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. 2021 Jul 8;30(23):2263–2271. doi: 10.1093/hmg/ddab187

The SWI/SNF complex regulates the expression of miR-222, a tumor suppressor microRNA in lung adenocarcinoma

Paola Peinado 1,2, Alvaro Andrades 3,4, Jordi Martorell-Marugán 5, Jeffrey R Haswell 6, Frank J Slack 7,8, Pedro Carmona-Sáez 9,10, Pedro P Medina 11,12,13,✉
PMCID: PMC9989735  PMID: 34240140

Abstract

SWitch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes are key epigenetic regulators that are recurrently mutated in cancer. Most studies of these complexes are focused on their role in regulating protein-coding genes. However, here, we show that SWI/SNF complexes control the expression of microRNAs. We used a SMARCA4-deficient model of lung adenocarcinoma (LUAD) to track changes in the miRNome upon SMARCA4 restoration. We found that SMARCA4-SWI/SNF complexes induced significant changes in the expression of cancer-related microRNAs. The most significantly dysregulated microRNA was miR-222, whose expression was promoted by SMARCA4-SWI/SNF complexes, but not by SMARCA2-SWI/SNF complexes via their direct binding to a miR-222 enhancer region. Importantly, miR-222 expression decreased cell viability, phenocopying the tumor suppressor role of SMARCA4-SWI/SNF complexes in LUAD. Finally, we showed that the miR-222 enhancer region resides in a topologically associating domain that does not contain any cancer-related protein-coding genes, suggesting that miR-222 may be involved in exerting the tumor suppressor role of SMARCA4. Overall, this study highlights the relevant role of the SWI/SNF complex in regulating the non-coding genome, opening new insights into the pathogenesis of LUAD.

Introduction

Gene expression regulation is essential for an adequate execution of all biological processes and alterations in these regulatory mechanisms can lead to tumor formation and progression. Indeed, the loss of epigenetic control of gene expression is a key hallmark of cancer (1). Among all epigenetic changes, chromatin remodeling has spurred great interest in the field. Several studies have shown that the SWitch/Sucrose Non-Fermentable (SWI/SNF) complex, a member of the family of ATP-dependent chromatin remodeling complexes, is mutated in nearly 25% of all cancers (2–4). In fact, SWI/SNF is one of the most frequently mutated epigenetic regulators in cancer (5).

Different SWI/SNF complexes, defined by their subunit composition, can exist or coexist depending on the cell type and the cellular context. These SWI/SNF complexes are composed of an ATPase, which can be either SMARCA4 (also known as BRG1) or SMARCA2 (BRM), and up to 15 associated subunits encoded by 29 genes (6). Specifically, SMARCA4 is the most mutated SWI/SNF gene in lung adenocarcinoma (LUAD), and it is a driver gene in this type of tumor (1,7,8). The mutation rate of SMARCA4 can reach 42% in LUAD cell lines (9,10) and over 10% in primary LUAD tumors (manuscript in preparation). Moreover, SMARCA4 modulates the expression of key genes related to lung cancer development (11–15). Recently, SMARCA4 restoration in a SMARCA4-deficient model in LUAD was found to increase chromatin accessibility and reactivate genes involved in epithelial cell differentiation, regulation of cell morphogenesis and development (16). However, although the SWI/SNF complex has a genome-wide regulatory activity, most studies so far have focused on the regulation of protein-coding genes, neglecting the regulation of non-protein-coding genes.

One component of the non-coding genome corresponds to microRNAs (miRNAs). They are small RNAs of 18–25 nucleotides that bind to target messenger RNAs and promote either their degradation or their translational repression (17). Moreover, miRNA expression is altered in cancer, and this dysregulation is closely related to tumor development and progression (18–20).

In this study, we tested the hypothesis that SMARCA4 can also exert its tumor suppressor function through the regulation of the expression of miRNAs that are involved in tumor development. We found that the SWI/SNF complex, when SMARCA4 is the catalytic subunit, modulated the expression of miR-222 through direct binding to its enhancer. Furthermore, we demonstrated that overexpression of miR-222 phenocopied the tumor suppressor effect of SMARCA4 in LUAD. Our results highlight the importance of considering miRNAs as another layer of regulation that can be controlled by the SWI/SNF complex and that plays a relevant role in pathogenesis.

