Abstract 942: CYP3A4 epoxygenase mediates hypoxia-induced biosynthesis of epoxyeicosatrienoic acids (±)-11,12- and (±)-14,15-EET in breast cancer cells

Introduction: CYP3A4 has recently been implicated in the growth of breast cancer cell proliferation but whether it promotes cell proliferation under conditions of hypoxia is unknown. This autocrine/paracrine growth promoting mechanism is dependent on epoxygenase activity, requires epoxygenation of arachidonic acid and can be complemented by add back of (±)-14,15-EET. Ambient tissue oxygen concentrations in tumors range from sub-microM to 50 microM. Methods: Human recombinant CYP3A4 SupersomesTM(BD Bioscience)-catalyzed epoxygenation of arachidonic acid (AA, 100 μM) reaction was performed at 37°C in the presence of a NADPH regenerating system. Oxygen concentration of the reaction solution was varied and rates of oxygen consumption were recorded with an oxygen electrode. Lineweaver Burke analysis was performed to calculate the oxygen Michaelis-Menten constant (Km). MCF7 breast cancer lines stably expressing two different CYP3A4 shRNA expression constructs were exposed to hypoxic conditions ([O2]=50 μM) and EET levels were quantified. Results: The oxygen Km for CYP3A4 was 21 μM. Under hypoxic incubation ([O2]=50 μM), (±)-8,9-EET levels were unaffected but (±)-11,12-EET and (±)-14,15-EET levels were induced 1.5 and 1.3-fold (P<0.05; Student t-test). The MCF7 CYP3A4 knock down line 3-18 line, which exhibits 80% knock down of CYP3A4, exhibited no response to hypoxia compared to the MCF7 non-target (NT) line, which exhibited 1.25 and 1.33 fold increase of (±)-11,12- and (±)-14,15-EET respectively. Remarkably, (±)-8,9-EET exhibited no induction under hypoxic conditions. Conclusions: These results indicate that CYP3A4, which is known to promote breast cancer cell proliferation, is responsive to oxygen under ambient conditions comparable to those found in hypoxic tissues, exhibiting a Km of 21 μM. These results also indicate that hypoxia induces EETs in the breast cancer line, in a fashion dependent on CYP3A4. CYP3A4 therefore provides the majority of EETs induced in breast cancer cells under conditions of hypoxia and may contribute to autocrine and paracrine breast cancer growth signals under these conditions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 942. doi:1538-7445.AM2012-942

Cyp2c44 epoxygenase is essential for preventing the renal sodium absorption during increasing dietary potassium intake

The aim of this study is to test whether the Cyp2c44 epoxygenase-dependent metabolism of arachidonic acid prevents the hypertensive effect of a high K (HK) intake by inhibiting the epithelial sodium channel (ENaC) activity. A HK intake elevated Cyp2c44 mRNA expression and 11,12-epoxyeicosatrienoic acid levels in the cortical collecting duct in Cyp2c44(+/+) mice (wild-type [wt]). However, an HK intake failed to increase 11,12-epoxyeicosatrienoic acid formation in the cortical collecting ducts of Cyp2c44(-/-) mice. Moreover, increasing K intake enhanced arachidonic acid-induced inhibition of ENaC in the wt but not in Cyp2c44(-/-) mice. In contrast, 11,12-epoxyeicosatrienoic acid, a Cyp2c44 metabolite, inhibited ENaC in the wt and Cyp2c44(-/-) mice. The notion that Cyp2c44 is the epoxygenase responsible for mediating the inhibitory effects of arachidonic acid on ENaC is further suggested by the observation that inhibiting Cyp-epoxygenase increased the whole-cell Na currents in principal cells of wt but not in Cyp2c44(-/-) mice. Feeding mice with an HK diet raised the systemic blood pressures of Cyp2c44(-/-) mice but was without an effect on wt mice. Moreover, application of amiloride abolished the HK-induced hypertension in Cyp2c44(-/-) mice. The HK-induced hypertension of Cyp2c44(-/-) mice was accompanied by decreasing 24-hour urinary Na excretion and increasing the plasma Na concentration, and the effects were absent in wt mice. In contrast, disruption of the Cyp2c44 gene did not alter K excretion. We conclude that Cyp2c44 epoxygenase mediates the inhibitory effect of arachidonic acid on ENaC and that Cyp2c44 functions as an HK-inducible antihypertensive enzyme responsible for inhibiting ENaC activity and Na absorption in the aldosterone-sensitive distal nephron.

