Diana M. Cardona

Identification of liver cancer-specific aptamers using whole live cells.

Liver cancer is the third most deadly cancers in the world. Unfortunately, there is no effective treatment. One of the major problems is that most cancers are diagnosed in the later stage, when surgical resection is not feasible. Thus, accurate early diagnosis would significantly improve the clinical outcome of liver cancer. Currently, there are no effective molecular probes to recognize biomarkers that are specific for liver cancer. The objective of our current study is to identify liver cancer cell-specific molecular probes that could be used for liver cancer recognition and diagnosis. We applied a newly developed cell-SELEX (Systematic Evolution of Ligands by EXponential enrichment) method for the generation of molecular probes for specific recognition of liver cancer cells. The cell-SELEX uses whole live cells as targets to select aptamers (designed DNA/RNA) for cell recognition. In generating aptamers for liver cancer recognition, two liver cell lines were used: a liver cancer cell line BNL 1ME A.7R.1 (MEAR) and a noncancer cell line, BNL CL.2 (BNL). Both cell lines were originally derived from Balb/cJ mice. Through multiple rounds of selection using BNL as a control, we have identified a panel of aptamers that specifically recognize the cancer cell line MEAR with Kd in the nanomolar range. We have also demonstrated that some of the selective aptamers could specifically bind liver cancer cells in a mouse model. There are two major new results (compared with our reported cell-SELEX methodology) in addition to the generation of aptamers specifically for liver cancer. The first one is that our current study demonstrates that cell-based aptamer selection can select specific aptamers for multiple cell lines, even for two cell lines with minor differences (MEAR cell is derived from BNL by chemical inducement); and the second result is that cell-SELEX can be used for adhesive cells and thus open the door for solid tumor selection and investigation. The newly generated cancer-specific aptamers hold great promise as molecular probes for cancer early diagnosis and basic mechanism studies.

The antigen for Hep Par 1 antibody is the urea cycle enzyme carbamoyl phosphate synthetase 1

Hepatocyte paraffin 1 (Hep Par 1), a murine monoclonal antibody, is widely used in surgical pathology practice to determine the hepatocellular origin of neoplasms. However, identity of the antigen for Hep Par 1 is unknown. The aim of this study was to characterize the Hep Par 1 antigen. To identify the antigen, immunoprecipitation was used to isolate the protein from human liver tissue, and a distinct protein band was detected at approximately 165 kDa. The protein band was also present in small intestinal tissue, but was not present in several other non-liver tissues nor in three human hepatocellular carcinoma cell lines, Huh-7, HepG2, and LH86. The protein was purified and analyzed by mass spectrometry. It was identified as carbamoyl phosphate synthetase 1 (CPS1). CPS1 is a rate-limiting enzyme in urea cycle and is located in mitochondria. We demonstrated that hepatoid tumors (gastric and yolk sac) were immunoreactive with both Hep Par 1 antibody and anti-CPS1 antibody, further confirming the results of mass spectrometric analysis. We found that the three human hepatocellular carcinoma cell lines do not express either CPS1 RNA or protein. We confirmed that the gene was present in these cell lines, suggesting that suppression of CPS1 expression occurs at the transcriptional level. This finding may have relevance to liver carcinogenesis, since poorly differentiated hepatocellular carcinomas exhibit poor to absent immunoreactivity to Hep Par 1. In conclusion, we have identified the antigen for Hep Par 1 antibody as a urea cycle enzyme CPS1. Our results should encourage further investigation of potential role that CPS1 expression plays in liver pathobiology and carcinogenesis.

Heparan sulfate, an endogenous TLR4 agonist, promotes acute GVHD after allogeneic stem cell transplantation

Graft-versus-host disease (GVHD) remains the most common cause of nonrelapse-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although T-cell depletion and intensive immunosuppression are effective in the control of GVHD, they are often associated with higher rates of infection and tumor recurrence. In this study, we showed that heparan sulfate (HS), an extracellular matrix component, can activate Toll-like receptor 4 on dendritic cells in vitro, leading to the enhancement of dendritic cell maturation and alloreactive T-cell responses. We further demonstrated in vivo that serum HS levels were acutely elevated at the onset of clinical GVHD in mice after allo-HSCT. Treatment with the serine protease inhibitor α1-antitrypsin decreased serum levels of HS, leading to a reduction in alloreactive T-cell responses and GVHD severity. Conversely, an HS mimetic that increased serum HS levels accelerated GVHD. In addition, in patients undergoing allo-HSCT for hematologic malignancies, serum HS levels were elevated and correlated with the severity of GVHD. These results identify a critical role for HS in promoting acute GVHD after allo-HSCT, and they suggest that modulation of HS release may have therapeutic potential for the control of clinical GVHD.

