Dasatinib inhibits c-src phosphorylation and prevents the proliferation of Triple-Negative Breast Cancer (TNBC) cells which overexpress Syndecan-Binding Protein (SDCBP)

Small Molecule Therapeutics in the Pipeline Targeting for Triple-Negative Breast Cancer: Origin, Challenges, Opportunities, and Mechanisms of Action

Triple-negative breast cancer (TNBC) cells are devoid of estrogen receptors (ERs), progesterone receptor (PRs), and human epidermal growth factor receptor 2 (HER2), and it (TNBC) counts for about 10-15% of all breast cancers. TNBC is highly invasive, having a faster growth rate and a higher risk of metastasis and recurrence. Still, chemotherapy is one of the widely used options for treating TNBC. This study reviewed the histological and molecular characterization of TNBC subtypes, signaling pathways that are aberrantly expressed, and small molecules targeting these pathways, as either single agents or in combination with other therapeutic agents like chemotherapeutics, immunotherapeutics, and antibody-drug conjugates; their mechanisms of action, challenges, and future perspectives were also reviewed. A detailed analytical review was carried out using the literature collected from the SciFinder, PubMed, ScienceDirect, Google Scholar, ACS, Springer, and Wiley databases. Several small molecule inhibitors were found to be therapeutics for treating TNBC. The mechanism of action and the different signaling pathways through which the small molecules exert their effects were studied, including clinical trials, if reported. These small molecule inhibitors include buparlisib, everolimus, vandetanib, apatinib, olaparib, salidroside, etc. Some of the signaling pathways involved in TNBC, including the VEGF, PARP, STAT3, MAPK, EGFR, P13K, and SRC pathways, were discussed. Due to the absence of these biomarkers, drug development for treating TNBC is challenging, with chemotherapy being the main therapeutic agent. However, chemotherapy is associated with chemoresistance and a high toxicity to healthy cells as side effects. Hence, there is a continuous demand for small-molecule inhibitors that specifically target several signaling pathways that are abnormally expressed in TNBC. We attempted to include all the recent developments in this field. Any omission is truly unintentional.

In Vitro and In Vivo Effects of Docetaxel and Dasatinib in Triple-Negative Breast Cancer: A Research Study

Introduction Triple-negative breast cancer (TNBC) comprises a heterogeneous group of tumors with a single trait in common: an evident aggressive nature with higher rates of relapse and lower overall survival in the metastatic context when compared to other subtypes of breast cancer. To date, not a single targeted therapy has been approved for the treatment of TNBC, and cytotoxic chemotherapy remains the standard treatment. In the present experimental study, we examine the effects of the chemotherapeutic docetaxel and the bcr/abl kinase inhibitor dasatinib on TNBC cell lines (in vitro) and on TNBC tumor xenograft mouse models (in vivo). Materials and methods TNBC cell lines were cultivated and treated with various concentrations of docetaxel and dasatinib (5 nM to 100 nM). Cell death and apoptosis were studied by flow cytometry. TNBC cell lines were then injected in BALB/c athymic nude mice to express the tumor in vivo. Four groups of mice were created (group A: control; group B: DOC; group C: DAS; group D: DOC + DAS) and treated, respectively, with the drugs and their combination. Tumors were obtained, maintained in a 10% formaldehyde solution, embedded in paraffin, and sent for further histological evaluation (hematoxylin-eosin staining and immune-histochemical analysis) to assess the tumor growth inhibition. Results The cytotoxic effects of docetaxel seem statistically important, with little effect on apoptosis. The effect of dasatinib in vitro and vivo is statistically important, in terms of apoptosis and tumor reduction, with little adverse effects. Conclusions TNBC is a difficult-to-treat oncologic condition, even in an experimental setting. Promising results concerning the addition of targeted therapies (dasatinib) to the conventional cytotoxic ones (docetaxel) have been shown, awaiting further evaluation.

