Cytokeratin 18 in plasma of patients with gastrointestinal adenocarcinoma as a biomarker of tumour response. Br J Cancer. 2009;101:410-417. [PMID: 19603019 PMCID: PMC2720228 DOI: 10.1038/sj.bjc.6605175]

Establishing reference ranges for circulating biomarkers of drug-induced liver injury in healthy human volunteers

AIMS

The potential of mechanistic biomarkers to improve prediction of drug-induced liver injury (DILI) and hepatic regeneration is widely acknowledged. We sought to determine reference intervals for new biomarkers of DILI and regeneration, as well as to characterize their natural variability and impact of diurnal variation.

METHODS

Serum samples from 227 healthy volunteers were recruited as part of a cross-sectional study; of these, 25 subjects had weekly serial sampling over 3 weeks, while 23 had intensive blood sampling over a 24h period. Alanine aminotransferase (ALT), MicroRNA-122 (miR-122), High Mobility Group Box-1 (HMGB1), total Keratin-18 (K18), caspase-cleaved Keratin-18 (ccK18), Glutamate Dehydrogenase (GLDH) and Macrophage Colony-Stimulating Factor-1 (CSF-1) were assayed.

RESULTS

Reference intervals were established for each biomarker based on the 97.5% quantile (90% CI) following the assessment of fixed effects in univariate and multivariable models. Intra-individual variability was found to be non-significant, and there was no significant impact of diurnal variation.

CONCLUSION

Reference intervals for novel DILI biomarkers have been described. An upper limit of a reference range might represent the most appropriate mechanism to utilize these data. These data can now be used to interpret data from exploratory clinical DILI studies and to assist their further qualification as required by regulatory authorities.

Cytokeratin 18 in nonalcoholic fatty liver disease: value and application

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a common metabolism-related disease worldwide. Although studies have shown that some medications may be effective for treating NAFLD, they do not satisfy the medical requirements, and lifestyle changes are the most basic strategy. Thus, early detection of NAFLD and timely lifestyle interventions are highly important.

AREAS COVERED

The traditional diagnostic methods for NAFLD are limited by accuracy, cost, and security issues. Cytokeratin 18 (CK18), which is a marker of apoptosis and overall cell death, is an excellent biomarker for NAFLD. Liver fat accumulation in NAFLD triggers the activation of caspases, which increases the CK18 cleavage and its release into the blood. CK18 can help diagnose different stages of NAFLD, especially the nonalcoholic steatohepatitis (NASH) stage. In evaluating the efficacy of the NAFLD treatment and predicting the risk of NAFLD-related diseases, CK18 plays a significant role.

EXPERT OPINION

CK18 can non-invasively monitor the pathological conditions of NAFLD patients and provide new hope for the early diagnosis of NAFLD. Adding CK18 to the NAFLD diagnostic criteria that are widely used in clinical settings may be efficient for the detection of NAFLD and early effective intervention.

Preliminary study on the diagnostic value of LEAP-2 and CK18 in biopsy-proven MAFLD

Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) has become the leading cause of chronic liver disease. Liver biopsy, as the diagnostic gold standard, is invasive and has sampling bias, making it particularly important to search for sensitive and specific biomarkers for diagnosis. Cytokeratin 18 (CK18) M30 and M65 are products of liver cell apoptosis and necrosis, respectively, and liver-expressed antimicrobial peptide 2 (LEAP-2) is a related indicator of glucose and lipid metabolism. Correlation studies have found that all three indicators positively correlate with the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Through comparison of diagnostic values, it was found that CK18 M65 can better distinguish between healthy individuals and MAFLD; LEAP-2 can effectively distinguish MAFLD from other liver diseases, especially ALD.

Hepatocyte-derived biomarkers predict liver-related events at 2 years in Child-Pugh class A alcohol-related cirrhosis

BACKGROUND & AIMS

In patients with compensated alcohol-related cirrhosis, reliable prognostic biomarkers are lacking. Keratin-18 and hepatocyte-derived large extracellular vesicle (lEV) concentrations reflect disease activity, but their ability to predict liver-related events is unknown.

METHODS

We measured plasma keratin-18 and hepatocyte lEV concentrations in 500 patients with Child-Pugh class A alcohol-related cirrhosis. The ability of these hepatocyte-derived biomarkers, alone or combined with model for end-stage liver disease (MELD) and FibroTest scores, to predict liver-related events at 2 years was analyzed, taking into account the alcohol consumption at inclusion and during follow-up.

RESULTS

Keratin-18 and hepatocyte lEV concentrations increased with alcohol consumption. In patients without active alcohol consumption at enrollment (n = 419), keratin-18 concentration predicted liver-related events at 2 years, independently of FibroTest and MELD. Patients with both keratin-18 concentrations >285 U/L and FibroTest >0.74 had a 24% cumulative incidence of liver-related events at 2 years, vs. 5% to 14% in other groups of patients. Similar results were obtained when combining keratin-18 concentrations >285 U/L with MELD >10. In patients with active alcohol consumption at enrollment (n = 81), hepatocyte lEVs predicted liver-related events at 2 years, independently of FibroTest and MELD. Patients with both hepatocyte lEV concentrations >50 U/L and FibroTest >0.74 had a 62% cumulative incidence of liver-related events at 2 years, vs. 8% to 13% in other groups of patients. Combining hepatocyte lEV concentrations >50 U/L with MELD >10 had a lower discriminative ability. Similar results were obtained when using decompensation of cirrhosis, defined according to Baveno VII criteria, as an endpoint.

CONCLUSION

In patients with Child-Pugh class A alcohol-related cirrhosis, combining hepatocyte-derived biomarkers with FibroTest or MELD scores identifies patients at high risk of liver-related events, and could be used for risk stratification and patient selection in clinical trials.

IMPACT AND IMPLICATIONS

In patients with compensated alcohol-related cirrhosis, reliable predictors of outcome are lacking. In patients with Child-Pugh class A alcohol-related cirrhosis, combining hepatocyte-derived biomarkers (keratin-18 and hepatocyte-large extracellular vesicles) with FibroTest or MELD scores identifies those at high risk of liver-related events at 2 years. The identified patients at high risk of liver-related events are the target-of-choice population for intensive surveillance (e.g., referral to tertiary care centers; intensive control of risk factors) and inclusion in clinical trials.

Therapeutic Drug Monitoring as a Tool for Therapy Optimization

The use of pharmacotherapy for improving healthcare in society is increasing. A vast majority of patients have either received subtherapeutic treatment (which could result from low pharmacokinetic) or experienced adverse effects due to the toxic levels of the drug. The medicines used to treat chronic conditions, such as epilepsy; cardiovascular diseases; and oncological, neurological, and psychiatric disorders, require routine monitoring. New targeted therapies suggest an individualized treatment that can slowly move practitioners away from the concept of a one-size-fits-all-fixed-dosing approach. Therapeutic drug use can be monitored based on pharmacokinetic, pharmacodynamic, and pharmacometric methods. Based on the experiences of therapeutic drug monitoring of various agents across the globe, we can look ahead to the possible developments of therapeutic drug monitoring in India.