Recommendations and expert opinion on the treatment of locally advanced rectal cancer in Spain

In Spain 22,000 new cases of colorectal cancer are diagnosed each year, with 13,075 deaths resulting from this disease. Around 70% of colorectal cancers are localised in the colon and 30% in the rectum. A group of Spanish experts established recommendations on what would be the best strategy in the treatment of locally advanced rectal cancer (LARC). Adequate assessment of local tumour extension, including high-resolution magnetic resonance imaging and endorectal ultrasound, is essential for successful treatment. The three cornerstones in the treatment of LARC are surgery, radiotherapy and chemotherapy. Most patients will need a total mesorectal excision (TME). Preoperative chemo-radiotherapy (CRT) is preferred for the majority of patients with T3/T4 disease and/or regional node involvement, and adjuvant chemotherapy is recommended after a patient-sharing decision. Capecitabine, after showing a trend in improved downstaging in neoadjuvant stratum and the convenience of its oral administration, represents an alternative to 5-FU as perioperative treatment of LARC.

Abstract 357: CYP3A4 Activates Stat3 in ER + breast cancer

CYP3A4 expression in breast cancer has been reported to correlate with nodal metastases and decreased overall survival, but its mechanisms in cancer progression are unknown. ERalpha has been reported to promote CYP3A4 expression. We have previously demonstrated that CYP3A4 is an arachidonic acid (AA) epoxygenase that activates breast cancer cell proliferation through biosynthesis of 14,15-epoxyeicosatrienoic acid (EET).

Methods: Effects of 14,15-EET on Stat3 regulation were studied in MCF7 lines expressing CYP3A4 shRNA. Quantitative immunofluorescence (AQUA) interrogation of a tissue microarray was performed to evaluate CYP3A4 in cytoplasm, ERalpha and pY705Stat3 (pYStat3) in nuclei, and HER2 in cytoplasm/membrane. Values were transformed using the natural logarithm. These values were then averaged across the two spot sets. Pearson's correlation was calculated between the markers of interest.

Results: Stat3 (Tyr 705) phosphorylation is inhibited by CYP3A4 silencing. CYP3A4 synthesizes 14,15-EET in breast cancer cells and silencing of Stat3 blocks breast cancer cell growth and abrogates 14,15-EET-induced proliferation, indicating that CYP3A4 requires 14,15-EET biosynthesis and Stat3 to induce cell growth. Silencing of CYP3A4 reduces nuclear pY705-Stat3, while 14,15-EET restores this signaling process. By preliminary immunofluorescence study of consecutive breast cancers (n=48) nuclear ERalpha was associated with cytoplasmic CYP3A4 with a correlation of r=0.7575 (p-value < 0.0001). Cytoplasmic CYP3A4 correlated with nuclear pYStat3, with a correlation of r=0.2708, approaching statistical significance (p = 0.0656). Cytoplasmic/membrane HER2, known to be induced by Stat3, was associated with nuclear pYStat3, exhibiting a correlation of r=0.4460 (p-value = 0.0015).

Conclusions: ER+ breast cancer cell growth is therefore mediated, in part, by CYP3A4 biosynthesis of 14,15-EET that induces nuclear pY705-Stat3. These studies indicate that CYP3A4 is an AA epoxygenase that is expressed in ER+ breast cancer and promotes Stat3-mediated breast cancer cell growth, in part, through 14,15-EET biosynthesis. Activated Stat3 may mediate cytoplasmic/membrane HER2 expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 357. doi:10.1158/1538-7445.AM2011-357

CYP3A4 mediates growth of estrogen receptor-positive breast cancer cells in part by inducing nuclear translocation of phospho-Stat3 through biosynthesis of (±)-14,15-epoxyeicosatrienoic acid (EET)

