Induction of nonspecific cross-reacting antigen mRNA by interferon-gamma and anti-fibronectin receptor antibody in colon cancer cells

Therapeutic effect of anti CEACAM6 monoclonal antibody against lung adenocarcinoma by enhancing anoikis sensitivity

Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) plays a crucial role in tumorigenesis of lung cancer. However, the therapeutic potential for anti CEACAM6 monoclonal antibody (mAb) has only been limitedly explored. Here, we evaluate the therapeutic potential of naked anti CEACAM6 mAb against lung adenocarcinoma. Clone 8F5, recognizing B domain of CEACAM6, is established by immunizing A549 cells and screening for clones double positive for A549 and CEACAM6-Fc recombinant protein. We found that 85.7% of 70 resected lung adenocarcinoma tissue sections were positive for CEACAM6, whereas all squamous cell carcinoma examined were negative. A549 cells with high levels of CEACAM6 demonstrated more aggressive growth nature and showed increased paclitaxel chemosensitivity upon 8F5 binding. Treatment with 8F5 to A549 decreased cellular CEACAM6 expression and reversed anoikis resistance. 8F5 also decreased cellular status of Akt phosphorylation and increased apoptosis via caspase activation. In a mouse model of lung adenocarcinoma with xenotransplanted A549 cells, 8F5 treatment alone demonstrated 40% tumor growth inhibition. When combined with paclitaxel treatment, 8F5 markedly enhanced tumor growth inhibition, up to 80%. In summary, we demonstrate that anti CEACAM6 mAb is an effective therapeutic treatment for lung adenocarcinoma whose effect is further enhanced by combined treatment with paclitaxel.

Recombinant Salmonella-based CEACAM6 and 4-1BBL vaccine enhances T-cell immunity and inhibits the development of colorectal cancer in rats: In vivo effects of vaccine containing 4-1BBL and CEACAM6

The present study aimed to determine the effect of recombinant Salmonella (SL3261)-based CEACAM6 and 4-1BB ligand (4-1BBL) vaccine on the development of colorectal cancer in rats and the potential immune mechanisms involved. Attenuated Salmonella typhimurium (vaccine strain)‑carrying plasmids pIRES-CEACAM6, pIRES‑4‑1BBL and pIRES-CEACAM6-4-1BBL were constructed. The rats were administered subcutaneous injections of 1,2-dimethyl-hydrazine (DMH) once a week for 18 weeks. Eight weeks after the first injection, the rats were divided into the pIRES/SL3261, pIRES-4-1BBL/SL3261, pIRES-CEACAM6/SL3261 and pIRES-CEACAM6-4-1BBL/SL3261 groups, and fed with corresponding vaccine strains. The rats were then sacrificed, the number of colon tumors were recorded, and the Dukes' stage were evaluated. CD3, CD4, CD8, CD56, FOXP3 and CEACAM6 expression in tumor tissues was determined by immunohistochemical staining. Compared with the expression levels in the pIRES/SL3261 group, similar levels of CD3+, CD8+ and CD56+ expression were identified for the pIRES-CEACAM6/SL3261 group of rats. Additionally, a comparable number of tumors was detected in the pIRES-4-1BBL/SL3261 and pIRES-CEACAM6/SL3261 groups. By contrast, a significantly fewer number of tumors, albeit with a higher density of CD3+CD8+, CD56+ and a lower density of Foxp3+ tumor-infiltrating lymphocyte (TIL) cells was detected in the pIRES-CEACAM6-4-1BBL/SL3261 group of rats. The results indicated that vaccination with recombinant attenuated Salmonella harboring the CEACAM6 and 4-1BBL gene efficiently increased the number of CD3+CD8+ TIL and NK cells, decreased the number of FOXP3 cells and inhibited the development of DMH-induced colorectal cancer in rats.

