Assessment of muscarinic and nicotinic acetylcholine receptor expression in primitive neuroectodermal tumor/ewing family of tumor and desmoplastic small round cell tumor: an immunohistochemical and Western blot study of tissue microarray and cell lines

Akt and Hippo Pathways in Ewing's Sarcoma Tumors and Their Prognostic Significance

Background: Ewing's sarcoma tumor is an aggressive malignancy of bone and soft tissue in children and young adults. Despite advances in modern therapy, metastasis occurs and results in high mortality. Intracellular molecules Yap, Akt, mTOR, and Erk are signaling pathway members that regulate the proliferation of tumor cells.

Objective and Methods: We studied the immunohistochemical expression of these proteins in 36 tumor samples from adult and pediatric patients with Ewing's sarcoma tumors. Patients' age, sex, tumor site, tumor size, clinical stage and survival (overall and disease-free survival) were collected. Tissue microarrays slides were stained with antibodies against Yap, Akt, mTOR, and Erk proteins.

Results: Tumors exhibited variable expression of Yap, Akt, mTOR, and Erk (from negative, low to high), with high levels of expression present in 31%, 53%, 77% and 0% respectively. Immunohistochemical expression of Akt was associated with worse overall and disease-free survival (p<0.05). The other biomarkers did not demonstrate any difference in survival between low versus high expression.

Conclusion: Although Yap, Akt, mTOR, and Erk protein are all expressed in Ewing's sarcoma by immunohistochemistry, only Akt expression is associated with worse prognosis. Larger studies are needed to verify these results and plan targeted therapy, particularly against Akt.

CYP3A isoforms in Ewing's sarcoma tumours: an immunohistochemical study with clinical correlation

Ewing's sarcoma is an aggressive malignancy of bone and soft tissue with high incidence of metastasis and resistance to chemotherapy. Cytochrome P450 (CYP) monooxygenases are a family of enzymes that are involved in the metabolism of exogenous and endogenous compounds, including anti-cancer drugs, and have been implicated in the aggressive behaviour of various malignancies. Tumour samples and clinical information including age, sex, tumour site, tumour size, clinical stage and survival were collected from 36 adult and paediatric patients with Ewing's sarcoma family tumours. Tissue microarrays slides were processed for immunohistochemical labelling for CYP3A4, CYP3A5 and CYP3A7 using liver sections as positive control. The intensity of staining was scored as negative, low or high expression and was analysed statistically for any association with patients' clinical information. Four cases were later excluded due to inadequate viable tissue. CYP3A4 staining was present in 26 (81%) cases with high expression noted in 13 (40%) of 32 cases. High expression was significantly associated with distant metastases (P < 0.05). CYP3A5 and CYP3A7 were expressed in 5 and 13 cases respectively (15.6%, 40.6%). There was no association between the expression of CYP3A isoforms and age, sex, tumour size, or location (pelvic or extra-pelvic). None of the biomarkers showed any correlation with overall or disease-free survival. In conclusion, expression of CYP3A isoforms is noted in Ewing's sarcoma tumours and high CYP3A4 expression may be associated with metastasis. Additional studies are needed to further investigate the role of CYP3A4 in the prognosis of these tumours.

In vivo and in silico pharmacokinetics and biodistribution of a melanocortin receptor 1 targeted agent in preclinical models of melanoma

The melanocortin 1 receptor (MC1R) is overexpressed in most melanoma metastases, making it a promising target for imaging of melanomas. In this study, the expression of MC1R in a large fraction of patients with melanoma was confirmed using mRNA and tissue microarray. Here, we have characterized the in vivo tumor and tissue distribution and pharmacokinetics (PK) of uptake and clearance of a MC1R specific peptidomimetic ligand conjugated to a near-infrared fluorescent dye. We propose an interdisciplinary framework to bridge the different time and space scales of ligand-tumor-host interactions: intravital fluorescence microscopy to quantify probe internalization at the cellular level, a xenograft tumor model for whole body pharmacokinetics, and a computational pharmacokinetic model for integration and interpretation of experimental data. Administration of the probe into mice bearing tumors with high and low MC1R expression demonstrated normalized image intensities that correlated with expression levels (p < 0.05). The biodistribution study showed high kidney uptake as early as 30 min postinjection. The PK computational model predicted the presence of receptors in the kidneys with a lower affinity, but at higher numbers than in the tumors. As the mouse kidney is known to express the MC5R, this hypothesis was confirmed by both coinjection of a ligand with higher MC5R affinity compared to MC1R and by injection of lower probe concentrations (e.g., 1 nmol/kg), both leading to decreased kidney accumulation of the MC1R ligand. In addition, through this interdisciplinary approach we could predict the rates of ligand accumulation and clearance into and from organs and tumors, and the amount of injected ligand required to have maximum specific retention in tumors. These predictions have potential to aid in the translation of a targeted agent from lab to the clinic. In conclusion, the characterized MC1R-specific probe has excellent potential for in vivo detection of melanoma metastases. The process of cell-surface marker validation, targeted imaging probe development, and in vitro, in vivo, and in silico characterization described in this study can be generally applied to preclinical development of targeted agents.

