Abstract P5-09-09: ESRP1 and ESRP2 expression in tamoxifen resistance

Background: Current standard of care therapies with antiestrogens targeting estrogen receptor α (ER) signaling improve disease-free survival (DFS) in early-stage of breast cancer. However a significant number of cases exhibit de novo or acquired endocrine resistance and recur. It is thus important to identify novel targets of resistance and select these patients for additional therapeutic options which might include continued/extended hormonal therapy. The Oncotype Dx recurrence score (RS) in current practice predicts the likelihood of distant recurrence in tamoxifen-treated patients with node-negative, ER+ breast cancer. However, Oncotype Dx does not provide the mechanistic basis for endocrine resistance. In this study, we aimed to investigate the impact of two epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) expression on recurrence and endocrine resistance such as tamoxifen of ER+ breast cancer.

Methods: Publicly available gene expression datasets were analyzed for the overexpression of ESRP1 and ESRP2 in breast cancer. To validate the in silico findings for the ESRP1 and ESRP2 expression, we further performed quantitative real-time RT-PCR (qRT-PCR) in a cohort of 60 paraffin-embedded ER-positive node-negative breast carcinomas with low, intermediate, and high (19, 21, and 20 cases, respectively) Oncotype DX scores. To further determine the correlation between endocrine resistance and ESRP1/ESRP2 expression, we evaluated their expression levels in an established in vitro model of ER+/tamoxifen-resistance (MCF7/LCC2: an acquired tamoxifen resistant model of human breast cancer).

Results: Using publicly available breast cancer gene expression datasets, we have identified that overexpression of the epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) correlates with worse prognosis in ER+ significantly, but not in ER- breast cancers. qRT-PCR analysis further revealed that ESRP1 and ESRP2 expressions are positively correlated with high Oncotype Dx scores (P <0.05). In vitro, ESRP1 and ESRP2 levels were increased 7.48-fold (P = 0.008) and 2.98-fold (P = 0.0007) in ERα-positive cells with acquired tamoxifen resistance (MCF-7 LCC2), respectively. Thus, ESRP1 expression was slightly elevated more than ESRP2. Furthermore, both ESRP1 and ESRP2 levels did not change in response to E2 alone or E2 and tamoxifen treatment in combination.

Conclusion: These findings suggest a role for the elevated expression of ESRP1 and ESRP2 in tamoxifen resistance and recurrence of ER+ breast cancer. Further studies are ongoing to determine their mechanistic role in ER+ cancer and methods of targeting ESRP1 & 2.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-09.

Ricci Flow-based Spherical Parameterization and Surface Registration

This paper presents an improved Euclidean Ricci flow method for spherical parameterization. We subsequently invent a scale space processing built upon Ricci energy to extract robust surface features for accurate surface registration. Since our method is based on the proposed Euclidean Ricci flow, it inherits the properties of Ricci flow such as conformality, robustness and intrinsicalness, facilitating efficient and effective surface mapping. Compared with other surface registration methods using curvature or sulci pattern, our method demonstrates a significant improvement for surface registration. In addition, Ricci energy can capture local differences for surface analysis as shown in the experiments and applications.

Hypophosphatemic osteomalacia and renal Fanconi syndrome induced by low-dose adefovir dipivoxil: a case report and literature review suggesting ethnic predisposition

WHAT IS KNOWN AND OBJECTIVE

Adefovir dipivoxil (ADV) is one of the commonly used antiviral agents in the treatment of chronic hepatitis B (CHB) infection. Safety of a daily dose of 10 mg ADV is advocated by the registration trials. We report a case of severe hypophosphatemic osteomalacia and renal Fanconi syndrome induced by low-dose ADV in a CHB-related cirrhosis patient, and discuss the case through a thorough review of other cases reported in the literature.

CASE SUMMARY

A 48-yr-old Chinese man with CHB-related cirrhosis developed severe progressive generalized bone pain and muscle weakness after receiving ADV 10 mg daily for 54 months. The laboratory results showed severe hypophosphatemia and features of proximal renal tubule dysfunction. Imaging studies were consistent with osteomalacia. After discontinuation of ADV, his symptoms resolved, laboratory abnormalities normalized and imaging studies showed improvement. In addition to our case, 12 other patients have been reported to have developed hypophosphatemic osteomalacia induced by low-dose ADV. Most of the reported cases were of subjects of East-Asian ethnicity. After discontinuation or reduction of ADV, serum phosphate level increased and clinical symptoms significantly improved in all cases.