CEACAM6 as detected by the AP11 antibody is a marker notable for mucin-producing adenocarcinomas

A new monoclonal antibody recognizing CEACAM6, which we named AP11, was generated by immunizing BALB/c mice with phytohemagglutinin-activated human peripheral blood mononuclear cells. This study aims to evaluate whether CEACAM6 can serve as a tumor marker using AP11. We examined the expression of CEACAM6 with AP11 in 11 human carcinoma cell lines by flow cytometry and 439 human tissues including 282 tumor tissues and 157 normal tissues by immunohistochemistry. CEACAM6 epitope recognized by AP11 was well preserved in formalin-fixed and paraffin-embedded tissues. Adenocarcinomas of the stomach (86 %), colorectum (95 %), pancreas (100 %), and lung (83 %), urinary bladder (100 %), and mucinous ovarian tumors (88 %) had a high rate of CEACAM6 immunoreactivity. We observed a variable expression of CEACAM6 in hepatocellular carcinomas (35 %), squamous cell carcinomas of the lung (60 %), renal cell carcinomas (14 %), urothelial carcinomas (13 %), serous carcinomas of the ovary (17 %), and breast carcinomas (11 %). Small-cell carcinomas of the lung, prostatic adenocarcinomas, papillary thyroid carcinomas, malignant melanomas, giant cell tumors, and osteosarcomas were negative for CEACAM6. All normal tissues of various organs were negative for CEACAM6. In conclusion, CEACAM6 as detected by AP11, may serve as a marker for mucin-producing adenocarcinomas of the gastrointestinal tract and ovary as well as non-small cell lung cancer. Thus, AP11 represents a valuable diagnostic tool for detecting CEACMA6-positive cancers.

Identification of glycoproteins associated with different histological subtypes of ovarian tumors using quantitative glycoproteomics

Ovarian cancer is the most lethal gynecologic malignancy in adult women. The origin of epithelial ovarian tumors is both morphologically and biologically heterogeneous, and different subtypes of ovarian tumors have different clinical outcomes. In spite of the heterogeneous nature of ovarian carcinoma, the current biomarkers and treatments for this disease are not subtype-specific. To discover the molecular basis of the ovarian tumor subtypes, we analyzed extracellular glycoproteins of seven common subtypes and normal ovary tissues using quantitative glycoproteomic analysis. Glycoproteins for different ovarian tumor subtypes were identified by liquid chromatography-tandem mass spectrometry and quantitated by spectral counting and then verified by iTRAQ labeling and Western blotting. Glycoproteins uniquely expressed in different subtypes of ovarian tumors or commonly expressed in most subtypes were identified. Using Western blots, we verified that mesothelin was overexpressed in serous carcinoma and transitional-cell carcinoma, CEA5 and CEA6 were overexpressed only in mucinous carcinoma, while versican and periostin were overexpressed in most subtypes of ovarian tumors. This study presents the first proteomic characterization of different ovarian tumor subtypes. The identified glycoproteins for histological subtypes of ovarian tumors will facilitate the understanding of the molecular basis, diagnosis of ovarian tumor subtypes, and predictions for treatment responses to therapeutic agents.

Expression patterns of CEACAM5 and CEACAM6 in primary and metastatic cancers

BACKGROUND

Many breast, pancreatic, colonic and non-small-cell lung carcinoma lines express CEACAM6 (NCA-90) and CEACAM5 (carcinoembryonic antigen, CEA), and antibodies to both can affect tumor cell growth in vitro and in vivo. Here, we compare both antigens as a function of histological phenotype in breast, pancreatic, lung, ovarian, and prostatic cancers, including patient-matched normal, primary tumor, and metastatic breast and colonic cancer specimens.

METHODS

Antigen expression was determined by immunohistochemistry (IHC) using tissue microarrays with MN-15 and MN-3 antibodies targeting the A1B1- and N-domains of CEACAM6, respectively, and the MN-14 antibody targeting the A3B3 domain of CEACAM5. IHC was performed using avidin-biotin-diaminobenzide staining. The average score +/- SD (0 = negative/8 = highest) for each histotype was recorded.

