CD26-positive/CD326-negative circulating cancer cells as prognostic markers for colorectal cancer recurrence

Multiparameter flow cytometric detection and analysis of rare cells in in vivo models of cancer metastasis

Rapid and reliable circulating tumor cell (CTC) and disseminated tumor cell (DTC) detection are critical for rigorous evaluation of in vivo metastasis models. Clinical data show that each step of the metastatic cascade presents increasing barriers to success, limiting the number of successful metastatic cells to fewer than 1 in 1,500,000,000. As such, it is critical for scientists to employ approaches that allow for the evaluation of metastatic competency at each step of the cascade. Here, we present a flow cytometry-based method that enables swift and simultaneous comparison of both CTCs and DTCs from single animals, enabling evaluation of multiple metastatic steps within a single model system. We present the necessary gating strategy and optimized sample preparation conditions necessary to capture CTCs and DTCs using this approach. We also provide proof-of-concept experiments emphasizing the appropriate limits of detection of these conditions. Most importantly, we successfully recover CTCs and DTCs from murine blood and bone marrow. In Supplemental materials, we expand the applicability of our method to lung tissue and exemplify a potential multi-plexing strategy to further characterize recovered CTCs and DTCs. This approach to multiparameter flow cytometric detection and analysis of rare cells in in vivo models of metastasis is reproducible, high throughput, broadly applicable, and highly adaptable to a wide range of scientific inquiries. Most notably, it simplifies the recovery and analysis of CTCs and DTCs from the same animal, allowing for a rapid first look at the comparative metastatic competency of various model systems throughout multiple steps of the metastatic cascade.

Prognostic value of circulating tumor cells in patients with recurrent and metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND

The detection of circulating tumor cells (CTCs) has been employed in prognosticating the likelihood of recurrence and metastasis in colorectal cancer (CRC). Nonetheless, the findings remain enigmatic. This meta-analysis aims to systematically assess the predictive utility of CTCs detection in postoperative recurrence and metastasis among CRC patients.

METHODS

A comprehensive search of PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Cochrane Library was conducted from inception to March 2023. Pooled estimates including sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and summary receiver operating characteristic curve were computed to gauge the predictive value. The QUADAS-2 tool was employed to appraise bias risks in individual studies. The assessment of publication bias in the included literature was performed using Deek's funnel plot.

RESULTS

The study encompassed 16 articles and 2037 patients. After synthesizing the pertinent indices, CTCs monitoring demonstrated sensitivity and specificity of 0.71 (95% confidence interval [CI], 0.62-0.79) and 0.71 (95% CI, 0.55-0.83), respectively. The corresponding values for positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 2.4 (95% CI, 1.5-4.0), 0.41 (95% CI, 0.29-0.58), and 6 (95% CI, 3-13). The summary receiver operating characteristic curve yielded an area under the curve of 0.76 (95% CI, 0.72-0.80). Deek's funnel plot analysis revealed no significant evidence of publication bias (P = .42).

CONCLUSION

This investigation underscores the potential of CTCs detection as a noninvasive modality to efficaciously prognosticate postoperative recurrence and metastasis in CRC.

CD26 Induces Colorectal Cancer Angiogenesis and Metastasis through CAV1/MMP1 Signaling

CD26 has been reported as a marker for colorectal cancer stem cells endowed with tumor-initiating properties and capable of colorectal cancer (CRC) metastasis. In this study, we investigated the functional effect of CD26 on CRC angiogenesis and metastasis, and the potential underlying mechanism. The functional effects of CD26 overexpression or repression were determined by a wound healing experiment, and cell migration and invasion assays in vitro and in mouse models. Differentially expressed genes regulated by CD26 were identified by genome-wide mRNA expression array and validated by quantitative PCR. CD26 functionally regulated CRC cell migration and invasion in vitro and angiogenesis and metastasis in vivo. Genome-wide mRNA expression array and qPCR showed that MMP1 was up-regulated in CD26+ subpopulation, and a subsequent experiment demonstrated the regulatory effect of CD26 on MMP1 in CRC cell lines with CD26 repression or overexpression. Furthermore, overexpression of CAV1 abrogated the CD26-regulated MMP1 induction in CRC cell lines. This study demonstrated the functional roles of CD26 in inducing CRC migration, invasion, angiogenesis and metastasis and identified the potential involvement of MMP1 and CAV1 in such process. CD26 is an attractive therapeutic target for combating tumor progression to improve the prognosis of CRC patients.

