Sejal S. Shah

Identification of a Novel Peptide That Interferes With the Chemical Regulation of Connexin43

The carboxyl-terminal domain of connexin43 (Cx43CT) is involved in various intra- and intermolecular interactions that regulate gap junctions. Here, we used phage display to identify novel peptidic sequences that bind Cx43CT and modify Cx43 regulation. We found that Cx43CT binds preferentially to peptides containing a sequence RXP, where X represents any amino acid and R and P correspond to the amino acids arginine and proline, respectively. A biased “RXP library” led to the identification of a peptide (dubbed “RXP-E”) that bound Cx43CT with high affinity. Nuclear magnetic resonance data showed RXP-E–induced shifts in the resonance peaks of residues 343 to 346 and 376 to 379 of Cx43CT. Patch-clamp studies revealed that RXP-E partially prevented octanol-induced and acidification-induced uncoupling in Cx43-expressing cells. Moreover, RXP-E increased mean open time of Cx43 channels. The full effect of RXP-E was dependent on the integrity of the CT domain. These data suggest that RXP-based peptides could serve as tools to help determine the role of Cx43 as a regulator of function in conditions such as ischemia-induced arrhythmias.

Neuroprotective effects of erythropoietin on acute metabolic and pathological changes in experimentally induced neurotrauma

OBJECT Head trauma is a dynamic process characterized by a cascade of metabolic and molecular events. Erythropoietin (EPO) has been shown to have neuroprotective effects in animal models of traumatic brain injury (TBI). Acute in vivo mechanisms and pathological changes associated with EPO following TBI are unknown. In this study the authors compare acute metabolic and pathological changes following TBI with and without systemically administered EPO. METHODS Right frontal lobe microdialysis cannulae and right parietal lobe percussion hubs were inserted into 16 Sprague-Dawley rats. After a 4- to 5-day recovery, TBI was induced via a DragonFly fluid-percussion device at 2.5-2.8 atm. Rats were randomized into 2 groups, which received 5000 U/kg EPO or normal saline intraperitoneally 30 minutes after TBI. Microdialysis samples for glucose, lactate, pyruvate, and glutamate were obtained every 25 minutes for 10 hours. Rats were killed, their brains processed for light microscopy, and sections stained with H & E. RESULTS Erythropoietin administered 30 minutes after TBI directly affects acute brain metabolism. Brains treated with EPO maintain higher levels of glucose 4-10 hours after TBI (p<0.01), lower levels of lactate 6-10 hours after TBI (p<0.01), and lower levels of pyruvate 7.5-10 hours after TBI (p<0.01) compared with saline-treated controls. Erythropoietin maintains aerobic metabolism after TBI. Systemic EPO administration reduces acute TBI-induced lesion volume (p<0.05). CONCLUSIONS Following TBI, neuron use initially increases, with subsequent depletion of extracellular glucose, resulting in increased levels of extracellular lactate and pyruvate. This energy requirement can result in cell death due to increased metabolic demands. These data suggest that the neuroprotective effect of EPO may be partially due to improved energy metabolism in the acute phase in this rat model of TBI.

