Essential Amino Acid Starvation-Induced Oxidative Stress Causes DNA Damage and Apoptosis in Murine Osteoblast-like Cells.

Intracellular nutrient metabolism, particularly the metabolism of essential amino acids (EAAs), is crucial for cellular functions, including energy production and redox homeostasis. An EAA deficiency can lead to cellular dysfunction and oxidative stress. This study explores the mechanisms underlying cellular responses to EAA starvation, focusing on ROS-induced DNA damage and apoptosis. MC3T3-E1 cells were subjected to EAA starvation, and various assays were conducted to assess cell proliferation, survival, DNA damage, and apoptosis. The antioxidant N-acetylcysteine (NAC) was employed to block ROS formation and mitigate cellular damage. Gene expression and Western blot analyses were performed to elucidate molecular pathways. EAA starvation-induced ROS generation, DNA damage, and apoptosis in MC3T3-E1 cells. NAC administration effectively reduced DNA damage and apoptosis, highlighting the pivotal role of ROS in mediating these cellular responses during EAA deficiency. This study demonstrates that EAA starvation triggers ROS-mediated DNA damage and apoptosis, offering insights into the intricate interplay between nutrient deficiency, oxidative stress, and programmed cell death. NAC emerges as a potential therapeutic intervention to counteract these adverse effects.

Prognostic value of CEA and CK20 mRNA in the peritoneal lavage fluid of patients undergoing curative surgery for gastric cancer.

BACKGROUND: Peritoneal recurrence is the most common type of recurrence in gastric cancer. Although cytological examination of peritoneal lavage fluid has been used to predict peritoneal spread, peritoneal recurrences often occur even in patients with negative cytology. Our previous retrospective study suggested that reverse transcriptase-polymerase chain reaction (RT-PCR) using peritoneal lavage fluid may be useful for predicting peritoneal recurrence in patients with negative cytology. This prospective study was conducted to validate the clinical impact of this RT-PCR method. METHODS: From July 2009 to June 2012, a total of 118 cT2-4 gastric cancer patients underwent surgery. Since 14 patients were ineligible because they had incurable factors, the remaining 104 eligible patients were evaluated for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) messenger RNA (mRNA) using RT-PCR. If either CEA or CK20 mRNA was detected by RT-PCR, the patient was defined as PCR-positive as in our previous study. The association between recurrence-free survival (RFS) and background factors was analyzed using Cox proportional hazards models. RESULTS: Of 104 patients, 16 (15.4 %) were positive for either CEA or CK20. PCR-positive patients had significantly worse RFS than PCR-negative patients (log-rank p = 0.007). Regarding the pattern of recurrence, 4 of 16 (25 %) PCR-positive patients and 2 of 88 (2 %) PCR-negative patients had peritoneal recurrence (p < 0.001), but there were no significant differences in recurrence at other sites. Cox multivariate analysis indicated only PCR-positivity as a significant predictor of poor RFS (p = 0.029). CONCLUSION: This prospective study demonstrated that CEA and CK20 PCR results could predict peritoneal recurrence after curative surgery.

Overexpression of forkhead box M1 transcription factor (FOXM1) is a potential prognostic marker and enhances chemoresistance for docetaxel in gastric cancer.

BACKGROUND: Mammalian forkhead box transcription factor 1 (FoxM1) has been overexpressed and correlated with pathogenesis in a variety of human malignancies. We investigated the expression status and clinical significance of its overexpression in gastric adenocarcinoma. Furthermore, we demonstrated correlations between FoxM1 overexpression and drug resistance to chemotherapeutic agents in gastric cancer cells and gastric cancer patients treated with chemotherapy. METHODS: Fifty-three (69%) of 77 tumors were diagnosed as positive for FoxM1 by immunohistochemistry. Multivariate analysis identified FoxM1 expression as a significant independent prognostic predictor for overall and disease-free survival in gastric cancer patients (hazard ratio 3.9 and 3.5, respectively). Furthermore, we investigated associations between FoxM1 overexpression and clinical response of chemotherapy for patients with advanced gastric cancer. RESULTS: Our clinical results showed that FoxM1 overexpression was significantly associated with resistance in chemotherapy of docetaxel in addition to 5-fluorouracil (5-FU) plus S-1 plus cisplatin (CDDP) and was not significant in chemotherapy of 5-FU plus CDDP for patients with advanced gastric cancer. In vitro experiments showed that Mkn7 transfected FoxM1 siRNA significantly reduced chemoresistance to docetaxel over that with parental cell lines and Mkn45 transfected with FoxM1 significantly enhanced chemoresistance to docetaxel over that with parental cell lines. CONCLUSIONS: Our study showed that FoxM1 was an independent prognostic factor in gastric cancer. Furthermore, we showed that FoxM1 was a critical molecule for chemoresistance to a microtubule-stabilizing anticancer agent, docetaxel. Taken together, those results suggest that inhibition of overexpressed FoxM1 will be a promising therapeutic strategy for advanced gastric cancer.

