Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off-target effects.

Lysine deacetylases (KDACs or HDACs) are metal-dependent enzymes that regulate lysine acetylation, a post-translational modification that is present on thousands of human proteins, essential for many cellular processes, and often misregulated in diseases. The selective inhibition of KDACs would allow for understanding of the biological roles of individual KDACs and therapeutic targeting of individual enzymes. Recent studies have suggested that purportedly specific KDAC inhibitors have significant off-target binding, but the biological consequences of off-target binding were not evaluated. We compared the effects of treatment with two of the reportedly most KDAC-selective inhibitors, Tubastatin A and PCI-34051, in HT1080 cells in which the endogenous KDAC6 or KDAC8 gene has been mutated to inactivate enzyme catalysis while retaining enzyme expression. Genetic inactivation results in much stronger deacetylation defects on known targets compared to inhibitor treatment. Gene expression analysis revealed that both inhibitors have extensive and extensively overlapping off-target effects in cells, even at low inhibitor doses. Furthermore, Tubastatin A treatment led to increased histone acetylation, while inactivation of KDAC6 or KDAC8 did not. Genetic inactivation of KDAC6, but not KDAC8, impaired tumor formation in a xenograft model system, in contrast to previous reports with KDAC inhibitors suggesting the reverse. We conclude that the majority of observed biological effects of treatment with KDAC inhibitors are due to off-target effects rather than the intended KDAC inhibition. Developing a truly specific KDAC6 inhibitor could be a promising therapeutic avenue, but it is imperative to develop new inhibitors that selectively mimic genetic inactivation of individual KDACs.

Obesity and leptin in breast cancer angiogenesis.

At the time of breast cancer diagnosis, most patients meet the diagnostic criteria to be classified as obese or overweight. This can significantly impact patient outcome: breast cancer patients with obesity (body mass index > 30) have a poorer prognosis compared to patients with a lean BMI. Obesity is associated with hyperleptinemia, and leptin is a well-established driver of metastasis in breast cancer. However, the effect of hyperleptinemia on angiogenesis in breast cancer is less well-known. Angiogenesis is an important process in breast cancer because it is essential for tumor growth beyond 1mm3 in size as well as cancer cell circulation and metastasis. This review investigates the role of leptin in regulating angiogenesis, specifically within the context of breast cancer and the associated tumor microenvironment in obese patients.

Mechanical Disruption by Focused Ultrasound Re-sensitizes ER+ Breast Cancer Cells to Hormone Therapy.

OBJECTIVE: Tamoxifen is the most used agent to treat estrogen receptor-positive (ER+) breast cancer (BC). While it decreases the risk of cancer recurrence by 50%, many patients develop resistance to this treatment, culminating in highly aggressive disease. Tamoxifen resistance comes from the repression of ER transcriptional activity that switches the cancer cells to proliferation via nonhormonal signaling pathways. Here, we evaluate a potential strategy to overcome tamoxifen resistance by focused ultrasound (FUS), a noninvasive approach for the mechanical excitation of cancer cells. METHODS: Resistant and nonresistant ER+ BC cells and xenografts from patients with ER+ BC were treated with tamoxifen, FUS or their combination. The apoptosis, proliferation rate, gene expression and activity of estrogen receptor, and morphological changes were measured in treated cells and tissues. RESULTS: FUS caused the mechanical disruption of tamoxifen-resistant BC cells that in turn led to the upregulation of ERα-encoding gene expression and long-term re-sensitization of the cells to tamoxifen. Patient-derived xenografts treated with Tamoxifen and FUS demonstrated a significant reduction in tumor viability and proliferation and a strong structural damage to tumor cells and extracellular matrix. CONCLUSION: FUS can improve ER+ BC treatment by re-sensitizing the cancer cells to tamoxifen.