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

A first-in-human phase 1 clinical trial of the PEGylated protease-activated fluorescent probe, LUM015, enables tumor imaging at a safe and tolerable dose in humans. Protease probe tested in humans Cancer cells secrete more of the protease cathepsin than healthy cells, partly as a way to enzymatically remodel their surroundings for tumor growth and metastasis. Whitley et al. developed an imaging probe that could be activated in the presence of these cathepsins, thus allowing surgeons to distinguish tumor margins intraoperatively. Their probe, called LUM015, was able to signal the presence of cancer in vivo in a mouse sarcoma model, and in a so-called “co-clinical trial” in 15 patients, it was safe and cleaved as expected in different types of tumor tissues. With favorable biodistribution and pharmacokinetics also demonstrated, protease-activated probes are now poised for further adaptation to tumor resections, signaling the presence of residual cancer. Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

MicroRNA-182 drives metastasis of primary sarcomas by targeting multiple genes

Metastasis causes most cancer deaths, but is incompletely understood. MicroRNAs can regulate metastasis, but it is not known whether a single miRNA can regulate metastasis in primary cancer models in vivo. We compared the expression of miRNAs in metastatic and nonmetastatic primary mouse sarcomas and found that microRNA-182 (miR-182) was markedly overexpressed in some tumors that metastasized to the lungs. By utilizing genetically engineered mice with either deletion of or overexpression of miR-182 in primary sarcomas, we discovered that deletion of miR-182 substantially decreased, while overexpression of miR-182 considerably increased, the rate of lung metastasis after amputation of the tumor-bearing limb. Additionally, deletion of miR-182 decreased circulating tumor cells (CTCs), while overexpression of miR-182 increased CTCs, suggesting that miR-182 regulates intravasation of cancer cells into the circulation. We identified 4 miR-182 targets that inhibit either the migration of tumor cells or the degradation of the extracellular matrix. Notably, restoration of any of these targets in isolation did not alter the metastatic potential of sarcoma cells injected orthotopically, but the simultaneous restoration of all 4 targets together substantially decreased the number of metastases. These results demonstrate that a single miRNA can regulate metastasis of primary tumors in vivo by coordinated regulation of multiple genes.

Preoperative or postoperative radiotherapy versus surgery alone for retroperitoneal sarcoma: a case-control, propensity score-matched analysis of a nationwide clinical oncology database

