Uncoupling hypoxia signaling from oxygen sensing in the liver results in hypoketotic hypoglycemic death

As the ultimate electron acceptor in oxidative phosphorylation, oxygen plays a critical role in metabolism. When oxygen levels drop, heterodimeric hypoxia-inducible factor (Hif) transcription factors become active and facilitate adaptation to hypoxia. Hif regulation by oxygen requires the protein von Hippel-Lindau (pVhl) and pVhl disruption results in constitutive Hif activation. The liver is a critical organ for metabolic homeostasis, and Vhl inactivation in hepatocytes results in a Hif-dependent shortening in life span. While albumin-Cre;Vhl^F/F mice develop hepatic steatosis and impaired fatty acid oxidation, the variable penetrance and unpredictable life expectancy has made the cause of death elusive. Using a system in which Vhl is acutely disrupted and a combination of ex vivo liver perfusion studies and in vivo oxygen measurements, we demonstrate that Vhl is essential for mitochondrial respiration in vivo. Adenovirus-Cre mediated acute Vhl disruption in the liver caused death within days. Deprived of pVhl, livers accumulated tryglicerides and circulating ketone and glucose levels dropped. The phenotype was reminiscent of inborn defects in fatty acid oxidation and of fasted PPARα-deficient mice and while death was unaffected by pharmacologic PPARα activation, it was delayed by glucose administration. Ex vivo liver perfusion analyses and acylcarnitine profiles showed mitochondrial impairment and a profound inhibition of liver ketone and glucose production. By contrast, other mitochondrial functions, such as ureagenesis, were unaffected. Oxygen consumption studies revealed a marked suppression of mitochondrial respiration, which, as determined by magnetic resonance oximetry in live mice, was accompanied by a corresponding increase in liver pO₂. Importantly, simultaneous inactivation of Hif-1β suppressed liver steatosis and rescued the mice from death. These data demonstrate that constitutive Hif activation in mice is sufficient to suppress mitochondrial respiration in vivo and that no other pathway exists in the liver that can allow oxygen utilization when Hif is active precluding thereby metabolic collapse.

Associations of fat mass and fat distribution with bone mineral density in pre- and postmenopausal Chinese women

Fat mass (FM) is closely related to bone mineral density (BMD). However, the associations of FM and fat distribution with BMD in pre- and postmenopausal women are still poorly understood. The present study showed android fat mass accumulation after menopause had a negative association with BMD.

INTRODUCTION

FM is closely related to BMD. However, it is unknown whether FM and central fat distribution have different associations with BMD in pre- and postmenopausal women. The study aims to investigate the associations of FM and fat distribution with BMD in pre- and postmenopausal Chinese women.

METHODS

Two hundred sixty premenopausal and 267 postmenopausal women aged 18 to 79 years were analyzed. Lean mass (LM), FM, percent body fat (%BF), android FM, gynoid FM, and total and regional BMD were measured using dual-energy X-ray absorptiometry. Fat distribution was assessed by android to gynoid FM ratio (AOI). Multiple regression analysis was performed to examine the associations of BMD with FM, LM, and AOI.

RESULTS

FM, %BF, android FM, and AOI were significantly higher, whereas total and regional BMD were significantly lower in postmenopausal women (all р < 0.01). In premenopausal women, FM was positively associated with total and regional BMD (all р < 0.05). AOI had no significant association with BMD. In postmenopausal women, FM was significantly associated with total and regional BMD even additionally adjusting for LM (all р < 0.01). AOI had significantly negative association with total, head, arm, and leg BMD (all р < 0.05). The results remained unchanged when replacing FM with %BF.

CONCLUSIONS

There were different associations of FM and fat distribution with BMD in pre- and postmenopausal Chinese women. Increased central body fat had a negative association with BMD. Our findings may have significant implications in the prevention of menopause-related osteoporosis through reducing centralized fat deposition.