CYP3A4 expression in breast cancer correlates with decreased overall survival, but the mechanisms are unknown. Cytochrome P450 gene profiling by RNAi silencing demonstrates that CYP3A or 2C8 gene expression is specifically required for growth of the breast cancer lines MCF7, T47D, and MDA-MB-231. CYP3A4 silencing blocks the cell cycle at the G(2)/M checkpoint and induces apoptosis in the MCF7 line, thereby inhibiting anchorage-dependent growth and survival. CYP3A4 was profiled for NADPH-dependent arachidonic acid (AA) metabolism and synthesized AA epoxygenase products (±)-8,9-, (±)-11,12-, and (±)-14,15-epoxyeicosatrienoic acid (EET) (total turnover of ∼2 pmol/pmol CYP3A4/min) but not hydroxylase products (±)-15-, (±)-19-, or 20-hydroxyeicosatetraenoic acid. Furthermore, eicosanoid profiling revealed that MCF7 cells synthesize EETs in a CYP3A4-dependent manner. The (±)-14,15-EET regioisomer selectively rescues breast cancer cells from CYP3A4 silencing in a concentration-dependent fashion and promotes mitogenesis and anchorage-dependent cloning. Stat3 (Tyr-705) phosphorylation was inhibited by CYP3A4 silencing, providing a potential mechanism for CYP3A4 involvement in breast cancer cell growth. Silencing Stat3 blocks breast cancer cell growth and abrogates (±)-14,15-EET-induced proliferation, indicating a Stat3 requirement for (±)-14,15-EET-mediated cell growth. Although silencing of CYP3A4 reduces nuclear Tyr(P)-705-Stat3, (±)-14,15-EET restores this signaling process and promotes Tyr(P)-705-Stat3 translocation to the nucleus, suggesting that (±)-14,15-EET may be involved in an autocrine/paracrine pathway driving cell growth. These studies indicate that CYP3A4 is a highly active AA epoxygenase that promotes Stat3-mediated breast cancer cell growth in part through (±)-14,15-EET biosynthesis. Furthermore, these studies indicate an essential role for Stat3 as a mediator of epoxygenase activity in breast cancer.

Management by objectives and its impact on specialist prescription quality at discharge and in external consultations

OBJECTIVE

To verify that implementing a policy of management by objectives, based on collaboration between hospital pharmacy, primary care and specialised medical managers, improves prescription quality indicators in specialised care and reduces unwanted "induced" prescriptions (i.e. those issued by specialists, hospital doctors or the patients themselves) in primary care.

METHOD

A four year quasi-experimental controlled intervention study on prescription at discharge and in outpatient hospital consultations was conducted. In hospital A, a quality cycle was applied: assessment, identifying improvement opportunities, implementing corrective actions and re-assessment. However, it was not applied in control hospital B. The indicators chosen were the percentage of generic medicines prescribed, the percentage of prescriptions for new therapies with no added value and the percentage of prescriptions for ACE inhibitors recommended.

RESULTS

In hospital A, an increase in indicators 1 and 3 has been observed, both being statistically significant, between the last year of intervention and the year previous to intervention. Hospital A managed to reduce indicator 2 to 4.5%, while this indicator increased in hospital B to 8.8%. Furthermore, a statistically significant difference in indicators between the two hospitals has been registered.

CONCLUSION

Pay-for-Performance programs in prescription practices of hospital physicians are effective actions to improve quality indicators of medication use.

Phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of HDM-2 antagonist JNJ-26854165 in patients with advanced refractory solid tumors

3514

Background: JNJ-26854165 is a novel first-in-clinic oral Human Double Minute-2 (HDM-2) ubiquitin ligase antagonist. It increases the level of HDM-2 client proteins (e.g. p53) by inhibiting the association of HDM-2-client protein complex with the proteosome. Preclinical studies have demonstrated potent anti-proliferative and apoptosis-inducing activity of JNJ-26854165 in a broad range of p53 wild type and mutant tumor models. Methods: A 3+3 dose escalation study with the primary objectives to determine the adverse event (AE) profile, dose limiting toxicities (DLT) and maximum tolerated dose of JNJ-26854165 is ongoing. Secondary objectives include evaluation of PK and PD activity. Eligible patients have ECOG PS≤2 and adequate hematological, renal and hepatic function. JNJ-26854165 is administered orally once daily on a continuous schedule (21-day cycles). Sequential skin and tumor biopsies are taken, and evaluations for HDM-2, p53 and other pathway related markers are performed, including further molecular analyses for HDM-2 activity. Results: 37 pts have been treated at 9 dose levels (DL), 4–300 mg qd. AEs included nausea, vomiting, fatigue, anorexia, insomnia, electrolyte disturbances, liver function tests and creatinine elevations, and asymptomatic QTc prolongation, mostly grade 1–2. A DLT, grade 3 QTcF prolongation, was observed in one patient at DL 9. The patient was asymptomatic and the QTc prolongation recovered after treatment discontinuation. PK data showed dose-proportionality. After dosing at 300 mg, steady state Cmax and AUC0–24h were 2–3 μg/mL and ≈50 μg.h/mL, respectively, well exceeding the expected effective exposure modeled by preclinical studies. PD data showed engagement of the targeted pathway such as dose-dependent p53 upregulation in skin, upregulation of HDM-2 levels in tumors after treatment, and an increase in plasma MIC-1 levels. No objective responses have been observed so far. Conclusions: JNJ-26854165 was well tolerated at doses beyond the expected effective exposure modeled by preclinical studies. PD activity was observed at the 150–300 mg dose levels. The trial continues with cohort expansion at 300 mg. Updated results will be presented.

