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Inflammation is closely associated with cerebrovascular diseases, cardiovascular diseases, diabetes, and cancers, and it is accompanied by the development of autoantibodies in the early stage of inflammation-related diseases. Hence, it is meaningful to discover novel antibody biomarkers targeting inflammation-related diseases. In this study, Jumonji C-domain-containing 6 (JMJD6) was identified by the serological identification of antigens through recombinant cDNA expression cloning. In particular, JMJD6 is an antigen recognized in serum IgG from patients with unstable angina pectoris (a cardiovascular disease). Then, the serum antibody levels were examined using an amplified luminescent proximity homogeneous assay-linked immunosorbent assay and a purified recombinant JMJD6 protein as an antigen. We observed elevated levels of serum anti-JMJD6 antibodies (s-JMJD6-Abs) in patients with inflammation-related diseases such as ischemic stroke, acute myocardial infarction (AMI), diabetes mellitus (DM), and cancers (including esophageal cancer, EC; gastric cancer; lung cancer; and mammary cancer), compared with the levels in healthy donors. The s-JMJD6-Ab levels were closely associated with some inflammation indicators, such as C-reactive protein and intima-media thickness (an atherosclerosis index). A better postoperative survival status of patients with EC was observed in the JMJD6-Ab-positive group than in the negative group. An immunohistochemical analysis showed that JMJD6 was highly expressed in the inflamed mucosa of esophageal tissues, esophageal carcinoma tissues, and atherosclerotic plaques. Hence, JMJD6 autoantibodies may reflect inflammation, thereby serving as a potential biomarker for diagnosing specific inflammation-related diseases, including stroke, AMI, DM, and cancers, and for prediction of the prognosis in patients with EC.

Background: Atherosclerosis (AS) and tumours are the leading causes of death worldwide and share common risk factors, detection methods and molecular markers. Therefore, searching for serum markers shared by AS and tumours is beneficial to the early diagnosis of patients., Methods: The sera of 23 patients with AS-related transient ischaemic attack were screened by serological identification of antigens through recombinant cDNA expression cloning (SEREX), and cDNA clones were identified. Pathway function enrichment analysis was performed on cDNA clones to identify their biological pathways and determine whether they were related to AS or tumours. Subsequently, gene-gene and protein-protein interactions were performed and AS-associated markers would be discovered. The expression of AS biomarkers in human normal organs and pan-cancer tumour tissues were explored. Then, immune infiltration level and tumour mutation burden of various immune cells were evaluated. Survival curves analysis could show the expression of AS markers in pan-cancer., Results: AS-related sera were screened by SEREX, and 83 cDNA clones with high homology were obtained. Through functional enrichment analysis, it was found that their functions were closely related to AS and tumour functions. After multiple biological information interaction screening and the external cohort validating, poly(A) binding protein cytoplasmic 1 (PABPC1) was found to be a potential AS biomarker. To assess whether PABPC1 was related to pan-cancer, its expression in different tumour pathological stages and ages was screened. Since AS-associated proteins were closely related to cancer immune infiltration, we investigated and found that PABPC1 had the same role in pan-cancer. Finally, analysis of Kaplan-Meier survival curves revealed that high PABPC1 expression in pan-cancer was associated with high risk of death., Conclusions: Through the findings of SEREX and bioinformatics pan-cancer analysis, we concluded that PABPC1 might serve as a potential biomarker for the prediction and diagnosis of AS and pan-cancer., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Thymidylate synthase (TS) plays a major role in the response to 5-fluorouracil (5-FU) by binding directly to the 5-FU metabolite, 5-fluoro-dUMP (FdUMP). The change in the TS expression levels after 5-FU administration was examined in parallel to 5-FU responsiveness in six human gastric adenocarcinoma cell lines to elucidate the source of variability of 5-FU sensitivity. MKN-1, SH-10-TC and MKN-74 cells were more resistant to 5-FU than MKN-28, KATO III and MKN-45 cells. Western blotting analysis revealed that the 5-FU sensitivity of these cells did not correlate with the basal TS expression levels but did correlate with rapid detection of the TS-FdUMP complex after exposure to 5-FU. In 5-FU-resistant cells, very low levels of the TS-FdUMP complex early after 5-FU exposure were elevated by pretreatment with calpain inhibitors such as benzyloxycarbonyl-leucyl-leucinal (ZLLH), benzyloxycarbonyl-leucyl-leucyl-leucinal (ZLLLH) and ALLN, but not by other protease inhibitors. In contrast, ONO-3403, which causes calpain activation, stimulated downregulation of the TS-FdUMP complex in 5-FU-sensitive cells. The expression levels of calpastatin, an endogenous calpain inhibitor, were higher in 5-FU-sensitive cells than in 5-FU-resistant cells. ZLLH increased the 5-FU sensitivity of 5-FU-resistant cells, whereas ONO-3403 decreased the sensitivity of 5-FU-sensitive cells. In addition, knockdown of m-calpain by siRNA increased the 5-FU sensitivity in 5-FU-resistant cells, while knockdown of calpastatin reduced the sensitivity in 5-FU-sensitive cells. These results suggest that calpain might reduce the chemosensitivity of human gastric cancer cells to 5-FU possibly by rapid degradation of the TS-FdUMP complex, a finding that is considered to have novel therapeutic implications., (© 2011 Japanese Cancer Association.)

