Table 1.

Studies involving the in vivo delivery of CRISPR systems in breast cancer or triple negative breast cancer (TNBC) models.

Delivery Method	Subtype	Material	Applicability/ Delivery of	Target Gene/s	In Vivo Model of Breast Cancer/TNBC	Route and Frequency of Administration	Ref.
Non-viral delivery	Lipid-polymer hybrid nanoparticles	Phenylboronic acid—functionalised low molecular weight polyethyleneimine PEI 1.8k (PEI-PBA)	dCas9-based CRISPR interference system (CRISPRi)	miR-10b	4T1 TNBC allograft	Intravenously Every 5 days for 28 days	[48]
Non-viral delivery	Nanovesicles	Tumour-derived extracellular vesicles—fusogenic anthracycline doxorubicin liposomes (T-DOX)	CRISPR/Cas9	PD-L1	Orthotopic 4T1 TNBC allograft	Subcutaneously 1-day interval	[49]
Non-viral delivery	Nanobubbles	Polyethyleneimine (PEI)	CRISPR/Cas9	Cdh2	Orthotopic 4T1 TNBC allograft	N/A	[50]
Non-viral delivery	Polyethyleneimine–Bovine serum albumin-based nanoparticles	Polyethyleneimine– Bovine serum albumin (PEI-BSA)	CRISPR/Cas9 system in plasmid and ribonucleoprotein format	CD81	BALB/c mice	Intravenously One injection	[51]
Non-viral delivery	DNA-based nanoparticles	Polyglycerol Dimethacrylate	Co-delivery of Cas9/sgRNA ribonucleoprotein and DNAzyme	PLK1 EGR-1	Breast cancer MCF7 xenografts	Intravenously Days 0 and 6	[52]
Non-viral delivery	Targeted core-shell nanoparticles	Polyacrylaminoester (PAA)	Dual plasmids pHR-pCas9	CTCF	Female BALB/c nude mice	Intravenously	[53]
Non-viral delivery	Nanoparticles	Polylysine functionalised black phosphorus (PLL-PBP)	PBP/Cas13a/ crMcl-1 complex	Mcl-1	TNBC MDA-MB-231 xenograft	Intratumourally Every two days for a total of 10 injections	[54]
Non-viral delivery	Autocatalytic brain tumour-targeted nanoparticles	HDL-DES-MDEA polymer	LRRC31 cDNA loaded NPs	LRRC31	Female BALB/c nude mice	Intravenously Days 6 and 11	[30]
Non-viral delivery	Polymeric nanoparticles	Poly-β-amino ester (PBAE)	aPBAE/cas9-Cdk5 complex	Cdk5	TNBC orthotopic 4T1 allograft	Intratumourally Days 7, 10, 13, and 16 post-inoculation of 4T1 cells	[55]
Non-viral delivery	Organic polymer	Poly-glycidyl methacrylate (PGMA)	CRISPR/dCas9 conjugated to the effector domains VPR or SAM	MASPIN CCN6	Breast cancer MCF7 xenograft	Intravenously Every 5 days	[56]
Non-viral delivery	Targeted nanolipogel (tNLGs)	Noncationic lipid bilayer and a biodegradable hydrogel core	Three CRISPR plasmids targeted to different DNA sequences of Lnc2	Lnc2	Orthotopic TNBC MDA-MB-231 xenograft	Intravenously Weekly, administered for 4 weeks	[57]
Viral delivery	Lentiviruses	Lentiviral pSECC vector encoding Cre and CRISPR components	sgRNA encoding vector	PTEN	Cas9-knock-in and mammary tissue-specific Cdh1F/F female mice	Intraductal injection	[19]
Viral delivery	Lentiviruses	Lentiviral	sgRNA encoding vector	PI3KCA Akt1	Mammary tissue specific of the base editor BE3 and Cre, Cas9 knock-in Brca1F/F;Trp53F/F female mice	Intraductal injection	[20]

Abbreviations: CRISPRi, clustered regularly interspaced short palindromic repeats interference; miRNA, microRNA; PD-L1, programmed death-ligand 1; SAM, synergistic activator mediator; sgRNA, single guide RNA; TNBC, triple negative breast cancer; Ref, reference; VPR, VP64-p65-Rta.