Screening of a kinase inhibitor library identified novel targetable kinase pathways in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a highly invasive breast cancer subtype that is challenging to treat due to inherent heterogeneity and absence of estrogen, progesterone, and human epidermal growth factor 2 receptors. Kinase signaling networks drive cancer growth and development, and kinase inhibitors are promising anti-cancer strategies in diverse cancer subtypes. Kinase inhibitor screens are an efficient, valuable means of identifying compounds that suppress cancer cell growth in vitro, facilitating the identification of kinase vulnerabilities to target therapeutically. The Kinase Chemogenomic Set is a well-annotated library of 187 kinase inhibitor compounds that indexes 215 kinases of the 518 in the known human kinome representing various kinase networks and signaling pathways, several of which are understudied. Our screen revealed 14 kinase inhibitor compounds effectively inhibited TNBC cell growth and proliferation. Upon further testing, three compounds, THZ531, THZ1, and PFE-PKIS 29, had the most significant and consistent effects across a range of TNBC cell lines. These cyclin-dependent kinase (CDK)12/CDK13, CDK7, and phosphoinositide 3-kinase inhibitors, respectively, decreased metabolic activity in TNBC cell lines and promote a gene expression profile consistent with the reversal of the epithelial-to-mesenchymal transition, indicating these kinase networks potentially mediate metastatic behavior. These data identified novel kinase targets and kinase signaling pathways that drive metastasis in TNBC.

Loss of Hormone Receptor Expression after Exposure to Fluid Shear Stress in Breast Cancer Cell Lines.

Following metastatic spread, many hormone receptor positive (HR+) patients develop a more aggressive phenotype with an observed loss of the HRs estrogen receptor (ER) and progesterone receptor (PR). During metastasis, breast cancer cells are exposed to high magnitudes of fluid shear stress (FSS). Unfortunately, the role for FSS on the regulation of HR expression and function during metastasis is not fully understood. This study was designed to elucidate the impact of FSS on HR+ breast cancer. Utilizing a microfluidic platform capable of exposing breast cancer cells to FSS that mimics in situ conditions, we demonstrate the impact of FSS exposure on representative HR+ breast cancer cell lines through protein and gene expression analysis. Proteomics results demonstrated that 540 total proteins and 1473 phospho-proteins significantly changed due to FSS exposure and pathways of interest included early and late estrogen response. The impact of FSS on response to 17ß-estradiol (E2) was next evaluated and gene expression analysis revealed repression of ER and E2-mediated genes (PR and SDF1) following exposure to FSS. Western blot demonstrated enhanced phosphorylation of mTOR following exposure to FSS. Taken together, these studies provide initial insight into the effects of FSS on HR signaling in metastatic breast cancer.

Xenohormetic Phytochemicals Inhibit Neovascularization in Microphysiological Models of Vasculogenesis and Tumor Angiogenesis.

Xenohormesis proposes that phytochemicals produced to combat stressors in the host plant exert biochemical effects in animal cells lacking cognate receptors. Xenohormetic phytochemicals such as flavonoids and phytoalexins modulate a range of human cell signaling mechanisms but functional correlations with human pathophysiology are lacking. Here, potent inhibitory effects of grapefruit-derived Naringenin (Nar) and soybean-derived Glyceollins (Gly) in human microphysiological models of bulk tissue vasculogenesis and tumor angiogenesis are reported. Despite this interference of vascular morphogenesis, Nar and Gly are not cytotoxic to endothelial cells and do not prevent cell cycle entry. The anti-vasculogenic effects of Glyceollin are significantly more potent in sex-matched female (XX) models. Nar and Gly do not decrease viability or expression of proangiogenic genes in triple negative breast cancer (TNBC) cell spheroids, suggesting that inhibition of sprouting angiogenesis by Nar and Gly in a MPS model of the (TNBC) microenvironment are mediated via direct effects in endothelial cells. The study supports further research of Naringenin and Glyceollin as health-promoting agents with special attention to mechanisms of action in vascular endothelial cells and the role of biological sex, which can improve the understanding of dietary nutrition and the pharmacology of phytochemical preparations.

Obesity-associated epigenetic alterations and the obesity-breast cancer axis.