ONO 3403, a new synthetic serine protease inhibitor, is a derivative of camostat mesilate and has a higher protease-inhibitory activity. The effect of ONO 3403 on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α and nitric oxide (NO) production in RAW 264.7 macrophage-like cells was examined. ONO 3403 significantly inhibited LPS-induced TNF-α production at a lower concentration than camostat mesilate. It also inhibited LPS-induced NO production. Their inhibition was responsible for the reduced mRNA expression of TNF-α and inducible NO synthase. In LPS-stimulated cells, ONO 3403 prevented the augmentation of MyD88 expression and inhibited the phosphorylation of IκB-α, stress-activated protein kinase (SAPK) and IRF-3, and the production of interferon-β. ONO 3403 abolished the elevation of the extracellular serine protease activity in response to LPS. Further, it reduced the circulating TNF-α level, hepatic injury and mortality in mice receiving an injection of D-galactosamine and LPS. ONO 3403 was suggested to inhibit LPS-induced inflammatory responses via inactivation of MyD88-dependent and independent pathways.

We performed SEREX (serological identification of antigens by recombinant cDNA expression cloning) using the sera of patients with esophageal squamous cell carcinoma (SCC), and examined whether some of the SEREX antigens can affect chemosensitivity against anticancer drugs. We isolated a novel gene which was designated as AISEC (antigen identified by SEREX for esophageal carcinoma). RT-PCR analysis showed that the mRNA expression levels of AISEC were higher in esophageal SCC tissues than in their normal counterparts. By transfection into activated Ha-ras-transformed NIH3T3 (ras-NIH) mouse fibroblasts, we isolated a clone, FAISEC-3, which stably expressed AISEC. FAISEC-3 cells were more resistant to anticancer drugs, such as mitomycin C, ifosfamide, vincristine, camptothecin and etoposide, than parental ras-NIH cells. Luciferase reporter assay after a transient transfection with AISEC cDNA or the control vector revealed that the transactivity of p53 was suppressed by AISEC in a dose-dependent manner. These results suggested that esophageal SCC tissues produce AISEC in increased amounts, which can reduce the chemosensitivity against anticancer drugs possibly by suppressing the p53 transactivation ability.

Based on the genetic background of cancer, we have been trying to develop novel diagnostic and therapeutic strategies against human cancers. c-myc gene activation has been detected in many human cancers, indicating a key role of c-myc in tumor development. Thus targeting c-myc gene suppression is a promising strategy for cancer treatment. Recently, an interaction between FIR (FUSE-Binding Protein-Interacting Repressor) and TFIIH/p89/XPB helicase was found to repress c-myc transcription and so might be important for suppressing tumor formation. Previously, we have shown that the expression of splicing variant of FIR is elevated in colorectal cancer tissues and promotes tumor development by disabling FIR-repression to sustain high levels of c-Myc, opposing apoptosis in cancer cells. In this study, FIR recombinant adenovirus vector induces tumor growth suppression against tumor xenografts in animal model experiment. Together, one clue to the development of cancer diagnosis and therapies directed against c-Myc may go through FIR and its splicing variant.