Hsa-miR-186-3p suppresses colon cancer progression by inhibiting KRT18/MAPK signaling pathway

This study aimed to determine the effect of miR-186-3p and KRT18 interaction on the biological behavior of colon cancer cells. A biotin-microRNA pull-down assay was performed to identify potential miRNAs. qRT-PCR was used to verify the KRT18 and miR-186-3p levels. In addition, Western blotting was used to detect the KRT18 protein levels. The functional connection between KRT18 and miR-186-3p was confirmed using a dual luciferase reporter assay. BrdU incorporation, MTT assay, and flow cytometry were performed to verify the biological function coupled with in vivo assays. A significant decrease in miR-186-3p expression was observed in colon carcinoma tissues and cells. Functionally, overexpression of miR-186-3p displayed an obvious suppressive action on cell proliferation and viability, and a stimulatory action on the apoptotic ability of SW620 and SW480 cells. Conversely, reduced miR-186-3p had a marked stimulatory effect on proliferation and viability, and a suppressive apoptotic effect. Inhibition of tumorigenesis was observed in mice treated with the miR-186-3p agomir. Furthermore, we identified that miR-186-3p regulated KRT18 levels in colon carcinoma, where silenced KRT18 suppressed proliferation and viability and promoted apoptosis. However, the addition of a miR-186-3p inhibitor weakened the effects of si-KRT18. Additionally, the activation of MAPK signaling pathway upon miR-186-3p silencing was antagonized by the combined transfection of si-KRT18 and miR-186-3p inhibitor. miR-186-3p suppresses proliferation and viability, but facilitates apoptosis in colon cancer cells by targeting KRT18 and negatively regulating the MAPK signaling pathway, indicating that the miR-186-3p/KRT18 axis may be a promising therapeutic target for colon carcinoma.Abbreviations: KRT18: keratin 18; NC: negative control; si‑: small interfering RNA; inhibitor: miR-186-3p inhibitor; OD: optical density; PI: propidium iodide; FITC: fluorescein isothiocyanate; 3'UTR: 3'untranslated region; WT: wild-type; MUT: mutant-type; miR: microRNA.

Effect of oxaliplatin plus 5-fluorouracil or capecitabine on circulating and imaging biomarkers in patients with metastatic colorectal cancer: a prospective biomarker study

BACKGROUND

Patients with metastatic colorectal cancer are treated with cytotoxic chemotherapy supplemented by molecularly targeted therapies. There is a critical need to define biomarkers that can optimise the use of these therapies to maximise efficacy and avoid unnecessary toxicity. However, it is important to first define the changes in potential biomarkers following cytotoxic chemotherapy alone. This study reports the impact of standard cytotoxic chemotherapy across a range of circulating and imaging biomarkers.

METHODS

A single-centre, prospective, biomarker-driven study. Eligible patients included those diagnosed with colorectal cancer with liver metastases that were planned to receive first line oxaliplatin plus 5-fluorouracil or capecitabine. Patients underwent paired blood sampling and magnetic resonance imaging (MRI), and biomarkers were associated with progression-free survival (PFS) and overall survival (OS).

RESULTS

Twenty patients were recruited to the study. Data showed that chemotherapy significantly reduced the number of circulating tumour cells as well as the circulating concentrations of Ang1, Ang2, VEGF-A, VEGF-C and VEGF-D from pre-treatment to cycle 2 day 2. The changes in circulating concentrations were not associated with PFS or OS. On average, the MRI perfusion/permeability parameter, Ktrans, increased in response to cytotoxic chemotherapy from pre-treatment to cycle 2 day 2 and this increase was associated with worse OS (HR 1.099, 95%CI 1.01-1.20, p = 0.025).

CONCLUSIONS

In patients diagnosed with colorectal cancer with liver metastases, treatment with standard chemotherapy changes cell- and protein-based biomarkers, although these changes are not associated with survival outcomes. In contrast, the imaging biomarker, Ktrans, offers promise to direct molecularly targeted therapies such as anti-angiogenic agents.

Systemic inflammation is associated with circulating cell death released keratin 18 fragments in colorectal cancer

Systemic inflammation is a stage-independent marker of poor prognosis in colorectal cancer (CRC), activated in a complex, multifactorial process. It has been proposed that one of the main factors driving systemic inflammation may be tumor necrosis. Keratin 18 (KRT18) fragments are released from dead cells and their serum levels are markers for apoptotic and necrotic cell death. In CRC, high KRT18 levels associate with advanced disease, but their relationship with tumor necrosis and systemic inflammation is unknown. In this study, serum total soluble KRT18 (tKRT18) and apoptosis-related, caspase-cleaved fragment (aKRT18) levels were measured preoperatively from 328 CRC patients, and their difference was calculated to assess necrosis related KRT18 (nKRT18) levels. The relationships of these markers with tumor necrosis, clinicopathologic features, systemic inflammation markers (C-reactive protein, albumin, and 13 cytokines), and survival were analyzed. High serum tKRT18, aKRT18, and nKRT18 levels showed association with a higher extent of tumor necrosis, distant metastasis, and increased levels of several markers of systemic inflammation, including CXCL8. High serum tKRT18 (multivariable HR 1.94, 95% CI 1.28-2.95, p = .002) and nKRT18 (multivariable HR 1.87, 95% CI 1.24-2.82, p = .003) levels were associated with poor overall survival independent of potential confounding factors. Our results show that tumor necrosis in CRC contributes to serum levels of KRT18 fragments, and both necrosis and KRT18 levels associate with systemic inflammation. Moreover, we show that serum tKRT18 and nKRT18 levels have independent prognostic value in CRC. Our observations confirm the link between cell death and systemic inflammation.

Prognostic value of non-invasive serum Cytokeratin 18 detection in gastrointestinal cancer: a meta-analysis

Background: Gastrointestinal cancer is one of the most common neoplasms. Cytokeratin 18(CK18) is widely expressed in many different organs and cancers. Emerging data suggested conflicting results about the role of CK18 during carcinogenesis. The aim of this study is to systematically review the prognostic value of circulating CK18 (M65) and caspase-Cleaved CK18 (M30) in digestive cancers.

Materials and Methods: We searched major database for manuscripts reporting the effect of pretreatment CK18 on survival of digestive cancer patients. Revman5.3 and R were the software used for analysis. Pooled multivariable-adjusted hazard ratios (HR) for overall survival (OS) were calculated in all patients and many different subgroup analyses by stratifying on tumor type, metastasis stage, and ethnicity.

Results: 11 original studies were included for analysis. A low level of M30 and M65 were shown to be a protective factor for all cancer patients (HR 0.49, 95%CI 0.33-0.73, P=0.0003; HR 0.48, 95% CI 0.32-0.70, P =0.0001, respectively). The low M30 remained to be a protective factor for metastasized cancer patients while M65 had no statistically significant correlation with prognosis.

Conclusions: Non-invasive total and cleaved CK18 level detection by ELISA could be potentially a useful predictor of prognosis of digestive cancer patients. Further studies are warranted to investigate the molecular mechanisms of CK18.

Cathelicidin Suppresses Colon Cancer Metastasis via a P2RX7-Dependent Mechanism

The antimicrobial peptide cathelicidin inhibits development of colitis-associated colon cancer. However, the role of cathelicidin in colon cancer metastasis remains unknown. We hypothesized that cathelicidin is effective in inhibiting colon cancer metastasis. Human colon cancer HT-29 cells were injected intravenously into nude mice. Control HA-tagged adeno-associated virus (HA-AAV) or cathelicidin-overexpressing AAV (CAMP-HA-AAV) were injected intravenously into nude mice on the same day. Four weeks later, the nude mice were assessed for lung and liver metastases. Human colon cancer SW620 cells were used to study the effect of cathelicidin on cell migration and cytoskeleton. Incubation of SW620 cells with cathelicidin dose-dependently reduced cell migration, disrupted cytoskeletal structure, and reduced βIII-tubulin (TUBB3) mRNA expression. The addition of the P2RX7 antagonist KN62, but not the FPRL1 antagonist WRW4, prevented the LL-37-mediated inhibition of cell migration and TUBB3 mRNA expression. The CAMP-HA-AAV-overexpressing group showed significantly reduced human CK20 protein (by 60%) and TUBB3 mRNA expression (by 40%) in the lungs and liver of the HT-29-loaded nude mice, compared to the HA-AAV control group. Intraperitoneal injection of KN62 reversed the CAMP-HA-AAV-mediated inhibition of human CK20 and TUBB3 expression in the lungs and liver of HT-29-loaded nude mice. In conclusion, cathelicidin inhibits colon cancer metastasis via a P2RX7-dependent pathway.