Abstract P4-02-20: Plasticity of the ER and HER2 Signaling Networks Results in Compensatory Escape Pathways Contributing to Treatment Resistance

Bidirectional crosstalk between the estrogen receptor (ER) and HER2 has been demonstrated in preclinical model systems. We have previously shown in HER2+ breast cancer cells with low ER that potent HER2- targeted therapy results in ER reactivation that functions as an escape pathway to evade therapeutic inhibition. Here we investigated the role of HER pathway components in resistance to endocrine therapies using UACC812 cells, which are endogenously amplified for HER2. Endocrine resistant (R) derivatives of the UACC812 line were developed through long-term (&gt;6 months) culturing with estrogen deprivation (ED) alone or with 4-OH-tamoxifen (Tam, 10-7M). Endocrine treatment [continued ED, estrogen (E2, 10-9M), Tam (10-7M), or fulvestrant (Ful, 10-7M)] of parental cells slowed cell growth compared to estrogen treatment (P&lt;0.01). EDR and TamR derivatives treated with any of the endocrine therapies, however, exhibited the same growth rates as with estrogen, validating the completely resistant phenotype of our clones. By immunoblot analysis, the resistant derivatives, TamR and EDR, showed a striking and complete loss of ER expression and its downstream gene products including PR, IGF-1R, and IRS-1. In contrast, both resistant lines exhibited significant upregulation of HER pathway components including marked increases in total and phosphorylated (p) EGFR, further upregulation of pHER2, and marked increases in the downstream signaling moieties pMAPK, pAkt, pFAK, pSrc, and pFOXO3a. In contrast, levels of pHER3 were markedly reduced at resistance. Since our in vitro data suggested that ER and HER2 compensate for inhibition of each other's pathways, we next examined whether simultaneous inhibition of both pathways can circumvent the development of resistance in an in vivo xenograft model. Athymic nude mice bearing UACC812 xenografts, established in the presence of E2 supplementation, were randomized to continued E2, endocrine therapies alone (ED, Tam, or Ful), anti-HER2 alone [lapatinib (L), trastuzumab (T), or L+T], or the combination of endocrine and anti-HER2 therapies (ED with L, T, or L+T). We found that tumors were stimulated by E2, as well as by Tam (as a mechanism of de novo resistance), while still being inhibited, though only temporarily (2-3 months), by ED and Ful. Anti-HER2 therapy alone only slowed down (L or T) or stabilized (L+T) tumor growth. In contrast, in the presence of both ED and anti-HER2 therapies, most tumors completely regressed. However, only the potent L+T plus ED regimen achieved continuous long term (&gt;200 days) complete regression in all mice. Our results further illustrate the plasticity of the ER and HER2 pathways and provide additional support for the role of the HER network, especially EGFR, in resistance to endocrine therapy in ER+/HER2+ breast cancer. The data emphasize the need for complete HER blockade for optimal therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-20.

CSF neutrophils are implicated in the development of vasospasm in subarachnoid hemorrhage

BACKGROUND

Cerebral vasospasm is a significant cause of morbidity in patients after aneurysmal subarachnoid hemorrhage (aSAH). There are few effective treatments. The search for new treatments has focused predominantly on dilating cerebral blood vessels. Growing evidence supports a role for inflammation in its pathogenesis but no potential target for intervention has emerged.

METHODS

CSF and clinical information from patients with aSAH were collected. Additionally, tyrosine modifications by stable isotope dilution HPLC with online tandem mass spectrometry were quantified in CSF samples.

RESULTS

We report an association between neutrophil accumulation in the cerebrospinal fluid of patients with aSAH and the development of vasospasm. In particular, CSF neutrophil content of >62% on the third day after aSAH is an independent predictor of the later development of vasospasm (OR 6.8, 95% CI 2.0-23.3, P = 0.002). Further, activity of myeloperoxidase and NADPH oxidase is elevated in aSAH suggesting a role for modification of CSF proteins by reactive oxidant species.

