Publications by authors named "Yelena Karpova"

12 Publications

  • Page 1 of 1

β2-adrenoreceptor Signaling Increases Therapy Resistance in Prostate Cancer by Upregulating MCL1.

Mol Cancer Res 2020 12 14;18(12):1839-1848. Epub 2020 Sep 14.

Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina.

There is accumulating evidence that continuous activation of the sympathetic nervous system due to psychosocial stress increases resistance to therapy and accelerates tumor growth via β2-adrenoreceptor signaling (ADRB2). However, the effector mechanisms appear to be specific to tumor type. Here we show that activation of ADRB2 by epinephrine, increased in response to immobilization stress, delays the loss of MCL1 apoptosis regulator (MCL1) protein expression induced by cytotoxic drugs in prostate cancer cells; and thus, increases resistance of prostate cancer xenografts to cytotoxic therapies. The effect of epinephrine on MCL1 protein depended on protein kinase A (PKA) activity, but was independent from androgen receptor expression. Furthermore, elevated blood epinephrine levels correlated positively with an increased MCL1 protein expression in human prostate biopsies. In summary, we demonstrate that stress triggers an androgen-independent antiapoptotic signaling via the ADRB2/PKA/MCL1 pathway in prostate cancer cells. IMPLICATIONS: Presented results justify clinical studies of ADRB2 blockers as therapeutics and of MCL1 protein expression as potential biomarker predicting efficacy of apoptosis-targeting drugs in prostate cancer.
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http://dx.doi.org/10.1158/1541-7786.MCR-19-1037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8080265PMC
December 2020

Synthesis and PI3 Kinase Inhibition Activity of Some Novel Trisubstituted Morpholinopyrimidines.

Molecules 2018 Jul 10;23(7). Epub 2018 Jul 10.

Department of Chemistry, Wake Forest University, P.O. Box 7486, Winston-Salem, NC 27109, USA.

A number of new substituted morpholinopyrimidines were prepared utilizing sequential nucleophilic aromatic substitution and cross-coupling reactions. One of the disubstituted pyrimidines was converted into two trisubstituted compounds which were screened as PI3K inhibitors relative to the well-characterized PI3K inhibitor ZSTK474, and were found to be 1.5⁻3-times more potent. A leucine linker was attached to the most active inhibitor since it would remain on any peptide-containing prodrug after cleavage by prostate-specific antigen, and it did not prevent inhibition of AKT phosphorylation and hence the inhibition of PI3K by the modified inhibitor.
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http://dx.doi.org/10.3390/molecules23071675DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6100461PMC
July 2018

Surgical stress delays prostate involution in mice.

PLoS One 2013 6;8(11):e78175. Epub 2013 Nov 6.

Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.

Androgens control growth of prostate epithelial cells and androgen deprivation induces apoptosis, leading to prostate involution. We investigated the effects of surgical stress on prostate involution induced by androgen ablation and determined the underlying mechanisms. Androgen ablation in mice was induced by surgical castration and administration of the anti-androgenic drugs bicalutamide and MDV3100. Surgical stress was induced by sham castration under isoflurane anesthesia. Surgical stress delayed apoptosis and prostate involution induced by anti-androgenic drugs. These effects of stress were prevented by administering the selective beta2-adrenoreceptor antagonist ICI118,551 and were also blocked in BAD(3SA/WT) mice expressing phosphorylation-deficient mutant BAD3SA. These results indicate that apoptosis and prostate involution in response to androgen ablation therapy could be delayed by surgical stress via the beta2-adrenoreceptor/BAD signaling pathway. Thus, surgery could interfere with androgen ablation therapy, whereas administration of beta2-adrenoreceptor antagonists may enhance its efficacy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078175PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819334PMC
August 2014

Combination of the PI3K inhibitor ZSTK474 with a PSMA-targeted immunotoxin accelerates apoptosis and regression of prostate cancer.

Neoplasia 2013 Oct;15(10):1172-83

Department of Cancer Biology and Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC.