THE ROLE OF SERUM CK-18, MMP-9 AND TIPM-1 LEVELS IN PREDICTING R0 RESECTION IN PATIENTS WITH GASTRIC CANCER

Background:

Gastric cancer is the 3^rd most common cause of death in men and the 5^th common in women worldwide. Today, surgery is the only curative therapy. Currently available advanced imaging modalities can predict R0 resection in most patients, but it can only be detected with certainty in the perioperative period.

Aim:

To determine the role of serum CK18, MMP9, TIMP1 levels in predicting R0 resection in patients with gastric cancer.

Methods:

Fifty consecutive patients scheduled for curative surgery with gastric adenocarcinoma diagnosed between 2013-2015 were included. One ml of blood was taken from the patients to analyze CK18, MMP9 and TIMP1.

Results:

CK18, MMP9 and TIMP1 levels were positively correlated with pathological N and the stage (p<0,05). CK-18, MMP-9 and TIMP-1 averages in positive clinical lymph nodes and in clinical stage 3, were found to be higher than the averages of those with negative clinical lymph nodes and in clinical stage 2 (p<0,05).

Conclusion:

Although serum CK-18, MMP-9 and TIMP-1 preoperatively measured in patients scheduled for curative surgery did not help to evaluate gastric tumor resectability, they were usefull in predicting N3-stage.

The efficacy of serum cell death biomarkers for diagnosing biliary tract cancer

In this study, we determined the efficacy of the cell death biomarker cytokeratin 18 for diagnosing biliary tract cancer (BTC). We recruited 36 patients with BTC (Malignant group) and 45 patients with benign biliary tract disease (Benign group) for this study. We used M30 and M65 as cell death biomarkers. M30 levels indicate apoptosis, and M65 levels indicate both apoptosis and necrosis. M30 and M65 levels were significantly higher in the Malignant group than in the Benign group (142.4 ± 117.0 vs 48.9 ± 71.2 U/l, P < 0.001; 1513.3 ± 837.4 vs 882.2 ± 831.2 U/l, P = 0.001). The diagnosability of M30 was the highest of the four markers (CEA, CA19-9, M30, M65) (cut-off value: 74.429 U/l, sensitivity: 72.2%, specificity: 77.1%, AUC: 0.771). The sensitivity of M30 (cut-off value: 74.429 U/l) was significantly higher than that of biliary cytology (76% (19/25) vs 12% (3/25), P < 0.001), and the accuracy of M30 was significantly higher than that of biliary cytology (78.3% (36/46) vs 52.2% (24/46), P = 0.015). The sensitivity of M30 (cut-off value: 74.429 U/l) was significantly higher than that of biliary cytology and brush cytology (72.4% (21/29) vs 24.1% (7/29), P < 0.001). In conclusion, cell death biomarkers were increased in patients with BTC, and M30 could efficiently diagnose BTC.

Cytokeratin-18 fragments predict treatment response and overall survival in gastric cancer in a randomized controlled trial

BACKGROUND

Gastric cancer is common malignancy and exhibits a poor prognosis. At the time of diagnosis, the majority of patients present with metastatic disease which precludes curative treatment. Non-invasive biomarkers which discriminate early from advanced stages or predict the response to treatment are urgently required. This study explored the cytokeratin-18 fragment M30 and full-length cytokeratin-18 M65 in predicting treatment response and survival in a randomized, placebo-controlled trial of advanced gastric cancer.

METHODS

Patients enrolled in the SUN-CASE study received sunitinib or placebo as an adjunct to standard therapy with leucovorin (Ca-folinate), 5-fluorouracil, and irinotecan in second or third line. Treatment response rates, progression-free survival and overall survival were assessed during a follow-up period of 12 months. Cytokeratin-18 fragments were analyzed in 52 patients at baseline and day 14 of therapy.

RESULTS

Levels of M30 correlated with the presence of metastasis and lymph node involvement and decreased significantly during chemotherapy. Importantly, baseline levels of M30 were significantly higher in patients who failed therapy. In addition, patients who did not respond to treatment were also identifiable at day 14 based on elevated M30 levels. By stepwise regression analysis, M30 at day 14 was identified as independent predictor of treatment response. Likewise, serum levels of full-length cytokeratin-18 M65 at baseline also correlated with treatment failure and progression-free survival. The addition of sunitinib did not exert any effects on serum levels of M30 or M65.

CONCLUSION

The cytokeratin-18 fragment M30 at day 14 identifies patients that fail to second- or third-line therapy for advanced gastric cancer. Validation of this non-invasive biomarker in gastric cancer is warranted.

Cell death markers in patients with cirrhosis and acute decompensation

The aims of this study were to determine the role of cell death in patients with cirrhosis and acute decompensation (AD) and acute on chronic liver failure (ACLF) using plasma-based biomarkers. The patients studied were part of the CANONIC (CLIF Acute-on-Chronic Liver Failure in Cirrhosis) study (N = 337; AD, 258; ACLF, 79); additional cohorts included healthy volunteers, stable patients with cirrhosis, and a group of 16 AD patients for histological studies. Caspase-cleaved keratin 18 (cK18) and keratin 18 (K18), which reflect apoptotic and total cell death, respectively, and cK18:K18 ratio (apoptotic index) were measured in plasma by enzyme-linked immunosorbent assay. The concentrations of cK18 and K18 increased and the cK18:K18 ratio decreased with increasing severity of AD and ACLF (P < 0.001, respectively). Alcohol etiology, no previous decompensation, and alcohol abuse were associated with increased cell death markers whereas underlying infection was not. Close correlation was observed between the cell death markers and, markers of systemic inflammation, hepatic failure, alanine aminotransferase, and bilirubin, but not with markers of extrahepatic organ injury. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining confirmed evidence of greater hepatic cell death in patients with ACLF as opposed to AD. Inclusion of cK18 and K18 improved the performance of the CLIF-C AD score in prediction of progression from AD to ACLF (P < 0.05).

CONCLUSION

Cell death, likely hepatic, is an important feature of AD and ACLF and its magnitude correlates with clinical severity. Nonapoptotic forms of cell death predominate with increasing severity of AD and ACLF. The data suggests that ACLF is a heterogeneous entity and shows that the importance of cell death in its pathophysiology is dependent on predisposing factors, precipitating illness, response to injury, and type of organ failure. (Hepatology 2018;67:989-1002).

The Role of Serum CK18, TIMP1, and MMP-9 Levels in Predicting R0 Resection in Patients with Gastric Cancer

Gastric cancer is the third most common cause of death in men and the fifth common cause of death in women worldwide. Currently, available advanced imaging modalities can predict R0 resection in most patients in the perioperative period. The aim of this study is to determine the role of serum CK18, MMP-9, and TIMP1 levels in predicting R0 resection in patients with gastric cancer. Fifty consecutive patients scheduled for curative surgery with gastric adenocancer diagnosis between 2013 and 2015 were included in the study. One milliliter of blood was taken from the patients included in the study to examine CK18, MMP-9, and TIMP1. CK18, MMP-9, and TIMP1 levels were positively correlated with pathological N and the stage (P < 0.05). The CK18, MMP-9, and TIMP1 averages of those with positive clinical lymph nodes and those in clinical stage 3 were found to be higher than the averages of those with negative clinical lymph nodes and those in clinical stage 2 (P < 0.05). Although serum CK18, MMP-9, and TIMP1 preop measurements in patients scheduled for curative surgery due to gastric adenocarcinoma did not help to gain any idea of tumor resectability, we concluded that our study had valuable results in significantly predicting N3 stage.