Heteroclitic serological response in esophageal and prostate cancer patients after NY-ESO-1 protein vaccination.

NY-ESO-1 is a prototypic cancer/testis antigen. In a recent phase I clinical trial, we vaccinated 13 patients bearing NY-ESO-1-expressing tumors with a complex of cholesterol-bearing hydrophobized pullulan (CHP) and NY-ESO-1 protein (CHP-NY-ESO-1) and showed efficient induction of NY-ESO-1 antibody, and CD4 and CD8 T cell responses using peripheral blood from the patients. In our study, we analyzed heteroclitic serological responses in those patients after vaccination. Serological response against 11 tumor antigens including MAGE-A1, MAGE-A3, MAGE-A4, CT7/MAGEC1, CT10/MAGEC2, CT45, CT46/HORMAD1, SOX2, SSX2, XAGE1B and p53 was examined by enzyme-linked immunosorbent assay (ELISA) using sera from ten vaccinated patients. Expression of tumor antigens was determined by reverse transcription-polymerase chain reaction or immunohistochemistry. Eight of nine patients who showed antibody responses against NY-ESO-1 also showed an antibody response against at least 1 of these 11 tumor antigens after vaccination. In one patient, seven tumor antigens were recognized. Specificity analysis of the antibody response by ELISA using control recombinant proteins and synthetic peptides and by Western blot showed that the response was not against His6-tag and/or bacterial products included in a preparation of CHP-NY-ESO-1 used for vaccination. Thus, heteroclitic serological responses appear to be indicative of the overall immune response against the tumor, and their analysis could be useful for immune monitoring in cancer vaccine.

Oncofetal protein, IMP-3, a potential marker for prediction of postoperative peritoneal dissemination in gastric adenocarcinoma.

BACKGROUND: The aim of this study was to determine the expression of insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP-3) and its clinical significance in gastric cancers, as well the prognostic value of its expression in the peritoneal lavage fluid after surgery. METHODS: IMP-3 expression was examined by immunohistochemistry in 96 primary gastric tumors. IMP-3 mRNA expression in peritoneal lavage fluid obtained at laparotomy was determine by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Positive staining for IMP-3 was observed in 74% (71/96) of the tumors. IMP-3 expression in gastric tumors correlated significantly with worst overall survival (OS) and recurrence-free survival. Multivariate analyses identified pathological N stage and IMP-3 expression as significant independent prognostic factors for disease-free survival. Eight (28%) of 36 peritoneal lavage samples were cytologically negative but positive for IMP-3 mRNA expression by RT-PCR. The OS of patients with IMP-3-positive peritoneal lavage was significantly worse than of those with negative expression. CONCLUSIONS: IMP-3 expression in primary gastric tumors was an independent poor prognostic factor. IMP-3 mRNA expression in peritoneal lavage fluid was a predictor of recurrence after surgery in gastric cancer and a marker of poor prognosis.

REGIV as a potential biomarker for peritoneal dissemination in gastric adenocarcinoma.

BACKGROUND: This study examined the clinical significance of regenerating islet-derived family member 4 (REGIV) in surgically resected gastric tumors. The potential of REGIV as a biomarker in gastric cancer was also assessed including its predictive value for prognosis and recurrence after surgery. METHODS: Immunohistochemistry was performed to assess the clinical significance of REGIV expression status in surgically resected specimens. The quantitative genetic diagnostic method, transcription-reverse transcription concerted reaction (TRC) that targeted REGIV mRNA was applied for prediction of peritoneal recurrence in gastric cancer. RESULTS: Positive immunostaining for REGIV was observed in 85 cases (52.5%), and correlated significantly with diffuse type histopathology (P = 0.001), advanced T stage (P = 0.022), and frequent peritoneal recurrence (P = 0.009). Multivariate analysis identified advanced T stage (P < 0.001) and REGIV expression (P = 0.034) as independent prognostic factors for peritoneal recurrence-free survival. Overexpression of REGIV protein was evident in the majority of peritoneal tumors (93.8%). REGIV mRNA assessed by TRC could be a predictive marker for peritoneal recurrence after curative operation. CONCLUSIONS: REGIV overexpression is common in primary gastric tumors and a potentially suitable marker of diffuse type histopathology and peritoneal dissemination. Overexpression of REGIV mRNA, assessed by the TRC method, is a potentially suitable marker of peritoneal recurrence after curative resection.