Molecular features and gene expression signature of metastatic colorectal cancer (Review)

Uncontrollable metastatic outgrowth process is the leading cause of mortality worldwide, even in the case of colorectal cancer. Colorectal cancer (CRC) accounts for approximately 10% of all annually diagnosed cancers and 50% of CRC patients will develop metastases in the course of disease. Most patients with metastatic CRC have incurable disease. Even if patients undergo resection of liver metastases, the 5‑year survival rate ranges from 25 to 58%. Next‑generation sequencing of tumour specimens from large colorectal cancer patient cohorts has led to major advances in elucidating the genomic landscape of these tumours and paired metastases. The expression profiles of primary CRC and their metastatic lesions at both the gene and pathway levels were compared and led to the selection of early driver genes responsible for carcinogenesis and metastasis‑specific genes that increased the metastatic process. The genetic, transcriptional and epigenetic alteration encoded by these genes and their combination influence many pivotal signalling pathways, enabling the dissemination and outgrowth in distant organs. Therapeutic regimens affecting several different active pathways may have important implications for therapeutic efficacy.

The mechanism of sitagliptin inhibition of colorectal cancer cell lines' metastatic functionalities

The cell membrane glycoprotein CD26 with peptidase activity (DPP4) and/or its soluble CD26/DPP4 counterpart expression and/or activity are altered in several cancers. Its role in metastasis development was recently highlighted by the discovery of CD26⁺ cancer stem cell subsets and the fact that clinical DPP4 inhibitors showed antimetastatic effects in animal models. Also, diabetic patients treated with the DPP4 inhibitor sitagliptin showed greater overall survival after colorectal or lung cancer surgery than patients under other diabetic therapies. However, the mechanism of action of these inhibitors in this context is unclear. We studied the role of CD26 and its DPP4 enzymatic activity in malignant cell features such as cell-to-cell homotypic aggregation, cancer cell motility, and invasion in a panel of human colorectal cancer (CRC) cell lines, avoiding models that include the physiological role of DPP4 in chemotaxis. Present results indicate that CD26 participates in the induction of cell invasion, motility, and aggregation of CD26-positive CRC cell lines. Moreover, only invasion and motility assays, which are collagen matrix-dependent, showed a decrease upon treatment with the DPP4 inhibitor sitagliptin. Sitagliptin showed opposite effects to those of transforming growth factor-β1 on epithelial-to-mesenchymal transition and cell cycle, but this result does not explain its CD26/DPP4-dependent effect. These results contribute to the elucidation of the molecular mechanisms behind sitagliptin inhibition of metastatic traits. At the same time, this role of sitagliptin may help to define areas of medicine where DPP4 inhibitors might be introduced. However, they also suggest that additional tools against CD26 as a target might be used or developed for metastasis prevention in addition to gliptins.

Flow cytometry-based analysis of tumor-leukocyte ratios in peritoneal fluid from patients with advanced gastric cancer

Background

The frequency of tumor cell dissemination in the peritoneal cavity is critically related to the progression of peritoneal metastases (PM). Recently, flow cytometry (FCM) has been successfully used to detect tumor cells in malignant effusions.

Methods

A total of 143 single cell suspensions derived from ascites or peritoneal lavages from patients with advanced gastric cancer (GC) were stained with monoclonal antibodies to CD45 and to CD326 as well as 4,6‐diamidino‐2‐phenylindole (DAPI) and FVS780. Using FCM, tumor‐leukocyte ratio (TLR) were calculated from CD45(−)CD326(+) tumor cell counts/ CD45(+)CD326(+) leukocyte counts in DAPI (+) FVS780(−) gated area. In 54 patients, the ratios of CD11b(+), CD4(+) and CD8(+) cells in CD45(+) leukocytes were evaluated in parallel.

