Mature Red Blood Cells Contain Long DNA Fragments and Could Acquire DNA from Lung Cancer Tissue

New insights into red blood cells in tumor precision diagnosis and treatment

Red blood cells (RBCs), which function as material transporters in organisms, are rich in materials that are exchanged with metabolically active tumor cells. Recent studies have demonstrated that tumor cells can regulate biological changes in RBCs, including influencing differentiation, maturation, and morphology. RBCs play an important role in tumor development and immune regulation. Notably, the novel scientific finding that RBCs absorb fragments of tumor-carrying DNA overturns the conventional wisdom that RBCs do not contain nucleic acids. RBC membranes are excellent biomimetic materials with significant advantages in terms of their biocompatibility, non-immunogenicity, non-specific adsorption resistance, and biodegradability. Therefore, RBCs provide a new research perspective for the development of tumor liquid biopsies, molecular imaging, drug delivery, and other tumor precision diagnosis and treatment technologies.

Target-responsive triplex aptamer nanoswitch enables label-free and ultrasensitive detection of antibody in human serum via lighting-up RNA aptamer transcriptions

Accurate and sensitive monitoring of the concentration change of anti-digoxigenin (Anti-Dig) antibody is of great importance for diagnosing infectious and immunological diseases. Combining a novel triplex aptamer nanoswitch and the high signal-to-noise ratio of lighting-up RNA aptamer signal amplification, a label-free and ultrasensitive fluorescent sensing approach for detecting Anti-Dig antibodies is described. The target Anti-Dig antibodies recognize and bind with the nanoswitch to open its triplex helix stem structure to release Taq DNA polymerase and short ssDNA primer simultaneously, which activates the Taq DNA polymerase to initiate downstream strand extension of ssDNA primer to yield specific dsDNA containing RNA promoter sequence. T7 RNA polymerase recognizes and binds to these promoter sequences to initiate RNA transcription reaction to produce many RNA aptamer sequences. These aptamers can recognize and bind with Malachite Green (MG) dye specifically and produce highly amplified fluorescent signal for monitoring Anti-Dig antibodies from 50 pM to 50 nM with a detection limit down to 33 pM. The method also exhibits high selectivity for Anti-Dig antibodies and can be used to discriminate trace Anti-Dig antibodies in diluted serum samples. Our method is superior to many immunization-based Anti-Dig antibody detection methods and thus holds great potential for monitoring disease progression and efficacy.

The war between the immune system and the tumor - using immune biomarkers as tracers

Nowadays, immunotherapy is one of the most promising anti-tumor therapeutic strategy. Specifically, immune-related targets can be used to predict the efficacy and side effects of immunotherapy and monitor the tumor immune response. In the past few decades, increasing numbers of novel immune biomarkers have been found to participate in certain links of the tumor immunity to contribute to the formation of immunosuppression and have entered clinical trials. Here, we systematically reviewed the oncogenesis and progression of cancer in the view of anti-tumor immunity, particularly in terms of tumor antigen expression (related to tumor immunogenicity) and tumor innate immunity to complement the cancer-immune cycle. From the perspective of integrated management of chronic cancer, we also appraised emerging factors affecting tumor immunity (including metabolic, microbial, and exercise-related markers). We finally summarized the clinical studies and applications based on immune biomarkers. Overall, immune biomarkers participate in promoting the development of more precise and individualized immunotherapy by predicting, monitoring, and regulating tumor immune response. Therefore, targeting immune biomarkers may lead to the development of innovative clinical applications.

Red Blood Cell-Derived Exosomal Oncogenic MicroRNA Promote Cancer Development and Progression

The role of red blood cells (RBCs) in tumorigenesis is poorly understood. We previously identified RBC-microRNAs with aberrations linked to lung cancer, including miR-93-5p. Here we find that miR-93-5p levels are elevated in RBC-derived exosomes among lung cancer patients and are associated with their shorter survivals. RBC-derived miR-93-5p transfers to cancer cells primarily through the exosomal pathway. The transferred RBC-miR-93-5p can target PTEN in cancer cells, and hence increase cell proliferation, invasion, and migration. RBC-derived miR-93-5p accelerates, whereas targeting miR-93-5p diminishes tumor growth in xenograft models. These findings reveal a novel biological function of RBCs in tumorigenesis, where they facilitate cancer progression by transferring the oncomiR via exosomes, thereby offering new diagnostic and treatment strategies for lung cancer.