MicroRNA profiles during galectin-9-induced apoptosis of pancreatic cancer cells

Pancreatic cancer is the eighth-leading cause of cancer-associated mortality in males and the ninth-leading cause in females worldwide. Even when diagnosed early enough to be potentially resectable, the prognosis of invasive pancreatic cancer is poor. Galectin-9 (Gal-9) is a tandem-repeat type galectin that has recently been demonstrated to possess an anti-proliferative effect on cancer cells. Therefore, the present study evaluated the effects of Gal-9 on the proliferation of human pancreatic cancer cells and examined the microRNAs that are associated with the antitumor effects of Gal-9. Gal-9 suppressed the proliferation of multiple pancreatic cancer cell lines. In addition, Gal-9 treatment increased the levels of caspase-cleaved keratin 18 and the expression of cytochrome c in pancreatic cancer cell lines. This data suggests that Gal-9 induces intrinsic apoptosis in pancreatic cancer cell lines through the caspase-dependent and caspase-independent pathways. In addition, Gal-9 reduced the expression levels of phosphorylated epidermal growth factor receptor and numerous receptor tyrosine kinases (RTKs). In conclusion, Gal-9 may suppress the growth of human pancreatic cancer cells in vitro. These findings suggest that Gal-9 may be a new therapeutic agent for the treatment of pancreatic cancer.

First-in-human phase I study of SOR-C13, a TRPV6 calcium channel inhibitor, in patients with advanced solid tumors

Introduction This was an open-label, dose escalation (3 + 3 design), Phase I study of SOR-C13 in patients with advanced tumors of epithelial origin. Primary objectives were to assess safety/tolerability and pharmacokinetics. Secondary goals were to assess pharmacodynamics and efficacy of SOR-C13. Methods SOR-C13 was administered IV QD on days 1-3 and 8-10 of a 21-day cycle. Doses were 2.75 and 5.5 mg/kg (20-min infusion) and 1.375, 2.75, 4.13 and 6.2 mg/kg (90-min infusion). Toxicity was assessed by National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Dose limiting toxicity (DLT) was assessed within the first treatment cycle. Tumors were evaluated, using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, after two cycles. Results Twenty-three patients were treated. No drug-related serious adverse events occurred. DLTs occurred in six patients: asymptomatic, drug-related, transient Grade 2 hypocalcemia (4 patients), and unrelated Grade 3 anemia and Grade 3 atrial fibrillation, 1 patient each. Calcium and vitamin D supplementation eliminated further Grade 2 hypocalcemia. One Grade 3 treatment emergent adverse event, urticaria, was definitely related to SOR-C13. Four possibly drug-related, Grade 3 events (alanine aminotransferase and aspartate aminotransferase elevation, headache, and hypokalemia) were observed. Of 22 evaluable patients, 54.5% showed stable disease ranging from 2.8 to 12.5 months. The best response was a 27% reduction in a pancreatic tumor with a 55% reduction in CA19-9 levels at 6.2 mg/kg. Conclusion SOR-C13 was safe and tolerated up to 6.2 mg/kg. The Maximal Tolerated Dose (MTD) was not established. Stable disease suggested antitumor activity.

Serum cell death biomarker mirrors liver cancer regression after transarterial chemoembolisation

BACKGROUND

Hepatocellular carcinoma (HCC) represents an increasing health problem with limited therapeutic options. In patients with intermediate disease stage, transarterial chemoembolisation (TACE) is widely applied. Treatment response is routinely assessed by imaging techniques according to the international response evaluation criteria in solid tumours (RECIST), which consider tumour regression or additionally tumour necrosis (modified RECIST). Evaluation of treatment response, however, by these methods is time- and cost-intensive and usually performed at earliest several months following TACE.

AIM

To investigate the suitability of novel non-invasive cell death biomarkers for an earlier prediction of TACE response.

METHODS

We analysed activation of pro-apoptotic caspases and the proteolytic cleavage of the caspase substrate CK-18 in liver tissues and sera from HCC patients by immunohistochemistry, a luminometric substrate assay and ELISA.

RESULTS

Both caspase activity and caspase-cleaved CK-18 fragments were elevated in HCC patients compared to healthy controls. CK-18 serum levels significantly increased during the first 3 days and peaked at day two following TACE. Interestingly, we found significant differences in CK-18 levels between patients with and without tumour regression. Detection of CK-18 fragments revealed a promising performance for the early prediction of TACE response with an area under the curve value of 0.76.

CONCLUSIONS

Caspase-cleaved CK-18 levels mirror liver cancer regression and allow an earlier prediction of TACE response. The concordance with mRECIST suggests that the detection of CK-18 levels immediately after TACE might be used as a short-term decision guide to continue or change HCC therapy.

Monodisperse magnetic mesoporous silica microspheres facilitate the studies of gastric cancer-specific peptides in sera

The prognosis of gastric cancer remains poor despite the recent improvements in therapies.

Galectin-9 suppresses cholangiocarcinoma cell proliferation by inducing apoptosis but not cell cycle arrest

Cholangiocarcinoma is the most common biliary malignancy and the second most common hepatic malignancy after hepatocellular carcinoma (HCC). Galectin-9 (Gal-9) is a tandem-repeat-type galectin that has recently been shown to exert antiproliferative effects on cancer cells. Therefore, the present study evaluated the effects of Gal-9 on the proliferation of human cholangiocarcinoma cells in vitro as well as the microRNAs (miRNAs) associated with the antitumor effects of Gal-9. Gal-9 suppressed the proliferation of cholangiocarcinoma cell lines in vitro and the growth of human cholangiocarcinoma cell xenografts in nude mice. Our data further revealed that Gal-9 increased caspase‑cleaved keratin 18 (CCK18) levels, and the expression of cytochrome c increased in Gal-9-treated cholangiocarcinoma cell lines. These data suggested that Gal-9 induced cholangiocarcinoma cell apoptosis via the intrinsic apoptosis pathway mediated by caspase-dependent or -independent pathways. In addition, Gal-9 reduced the phosphorylation of the epidermal growth factor receptor (EGFR), insulin-like growth factor and insulin-like growth factor-1 receptor (IGF-1R), hepatocyte growth factor receptor and fibroblast growth factor receptor 3 (FGFR3). These findings suggest that Gal-9 can be a candidate of therapeutic target in the treatment of cholangiocarcinoma.

Percentage Change in Plasma Cytokeratin 18 Is Associated with Clinical Outcomes in Patients Receiving Pemetrexed and Carboplatin for the Adenocarcinoma Subtype of NSCLC

BACKGROUND

The adenocarcinoma subtype of non-small cell lung cancer (adeno-NSCLC) is routinely treated with chemotherapy if patients do not have molecular aberrations such as epidermal growth factor receptor mutations or anaplastic lymphoma kinase rearrangements. There are currently no validated biomarkers that can predict if patients will gain clinical benefit from chemotherapy, leading to a majority of patients receiving many cycles of unnecessary chemotherapy. We hypothesized that the percentage rise in plasma caspase-cleaved cytokeratin 18 (cCK18) and total cytokeratin 18 (tCK18) assessed before and after chemotherapy correlates with the radiological response to chemotherapy.

METHODS

Plasma samples from 40 patients with stage IV adeno-NSCLC, treated with first-line chemotherapy with carboplatin (AUC5) plus pemetrexed (500 mg/m(2)), were collected prior to chemotherapy and 48 h after treatment. ELISA was used to quantify cCK18 and tCK18.

RESULTS

The male-to-female ratio was 3:1, and the median age of patients was 63 years. Patients who had a clinical benefit (complete response, partial response or stable disease) at the first radiological assessment following chemotherapy had a significantly higher percentage change in plasma tCK18 levels compared to those who had no clinical benefit, i.e. progressive disease (69.5 ± 75.1 vs. 25.3 ± 30.9%, respectively; p = 0.042). The receiver operating characteristic area was 0.712 (p = 0.039). There was an increase in the percentage change in cCK18 in patients with clinical benefit compared to those without clinical benefit but this was not statistically significant (57.6 ± 112.8 vs. 24.38 ± 45.1%, respectively; p = 0.85).

