Introduction
Methods
RNA-seq
Patients and clinical specimens
Cell culture
Plasmid construction, siRNA interference and lentiviral infection
RNA extraction and RT-qPCR
Nuclear and cytoplasmic extraction
RNase R/Actinomycin D
RNA fluorescence in situ hybridization
Functional experiment
CCK-8 assay
Clone formation assay
5-Ethynyl-20- deoxyuridine (EdU) assay
Wound healing assay
Transwell assay
Flow cytometry assay
Biotin-labelled RNA pull-down
Dual-luciferase assay
RNA immunoprecipitation (RIP)
Western blot analysis
Animal experiments
Immunohistochemistry (IHC)
Sanger sequencing
Statistical analysis
Results
CircNEIL3 is identified and generated from exons 8 and 9 of NEIL3 by back-splicing
CircNEIL3 promotes the proliferation, migration and invasion of PDAC cells in vitro
CircNEIL3 facilitates the tumorigenesis and metastasis of PDAC cells in vivo
CircNEIL3 functions as a sponge of miR-432-5p
MiR-432-5p reverses the oncogenic effects of circNEIL3 in PDAC cells
ADAR1 is a downstream target of miR-432-5p and is indirectly regulated by circNEIL3
CircNEIL3 promotes PDAC progression via the miR-432-5p/ADAR1 axis
ADAR1 enhances GLI1 RNA editing and functions via the cell cycle and EMT pathway
An Alu-dependent circNEIL3/miR-432-5p/ADAR1 feedback loop is correlated with PDAC prognosis
Clinicopathological features | circNEIL3 expression | P value | miR-432-5p expression | P value | ADAR1 expression | P value | |||
---|---|---|---|---|---|---|---|---|---|
High | Low | High | Low | High | Low | ||||
All cases | 52 | 52 | 52 | 52 | 52 | 52 | |||
Gender | 0.676 | 0.012* | 0.676 | ||||||
Male | 36 | 34 | 29 | 41 | 34 | 36 | |||
Female | 16 | 18 | 23 | 11 | 18 | 16 | |||
Age (year) | 0.527 | 0.527 | 0.527 | ||||||
< 60 | 18 | 15 | 18 | 15 | 15 | 18 | |||
≥ 60 | 34 | 37 | 34 | 37 | 37 | 34 | |||
Serum CA199 (U/ml) | 0.129 | 0.319 | 0.292 | ||||||
< 39 | 7 | 10 | 11 | 6 | 7 | 10 | |||
≥ 39 | 31 | 36 | 33 | 34 | 32 | 35 | |||
≥ 1000 | 14 | 6 | 8 | 12 | 13 | 7 | |||
Diameter (cm) | 0.098 | 0.033* | 0.033* | ||||||
≤ 4 | 37 | 44 | 45 | 36 | 36 | 45 | |||
> 4 | 15 | 8 | 7 | 16 | 16 | 7 | |||
Location | 0.094 | 0.403 | 0.676 | ||||||
Head | 39 | 31 | 37 | 33 | 36 | 34 | |||
Body and tail | 13 | 21 | 15 | 19 | 16 | 18 | |||
Histological grade | 0.543 | 0.311 | 0.203 | ||||||
I/ I-II | 34 | 31 | 35 | 30 | 32 | 33 | |||
II/ II-III/ III | 18 | 21 | 17 | 22 | 20 | 19 | |||
Microscopic vascular invasion | 0.02* | 0.527 | 0.833 | ||||||
Present | 41 | 30 | 34 | 37 | 35 | 36 | |||
Absent | 11 | 22 | 18 | 15 | 17 | 16 | |||
Microscopic nerve invasion | 0.014* | 0.066 | 0.22 | ||||||
Present | 50 | 42 | 49 | 43 | 48 | 44 | |||
Absent | 2 | 10 | 3 | 9 | 4 | 8 | |||
T stage | 0.168 | 0.844 | 0.554 | ||||||
T1/T2 | 25 | 32 | 29 | 28 | 27 | 30 | |||
T3/T4 | 27 | 20 | 23 | 24 | 25 | 22 | |||
N stage | 0.325 | 0.554 | 0.076 | ||||||
N0 | 21 | 26 | 22 | 25 | 28 | 19 | |||
N1/N2 | 31 | 26 | 30 | 27 | 24 | 33 | |||
M stage | 0.475 | 0.475 | 0.475 | ||||||
M0 | 50 | 52 | 52 | 50 | 50 | 52 | |||
M1 | 2 | 0 | 0 | 2 | 2 | 0 | |||
Clinical stage | 0.146 | 0.534 | 0.299 | ||||||
I-IIa | 14 | 21 | 16 | 19 | 20 | 15 | |||
IIb-IV | 38 | 31 | 36 | 33 | 32 | 37 |
Variable | Univariate analysis | Multivariate analysis | |||||
---|---|---|---|---|---|---|---|
Cases | Events | Median survival (months) | P value | HR | 95%CI | P value | |
Gender, male/ female | 70/ 34 | 48/ 24 | 22.1/ 19 | 0.8936 | |||
Age, < 60/ ≥60 | 33/ 71 | 19/ 53 | 27.4/ 18.5 | 0.0836 | |||
Serum CA199 (U/ml) | |||||||
< 39, ≥39 | 17/ 67 | 10/ 48 | 20.0/ 12.7 | 0.348 | |||
≥ 39, ≥1000 | 67/ 20 | 48/ 14 | 12.7/ 11.0 | 0.543 | |||
< 39, ≥1000 | 17/ 20 | 10/ 14 | 20.0/ 11.0 | 0.078 | |||
Location, head/ body or tail | 70/ 34 | 49/ 23 | 20/ 16.9 | 0.4537 | |||
Diameter, ≤4/ > 4 | 81/ 23 | 51/ 21 | 25.3/ 9.1 | < 0.0001**** | 1.594 | 1.224–2.075 | 0.001** |
Histological grade, I, I-II/ II, II-III, III | 65/ 39 | 44/ 28 | 21.9/ 19.2 | 0.7374 | |||
Microscopic vascular invasion, absent/ present | 33/ 71 | 19/ 53 | 30.3/ 18.2 | 0.0146* | 0.537 | ||
Microscopic nerve invasion, absent/ present | 12/ 92 | 8/ 64 | 22.4/ 19.8 | 0.9094 | |||
T stage, T1, 2/ T3, 4 | 57/ 47 | 34/ 38 | 27.6/ 12.9 | 0.0004*** | 0.204 | ||
N stage, N0/ N1,2 | 47/ 57 | 30/ 42 | 25.3/ 18.2 | 0.07 | |||
M stage, M0/ M1 | 102/ 2 | 70/ 2 | 20/ 13.6 | 0.2423 | |||
Clinical stage, I-IIa/ IIb-IV | 35/ 69 | 19/ 53 | 30.3/ 18.2 | 0.0051** | 2.127 | 1.235–3.665 | 0.007** |
circNEIL3 expression, low/ high | 52/ 52 | 29/ 43 | 28.4/ 15.3 | 0.0002*** | 1.995 | 1.225–3.248 | 0.006** |
miR-432-5p expression, low/ high | 52/ 52 | 40/ 32 | 14.8/ 26.1 | 0.0059** | 0.137 | ||
ADAR1 expression, low/ high | 52/ 52 | 32/ 40 | 25.4/ 13.4 | 0.0023** | 1.765 | 1.079–2.889 | 0.024* |