CONCLUSIONS

Neutrophil percentage is an independent predictor of vasospasm in aSAH patients, days prior to its onset suggesting a role of neutrophils in vasospasm. The activity of neutrophil enzymes is also increased suggesting a mechanism for blood vessel damage. Inflammation mediated by neutrophils is a potential target for therapies in vasospasm. More study is necessary to determine the mechanism by which neutrophils damage cerebral blood vessels.

The hepatoprotective effect of hypothermic perfusion of normal saline in period of inflow occlusion of liver in rats

BACKGROUND

Liver damage in hepatic surgery from warm ischemia and reperfusion (I/R), especially in patients with underlying chronic liver disease, is still challenging. We propose a new method of perfusion of the liver by catheterizing the umbilical vein in the period of hepatic inflow occlusion, and evaluate the influence of transfusion of normal saline (NS) on liver injury in a modified I/R rat model.

METHODS

Twenty-eight rats were randomized into four groups (n=7): group I (sham-operated group): no I/R or transfusion; group II (I/R group): I/R + no transfusion; group III (37°C NS group): I/R + transfusion of 37°C NS ; group IV(24°C NS group): I/R + transfusion of 24°C NS. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), as well as lactate dehydrogenase (LDH) were measured in rat serum. Light and electron microscopic examinations were performed on the liver tissues.

RESULTS

Perfusion of 24°C NS in the period of inflow occlusion resulted in significant reductions of liver enzymes levels compared to the I/R alone group and 37°C NS group (P<0.001 and P<0.001, respectively). Histologic evaluation revealed the injury grade to be relatively lower in group IV compared to group II and III (P<0.001 and P<0.001, respectively).

CONCLUSION

This new hypothermic perfusion technique may be very useful in preserving the hepatocytes in hepatic surgery; it is an inexpensive and easy method, which makes it possible to increase its application.

Prognostic value of different B symptoms in upper aerodigestive tract NK/T-cell lymphoma

e19544

Background: Extranodal NK/T-cell lymphoma (ENKL) is a rare disease originated from NK or toxic T cells. ENKL arising from the upper aerodigestive tract (UNKTL) is a newly recognized subtype and commonly presents with B symptoms. This study is to investigate the prognostic value of different B symptoms in UNKTL. Methods: UNKTL cases with detailed clinical, pathological and prognostic data in our center since 2001 to 2007 were retrospectively analyzed with the major study endpoint of overall survival (OS). Central pathological review was performed. Survival curves were estimated by Kaplan-Meier method and tested by Log Rank method. Statistically significant factors in univariate analysis were then included in multivariate analysis. B symptoms were defined as fever, night sweat and weight loss according to the Ann Arbor Cotswolds meeting. The predictive values of survival for each type of B symptoms were studied independently. Results: 172 cases of UNKTL with a median follow-up duration of 27.4 months were included. 45 ladies and 127 gentlemen had a median age of 43 years. 98 cases were Ann Arbor stage I, 54 were stage II and the remaining 20 cases were stage III or IV. About half of the patients present B symptoms: 82 had fever, 5 had night sweat and 6 present weight loss. Totally 18 patients had ECOG PS larger than 1. The 5-year OS rate of the whole group is 41.8%. Patients with persistent fever before treatment indicated a poor outcome in the univariate analysis (p=.033) and its prognostic value was also confirmed by the Cox regression (p=.030) whereas those of night sweat and weight loss were not (p= .960 and .824 respectively). Conclusions: B symptoms were common in UNKTL patients. Our data suggested that only fever among the three types of B symptoms was independent prognostic factor for UNKTL but it still needs further confirmation.

No significant financial relationships to disclose.