Red blood cells function as reservoirs of tumor DNA

Novel screening techniques for early detection of lung cancer are urgently needed. Profiling circulating tumor cell-free DNA (ctDNA) has emerged as a promising tool for biopsy-free tumor genotyping. However, both the scarcity and short half-life of ctDNA substantially limit the sensitivity and clinical utility of ctDNA detection methodologies. Our discovery that red blood cells (RBCs) sequester mitochondrial DNA opens a new avenue for detecting circulating nucleic acids, as RBCs represent an unrecognized reservoir of circulating nucleic acid. Here, we show that RBCs acquire tumor DNA following coculture with lung cancer cell lines harboring Kirsten rat sarcoma viral oncogene homolog (KRAS) and epidermal growth factor receptor (EGFR) mutations. RBC-bound tumor DNA is detectable in patients with early-stage non-small cell lung cancer (NSCLC) but not in healthy controls by qPCR. Our results collectively uncover a previously unrecognized yet easily accessible reservoir of tumor DNA, offering a promising foundation for future RBC-based tumor diagnostics.NEW & NOTEWORTHY We present a novel method for lung cancer detection by revealing RBCs as a reservoir for tumor DNA, overcoming the limitations of current circulating tumor ctDNA methodologies. By demonstrating that RBCs can capture tumor DNA, including critical mutations found in lung cancer, we provide a promising, biopsy-free avenue for early cancer diagnostics. This discovery opens up exciting possibilities for developing RBC-based diagnostic tools, significantly enhancing the sensitivity and clinical utility of noninvasive cancer detection.

Liquid biopsy in lung cancer

Lung cancer is a highly prevalent malignancy worldwide and the primary cause of mortality. The absence of systematic and standardized diagnostic approaches for identifying potential pulmonary nodules, early-stage cancers, and indeterminate tumors has led clinicians to consider tissue biopsy and pathological sections as the preferred method for clinical diagnosis, often regarded as the gold standard. The conventional tissue biopsy is an invasive procedure that does not adequately capture the diverse characteristics and evolving nature of tumors. Recently, the concept of 'liquid biopsy' has gained considerable attention as a promising solution. Liquid biopsy is a non-invasive approach that facilitates repeated analysis, enabling real-time monitoring of tumor recurrence, metastasis, and response to treatment. Currently, liquid biopsy includes circulating tumor cells, circulating cell-free DNA, circulating tumor DNA, circulating cell-free RNA, extracellular vesicles, and other proteins and metabolites. With rapid progress in molecular technology, liquid biopsy has emerged as a highly promising and intriguing approach, yielding compelling results. This article critically examines the significant role and potential clinical implications of liquid biopsy in the diagnosis, treatment, and prognosis of lung cancer.

MicroRNA Profiling of Red Blood Cells for Lung Cancer Diagnosis

BACKGROUND

Despite extensive endeavors to establish cell-free circulating biomarkers for lung cancer diagnosis, clinical adoption remains elusive. Noteworthy, emergent evidence suggests the pivotal roles of red blood cells (RBCs) and their derivatives in tumorigenesis, illuminating potential avenues for diagnostic advancements using blood cell-derived microRNAs (miRNAs).

METHODS

We executed microarray analyses on three principal blood cell types-RBCs, peripheral blood mononuclear cells (PBMCs), and neutrophils-encompassing 26 lung cancer patients and 26 healthy controls. Validation was performed using droplet digital PCR within an additional cohort comprising 42 lung cancer and 39 control cases.

RESULTS

Our investigation unearthed distinct miRNA profiles associated with lung cancer across all examined blood cell types. Intriguingly, RBC-miRNAs emerged as potential novel biomarkers for lung cancer, an observation yet to be documented. Importantly, integrating miRNAs from disparate blood cell types yielded a superior diagnostic accuracy for lung cancer over individual cell-type miRNAs. Subsequently, we formulated three diagnostic panels, adeptly discerning non-small cell lung cancer, adenocarcinoma, and squamous cell carcinoma, maintaining consistency across various disease stages.

CONCLUSION

RBC-derived molecules introduce novel cancer biomarkers, and exploiting miRNA profiles across varied blood cell types unveils a promising frontier for lung cancer's early detection and histological classification.