Mechanosensing via a GpIIb/Src/14-3-3ζ axis critically regulates platelet migration in vascular inflammation

Platelets are not only the first responders in thrombosis and hemostasis but also central players in inflammation. Compared with platelets recruited to thrombi, immune-responsive platelets use distinct effector functions including actin-related protein complex 2/3-dependent migration along adhesive substrate gradients (haptotaxis), which prevents inflammatory bleeding and contributes to host defense. How platelet migration in this context is regulated on a cellular level is incompletely understood. Here, we use time-resolved morphodynamic profiling of individual platelets to show that migration, in contrast to clot retraction, requires anisotropic myosin IIa-activity at the platelet rear which is preceded by polarized actin polymerization at the front to initiate and maintain migration. Integrin GPIIb-dependent outside-in signaling via Gα13 coordinates polarization of migrating platelets to trigger tyrosine kinase c-Src/14-3-3ζ-dependent lamellipodium formation and functions independent of soluble agonists or chemotactic signals. Inhibitors of this signaling cascade, including the clinically used ABL/c-Src inhibitor dasatinib, interfere predominantly with the migratory capacity of platelets, without major impairment of classical platelet functions. In murine inflammation models, this translates to reduced migration of platelets visualized by 4D intravital microscopy, resulting in increased inflammation-associated hemorrhage in acute lung injury. Finally, platelets isolated from patients with leukemia treated with dasatinib who are prone to clinically relevant hemorrhage exhibit prominent migration defects, whereas other platelet functions are only partially affected. In summary, we define a distinct signaling pathway essential for migration and provide novel mechanistic insights explaining dasatinib-related platelet dysfunction and bleeding.

ImmunoPET Imaging Identifies the Optimal Timepoint for Combination Therapy in Xenograft Models of Triple-Negative Breast Cancer

(1) Purpose: The glycoprotein non-metastatic melanoma B (gpNMB) is a type 1 transmembrane protein that is overexpressed in numerous cancers, including triple-negative breast cancer (TNBC). Its overexpression is associated with lower overall survival of patients with TNBC. Tyrosine kinase inhibitors such as dasatinib can upregulate gpNMB expression, which has the potential to enhance therapeutic targeting with anti-gpNMB antibody drug conjugates such as glembatumumab vedotin (CDX-011). Our primary aim is to quantify the degree and identify the timeframe of gpNMB upregulation in xenograft models of TNBC after treatment with the Src tyrosine kinase inhibitor, dasatinib, by longitudinal positron emission tomography (PET) imaging with the 89Zr-labeled anti-gpNMB antibody ([89Zr]Zr-DFO-CR011). The goal is to identify the timepoint at which to administer CDX-011 after treatment with dasatinib to enhance therapeutic efficacy using noninvasive imaging. (2) Methods: First, TNBC cell lines that either express gpNMB (MDA-MB-468) or do not express gpNMB (MDA-MB-231) were treated with 2 μM of dasatinib in vitro for 48 h, followed by Western blot analysis of cell lysates to determine differences in gpNMB expression. MDA-MB-468 xenografted mice were also treated with 10 mg/kg of dasatinib every other day for 21 days. Subgroups of mice were euthanized at 0-, 7-, 14-, and 21-days post treatment, and tumors were harvested for Western blot analysis of tumor cell lysates for gpNMB expression. In a different cohort of MDA-MB-468 xenograft models, longitudinal PET imaging with [89Zr]Zr-DFO-CR011 was performed before treatment at 0 (baseline) and at 14 and 28 days after treatment with (1) dasatinib alone (2) CDX-011 (10 mg/kg) alone, or (3) sequential treatment of dasatinib for 14 days then CDX-011 to determine changes in gpNMB expression in vivo relative to baseline. As a gpNMB-negative control, MDA-MB-231 xenograft models were imaged 21 days after treatment with dasatinib, combination of CDX-011 and dasatinib, and vehicle control. (3) Results: Western blot analysis of MDA-MB-468 cell and tumor lysates showed that dasatinib increased expression of gpNMB in vitro and in vivo at 14 days post treatment initiation. In PET imaging studies of different cohorts of MDA-MB-468 xenografted mice, [89Zr]Zr-DFO-CR011 uptake in tumors (SUVmean = 3.2 ± 0.3) was greatest at 14 days after treatment initiation with dasatinib (SUVmean = 4.9 ± 0.6) or combination of dasatinib and CDX-011 (SUVmean= 4.6 ± 0.2) compared with that at baseline (SUVmean = 3.2 ± 0.3). The highest tumor regression after treatment was observed in the combination-treated group with a percent change in tumor volume relative to baseline (%CTV) of -54 ± 13 compared with the vehicle control-treated group (%CTV = +102 ± 27), CDX-011 group (%CTV = -25 ± 9.8), and dasatinib group (%CTV = -23 ± 11). In contrast, the PET imaging of MDA-MB-231 xenografted mice indicated no significant difference in the tumor uptake of [89Zr]Zr-DFO-CR011 between treated (dasatinib alone or in combination with CDX-011) and vehicle-control groups. (4) Conclusions: Dasatinib upregulated gpNMB expression in gpNMB-positive MDA-MB-468 xenografted tumors at 14 days post treatment initiation, which can be quantified by PET imaging with [89Zr]Zr-DFO-CR011. Furthermore, combination therapy with dasatinib and CDX-011 appears to be a promising therapeutic strategy for TNBC and warrants further investigation.

