Treatment for non-small-cell lung cancer and circulating tumor cells

Early circulating tumor DNA dynamics at the commencement of curative-intent radiotherapy or chemoradiotherapy for NSCLC

Background

The kinetics of circulating tumor DNA (ctDNA) release following commencement of radiotherapy or chemoradiotherapy may reflect early tumour cell killing. We hypothesised that an increase in ctDNA may be observed after the first fraction of radiotherapy and that this could have clinical significance.

Materials and methods

ctDNA analysis was performed as part of a prospective, observational clinical biomarker study of non-small cell lung cancer (NSCLC) patients, treated with curative-intent radiotherapy or chemoradiotherapy. Blood was collected at predefined intervals before, during (including 24 h after fraction 1 of radiotherapy) and after radiotherapy/chemoradiotherapy. Mutation-specific droplet digital PCR assays used to track ctDNA levels during and after treatment.

Results

Sequential ctDNA results are available for 14 patients with known tumor-based mutations, including in EGFR, KRAS and TP53, with a median follow-up of 723 days (range 152 to 1110). Treatments delivered were fractionated radiotherapy/chemoradiotherapy, in 2-2.75 Gy fractions (n = 12), or stereotactic ablative body radiotherapy (SABR, n = 2). An increase in ctDNA was observed after fraction 1 in 3/12 patients treated with fractionated radiotherapy with a complete set of results, including in 2 cases where ctDNA was initially undetectable. Neither SABR patient had detectable ctDNA immediately before or after radiotherapy, but one of these later relapsed systemically with a high detected ctDNA concentration.

Conclusions

A rapid increase in ctDNA levels was observed after one fraction of fractionated radiotherapy in three cases. Further molecular characterization will be required to understand if a "spike" in ctDNA levels could represent rapid initial tumor cell destruction and could have clinical value as a surrogate for early treatment response and/or as a means of enriching ctDNA for mutational profiling.

CircRNA B cell linker regulates cisplatin sensitivity in nonsmall cell lung cancer via microRNA-25-3p/BarH‑like homeobox 2 axis

Cisplatin (DDP) was a commonly used drug in the treatment of nonsmall cell lung cancer (NSCLC). However, the current resistance of patients to DDP seriously affected its therapeutic effect. Circular RNAs (circRNAs) have been reported to regulate drug resistance in cells. The purpose of this paper is to study the effect of circRNA B cell linker (circ_BLNK) in DDP resistance of NSCLC. The abundances of circ_BLNK, microRNA-25-3p (miR-25-3p) and BarH‑like homeobox 2 (BARX2) were examined by quantitative real-time PCR and western blot analysis. Cell proliferation and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, EdU assay and flow cytometry. Transwell assay was applied to assess cell migration and invasion. Protein levels were quantified by western blot analysis. Dual-luciferase reporter assay was enforced to confirm the links among circ_BLNK, miR-25-3p and BARX2. The mice models were enforced to evaluate tumorigenicity. Herein, circ_BLNK and BARX2 were lower-expressed, whereas miR-25-3p was higher-expressed in A549/DDP and H1299/DDP cells than their homologous parental NSCLC cells. Circ_BLNK increases improved DDP sensitivity of NSCLC cells by promoting cell apoptosis and inhibiting proliferation, migration and invasion. Moreover, we confirmed that circ_BLNK regulated BARX2 by inhibiting miR-25-3p. Accordingly, overexpression of circ_BLNK improved DDP sensitivity of NSCLC cells via miR-25-3p/BARX2 axis. Besides, circ_BLNK reduced cell resistance to DDP, thereby inhibiting tumor development in mice. Circ_BLNK promoted the DDP sensitivity of NSCLC via regulating miR-25-3p/BARX2 axis.

Artificial intelligence-based classification of peripheral blood nucleated cells using label-free imaging flow cytometry

Label-free image identification of circulating rare cells, such as circulating tumor cells within peripheral blood nucleated cells (PBNCs), the vast majority of which are white blood cells (WBCs), remains challenging. We previously described developing label-free image cytometry for classifying live cells using computer vision technology for pattern recognition, based on the subcellular structure of the quantitative phase microscopy images. We applied our image recognition methods to cells flowing in a flow cytometer microfluidic channel, and differentiated WBCs from cancer cell lines (area under receiver operating characteristic curve = 0.957). We then applied this method to healthy volunteers' and advanced cancer patients' blood samples and found that the non-WBC fraction rates (NWBC-FRs), defined as the percentage of cells classified as non-WBCs of the total PBNCs, were significantly higher in cancer patients than in healthy volunteers. Furthermore, we monitored NWBC-FRs over the therapeutic courses in cancer patients, which revealed the potential ability in monitoring the clinical status during therapy. Our image recognition system has the potential to provide a morphological diagnostic tool for circulating rare cells as non-WBC fractions.

