Cannot Target What Cannot Be Seen: Molecular Imaging of Cancer Stem Cells

Age-related features of lung cancer treatment using reprogrammed CD8 positive T cells in mice subjected to injection of Lewis lung carcinoma cells

BACKGROUND

Awareness of age-related features of carcinogenesis and the importance of cellular immunity is crucial for developing effective antitumor therapies for specific patient groups.

METHODS

In this study, we examined different populations of cancer stem cells (CSCs) and circulating tumor cells (CTCs) in "young" (8-10 weeks) and "aged" (80-82 weeks) C57BL/6 male mice. We used an orthotopic model of Lewis lung carcinoma (LLC) to evaluate the effectiveness of cell therapy targeting lung cancer through reprogrammed CD8-positive T cells (rCD8+ T cells) in mice from two different ages.

RESULTS

The findings revealed that tumor progression with age is primarily caused by impaired recruitment of T cells to the lungs. Additionally, a lower number of CTCs and CSCs were observed in younger mice compared to the older mice. The antitumor effect of rCD8+ T cells in aged mice was found to be inferior to that in young mice, which can be attributed to the reduced impact of therapy on specific CSCs populations.

CONCLUSIONS

These results offer new insights into the treatment of lung cancer using rCD8+ T cells. Considering the age-related characteristics influencing disease progression, this therapy has the potential to significantly enhance the effectiveness of treatment methods.

Cancer Stem Cells from Definition to Detection and Targeted Drugs

Cancers remain the second leading cause of mortality in the world. Preclinical and clinical studies point an important role of cancer/leukaemia stem cells (CSCs/LSCs) in the colonisation at secondary organ sites upon metastatic spreading, although the precise mechanisms for specific actions are still not fully understood. Reviewing the present knowledge on the crucial role of CSCs/LSCs, their plasticity, and population heterogeneity in treatment failures in cancer patients is timely. Standard chemotherapy, which acts mainly on rapidly dividing cells, is unable to adequately affect CSCs with a low proliferation rate. One of the proposed mechanisms of CSC resistance to anticancer agents is the fact that these cells can easily shift between different phases of the cell cycle in response to typical cell stimuli induced by anticancer drugs. In this work, we reviewed the recent studies on CSC/LSC alterations associated with disease recurrence, and we systematised the functional assays, markers, and novel methods for CSCs screening. This review emphasises CSCs' involvement in cancer progression and metastasis, as well as CSC/LSC targeting by synthetic and natural compounds aiming at their elimination or modulation of stemness properties.

Opportunities in Cancer Therapies: Deciphering the Role of Cancer Stem Cells in Tumour Repopulation

Tumour repopulation during treatment is a well acknowledged yet still challenging aspect of cancer management. The latest research results show clear evidence towards the existence of cancer stem cells (CSCs) that are responsible for tumour repopulation, dissemination, and distant metastases in most solid cancers. Cancer stem cell quiescence and the loss of asymmetrical division are two powerful mechanisms behind repopulation. Another important aspect in the context of cancer stem cells is cell plasticity, which was shown to be triggered during fractionated radiotherapy, leading to cell dedifferentiation and thus reactivation of stem-like properties. Repopulation during treatment is not limited to radiotherapy, as there is clinical proof for repopulation mechanisms to be activated through other conventional treatment techniques, such as chemotherapy. The dynamic nature of stem-like cancer cells often elicits resistance to treatment by escaping drug-induced cell death. The aims of this scoping review are (1) to describe the main mechanisms used by cancer stem cells to initiate tumour repopulation during therapy; (2) to present clinical evidence for tumour repopulation during radio- and chemotherapy; (3) to illustrate current trends in the identification of CSCs using specific imaging techniques; and (4) to highlight novel technologies that show potential in the eradication of CSCs.