Does Molecular Profiling of KRAS-Mutant Non-Squamous Non-Small Cell Lung Cancer (NSCLC) Help in Treatment Strategy Planning?

Background: Several studies suggest that patients with KRAS-mutant NSCLC fail to benefit from standard systemic therapies and do not respond to EGFR inhibitors. Most recently, KRAS 12c data suggest specific treatment for improving ORR and OS. There is a clear need for therapies specifically developed for these patients. Moreover, data that might be suggestive of a response to specific therapies, such as BRCA1, are needed, and two mutations that were studied in other malignancies show more response to PARP inhibitors. Molecular profiling has the potential to identify other potential targets that may provide better treatment and novel targeted therapy for KRAS-mutated NSCLC. Methods: We purified RNA from archived tissues of patients with stage I and II NSCLC with wild-type (wt) and mutant (mt) KRAS tumors; paired normal tissue adjacent to the tumor from 20 and 17 patients, respectively, and assessed, using real-time reverse transcriptase−polymerase chain reaction (RT-PCR), the expression of four genes involved in DNA synthesis and repair, including thymidylate synthase (TS), BRCA1, ECCR1, RAP80, and the proto-oncogene SRC. Additionally, we assessed the expression of PD-L1 in mt KRAS tumors with immunohistochemistry using an antibody against PD-L1. Results: Our results show that in mtKRAS tumors, the level of expression of ERCC1, TS, and SRC was significantly increased in comparison to paired normal lung tissue (p ≤ 0.04). The expression of BRCA1 and RAP80 was similar in both mt KRAS tumors and paired normal tissue. Furthermore, the expression of BRCA1, TS, and SRC was significantly increased in wt KRAS tumors relative to their expression in the normal lung tissue (p < 0.044). The expression of ERCC1 and RAP80 was similar in wt KRAS tumors and paired normal tissue. Interestingly, SRC expression in mtKRAS tumors was decreased in comparison to wt KRAS tumors. Notably, there was an expression of PD-L1 in the tumor and stromal cells in a few (5 out of 20) mtKRAS tumors. Our results suggest that a greater ERCC1 expression in mt KRAS tumors might increase platinum resistance in this group of patients, whereas the greater expression of BRCA1 in wt KRAS tumor might be suggestive of the sensitivity of taxanes. Our data also suggest that the combination of an SRC inhibitor with a TS inhibitor, such as pemetrexed, might improve the outcome of patients with NSCLC and in particular, patients with wt KRAS tumors. PD-L1 expression in tumors, and especially stromal cells, suggests a better outcome. Conclusion: mt KRAS NSCLC patients might benefit from a treatment strategy that targets KRAS in combination with therapeutic agents based on pharmacogenomic markers, such as SRC and BRCA1. mtKRAS tumors are likely to be platinum-, taxane-, and pemetrexed-resistant, as well as having a low level of PD-L1 expression; thus, they are less likely to receive single-agent immunotherapy, such as pembrolizumab, as the first-line therapy. wt KRAS tumors with BRCA1 positivity tend to be sensitive to taxane therapy and, potentially, platinum. Our results suggest the need to develop targeted therapies for KRAS-mutant NSCLC or combine the targeting of oncogenic KRAS in addition to other therapeutic agents specific to the molecular profile of the tumor.