CircFBXW8 Acts an Oncogenic Role in the Malignant Progression of Non-small Cell Lung Carcinoma by miR-370-3p-Dependent Regulation of TRIM44

Non-small cell lung carcinoma (NSCLC) is an aggressive malignant tumor. Growing evidences have revealed that circular RNA (circRNA) is involved in NSCLC progression. This study aims to investigate the role of circular RNA F-box and WD repeat domain containing 8 (circFBXW8) in NSCLC progression and the underlying mechanism. The expression of circFBXW8, microRNA-370-3p (miR-370-3p) and tripartite motif containing 44 (TRIM44) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was detected by western blot analysis or immunohistochemistry assay. Additionally, cell viability, colony-forming ability, proliferation and apoptosis were investigated by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide, cell colony formation, 5-Ethynyl-29-deoxyuridine and flow cytometry analysis assays, respectively. Cell migratory and invasive abilities were examined by wound-healing and transwell assays. The regulatory relationship between miR-370-3p and circFBXW8 or TRIM44 was identified by dual-luciferase reporter and RNA pull-down assays. Furthermore, xenograft experiment was employed to explain the effect of circFBXW8 silencing on tumor formation. CircFBXW8 and TRIM44 expression were upregulated, while miR-370-3p was downregulated in NSCLC tissues, cells and the exosomes from NSCLC cells compared with respective controls. CircFBXW8 depletion repressed NSCLC cell proliferation, migration and invasion, but promoted cell apoptosis. CircFBXW8 acted as a sponge of miR-370-3p and regulated NSCLC cell malignancy by binding to miR-370-3p. Additionally, miR-370-3p repressed NSCLC cell processes by regulating TRIM44. CircFBXW8 knockdown inhibited tumor formation in vivo. Further, circFBXW8 secretion was mediated by exosomes. CircFBXW8 modulated NSCLC progression by increasing TRIM44 expression through sponging miR-370-3p, which provided a new direction for studying the therapy of NSCLC.

Imaging Biomarkers of Tumour Proliferation and Invasion for Personalised Lung Cancer Therapy

Personalised treatment in oncology has seen great developments over the last decade, due to both technological advances and more in-depth knowledge of radiobiological processes occurring in tumours. Lung cancer therapy is no exception, as new molecular targets have been identified to further increase treatment specificity and sensitivity. Yet, tumour resistance to treatment is still one of the main reasons for treatment failure. This is due to a number of factors, among which tumour proliferation, the presence of cancer stem cells and the metastatic potential of the primary tumour are key features that require better controlling to further improve cancer management in general, and lung cancer treatment in particular. Imaging biomarkers play a key role in the identification of biological particularities within tumours and therefore are an important component of treatment personalisation in radiotherapy. Imaging techniques such as PET, SPECT, MRI that employ tumour-specific biomarkers already play a critical role in patient stratification towards individualized treatment. The aim of the current paper is to describe the radiobiological challenges of lung cancer treatment in relation to the latest imaging biomarkers that can aid in the identification of hostile cellular features for further treatment adaptation and tailoring to the individual patient’s needs.

Detection of EGFR Mutations in cfDNA and CTCs, and Comparison to Tumor Tissue in Non-Small-Cell-Lung-Cancer (NSCLC) Patients

Lung cancer is the leading cause of cancer-related mortality worldwide. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapies, based on the evaluation of EGFR mutations, have shown dramatic clinical benefits. EGFR mutation assays are mainly performed on tumor biopsies, which carry risks, are not always successful and give results relevant to the timepoint of the assay. To detect secondary EGFR mutations, which cause resistance to 1st and 2nd generation TKIs and lead to the administration of a 3rd generation drug, effective and non-invasive monitoring of EGFR mutation status is needed. Liquid biopsy analytes, such as circulating tumor cells (CTCs) and circulating tumor DNA (cfDNA), allow such monitoring over the course of the therapy. The aim of this study was to develop and optimize a workflow for the evaluation of cfDNA and CTCs in NSCLC patients all from one blood sample. Using Vortex technology and EntroGen ctEGFR assay, EGFR mutations were identified at 0.5 ng of DNA (∼83 cells), with a sensitivity ranging from 0.1 to 2.0% for a total DNA varying from 25 ng (∼4 CTCs among 4000 white blood cells, WBCs) to 1 ng (∼4 CTCs among 200 WBCs). The processing of plasma-depleted-blood provided comparable capture recovery as whole blood, confirming the possibility of a multimodality liquid biopsy analysis (cfDNA and CTC DNA) from a single tube of blood. Different anticoagulants were evaluated and compared in terms of respective performance. Blood samples from 24 NSCLC patients and 6 age-matched healthy donors were analyzed with this combined workflow to minimize blood volume needed and sample-to-sample bias, and the EGFR mutation profile detected from CTCs and cfDNA was compared to matched tumor tissues. Despite the limited size of the patient cohort, results from this non-invasive EGFR mutation analysis are encouraging and this combined workflow represents a valuable means for informing therapy selection and for monitoring treatment of patients with NSCLC.