The phosphoinositide 3-kinase (PI3K) pathway is activated in most advanced prostate cancers, yet so far treatments with PI3K inhibitors have been at best tumorostatic in preclinical cancer models and do not show significant antitumor efficacy in clinical trials. Results from tissue culture experiments in prostate cancer cells suggest that PI3K inhibitors should be combined with other cytotoxic agents; however, the general toxicity of such combinations prevents translating these experimental data into preclinical and clinical models. We investigated the emerging concept of tumor-targeted synthetic lethality in prostate cancer cells by using the pan-PI3K inhibitor ZSTK474 and the immunotoxin J591PE, a protein chimera between the single-chain variable fragment of the monoclonal antibody J591 against the prostate-specific membrane antigen (PSMA) and the truncated form of the Pseudomonas aeruginosa exotoxin A (PE38QQR). The combination of ZSTK474 and J591PE increased apoptosis within 6 hours and cell death (monitored at 24-48 hours) in the PSMA-expressing cells LNCaP, C4-2, and C4-2Luc but not in control cells that do not express PSMA (PC3 and BT549 cells). Mechanistic analysis suggested that induction of apoptosis requires Bcl-2-associated death promoter (BAD) dephosphorylation and decreased expression of myeloid leukemia cell differentiation protein 1 (MCL-1). A single injection of ZSTK474 and J591PE into engrafted prostate cancer C4-2Luc cells led to consistent and stable reduction of luminescence within 6 days. These results suggest that the combination of a PI3K inhibitor and a PSMA-targeted protein synthesis inhibitor toxin represents a promising novel strategy for advanced prostate cancer therapy that should be further investigated.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819633PMC
http://dx.doi.org/10.1593/neo.13986DOI Listing
October 2013

A pilot study of blood epinephrine levels and CREB phosphorylation in men undergoing prostate biopsies.

Int Urol Nephrol 2014 Mar 21;46(3):505-10. Epub 2013 Sep 21.

Department of Cancer Biology, Wake Forest School of Medicine, Medical Center Blvd., Winston-Salem, NC, 27157, USA.

Purpose: In mouse models of prostate cancer, increased epinephrine levels accelerated tumor growth via the beta2-adrenoreceptor/PKA signaling pathway. It is unknown, however, whether men experience increased epinephrine levels sufficient to activate the beta2-adrenoreceptor/PKA pathway in the prostate gland. We measured epinephrine levels in blood samples collected immediately prior to prostate biopsies and measured phosphorylation of S133CREB (PKA site), S112BAD, T202/Y204ERK, and S473 Akt in prostate biopsy tissue samples.

Methods: Tissue samples and 3 ml of blood were obtained from men (n = 20) recruited from the patients scheduled for prostate biopsies. Epinephrine levels were measured by ELISA. Proteins were extracted from biopsied tissue, and protein phosphorylation was measured by Western blotting with phospho-specific antibodies. Pearson and Spearman's rank correlations were analyzed to assess relationships between blood epinephrine levels and phosphorylation of CREB, BAD, AKT, and ERK.

Results: Epinephrine levels above 1 nM were detected in 5 of 20 patients. A strong positive correlation was observed between increased epinephrine levels and CREB phosphorylation. In contrast, no correlation was observed between epinephrine levels and phosphorylation of ERK, BAD, or AKT.

Conclusion: Our results suggest that increased blood epinephrine levels activate the beta2-adrenoreceptor/PKA signaling pathway in human prostate glands. These results will inform future studies to examine whether beta2-selective blockers can inhibit activation of the epinephrine/ADRB2/PKA pathway in prostate tumors of men with increased epinephrine levels and explore the use of beta2-selective blockers as adjuvant therapy for prostate cancer.
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http://dx.doi.org/10.1007/s11255-013-0513-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959255PMC
March 2014

BAD dephosphorylation and decreased expression of MCL-1 induce rapid apoptosis in prostate cancer cells.

PLoS One 2013 5;8(9):e74561. Epub 2013 Sep 5.

Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America.

PTEN loss and constitutive activation of the PI3K signaling pathway have been associated with advanced androgen-independent prostate cancer. PTEN-deficient prostate cancer C42Luc cells survive in serum-free media and show relative resistance to apoptosis even in the presence of the PI3K inhibitor ZSTK474. Yet, when ZSTK474 is combined with the translation inhibitor cycloheximide, C42Luc cells undergo apoptosis within 6 hours. We identified dephosphorylation of BAD (Bcl2-associated death promoter) as a main apoptosis-regulatory molecule downstream from PI3K, and loss of MCL-1 (Myeloid cell leukemia -1) as a major target of cycloheximide. The combination of MCL-1 knockdown and expression of phosphorylation-deficient mutant BAD2SA is sufficient to trigger rapid apoptosis in prostate cancer cells. These results establish the mechanism for the synergistic induction of apoptosis by the combination of a PI3K inhibitor and of a protein synthesis inhibitor in PTEN-deficient prostate cancer cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0074561PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3764099PMC
June 2014

Behavioral stress accelerates prostate cancer development in mice.