Targeting the FAK-Src Complex in Desmoplastic Small Round Cell Tumors, Ewing Sarcoma, and Rhabdomyosarcoma

Desmoplastic small round cell tumors (DSRCTs), Ewing sarcoma (ES), and alveolar and embryonal rhabdomyosarcoma (ARMS and ERMS) are malignant sarcomas typically occurring at young age, with a poor prognosis in the metastatic setting. New treatment options are necessary. Src family kinase inhibitor dasatinib single-agent treatment has been investigated in a phase 2 study in patients with advanced sarcomas including ES and RMS but failed as a single agent in these subtypes. Since previous studies demonstrated high FAK and Src activities in RMS and ES tissue and cell lines, and dasatinib treatment was shown to upregulate activated FAK, we hypothesized that FAK-Src combination treatment could potentially be an interesting treatment option for these tumor types. We examined the effects of targeting the FAK-Src complex by addressing (p)FAK and (p)Src expressions in tumor sections of DSRCT (n = 13), ES (n = 68), ARMS (n = 21), and ERMS (n = 39) and by determining the antitumor effects of single and combined treatment with FAK inhibitor defactinib and multikinase (Abl/SFK) inhibitor dasatinib in vitro on cell lines of each subtype. In vivo effects were assessed in DSRCT and ERMS models. Concurrent pFAK and pSrc expressions (H-score >50) were observed in DSRCT (67%), ES (6%), ARMS (35%), and ERMS (19%) samples. Defactinib treatment decreased pFAK expression and reduced cell viability in all subtypes. Dasatinib treatment decreased pSrc expression and cell viability in each subtype. Combination treatment led to a complete reduction in pFAK and pSrc in each cell line and showed enhanced cell viability reduction, drug synergy, DNA damage induction, and a trend toward higher apoptosis induction in DSRCT, ERMS, and ARMS but not in ES cells. These promising in vitro results unfortunately do not translate into promising in vivo results as we did not observe a significant effect on tumor volume in vivo, and the combination did not show superior effects compared to dasatinib single-agent treatment.

Nanotechnology in the development of small and large molecule tyrosine kinase inhibitors and immunotherapy for the treatment of HER2-positive breast cancer

The HER2 receptor tyrosine kinase is a member of the epidermal growth factor receptor family which includes EGFR, HER3 and HER4. They are known to play critical roles in both normal development and cancer. A subset of breast cancers is associated with the HER2 gene, which is amplified and/or overexpressed in 20-25% of invasive breast cancers and is correlated with tumor resistance to chemotherapy, Metastatic Breast Cancer (MBC) and poor patient survival. The advent of receptor tyrosine kinase inhibitors has improved the prognosis of HER2-postive breast cancers; however, HER2+MBC invariably progresses (acquired resistance or de novo resistance). The monoclonal antibody-based drugs (large molecule TKIs) target the extracellular binding domain of HER2; while the small molecule TKIs act intracellularly to inhibit proliferation and survival signals. We reviewed the modes of action of the TKIs with a view to showing which of the TKIs could be combined in nanoparticles to benefit from the power of nanotechnology (reduced toxicity, improved solubility of hydrophobic drugs, long circulation half-lives, circumventing efflux pumps and preventing capture by the reticuloendothelial system (mononuclear phagocyte system). Nanotherapeutics also mediate the synchronization of the pharmacokinetics and biodistribution of multiple drugs incorporated in the nanoparticles. Novel TKIs that are currently under investigation with or without nanoparticle delivery are mentioned, and nano-based strategies to improve their delivery are suggested. Immunotherapies currently in clinical practice, clinical trials or at the preclinical stage are discussed. However, immunotherapy only works well in relatively small subsets of patients. Combining nanomedicine with immunotherapy can boost therapeutic outcomes, by turning "cold" non-immunoresponsive tumors and metastases into "hot" immunoresponsive lesions.

