Table 4 Roles of the SCUBE family in cancer biology

SCUBE1

BC

–

Upregulation

–

Clinical: D-dimer level, serum ELISA (normal; BC = 33; 50)

1. SCUBE1 level was higher in BC patients, especially the HER2⁺ group

2. SCUBE1 might be a biomarker of hypercoagulability in BC

[198]

GC

–

Upregulation

–

Clinical: ELISA (normal: GC = 31; 52)

1. Plasma SCUBE1 was significantly increased in GC patients

2. SCUBE1 level did not differ whether metastasis occurred or not

[199]

PC

Suppressor

–

NOTCH2

˙In vitro: proliferation

˙In vivo: xenograft mouse model, IHC

SCUBE1 OE in CAFs resulted in smaller tumor size and less invasion

[200]

–

–

Hedgehog

In vitro: microarray, ELISA, qRT-PCR

SCUBE1 was upregulated after treatment with Smoothened agonist in primary prostate stromal cells

[201]

SCLC

–

–

miR‐22‐3p/WRNIP1

In vitro: colony formation, apoptosis, proliferation, reporter assay

SCUBE1 was upregulated in miR-22-3p OE SCLC cells

[202]

RCC

–

Upregulation

–

Clinical: plasma analysis (normal: RCC = 25; 23)

SCUBE1 level was significantly upregulated in RCC patients

[203]

SCUBE2

BC

Suppressor

Downregulation

BMP2

˙Clinical: IHC (n = 156), survival rate

˙In vitro: proliferation, IP, reporter assay

˙In vivo: xenograft mice model

1. Survival rate was reduced in SCUBE2-negative BC patients

2. SCUBE2 OE suppressed cancer cell proliferation and tumor growth

3. Although the C-terminal region of SCUBE2 interacted with BMP2 as an antagonist, the N-terminal was critical for extracellular secretion of SCUBE2

[112]

Suppressor

High expression in epithelial breast cancer cells

1. E-cadherin

2. BMP2/Smad1/5/8

˙In vitro: domain analysis, cell growth, cell aggregation, IP, IF

․In vivo: xenograft mice model (n = 10 for SCUBE2-ty97 groups; n = 7 for SCUBE2-D4 groups)

1. SCUBE2 OE repressed cell growth or tumor proliferation

2. SCUBE2-D4, which includes Cys-rich domain, CUB domain and C-terminus, was responsible for antagonizing BMP signaling

3. EGF repeats of SCUBE2 were involved in calcium-dependent homophilic interaction and heterophilic interaction with E-cadherin

[22]

Suppressor

Low expression in aggressive breast cancer cells

1. EMT

2. FOXA1/E-cadherin- β-catenin

2. DNA methylation

In vitro: migration, cell aggregation, reporter assay, IF, IP, ChIP, DNA methylation

1. SCUBE2 could enhance epithelial phenotypes, including upregulating E-cadherin expression and reducing migration ability

2. During TGF-β1 induced EMT, the CpG island of SCUBE2 promoter was methylated and thus was repressed

[51]

Suppressor

Downregulation

DNA methylation

˙In vitro: viability, migration, DNMT activity

˙Clinical: IHC (tumor; adjacent = 10; 10), SCUBE2 methylation

1. SCUBE2 was epigenetically modified by DNMT in breast cancer, thus downregulated

2. SCUBE2 KD repressed EMT characteristics

3. EGCG could rescue SCUBE2 loss by inhibiting DNMT expression and activity

[161]

Suppressor

Downregulation

circ_SETD2/miR-155-5p

˙Clinical: qRT-PCR (tumor: adjacent = 54: 54)

˙In vitro: cell cycle, proliferation, migration, apoptosis, reporter assay

˙In vivo: xenograft mice model (control; circ_SETD2 OE = 15: 15)

1. SCUBE2 was downregulated in breast cancer cells

2. SCUBE2 OE resulted in cell cycle arrest, slow growth, enhanced apoptosis and impaired migration ability

3. Circ_SETD2 interacted with miR-155-5p, which targeted SCUBE2

[142]

Suppressor

Downregulated in TNBC

C19MC miRNAs

˙Meta-analysis: miRNA-seq, RNA-seq, TCGA methylation array, GEO database, Oncomine database

˙In vitro: ChIP-seq

1. The expression of SCUBE2 was downregulated in TNBC and co-occurrence with NAT1

2. C19MC miRNAs could target SCUBE2 to contribute to triple-negative phenotype

[140, 141]

Suppressor

Associated with ER⁺ or PR⁺ status

ER⁺ and PR⁺

˙Meta-analysis: TCGA, CCLE, and GEO database, CNV analysis

˙Clinical: IHC, qRT-PCR, survival rate

1. SCUBE2 was associated with ER⁺ or PR⁺ status

2. Deletion of SCUBE2 was associated with poor survival

[132,133,134, 138, 139, 204]