CONCLUSIONS

The percentage change in plasma tCK18 levels before and after the first cycle of pemetrexed and carboplatin chemotherapy is associated with clinical benefit. If validated in larger cohorts, this test can be used to identify patients unlikely to respond to treatment who can thus be offered alternative treatments or entry into clinical trials.

Diagnostic value of protein chips constructed by lung-cancer-associated markers selected by the T7 phage display library

Background

Traditional diagnostic technology with tumor biomarkers is inefficient, expensive and requires a large number of serum samples. The purpose of this study was to construct human lung cancer protein chips with new lung cancer biomarkers screened by the T7-phage display library, and improve the early diagnosis rate of lung cancer.

Methods

A T7-phage cDNA display library was constructed of fresh samples from 30 lung cancer patients. With biopanning and high-throughput screening, we gained the immunogenic phage clones from the cDNA library. The insert of selected phage was blasted at GeneBank for alignment to find the exact or the most similar known genes. Protein chips were then constructed and used to assay their expression level in lung cancer serum from 217 cases of lung cancer groups:80 cases of benign lung disease and 220 healthy controls.

Results

After four rounds of Biopanning and two rounds of enzyme-linked immunosorbent assay, 12 phage monoclonal samples were selected from 2880 phage monoclonal samples. After blasting at GeneBank, six similar genes were used to construct diagnostic protein chips. The protein chips were then used to assay expression level in lung cancer serum. The expression level of six genes in lung cancer groups was significantly higher than those in the other two groups (P < 0.05).

Conclusions

In this study, we successfully constructed diagnostic protein chips with biomarkers selected from the lung cancer T7-phage cDNA library, which can be used for the early screening of lung cancer patients.

Plasma N-acetyl-glucosaminidase in advanced gastro-intestinal adenocarcinoma correlates with age, stage and outcome

BACKGROUND

N-acetyl-glucosaminidase (NAG) is a potential marker of genotoxicity. We retrospectively analyzed plasma NAG and clinico-pathologic features in advanced gastrointestinal adenocarcinoma patients.

METHODS

Plasma from 118 patients and 51 healthy volunteers was analyzed for associations between NAG levels and age, disease presence, stage, treatment responses and survival.

RESULTS

Pretreatment NAG correlated with age but was independently increased in metastatic versus locally advanced disease, particularly in gastric/esophageal patients. NAG was also associated with reduced overall survival. In subgroup analysis, increased NAG activity between day 1 and 2 of chemotherapy cycle 1 correlated with treatment response.

CONCLUSION

We demonstrated that NAG correlates with gastrointestinal cancer outcomes. Further studies are required to determine if plasma markers of genotoxicity can be useful for disease monitoring.

Human chorionic gonadotropin decreases human breast cancer cell proliferation and promotes differentiation

Human chorionic gonadotropin (hCG) is a glycoprotein produced by placental trophoblasts. Previous studies indicated that hCG could be responsible for the pregnancy-induced protection against breast cancer in women. It is reported that hCG decreases proliferation and invasion of breast cancer MCF-7 cells. Our research also demonstrates that hCG can reduce the proliferation of MCF-7 cells by downregulating the expression of proliferation markers, proliferating cell nuclear antigen (PCNA), and proliferation-related Ki-67 antigen (Ki-67). Interestingly, we find here that hCG elevates the state of cellular differentiation, as characterized by the upregulation of differentiation markers, β-casein, cytokeratin-18 (CK-18), and E-cadherin. Inhibition of hCG secretion or luteinizing hormone/hCG receptors (LH/hCGRs) synthesis can weaken the effect of hCG on the induction of cell differentiation. Furthermore, hCG can suppress the expression of estrogen receptor alpha. hCG activated receptor-mediated cyclic adenosine monophosphate/protein kinase A signaling pathway. These findings indicated that a protective effect of hCG against breast cancer may be associated with its growth inhibitory and differentiation induction function in breast cancer cells.

Serum programmed cell death protein 5 (PDCD5) levels is upregulated in liver diseases

Intracellular protein molecules are detected in the blood following release from damaged cells. PDCD5 is widely expressed in most types of normal human tissue and is unregulated in cells undergoing apoptosis. It is therefore hypothesized that release of PDCD5 into the circulation might be a specific marker of apoptosis. In this study, a sandwich ELISA was developed for quantification of soluble PDCD5 protein and used to investigate serum PDCD5 levels in liver diseases. The highest levels of PDCD5 were detected in acute icteric hepatitis (AIH) patients compared with normal subjects and other detected liver diseases, such as chronic active hepatitis B (CAHB), chronic persistent hepatitis B (CPHB) and and liver cirrhosis (LC). Increased PDCD5 levels correlated well with ALT and AST in AIH and CAHB patients. In patients with CPHB, increased PDCD5 levels correlated well with AST, TBI, DBIL, and IBIL. In LC patients, PDCD5 levels correlated well with AST/ALT and DBIL. More importantly, increased PDCD5 levels were also observed in patients with normal ALT or AST levels. These data demonstrate a correlation between increased levels of PDCD5 in serum and liver disease progression and indicate the potential utility of serum PDCD5 as a biomarker for monitoring liver injury.

Clinical significance of serum M30 and M65 levels in metastatic pancreatic adenocarcinoma

M30 and M65 are relatively new assays that detect different circulating forms of the epithelial cell structural protein cytokeratin 18. This study was conducted to investigate the serum levels of M30 and M65 in patients with metastatic pancreatic adenocarcinoma (MPA) and the relationship with tumor progression and known prognostic parameters. Twenty-six patients with MPA were investigated. Serum samples were obtained on first admission before treatment and follow-up. Both serum M30 and M65 levels were determined using enzyme-linked immunosorbent assay. The median age at diagnosis was 59 years, range 32-80 years; 14 patients were men. All patients had metastatic stage, and most (n = 21, 81%) had hepatic metastasis. The baseline levels of both serum M30 and serum M65 were significantly higher in patients with MPA than those in the control group (p < 0.001, for both assays). Serum M65 level was only significantly higher in the patients with elevated serum LDH levels than in others with normal serum LDH levels (p = 0.03). For serum M30 levels, no correlation was found. The significant relationship was found between the serum levels of M30 and M65 (r(s) = 0. 926, n = 26, p < 0.001, Spearman's correlation). The median survival for all patients was 31.7 ± 2.2 weeks (95% CI = 27.31-36.08). Although only the serum LDH level was found to be a significant prognostic factor (p = 0.01), neither serum M30 nor serum M65 had significant effect on survival (p = 0.28 and p = 0.15, respectively). In conclusion, although both serum levels of M30 and M65 assays were found to be of diagnostic value, no predictive and prognostic values were determined in MPA patients.

Can determination of circulating endothelial cells and serum caspase-cleaved CK18 predict for response and survival in patients with advanced non-small-cell lung cancer receiving endostatin and paclitaxel-carboplatin chemotherapy? a retrospective study

INTRODUCTION

Early prediction of the efficacy of a combination of an antiangiogenic drug with cytotoxic chemotherapy is a significant challenge. In that regard, circulating endothelial cells (CECs) and cytokeratins (CKs) seem to reflect their roles in both tumor angiogenesis and tumor cell death.

METHODS

Patients with advanced, previously untreated non-small-cell lung cancer were randomly assigned to an endostatin treatment group (paclitaxel + carboplatin + endostatin) and a control group (paclitaxel + carboplatin + placebo). A total of 122 patients were evaluated, of whom 107 had measurements of blood CECs, CK8, caspase-cleaved CK18 (ccCK18), and uncleaved CK18 (CK18) before and at weeks 3 and 6 of treatment, respectively.

