Tumor suppressor carcinoembryonic antigen-related cell adhesion molecule 1 potentates the anchorage-independent growth of human hepatoma HepG2 cells

Switch receptor T3/28 improves long-term persistence and antitumor efficacy of CAR-T cells

Background

Chimeric antigen receptor (CAR) T cells have been successfully used in tumor immunotherapy due to their strong antitumor responses, especially in hematological malignancies such as B cell acute lymphoid leukemia. However, on-target off-tumor toxicity and poor persistence severely limit the clinical application of CAR-T cell therapy.

Methods

T-cell immunoglobulin mucin domain molecule 3 (TIM-3) was used to develop a second-generation 41BB CD19 CAR linked with a T3/28 chimera, in which truncated extracellular TIM-3 was fused with the CD28 transmembrane and cytoplasmic domains. The efficacy of T3/28 CAR-T cells was evaluated in vitro and in vivo.

Results

We demonstrated that the switch receptor T3/28 preserved the T_CM phenotype, improved proliferative capacity, and reduced exhaustion of CAR-T cells, resulting in superior in vitro and in vivo antitumor activity in B lymphoma. Importantly, the switch receptor T3/28 substantially prolonged the persistence of CAR-T cells, and the interleukin-21/Stat3 axis probably contributed to the enhanced cytotoxicity of T3/28 CAR-T cells.

Conclusion

Overall, the T3/28 chimera significantly prolonged the persistence of CAR-T cells, and T3/28 CAR-T cells possessed potent antitumor activity in mice, shedding new light on potential improvements in adoptive T cell therapies.

Human CEACAM1-LF regulates lipid storage in HepG2 cells via fatty acid transporter CD36

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed in the liver and secreted as biliary glycoprotein 1 (BGP1) via bile canaliculi (BCs). CEACAM1-LF is a 72 amino acid cytoplasmic domain mRNA splice isoform with two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Ceacam1^−/− or Ser503Ala transgenic mice have been shown to develop insulin resistance and nonalcoholic fatty liver disease; however, the role of the human equivalent residue, Ser508, in lipid dysregulation is unknown. Human HepG2 hepatocytes that express CEACAM1 and form BC in vitro were compared with CEACAM1^−/− cells and CEACAM1^−/− cells expressing Ser508Ala null or Ser508Asp phosphorylation mimic mutations or to phosphorylation null mutations in the tyrosine ITIMs known to be phosphorylated by the tyrosine kinase Src. CEACAM1^−/− cells and the Ser508Asp and Tyr520Phe mutants strongly retained lipids, while Ser508Ala and Tyr493Phe mutants had low lipid levels compared with wild-type cells, indicating that the ITIM mutants phenocopied the Ser508 mutants. We found that the fatty acid transporter CD36 was upregulated in the S508A mutant, coexpressed in BCs with CEACAM1, co-IPed with CEACAM1 and Src, and when downregulated via RNAi, an increase in lipid droplet content was observed. Nuclear translocation of CD36 associated kinase LKB1 was increased sevenfold in the S508A mutant versus CEACAM1^−/− cells and correlated with increased activation of CD36-associated kinase AMPK in CEACAM1^−/− cells. Thus, while CEACAM1^−/− HepG2 cells upregulate lipid storage similar to Ceacam1^−/− in murine liver, the null mutation Ser508Ala led to decreased lipid storage, emphasizing evolutionary changes between the CEACAM1 genes in mouse and humans.

Cell-dependent regulation of vasculogenic mimicry by carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1)

Vasculogenic mimicry (VM) promotes tumor migration, metastasis, and invasion in various types of cancer, but the relationship between VM and these phenotypes remains undefined. In this study, we examined carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) as a novel target of VM. We found that ectopic expression of CEACAM1 in HT1080 human fibrosarcoma cells suppressed the formation of a VM-like network. Further, cell migration and proliferation were abated by the introduction of CEACAM1 into HT1080 cells. Conversely, knockout (KO) of the CEACAM1 gene in SK-MEL-28 melanoma cells, which normally express high levels of CEACAM1, inhibited formation of a VM-like network, which was covered on reintroduction of CEACAM1. These results suggest that CEACAM1 differentially regulates formation of the VM-like network between cancer cell types and implicate CEACAM1 as a novel therapeutic target in malignant cancer.

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CEACAM1 is not expressed in HT1080 cells, and overexpression of CEACAM1 in HT1080 cells suppresses vasculogenic mimicry.

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CEACAM1 is highly expressed in SK-MEL-28 cells, and deletion of CEACAM1 in SK-MEL-28 cells abolishes vasculogenic mimicry.

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CEACAM1 regulates vasculogenic mimicry in a cell-dependent manner.

A549 cells adapted to high nitric oxide show reduced surface CEACAM expression and altered adhesion and migration properties

The migration and adhesion properties of tumors affect their metastatic rate. In the present study, we investigated carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 1, 5, and 6 expression in high nitric oxide (HNO)-adapted lung cancer cells compared to parent cells. We observed high transcript levels of CEACAM 1 (4S, 4L), CEACAM 5, and CEACAM 6 in HNO cells compared to parent cells. However, the surface expression was low in HNO cells. Interestingly, the intracellular protein levels were high for these three CEACAMs. We confirmed these results with immunohistochemical experiments. Further, the adhesion and migration assays showed reduced clumping in HNO-adapted A549 (A549-HNO) cells and faster migration rates, respectively. These results document the altered adhesion and migration properties of cells adapted to HNO. Further, our studies also indicate a dynamic regulation of CEACAM protein expression and surface transport in HNO cells.