Both breast cancer and obesity can regulate epigenetic changes or be regulated by epigenetic changes. Due to the well-established link between obesity and an increased risk of developing breast cancer, understanding how obesity-mediated epigenetic changes affect breast cancer pathogenesis is critical. Researchers have described how obesity and breast cancer modulate the epigenome individually and synergistically. In this review, the epigenetic alterations that occur in obesity, including DNA methylation, histone, and chromatin modification, accelerated epigenetic age, carcinogenesis, metastasis, and tumor microenvironment modulation, are discussed. Delineating the relationship between obesity and epigenetic regulation is vital to furthering our understanding of breast cancer pathogenesis.

Engineering dense tumor constructs via cellular contraction of extracellular matrix hydrogels.

Physical characteristics of solid tumors such as dense internal microarchitectures and pathological stiffness influence cancer progression and treatment. While it is routine to engineer culture substrates and scaffolds with elastic moduli that approximate tumors, these models often fail to capture characteristic internal microarchitectures such as densely compacted concentric ECM fibers at the stromal interface. Contractile mesenchymal cells can solve this engineering challenge by deforming, contracting, and compacting extracellular matrix (ECM) hydrogels to decrease tissue volume and increase tissue density. Here we demonstrate that allowing human fibroblasts of varying origins to freely contract collagen type I-containing hydrogels co-seeded with carcinoma cell spheroids produces a tissue engineered construct with structural features that mimic dense solid tumors in vivo. Morphometry and mechanical testing were conducted in tandem with biochemical analysis of proliferation and viability to confirm that dense carcinoma constructs engineered using this approach capture relevant physical characteristics of solid carcinomas in a tractable format that preserves viability and is amenable to extended culture. The reported method is adaptable to the use of multiple mesenchymal cell types and the inclusion of fibrin in the ECM combined with seeding of endothelial cells to produce prevascularized constructs. The physical dense carcinoma constructs engineered using this approach may provide more clinically relevant venues for studying cancer pathophysiology and the challenges associated with the delivery of macromolecular drugs and cellular immunotherapies to solid tumors.

Sulindac sulfide as a non-immune suppressive γ-secretase modulator to target triple-negative breast cancer.

Introduction: Triple-negative breast cancer (TNBC) comprises a heterogeneous group of clinically aggressive tumors with high risk of recurrence and metastasis. Current pharmacological treatment options remain largely limited to chemotherapy. Despite promising results, the efficacy of immunotherapy and chemo-immunotherapy in TNBC remains limited. There is strong evidence supporting the involvement of Notch signaling in TNBC progression. Expression of Notch1 and its ligand Jagged1 correlate with poor prognosis. Notch inhibitors, including g-secretase inhibitors (GSIs), are quite effective in preclinical models of TNBC. However, the success of GSIs in clinical trials has been limited by their intestinal toxicity and potential for adverse immunological effects, since Notch plays key roles in T-cell activation, including CD8 T-cells in tumors. Our overarching goal is to replace GSIs with agents that lack their systemic toxicity and ideally, do not affect tumor immunity. We identified sulindac sulfide (SS), the active metabolite of FDA-approved NSAID sulindac, as a potential candidate to replace GSIs. Methods: We investigated the pharmacological and immunotherapeutic properties of SS in TNBC models in vitro, ex-vivo and in vivo. Results: We confirmed that SS, a known γ-secretase modulator (GSM), inhibits Notch1 cleavage in TNBC cells. SS significantly inhibited mammosphere growth in all human and murine TNBC models tested. In a transplantable mouse TNBC tumor model (C0321), SS had remarkable single-agent anti-tumor activity and eliminated Notch1 protein expression in tumors. Importantly, SS did not inhibit Notch cleavage in T- cells, and the anti-tumor effects of SS were significantly enhanced when combined with a-PD1 immunotherapy in our TNBC organoids and in vivo. Discussion: Our data support further investigation of SS for the treatment of TNBC, in conjunction with chemo- or -chemo-immunotherapy. Repurposing an FDA-approved, safe agent for the treatment of TNBC may be a cost-effective, rapidly deployable therapeutic option for a patient population in need of more effective therapies.