Repurposing drugs as novel triple negative breast cancer therapeutics

BACKGROUND

Among all the types of breast cancer (BC), triple negative breast cancer (TNBC) is the most aggressive form having high metastasis and recurrence rate with limited treatment options. Conventional treatments such as chemotherapy and radiotherapy have lots of toxic side effects and also no FDA approved therapies are available till now. Repurposing of old clinically approved drugs towards various targets of TNBC is the new approach with lesser side effects and also leads to successful inexpensive drug development with less time consuming. Medicinal plants containg various phytoconstituents (flavonoids, alkaloids, phenols, essential oils, tanins, glycosides, lactones) plays very crucial role in combating various types of diseases and used in drug development process because of having lesser side effects.

OBJECTIVE

The present review focuses in summarization of various categories of repurposed drugs against multitarget of TNBC and also summarizes the phytochemical categories that targets TNBC singly or in combination with synthetic old drugs.

METHODS

Literature information was collected from various databases such as Pubmed, Web of Science, Scopus and Medline to understand and clarify the role and mechanism of repurposed synthetic drugs and phytoconstituents aginst TNBC by using keywords like "breast cancer", "repurposed drugs", "TNBC" and "phytoconstituents".

RESULTS

Various repurposed drugs and phytochemicals targeting different signaling pathways that exerts their cytotoxic activities on TNBC cells ultimately leads to apoptosis of cells and also lowers the recurrence rate and stops the metastasis process.

CONCLUSION

Inhibitory effects seen in different levels, which provides information and evidences to researchers towards drug developments process and thus further more investigations and researches need to be taken to get the better therapeutic treatment options against TNBC.

Anti-growth and pro-apoptotic effects of dasatinib on human oral cancer cells through multi-targeted mechanisms

Dasatinib is an inhibitor of Src that has anti-tumour effects on many haematological and solid cancers. However, the anti-tumour effects of dasatinib on human oral cancers remain unclear. In this study, we investigated the effects of dasatinib on different types of human oral cancer cells: the non-tumorigenic YD-8 and YD-38 and the tumorigenic YD-10B and HSC-3 cells. Strikingly, dasatinib at 10 µM strongly suppressed the growth and induced apoptosis of YD-38 cells and inhibited the phosphorylation of Src, EGFR, STAT-3, STAT-5, PKB and ERK-1/2. In contrast, knockdown of Src blocked the phosphorylation of EGFR, STAT-5, PKB and ERK-1/2, but not STAT-3, in YD-38 cells. Dasatinib induced activation of the intrinsic caspase pathway, which was inhibited by z-VAD-fmk, a pan-caspase inhibitor. Dasatinib also decreased Mcl-1 expression and S6 phosphorylation while increased GRP78 expression and eIF-2α phosphorylation in YD-38 cells. In addition, to its direct effects on YD-38 cells, dasatinib also exhibited anti-angiogenic properties. Dasatinib-treated YD-38 or HUVEC showed reduced HIF-1α expression and stability. Dasatinib alone or conditioned media from dasatinib-treated YD-38 cells inhibited HUVEC tube formation on Matrigel without affecting HUVEC viability. Importantly, dasatinib's anti-growth, anti-angiogenic and pro-apoptotic effects were additionally seen in tumorigenic HSC-3 cells. Together, these results demonstrate that dasatinib has strong anti-growth, anti-angiogenic and pro-apoptotic effects on human oral cancer cells, which are mediated through the regulation of multiple targets, including Src, EGFR, STAT-3, STAT-5, PKB, ERK-1/2, S6, eIF-2α, GRP78, caspase-9/3, Mcl-1 and HIF-1α.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Enhanced Anticancer Activity of Nanoformulation of Dasatinib against Triple-Negative Breast Cancer