Identification of CCDC62-2 as a novel cancer/testis antigen and its immunogenicity.

Cancer/testis (CT) antigens are expressed in normal germ line tissues and various cancers. They are considered promising target molecules for immunotherapy for patients with various cancers. To identify CT antigens, we performed serological identification of antigens by recombinant expression cloning. The humoral immune response of cancer patients against a newly defined antigen was analyzed. A testicular cDNA library was immunoscreened with serum obtained from a gastric adenocarcinoma patient whose primary cancer had regressed once and most liver metastases had disappeared transiently. We isolated 55 positive cDNA clones comprising 23 different genes. They included 4 genes with testis-specific expression profiles in the Unigene database, including coiled-coil domain containing 62 (CCDC62). RT-PCR analysis showed that the expression of 2 splice variants of CCDC62 was restricted to the testis in normal adult tissues. In malignant tissues, CCDC62 variant 2 (CCDC62-2) was aberrantly expressed in a variety of cancers, including stomach cancer. A serological survey of 191 cancer patients with a range of different cancers by ELISA revealed antibodies to CCDC62-2 in 13 patients, including stomach cancer. None of the 41 healthy donor serum samples were reactive in the same test. The serum reaction against CCDC62-2 was confirmed by western blot. CCDC62-2 is a CT antigen that is immunogenic in cancer patients.

Dickkopf-1 expression as a marker for predicting clinical outcome in esophageal squamous cell carcinoma.

BACKGROUND AND OBJECTIVES: Dickkopf-1 (DKK1) is the inhibitor of the canonical Wnt signaling pathway, however it is highly transactivated in various cancers, suggesting the presence of unknown mechanism. Its implication in human esophageal squamous cell carcinoma (ESCC) has not been sufficiently investigated. PATIENTS AND METHODS: We evaluated DKK1 protein expression in resected specimens from 170 patients with ESCC by immunohistochemistry. Tumors were categorized as positive or negative for DKK1. The relationships between DKK1 expression in ESCC and various clinicopathological parameters and prognosis (disease-free survival; DFS) were analyzed separately. RESULTS: Immunohistochemically, 72 (42.4%) tumors were DKK1 positive while no significant staining was observed in the normal squamous epithelium except for few basal cells. There was no significant relationship between DKK1 expression in ESCC and any of the clinicopathological parameters tested in this study. Patients with DKK1-positive tumors had poorer DFS than those with negative ESCC (5-year DFS; 31.5% versus 53.6%, P = 0.0062). Univariate analysis showed a significant relationship between pT [hazard ratio (HR) = 2.944, 95% confidence interval (CI) = 1.713-5.059, P < 0.0001], number of pN (HR = 2.836, 95% CI = 1.866-4.309, P < 0.0001), lymphatic invasion (HR = 2.892, 95% CI = 1.336-6.262, P = 0.0070), and DKK1 expression (HR = 1.763, 95% CI = 1.167-2.663, P = 0.0071) and DFS. Multivariate analysis including the above four parameters identified pT (HR = 2.053, 95% CI = 1.157-3.645, P = 0.0140), pN number (HR = 2.107, 95% CI = 1.362-3.260, P = 0.0008), and DKK1 expression (HR = 1.813, 95% CI = 1.195-2.751, P = 0.0052) as independent and significant prognostic factors for DFS. CONCLUSION: Our data suggest the usefulness of DKK1 as a novel predictor of poor prognosis of patients with ESCC after curative resection and also as a therapeutic target for future tailored therapies against ESCC.

Aberrant expression of connexin 26 is associated with lung metastasis of colorectal cancer.