Background: Serological identification of antigens by recombinant cDNA expression cloning (SEREX) is an established method for detecting new tumor-specific antigens. Antibodies to SEREX antigens may be useful for the detection of esophageal squamous cell carcinoma (SCC)., Methods: A phage cDNA library of a human esophageal SCC cell line was screened using sera of patients with esophageal SCC. The presence and levels of serum antibodies to SEREX antigens were established by Western blotting and enzyme-linked immunosorbent assay (ELISA) using purified recombinant antigen proteins, respectively., Results: The newly identified esophageal SCC antigen is encoded by a novel gene located on chromosome 1, here designated CUEC-23. Serum CUEC-23-antibodies (s-CUEC-23-Abs) were detected in 14 of 54 patients with esophageal SCC (26%) by Western blot analysis. Esophageal SCCs were positive for s-CUEC-23-Abs together with CEA, SCC-Ag or CYFRA21-1 in 44, 41 and 52% of cases, respectively. There was no detectable association between the presence of s-CUEC-23-Abs and clinicopathological variables. ELISA showed that the levels of s-CUEC-23-Abs were significantly higher in patients with esophageal SCC than in healthy volunteers (17% in the former using the mean+3 SD of s-CUEC-23-Abs in healthy controls as the cutoff)., Conclusion: A new tumor antigen, CUEC-23, was identified by SEREX screening. s-CUEC-23-Abs might be a useful serum marker to detect esophageal SCC.

There is an ongoing search for plant-derived diterpenes, especially for diterpenes with anti-inflammatory activity that also have anti-proliferative effects on human cancer cells. A cyathane-type diterpene, Sarcodonin G (SG), isolated from the mushroom Sarcodon scabrosus and already reported to have anti-inflammatory activity, inhibited proliferation of HeLa cells to the greatest extent among 4 cyathane diterpenes tested. SG showed an IC50 (50% inhibition concentration) of 20 microM, estimated by MTT assay 2 days after culture of cells with the chemical. SG treatment of HeLa cells resulted in dose-dependent generation of apoptotic events such as DNA-laddering (< or =100 microM). Moreover, SG-treated HeLa cells showed activation of caspase-3 and caspase-9 and increase of Bax/Bcl-2 ratios, as analyzed by Western blot analysis. The anti-proliferative effects of SG treatment on HeLa cells were lessened by a caspase inhibitor, Z-VAD-FMK. SG also showed anti-proliferative effects toward 5 other human cancer cell lines with IC50 values of 20-40 microM. Because of these anti-proliferative effects via possible caspase activation, SG holds promise of being a novel anti-proliferative agent deserving further investigation.

Background: No serum marker is currently available for the diagnosis and treatment of gliomas. Plasminogen activator inhibitor-1 (PAI-1) controls the proteolytic activity in cancer cells and cellular migration during angiogenesis., Patients and Methods: To verify the potential of PAI-1 as a serum marker for gliomas, the serum PAI-1 concentrations were measured by ELISA in 57 glioma patients and 34 healthy volunteers., Results: We found significantly higher serum levels in the patients with high-grade gliomas than in the healthy volunteers (p = 0.0009, unpaired t-test) and those with low-grade tumors (p = 0.0074). Furthermore, high-grade glioma patients with a low serum level of PAI-1 survived significantly longer than those with high levels (p = 0.0082). Immunohistochemical analysis using anti-PAI-1 antibody revealed dense and spotty staining in the high-grade tumor tissues from the patients with high serum PAI-1 levels., Conclusion: These results suggest that the serum PAI-1 level can be a marker for the prediction of histological grade in intracerebral glioma.

We previously performed SEREX (serological identification of antigens by recombinant expression cloning) using the sera of patients with esophageal squamous cell carcinoma (SCC), and isolated a variant clone (AK093616) of ubiquitin-conjugating enzyme E21 (UBE2I). This clone was tentatively designated as UBE2I-v5 and analyzed for biological function by transient transfection of the cDNA into activated Ha-ras-transformed NIH3T3 (ras-NIH) mouse fibroblasts. Chemosensitivity to 92 cytotoxic drugs was compared between UBE2I-v5-transfected cells and the parental ras-NIH cells. The UBE2I-v5-transfected cells were more sensitive than the parental cells to anticancer drugs such as vincristine (VCR), mitoxantrone (MIT) and etoposide (VP16). The regression analysis of the total chemosensitivity pattern of UBE2I-vS-transfected cells revealed that the function of UBE2I-v5 was positively related to RPA2 (replication protein A2), Rho-GDI (Rho guanine nucleotide dissociation inhibitor a), FUS (putative tumor suppressor) and TKT (transketolase) but negatively related to Per-1 (period-I), Ran (nuclear Ras-related protein), PTEN (phosphatase and tensin homolog), C/EBPalpha (CCAAT/enhancer binding protein a) and the tumor suppressor p53. Thus, it is possible that UBE21-v5 plays a role in carcinogenesis by suppressing the function of CIEBPa and/or p53 via RPA2-like activity.