RESULTS

Higher baseline CECs in patients with a tumor response (partial remission + stable disease, p = 0.002 for the entire group; p = 0.000 for the treatment group) were observed. The number of CECs decreased significantly after endostatin treatment (p = 0.000), whereas CK levels increased. Increased levels of ccCK18 and CK18, but not CK8, reached significance (p = 0.001 and p = 0.048, respectively) when compared with the baseline. Tumor response showed a strong correlation with reduction of CECs (p = 0.000) and increase of ccCK18 (p = 0.040) after endostatin therapy. Cutoff values of changes of CECs and ccCK18 for prediction of survival were 0.58/μl and 19.6 ng/ml, respectively. Reduction of CECs and increase of ccCK18 significantly correlated with longer median survival (p = 0.013 and p = 0.016 for progression-free survival; p = 0.009 and p = 0.012 for overall survival, respectively).

CONCLUSIONS

CECs and CKs could be biomarkers for selecting patients with non-small-cell lung cancer who will benefit from treatment with endostatin in combination with paclitaxel plus carboplatin.

The prognostic significance of the increase in the serum M30 and M65 values after chemotherapy and relationship between these values and clinicopathological factors in patients with advanced gastric cancer

In some studies, the prognostic and predictive significance of M30 and M65 has been reported to detect response to chemotherapy. In the present study, we aimed at determining the changes of serum M30 and M65 values after chemotherapy and the impact of these values on treatment response and progression-free survival (PFS) and overall survival (OS) of patients with advanced gastric cancer. A total of 31 patients with advanced gastric cancer was included. M30 and M65 values were measured by a quantitative enzyme-linked immunosorbent assay (ELISA) method in serum samples before and 48 h after the first chemotherapy cycle. Pre- and postchemotherapy values of M30 and M65 were compared. The difference between the mean values of serum M30 and M65 before and after chemotherapy was calculated and the prognostic significance of changes for survival was evaluated by univariate and multivariate analysis. Logistic regression analysis was performed to predict response to chemotherapy. Serum M30 and M65 levels were found to be increased significantly after chemotherapy (M30, 582.7 ± 111.5 U/l [pre mean] vs. 983.3 ± 214.1 U/l [post mean], p = 0.01; M65, 2,061.7 ± 431.2 U/l [pre mean] vs. 2,646.3 ± 433.1 U/l [post mean], p = 0.003). Means of the differences of M30 and M65 levels before and 48 h after chemotherapy were 400.5 ± 190 U/l ([M30-difference] M30-D) and 584.6 ± 335.4 U/l (M65-D), respectively. Patients with serum M30-D of <400.5 U/l had better median PFS and OS times than patients with M30-D >400.5 U/l (PFS, 9.9 vs. 4.3 months, p = 0.018 and OS, 13.6 vs. 8.1 months, p = 0.029). In addition, median PFS and OS intervals in patients with serum M65-D > 584.6 U/l were significantly worse than those of patients whose M65-D was lower than or equal to 584.6 U/l (4.1 vs. 11.4 months for PFS, p = 0.002 and 5.7 vs. 13.6 months for OS, p = 0.005). Patients with values above M30-D and M65-D had a better tumor response compared with patients with values below M30-D and M65-D (p = 0.02 and p = 0.006, respectively). In the logistic regression analysis, only M65-D was significantly found to be an independent factor in predicting response to chemotherapy (p = 0.018, OR:1.4). However, only M30 levels after chemotherapy were found to be an independent prognostic factor for PFS in the multivariate analysis. These results showed for the first time that both M30 and M65 in serum samples of patients with advanced gastric cancer were elevated 48 h after chemotherapy and these were poor prognostic factors for both PFS and OS of patients. Moreover, increased serum M65 levels after chemotherapy can be predict tumor response.

A potential association between Helicobacter pylori CagA EPIYA and multimerization motifs with cytokeratin 18 cleavage rate during early apoptosis

BACKGROUND AND AIMS

Helicobacter pylori is a highly diverse pathogen, which encounters epithelial cells as the initial defense barrier during its lifelong infection. The structure of epithelial cells can be disrupted through cleavage of microfilaments. Cytokeratin 18 (CK18) is an intermediate filament, the cleavage of which is considered an early event during apoptosis following activation of effector caspases.

METHODS

Helicobacter pylori strains were isolated from 76 dyspeptic patients. cagA 3' variable region and CagA protein status were analyzed by PCR and western blotting, respectively. Eight hours post-co-culture of AGS cells with different H. pylori strains, flow cytometric analysis was performed using M30 monoclonal antibody specific to CK18 cleavage-induced neo-epitope.

RESULTS

Higher rates of CK18 cleavage were detected during co-culture of AGS cells with H. pylori strains bearing greater numbers of cagA EPIYA-C and multimerization (CM) motifs. On the other hand, H. pylori strains with greater numbers of EPIYA-B relative to EPIYA-C demonstrated a decrease in CK18 cleavage rate. Thus, H. pylori-mediated cleavage of CK18 appeared proportional to the number of CagA EPIYA-C and CM motifs, which seemed to be downplayed in the presence of EPIYA-B motifs.

CONCLUSIONS

Our observation associating the heterogeneity of cagA variants with the potential of H. pylori strains in the induction of CK18 cleavage as an early indication of apoptosis in gastric epithelial cells supports the fact that apoptosis may be a type-specific trait. However, additional cagA-targeted experiments are required to clearly identify the role of EPIYA and CM motifs in apoptosis and/or the responsible effector molecules.

Multi-level evidence that circulating CK18 is a biomarker of tumour burden in colorectal cancer

Background:

Circulating total cytokeratin 18 (tCK18) and/or caspase cleaved cytokeratin 18 (cCK18) (measured by M65 and M30 enzyme-linked immunosorbent assays (ELISAs), respectively) are used as pharmacodynamic (PD) biomarkers of epithelial cell death in clinical trials. Having validated these ELISAs, we assessed their utility in colorectal cancer (CRC).

Methods:

We applied the assays in several settings: 53 controls; 97 patients undergoing surgery and 74 patients with metastatic CRC undergoing chemotherapy (55 first line; 56 patients with repeated sampling through chemotherapy). Prognostic significance was evaluated using Kaplan–Meier life tables and Cox models; PD utility was assessed by analysis of repeated measures.

Results:

Median cCK18 and tCK18 levels were elevated in patients with cancer (both P=0.0001), and among cancer patients, there were increasing trends from early to advanced stages (both P_trends=0.0001). Increasing tCK18 predicted for reduced survival after surgery with curative intent (adjusted hazard ratio (HR) for doubling in concentration 1.77, 95% CI: 1.04, 3.01) and after first-line chemotherapy in metastatic disease (adjusted HR per doubling in concentration=1.78, 95% CI: 1.37, 2.30). In patients with progressive disease during chemotherapy, repeated sampling revealed profiles with high baselines and progressive upwardly increases after cycle 1.

Conclusion:

This study provides evidence for cytokeratin 18 (CK18) as a prognostic and PD biomarker in patients with CRC and supports continued deployment of circulating CK18 in biomarker-enhanced trials.

Prognostic importance of markers for inflammation, angiogenesis and apoptosis in high grade glial tumors during temozolomide and radiotherapy

INTRODUCTION

Angiogenesis, inflammation and apoptosis have an important place in the carcinogenesis of high-grade gliomas (HGG). We evaluated the postoperative levels and the prognostic importance of tumor necrosis factor-alpha (TNFα), interleukin 6 (IL6), endoglin (CD105), vascular endothelial growth factor (VEGF), M65 and M30 as markers of inflammation, angiogenesis and apoptosis in patients with HGG.