Results

TLR of 69 patients with PM were significantly higher than those of 74 without PM (p < .001) and log(TLR) showed strong correlation with peritoneal cancer index scores in 51 PM (+) patients (r = 0.439). TLR in PM (+) patients also correlated with the ratio of CD11b (+) myeloid cells (r = 0.547), and correlated inversely with those of CD4(+) (r = −0.490) and CD8(+) T cells (r = −0.648). In PM (−) patients who underwent gastrectomy, TLR never exceeded 0.1% in patients with primary GC without serosal involvement (<T4). However, TLR in patients with T4 GC were significantly higher (p < .05) and peritoneal recurrence occurred in 6/8 patients whose TLR exceeded 0.1%.

Conclusion

TLR in peritoneal fluid reflects tumor burden and the immune environment in peritoneal cavity. Multicolor FCM may provide additional information which can be used for the treatment of the patients with PM.

In silico Analysis, Molecular Docking, Molecular Dynamic, Cloning, Expression and Purification of Chimeric Protein in Colorectal Cancer Treatment

Introduction

Colorectal cancer (CRC) is a type of cancer in humans that leads to high mortality and morbidity. CD166 and CD326 are immunoglobulins that are associated with cell migration. These molecules are included in tumorigenesis of CRC and serve a great marker of CRC stem cells. In the present study, we devised a novel chimeric protein including the V₁-domain of the CD166 and two epitopes of CD326 to use in diagnostic or therapeutic applications.

Methods

In silico techniques were launched to characterize the properties and structure of the protein. We have predicted physicochemical properties, structures, stability, MHC class I binding properties and ligand-receptor interaction of this chimeric protein by means of computational bioinformatics tools and servers. The sequence of chimeric gene was optimized for expression in prokaryotic host using online tools and cloned into pET-28a plasmid. The recombinant pET28a was transformed into the E. coli BL21DE3. Expression of recombinant protein was examined by SDS-PAGE and Western blotting.

Results

The designed chimeric protein retained high stability and the same immunogenicity as of the original proteins. Bioinformatics data indicated that the epitopes of the synthetic chimeric protein might induce B-cell- and T-cell-mediated immune responses. Furthermore, a gene was synthesized using the codon bias of a prokaryotic expression system. This synthetic gene expressed a bacterial expression system. The recombinant protein with molecular weights of 27kDa was expressed and confirmed by anti-his Western blot analysis.

Conclusion

The designed recombinant protein may be useful as a CRC diagnostic tool and for developing a protective vaccine against CRC.

Molecular characterization of lung cancer: A two-miRNA prognostic signature based on cancer stem-like cells related genes

Lung cancer is one of the deadliest cancers worldwide. To increase the survival rate of lung cancer, it is necessary to explore specific prognosis markers. More and more evidence finds that noncoding RNA is closely associated with the survival of lung cancer, and cancer stem cells (CSCs) also play a significant role in the progress of lung cancer. The objective of this study is to find CSLCs genes that affect the prognosis of lung cancer. The differential expression of long noncoding RNAs (lncRNAs), microRNAs (miRNAs), messenger RNAs (mRNAs) in the Cancer Genome Atlas (TCGA) database and differential expression data from microarray of CD326⁺ and CD326^- A549 cell are intersected to identify stable and consistent expression genes (2 lncRNAs, 15 miRNAs, and 134 mRNAs). The intersection of lncRNAs and miRNAs is analyzed by univariate and multivariate Cox regression to obtained prognostic genes. Two miRNAs (miR-30b-5p and miR-29c-3p) are significantly correlated with the overall survival rate. Then using these two miRNAs to construct a risk score model as a prognosis signature of lung cancer. Subsequently, we analyzed the association between two miRNAs and clinical information of lung cancer patients, of which T stage, Neoplasm cancer and risk score (P < .05) can be used as independent prognostic indicators of lung cancer. Finally, target genes of 2 miRNAs and 134 mRNAs were annotated with Gene Ontology and analyzed with Kyoto Encyclopedia of Genes and Genomes pathway, and verified with the GEO database. In summary, this study illustrates the role of miRNAs in the promotion of lung cancer by CSCs, which is important to find molecular biomarkers of lung cancer.

