Current treatment strategies in elderly patients with metastatic colorectal cancer

Interfering with S100B-effector protein interactions for cancer therapy

S100 calcium-binding protein B (S100B) is overexpressed in various malignant tumors, where it regulates cancer cell proliferation and metabolism by physical interactions with other molecules. Interfering with S100B-effector protein interactions is a potential strategy to treat malignant tumors. Although some S100B inhibitors have been discovered by virtual screening (VS), most target the S100B-p53 interaction. Hence, there is scope for the discovery of other S100B-effector protein interaction modulators for malignant tumors. In this review, we provide an overview of S100B-effector protein interaction inhibitor discovery using VS and discuss promising S100B-effector protein interaction targets that permit in silico analysis for drug discovery.

Age and sex differences in microRNAs expression during the process of thymus aging

The gender-biased thymus involution and the importance of microRNAs (miRNAs, miRs) expression in modulating the thymus development have been reported in many studies. However, how males and females differ in so many ways in thymus involution remains unclear. To address this question, we investigated the miRNA expression profiles in both untreated 3- and 12-month-old female and male mice thymuses. The results showed that 7 and 18 miRNAs were defined as the sex- and age-specific miRNAs, respectively. The expression of miR-181c-5p, miR-20b-5p, miR-98b-5p, miR-329-3p, miR-341-5p, and miR-2137 showed significant age-difference in mice thymus by quantitative polymerase chain reaction. High expression levels of miR-2137 were detected in mice thymic epithelial cells and gradually increased during the process of thymus aging. MiR-27b-3p and miR-378a-3p of the female-biased miRNAs were confirmed as the sex- and estrogen-responsive miRNAs in mice thymus in vivo. Their potential target genes and the pathway were identified by the online software. Possible regulation roles of sex- and age-specific miRNA expression during the process of thymus aging were discussed. Our results suggested that these miRNAs may be potential biomarkers for the study of sex- and age-specific thymus aging and involution.

Prospective evaluation of a colorectal cancer nurse follow-up clinic

AIM

Colorectal Nurse Specialist (CNS) clinics for postoperative follow up of colorectal cancer aim to maintain clinical efficacy while reducing costs. We prospectively studied the efficacy and financial implications of such a clinic.

METHOD

This was a prospective study of all patients attending CNS clinics over 3 years. A lower-risk protocol for patients with Dukes A was used over 3 years and a higher-risk protocol for patients with Dukes B, C or D was used over 5 years. Department of Health Pricing Charts were used to cost the follow-up protocols, and adjustment was performed to calculate the cost of each quality adjusted life year (QALY) gained.

RESULTS

One hundred and ninety-three patients entered into this nurse-led follow-up protocol implemented by the CNS clinic between 2005 and 2007. The Dukes stages and proportions of patients in each stage were as follows: stage A, 13%; stage B, 8%; stage C, 36.3%; and stage D, 9.3%. Ninety-seven per cent underwent curative treatment and 2.6% had palliative treatment. Twenty-one per cent of patients developed recurrent disease. Overall actuarial 5-year survival was 80% and recurrences had a 30% 5-year actuarial survival. The total cost per patient for 3 years of follow up was £1506 and £1179 for lower-risk rectal and nonrectal cancers, respectively. The adjusted cost for each QALY gained for lower-risk tumours was £1914. The total cost per patient with higher-risk tumours was £1814 and £1487 for rectal and nonrectal tumours, respectively. The adjusted cost for each QALY gained was £2180 for higher-risk tumours.

CONCLUSIONS

This clinic demonstrated cost-effective detection of recurrent disease. Computed tomography (CT) was the most sensitive alert test. As all recurrences were detected within 4 years, we suggest that this is the indicated time to follow up.

S100B protein expressions as an independent predictor of early relapse in UICC stages II and III colon cancer patients after curative resection

BACKGROUND

S100 calcium-binding proteins such as S100B are elevated in primary malignant melanoma and are used as tumor markers for malignant melanoma and numerous other cancers. The purpose of this study was to identify the novel predictors of early relapse in UICC stages II and III colon cancer patients and thus to identify a subgroup of patients who are at high risk for postoperative early relapse.

METHODS

Clinicopathological factors and S100B expression by immunohistochemical staining were retrospectively analyzed in 357 postoperative UICC stages II and III colon cancer patients to determine the predictors of early relapse.

RESULTS

Of 357 patients, 114 patients developed postoperative relapse during the follow-up period. Among 114 relapsed colon cancer patients, postoperative early relapse and non-early relapse were found in 56 patients (49.1%) and 58 patients (50.9%), respectively. Multivariate Cox proportional hazards analysis revealed that the presence of vascular invasion (P = .025; hazard ratio [HR], 5.532; 95% confidence interval [95% CI], 1.985-14.729), high postoperative CEA levels (P = .019; HR, 6.845; 95% CI, 2.393-15.256), and S100B overexpression (P < .001; HR, 26.250; 95% CI, 7.463-96.804) were demonstrated to be independent predictors of postoperative early relapse. Furthermore, postoperative relapsed colon cancer patients with S100B overexpression were demonstrated to have significantly lower overall survival rates than those without S100B overexpression (P < .001).