Loss of carcinoembryonic antigen-related cell adhesion molecule 1 expression predicts metachronous pulmonary metastasis and poor survival in patients with hepatoblastoma

PURPOSE

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a member of the carcinoembryonic antigen family of immunoglobulin-like adhesion molecules. The aim of this study was to test the hypothesis that loss of CEACAM1 expression in hepatoblastoma cells may promote hematogeneous metastasis and function as an adverse prognostic factor.

METHODS

Immunohistochemical expression of CEACAM1 in surgically resected specimens from 19 patients with hepatoblastoma was examined retrospectively. The CEACAM1 expression in the epithelial area of the tumor was classified into 2 categories as follows: diffuse expression, characterized by positive staining throughout the tumor specimen, or loss of expression, in which there were distinct areas of negative staining within the tumor specimen.

RESULTS

Of the 19 patients, 12 were classified as having tumors with diffuse expression, and 7 had loss-of-expression tumors. Survival after treatment was significantly worse in patients with tumors with loss of CEACAM1 expression (cumulative 5-year survival rate, 29%) than in patients with diffuse CEACAM1 expression (cumulative 5-year survival rate, 92%; P = .0062). Loss of CEACAM1 expression was a significant risk factor for metachronous pulmonary metastases (P = .0105).

CONCLUSIONS

Loss of CEACAM1 expression may reflect a high metastatic potential and thus indicate a poor prognosis for patients with hepatoblastoma.

Expression of Aurora B and alternative variant forms in hepatocellular carcinoma and adjacent tissue

Surgical resection is the effective treatment modality for hepatocellular carcinoma (HCC); however, rapid recurrence of the tumors are frequently observed even after apparently curative resection. The recurrence and prognostic assessment of patients with HCC after resection is an important clinical issue. We recently reported that aberrant expression of Aurora B is observed in primary HCC, and that it can be a predictive factor for HCC recurrence exceeding Milan criteria after curative hepatectomy. In this study we investigated the expression of the newly observed Aurora B splicing variant forms in HCC, and their roles in hepatocarcinogenisis. The expression of Aurora B and splicing variant forms were screened in 125 HCC patients (94 chronic hepatitis with cirrhosis background liver specimens), 18 metastatic liver cancer patients and 16 normal liver specimens by cDNA microarray, reverse transcription -- polymerase chain reaction (RT-PCR) and Real time quantitative Reverse Transcription PCR (qRT-PCR). The results showed that expression of Aurora B splicing variant 2 (AURKB-Sv2) variant form was absent in normal liver and was higher in metastatic liver cancer than HCC. This aberrant expression was associated with the advanced stages of HCC (P < 0.01), correlated with a poor outcome (P = 0.008) and short disease-free period (P = 0.018). Furthermore, AURKB-Sv2 variant form is associated with a higher level of serum alpha-fetoprotein, protein induced by vitamin K absence or antagonist-II (PIVKAII), tumor capsular invasion, multiple tumor formation and at an age younger than those with other variant forms (P < 0.05). The results thus suggest that AURKB-Sv2 variant form is more significantly associated with the advanced stages of HCC than others and is a marker of poor prognosis. Founded in the tumor capsular invasion and multiple tumor regions, suggests that this might play a role in enhancing multiple malignant tumor formation and recurrence of HCC in hepatocarcinogenesis. This is the first study to report clinicopathological significance of aberrant expression of AURKB-Sv2 variant form in hepatocellular carcinoma.

Intestinal tumor progression is promoted by decreased apoptosis and dysregulated Wnt signaling in Ceacam1-/- mice

The carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is downregulated in colonic and intestinal hyperplastic lesions as well as in other cancers, where it functions as a tumor suppressor. To investigate the functions of CEACAM1 in the normal intestine and in intestinal tumors, we generated a compound knockout mouse model and examined both Ceacam1(-/-) and Apc(1638N/+):Ceacam1(-/-) mice. Ceacam1(-/-) intestinal cells exhibited a significant decrease in apoptosis, with no change in proliferation or migration, however. Compound Apc(1638N/+):Ceacam1(-/-) mice demonstrated an increase in intestinal tumor multiplicity and tumor progression. Increases in intussusceptions and desmoid lesions were also observed. We have shown that CEACAM1-L associates with beta-catenin by co-immunoprecipitation and colocalization in CEACAM1-L-transfected CT26 and CT51 mouse colon carcinoma cells. Ceacam1(-/-) enterocytes displayed decreased glycogen synthase kinase 3-beta activity with corresponding nuclear localization of beta-catenin. Increased T-cell factor/Lef transcriptional activity was observed in CEACAM1-null CT51 colonic cells and in Caco2 colon cancer cells in which CEACAM1 was downregulated. A significant increased expression in c-Myc and cyclin D1 targets of the Wnt signaling pathway was also revealed in the Ceacam1(-/-) intestine. CEACAM1 therefore actively participates in Wnt signaling in intestinal cells and its downregulation in intestinal tissue contributes to malignancy by augmenting tumor multiplicity and progression.