Triple negative breast cancer (TNBC) is the most aggressive breast cancer accounting for around 15% of identified breast cancer cases. TNBC lacks human epidermal growth factor receptor 2 (HER2) amplification, is hormone independent estrogen (ER) and progesterone receptors (PR) negative, and is not reactive to current targeted therapies. Existing treatment relies on chemotherapeutic treatment, but in spite of an initial response to chemotherapy, the inception of resistance and relapse is unfortunately common. Dasatinib is an approved second-generation inhibitor of multiple tyrosine kinases, and literature data strongly support its use in the management of TNBC. However, dasatinib binds to plasma proteins and undergoes extensive metabolism through oxidation and conjugation. To protect dasatinib from fast pharmacokinetic degradation and to prolong its activity, it was encapsulated on poly(styrene-co-maleic acid) (SMA) micelles. The obtained SMA-dasatinib nanoparticles (NPs) were evaluated for their physicochemical properties, in vitro antiproliferative activity in different TNBC cell lines, and in vivo anticancer activity in a syngeneic model of breast cancer. Obtained results showed that SMA-dasatinib is more potent against 4T1 TNBC tumor growth in vivo compared to free drug. This enhanced effect was ascribed to the encapsulation of the drug protecting it from a rapid metabolism. Our finding highlights the often-overlooked value of nanoformulations in protecting its cargo from degradation. Overall, results may provide an alternative therapeutic strategy for TNBC management.

Small-Molecule Drug Discovery in Triple Negative Breast Cancer: Current Situation and Future Directions

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, but an effective targeted therapy has not been well-established so far. Considering the lack of effective targets, where do we go next in the current TNBC drug development? A promising intervention for TNBC might lie in de novo small-molecule drugs that precisely target different molecular characteristics of TNBC. However, an ideal single-target drug discovery still faces a huge challenge. Alternatively, other new emerging strategies, such as dual-target drug, drug repurposing, and combination strategies, may provide new insight into the improvement of TNBC therapeutics. In this review, we focus on summarizing the current situation of a series of candidate small-molecule drugs in TNBC therapy, including single-target drugs, dual-target drugs, as well as drug repurposing and combination strategies that will together shed new light on the future directions targeting TNBC vulnerabilities with small-molecule drugs for future therapeutic purposes.

Epigenetic silencing of the ubiquitin ligase subunit FBXL7 impairs c-SRC degradation and promotes epithelial-to-mesenchymal transition and metastasis

Epigenetic plasticity is a pivotal factor that drives metastasis. Here, we show that the promoter of the gene that encodes the ubiquitin ligase subunit FBXL7 is hypermethylated in advanced prostate and pancreatic cancers, correlating with decreased FBXL7 mRNA and protein levels. Low FBXL7 mRNA levels are predictive of poor survival in patients with pancreatic and prostatic cancers. FBXL7 mediates the ubiquitylation and proteasomal degradation of active c-SRC after its phosphorylation at Ser 104. The DNA-demethylating agent decitabine recovers FBXL7 expression and limits epithelial-to-mesenchymal transition and cell invasion in a c-SRC-dependent manner. In vivo, FBXL7-depleted cancer cells form tumours with a high metastatic burden. Silencing of c-SRC or treatment with the c-SRC inhibitor dasatinib together with FBXL7 depletion prevents metastases. Furthermore, decitabine reduces metastases derived from prostate and pancreatic cancer cells in a FBXL7-dependent manner. Collectively, this research implicates FBXL7 as a metastasis-suppressor gene and suggests therapeutic strategies to counteract metastatic dissemination of pancreatic and prostatic cancer cells.