Results

SMARCA4 restoration induces expression changes in cancer-related miRNAs that could contribute to its tumor suppressor role

To analyze the specific involvement of SMARCA4 in regulating miRNA expression in LUAD, we chose an in vitro model that was SMARCA4 deficient so that we could track the changes derived from its re-expression. We used the A549 cell line because it has a homozygous frameshift deletion in SMARCA4 that generates a premature stop codon (10). Our previous studies have also shown that this cell line has no residual SMARCA4 protein and that the ATPase activity of the SWI/SNF relies on SMARCA2 (9). We restored SMARCA4 in this cellular model using a transient transfection of a DNA construct containing the most abundant isoform of this gene in lung tissue (see Materials and Methods). We corroborated that SMARCA4 was re-expressed, reaching its peak expression at 24 h (Supplementary Material, Fig. S1A) and that it was located in the chromatin fraction of the transfected cells (Supplementary Material, Fig. S1B). To determine whether the exogenous SMARCA4 was incorporated in the endogenous SWI/SNF complexes of the A549 cell line, we performed two complementary immunoprecipitation analyses (Supplementary Material, Fig. S1C). When we pulled down SMARCC1, one of the core SWI/SNF subunits (21), we observed that our exogenous SMARCA4 was bound to it. The same interaction was obtained when we performed the opposite pull-down. This result showed that the exogenous SMARCA4 was successfully incorporated into endogenous SWI/SNF complexes, yielding complexes where SMARCA4 was the catalytic subunit. We also confirmed by immunoprecipitation assays that SMARCA2-containing SWI/SNF complexes coexisted with the new SMARCA4-SWI/SNF complexes in the transfected A549 cells (Supplementary Material, Fig. S1D).

The tumor suppressor role of SMARCA4 was validated by measuring cell viability and colony formation after its restoration. Ectopic expression of SMARCA4 impaired cell viability up to 48% after 4 days of transfection (Fig. 1A) and reduced the clonogenic capacity by 49% (Fig. 1B). Both results agreed with the tumor suppressor function of this protein and showed that transient restoration of SMARCA4 decreased the viability of LUAD cells.

Figure 1 .

Figure 1

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SMARCA4 restoration in A549 cells reduces cell viability and changes the miRNome. (A) Resazurin assay at different time points after transfection of A549 with empty vector (EV) or the SMARCA4 plasmid (SMARCA4). (B) Clonogenic assay after 14 days of SMARCA4 restoration in A549. Upper panel: Colony number quantification; lower panel: Representative images of each condition after the staining with crystal violet. (C) Volcano plot with the differentially expressed miRNAs upon SMARCA4 restoration. miRNAs with a FDR <0.05 and an absolute log2 FC >1 are displayed with a diamond (NS, non-significant; FDR, false discovery rate; FC, fold change). (D) Top three significantly enriched pathways of the dysregulated miRNAs upon SMARCA4 restoration. For each pathway, we represented the number of genes that are targets of at least seven miRNAs of our dysregulated miRNAs. (E) miR-222 relative expression levels after 24 and 48 h of restoration of SMARCA4 in A549. Values represent mean ± SD (n ≥ 3). *Two-tailed t-test P < 0.05; **P < 0.01; ***P < 0.001.

Following demonstration that SMARCA4 re-expression showed tumor suppressor activity, we determined whether changes in the miRNome could contribute to its tumor suppressor role. For this purpose, we performed miRNA sequencing after 48 h of SMARCA4 re-expression. We found 57 miRNAs that were significantly dysregulated upon SMARCA4 restoration (false discovery rate <0.05, absolute log2 fold change >1). Specifically, 29 miRNAs showed increased levels and 28 miRNAs were downregulated in A549 transfected with SMARCA4 compared with A549 transfected with an empty vector (Fig. 1C and Supplementary Material, Fig. S2A).

We used the online tool DIANA-miRPath (Supplementary Material S1) to analyze the pathways that could be altered by the differentially expressed miRNAs, and we observed that for both upregulated and downregulated miRNAs, the most significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was ‘MicroRNAs and cancer’ followed by ‘Transcriptional misregulation in cancer’ in the case of the downregulated miRNAs (Fig. 1D and Supplementary Material, Fig. S2B). These findings suggested that re-expression of SMARCA4 not only regulates protein-coding genes as it has been previously described (11,13,14,16), but also changes the expression of key miRNAs involved in tumorigenic pathways.