Surface expression marker profile in colon cancer cell lines and sphere-derived cells suggests complexity in CD26+ cancer stem cells subsets

Taking advantage of eight established cell lines from colorectal cancer patients at different stages of the disease and the fact that all of them could form spheres, cell surface biomarkers of cancer stem cells and epithelial-mesenchymal transition were tested. The aim was to investigate cancer stem cells and metastatic stem cells in order to provide functional characterization of circulating tumor cells and promote the development of new anti-metastatic therapies. Our model showed an important heterogeneity in EpCAM, CD133, CD44, LGR5, CD26 and E-cadherin expression. We showed the presence of a subset of E-cadherin⁺ (some cells being E-cadherin^high) expressing CD26⁺ (or CD26^high) together with the well-known CSC markers LGR5 and EpCAM^high, sometimes in the absence of CD44 or CD133. The already described CD26⁺/E-cadherin^low or ^negative and CD26⁺/EpCAM⁻/CD133⁻ subsets were also present. Cell division drastically affected the expression of all markers, in particular E-cadherin, so new-born cells resembled mesenchymal cells in surface staining. CD26 and/or dipeptidyl peptidase 4 inhibitors have already shown anti-metastatic effects in pre-clinical models, and the existence of these CD26⁺ subsets may help further research against cancer metastasis.

Summary: In our model of eight established cell lines from colorectal cancer patients we show the presence of different putative cancer stem cell (CSC) subsets with expression of CD26/DPP4.

Effect of FOLFOX on minimal residual disease in Stage III colon cancer and risk of relapse

Introduction

25% of Stage III colon cancer patients relapse within 5 years due to minimal residual disease (MRD) not eliminated by surgery and chemotherapy. We hypothesise that sub-types of MRD, defined by circulating tumour cells (CTCs) and bone marrow micro-metastasis (mM) have different types and kinetics of relapse.

Patients and Methods

One month of curative surgery and 1 month after completing six cycles of FOLFOX chemotherapy blood and bone marrow samples were taken to detect CTCs and mM using immunocytochemistry with anti-carcino-embryonic antigen (CEA). Follow up was up to 5 years or disease progression defined as new images on CT scanning. Survival curves using Kaplan–Meier (KM) and Restricted Mean Survival Time (RMST) were calculated for three prognostic groups: CTC and mM negative, CTC negative mM positive, and CTC positive.

Results

76 patients (39 men) participated, mean age 67 years, median follow-up 3.6 years. The response to chemotherapy was heterogeneous and MRD pre-treatment did not predict response to therapy. Of 21 patients MRD (−), 20 remained MRD negative and one patient became mM (+); of 21 patients mM (+), 10 became MRD (−), 8 remained the same and 3 became CTC (+); of the 34 CTC positive, 8 became MRD (−), 8 with only mM, and 18 remained positive.

After chemotherapy, 38 patients were negative for CTC and mM, 17 were positive for only mM, and 21 for CTCs. For the whole cohort, the 5 year KM was 58%, the median survival was not reached. For the three prognostic groups, the KM 5-year survivals were 87%, 58%, and 4%, respectively, the median survival for patients MRD negative and mM only was not reached. RMST for the whole cohort was 3.6 years, for the three prognostic groups the RMST was 4.6 years, 4.0 years, and 1.5 years, respectively. Serum CEA was significantly higher pre-surgery in the CTC positive group. There were no significant differences with respect to age or sex between the three groups.