Noninvasive detection of breast cancer lymph node metastasis using carbonic anhydrases IX and XII targeted imaging probes

PURPOSE

To develop targeted molecular imaging probes for the noninvasive detection of breast cancer lymph node metastasis.

EXPERIMENTAL DESIGN

Six cell surface or secreted markers were identified by expression profiling and from the literature as being highly expressed in breast cancer lymph node metastases. Two of these markers were cell surface carbonic anhydrase isozymes (CAIX and/or CAXII) and were validated for protein expression by immunohistochemistry of patient tissue samples on a breast cancer tissue microarray containing 47 normal breast tissue samples, 42 ductal carcinoma in situ, 43 invasive ductal carcinomas without metastasis, 46 invasive ductal carcinomas with metastasis, and 49 lymph node macrometastases of breast carcinoma. Targeted probes were developed by conjugation of CAIX- and CAXII-specific monoclonal antibodies to a near-infrared fluorescent dye.

RESULTS

Together, these two markers were expressed in 100% of the lymph node metastases surveyed. Selectivity of the imaging probes were confirmed by intravenous injection into nude mice-bearing mammary fat pad tumors of marker-expressing cells and nonexpressing cells or by preinjection of unlabeled antibody. Imaging of lymph node metastases showed that peritumorally injected probes detected nodes harboring metastatic tumor cells. As few as 1,000 cells were detected, as determined by implanting, under ultrasound guidance, a range in number of CAIX- and CAXII-expressing cells into the axillary lymph nodes.

CONCLUSION

These imaging probes have potential for noninvasive staging of breast cancer in the clinic and elimination of unneeded surgery, which is costly and associated with morbidities.

Connexin 43 is a potential prognostic biomarker for ewing sarcoma/primitive neuroectodermal tumor

Connexins (Cxs) are building unit proteins of gap junctions (GJs) that are prognostic markers in carcinomas. To investigate the role of Cx in Ewing sarcoma (EWS)/primitive neuroectodermal tumor (PNET), we examined the expression of Cx43 and Cx26 in 36 EWS/PNETs and found (1) cytoplasmic Cx43 reactivity in 28/36 (78%) cases. (2) Cx43 score was significantly correlated with overall survival (P = .025). The average scores for patients alive and dead at 3 years are 46.08 and 96.98 (P = .004) at 5 years are 46.06 and 96.42 (P = .002). (3) Metastasis had a significant effect on the overall survival (P = .003). (4) Cytoplasmic Cx26 reactivity was detected in 2 of 36 (6%) patients who died with metastasis. Our results suggest a possible oncogenic and prognostic role for Cx43 and Cx26 in EWS/PNET. The lack of membranous immunoreactivity suggests that the effect of Cx in EWS/PNET is via a GJ function-independent mechanism.

A mammaglobin-A targeting agent for noninvasive detection of breast cancer metastasis in lymph nodes

Pathologic axillary lymph node (ALN) status is an important prognostic factor for staging breast cancer. Currently, status is determined by histopathology following surgical excision of sentinel lymph node(s), which is an invasive, time consuming, and costly procedure with potential morbidity to the patient. Here, we describe an imaging platform for noninvasive assessment of ALN status, eliminating the need for surgical examination of patients to rule out nodal involvement. A targeted imaging probe (MamAb-680) was developed by conjugation of a mammaglobin-A-specific monoclonal antibody to a near-infrared fluorescent dye. Using DNA and tissue microarray, mammaglobin-A was validated as a cell-surface target that is expressed in ALN-positive patient samples but is not expressed in normal lymph nodes. In vivo selectivity was determined by i.v. injection of MamAb-680 into mice with mammaglobin-A-positive and -negative mammary fat pad (MFP) tumors; and by peritumoral MFP injection of the targeted imaging probe in mice with spontaneous ALN metastases. Fluorescence imaging showed that probe was only retained in positive tumors and metastases. As few as 1,000 cells that endogenously express mammaglobin-A were detected in ALN, indicating high sensitivity of this method. Translation of this approach offers considerable potential as a noninvasive clinical strategy to stage breast cancer.

Thymidylate synthase 1 (TS1) in-situ protein expression predicts the survival of Ewing/PNET

Thymidylate synthase (TS1), RRM1, and ERCC1, which are crucial for DNA synthesis and repair and have shown prognostic and predictive value in carcinomas, were investigated in Ewing/primitive neuroectodermal tumor (PNET). The tissue microarray consisting of 31 archived Ewing/PNET samples was subjected to immunohistochemistry based on immunofluorescence combined with automated quantitative analysis (AQUA) to assess in-situ expression. Automated quantitative analysis score was analyzed with various clinicopathologic data. TS1 was immunoreactive in the nucleus and cytoplasm, while RRM1 and ERCC1 were nuclear. High TS1 expression, not RRM1 and ERCC1, was associated with long overall survival (p value = 0.057). Thus in-situ TS1 protein expression in Ewing/PNET is a prognostic marker.