METHODS AND RESULTS

Postoperative pretreatment sera were collected from 44 newly diagnosed patients with HGG. The control group was also consisted of 44 healthy people. The median age of all patients with HGG was 59 (range: 30-80). Temozolomide concurrent with radiotherapy was given to 37 patients. Thereafter 24 patients received consolidation temozolomide monotherapy. Mean chemotherapy cycle was 4.2. Progression free survival and overall survival were 6 (95% CI; 5.16-6.83) and 16 months (95% CI; 13.07-18.93) respectively in patients treated with concurrent chemoradiotherapy and consolidation chemotherapy. Relative to the control cohort endoglin (p = 0.000) and TNFα (p = 0.000) levels were significantly lower; however VEGF (p = 0.030) levels were higher in the patient group. In contrast, there were no significant change in IL-6 levels and the plasma apoptotic markers M65 (p = 0.085) and M30 (p = 0.292). In separate log rank tests, these biological markers did not correlate with survival.

DISCUSSION AND CONCLUSION

In HGG, a significant decrease in endoglin and TNFα levels was observed, while VEGF levels were significantly increased postoperatively. However, with the power from this patient population, no correlation with survival was observed.

Serum cytokeratin 18 as a biomarker for gastric cancer

Cytokeratin 18 (CK18) fragments are released into circulation during epithelial cell death. M30 (reflects caspase-cleaved CK18 fragment) and M65 (reflects total CK18 fragment) enzyme-linked immunosorbent assay (ELISA) detect circulating CK18 fragments released during caspase-dependent or total cell death, respectively; thus, CK18 has the potential of being a biomarker for epithelial cancers. In the present study, we investigated the serum levels of M30 and M65 in patients with gastric cancer, determined correlation of these levels with clinical features, and evaluated the usefulness of these enzymes as diagnostic and prognostic markers. We enrolled 54 gastric cancer patients and 12 healthy volunteers in this study. We measured the serum levels of M30 and M65 by quantitative ELISA. The levels of M30 and M65 in gastric cancer patients were significantly higher than those in healthy volunteers (P = 0.001, P < 0.001). The enzyme levels were elevated with the progress of gastric cancer. The sensitivity and specificity of M30 as a diagnostic marker were 67.5 and 90.9 %, respectively, and those of M65 were 70.1 and 90.9 %, respectively. The serum levels of M30 and M65 in patient with early gastric cancer were elevated in 38.1 and 66.7 %, respectively. Further, increased serum level of M65 is an independent indicator of poor prognosis (P = 0.036). The serum levels of M30 and M65 may be useful biomarkers for gastric cancer as diagnostic markers that can reflect the extent of cancer. Moreover, M65 levels can be used as a prognostic indicator.

Caspase-cleaved cytokeratin-18 and tumour regression in gastro-oesophageal adenocarcinomas treated with neoadjuvant chemotherapy

AIM: To examine cytokeratin-18 (CK-18) and caspase-cleaved CK-18 expression in tumours and correlate with clinicopathological outcomes including tumour regression grade (TRG) response.

METHODS: Formalin-fixed human gastro-oesophageal cancers were constructed into tissue microarrays. The first set consisted of 122 gastric/gastro-oesophageal cancer cases not exposed to neoadjuvant chemotherapy and the second set consisted of 97 gastric/gastro-oesophageal cancer cases exposed to pre-operative platinum-based chemotherapy. Expression of CK-18 and caspase-cleaved CK-18 was investigated using immunohistochemistry.

RESULTS: CK18 was commonly expressed in gastro-oesophageal tumours (92.6%). Fifty-six point seven percent of tumours previously exposed to neoadjuvant chemotherapy were positive for caspase-cleaved CK-18 expression compared to only 24.6% of tumours not previously exposed to neoadjuvant chemotherapy (P = 0.009). In patients who received neoadjuvant chemotherapy, caspase-cleaved cytokeratin-18 expression correlated with favourable TRG response (TRG 1, 2 or 3, P = 0.043).

CONCLUSION: This is the largest study to date of CK-18 and caspase-cleaved CK-18 expression in gastro-oesophageal tumours. We provide the first evidence that caspase-cleaved CK-18 predicts tumour regression with neoadjuvant chemotherapy.

Evaluation of cell death mechanisms induced by the vascular disrupting agent OXi4503 during a phase I clinical trial

Background:

OXi4503 is a tubulin-binding vascular disrupting agent that has recently completed a Cancer Research UK-sponsored phase I trial. Preclinical studies demonstrated early drug-induced apoptosis in tumour endothelial cells at 1–3 h and secondary tumour cell necrosis between 6 and 72 h.

Methods:

To capture both possible outcomes of OXi4503 treatment on cell death, plasma samples for analysis by M30 and M65 ELISAs, which measure different circulating forms of cytokeratin 18 as biomarkers of apoptosis and necrosis, respectively, were collected from patients entered into the trial at early (4/6 h) and later time points (24 h, day 8 and day 15).

Results:

OXi4503 induced a selective dose-dependent elevation in M30 antigen levels (apoptosis) at 4/6 h and a similar elevation in M65 antigen levels at 24 h (necrosis) consistent with its preclinical cell death profile. For the purposes of investigating potential biomarker relationships to patient characteristics, the trial population was divided into three groups based on radiological and clinical response: (a) early progression, (b) progressive disease and (c) stable disease (SD)/partial response. A significant increase in antigen concentrations was measured by M65 at 24 h in the SD group compared with the two other groups (P=0.015, mean increase 30.9%).

Conclusion:

These results provide pharmacodynamic evidence of drug mechanism of action in cancer patients and highlight the M65 ELISA as a potentially useful biomarker assay of response to OXi4503.

Bromelain-induced apoptosis in GI-101A breast cancer cells

Bromelain is a proteolytic enzyme extracted from the stems and the immature fruits of pineapple that was found to be antitumorigenic in different in vitro models. Bromelain has been reported to promote apoptosis, particularly in breast cancer cells, with the up-regulation of c-Jun N-terminal kinase and p38 kinase. Our study was designed to determine if bromelain could induce apoptosis in GI-101A breast cancer cells. GI-101A cells were treated with increasing concentrations of bromelain for 24 hours. The effect of bromelain for inducing cell death via activation of the apoptosis mechanism in GI-101A cells was further determined by using caspase-9 and caspase-3 assays along with the M30-Apoptosense assay to measure cytokeratin 18 (CK18) levels in the cytoplasm of the cultured cancer cells. A dose-dependent increase in the activities of caspase-9 and caspase-3 coinciding with elevation of CK18 levels was found in bromelain-treated cells compared with control cells. Furthermore, the apoptosis induction by bromelain was confirmed by DNA fragmentation analysis and 4,6'-diamino-2-phenylindole dihydrochloride fluorescence staining of the nucleus. Our results indicate an increase in apoptosis-related cell death in breast cancer cells with increasing concentrations of bromelain.

Effect of chymotrypsin C and related proteins on pancreatic cancer cell migration

Pancreatic cancer is a malignant cancer with a high mortality rate. The amount of chymotrypsin C in pancreatic cancer cells is only 20% of that found in normal cells. Chymotrypsin C has been reported to be involved in cancer cell apoptosis, but its effect on pancreatic cancer cell migration is unclear. We performed cell migration scratch assays and Transwell experiments, and found that cell migration ability was downregulated in pancreatic cancer Aspc-1 cells that overexpressed chymotrypsin C, whereas the cell migration ability was upregulated in Aspc-1 cells in which chymotrypsin C was suppressed. Two-dimensional fluorescence differential in gel electrophoresis/mass spectrometry method was used to identify the proteins that were differentially expressed in Aspc-1 cells that were transfected with plasmids to induce either overexpression or suppressed expression of chymotrypsin C. Among 26 identified differential proteins, cytokeratin 18 was most obviously correlated with chymotrypsin C expression. Cytokeratin 18 is expressed in developmental tissues in early stages of cancer, and is highly expressed in most carcinomas. We speculated that chymotrypsin C might regulate pancreatic cancer cell migration in relation to cytokeratin 18 expression.