PURPOSE: Connexin 26 (Cx26) is one of the gap junction-forming family members classically considered to be tumor suppressors. However, recent studies show association of elevated expression of Cx26 with poor prognosis in several human malignancies. Furthermore, Cx26 has been observed to be indispensable to spontaneous metastasis of melanoma cells. Here, we assessed Cx26 expression in primary colorectal cancer (CRC) and the metastatic lesions to elucidate its role in metastasis. EXPERIMENTAL DESIGN: Cx26 expression was assessed in 25 adenomas, 167 CRCs, and normal mucosa, together with the metastatic lesions. RESULTS: Normal mucosa and adenomatous tissue expressed Cx26 mainly in the plasma membrane, whereas cancer cells mostly contained Cx26 in the cytoplasm. The incidence of aberrant Cx26 expression varied widely in CRC (mean, 49.5 +/- 35.5%), and the expression levels were confirmed by Western blot and quantitative reverse transcription-PCR. Clinicopathologic survey revealed association of high expression with less differentiated histology and venous invasion (P = 0.0053 and P = 0.0084, respectively). Notably, high Cx26 expression was associated with shorter disease-free survival and shorter lung metastasis-free survival in 154 curatively resected CRC sets (P = 0.041 and P = 0.028, respectively). Survey of metastatic lesions revealed that lung metastasis, but not liver and lymph nodes metastases, expressed higher Cx26 than the CRC series or corresponding primary CRCs (P < 0.0001 and P = 0.0001, respectively). CONCLUSIONS: These findings suggest that aberrant expression of Cx26 plays an essential role in lung metastasis. Thus, Cx26 is a promising therapeutic target, particularly for CRC patients who develop lung metastasis.

Analysis of peripheral and local anti-tumor immune response in esophageal cancer patients after NY-ESO-1 protein vaccination.

NY-ESO-1 antigen is a prototype of a class of cancer/testis antigens. We carried out a clinical trial using NY-ESO-1 whole protein as a cancer vaccine for 13 advanced cancer patients. We have recently reported that vaccine elicited humoral and cellular immune responses in 9 cancer patients including 4 esophageal cancer patients, and clinical responses were also observed in 4 of 5 evaluable patients. In this study, we analyzed the responses in 8 esophageal cancer patients including 4 newly enrolled patients. Patients were injected subcutaneously at biweekly intervals with NY-ESO-1 recombinant protein formulated with cholesterol-bearing hydrophobized pullulan. Induction of antibody, and CD4 and CD8 T-cell responses were observed in 7, 7 and 6 patients, respectively, out of 8 patients. 1 PR, 2 SD and 2 mixed clinical responses were observed in 6 evaluable patients. No significant adverse events were observed. Furthermore, we analyzed NY-ESO-1 and MHC class I expression and the infiltration of immune cells into tumor samples obtained before and after vaccination from 4 patients by immunohistochemistry. The results showed 2 patients with disappearance of CD4 and CD8 T-cell infiltration, 1 patient with increase in the number of CD68(+) macrophages and 1 patient with tumor antigen loss in the progressive tumors following vaccinations. The induction of NY-ESO-1 immunity and some preferable clinical outcomes were observed in esophageal cancer patients by vaccination with NY-ESO-1. However, the tumors grew eventually by various mechanisms after vaccination.

Identification of the HERV-K gag antigen in prostate cancer by SEREX using autologous patient serum and its immunogenicity.

The prostate cancer HERV-K gag-related NGO-Pr-54 antigen was identified by SEREX analysis using autologous patient serum. NGO-Pr-54 mRNA was observed to be faintly expressed in normal prostate and strongly expressed in a variety of cancers, including ovarian cancer (5/8), prostate cancer (6/9), and leukemia (5/14). A phage plaque assay showed that a strong reaction was constantly observed with clone ZH042 in which the 5' end of NGO-Pr-54 is deleted, suggesting that it contained the sequence coding for the protein product. A TI-35 mAb was produced using a recombinant protein (438 aa) deduced from the sequence of ZH042. Transfection of clone ZH042 into 293T cells resulted in the production of an approximately 50-kDa molecule visualized by Western blotting. Natural production of the molecule was confirmed in a SK-MEL-23 melanoma cell line. An indirect immunofluorescence assay showed that NGO-Pr-54 protein was expressed on the cell surface as well as in the cytoplasm. Cell surface expression was confirmed by flow cytometry using the TI-35 mAb. The antibody response against NGO-Pr-54 was observed in patients with bladder (5.1%), liver (4.1%), lung (3.4%), ovarian (5.6%), and prostate (4.2%) cancer, as well as with malignant melanoma (13.2%).

[Peritoneal lavage diagnosis with TRC (transcription reverse transcription concerted reaction) system for prediction of peritoneal recurrence in gastric cancer].