Phase I dose-escalation study of thoracic radiotherapy in combination with gefitinib in patients with IIIB/IV non-small cell lung cancer (NCT00497250)

e14581

Background: Cinical studies have confirmed that gefitinib, an EGFR-TKI, is effective for some advanced NSCLC patients. Patients with Asian ethnicity are reported to have a higher response rate with gefitinib monotherapy. However, a higher incidence of interstitial lung disease, sometimes lethal, is also found. The combination of gefitinib and radiotherapy has been observed to have a synergistic, anti-proliferative effect against NSCLC in vitro. This phase I study assessed the safety, clinical feasibility and optimally tolerated regimen (OTR) of this combination in patients with pretreated locally advanced or metastatic (IIIB/IV) NSCLC. Methods: Patients with stage IIIB or selected stage IV, failure of platinum-based chemotherapy regimen NSCLC were eligible. Four Cohorts of eight patients each were planned to be treated with escalating doses from 54 to 60 Gy of conformal or intensity- modulated radiotherapy (2Gy/Fx) administered in combination with gefitinib 250mg daily during RT and 60 days after the completion of RT to determine the OTR. Results: Since June 2007, 2 cohorts, a total of 16 patients, were enrolled and treated: 8 stage IIIB and 8 stage IV; 2 squamous-cell carcinoma and 14 adenocarcinoma; 8 smokers and 8 nonsmokers. Prior-chemotherapy regimen was consisted of NP, GP and TP for a median of 3.5 cycles (range, 1–5). Median follow-up time was seven months. Mean progression-free survival time was 5.2 months (median, 3.9; range, 1.7–12.3). Overall, adverse events were mild to moderate in severity. The most frequent grade 2 events included pneumonitis (31%) and dysphagia (19%). There were one treatment-related grade 3 event, which was nausea, and no grade 4 events. Most of the failure patterns were out-of-field (11/13) and the most common distant metastasis organ was the lungs. Three patients are progression-free to date. Conclusions: Thoracic radiotherapy up to 56 Gy concurrent with gefitinib 250 mg daily was well tolerated and clinically active in this group of pretreated Chinese NSCLC patients, including nonsmokers with adenocarcinoma. Accrual is continuing. Sponsorship: This work was partly supported by Program for New Century Excellent Talents in University (NCET), Ministry of Education.

No significant financial relationships to disclose.

Involved-field radiotherapy for patients with limited small cell lung cancer: Patterns of local-regional failure and feasibility

7554

Background: To investigate the feasibility of the involved-field radiotherapy in patients with limited-stage small cell lung cancer (LSCLC) according to the patterns of local failure, focused on the first local-regional failure. Methods: Two clinical phase II studies for patients with LSCLC treated at our institute between 1997 and 2007 were reviewed. All patients received combined chemotherapy (CHT) with cisplatin and etoposide, and thoracic RT (TRT) was generally delivered sequentially following one to three cycles of CHT and consisted of either 56 Gy in 40 fractions for 4 weeks or 55 Gy in 22 fractions for 4–5 weeks. TRT fields encompassed primary tumor volume (post-CHT) and the involved nodal areas (pre- and post-CHT) without elective node irradiation. The local-regional failure was defined as failure within thoracic cavity and supraclavicular fossa except for pleural effusion, which was then divided into two subtypes: in-field and out-field failure according to the first occurred site in the planning target volume or not. Results: There were 89 patients completed the planed regimen and eligible for evaluating patterns of failure, 54 patients (57%) in 56 Gy cohort and 35 patients(43%) in 55 Gy cohort. The media cycles of CHT were 6 (4–8). The overall survival and local progression-free survival rates for 89 patients at 2 years were 56% and 71%, respectively, with a median survival of 25.6 months. 56 patients (63%) developed distant metastases and 21 patients (24%) developed local-regional failures: 12 in-field and 9 out-field. 8 out of 9 out-field failures occurred in the ipsilateral supraclavicular fossa, and the media duration to the end of TRT was 6 mouths (5–14). Comparing the 56 Gy and 55 Gy cohorts, the rates of any thoracic, in-field and out-field failures were no difference significantly. Conclusions: Thoracic radiotherapy using involved-field technique in patients with LSCLC resulted in a high failure rate of the supraclavicular fossa. Whether improving accuracy for the initial evaluation of clinical stage could reduce out-field failure in supraclavicular fossa need to be investigated.

No significant financial relationships to disclose.