Utilization of cytokeratin-based biomarkers for pharmacodynamic studies

Cytokeratin (CK)18 is a useful serum biomarker for the determination of cell death of epithelial-derived tumors (carcinomas). ELISAs are available for caspase-cleaved CK18 (M30) released from apoptotic cells, or total CK18 (M65) released by cells undergoing cell death by any cause. These assays have been demonstrated to have prognostic or predictive utility in various types of carcinomas. Encouraging data have been reported by different investigators with regard to the potential use of CK18 as a serum efficacy biomarker for monitoring therapy efficiency in carcinoma patients. The ratio of caspase-cleaved to total CK18 can be determined conveniently in serum or plasma using commercially available ELISA kits (M30-Apoptosense and M65 ELISA, Peviva AB, Bromma, Sweden). M30:M65 ratios potentially provide information as to whether tumor cells undergo apoptosis or necrosis. However, as discussed in this review, M30:M65 ratios should be interpreted with caution and, preferably, only be applied to samples that contain significant levels of CK18. We conclude that M30 and M65 biomarkers provide both quantitative and qualitative information on carcinoma cell death.

Serum M30 levels are associated with survival in advanced gastric carcinoma patients

BACKGROUND

Cytokeratin 18 (CK-18) is a cytoskeleton protein of epithelial cells which are released into the circulation during necrotic or apoptotic cell death. M30 detects caspase-cleaved neo-epitope of CK-18; whereas M 65 measures whole length intact protein. We aimed to evaluate the prognostic significance of serum M65 and M30 levels in patients with gastric carcinoma.

METHODS

Thirty eight patients with advanced disease were included in the study. Thirty-two healthy people were chosen as control group. Serum M65 and M30 levels were measured by quantitative ELISA method.

RESULTS

Serum M65 levels were found significantly elevated in patients compared to control group (385.7+/-280.6 vs. 200.2+/-164.5, p=0.002). Serum M30 levels were significantly increased in patients compared to the control group (204.6+/-245 vs. 106.5+/-17.5, p=0.03). Patients with metastatic disease had significantly higher levels of serum M30 compared to patients with locally advanced disease (267.1+/-296.1 vs. 102.3+/-53.2, p=0.03). Serum M30 and M65 levels were evaluated in respect to survival. Best cut-off value for the prediction of death for M30 antigen level was 83.8U/L. Patients with higher M30 levels had significantly shorter median survival compared to patients' lower serum M30 levels. However, there was no impact of serum M65 levels on survival. Serum M30 levels and clinical stage were found as the strongest variables with independent prognostic value for overall survival.

DISCUSSION

These results suggest that serum M65 and M30 levels were elevated in patients with advanced gastric carcinoma patients. Serum M30 levels can be helpful to predict tumor load and also survival.

Serum biomarkers of cell death for monitoring therapy response of gastrointestinal carcinomas

PURPOSE

Antitumour treatments are thought to exert their therapeutic efficacy mainly by induction of apoptosis in tumour cells. In epithelial cells, caspases, the key enzymes of apoptosis, cleave the intermediate filament protein cytokeratin (CK)-18 into specific fragments that are released into circulating blood and can be detected by a specific ELISA.

EXPERIMENTAL DESIGN

To investigate the use of CK-18 fragments as a potential biomarker for the treatment response, we examined the association of serum CK-18 levels and clinical response in 35 patients with gastrointestinal cancers.

RESULTS

While both cleaved and total CK-18 levels were intrinsically elevated in tumour patients, they were further increased during 5-fluorouracil (5-FU)-based therapy. Importantly, the increased levels of CK-18 could discriminate between patients with different clinical response. Cancer patients with a partial response or stable disease revealed a significantly higher increase of cleaved CK-18 during chemotherapy as compared to patients with progressive disease.

CONCLUSIONS

Our results suggest that detection of circulating caspase-cleaved CK-18 might be a useful serum biomarker for monitoring treatment response and should merit further evaluation in larger patient groups.

Considerations for the use of plasma cytokeratin 18 as a biomarker in pancreatic cancer

BACKGROUND

Enzyme-linked immunoassays of full-length (M65) and/or caspase-cleaved (M30) cytokeratin 18 (CK18) released from epithelial cells undergoing necrosis and/or apoptosis, respectively, may have prognostic or predictive biomarker utility in a range of solid tumour types. Characterisation of baseline levels of circulating full length and cleaved CK18 specifically in patients with pancreatic cancer.

METHODS

Plasma samples from 103 patients with pancreatic cancer stored at -80 degrees C were assayed for M65 and M30 levels. The median (inter-quartile range (IQR)) duration of plasma storage was 34 (23-57) months. Patients with metastatic disease (n=19) were found to have greater median (IQR) M65 levels (1145 (739-1698) U l(-1)) compared with the locally advanced (n=20; 748 (406-1150) U l(-1)) and resected (n=64; 612 (331-987) U l(-1)) patients (P=0.002). Elevated M65 levels were associated with poorer overall survival on univariate (P<0.001) but not multivariate (P=0.202) analysis. M65 concentrations also exhibited significant associations with concurrent serum-bilirubin levels (P<0.001) and the duration of plasma storage (P<0.001).

CONCLUSIONS

Baseline plasma CK18 levels in pancreatic cancer are affected by the presence of obstructive jaundice and prolonged plasma storage. Clinical biomarker studies utilising serial CK18 levels are warranted in pancreatic cancer, provided consideration is given to these potentially confounding factors.

Circulating cytokeratin 18 fragments and activation of dormant tumor cells in bone marrow of cancer patients

In cancer patients detection of systemic disease is of great importance to obtain prognostic information and to guide therapy. Bone marrow (BM) seems to be a common homing tissue for the early spread of tumor cells from various epithelial tumors; however, verification of the prognostic significance of BM-disseminated tumor cells (BM-DTCs), is restricted to breast cancer so far. These cells may be dormant for a long time, and signals triggering their activation leading to recurrence remain to be characterized. A recent study involving metastatic breast cancer patients reported that the shortest disease-free survival is correlated with cytokeratin (CK)-negative BM aspirates and that CK-positive BM-DTCs correspond to dormant tumor cells. Soluble CK fragments in serum including CK18 and 19 (measured as TPS and CYFRA 21-1, respectively) and caspase-cleaved CK18 are widely used to monitor tumor progression and response to therapy, actually indicating proliferation and/or necrotic/apoptotic cell death. In order to assess the source of the CK fragments, we used determinations of CK18 and caspase-cleaved CK18 fragments in serum samples before and after radical tumor surgery in colon cancer patients. Elevated serum concentrations of CK18 were found to persist in patients with a high incidence of BM-DTCs, and high perioperative levels of caspase-cleaved CK18 fragments were detected in patients with early relapses, respectively. These results indicate that in some patients at increased risk of recurrence disseminated cell populations exist that are responsible for the release of the bulk of CK fragments after removal of the apparently nonmetastatic tumor. In good agreement with the results in metastatic breast cancer patients, release of CK18 or 19 fragments by BM-DTCs seem to indicate disseminated tumor cells mainly in a dormant state, whereas caspase-cleaved CK18 may indicate skipping of this latent phase and early progression. Therefore, caspase cleavage of CKs in intact tumor cells seems to accompany or is involved in the differentiation leading from dormant to progressively active disseminated tumor cells. Release of respective CK fragments would result in an apparent clearing of CK-positive cells in BM, leaving malignant cells that have possibly undergone an epithelial-mesenchymal transition. Micrometastatic cancer cell lines derived from breast cancer patients were found to display loss of epithelial CK8, 18 and 19 as well as ectopic expression of vimentin as in mesenchymal cells. In conclusion, degradation of CKs may represent a marker indicating reactivation of dormant tumor cells in BM.