BACKGROUND Recruitment into clinical trials for retroperitoneal sarcoma has been challenging, resulting in termination of the only randomised multicentre trial in the USA investigating perioperative radiotherapy. Nonetheless, use of radiotherapy for retroperitoneal sarcoma has increased over the past decade, substantiated primarily by its established role in extremity sarcoma. In this study, we used a nationwide clinical oncology database to separately compare overall survival for patients with retroperitoneal sarcoma who had surgery and preoperative radiotherapy or surgery and postoperative radiotherapy versus surgery alone. METHODS We did two case-control, propensity score-matched analyses of the National Cancer Data Base, which included adult patients with retroperitoneal sarcoma who were diagnosed from 2003 to 2011. Patients were included if they had localised, primary retroperitoneal sarcoma. Patients were classified into three groups based on use of radiotherapy: preoperative radiotherapy, postoperative radiotherapy, and no radiotherapy (surgery alone). Patients were excluded if they received both preoperative radiotherapy and postoperative radiotherapy, or if they received intraoperative radiotherapy. Parallel propensity score-matched datasets were created for patients who received preoperative radiotherapy versus those who received no radiotherapy and for patients who received postoperative therapy versus those who received no radiotherapy. Propensity scores were calculated with logistic regression, with multiple imputation and backwards elimination, with a significance level to stay of 0·05. Matching was done with a nearest-neighbour algorithm and matched 1:2 for the preoperative radiotherapy dataset and 1:1 for the postoperative radiotherapy dataset. The primary objective of interest was overall survival for patients who received preoperative radiotherapy or postoperative radiotherapy compared with those who received no radiotherapy within the propensity score-matched datasets. FINDINGS 9068 patients were included in this analysis: 563 in the preoperative radiotherapy group, 2215 in the postoperative radiotherapy group, and 6290 in the no radiotherapy group. Matching resulted in two comparison groups (preoperative radiotherapy vs no radiotherapy, and postoperative radiotherapy vs no radiotherapy) with negligible differences in all demographic, clinicopathological, and treatment-level variables. In the matched case-control analysis for preoperative radiotherapy median follow-up time was 42 months (IQR 27-70) for the preoperative radiotherapy group versus 43 months (25-64) for the no radiotherapy group; median overall survival was 110 months (95% CI 75-not estimable) versus 66 months (61-76), respectively. In the matched case-control analysis for postoperative radiotherapy median follow-up time was 54 months (IQR 32-79) for patients in the postoperative radiotherapy group and 47 months (26-72) for patients in the no radiotherapy group; median overall survival was 89 months (95% CI 79-100) versus 64 months (59-69), respectively. Both preoperative radiotherapy (HR 0·70, 95% CI 0·59-0·82; p<0·0001) and postoperative radiotherapy (HR 0·78, 0·71-0·85; p<0·0001) were significantly associated with improved overall survival compared with surgery alone. INTERPRETATION To the best of our knowledge, this is the largest study to date of the effect of radiotherapy on overall survival in patients with retroperitoneal sarcoma. Radiotherapy was associated with improved overall survival compared with surgery alone when delivered as either preoperative radiotherapy or postoperative radiotherapy. Together with the results from the ongoing randomised EORTC trial (62092-22092; NCT01344018) investigating preoperative radiotherapy for retroperitoneal sarcoma pending, these data might provide additional support for the increasing use of radiotherapy for patients with retroperitoneal sarcoma undergoing surgical resection. FUNDING Department of Surgery, Duke University School of Medicine.

Evaluation of repeat Clostridium difficile enzyme immunoassay testing.

ABSTRACT Clostridium difficile is the leading cause of antibiotic-associated diarrhea and pseudomembranous colitis, which have significant morbidity and mortality. Accurate and timely diagnosis is critical. Repeat enzyme immunoassay testing for C. difficile toxin has been recommended because of <100% sensitivity. All C. difficile tests between 1 January 2006 and 31 December 2006 were retrospectively analyzed for results and testing patterns. The Wampole C. difficile Tox A/B II enzyme immunoassay kit was used. There were a total of 8,256 tests from 3,112 patients; 49% of tests were repeated. Of the 3,749 initially negative patient tests, 96 were positive upon repeat testing within 10 days of the first test. Of repeat tests, 0.9% repeated on day 0 (same day as the first test), 1.8% on day 1, 3.8% on day 2, 2.6% on day 3, 5.4% on days 4 to 6, and 10.6% on days 7 to 10 were positive. Thirty-eight patients had a positive test within 48 h of an initial negative test, and based on chart review, 18 patients were treated empirically while 16 were treated following the new result. None had evidence of medical complications. Of initially positive patients, 91% were positive upon repeat testing on day 0, 75% on day 1, and 58% on day 2, to a low of 14% on days 7 to 10. Depending on the clinical setting, these data support not repeating C. difficile tests within 2 days of a negative result and limiting repeat testing to ≥1 week of a positive result.