[Table: see text]

Phase I study of the novel anticancer drug PM00104 as a 24-hour IV infusion every 3 weeks (q3w) in patients (pts) with advanced solid tumors or lymphoma

2568

Background: PM00104 is a novel synthetic alkaloid related to the marine compounds jorumycin and renieramycins. Preliminary preclinical studies suggest changes in cell cycle and DNA binding properties and transcriptional inhibition as main mechanisms of action. PM00104 has shown broad in vitro and in vivo anti-tumor activity (IC50 ≤ 10-8 M) with an acceptable toxicology profile. Methods: The aim of this phase I study was to assess the safety profile, dose-limiting toxicities (DLT), maximum tolerated dose (MTD), recommended dose (RD), pharmacokinetics (PK), relationship between PK and pharmacodynamics (PD) and anti-tumor activity of PM00104 administered as a 24-hour i.v. infusion q3w. Sequential cohorts of 3–6 pts were treated at 133, 266, 400, 800, 900, 1600, 3200, 4000 and 5000 μg/m2. Results: Twenty nine pts have been treated (18 male, 11 female; median age: 59, range: 44–78; ECOG PS ≤2). Five pts developed DLTs: 2 pts at 5000 μg/m2 (grade 4 thrombocytopenia/neutropenia and grade 3 nausea/vomiting in 1 pt; and grade 3 nausea in 1 pt); 1 at 4000 μg/m2 (grade 4 neutropenia/thrombocytopenia and grade 3 asthenia); 1 at 3200 μg/m2 (grade 3 tumor pain) and 1 at 266 μg/m2 (grade 3 transaminase increase). The MTD was reached at 5000 μg/m2 and the RD at 4000 μg/m2. At the RD 6 more pts have been included in order to further evaluate the safety profile and anti-tumor activity. Other adverse events included nausea and vomiting (more frequent at doses ≥800 μg/m2), fatigue, anorexia and diarrhea; most of them being of ≤grade 2 severity. No objective responses were seen but 3 pts with pancreatic adenocarcinoma, hepatocarcinoma and lower esophagus adenocarcinoma presented stable disease lasting >3 months. PM00104 shows a dose-proportional PK profile, the half-life being 20–30 hours and the volume of distribution around 1000 L. Conclusions: PM00104 has shown an acceptable safety profile with signs of anti-tumor activity in pts with advanced malignancies when administered as a 24-hour i.v. infusion q3w. PM00104 is also being evaluated with other administration schedules as monotherapy and in combination with other anti-tumor agents.

[Table: see text]

Induction chemotherapy with paclitaxel plus carboplatin followed by paclitaxel with concurrent radiotherapy in stage IIIB non-small-cell lung cancer (NSCLC) patients: A phase II trial

PURPOSE

We conducted a prospective phase II trial to evaluate the efficacy and toxicity of induction chemotherapy with paclitaxel plus carboplatin followed by concurrent radiotherapy with weekly paclitaxel in stage IIIB non-small-cell lung cancer (NSCLC) patients.

PATIENTS AND METHODS

Patients with stage IIIB NSCLC received two 3-week cycles of paclitaxel 200mg/m(2) combined with carboplatin (target area under the plasma concentration curve (AUC) of 6 mg/ml) followed by weekly paclitaxel 50mg/m(2) concurrently with radiotherapy consisted of 2 Gy daily, 5 days per week (60 Gy total dose in 6 weeks). The median follow-up period was 5 years.

RESULTS

Between March 1999 and January 2002, 21 patients were enrolled and analyzed. Ninety percent of patients completed the planned treatment schedule. The overall response rate was 76% (24% complete response and 52% partial response). The median overall survival time was 15 months and the 1-year, 2-year and 5-year overall survival rates were 57, 33 and 24%, respectively. The disease progression rate at 1 year was 43% and the median progression-free survival was 8 months. During the chemoradiation period, grade 3-4 oesophagitis and pneumonitis were observed in 24 and 14% of patients, respectively.

CONCLUSIONS

Induction chemotherapy with carboplatin and paclitaxel followed by weekly paclitaxel with concurrent radiotherapy was found to be active and tolerable in selected stage IIIB NSCLC patients. Further studies are needed to improve the safety profile and outcome in this setting.