WHAT IS NEW AND CONCLUSION

Hypophosphatemic osteomalacia and renal Fanconi syndrome can be associated with low-dose ADV. Clinicians treating CHB patients with ADV 10 mg daily over long periods of time should be aware of this infrequent but serious complication.

Citalopram enhances neurovascular regeneration and sensorimotor functional recovery after ischemic stroke in mice

Recent clinical trials have demonstrated that treatment with selective serotonin reuptake inhibitors after stroke enhances motor functional recovery; however, the underlying mechanisms remain to be further elucidated. We hypothesized that daily administration of the clinical drug citalopram would produce these functional benefits via enhancing neurovascular repair in the ischemic peri-infarct region. To test this hypothesis, focal ischemic stroke was induced in male C57/B6 mice by permanent ligation of distal branches of the middle cerebral artery to the barrel cortex and 7-min occlusion of the bilateral common carotid arteries. Citalopram (10mg/kg, i.p.) was injected 24h after stroke and daily thereafter. To label proliferating cells, bromo-deoxyuridine was injected daily beginning 3 days after stroke. Immunohistochemical and functional assays were performed to elucidate citalopram-mediated cellular and sensorimotor changes after stroke. Citalopram treatment had no significant effect on infarct formation or edema 3 days after stroke; however, citalopram-treated mice had better functional recovery than saline-treated controls 3 and 14 days after stroke in the adhesive removal test. Increased expression of brain-derived neurotrophic factor was detected in the peri-infarct region 7 days after stroke in citalopram-treated animals. The number of proliferating neural progenitor cells and the distance of neuroblast migration from the sub-ventricular zone toward the ischemic cortex were significantly greater in citalopram-treated mice at 7 days after stroke. Immunohistochemical staining and co-localization analysis showed that citalopram-treated animals generated more new neurons and microvessels in the peri-infarct region 21 and 28 days after stroke. Taken together, these results suggest that citalopram promotes post-stroke sensorimotor recovery likely via enhancing neurogenesis, neural cell migration and the microvessel support in the peri-infarct region of the ischemic brain.

Recombinant human endostatin combined with definitive chemoradiotherapy as primary treatment for patients with unresectable but without systemic metastatic squamous cell carcinoma of the oesophagus

OBJECTIVE

The objective of this study was to review the outcomes of recombinant human endostatin combined with chemoradiotherapy (CRT) as primary treatment for patients with unresectable but without systemic metastatic squamous cell carcinoma (SCC) of the oesophagus.

METHODS

A total of 38 patients with unresectable but without systemic metastatic SCC of the oesophagus (T(4) or stage IVA) were retrospectively studied. 18 patients were treated with recombinant human endostatin combined with 5-fluorouracil (5-FU)/cisplatin (CDDP)-based CRT and 20 were treated with 5-FU/CDDP-based CRT alone. Short- and long-term effects including initial treatment response, survival and treatment-related complications were assessed with a median follow-up period of 36.1 months.

RESULTS

CRT combined with endostatin resulted in a marked improvement in complete response rates (44.4% vs 30% in the CRT-alone group), and an increase in the 1-year and 3-year overall survival rates (72% vs 50.0% and 32% vs 22.0%, respectively), while the median time to progression was extended to 11.3 months in the combination group vs 8.1 months in the CRT-alone group. There were no treatment-related toxicities that could be attributed specifically to the endostatin, and the toxicities observed across the two groups are probably due to the CRT itself.

CONCLUSIONS

The short- and long-term effects of CRT combined with endostatin were an improvement over that of CRT alone in this retrospective cohort study. This combined treatment modality may be a promising treatment modality for the patients with unresectable but without systemic metastatic oesophageal cancer. Further prospective randomised control studies are needed to confirm this finding.

Characterization of surface accumulation and release of nanosilica during irradiation of polymer nanocomposites by ultraviolet light

Polymer nanocomposites are increasingly used in applications that are subjected to harsh environments. Owing to polymer's susceptibility to photodegradation, nanofillers in a polymer nanocomposite may be released into the environments during the composite's life cycle. Such release potentially poses an environmental health and safety problem and may hinder commercialization of these advanced materials. This study investigated the fate and release of nanosilica from epoxy/nanosilica composites. Specially-designed holders containing nanocomposite specimens were irradiated with UV light in a well-controlled environmental chamber. UV irradiated samples were removed for measurements of polymer chemical degradation, mass loss, surface morphology, nanosilica accumulation on the composite surface, and nanosilica release. Epoxy matrix underwent rapid photodegradation, resulting in substantial accumulation of silica nanofillers on the composite surface and also release from the composite. A conceptual model for surface accumulation and release of nanosilica during UV irradiation of epoxy nanocomposites is presented.