SMARCA4 binds to an enhancer of miR-222 and controls its expression

Among the cancer-related miRNAs that were differentially expressed upon SMARCA4 restoration, we selected the most significant dysregulated miRNA, miR-222, to perform a detailed study. First, we confirmed by real-time quantitative polymerase chain reaction that miR-222 levels increased 24 h after SMARCA4 restoration, and at 48 h, they decreased along with SMARCA4 levels (Fig. 1E).

The decrease in miR-222 expression after 48 h of SMARCA4 restoration agreed with the miRNA-Seq data, which showed that it was the top downregulated miRNA at that time point (Fig. 1C).

We noticed that the MIR222 locus is contained within an enhancer according to the GeneHancer database (GeneHancer ID: GH0XJ045746) (22). Enhancers are frequently targeted by the SWI/SNF complex (16,23–30). Therefore, we hypothesized that miR-222 may be regulated by the enhancer under the control of the SWI/SNF complex. Using public chromatin immunoprecipitation sequencing (ChIP-Seq) data from A549 (31), we confirmed that the region upstream of miR-222 contains peaks of H3K4me1 and H3K27ac marks, which are characteristic of enhancers (Fig. 2A, Supplementary Material S1).

Figure 2 .

Figure 2

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SMARCA4 binds to the enhancer of miR-222 in a time-dependent manner. (A) Overview of the miR-222 genomic context including ChIP-Seq profiles of H3K4me3, H3K27ac and H3K4me1 in the A549 cell line (Supplementary Material S1). High levels of H3K27ac and H3K4me1 and low levels of H3K4me3 are characteristic of enhancer regions. (B) Analysis by ChIP-qPCR of SMARCA4 or SMARCA2 binding to the enhancer of miR-222 after 24 and 48 h of SMARCA4 restoration in A549. (C) Quantification of SMARCA4 protein levels relative to ACTB expression in transfected A549 cells after 24 and 48 h of SMARCA4 restoration. Values represent mean ± SD (n ≥ 3). *Two-tailed t-test P < 0.05; **P < 0.01.

To determine whether SMARCA4- or SMARCA2-containing SWI/SNF complexes bind to the miR-222 enhancer, we performed ChIP-quantitative polymerase chain reaction (ChIP-qPCR) analyses. After 24 h of restoration of SMARCA4, we obtained a significant enrichment only of SMARCA4 signal at the miR-222 enhancer (Fig. 2B). However, after 48 h, as SMARCA4 transient expression declined, it was replaced by SMARCA2. This turnaround also matched the expression changes that we found in miR-222 (Fig. 1E). These data showed that the expression of miR-222 was directly influenced by SMARCA4, which reached its peak expression 24 h after transfection (Fig. 2C). These results suggest a model where miR-222 expression is activated preferentially by SMARCA4-SWI/SNF complexes and not by SMARCA2-SWI/SNF complexes (Fig. 3).

Figure 3 .

Figure 3

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Schematic overview of the regulation of miR-222 by the SWI/SNF complex. Upper panel: After 24 h of SMARCA4 re-expression in A549 cells, there are high levels of SMARCA4 and it is included in the SWI/SNF complex. There is a predominance of SWI/SNF complexes with SMARCA4 and this type of complexes induces miR-222 expression. Lower panel: After longer times of transfection, SMARCA4 levels in A549 decrease, and SWI/SNF complexes with SMARCA2 are predominant. This complex impairs miR-222 expression. Both figures were made using BioRender (https://app.biorender.com/).

miR-222 impairs cell viability phenocopying SMARCA4 restoration in A549

Since the levels of miR-222 strongly increased upon SMARCA4 restoration, we aimed to elucidate the phenotypic effects of this miRNA in the A549 cell line. We transfected A549 cells with either a miR-222 mimic or a negative control mimic. Interestingly, we found that increasing the levels of miR-222 (Fig. 4A) decreased cell viability by more than half (50.2%) after 7 days of transfection (Fig. 4B). Moreover, miR-222 overexpression also impaired cell clonogenicity by 44%, pointing to a tumor suppressor role in this LUAD cell line (Fig. 4C). Interestingly, we found that increasing miR-222 levels resulted in the same phenotype as restoring SMARCA4 in A549. These data highlight that SMARCA4-mutant contexts not only change key protein-coding genes needed by the cancer cell but also modify the expression of miRNAs that have relevant functions in tumor progression.