Peritoneal dissemination is the most frequent recurrent type in advanced gastric cancer. Therefore, the early detection or prediction of peritoneal dissemination is important for the management of patients with advanced gastric cancer. Cytological examination with peritoneal lavage fluids obtained at surgery is widely used for the detection of peritoneal dissemination in gastric cancer. However, the sensitivity of the conventional method is not enough for the prediction of peritoneal recurrence. Recently, molecular diagnosis for detection of cancer cells has been widely studied as the sensitive method for detection of cancer micrometastasis in patients with malignancies including gastric cancer. In this study, novel genetic diagnosis with TRC (transcription reverse transcription concerted reaction) system for detection of carcinoembryonic antigen (CEA) mRNA (Tosoh corporation, Tokyo, Japan) has been introduced for peritoneal lavage diagnosis. We assessed the sensitivity and reproducibility of the test using the diluted gastric cancer cells. Furthermore, the results of TRC with peritoneal lavage fluids obtained from gastric cancer patients has been compared with results of conventional cytology and RT-PCR (reverse transcriptase-polymerase chain reaction).

Micrometastasis Volume in Lymph Nodes Determines Disease Recurrence Rate of Stage II Colorectal Cancer: A Prospective Multicenter Trial.

PURPOSE: We reported in a retrospective study that the presence of micrometastasis in lymph nodes, when assessed by carcinoembryonic antigen (CEA)-specific RT-PCR, is a significant prognostic factor in stage II colorectal cancer. The aim of this study was to clarify the clinical value of micrometastasis in a prospective multicenter trial. EXPERIMENTAL DESIGN: From November 2001 to December 2005, a total of 419 colorectal cancer cases were preoperatively registered at a central data center. Of them, 315 node-negative stage II colorectal cancer cases were enrolled. After RNA quality check, 304 colorectal cancer cases were analyzed for CEA mRNA in lymph nodes by both conventional RT-PCR (a band method) and quantitative RT-PCR. Long-term prognosis of the patients was determined by each method. RESULTS: A positive band for CEA mRNA was detected in 73 (24.0%) of 304 patients. Postoperative adjuvant chemotherapy was applied in 31 CEA band-positive cases with an oral 5-fluorouracil derivative HCFU (1-hexylcarbamoyl-5-fluorouracil) for 1 year, whereas chemotherapy was not administered to CEA band-negative group. Multivariate Cox regression analyses revealed that a high micrometastasis volume (high MMV, n = 95) was an independent poor prognostic factor for 5-year disease-free survival (DFS; P = 0.001) and 5-year overall survival (OS; P = 0.016). CONCLUSIONS: This prospective clinical trial demonstrates that micrometastasis volume is a useful marker in identifying patients who are at high or low risk for recurrence of stage II colorectal cancer. Clin Cancer Res; 22(13); 3201-8. ©2016 AACR.

Clinical trial of the intratumoral administration of labeled DC combined with systemic chemotherapy for esophageal cancer.

Esophageal cancer is a highly aggressive disease, and improved modalities for its treatment are needed. We performed chemoimmunotherapy involving the intratumoral administration of 111In-labeled dendritic cells (DC) in combination with preoperative chemotherapy in 5 esophageal cancer patients. Mature DC were generated and traced by scintigraphy after their administration. No adverse events that were directly related to the intratumoral DC administration were observed. Delayed-type hypersensitivity skin tests against keyhole limpet hemocyanin, which was added to the culture medium, detected a positive response in 3 patients, and keyhole limpet hemocyanin antibody production was observed in 4 patients, suggesting that intratumorally administered DC migrate to the lymph nodes, where they function as antigen-presenting cells. However, scintigraphic images obtained after the DC administration demonstrated that the DC remained at the esophageal tumor injection sites in all cases, and no DC accumulation was observed elsewhere. The accumulation of CD83+ cells in the primary tumor was also observed in 2 out of 4 patients in an immunohistochemical analysis using surgically resected specimens. Although the induction of tumor-specific immune responses during chemoimmunotherapy was also analyzed in enzyme-linked immunosorbent assay against 28 tumor antigens, none of the antibodies against the antigens displayed enhanced titers. No changes of NY-ESO-1-specific cellular immune response was observed in a patient who displayed NY-ESO-1 antibody production before the DC administration. These results suggest that the intratumoral administration of 111In-labeled mature DC during chemotherapy does not lead to detectable DC migration from the primary tumor to the draining lymph nodes, and therefore, might not achieve an optimal clinical response.