J Clin Invest 2013 Feb 25;123(2):874-86. Epub 2013 Jan 25.

Department of Cancer Biology, Wake Forest School of Medicine, Medical Center Blvd., Winston-Salem, North Carolina 27157, USA.

Prostate cancer patients have increased levels of stress and anxiety. Conversely, men who take beta blockers, which interfere with signaling from the stress hormones adrenaline and noradrenaline, have a lower incidence of prostate cancer; however, the mechanisms underlying stress-prostate cancer interactions are unknown. Here, we report that stress promotes prostate carcinogenesis in mice in an adrenaline-dependent manner. Behavioral stress inhibited apoptosis and delayed prostate tumor involution both in phosphatase and tensin homolog-deficient (PTEN-deficient) prostate cancer xenografts treated with PI3K inhibitor and in prostate tumors of mice with prostate-restricted expression of c-MYC (Hi-Myc mice) subjected to androgen ablation therapy with bicalutamide. Additionally, stress accelerated prostate cancer development in Hi-Myc mice. The effects of stress were prevented by treatment with the selective β2-adrenergic receptor (ADRB2) antagonist ICI118,551 or by inducible expression of PKA inhibitor (PKI) or of BCL2-associated death promoter (BAD) with a mutated PKA phosphorylation site (BADS112A) in xenograft tumors. Effects of stress were also blocked in Hi-Myc mice expressing phosphorylation-deficient BAD (BAD3SA). These results demonstrate interactions between prostate tumors and the psychosocial environment mediated by activation of an adrenaline/ADRB2/PKA/BAD antiapoptotic signaling pathway. Our findings could be used to identify prostate cancer patients who could benefit from stress reduction or from pharmacological inhibition of stress-induced signaling.
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http://dx.doi.org/10.1172/JCI63324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3561807PMC
February 2013

Synthesis and characterization of a novel prostate cancer-targeted phosphatidylinositol-3-kinase inhibitor prodrug.

J Med Chem 2012 Sep 10;55(18):8038-46. Epub 2012 Sep 10.

Department of Cancer Biology and Comprehensive Cancer Center, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA.

The phosphatidylinositol-3-kinase/Akt (PI3K/Akt) pathway is constitutively activated in a substantial proportion of prostate tumors and is considered a key mechanism supporting progression toward an androgen-independent status, for which no effective therapy is available. Therefore, PI3K inhibitors, alone or in combination with other cytotoxic drugs, could potentially be used to treat cancer with a constitutive activated PI3K/Akt pathway. To selectively target advanced prostate tumors with a constitutive activated PI3K/Akt pathway, a prostate cancer-specific PI3K inhibitor was generated by coupling the chemically modified form of the quercetin analogue LY294002 (HO-CH(2)-LY294002, compound 8) with the peptide Mu-LEHSSKLQL, in which the internal sequence HSSKLQ is a substrate for the prostate-specific antigen (PSA) protease. The result is a water-soluble and latent PI3K inhibitor prodrug (compound 11), its activation being dependent on PSA cleavage. Once activated, the L-O-CH(2)-LY294002 (compound 10) can specifically inhibit PI3K in PSA-secreting prostate cancer cells and induce apoptosis with a potency comparable to that of the original LY294002 compound.
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http://dx.doi.org/10.1021/jm300881aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738169PMC
September 2012

Expression of the Bcl-2 protein BAD promotes prostate cancer growth.

PLoS One 2009 Jul 13;4(7):e6224. Epub 2009 Jul 13.

Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.

BAD, a pro-apoptotic protein of the Bcl-2 family, has recently been identified as an integrator of several anti-apoptotic signaling pathways in prostate cancer cells. Thus, activation of EGFR, GPCRs or PI3K pathway leads to BAD phosphorylation and inhibition of apoptosis. Increased levels of BAD in prostate carcinomas have also been reported. It appears contradictory that instead of limiting expression of pro-apoptotic protein, prostate cancer cells choose to increase BAD levels while keeping it under tight phosphorylation control. Analysis of the effect of BAD on prostate cancer xenografts has shown that increased BAD expression enhances tumor growth, while knockdown of BAD expression by shRNA inhibits tumor growth. Tissue culture experiments demonstrated that increased BAD expression stimulates proliferation of prostate cancer cells. These results suggest that increased expression of BAD provides a proliferative advantage to prostate tumors, while BAD dephosphorylation increases sensitivity of prostate cancer cells to apoptosis. Combination of proliferative and apoptotic properties prompts prostate cancer cells to be "addicted" to increased levels of phosphorylated BAD. Thus, kinases that phosphorylate BAD are plausible therapeutic targets; while monitoring BAD phosphorylation could be used to predict tumor response to treatments.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0006224PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2704953PMC
July 2009

Epinephrine protects cancer cells from apoptosis via activation of cAMP-dependent protein kinase and BAD phosphorylation.