Figure 4 .

Figure 4

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miR-222 behaves as a tumor suppressor miRNA by decreasing cell viability and colony formation. (A) Relative miR-222 expression levels after transfection of A549 cells with either a negative control mimic or a miR-222 mimic. (B) Resazurin assay at different time points after transfection of A549 with negative control mimic or miR-222 mimic. (C) Clonogenic assay after 14 days of transfection of A549 with negative control mimic or miR-222 mimic. Left: Colony number quantification. Right: Representative images of each condition after the staining with crystal violet. Values represent mean ± SD (n ≥ 3). *Two-tailed t-test P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.

The miR-222 enhancer belongs to a topologically associating domain that does not contain cancer-related protein-coding genes

We observed that SMARCA4-SWI/SNF complex binds to the miR-222 enhancer, increasing the expression of miR-222, and that miR-222 overexpression phenocopies SMARCA4 restoration in A549. However, we wondered whether the miR-222 enhancer modulates cancer-related protein-coding genes that might contribute to the phenotype. To determine potential protein-coding targets of the miR-222 enhancer, we studied the three-dimensional organization and interactions of the enhancer region in lung cells. We queried high-throughput chromosome conformation capture (Hi-C) and chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) data from encyclopedia of DNA elements (ENCODE, https://www.encodeproject.org, v111). We found Hi-C and CTCF ChIA-PET data for A549 and for the normal lung fibroblast cell line IMR-90 (Supplementary Material S1). In both cell lines, the miR-222 enhancer belonged to a topologically associating domain (TAD) that was delimited by CCCTC-Binding Factor (CTCF)-binding sites (Supplementary Fig. S3). The TADs were more well-defined in IMR-90 than in A549 due to a better resolution (5 kb for IMR-90, 40 kb for A549). The smaller TAD that contained the enhancer in IMR-90 did not encompass any protein-coding genes. In A549, the TAD was larger due to the poorer resolution, and it only contained the protein-coding gene KRBOX4 but, to our knowledge, KRBOX4 has not been linked to cancer. The nearest cancer genes were KDM6A and RBM10, but they belonged to different TADs, suggesting that the miR-222 enhancer does not interact physically with these genes despite their proximity in the genomic sequence. Overall, we found no evidence that the miR-222 enhancer modulates any well-known cancer-related protein-coding genes, supporting that its tumor suppressor function may rely on miR-222.

Discussion

The implications of the SWI/SNF complex in chromatin regulation have been experimentally corroborated in several biological contexts (12–14,24,25,27,32–35). Many of these studies have also shown that aberrant SWI/SNF complexes, due to genetic alterations or loss of expression of some of their subunits, have a pronounced effect on the transcriptome of the cells and therefore on tumorigenesis too. However, those analyses have been focused on protein-coding genes without evaluating the impact on non-protein-coding genes. Here, we show that re-expression of SMARCA4 in a LUAD SMARCA4-deficient cell line affects other master regulators: miRNAs. This connection of the SWI/SNF complex and the miRNome is supported by the fact that miRNA biogenesis is controlled by epigenetic mechanisms, such as methylation and histone modification, that are also associated with chromatin remodeling (36–38).

We observed that SMARCA4 restoration in A549 cells induced significant changes in the miRNome and many of those miRNAs were associated with tumor development. The most significant dysregulated miRNA was miR-222. This miRNA is dysregulated in many different tumor types [reviewed in (39,40)]. However, the role of miR-222 is controversial. Some studies have shown that miR-222 has oncogenic properties and that it is upregulated in tumors (41–44), but in other types of cancer, it shows a tumor suppressor role (45–47). Moreover, this contradictory role has been observed even within lung cancer (48).