Suppressor

Upregulated in non-metastatic groups

–

˙Meta-analysis: TCGA, METABRIC, and GEO database, IPA

˙Clinical: genomic microarray, gene expression microarray, qRT-PCR, FISH, IHC, RNA Chip, survival rate, mortality, recurrence

1. SCUBE2 was one of the overlapping genes among diverse multigene expression profiles for breast cancer

2. SCUBE2 was downregulated in metastasized tumors and significantly associated with poor survival rate

3. High expression of SCUBE2 was associated with reduced time to disease-related mortality

4. SCUBE2 was associated with immune-poor tumors

[131, 135, 205,206,207,208,209,210]

–

–

SNP analysis

Clinical: cognitive performance, SNP analysis (normal; BC = 82; 138)

1. SCUBE2-related SNPs including rs1136966, rs4910440, and rs6486125 were investigated

2. SCUBE2rs6486125 was associated with attention, executive function, and mental flexibility

[211]

–

–

hsa-miR-9-5p

˙Meta-analysis: miRNA-seq, RNA-seq, and clinical data from TCGA (normal adjacent tissue; BC tissue = 104; 1066)

˙In vitro: qRT-PCR

1. Hsa-miR-9-5p was upregulated in BC and could target SCUBE2

2. Patients with low SCUBE2 levels had a longer median survival time but much lower 10-year survival rate than those with higher levels

[137]

Enhancer (in BCSC)

Upregulated in BCSC

NOTCH

˙In vitro: sphere formation assay, side-population, qRT-PCR, migration

˙In vivo: xenograft mice model (n = 6 each)

1. SCUBE2 was enriched in BCSC population and TNBC, and SCUBE2 OE enhanced cancer stemness, EMT and tumorigenesis

2. SCUBE2 could regulate cancer stemness via NOTCH signaling

[212]

CRC

Suppressor

Downregulation

–

˙Clinical: qRT-PCR, WB, IHC, microarray (tumor; adjacent = 120; 120)

˙In vitro: proliferation, migration, apoptosis

1. SCUBE2 expression was reduced in CRC tissue and was associated with poor prognosis and survival rate

2. SCUBE2 OE led to inhibition of proliferation and migration

[146]

EC

–

Downregulation

–

Clinical: qRT-PCR (n = 60)

SCUBE2 was decreased in grade-3 EC and was positively correlated with ERα, PR and PTEN levels

[150]

GC

Suppressor

Downregulation

–

Clinical: qRT-PCR, WB, IHC, survival rate (tumor; adjacent = 124; 124)

1. SCUBE2 was significantly reduced in GC tissue

2. Decreased SCUBE2 was associated with poor prognosis and lower survival rate

[148]

MG

Suppressor

Downregulation

SHH

˙Clinical: qRT-PCR, WB (normal; MG = 20; 20)

˙In vitro: cell viability, colony formation, migration

˙In vivo: xenograft mice model

1. SCUBE2 was downregulated in MG

2. SCUBE2 OE led to decreased cell viability, colony formation, migration and tumorigenesis

3. SCUBE2 OE inhibited SHH transduction

[145]

NPC

–

Downregulation

–

Meta-analysis: EBI ArrayExpress

SCUBE2 was one of the hypermethylated and downregulated genes in NPC

[151]

NSCLC

Suppressor

Downregulation

SHH

˙Clinical: qRT-PCR, WB (tumor; adjacent = 10; 10)

˙In vitro: apoptosis, migration

1. SCUBE2 was downregulated in NSCLC

2. SCUBE2 suppressed proliferation and migration, and enhanced apoptosis in NSCLC

3. SCUBE2 antagonized SHH signaling

[144]

OSCC

Suppressor

Downregulation

–

˙Clinical: IHC, survival rate (n = 43)

˙Meta-analysis: GeneChip (n = 168), RNA-seq (n = 198)

1. Low level of SCUBE2 indicated poor prognosis

2. SCUBE2 tended to express in lymph node-negative tumors

[213]

PTA

-

Downregulation

–

Meta-analysis: GEO (normal; PTA = 7; 34)

SCUBE2 was downregulated in PTA

[147]

UBC

Suppressor

Downregulation

–

Clinical: IHC (n = 26), ISH

SCUBE2 was reduced in invasive regions and associated with lower survival rate

[149]

SCUBE3

BC

Enhancer

Upregulation

TGF-β1

TWIST1

˙Clinical: IHC, qRT-PCR, prognosis (tumor; adjacent = 30; 30)

˙In vitro: proliferation, migration

˙In vivo: xenograft mice model (control; KD SCUBE3 = 15; 15)

1. SCUBE3 was upregulated in breast cancer

2. SCUBE3 promoted EMT, migration and proliferation

[214]