J Biol Chem 2007 May 12;282(19):14094-100. Epub 2007 Mar 12.

Department of Cancer Biology, Section on Comparative Medicine, and Center for Human Genomics, Wake Forest University School of Medicine, Winston Salem, NC 27157, USA.

The stress hormone epinephrine is known to elicit multiple systemic effects that include changes in cardiovascular parameters and immune responses. However, information about its direct action on cancer cells is limited. Here we provide evidence that epinephrine reduces sensitivity of cancer cells to apoptosis through interaction with beta(2)-adrenergic receptors. The antiapoptotic mechanism of epinephrine primarily involves phosphorylation and inactivation of the proapoptotic protein BAD by cAMP-dependent protein kinase. Moreover, BAD phosphorylation was observed at epinephrine concentrations found after acute and chronic psychosocial stress. Antiapoptotic signaling by epinephrine could be one of the mechanisms by which stress promotes tumorigenesis and decreases the efficacy of anti-cancer therapies.
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http://dx.doi.org/10.1074/jbc.M611370200DOI Listing
May 2007

Epidermal growth factor protects prostate cancer cells from apoptosis by inducing BAD phosphorylation via redundant signaling pathways.

J Biol Chem 2006 Sep 17;281(37):27367-77. Epub 2006 Jul 17.

Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.

Protection from apoptosis by receptor tyrosine kinases, resistant to the inhibition of phosphatidylinositol 3 '-kinase/Akt and Ras/MEK pathways, has been reported in several cell types, including fibroblasts and epithelial prostate cancer cells; however, mechanisms of this effect were not clear. Here we report that in prostate cancer cells, epidermal growth factor activates two antiapoptotic signaling pathways that impinge on the proapoptotic protein BAD. One signaling cascade operates via the Ras/MEK module and induces BAD phosphorylation on Ser112. Another pathway predominantly relies on Rac/PAK1 signaling that leads to BAD phosphorylation on Ser136. Each of these two pathways is sufficient to protect cells from apoptosis, and therefore both have to be inhibited simultaneously to block epidermal growth factor-dependent survival. Redundancy of antiapoptotic signaling pathways should be considered when therapies targeting antiapoptotic mechanisms are designed.
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http://dx.doi.org/10.1074/jbc.M511485200DOI Listing
September 2006

Diverse antiapoptotic signaling pathways activated by vasoactive intestinal polypeptide, epidermal growth factor, and phosphatidylinositol 3-kinase in prostate cancer cells converge on BAD.

J Biol Chem 2006 Jul 25;281(30):20891-20901. Epub 2006 May 25.

Department of Cancer Biology, Wake Forest University School of Medicine, Winston Salem, North Carolina 27157. Electronic address:

It has been demonstrated that vasoactive intestinal polypeptide, epidermal growth factor, and chronic activation of phosphatidylinositol 3-kinase can protect prostate cancer cells from apoptosis; however, the signaling pathways that they use and molecules that they target are unknown. We report that vasoactive intestinal polypeptide, epidermal growth factor, and phosphatidylinositol 3-kinase activate independent signaling pathways that phosphorylate the proapoptotic protein BAD. Vasoactive intestinal polypeptide operated via protein kinase A, epidermal growth factor required Ras activity, and effects of phosphatidylinositol 3-kinase were predominantly mediated by Akt. BAD phosphorylation was critical for the antiapoptotic effects of each signaling pathway. None of these survival signals was able to rescue cells that express BAD with mutations in phosphorylation sites, whereas knockdown of BAD expression with small hairpin RNA rendered cells insensitive to apoptosis. Taken together, these results identify BAD as a convergence point of several antiapoptotic signaling pathways in prostate cells.
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http://dx.doi.org/10.1074/jbc.M602928200DOI Listing
July 2006