In our LUAD model, overexpression of miR-222 impaired cell viability and clonogenicity. Interestingly, this phenotype resembled SMARCA4 restoration. An analogous result was obtained in a zebrafish model where SMARCA4 loss phenocopied the silencing of DICER, one of the key enzymes involved in miRNA biogenesis (49). However, the SWI/SNF complex has a genome-wide regulatory activity of gene expression and other target genes aside from miR-222 could also contribute to the tumor suppressor role of SMARCA4 (11–15).

Here, we have observed for the first time that the SWI/SNF complex modulates miR-222 by binding to its enhancer region. Although the SWI/SNF complex can bind to promoters, it is also well known that it can regulate gene expression through enhancers (16,23–30). Moreover, recent work has shown that SMARCA4 restoration increases enhancer-associated histone marks, supporting the relevance of the SWI/SNF complex at these specific regulatory regions (16).

Interestingly, we only observed the upregulation of miR-222 when SMARCA4 levels were at their peak of expression, but when SMARCA4 levels decreased, the binding was replaced by SMARCA2. This change of ATPase subunit of the SWI/SNF complex had the opposite effect on miR-222 expression. This abrupt change in expression is supported by a recent study that has also highlighted the dynamism of the SWI/SNF complex in regulating chromatin accessibility and how alterations in this complex can affect chromatin within minutes (35).

Previous studies have suggested complementary roles for SMARCA2 and SMARCA4 (50,51), but it has been shown that in SMARCA4-mutant contexts, SMARCA2 acquires distinct roles during the oncogenic transformation and becomes an essential gene (52). This observation coincides with our result and suggests that the downregulation of miR-222 after the decrease of wild-type SMARCA4 could be the consequence of SMARCA2 acting as a part of a residual SWI/SNF complex in a SMARCA4-mutant context. It is known that in SWI/SNF-mutant cancers, SWI/SNF function is perturbed rather than abrogated in tumor cells, thanks to the activity of residual SWI/SNF complexes (53). Those residual complexes have attracted great interest from the field of synthetic lethal therapies directed to SWI/SNF-mutant cancers [reviewed in (4,54)].

Overall, we report that the expression of miR-222 is under control of the SWI/SNF complex and shows different expression patterns depending on the composition of the catalytic subunit of the complex, suggesting a change derived from the transformation of SMARCA2 to an essential gene in SMARCA4-mutant LUADs.

Materials and Methods

Cell culture

LUAD cell line A549 was purchased from the American Type Culture Collection, and it was tested to be free of mycoplasma contamination. It was grown under standard conditions (humidified 5% CO2 atmosphere at 37°C) in Dulbecco’s-modified Eagle’s medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin/amphotericin.

Transfections

For restoration of SMARCA4, a plasmid encoding the isoform E, which is the most abundant isoform of SMARCA4 in lung, was obtained from Romero et al. (13). The transfections were performed with Lipofectamine 2000 (Thermo Scientific, Waltham, MA, USA). Negative control miRNA mimic (mirVana® miRNA mimic Negative Control # 4464058) and miR-222 mimic (mirVana® miRNA mimic #4464066) were purchased from Thermo Scientific and were transfected with Lipofectamine RNAimax (Thermo Scientific) following the manufacturer’s instructions. All transfections were performed using OptiMEM as a reduced serum medium.

miRNA library preparation and sequencing

Total RNA from three biological replicates of transfected A549 cells was extracted using the mirVana RNA Isolation Kit (Thermo Scientific). RNA concentration and quality were analyzed by NanoDrop 2000 and Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA, USA), respectively. Illumina TruSeq® Small RNA Library Prep Kit (Illumina Inc., San Diego, CA, USA) was used to generate sequencing libraries, according to the manufacturer’s instructions. One microgram of RNA was used as input for library preparation. RNA samples were barcoded to allow pooling of samples and they were size-selected using acrylamide gel electrophoresis. Sequencing was carried out on a NextSeq 500 System using a NextSeq 500/550 High-Output Kit v2.5 (75 cycles), obtaining an average of 3 million reads per sample. Data analysis is described in Supplementary Material S1.

