Comparison of neurone-specific enolase and pro-gastrin releasing peptide in the prognostic evaluation of small cell lung cancer patients

The prognostic value of the serum neuron specific enolase and lactate dehydrogenase in small cell lung cancer patients receiving first-line platinum-based chemotherapy

The aim of this study was to investigate the associations of serum levels of neuron-specific enolase (NSE), pro-gastrin releasing peptide (ProGRP), and lactate dehydrogenase (LDH) with clinical response and survival in small cell lung cancer (SCLC) patients receiving first-line platinum-based chemotherapy.One hundred thirty-six patients with SCLC were recruited in this study. All the patients received first-line platinum-based chemotherapy. Clinical efficacy was assessed according to Response Evaluation Criteria in Solid Tumors v1.1 criteria. Serum samples were collected from SCLC patients before chemotherapy. NSE, ProGRP, and LDH levels were measured by commercial electrochemiluminescence immunoassay, enzyme-linked immune sorbent assay, and kinetic spectrophotometric method, respectively.Overall response rate was 71.3% with 97 patients who achieved complete response (CR) +  partial response (PR). NSE and LDH level declined in patients who achieved CR + PR compared with patients in stable disease (SD) and progress disease (PD). Multivariate logistic regression analysis revealed that NSE > 50.324 ng/mL, stage ED, and distant metastases were independent risk factors for patients achieving CR + PR, and chemotherapy > 4 cycles was an independent protective factor in predicting CR + PR. Receiver operating characteristic (ROC) curves presented that expression of NSE, ProGRP, and LDH are of good predicting value for patients achieving CR + PR. Patients with a higher level of NSE and LDH presented worse progression-free survival and overall survival. In addition, multivariate Cox regression analysis showed that NSE level > 50.324 ng/mL and distant metastasis were independently correlated with worse OS.Serum NSE and LDH could be promising biomarkers for predicting therapy response and survival of SCLC patients receiving first-line platinum-based chemotherapy.

Study on biodistribution and radioimmunoimaging of (131)iodine-labeled monoclonal antibody D-D3 against progastrin-releasing peptide31-98 in tumor-bearing mouse

This study was aimed at investigating the biodistribution and radioimmunoimaging of (131)I-D-D3 in nude mice bearing different types of tumor xenografts. Radioiodination of the D-D3 antibody was performed with the chloramine-T method. The radiochemical purity was determined through thin-layer chromotography. (131)I-D-D3 was injected into healthy Kunming mice via a tail vein, and the %ID/g for various organs was obtained. Similarly, the %ID/g and tumor/nontumor tissue ratio of (131)I-D-D3 in nude mice bearing small cell lung cancer (SCLC) xenografts were obtained. Planar images of (131)I-D-D3 in tumor-bearing nude mice were acquired at different times after injection. The (131)I-D-D3 labeling rate was 86.56%  ± 3.8%. The radiochemical purity of (131)I-D-D3 was 99.27%  ± 0.6%. After 12 hours of incubation in 37°C water bath, the radiochemical purity was 97.64%  ±  0.5% and remained at 88.38% ± 0.4% after 48 hours. After being mixed with healthy human serum for 24 hours, the radiochemical purity was more than 64%. The metabolism of (131)I-D-D3 in healthy Kunming mice was consistent with a two-compartment model with first-order absorption; T(1/2α) and T(1/2β) were 0.25 and 37.89 hours, respectively. The %ID/g of (131)I-D-D3 in SCLC xenografts was much higher than those of other tissues at 48 hours after injection, and the tumor/nontumor tissue ratio also gradually increased with time. After 24 hours of injection, planar imaging was obtained, which clearly showed a contrasting tumor on the right armpit of nude mice bearing SCLC with high concentrations of radioactivity. Also, nude mice bearing gastric cancer showed similar results as that of the SCLC with a lower radioactivity level. No observable accumulation was observed in nude mice bearing pancreatic cancer or lung adenocarcinoma. The labeling rate and radiochemical purity of (131)I-D-D3 were high and stable. (131)I-D-D3 selectively accumulated at tumors that highly expressed progastrin-releasing peptide; therefore, it is a promising radioimmunoimaging reagent for SCLC.

Gastrin-releasing peptide: different forms, different functions

All forms of the neuropeptide gastrin-releasing peptide (GRP) are derived from the precursor proGRP1-125. Amidated GRP18-27, which together with amidated GRP1-27 was long thought to be the only biologically relevant product of the GRP gene, is involved in a multitude of physiological functions and acts as a mitogen, morphogen, and proangiogenic factor in certain cancers. Recently, GRP has been implicated in several psychiatric conditions, in the maintenance of circadian rhythm, in spinal transmission of the itch sensation, and in inflammation and wound repair. The actions of GRP are mediated by the GRP receptor. Over the last decade, nonamidated peptides derived from proGRP, such as the glycine-extended form GRP18-28 and recombinant and synthetic fragments from proGRP31-125, have been shown to be biologically active in a range of tissues and in cancer cell lines. While GRP18-28 acts via the GRP receptor, the identity of the receptor for proGRP31-125 and its fragments has not yet been established. Nonamidated fragments are also present in normal tissues and in various cancers. In fact, proGRP31-98 is the most sensitive serum biomarker in patients with small cell lung cancer and is a significant predictor of poor survival in patients with advanced prostate cancer.