Nicotinamide N-methyltransferase mediates lipofibroblast-myofibroblast transition and apoptosis resistance.

Metabolism controls cellular phenotype and fate. In this report, we demonstrate that nicotinamide N-methyltransferase (NNMT), a metabolic enzyme that regulates developmental stem cell transitions and tumor progression, is highly expressed in human idiopathic pulmonary fibrosis (IPF) lungs, and is induced by the pro-fibrotic cytokine, transforming growth factor-ß1 (TGF-ß1) in lung fibroblasts. NNMT silencing reduces the expression of extracellular matrix proteins, both constitutively and in response to TGF-ß1. Furthermore, NNMT controls the phenotypic transition from homeostatic, pro-regenerative lipofibroblasts to pro-fibrotic myofibroblasts. This effect of NNMT is mediated, in part, by the downregulation of lipogenic transcription factors, TCF21 and PPARγ, and the induction of a less proliferative but more differentiated myofibroblast phenotype. NNMT confers an apoptosis-resistant phenotype to myofibroblasts that is associated with the downregulation of pro-apoptotic members of the Bcl-2 family, including Bim and PUMA. Together, these studies indicate a critical role for NNMT in the metabolic reprogramming of fibroblasts to a pro-fibrotic and apoptosis-resistant phenotype and support the concept that targeting this enzyme may promote regenerative responses in chronic fibrotic disorders such as IPF.

Targeting Mcl-1 by a small molecule NSC260594 for triple-negative breast cancer therapy.

Triple-negative breast cancers (TNBCs) are aggressive forms of breast cancer and tend to grow and spread more quickly than most other types of breast cancer. TNBCs can neither be targeted by hormonal therapies nor the antibody trastuzumab that targets the HER2 protein. There are urgent unmet medical needs to develop targeted drugs for TNBCs. We identified a small molecule NSC260594 from the NCI diversity set IV compound library. NSC260594 exhibited dramatic cytotoxicity in multiple TNBCs in a dose-and time-dependent manner. NSC260594 inhibited the Myeloid cell leukemia-1 (Mcl-1) expression through downregulation of Wnt signaling proteins. Consistent with this, NSC260594 treatment increased apoptosis, which was confirmed by using an Annexin-V/PI assay. Interestingly, NSC260594 treatment reduced the cancer stem cell (CSC) population in TNBCs. To make NSC260594 more clinically relevant, we treated NSC260594 with TNBC cell derived xenograft (CDX) mouse model, and with patient-derived xenograft (PDX) organoids. NSC260594 significantly suppressed MDA-MB-231 tumor growth in vivo, and furthermore, the combination treatment of NSC260594 and everolimus acted synergistically to decrease growth of TNBC PDX organoids. Together, we found that NSC260594 might serve as a lead compound for triple-negative breast cancer therapy through targeting Mcl-1.

Targeting CaMKK2 Inhibits Actin Cytoskeletal Assembly to Suppress Cancer Metastasis.

Triple-negative breast cancers (TNBC) tend to become invasive and metastatic at early stages in their development. Despite some treatment successes in early-stage localized TNBC, the rate of distant recurrence remains high, and long-term survival outcomes remain poor. In a search for new therapeutic targets for this disease, we observed that elevated expression of the serine/threonine kinase calcium/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) is highly correlated with tumor invasiveness. In validation studies, genetic disruption of CaMKK2 expression or inhibition of its activity with small molecule inhibitors disrupted spontaneous metastatic outgrowth from primary tumors in murine xenograft models of TNBC. High-grade serous ovarian cancer (HGSOC), a high-risk, poor prognosis ovarian cancer subtype, shares many features with TNBC, and CaMKK2 inhibition effectively blocked metastatic progression in a validated xenograft model of this disease. Mechanistically, CaMKK2 increased the expression of the phosphodiesterase PDE1A, which hydrolyzed cyclic guanosine monophosphate (cGMP) to decrease the cGMP-dependent activity of protein kinase G1 (PKG1). Inhibition of PKG1 resulted in decreased phosphorylation of vasodilator-stimulated phosphoprotein (VASP), which in its hypophosphorylated state binds to and regulates F-actin assembly to facilitate cell movement. Together, these findings establish a targetable CaMKK2-PDE1A-PKG1-VASP signaling pathway that controls cancer cell motility and metastasis by impacting the actin cytoskeleton. Furthermore, it identifies CaMKK2 as a potential therapeutic target that can be exploited to restrict tumor invasiveness in patients diagnosed with early-stage TNBC or localized HGSOC. SIGNIFICANCE: CaMKK2 regulates actin cytoskeletal dynamics to promote tumor invasiveness and can be inhibited to suppress metastasis of breast and ovarian cancer, indicating CaMKK2 inhibition as a therapeutic strategy to arrest disease progression.