ChIP-qPCR

ChIP assays for SMARCA4 and SMARCA2 were performed following the protocol of Asenjo et al. (55) with minor modifications. Two million transfected A549 cells at different time points for each condition were used for this protocol. Bioruptor® Sonicator (Diagenode, Seraing, Belgium) was set to sonicate the cells for 35 cycles 45 s ON, 15 s OFF. One microgram of the antibody of SMARCA4 (ab11064, Abcam, Cambridge, UK) or a 1:100 dilution of the antibody of SMARCA2 (#11966, Cell Signaling Technology, Danvers, MA, USA) were used per million of cells for immunoprecipitation. For each condition, a control of non-specific binding (anti-IgG-mouse, #12-371, Merck KGaA, Darmstadt, Germany; anti-IgG-rabbit, #12-370, Merck KGaA) was included at the same amounts as the SMARCA4 or SMARCA2 antibodies. Eluted DNA was quantified with a Qubit™ dsDNA High-Sensitivity Assay Kit (Thermo Scientific); 0.1 ng of DNA were used for measuring absolute levels of binding to the enhancer of miR-222 by qPCR. The reactions were performed using a KAPA SYBR® FAST qPCR Master Mix (Merck) in a QuantStudio™ 3 system (Thermo Scientific) following manufacturer’s instructions. Fold enrichment was calculated relative to IgG controls. The primer sequences are detailed in Supplementary Table S1.

Resazurin assay

Cell viability was measured by resazurin assays at different time points after transfection of A549. Cells were treated with a final concentration of 0.12 mM resazurin sodium salt (Sigma Aldrich, Merck KGaA) and incubated for 4 h prior to the addition of 3% sodium dodecyl sulfate. Fluorescence was measured in a Glomax® Discover Multimode Microplate Reader (Promega, Madison, WI, USA) (excitation fluorescence 520 nm and emission fluorescence 580–640 nm).

Colony assay

Clonogenicity was evaluated by seeding 1000 cells of transfected A549 cells per well in six-well plates. After 14 days, colonies were stained for 15 min with a solution of 0.1% crystal violet, 1% formaldehyde, 1% methanol, phosphate-buffered saline (PBS) and H2O. Then, the plates were rinsed with tap water and dried.

Statistical analysis

Normality of the data was addressed by the Shapiro–Wilk test. Two-tailed Student’s t-tests were applied for normally distributed data. Differences were considered significant at P-value <0.05. Results were expressed as mean ± standard deviation of at least three different biological replicates.

Supplementary Material

HMG-2021-D-00264-PEINADO-SUPPLEMENTARY_ddab187
Click here for additional data file. (6.5MB, zip)

Acknowledgement

The authors thank the PhD program in Biochemistry and Molecular Biology of the University of Granada.

Conflict of Interest Statement. None declared.

Contributor Information

Paola Peinado, Department of Biochemistry and Molecular Biology I, University of Granada, Granada 18071, Spain; GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain.

Alvaro Andrades, Department of Biochemistry and Molecular Biology I, University of Granada, Granada 18071, Spain; GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain.

Jordi Martorell-Marugán, GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain.

Jeffrey R Haswell, Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.

Frank J Slack, Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Harvard Medical School Initiative for RNA Medicine, Boston, MA 02215, USA.

Pedro Carmona-Sáez, GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Department of Statistics, University of Granada, Granada 18071, Spain.

Pedro P Medina, Department of Biochemistry and Molecular Biology I, University of Granada, Granada 18071, Spain; GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Health Research Institute of Granada (ibs.Granada), Granada 18012, Spain.

Funding

P.P.M.’s laboratory is funded by the Ministry of Economy of Spain (SAF2015-67919-R); Junta de Andalucía (PY20-00688, PI-0135-2020, PIGE-0213-2020); International Association for the Study of Lung Cancer; Spanish Association for Cancer Research (LAB-AECC-2018). The PhD ‘La Caixa Foundation’ (LCF/BQ/DE15/10360019) Fellowship (to P.P.). The FPU (FPU17/00067) Fellowship (to A.A.).

Data availability

Raw and processed miRNA-Seq data is publicly available at the GEO repository (GSE167140).

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

HMG-2021-D-00264-PEINADO-SUPPLEMENTARY_ddab187
Click here for additional data file. (6.5MB, zip)

Data Availability Statement

Raw and processed miRNA-Seq data is publicly available at the GEO repository (GSE167140).

Articles from Human Molecular Genetics are provided here courtesy of Oxford University Press

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