Knockdown of circPRKCA Restrained Cell Growth, Migration, and Invasion of NSCLC Cells Both in vitro and in vivo via Regulating miR-330-5p/PDK1/AKT Pathway

Background

Protein kinase Cα (PRKCA) is an oncogene in multiple cancers including non-small-cell lung cancer (NSCLC) and can be transcribed into a number of circular PRKCAs (circPRKCAs). Here, we aimed to elaborate the role and mechanism of circPRKCA_024 (circPRKCA) in malignant progression of NSCLC.

Methods

Expression of circPRKCA, miRNA (miR)-330-5p and 3-phosphoinositide-dependent protein kinase-1 (PDK1) was measured by real-time quantitative PCR and Western blotting, and their relationship was testified by dual-luciferase reporter assay, RNA immunoprecipitation, and RNA pull-down assay. Cell behaviors were evaluated by cell counting kit (CCK)-8, flow cytometry, and transwell assays. AKT activity was confirmed by Western blotting. Xenograft experiment assessed tumor growth.

Results

Expression of circPRKCA and PDK1 was upregulated, and miR-330-5p was downregulated in NSCLC tissues and cell lines. High circPRKCA was correlated with TNM stage and lymph node metastasis of NSCLC patients. Silencing circPRKCA could suppress cell viability, migration, and invasion in A549 and H1299 cells, accompanied with apoptosis rate promotion. Moreover, circPRKCA knockdown retarded tumor growth of A549 cells in vivo. Molecularly, miR-330-5p was sponged by circPRKCA, and PDK1 was a target of miR-330-5p. Inhibiting miR-330-5p could attenuate the suppression of circPRKCA knockdown on cell growth, migration, and invasion; contrarily, promoting miR-330-5p caused inhibition on those cell behaviors by downregulating PDK1. Analogously, AKT activity was suppressed by circPRKCA downregulation and miR-330-5p upregulation in NSCLC cells both in vitro and in vivo.

Conclusion

Depleting circPRKCA inhibited PDK1 to suppress NSCLC cell malignant behaviors through miR-330-5p/PDK1/AKT pathway.

circ_0007385 served as competing endogenous RNA for miR-519d-3p to suppress malignant behaviors and cisplatin resistance of non-small cell lung cancer cells

Background

Circular RNAs (circRNAs) have been closely implicated in competing endogenous RNA (ceRNA) network among human cancers including non‐small cell lung cancer (NSCLC). However, the role of most circRNAs in NSCLC remains to be determined. Here, we aimed to investigate the role of hsa_circ_0007385 (circ_0007385) in NSCLC cells.

Methods

Expression of hsa_circ_0007385 (circ_0007385), miRNA (miR)‐519d‐5p and high‐mobility group box 1 (HMGB1) was measured by real‐time quantitative PCR and western blotting. Functional experiments were evaluated by cell counting kit (CCK)‐8, flow cytometry, fluorescein active caspase‐3 staining kit, transwell assays, western blotting, and xenograft experiment. The relationship among circ_0007385,miR‐519d‐5p and HMGB1 was testified by dual‐luciferase reporter assay. Kaplan‐Meiersurvival curve identified overall survival in NSCLC patients.

Results

circ_0007385 expression was higher in NSCLC tissues and cell lines, and was associated with poor overall survival. Silencing circ_0007385 could suppress cell proliferation, migration and invasion in A549 and H1975 cells, as well as cisplatin (DDP) resistance. Moreover, circ_0007385 silence retarded tumor growth of A549 cells in vivo. Molecularly, there was a direct interaction between miR‐519d‐3p and either circ_0007385 or HMGB1; expression of miR‐519d‐3p was downregulated in NSCLC tumors in a circ_0007385‐correlated manner, and circ_0007385 could indirectly regulate HMGB1 via miR‐519d‐3p. Functionally, both inhibiting miR‐519d‐3p and restoring HMGB1 could overturn the suppressive effect of circ_0007385 knockdown on cell proliferation, migration, invasion, and DDP resistance.