Ca 2+ /Calmodulin Dependent Protein Kinase Kinase-2 (CaMKK2) promotes Protein Kinase G (PKG)-dependent actin cytoskeletal assembly to increase tumor metastasis.

Triple-negative breast cancers (TNBCs) tend to become highly invasive early during cancer development. Despite some successes in the initial treatment of patients diagnosed with early-stage localized TNBC, the rate of metastatic recurrence remains high with poor long-term survival outcomes. Here we show that elevated expression of the serine/threonine-kinase, Calcium/Calmodulin (CaM)-dependent protein kinase kinase-2 (CaMKK2), is highly correlated with tumor invasiveness. We determined that genetic disruption of CaMKK2 expression, or inhibition of its activity, disrupted spontaneous metastatic outgrowth from primary tumors in murine xenograft models of TNBC. High-grade serous ovarian cancer (HGSOC), a high-risk, poor-prognosis ovarian cancer subtype, shares many genetic features with TNBC, and importantly, CaMKK2 inhibition effectively blocked metastatic progression in a validated xenograft model of this disease. Probing the mechanistic links between CaMKK2 and metastasis we defined the elements of a new signaling pathway that impacts actin cytoskeletal dynamics in a manner which increases cell migration/invasion and metastasis. Notably, CaMKK2 increases the expression of the phosphodiesterase PDE1A which decreases the cGMP-dependent activity of protein kinase G1 (PKG1). This inhibition of PKG1 results in decreased phosphorylation of Vasodilator-Stimulated Phosphoprotein (VASP), which in its hypophosphorylated state binds to and regulates F-actin assembly to facilitate contraction/cell movement. Together, these data establish a targetable CaMKK2-PDE1A-PKG1-VASP signaling pathway that controls cancer cell motility and metastasis. Further, it credentials CaMKK2 as a therapeutic target that can be exploited in the discovery of agents for use in the neoadjuvant/adjuvant setting to restrict tumor invasiveness in patients diagnosed with early-stage TNBC or localized HGSOC.

NEK Family Review and Correlations with Patient Survival Outcomes in Various Cancer Types.

The Never in Mitosis Gene A (NIMA)-related kinases (NEKs) are a group of serine/threonine kinases that are involved in a wide array of cellular processes including cell cycle regulation, DNA damage repair response (DDR), apoptosis, and microtubule organization. Recent studies have identified the involvement of NEK family members in various diseases such as autoimmune disorders, malignancies, and developmental defects. Despite the existing literature exemplifying the importance of the NEK family of kinases, this family of protein kinases remains understudied. This report seeks to provide a foundation for investigating the role of different NEKs in malignancies. We do this by evaluating the 11 NEK family kinase gene expression associations with patients' overall survival (OS) from various cancers using the Kaplan-Meier Online Tool (KMPlotter) to correlate the relationship between mRNA expression of NEK1-11 in various cancers and patient survival. Furthermore, we use the Catalog of Somatic Mutations in Cancer (COSMIC) database to identify NEK family mutations in cancers of different tissues. Overall, the data suggest that the NEK family has varying associations with patient survival in different cancers with tumor-suppressive and tumor-promoting effects being tissue-dependent.