RESULTS

For all tumors, the amount of CEACAM6 expressed was greater than that of CEACAM5, and reflected tumor histotype. In breast tumors, CEACAM6 was highest in papillary > infiltrating ductal > lobular > phyllodes; in pancreatic tumors, moderately-differentiated > well-differentiated > poorly-differentiated tumors; mucinous ovarian adenocarcinomas had almost 3-fold more CEACAM6 than serous ovarian adenocarcinomas; lung adenocarcinomas > squamous tumors; and liver metastases of colonic carcinoma > primary tumors = lymph nodes metastases > normal intestine. However, CEACAM6 expression was similar in prostate cancer and normal tissues. The amount of CEACAM6 in metastatic colon tumors found in liver was higher than in many primary colon tumors. In contrast, CEACAM6 immunostaining of lymph node metastases from breast, colon, or lung tumors was similar to the primary tumor.

CONCLUSION

CEACAM6 expression is elevated in many solid tumors, but variable as a function of histotype. Based on previous work demonstrating a role for CEACAM6 in tumor cell migration, invasion and adhesion, and formation of distant metastases (Blumenthal et al., Cancer Res 65: 8809-8817, 2005), it may be a promising target for antibody-based therapy.

Inhibition of adhesion, invasion, and metastasis by antibodies targeting CEACAM6 (NCA-90) and CEACAM5 (Carcinoembryonic Antigen)

CEACAM5 and CEACAM6 are overexpressed in many cancers and are associated with adhesion and invasion. The effects of three monoclonal antibodies targeting different epitopes on these antigens (NH2-terminal [MN-3] and A1B1 domains [MN-15] shared by CEACAM5 and CEACAM6 and the A3B3 domain [MN-14] restricted to CEACAM5) were evaluated in migration, invasion, and adhesion assays in vitro using a panel of human pancreatic, breast, and colonic cancer cell lines, and in the GW-39 human colonic micrometastasis model in vivo. MN-3 Fab' and MN-15 Fab' were both effective at inhibiting cell migration. MN-15 Fab' treatment inhibited invasion, reducing cell penetration through an extracellular matrix (ECM). MN-3 Fab' also decreased invasion but was less effective than MN-15 Fab' in four of five cell lines. All three monoclonal antibody (mAb) Fabs decreased adhesion of tumor cells to endothelial cells by 49% to 58%. MN-15 Fab' but not MN-3 or MN-14 Fabs induced a decrease in adhesion of three of six cell lines to the ECM protein, fibronectin, but adhesion to vitronectin, laminin, collagen-I, and collagen-IV was not affected. In vivo studies showed that treatment with MN-3 Fab' or MN-15 Fab' of mice implanted with GW-39 human colonic cancer cells increased their survival (P < 0.025 and P < 0.01, respectively). These studies show that antibody Fabs that target either CEACAM5 or CEACAM6 affect cell migration, cell invasion, and cell adhesion in vitro, and that MN-15 and MN-3 Fabs have antimetastatic effects in vivo, resulting in improved survival of mice with metastases. Thus, blocking the N and A1B1 domains of CEACAM5/CEACAM6 can impede the metastatic process.

Phosphodiesterase type III inhibitor, cilostazol, inhibits colon cancer cell motility

Metastasis of cancer cells is initiated by the cellular migration into extracellular matrix and surrounding vessels. We previously showed that elevation of cAMP levels in cancer cells suppressed trans-cellular migration in vitro. Drugs that can elevate cAMP levels in cancer cells effectively may be applied to prevent metastasis in cancer patients. Cilostazol, an oral anti-platelet drug, is a specific cAMP phosphodiesterase type III inhibitor and has been clinically used to treat thrombosis patients. In chemotaxis assay, cellular migration of human colon cancer cells, DLD- 1, was induced by 10 microg/ml of soluble fibronectin or 10% of fetal bovine serum (FBS). Treatment with cilostazol (50 microM) suppressed 92.3% or 84.6% of the migration in control cells, respectively. When DLD-1 cells were stimulated by soluble fibronectin in phagokinetic assay, migration assessed by the area of gold particle phagocytosis track was induced and cilostazol also decreased 67.3% of the cellular migration in control cells. Furthermore, in the trans-cellular migration assay, cilostazol suppressed cancer cell invasion induced by FBS. Thus, cilostazol can suppress colon cancer cell motility and might be effective as an anti-metastasis drug for cancer patients.