Enhancer

Upregulation

–

˙Clinical: IHC, survival rate (tumor; adjacent = 140; 140)

˙Meta-analysis: TCGA database (normal; tumor = 114; 1097)

1. SCUBE3 was expressed more in tumor tissue than adjacent tissue

2. Higher level of SCUBE3 was associated with lower survival rate regardless of BC subtypes

[177]

Enhancer

Upregulation

–

Meta-analysis: TCGA (normal; HER⁺ BC = 20; 161)

SCUBE3 was identified as one of six genes in the risk scoring system for HER2⁺ BC

[215]

ccRCC

–

–

–

˙Clinical: DNA methylation (n = 336), model validation (n = 64)

˙Meta-analysis: TCGA

SCUBE3 methylation was not found to be associated with ccRCC-specific survival

[216]

HCC

Enhancer

Upregulation

TGFβ/PI3K/AKT/GSK3β

˙Meta-analysis: TCGA (normal; HCC = 114; 1097)

˙In vitro: proliferation, apoptosis, cell cycle, microarray, IP

˙In vivo: xenograft mice model (n = 10 each group)

1. SCUBE3 was upregulated in HCC, and SCUBE3 KD led to inhibited proliferation, cell cycle arrest and apoptosis

2. SCUBE3 interacted with TβR-II and activated PI3K/AKT signaling pathway

[217]

LC

Enhancer

Upregulation

MMP-2/MMP-9/TβR-II/Smad2/3

˙Clinical: qRT-PCR (tumor; adjacent = 18; 18), IHC (n = 60)

˙In vitro: IP, protein array, migration

˙In vivo: xenograft mice model (control; shSCUBE3 = 8; 7), tail vein assay of cancer metastasis (control; shSCUBE3 = 6; 6)

1. SCUBE3 was enriched in LC, and SCUBE3 KD led to decreased migration, tumorigenesis and metastasis

2. SCUBE3 bound to TβR-II via the CUB domain and induced downstream signaling

3. SCUBE3 CUB domain was cleaved by MMP-2 and MMP-9

[48]

Enhancer

–

Angiogenesis

In vivo: xenograft mice model, MRI, IHC, RNA chip

1. SCUBE3 KD led to larger tumor size at week 1 and less vascular permeability at week 3

2. SCUBE3 KD caused less angiogenesis, EMT and CTCs

[218]

MEL

Enhancer

Upregulation

SOX10/DEPDC1B

˙Clinical: IHC

˙In vitro: qRT-PCR, tube formation assay, ChIP, MS, microarray

˙In vivo: xenograft mice model (n = 5), lung metastasis assay (n = 7), metrigel plug assay (n = 4)

1. SCUBE3 was upregulated in MEL and acted as a pro-angiogenetic factor

2. DEPDC1B regulated ubiquitin ligase CDC16 to stabilize SCUBE3, thus facilitating SCUBE3 expression and secretion

[175]

MG

Enhancer

Upregulation

AKT

˙Clinical: IHC (normal; MG = 3; 3)

˙In vitro: microarray, proliferation, apoptosis

1. SCUBE3 was downregulated in MG cells after treatment with asterosaponin CN-3

2. SCUBE3 KD led to cell cycle arrest in G0/G1 phase and inhibited proliferation

[179]

NSCLC

Enhancer

Upregulation

–

Clinical: IHC, survival rate (tumor; adjacent = 119; 119)

SCUBE3 was highly expressed in NSCLC and associated with low survival rate

[174]

OS

Promoter

Upregulation

–

˙Clinical: survival rate (n = 60)

˙In vitro: cell cycle, proliferation

1. SCUBE3 was highly expressed in OS cell lines, and SCUBE3 KD led to cell cycle arrest in G0/G1 phase and proliferation inhibition

2. High SCUBE3 expression was associated with lower survival rate in OS

[181, 219]

–

–

miR-590-5p

In vitro: lncRNA-seq, mRNA-seq

SCUBE3 was downregulated in miR-590-5p OE OS cell line

[180]

RCC

Suppressor

Downregulation

DNA methylation

˙Clinical: MeDIP (normal; RCC = 3; 9), CoBRA (normal; RCC = 24; 60), qRT-PCR

˙In vitro: colony formation

1. Promoter of SCUBE3 was highly methylated in RCC and was correlated with lower survival probability

2. SCUBE3 KD led to enhanced anchorage-independent growth potential

[183]

SACC

–

Downregulation

miR-885-5p

˙Clinical: mRNA-seq, miRNA-seq, qRT-PCR (tumor; adjacent = 6; 6), IHC (n = 20)

˙In vitro: reporter assay

1. SCUBE3 was downregulated in SACC

2. The 3’UTR of SCUBE3 contained the miR-885-5p target site, and miR-885-5p was upregulated in SACC

[220]