Putative anoikis-resistant subpopulations in colorectal carcinoma: a marker of adverse prognosis

Construction of prognostic risk markers for cervical cancer combined with anoikis-related genes and their clinical significance

CONTEXT

Several studies have demonstrated that anoikis affects the development, metastasis and prognosis of cancer.

AIMS

This study aimed to identify anoikis-related marker genes in cervical cancer (CC).

METHODS

Least absolute shrinkage and selection operator (LASSO) combined with Cox regression analysis was used to construct a prognostic model and analyse the independent prognostic ability of riskscore. Receiver operating characteristic curve (ROC) and survival curves were used to evaluate and verify the performance and accuracy of the model. The nomogram of CC prognostic model was drawn using riskscore combined with clinical information. We analysed the relationship between prognostic riskscore and immune infiltration level and analysed immunophenoscore. Finally, qRT-PCR assay was used to verify the feature genes.

KEY RESULTS

By Cox analysis, we found that the prognostic risk model could effectively predict the risk of CC in patients independently of other clinical factors. Both the levels of immune infiltration and the immunophenoscore were significantly lower in high-risk CC patients than those in low-risk patients, revealing that high-risk patients were likely to have bad response to immunotherapy. The qRT-PCR results of the feature genes were consistent with the results of gene expression in the database.

CONCLUSIONS

The prognostic model constructed, based on anoikis-related genes in CC, could predict the prognosis of CC patients.

IMPLICATIONS

The model described here can provide effective support for assessing prognostic risk and devising personalised protocols during clinical treatment.

Understanding and targeting anoikis in metastasis for cancer therapies

The development of effective treatments for cancers requires investigations for a more detailed and comprehensive understanding of the basic cellular mechanisms involved in carcinogenesis, cancer progression, and metastasis. One of those driving mechanisms is anoikis, a special type of apoptosis, which is induced by losing anchorage from the extracellular matrix (ECM). In other words, resisting death in detached cells (cells without ECM) forms an anoikis-resistant phenotype. Since the anoikis-resistance state compensates for the initial steps of cancer metastasis, this review aimed to discuss mechanisms of gaining anoikis/anoikis resistance phenotype in tumor cells. Finally, we highlighted the significance of anoikis in malignancies so as to provide clear insight into cancer diagnosis and therapy development.

Putative anoikis resistant subpopulations are enriched in lymph node metastases and indicate adverse prognosis in colorectal carcinoma

Anoikis refers to apoptosis induced by the loss of contact with the extracellular matrix. Anoikis resistance is essential for metastasis. We have recently shown that it is possible to quantitatively evaluate putative anoikis resistant (AR) subpopulations in colorectal carcinoma (CRC). Abundance of these multi-cell structures is an independent marker of adverse prognosis. Here, we have quantified putative AR subpopulations in lymph node (LN) metastases of CRC and evaluated their prognostic value and relationship with the characteristics of primary tumors. A case series included 137 unselected CRC patients, 54 with LN metastases. Areal densities (structures/mm²) of putative AR structures in primary tumors had been analyzed previously and now were determined from all nodal metastases (n = 183). Areal density of putative AR structures was higher in LN metastases than in primary tumors. Variation of the areal density within different LN metastases of a single patient was lower than between metastases of different patients. Abundance of putative AR structures in LN metastases was associated with shorter cancer specific survival (p = 0.013), and this association was independent of T and N stages. Abundance of putative AR structures in primary tumors and LN metastases had a cumulative adverse effect on prognosis. Enrichment of putative AR subpopulations in LN metastases suggest that in metastasis formation, there is a selection favoring cells capable of forming these structures. Higher intra-case constancy relative to inter-case variation suggests that such selection is stable in metastasis development. Our findings indirectly support the biological validity of our concept of putative AR structures.

A Case of Colonic Micropapillary Carcinoma with a High Frequency of Apoptosis

Colorectal micropapillary carcinoma (MPC) exhibits aggressive biological characteristics, with empty spaces and reversed polarity, similar to the poorly differentiated clusters (PDCs) formed from detached cancer cells. Epithelial-mesenchymal transition, which is involved in the cancer cell acquisition of apoptosis resistance, is closely linked with histological findings of MPC, PDCs, and tumor buds (TBs), with MPC and TBs considered as apoptosis-resistant features. However, we encountered a case of colonic MPC with frequent apoptosis. We examined the case using immunohistochemistry. In many of the tumor glands (TGs) of the MPC, empty spaces and tumor cell detachment toward the gland interior were observed. Moreover, TG ruptures were scattered, with PDCs adjacent to them. Apoptosis occurred mainly at the TG and PDC peripheries in the middle and deep tumor layers, and transforming growth factor beta 1 (TGF-β1) positivity was evident in those tumor cells. Cells positive for apoptosis-related M30 were distributed mainly in the deep layer with a significant PDC and TB presence. However, apoptosis and M30 positivity were low in the TBs. Non-tumorous bud components, especially those in the deep layer, had poor ability to promptly acquire apoptosis resistance. No nuclear β-catenin positivity was found in any of the tumor cells. Apoptosis has the potential to reciprocally produce MPC, PDCs, and TBs, with TGF-β1 involvement.