Increasing intratumor C/EBP-β LIP and nitric oxide levels overcome resistance to doxorubicin in triple negative breast cancer

Abstract

BackgroundTriple negative breast cancer (TNBC) easily develops resistance to the first-line drug doxorubicin, because of the high levels of the drug efflux transporter P-glycoprotein (Pgp) and the activation of pro-survival pathways dependent on endoplasmic reticulum (ER). Interfering with these mechanisms may overcome the resistance to doxorubicin, a still unmet need in TNBC.MethodsWe analyzed a panel of human and murine breast cancer cells for their resistance to doxorubicin, Pgp expression, lysosome and proteasome activity, nitrite production, ER-dependent cell death and immunogenic cell death parameters. We evaluated the efficacy of genetic (C/EBP-β LIP induction) and pharmacological strategies (lysosome and proteasome inhibitors), in restoring the ER-dependent and immunogenic-dependent cell death induced by doxorubicin, in vitro and in syngeneic mice bearing chemoresistant TNBC. The results were analyzed by one-way analysis of variance test.ResultsWe found that TNBC cells characterized by high levels of Pgp and resistance to doxorubicin, had low induction of the ER-dependent pro-apoptotic factor C/EBP-β LIP upon doxorubicin treatment and high activities of lysosome and proteasome that constitutively destroyed LIP. The combination of chloroquine and bortezomib restored doxorubicin sensitivity by activating multiple and interconnected mechanisms. First, chloroquine and bortezomib prevented C/EBP-β LIP degradation and activated LIP-dependent CHOP/TRB3/caspase 3 axis in response to doxorubicin. Second, C/EBP-β LIP down-regulated Pgp and up-regulated calreticulin that triggered the dendritic cell (DC)-mediated phagocytosis of tumor cell, followed by the activation of anti-tumor CD8+T-lymphocytes upon doxorubicin treatment. Third, chloroquine and bortezomib increased the endogenous production of nitric oxide that further induced C/EBP-β LIP and inhibited Pgp activity, enhancing doxorubicin’s cytotoxicity. In orthotopic models of resistant TNBC, intratumor C/EBP-β LIP induction - achieved by a specific expression vector or by chloroquine and bortezomib - effectively reduced tumor growth and Pgp expression, increased intra-tumor apoptosis and anti-tumor immune-infiltrate, rescuing the efficacy of doxorubicin.ConclusionsWe suggest that preventing C/EBP-β LIP degradation by lysosome and proteasome inhibitors triggers multiple virtuous circuitries that restore ER-dependent apoptosis, down-regulate Pgp and re-activate the DC/CD8+T-lymphocytes response against TNBC. Lysosome and proteasome inhibitors associated with doxorubicin may overcome the resistance to the drug in TNBC.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0967-0) contains supplementary material, which is available to authorized users.

ABCA1/ABCB1 Ratio Determines Chemo- and Immune-Sensitivity in Human Osteosarcoma

“…Unexpectedly, in osteosarcoma cells with acquired resistance to doxorubicin and high levels of ABCB1, the amount of ABCA1 was reduced. This phenotype was observed also in 3D cultures of osteosarcoma derived from doxorubicin-sensitive cells, which up-regulated ABCB1 and displayed resistance to doxorubicin, as it occurs in colon [25] and breast [38] cancer cells. We cannot exclude that the reduction of ABCA1 plays a role in chemoresistance, together with the increased level of ABCB1.…”

Curcumin-Loaded Solid Lipid Nanoparticles Bypass P-Glycoprotein Mediated Doxorubicin Resistance in Triple Negative Breast Cancer Cells

“…Our results are clinically relevant because chemotherapy based on doxorubicin is one of the first therapeutic options in TNBC. Unluckily, this type of breast cancer results in less responsiveness to doxorubicin than other breast cancer types [61], because of the abundant presence of Pgp [62]. Increasing doxorubicin efficacy in TNBC is still an unmet need, but biocompatible SLNs loaded with CURC may help to achieve this goal.…”

20‐Hydroxyecdysone receptor‐activated Bombyx mori CCAAT/enhancer‐binding protein gamma regulates the expression of BmCBP and subsequent histone H3 lysine 27 acetylation in Bo. mori

“…However, whether homo/heterodimers of BmC/EBPg activate BmCBP expression requires further investigation. C/EBPs are also well-known CCAAT/EBPs and are widely reported to be involved in many cellular processes, such as cell growth and aging (Buck et al, 1999;Schafer et al, 2018), differentiation Radomska et al, 1998;AlSudais et al, 2018;Jeong et al, 2019), injury and inflammation response (Burgess-Beusse and Darlington, 1998;Poli, 1998;Jo et al, 2018), and cellular phenotypes (Lekstrom-Himes and Xanthopoulos, 1998;Salaroglio et al, 2018). In mammals, C/EBPs play pivotal roles in immunoresponse (Dai et al, 2017;Larabee et al, 2018), inflammatory response, liver regeneration, metabolism and numerous diseases (Ramji and Foka, 2002;Pulikkan et al, 2017;Wattanavanitchakorn et al, 2018).…”