Conclusions

Collectively, circ_0007385 deletion could function anti‐tumor role in NSCLC by suppressing malignant behaviors and DDP resistance in vitro and in vivo via circ_0007385/miR‐519d‐3p/HMGB1 axis. These outcomes might enhance our understanding of the molecular mechanisms underlying the malignant progression of NSCLC.

Key points

Significant findings of the study

circ_0007385 was upregulated in NSCLC tissues and cells, and was associated with poor overall survival.

Silenced circ_0007385 suppressed NSCLC cell proliferation, migration, invasion, and DDP resistance in vitro, and tumor growth in vivo.

circ_0007385 was upregulated in NSCLC tissues and cells, and was associated with poor overall survival.

What this study adds

miR‐519d‐3p could directly interact with circ_0007385 and HMGB1 in NSCLC cells.

A promising circ_0007385/miR‐519d‐3p/HMGB1 regulatory pathway was determined in NSCLC cells.

Heparanase Inhibition by Pixatimod (PG545): Basic Aspects and Future Perspectives

Pixatimod is an inhibitor of heparanase, a protein which promotes cancer via its regulation of the extracellular environment by enzymatic cleavage of heparan sulfate (HS) and non-enzymatic signaling. Through its inhibition of heparanase and other HS-binding signaling proteins, pixatimod blocks a number of pro-cancerous processes including cell proliferation, invasion, metastasis, angiogenesis and epithelial-mesenchymal transition. Several laboratories have found that these activities have translated into potent activity using a range of different mouse cancer models, including approximately 30 xenograft and 20 syngeneic models. Analyses of biological samples from these studies have confirmed the heparanase targeting of this agent in vivo and the broad spectrum of anti-cancer effects that heparanase blockade achieves. Pixatimod has been tested in combination with a number of approved anti-cancer drugs demonstrating its clinical potential, including with gemcitabine, paclitaxel, sorafenib, platinum agents and an anti-PD-1 antibody. Clinical testing has shown pixatimod to be well tolerated as a monotherapy, and it is currently being investigated in combination with the anti-PD-1 drug nivolumab in a pancreatic cancer phase I trial.

Chemotherapy-Induced Metastasis: Molecular Mechanisms, Clinical Manifestations, Therapeutic Interventions

Chemotherapy offers long-term clinical benefits to many patients with advanced cancer. However, recent evidence has linked the cytotoxic effects of chemotherapy with the de novo elicitation of a prometastatic tumor microenvironment. This "modified" tumor microenvironment is triggered by a chemotherapy-driven cytokine storm or through direct effects of certain chemotherapeutics on stromal and/or immune cells, the most critical being tumor-associated macrophages. These chemotherapy-educated cells act as facilitators in tumor-host cell interactions promoting the establishment of distant metastasis. Certain clinical studies now offer substantial evidence that prometastatic changes are indeed identified in the tumor microenvironment of certain patient subpopulations, especially those that do not present with any pathologic response after neoadjuvant chemotherapy. Deciphering the exact contextual prerequisites for chemotherapy-driven metastasis will be paramount for designing novel mechanism-based treatments for circumventing chemotherapy-induced metastasis.

microRNA-1908-5p inhibits proliferation and promotes apoptosis by targeting PP5 in NSCLC

MicroRNA-1908 is involved in the occurrence and development of various tumors. However, the mechanism of microRNA-1908-5p in the pathogenesis of non-small cell lung cancer (NSCLC) is not thoroughly studied. Protein phosphatase 5 catalytic subunit (PP5), a member of the protein phosphatase catalytic subunit family, may be a target of the microRNA-1908-5p. In order to further explore the mechanism of microRNA-1908-5p, real-time PCR was used to detect the expression of microRNA-1908-5p in non-small cell lung cancer tissues, and analyze the relationship between the expression of microRNA-1908-5p and clinical characteristics of lung cancer patients. The target of microRNA-1908-5p was predicted by bioinformatics and verified by Dual-luciferase assay. The effects of microRNA-1908-5p on the proliferation and apoptosis of lung cancer cells were examined at the cellular level. Nude mice tumorigenesis experiment was used to study the effect of microRNA-1908-5p on cancer cells. Western blot was used to detect the expression of related proteins. The results showed that the expression of microRNA-1908-5p in lung cancer tissues was significantly lower than that in adjacent tissues. The expression of microRNA-1908-5p in the non-metastatic lung cancer tissues was significantly higher than that in the metastatic lung cancer tissues, and the expression of microRNA-1908-5p was closely related to the survival rate of patients. Bioinformatics analysis combined with double luciferase assay showed that PP5 was a significant target of microRNA-1908-5p. Our results suggest that microRNA-1908-5p can regulate the pathogenesis of NSCLC by inhibiting PP5.