Study 1 showed that Vietnamese patients had significantly higher attrition rates, and presented with a larger number of nonanxiety disorders than their Australian-born counterparts. Study 2 results indicated that many Vietnamese people did not differentiate clearly between the terms 'stress', 'anxiety' and 'depression'. Additionally, many participants felt that there was a generally negative cultural attitude towards people suffering from these problems and the mental health system itself. These outcomes suggest the importance of education for ethnic communities regarding available mental health facilities and treatments offered, as well as specific information on mental illness to help remove stigma.

HER Specific TKIs Exert Their Antineoplastic Effects on Breast Cancer Cell Lines through the Involvement of STAT5 and JNK.

BACKGROUND: HER-targeted tyrosine kinase inhibitors (TKIs) have demonstrated pro-apoptotic and antiproliferative effects in vitro and in vivo. The exact pathways through which TKIs exert their antineoplastic effects are, however, still not completely understood. METHODS: Using Milliplex assays, we have investigated the effects of the three panHER-TKIs lapatinib, canertinib and afatinib on signal transduction cascade activation in SKBR3, T47D and Jurkat neoplastic cell lines. The growth-inhibitory effect of blockade of HER and of JNK and STAT5 signaling was measured by proliferation- and apoptosis-assays using formazan dye labeling of viable cells, Western blotting for cleaved PARP-1 and immunolabeling for active caspase 3, respectively. RESULTS: All three HER-TKIs clearly inhibited proliferation and increased apoptosis in HER2 overexpressing SKBR3 cells, while their effect was less pronounced on HER2 moderately expressing T47D cells where they exerted only a weak antiproliferative and essentially no pro-apoptotic effect. Remarkably, phosphorylation/activation of JNK and STAT5A/B were inhibited by HER-TKIs only in the sensitive, but not in the resistant cells. In contrast, phosphorylation/activation of ERK/MAPK, STAT3, CREB, p70 S6 kinase, IkBa, and p38 were equally affected by HER-TKIs in both cell lines. Moreover, we demonstrated that direct pharmacological blockade of JNK and STAT5 abrogates cell growth in both HER-TKI-sensitive as well as -resistant breast cancer cells, respectively. CONCLUSION: We have shown that HER-TKIs exert a HER2 expression-dependent anti-cancer effect in breast cancer cell lines. This involves blockade of JNK and STAT5A/B signaling, which have been found to be required for in vitro growth of these cell lines.

Elevated plasma osteoprotegerin levels are associated with venous thrombosis and bleeding in patients with polycythemia vera.

Patients with polycythemia vera (PV) have an increased risk for the development of thrombohemorrhagic complications. The pathogenesis of these complications is still unclear. An important role in vascular disease has recently been attributed to osteoprotegerin (OPG). It has been shown that various tissues of the cardiovascular system produce OPG, and there is growing evidence of an association between elevated serum OPG levels and cardiovascular morbidity. We evaluated if OPG was associated with an increased risk of venous thrombosis or bleeding complications in a cohort of 114 PV patients. The analysis consisted of a retrospective and a prospective part. In the retrospective univariate analysis, a one unit change in OPG caused the odds of venous thrombosis to increase by 40% (p=0.005) and the odds of bleeding to increase by 52% (p=0.001). Multivariate analysis only slightly attenuated the association to 33% (p=0.03) and 37% (p=0.013) for venous thrombosis and bleeding, respectively. OPG was also related to the development of the combined outcome of venous thrombosis and bleeding in the prospective analysis (log-rank-test: p=0.017). This is the first report that links the occurrence of venous thrombosis or bleeding to elevated OPG levels.

Prominin-1 (CD133, AC133) and dipeptidyl-peptidase IV (CD26) are indicators of infinitive growth in colon cancer cells.

Advanced colorectal cancer is characterized by uncontrolled growth and resistance against anti-cancer agents, including ErbB inhibitors. Recent data suggest that cancer stem cells (CSC) are particularly resistant. These cells may reside within a CD133+ fraction of the malignant cells. Using HCT116 cells we explored the role of CD133 and other CSC markers in drug resistance in colon cancer cells. CD133+ cells outnumbered CD133- cells over time in long-term culture. Both populations displayed the KRAS mutation 38G > A and an almost identical target profile, including EGFR/ErbB1, ErbB2, and ErbB4. Microarray analyses and flow cytometry identified CD26 as additional CSC marker co-expressed on CD133+ cells. However, knock-down of CD133 or CD26 did not affect short-term growth of HCT116 cells, and both cell-populations were equally resistant to various targeted drugs except irreversible ErbB inhibitors, which blocked growth and ERK1/2 phosphorylation in CD133- cells more efficiently than in CD133+ cells. Moreover, the MEK inhibitor AS703026 was found to overcome resistance against ErbB blockers in CD133+ cells. Together, CD133 and CD26 are markers of long-term growth and resistance to ErbB blockers in HCT116 cells, which may be mediated by constitutive ERK activity.

Brief report--associations of personality disorder with early separation anxiety in patients with adult separation anxiety disorder.