Mirk/Dyrk1b Mediates Cell Survival in Rhabdomyosarcomas

Rhabdomyosarcoma is the most common sarcoma in children and is difficult to treat if the primary tumor is nonresectable or if the disease presents with metastases. The function of the serine/threonine kinase Mirk was investigated in this cancer. Mirk has both growth arrest and survival functions in terminally differentiating skeletal myoblasts. Maintenance of Mirk growth arrest properties would cause down-regulation of Mirk in transformed myoblasts. Alternatively, Mirk expression would be retained if rhabdomyosarcoma cells used Mirk survival capability. Mirk expression was significant in 12 of 16 clinical cases of rhabdomyosarcoma. Mirk was detected in each rhabdomyosarcoma cell line examined. Mirk was a functional kinase in each of three rhabdomyosarcoma cell lines, where it proved to be more active than in C2C12 skeletal myoblasts. Mirk mediated survival of the majority of clonogenic rhabdomyosarcoma cells. Knockdown of Mirk by RNA interference reduced the fraction of RD and of Rh30 rhabdomyosarcoma cells capable of colony formation 3- to 4-fold in multiple experiments. Depletion of Mirk induced cell death by apoptosis, as shown by increased numbers of terminal deoxynucleotidyl transferase-mediated nick-end labeling-positive cells and by increased binding of Annexin V. Mirk is a stress-activated kinase that mediates expression of contractile proteins in differentiating myoblasts, but Mirk is not essential for muscle formation in the embryo. It is likely that Mirk also facilitates survival of satellite cell-derived rhabdomyoblasts in regenerating skeletal muscle and aids their differentiation. This survival function is maintained in rhabdomyosarcoma, where Mirk may be a novel therapeutic target.

Effect of high copy number of HER2 associated with polysomy 17 on HER2 protein expression in invasive breast carcinoma

HER2 gene amplification by fluorescence in situ hybridization and protein expression by immunohistochemistry (IHC) have been used for prognosis and guiding treatment of invasive ductal carcinoma of the breast with trastuzumab. Accurate evaluation of HER2 status is important in the management of patients with candidacy for the HER2-targeting therapy. Despite previous studies, effects of polysomy of chromosome 17, at which HER2 is located, on HER2 protein expression remains controversial. In this study, we calculated the average copy numbers of HER2 and chromosome 17 (CEP17) per nucleus in 109 cases of invasive breast carcinoma and analyzed their correlations with the HER2/CEP17 ratio and protein expression. As expected, there were close correlations between HER2 protein expression and the HER2/CEP17 ratio (CC: 0.49, P<0.001), along with the HER2 copy number per nucleus (CC: 0.48, P<0.001) and between the CEP17 copy number per nucleus and the HER2 copy number per nucleus (CC: 0.45, P<0.001). Correlation between the CEP17 copy number per nucleus and the HER2/CEP17 ratio was not significant (CC: 0.2, P>0.05). There was a weak, but statistically insignificant, correlation between the CEP17 copy number per nucleus and HER2 protein expression by IHC (CC: 0.26, P>0.05). The cases were then grouped on the basis of the amplification of the HER2 gene by fluorescence in situ hybridization. In the cases that showed no amplification, there was a significantly higher CEP17 copy number per nucleus in cases with strong HER2 protein expression (2.99) when compared with cases with weak (2.39) or absent (1.86) expression. In conclusion, a high HER2 gene copy number-associated polysomy 17 is a significant contributing factor in HER2 protein overexpression in unamplified invasive breast carcinomas. Cases without HER2 amplification, but carrying polysomy 17, should be further evaluated for HER2 protein overexpression by IHC. Those with polysomy 17-associated HER2 protein overexpression, like any other IHC+ ones, should be eligible candidates for trastuzumab therapy.

Adenocarcinoma in situ arising in vulvar papillary hidradenoma: report of 2 cases.

Adenocarcinoma in situ rarely occurs in vulvar papillary hidradenoma. We encountered 2 cases of adenocarcinoma in situ arising in a papillary hidradenoma of the vulva. Both patients were asymptomatic women, aged 83 and 92 years, who presented with nodules (1.0 and 2.0 cm) on the vulva. Macroscopically, the lesions seemed tan-pink, fleshy, and well circumscribed. One tumor ulcerated the overlying epidermis. On microscopic examination, the tumors showed focal features of benign hidradenoma at the periphery with transitions into areas of increasing cytologic atypia that fulfilled criteria for adenocarcinoma in situ similar to that seen in the breast. One tumor showed a predominant cribriform pattern with moderate atypia and many mitoses; the other showed a mixture of cribriform and micropapillary patterns, mild atypia, and fewer mitotic figures. There was no evidence of destructive invasion or desmoplasia in either tumor. Both lesions show areas strongly immunoreactive for mammaglobin and gross cystic disease fluid protein 15 as well as estrogen and progesterone receptor protein in 1 case. There was no evidence of benign ectopic breast tissue within or adjacent to the neoplasms. Both patients underwent local excision with no evidence of tumor recurrence at 15 and 32 months of follow-up. The fact that these tumors displayed morphologic and immunohistochemical features that resembled ductal carcinoma in situ of the breast demonstrates the close homology between papillary hidradenoma and breast epithelium. In the absence of invasion, our experience suggests that these tumors can be cured by local excision.

