Table 1 Examples of drugs used in ER-positive breast cancer treatment

Fulvestrant (Faslodex)

Induces ER degradation, nonsteroidal selective estrogen receptor degrader (SERD)

FDA approved

[288,289,290,291,292]

Tamoxifen

Nonsteroidal selective estrogen receptor modulator (SERM)

FDA approved

[6,294,, 288, 293–295]

Raloxifene hydrochloride

Nonsteroidal selective estrogen receptor modulator (SERM)

FDA approved

[296,297,298,299,300,301]

Toremifene (Fareston)

Nonsteroidal selective estrogen receptor modulator (SERM)

FDA approved

[301, 302]

ARN-810

Nonsteroidal selective estrogen receptor degrader (SERD)

Clinical trial

[303, 304]

AZD9496

Nonsteroidal selective estrogen receptor degrader (SERD)

Clinical trial

[305, 306]

RAD1901

Nonsteroidal selective estrogen receptor degrader (SERD)

Clinical trial

[307,308,309]

Letrozole (Femara)

Nonsteroidal inhibitor of estrogen synthesis (aromatase inhibitor)

FDA approved

[310,311,312,313]

Anastrozole (Arimidex)

Nonsteroidal inhibitor of estrogen synthesis (aromatase inhibitor)

FDA approved

[314,315,316,317]

Exemestane (Aromasin)

Nonsteroidal inhibitor of estrogen synthesis (aromatase inhibitor)

FDA approved

[318,319,320,321]

BEZ235

Dual inhibitor of PI3K and mTOR

Clinical trial

[322,323,324,325]

SAR245409

PI3K inhibitor

Clinical trial

[285, 313]

Taselisib

Class I PI3K alpha inhibitor

Clinical trial

[326,327,328]

Buparlisib

PI3K inhibitor, competes for the ATP binding

Clinical trial

[63, 326]

Venetoclax (ABT-199)

Bcl-2 inhibitor

Clinical trial

[329, 330]

Everolimus (Afinitor)

Inhibitor of mTORC1 used both in luminal A and in HER2-positive tumors

FDA approved

[277,278,279, 283]

Temsiroliums

Inhibitors of mTORC1 used in luminal A, TNBC, and HER2-positive tumors

Clinical trial

[331]

Vorinostat (SAHA)

Global inhibitor of HDAC

Clinical trial

[332,333,334]

Entinostat

Inhibitor of HDAC1 and HDAC3

Clinical trial

[335, 336]

Panobinostat

Specific inhibitor of HDAC

Clinical trial

[337,338,339]

Rapamycin

mTOR inhibitor

HER- and ER-positive breast cancer cells

[340,341,342,343,344]

SNIPER(ER)

PROTAC-mediated ER degradation in breast cancer cells

ER-positive breast cancer cells

[98, 345]

BHPI

Modulator of ER-dependent UPR response

ER-positive breast cancer cells

[168, 187, 188, 346]

MAb159

Monoclonal antibody against BiP

ER-positive breast cancer cells

[222]

Plumbagin

BiP downregulator, induces BIK levels

ER-positive breast cancer cells

[220]

Epigallocatechin gallate (EGCG)

Inhibits cellular oxidation and DNA methyltransferase to block EGFR and HER2 activation and can induce UPR response by binding BiP

TNBC, ER- and HER2-positive breast cancer cells

[347,348,349,350,351,352]

Resveratrol

Activates SIRT-1 and inhibits TNF-induced activation of NFkB. Used in combination with bortezomib, reduces cell viability through autophagy inhibition

ER- and HER2-positive breast cancer cells

[353, 354]

Hydroxychloroquine

Autophagy inhibitor, suppresses lysosomal acidification

Clinical trial

[167, 225]