A recent study has suggested a link between early separation anxiety and personality disorder. It is possible that this relationship is mediated or confounded by the presence of adult separation anxiety disorder (ASAD). In a clinic study of 397 anxiety patients, we found that ASAD patients with heightened early separation anxiety had higher rates of any Cluster C personality disorder compared to ASAD patients without elevated early separation anxiety, and higher rates of any Cluster B or C personality disorder compared to anxiety patients with low early separation anxiety and no ASAD. Although cross-sectional in design, the study supports a direct link between early separation anxiety and some adult personality disorders, irrespective of the type of adult anxiety disorder present, including ASAD.

Blockade of fatty acid synthase induces ubiquitination and degradation of phosphoinositide-3-kinase signaling proteins in ovarian cancer.

Aberrations within the phosphoinositide-3-kinase (PI3K) pathway occur in greater than 45% of ovarian carcinomas. The PI3K cascade transmits signals from ErbB receptors downstream to S6 and 4EBP1, which are involved in protein biosynthesis. Many ovarian carcinomas reveal hyperactivation of ErbB1 (epidermal growth factor receptor) or ErbB2 (HER2/neu). Unfortunately, the benefit of anti-ErbB drugs is yet rather limited in ovarian carcinomas. Thus, novel targeting strategies are needed for ovarian carcinomas. The lipogenic enzyme fatty acid synthase (FASN) is overexpressed in approximately 80% of ovarian carcinomas. It stimulates cell growth and signifies poor prognosis. FASN inhibition impedes (ErbB) membrane receptor signaling and sensitizes cells against anti-ErbB drugs. Here, we show that the FASN inhibitor C75 and FASN-targeting siRNAs abrogate growth, induce apoptosis, and downregulate phosphorylation/expression of the PI3K effectors AKT, mTOR, p70S6K, S6, and 4EBP1. In contrast, FASN inhibition impairs expression but only weakly affects phosphorylation of ERK1/2 mitogen-activated protein kinases in ovarian carcinoma cells. Cycloheximide-mediated blockade of protein translation reveals that C75- or FASN siRNA-induced shutdown of FASN accelerates decomposition of signaling proteins. This effect is caused by C75- or FASN siRNA-dependent stimulation of ubiquitination followed by lysosomal-autophagosomal proteolysis. In contrast, PI3K inhibitor LY294002 blocks phosphorylation but does not reduce expression/stability of PI3K effectors. Forced expression of hyperactive (HA) AKT1, unlike HA-MEK1, impairs the growth-inhibitory action of C75. We provide first evidence that the anticancer action of FASN inhibitors is at least partially mediated by drug-dependent proteolysis of PI3K effectors. FASN is a promising cancer target, whose inhibition not only abrogates lipogenesis, which is indispensable for cancer growth, but also downregulates oncogenic PI3K signaling.

The DNA-binding epidermal growth factor-receptor inhibitor PD153035 and other DNA-intercalating cytotoxic drugs reactivate the expression of the retinoic acid receptor-beta tumor-suppressor gene in breast cancer cells.

We have previously shown that the epidermal growth factor-receptor (EGFR) tyrosine kinase inhibitor PD153035 induces retinoic acid receptor-beta (RAR-beta) expression in malignant cells by mechanisms that are independent of its blocking activity on EGFR (ErbB1) or on any other ErbB receptor (ErbB2, ErbB3, ErbB4). RAR-beta2, one of three human RAR-beta isoforms (RAR-beta1, RAR-beta2, RAR-beta4), is silenced in many tumors and acts as a tumor suppressor. Forced expression of RAR-beta2 reverts the malignant phenotype of RAR-beta2-negative breast cancer cells and reconstitutes retinoid sensitivity in these cells. Here, we demonstrate that the EGFR inhibitor PD153035 specifically induces RAR-beta2, but not the other two isoforms (RAR-beta1, RAR-beta4) in MDA-MB-468 and MDA-MB-453 human breast cancer cells. Induction was seen at the mRNA (reverse transcription-polymerase chain reaction) and protein level (Western analysis). PD153035-mediated induction of RAR-beta2 was associated with synergistic growth inhibition in cells co-treated with PD153035 and all-trans retinoic acid (tRA). Most importantly, PD153035 restored retinoic acid sensitivity in retinoic acid-resistant cells. Our previous work also revealed that PD153035 directly intercalates into the DNA suggesting that changes in the chromatin structure contribute to the RAR-beta2-inducing effect of PD153035. This prompted us to examine the effect of DNA intercalating chemotherapeutic drugs such as doxorubicin, amsacrine, and mitoxantrone on the expression of RAR-beta. Vincristine was used for comparative reasons, because this drug does not target DNA. All four compounds caused dose-dependent growth inhibition in MDA-MB-468 and MDA-MB-453 cells. Interestingly, compounds that directly interact with the DNA (doxorubicin, amsacrine, mitoxantrone) caused a time-dependent up-regulation of the RAR-beta expression in all cell lines examined, whereas the negative control drug vincristine, which causes disruption of microtubule structures, did not stimulate RAR-beta expression. These data further support the notion that induction of the RAR-beta tumor-suppressor gene in cancer cells by PD153035 is mediated at least in part by its DNA intercalating activity.