LKB1 signaling and patient survival outcomes in hepatocellular carcinoma.

The liver is a major organ that is involved in essential biological functions such as digestion, nutrient storage, and detoxification. Furthermore, it is one of the most metabolically active organs with active roles in regulating carbohydrate, protein, and lipid metabolism. Hepatocellular carcinoma is a cancer of the liver that is associated in settings of chronic inflammation such as viral hepatitis, repeated toxin exposure, and fatty liver disease. Furthermore, liver cancer is the most common cause of death associated with cirrhosis and is the 3rd leading cause of global cancer deaths. LKB1 signaling has been demonstrated to play a role in regulating cellular metabolism under normal and nutrient deficient conditions. Furthermore, LKB1 signaling has been found to be involved in many cancers with most reports identifying LKB1 to have a tumor suppressive role. In this review, we use the KMPlotter database to correlate RNA levels of LKB1 signaling genes and hepatocellular carcinoma patient survival outcomes with the hopes of identifying potential biomarkers clinical usage. Based on our results STRADß, CAB39L, AMPKα, MARK2, SIK1, SIK2, BRSK1, BRSK2, and SNRK expression has a statistically significant impact on patient survival.

Novel Therapeutic Combination Targets the Growth of Letrozole-Resistant Breast Cancer through Decreased Cyclin B1.

As breast cancer cells transition from letrozole-sensitive to letrozole-resistant, they over-express epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK), and human epidermal growth factor receptor 2 (HER2) while acquiring enhanced motility and epithelial-to-mesenchymal transition (EMT)-like characteristics that are attenuated and reversed by glyceollin treatment, respectively. Interestingly, glyceollin inhibits the proliferation and tumor progression of triple-negative breast cancer (TNBC) and estrogen-independent breast cancer cells; however, it is unlikely that a single phytochemical would effectively target aromatase-inhibitor (AI)-resistant metastatic breast cancer in the clinical setting. Since our previous report indicated that the combination of lapatinib and glyceollin induced apoptosis in hormone-dependent AI-resistant breast cancer cells, we hypothesized that combination therapy would also be beneficial for hormone independent letrozole-resistant breast cancer cells (LTLT-Ca) compared to AI-sensitive breast cancer cells (AC-1) by decreasing the expression of proteins associated with proliferation and cell cycle progression. While glyceollin + lapatinib treatment caused comparable inhibitory effects on the proliferation and migration in both cell lines, combination treatment selectively induced S and G2/M phase cell cycle arrest of the LTLT-Ca cells, which was mediated by decreased cyclin B1. This phenomenon may represent a unique opportunity to design novel combinatorial therapeutic approaches to target hormone-refractory breast tumors.

GD2+ cancer stem cells in triple-negative breast cancer: mechanisms of resistance to breast cancer therapies.

Research has led to the development of tailored treatment options for different cancers in different patients. Despite some treatments being able to provide remarkable responses, nearly all current treatments encounter the same issue: resistance. Here, we discuss our experiences with how breast cancers resist therapies. The focus of our discussion revolves around the cancer stem cell subpopulation and their mechanisms for resistance.

The effect of obesity on adipose-derived stromal cells and adipose tissue and their impact on cancer.