MDA-9/Syntenin (SDCBP): Novel gene and therapeutic target for cancer metastasis

The primary cause of cancer-related death from solid tumors is metastasis. While unraveling the mechanisms of this complicated process continues, our ability to effectively target and treat it to decrease patient morbidity and mortality remains disappointing. Early detection of metastatic lesions and approaches to treat metastases (both pharmacological and genetic) are of prime importance to obstruct this process clinically. Metastasis is complex involving both genetic and epigenetic changes in the constantly evolving tumor cell. Moreover, many discrete steps have been identified in metastatic spread, including invasion, intravasation, angiogenesis, attachment at a distant site (secondary seeding), extravasation and micrometastasis and tumor dormancy development. Here, we provide an overview of the metastatic process and highlight a unique pro-metastatic gene, melanoma differentiation associated gene-9/Syntenin (MDA-9/Syntenin) also called syndecan binding protein (SDCBP), which is a major contributor to the majority of independent metastatic events. MDA-9 expression is elevated in a wide range of carcinomas and other cancers, including melanoma, glioblastoma multiforme and neuroblastoma, suggesting that it may provide an appropriate target to intervene in metastasis. Pre-clinical studies confirm that inhibiting MDA-9 either genetically or pharmacologically profoundly suppresses metastasis. An additional benefit to blocking MDA-9 in metastatic cells is sensitization of these cells to a second therapeutic agent, which converts anti-invasion effects to tumor cytocidal effects. Continued mechanistic and therapeutic insights hold promise to advance development of truly effective therapies for metastasis in the future.

Application of a Biphasic Mathematical Model of Cancer Cell Drug Response for Formulating Potent and Synergistic Targeted Drug Combinations to Triple Negative Breast Cancer Cells

Triple negative breast cancer is a collection of heterogeneous breast cancers that are immunohistochemically negative for estrogen receptor, progesterone receptor, and ErbB2 (due to deletion or lack of amplification). No dominant proliferative driver has been identified for this type of cancer, and effective targeted therapy is lacking. In this study, we hypothesized that triple negative breast cancer cells are multi-driver cancer cells, and evaluated a biphasic mathematical model for identifying potent and synergistic drug combinations for multi-driver cancer cells. The responses of two triple negative breast cancer cell lines, MDA-MB-231 and MDA-MB-468, to a panel of targeted therapy drugs were determined over a broad range of concentrations. The analyses of the drug responses by the biphasic mathematical model revealed that both cell lines were indeed dependent on multiple drivers, and inhibitors of individual drivers caused a biphasic response: a target-specific partial inhibition at low nM concentrations, and an off-target toxicity at μM concentrations. We further demonstrated that combinations of drugs, targeting each driver, cause potent, synergistic, and cell-specific cell killing. Immunoblotting analysis of the effects of the individual drugs and drug combinations on the signaling pathways supports the above conclusion. These results support a multi-driver proliferation hypothesis for these triple negative breast cancer cells, and demonstrate the applicability of the biphasic mathematical model for identifying effective and synergistic targeted drug combinations for triple negative breast cancer cells.