Conclusions

MRD subtypes pre-chemotherapy did not predict treatment response. Post-chemotherapy MRD subtypes were associated with the pattern of failure and time to failure. MRD negative patients had an excellent prognosis with 87% disease-free survival at 5 years. Those with only mM had a similar outcome up to 2 years and then were at increasing risk of late failure. Patients who were CTC positive had a high risk of early failure. MRD subclassification may be useful to define the risk of relapse in Stage III colon cancer patients and warrants further studies with a larger number of patients.

Heterogeneity of Colon Cancer Stem Cells

Colorectal cancer (CRC) remains the fourth leading cause of cancer death worldwide. Cancer stem cells (CSCs) have attracted a great deal of interest because of their potential clinical implications in a range of cancers, including CRC. CSCs were initially considered to be cell populations with well-defined phenotypic and molecular characteristics. However, accumulating evidence suggests that CSCs represent a phenotypically and functionally heterogeneous population. Recent studies also demonstrate colorectal CSCs to be dynamic rather than static populations that are continuously altered by various extrinsic factors in addition to intrinsic cellular factors such as genetic and epigenetic alterations. Thus, CSCs do not represent a fixed target population any longer, and their heterogeneous and dynamic nature present a serious problem in establishing specific therapeutic strategies. This chapter summarizes past and current literature related to CSC population heterogeneity and dynamics in CRC tissues, including evidence of the presence of distinct CSC subpopulations and signaling pathways and intra- and extra-tumoral factors involved in the regulation of CSCs in cancer tissues.

Multifaceted Interpretation of Colon Cancer Stem Cells

Colon cancer is one of the leading causes of cancer-related deaths worldwide, despite recent advances in clinical oncology. Accumulating evidence sheds light on the existence of cancer stem cells and their role in conferring therapeutic resistance. Cancer stem cells are a minor fraction of cancer cells, which enable tumor heterogeneity and initiate tumor formation. In addition, these cells are resistant to various cytotoxic factors. Therefore, elimination of cancer stem cells is difficult but essential to cure the malignant foci completely. Herein, we review the recent evidence for intestinal stem cells and colon cancer stem cells, methods to detect the tumor-initiating cells, and clinical significance of cancer stem cell markers. We also describe the emerging problems of cancer stem cell theory, including bidirectional conversion and intertumoral heterogeneity of stem cell phenotype.

Suppression of CD26 inhibits growth and metastasis of pancreatic cancer

CD26/DPPIV is a glycosylated transmembrane type II protein and has a multitude of biological functions, while its impact on the malignant phenotypes of cancer cells has not been fully understood. This study aimed to investigate the effect of CD26 on growth and metastasis of pancreatic cancer cells in vitro and in vivo. We found in this study that CD26 expression was higher in cell lines that derived from the metastatic sites than those from the primary tumor sites. In specimens of pancreatic cancer patients, CD26 expression was higher in cancerous tissues than in paired normal tissues. In in vitro experiments, knockdown of CD26 expression inhibited cell growth, migration, invasion, colony formation, and increased cell apoptosis of pancreatic cancer cells. Knockdown of CD26 also decreased tumor growth and liver metastasis in vivo by using xenograft animal models. Suppression of CD26 could inhibit expression of epithelial-mesenchymal transition (EMT) regulatory genes. Our results indicated that CD26 may represent a new therapeutic target for pancreatic cancer.

Circulating tumor cells in head and neck cancer: A review

Carcinoma of the head and neck represents 3.5% of all cancers, and the vast majority of these tumors are squamous cell carcinoma (HNSCC). With a stable overall survival rate of 50% among all stages, there is continued interested in developing measures for early detection and disease aggressiveness. Circulating tumor cells (CTCs) have been identified as a potential marker for early metastatic disease, response to treatment, and surveillance in head and neck squamous cell carcinoma. In this article, techniques of CTC detection, applications of CTC technology, and outcomes of HNSCC patients will be discussed.