The significant increase in the incidence of obesity represents the next global health crisis. As a result, scientific research has focused on gaining deeper insights into obesity and adipose tissue biology. As a result of the excessive accumulation of adipose tissue, obesity results from hyperplasia and hypertrophy within the adipose tissue. The functional alterations in the adipose tissue are a confounding contributing factor to many diseases, including cancer. The increased incidence and aggressiveness of several cancers, including colorectal, postmenopausal breast, endometrial, prostate, esophageal, hematological, malignant melanoma, and renal carcinomas, result from obesity as a contributing factor. The increased morbidity and mortality of obesity-associated cancers are attributable to increased hormones, adipokines, and cytokines produced by the adipose tissue. The increased adipose tissue levels observed in obese patients result in more adipose stromal/stem cells (ASCs) distributed throughout the body. ASCs have been shown to impact cancer progression in vitro and in preclinical animal models. ASCs influence tumor biology via multiple mechanisms, including the increased recruitment of ASCs to the tumor site and increased production of cytokines and growth factors by ASCs and other cells within the tumor stroma. Emerging evidence indicates that obesity induces alterations in the biological properties of ASCs, subsequently leading to enhanced tumorigenesis and metastasis of cancer cells. As the focus of this review is the interaction and impact of ASCs on cancer, the presentation is limited to preclinical data generated on cancers in which there is a demonstrated role for ASCs, such as postmenopausal breast, colorectal, prostate, ovarian, multiple myeloma, osteosarcoma, cervical, bladder, and gastrointestinal cancers. Our group has investigated the interactions between obesity and breast cancer and the mechanisms that regulate ASCs and adipocytes in these different contexts through interactions between cancer cells, immune cells, and other cell types present in the tumor microenvironment (TME) are discussed. The reciprocal and circular feedback loop between obesity and ASCs and the mechanisms by which ASCs from obese patients alter the biology of cancer cells and enhance tumorigenesis will be discussed. At present, the evidence for ASCs directly influencing human tumor growth is somewhat limited, though recent clinical studies suggest there may be some link.

Expression of Novel Kinase MAP3K19 in Various Cancers and Survival Correlations.

Mitogen Activated Protein (MAP) kinases are a category of serine/threonine kinases that have been demonstrated to regulate intracellular events including stress responses, developmental processes, and cancer progression Although many MAP kinases have been extensively studied in various disease processes, MAP3K19 is an understudied kinase whose activities have been linked to lung disease and fibroblast development. In this manuscript, we use bioinformatics databases starBase, GEPIA, and KMPlotter, to establish baseline expressions of MAP3K19 in different tissue types and its correlation with patient survival in different cancers.

Ceritinib is a novel triple negative breast cancer therapeutic agent.

BACKGROUND: Triple-negative breast cancers (TNBCs) are clinically aggressive subtypes of breast cancer. TNBC is difficult to treat with targeted agents due to the lack of commonly targeted therapies within this subtype. Androgen receptor (AR) has been detected in 12-55% of TNBCs. AR stimulates breast tumor growth in the absence of estrogen receptor (ER), and it has become an emerging molecular target in TNBC treatment. METHODS: Ceritinib is a small molecule inhibitor of tyrosine kinase and it is used in the therapy of non-small lung cancer patients. Enzalutamide is a small molecule compound targeting the androgen receptor and it is used to treat prostate cancer. Combination therapy of these drugs were investigated using AR positive breast cancer mouse xenograft models. Also, combination treatment of ceritinib and paclitaxel investigated using AR- and AR low mouse xenograft and patient derived xenograft models. RESULTS: We screened 133 FDA approved drugs that have a therapeutic effect of AR+ TNBC cells. From the screen, we identified two drugs, ceritinib and crizotinib. Since ceritinib has a well- defined role in androgen independent AR signaling pathways, we further investigated the effect of ceritinib. Ceritinib treatment inhibited RTK/ACK/AR pathway and other downstream pathways in AR+ TNBC cells. The combination of ceritinib and enzalutamide showed a robust inhibitory effect on cell growth of AR+ TNBC cells in vitro and in vivo. Interestingly Ceritinib inhibits FAK-YB-1 signaling pathway that leads to paclitaxel resistance in all types of TNBC cells. The combination of paclitaxel and ceritinib showed drastic inhibition of tumor growth compared to a single drug alone. CONCLUSIONS: To improve the response of AR antagonist in AR positive TNBC, we designed a novel combinational strategy comprised of enzalutamide and ceritinib to treat AR+ TNBC tumors through the dual blockade of androgen-dependent and androgen-independent AR signaling pathways. Furthermore, we introduced a novel therapeutic combination of ceritinib and paclitaxel for AR negative or AR-low TNBCs and this combination inhibited tumor growth to a great extent. All agents used in our study are FDA-approved, and thus the proposed combination therapy will likely be useful in the clinic.