CONCLUSIONS

This study suggests that S100B protein expression is a crucial predictor of early relapse in UICC stages II and III postoperative colon cancer patients and thus could help to define patients with this tumor entity who would benefit from enhanced follow-up and therapeutic program(s).

Transcriptome analysis of murine thymocytes reveals age-associated changes in thymic gene expression

The decline in adaptive immunity, naïve T-cell output and a contraction in the peripheral T cell receptor (TCR) repertoire with age are largely attributable to thymic involution and the loss of critical cytokines and hormones within the thymic microenvironment. To assess the molecular changes associated with this loss of thymic function, we used cDNA microarray analyses to examine the transcriptomes of thymocytes from mice of various ages ranging from very young (1 month) to very old (24 months). Genes associated with various biological and molecular processes including oxidative phosphorylation, T- and B- cell receptor signaling and antigen presentation were observed to significantly change with thymocyte age. These include several immunoglobulin chains, chemokine and ribosomal proteins, annexin A2, vav 1 and several S100 signaling proteins. The increased expression of immunoglobulin genes in aged thymocytes could be attributed to the thymic B cells which were found to be actively producing IgG and IgM antibodies. Upon further examination, we found that purified thymic T cells derived from aged but not young thymi also exhibited IgM on their cell surface suggesting the possible presence of auto-antibodies on the surface thymocytes with advancing age. These studies provide valuable insight into the cellular and molecular mechanisms associated with thymic aging.

A stochastic model for cancer stem cell origin in metastatic colon cancer

Human cancers have been found to include transformed stem cells that may drive cancer progression to metastasis. Here, we report that metastatic colon cancer contains clonally derived tumor cells with all of the critical properties expected of stem cells, including self-renewal and the ability to differentiate into mature colon cells. Additionally, when injected into mice, these cells initiated tumors that closely resemble human cancer. Karyotype analyses of parental and clonally derived tumor cells expressed many consistent (clonal) along with unique chromosomal aberrations, suggesting the presence of chromosomal instability in the cancer stem cells. Thus, this new model for cancer origin and metastatic progression includes features of both the hierarchical model for cancerous stem cells and the stochastic model, driven by the observation of chromosomal instability.

Colorectal cancer progression correlates with upregulation of S100A11 expression in tumor tissues

BACKGROUND AND AIMS

Early detection and treatment of human colorectal cancers remain a challenge. Identification of new potential markers may help in the diagnosis of colorectal cancer.

MATERIALS AND METHODS

By comparative two-dimensional gel electrophoresis using extracts from colorectal tumor and adjacent normal tissues, we identified a calcium-binding protein, S100A11, which was highly expressed in colorectal cancer compared with adjacent normal tissues. We expanded our study in 89 clinical colorectal tumor samples to validate this finding and correlates S100A11 expression in human colorectal cancer tissues with various stages of the tumor by Western blotting and immunohistochemical staining.

RESULTS

We identified a calcium-binding protein, S100A11, which was highly expressed in colorectal cancer compared with adjacent normal tissues. S100A protein was expressed predominantly in the cytoplasm of normal tissue; however, it was expressed in both the nuclei and cytoplasm of colorectal cancer. S100A11 level in colorectal cancer tissue was increased following stage progression of the disease.

CONCLUSION

These findings suggest S100A11 could be helpful in the pathological study of colorectal cancer, especially for the classification of different stages in colorectal cancer.

High efficiency reconstitution of a human-mouse chimeric Fab of CAb-1 antibody specific to human colon cancer

Monoclonal antibody (mAb) has been widely applied in the treatment of human diseases, especially in malignant tumours. However, most antibodies produced in mouse by hybridoma technology might induce severe human anti-mouse reactions. We had reported a murine mAb CAb-1 of therapeutic interest for its specifically binding to a cell surface glycoprotein of human colon cancer. Here, we attempted to generate a reconstituted human-mouse chimeric Fab (cFab) of CAb-1 in vitro to reduce its antigenicity and increase its capacity of penetration. First, the genes of heavy and light chain variable region (VH, VL) of CAb-1 were cloned. Then, the chimeric light chain (cL) and Fd (cFd) were constructed and expressed in Escherichia coli. Finally, the reconstituted cFab was obtained by gradient dialysis of the mixture of cFd and cL. SDS-PAGE and western blot analysis showed the reconstituted cFab with a recovery rate of 70.2% when the initial total concentration of cL and cFd proteins to be 100 microg/ml. The reconstituted cFab maintained the affinity and specificity to colon cancer cells compared with its parental antibody as determined by immunostaining analysis, FACS and ELISA. Our results established a foundation for further application of the cFab in diagnosis and treatment of colon cancer.