Apoptotic cell death is frequently suppressed by NF-kappaB transcription factor. We examined the effects of NF-kappaB on the sensitivity to anti-cancer drugs by using two NF-kappaB-inhibitory molecules, IkappaBalpha-super-repressor (IkappaBalpha-SR) and dominant negative IKKbeta (IKKbeta-DN). Ha-ras-transformed NIH3T3 (ras-NIH3T3) mouse fibroblasts were stably transfected with these cDNAs, and suppression of NF-kappaB activity was confirmed by electrophoretic mobility shift assays. Cell viability analysis revealed that IkappaBalpha-SR- or IKKbeta-DN-transfected cells were more resistant to peplomycin, mitomycin C, and camptothecin. Flow cytometric analysis indicated partial G1 arrest of these transfected cells. Consistently, elevated expression of IkappaBalpha-SR and IKKbeta-DN was accompanied by increased levels of p21 but not of Bax. Transfection of p21 into ras-NIH3T3 cells caused similar reduced chemosensitivity to the anti-cancer drugs. These results collectively indicate that constitutive suppression of NF-kappaB activity reduced the chemosensitivity to anti-cancer drugs via enhanced expression of p21.

FOY-305 is a synthetic serine protease inhibitor and ONO-3403 is a derivative with a higher protease-inhibitory activity. The growth-suppressive effects of ONO-3403 were more prominent in Ha-ras-transformed NIH3T3 (ras-NIH) cells than in non-transformed NIH3T3 cells. After treatment of ras-NIH cells with ONO-3403 at 100-200 microg/ml, the percentage of cells found in G(1) phase decreased and, concomitantly, that in S phase increased. Molecular events caused by ONO-3403 were investigated by Western blot analysis using anti-phosphotyrosine antibody. The results showed a marked decrease in the tyrosine phosphorylation level of a 180-kDa protein after treatment with ONO-3403. This 180-kDa phosphotyrosine-containing molecule which was tentatively designated pY-p180 might be platelet-derived growth factor (PDGF) receptor since addition of PDGF to serum-starved NIH3T3 cells induced a marked tyrosine phosphorylation of the same size within 5 min. This was further confirmed by immunoprecipitation of cell extract with anti-PDGF-receptor antibody followed by Western blot analysis using anti-phosphotyrosine antibody. Treatment of T.Tn human esophageal carcinoma cells with ONO-3403 caused also decrease in pY-p180, which appeared to be epidermal growth factor receptor. Thus, ONO-3403 may induce growth suppression by down-regulation of cell surface growth factor receptors.

To investigate the effect of p33(ING1) on wild-type p53 gene therapy, T.Tn human esophageal carcinoma cells were stably transfected with p33(ING1) cDNA. Infection with Ad-p53 (recombinant adenovirus containing wild-type p53) into p33-transfected cells reduced cell viability, while infection with empty vector had little effect. This reduced viability was shown to be due to apoptotic cell death by the TUNEL (terminal deoxynucleotidyl transferase-mediated nick end-labeling) assay. Following infection with Ad-p53, levels of p53 were similar in p33-expressing cells and in the parental line. However, levels of p21 and Mdm2 were elevated in p33-transfected cells. Nonetheless, this enhanced expression of Mdm2 appeared to be ineffective in downregulating p53. Transient transfection with mutant Mdm2 prior to Ad-p53 infection provided a significant protection as compared with cells transfected with wild-type Mdm2. These results imply a synergistic effect between p33 and p53 in the induction of apoptosis of human esophageal carcinoma cells. A role for Mdm2 in this synergism is suggested.