Costaining for keratins 8/18 plus ubiquitin improves detection of hepatocyte injury in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is a global health dilemma. The gold standard for diagnosis is liver biopsy. Ballooned hepatocytes are histologic manifestations of hepatocellular injury and are characteristic of steatohepatitis, the more severe form of nonalcoholic fatty liver disease. Definitive histologic identification of ballooned hepatocytes on routine stains, however, can be difficult. Immunohistochemical evidence for loss of the normal hepatocytic keratin 8/18 can serve as an objective marker of ballooned hepatocytes. We sought to explore the utility of a keratin 8/18 plus ubiquitin double immunohistochemical stain for the histologic evaluation of adult nonalcoholic fatty liver disease. Double immunohistochemical staining for keratin 8/18 and ubiquitin was analyzed using 40 adult human nonalcoholic fatty liver disease core liver biopsies. Ballooned hepatocytes lack keratin 8/18 staining as previously shown by others, but normal-size hepatocytes with keratin loss are approximately 5 times greater in number than keratin-negative ballooned hepatocytes. Keratin-negative ballooned hepatocytes, normal-size hepatocytes with keratin loss, and ubiquitin deposits show a zonal distribution, are positively associated with each other, and are frequently found adjacent to or intermixed with fibrous matrix. All 3 lesions correlate with fibrosis stage and the hematoxylin and eosin diagnosis of steatohepatitis (all P < .05). Compared with hematoxylin and eosin staining, immunohistochemical staining improves the receiver operating characteristics curve for advanced fibrosis (0.77 versus 0.83, 0.89, and 0.89 for keratin-negative ballooned hepatocytes, normal-size hepatocytes with keratin loss, and ubiquitin, respectively) because immunohistochemistry is more sensitive and specific for fibrogenic hepatocellular injury than hematoxylin and eosin staining. Keratin 8/18 plus ubiquitin double immunohistochemical stain improves detection of hepatocyte injury in nonalcoholic fatty liver disease. Thus, it may help differentiate nonalcoholic steatohepatitis from nonalcoholic fatty liver.

Hepatocellular carcinoma arising from ectopic liver tissue in the pancreas

Liver tissue ectopia is a well-documented phenomenon. Rarely, hepatocellular carcinoma arises from the ectopic liver tissue. In this paper, we report a case of a primary, well-differentiated hepatocellular carcinoma arising from ectopic liver tissue in the pancreas. The patient is a 58-year-old Hispanic man with no history of underlying liver diseases or chronic pancreatic diseases. Patient presented with a several days history of abdominal pain with radiation to his right upper quadrant. Imaging study revealed a 3.7 × 3.3-cm mass in the distal pancreas. No other lesions were identified. Preoperative fine needle aspiration revealed blood and atypical hepatocytes. The patient underwent distal pancreatectomy and splenectomy for suspected neuroendocrine tumor. Gross examination revealed a well-circumscribed 3.3-cm, beige-tan, pseudolobulated tumor with focal areas of hyperpigmentation. A microscopic examination revealed hepatoid cells arranged in a trabecular pattern with focal bile pigment. Immunohistochemistry study showed that the tumor cells were reactive with hepatocyte antigen (Hep par 1), alpha-1 antitrypsin, but negative for synaptophysin and chromogranin. Immunostain for polyclonal carcinoembryonic antigen showed a typical bile canalicular pattern. These results support that this tumor in the pancreas is hepatocellular carcinoma, most likely arising from ectopic liver tissue within the pancreas.

Targeting eNOS in Pancreatic Cancer

Mortality from pancreatic ductal adenocarcinoma cancer (PDAC) is among the highest of any cancer and frontline therapy has changed little in years. Activation of endothelial nitric oxide synthase (eNOS, NOS3, or NOS III) has been implicated recently in the pathogenesis of PDACs. In this study, we used genetically engineered mouse and human xenograft models to evaluate the consequences of targeting eNOS in PDACs. Genetic deficiency in eNOS limited the development of preinvasive pancreatic lesions and trended toward an extended lifespan in mice with advanced pancreatic cancer. These effects were also observed upon oral administration of the clinically evaluated NOS small molecule inhibitor N(G)-nitro-L-arginine methyl ester (l-NAME). Similarly, other transgenic models of oncogenic KRas-driven tumors responded to l-NAME treatment. Finally, these results were recapitulated in xenograft models of human pancreatic cancer, in which l-NAME was found to broadly inhibit tumorigenic growth. Taken together, our findings offer preclinical proof-of-principle to repurpose l-NAME for clinical investigations in treatment of PDACs and possibly other KRas-driven human cancers.