Endometrial eosinophilic syncytial change related to breakdown: immunohistochemical evidence suggests a regressive process.

Eosinophilic syncytial change (ESC), also known as papillary syncytial change, occurs in association with endometrial breakdown and bleeding, especially in nonphysiological conditions. When prominent, this morphological alteration yields a pattern of eosinophilic epithelial cells, often in pseudopapillary arrangements that can mimic cellular changes seen in metaplastic and atypical endometrium. To determine if ESC represents a proliferative, regenerative process or a degenerative, retrogressive alteration, we assessed whether the cells of ESC were actively growing. Our methodology involved a retrospective immunohistochemical study on endometrial biopsies with proliferation markers Ki-67 (MIB-1 antibody) and phosphohistone H3 Ser 28 (pHH3) in 15 cases of multifocal ESC associated with benign endometrium, 5 cases of atypical hyperplasia, and 7 cases of endometrial carcinoma. The Ki-67 proliferative index and the pHH3 mitotic index were calculated per 100 cells for each case. On immunohistochemical analysis, the Ki-67 labeling index was 1.3% for cases of ESC (mean age, 53 yr), 15.8% in atypical hyperplasia (mean age, 51.6 yr), and 42.6% in endometrial carcinoma (mean age, 68.1 yr). In the endometrial cancers, the Ki-67 proliferative index was 10.6% for FIGO grade 1 tumors (n=3), 27.6% for grade 2 tumor (n=1), and 79.6% for serous carcinoma (n=3). The mitotic index calculated from pHH3 immunostaining was zero in all cases of ESC, whereas it was 2.3% in atypical hyperplasia and 4.8% in endometrial carcinomas (2.4% for grade 1, 3% for grade 2, and 7.8% for serous). Our results indicate that ESC is a regressive change. Furthermore, when there is a question of whether eosinophilic endometrial epithelium represents this change, a combination of Ki-67 and pHH3 immunostains can be helpful in distinguishing this entity from more significant processes including carcinoma.

FNA of misclassified primary malignant neoplasms of the thyroid: Impact on clinical management

Background: Fine needle aspiration (FNA) cytology is a popular, reliable and cost effective technique for the diagnosis of thyroid lesions. The aim of our study was to review cases of misclassified primary malignant neoplasms of the thyroid by FNA, and assess the causes of cytologic misdiagnosis and their impact on clinical management. Methods: Clinical data, FNA smears and follow-up surgical specimens of cases diagnosed with primary thyroid carcinoma were reviewed. Results: Of the 365 cases with a malignant diagnosis by FNA over a period of 11 years, nine (2.4 %) were identified with discrepant histologic diagnosis with regard to the type of primary thyroid malignancy. In addition, four cases were added from the consultation files of the Massachusetts General Hospital. Areas of difficulty contributing to misclassification included overlapping cytologic features (n = 6), rarity of tumors (n = 3), and sampling limitations (n = 4). Of the 13 cases, 12 underwent total or near total thyroidectomy and one patient had concurrent surgical biopsy. Measurement of serum calcitonin levels in one case, with an initial cytologic diagnosis of medullary carcinoma, prevented unnecessary lymph node dissection. Misclassification of medullary carcinoma as papillary carcinoma precluded lymph node dissection in one case. Further management decisions were based on the final histologic diagnosis and did not require additional surgery. Two cases of undifferentiated (anaplastic) thyroid carcinoma were misdiagnosed as papillary thyroid carcinoma. Both patients received total thyroidectomies, which may not otherwise have been performed. Conclusions: A small subset of primary malignant neoplasms of the thyroid may be misclassified with regard to the type of malignancy on FNA. The majority of primary malignant neoplasms diagnosed on FNA require thyroidectomy. However, initial cytologic misclassification of medullary carcinoma or undifferentiated carcinoma as other malignant neoplasms or vice versa may have an impact on clinical management.

Immunostains Used to Subtype Hepatic Adenomas Do Not Distinguish Hepatic Adenomas From Hepatocellular Carcinomas.

Immunostains are used to subtype hepatic adenomas to stratify for the risk of malignant transformation. The most common panel of immunostains used for this purpose includes liver fatty acid–binding protein (LFABP), serum amyloid A (SAA) protein, C-reactive protein (CRP), and glutamine synthetase (GS). Importantly, some pathologists use these stains in an attempt to distinguish hepatocellular carcinomas (HCC) from hepatic adenomas. However, there are limited data on the performance of these stains in HCCs. To investigate the staining characteristics of HCCs, we studied 159 HCCs (92 well-differentiated, 67 moderately differentiated, and 7 poorly differentiated) and 7 fibrolamellar carcinomas for the expression of LFABP, SAA, CRP, and GS. All of the stains were positive in at least a subset of HCCs: SAA was positive in 27 of 159 (17%), CRP in 86 of 159 (54%), and GS in 23 of 47 (49%) cases; LFABP showed loss of staining in 36 of 159 (23%) cases. Fibrolamellar carcinomas were consistently CRP positive (7 of 7 cases) and frequently showed loss of LFABP (4 of 7 cases). There was no association between expression of SAA, CRP, and GS as well as loss of LFABP expression and other clinicopathologic features. HCCs with loss of LFABP were more frequently associated with negative GS expression (11 of 14 cases, P=0.02). These data show that immunostains used to subtype hepatic adenomas are not useful for distinguishing HCCs from hepatic adenomas and should be used only after a diagnosis of hepatic adenoma has been made using other criteria.

Hepatocyte Antigen Expression in Barrett Esophagus and Associated Neoplasia.

Hepatocyte antigen or hepatocyte paraffin 1 (Hep Par 1) is widely used as a diagnostic immunomarker for hepatocellular carcinoma. It has also been identified as a rate-limiting enzyme of the urea cycle, carbamoyl phosphate synthetase 1. Hep Par 1 has been detected in non-neoplastic small intestinal epithelium, but its expression in Barrett esophagus and its related neoplasia has not been well investigated. We immunohistochemically evaluated expression of Hep Par 1 on 75 cases of Barrett esophagus (25 cases without dysplasia, 16 cases with low-grade dysplasia, 25 cases with high-grade dysplasia, and 9 cases with intramucosal adenocarcinoma) on endoscopic biopsies and endoscopic mucosal resections. All 25 cases without dysplasia (100%) showed granular cytoplasmic Hep Par 1 staining (24 diffuse and 1 focal). Of the 16 cases with low-grade dysplasia, 12 (75%) were positive (5 diffuse and 7 focal), whereas 4 (25%) were negative (P=0.018). Of the 25 cases with high-grade dysplasia, 9 (36%) showed focal positivity, whereas 16 (64%) were negative (P=0.0001). Similarly of the 9 cases of intramucosal adenocarcinomas 3 (33%) were focally positive, whereas 6 (67%) were negative (P=0.0001). Hep Par 1 is diffusely expressed in non-neoplastic Barrett esophagus while it is frequently lost in related dysplasia and adenocarcinoma, suggesting decreased level of HepPar1 may represent an early event in Barrett-related tumor genesis. This warrants additional investigation to look for the possible role of carbamoyl phosphate synthetase 1 in the pathogenesis of Barrett-related neoplasia.