Trastuzumab-Targeted Biodegradable Nanoparticles for Enhanced Delivery of Dasatinib in HER2+ Metastasic Breast Cancer

Dasatinib (DAS) is a multikinase inhibitor that acts on several signaling kinases. DAS is used as a second-line treatment for chronic accelerated myeloid and Philadelphia chromosome-positive acute lymphoblastic leukemia. The therapeutic potential of DAS in other solid tumours is under evaluation. As for many other compounds, an improvement in their pharmacokinetic and delivery properties would potential augment the efficacy. Antibody-targeted biodegradable nanoparticles can be useful in targeted cancer therapy. DAS has shown activity in human epidermal growth factor receptor 2 (HER2) positive tumors, so conjugation of this compound with the anti-HER2 antibody trastuzumab (TAB) with the use of nanocarriers could improve its efficacy. TAB-targeted DAS-loaded nanoparticles were generated by nanotechnology. The guided nanocarriers enhanced in vitro cytotoxicity of DAS against HER2 human breast cancer cell lines. Cellular mechanistic, release studies and nanoparticles stability were undertaken to provide evidences for positioning DAS-loaded TAB-targeted nanoparticles as a potential strategy for further development in HER2-overexpressing breast cancer therapy.

The LQB-223 Compound Modulates Antiapoptotic Proteins and Impairs Breast Cancer Cell Growth and Migration

Drug resistance represents a major issue in treating breast cancer, despite the identification of novel therapeutic strategies, biomarkers, and subgroups. We have previously identified the LQB-223, 11a-N-Tosyl-5-deoxi-pterocarpan, as a promising compound in sensitizing doxorubicin-resistant breast cancer cells, with little toxicity to non-neoplastic cells. Here, we investigated the mechanisms underlying LQB-223 antitumor effects in 2D and 3D models of breast cancer. MCF-7 and MDA-MB-231 cells had migration and motility profile assessed by wound-healing and phagokinetic track motility assays, respectively. Cytotoxicity in 3D conformation was evaluated by measuring spheroid size and performing acid phosphatase and gelatin migration assays. Protein expression was analyzed by immunoblotting. Our results show that LQB-223, but not doxorubicin treatment, suppressed the migratory and motility capacity of breast cancer cells. In 3D conformation, LQB-223 remarkably decreased cell viability, as well as reduced 3D culture size and migration. Mechanistically, LQB-223-mediated anticancer effects involved decreased proteins levels of XIAP, c-IAP1, and Mcl-1 chemoresistance-related proteins, but not survivin. Survivin knockdown partially potentiated LQB-223-induced cytotoxicity. Additionally, cell treatment with LQB-223 resulted in changes in the mRNA levels of epithelial-mesenchymal transition markers, suggesting that it might modulate cell plasticity. Our data demonstrate that LQB-223 impairs 3D culture growth and migration in 2D and 3D models of breast cancer exhibiting different phenotypes.

Poly(Cyclohexene Phthalate) Nanoparticles for Controlled Dasatinib Delivery in Breast Cancer Therapy

The effect on the activity in breast cancer models of the small tyrosine kinase inhibitor dasatinib (DAS), either alone or in combination with other antitumoral agents, has been recently explored. However, DAS is characterized by its low and highly pH-dependent solubility, which could lead to poor uptake of the drug limiting its tumoral efficacy. Thus far, the development of safe and efficient delivery vehicles of DAS to improve the therapeutic efficacy minimizing the toxicity profile is still required. In this work, a biodegradable and biocompatible polyester is assessed, for the first time, as raw material for the generation of polymeric nanoparticles (NPs). NPs of 100 nm with a narrow polydispersity were formulated for the encapsulation of DAS. The enzymatic and cellular degradation of the new drug delivery system has been studied, and the toxicity and blood compatibility evaluated for its potential clinical use. The new material used for the generation of nanoparticles led to encapsulate DAS in an efficient manner with quicker release DAS profile when compared with the FDA-approved biopolymer Polylactide. The new DAS-loaded polymeric nanocarrier gave a superior efficacy when compared to free DAS with no difference in the mechanism of action. The new NPs shown to be a promising DAS delivery system to be further evaluated for breast cancer treatment.

A Tyrosine Kinase Expression Signature Predicts the Post-Operative Clinical Outcome in Triple Negative Breast Cancers

Triple negative breast cancer (TNBC) represent 15% of breast cancers. Histoclinical features and marketed prognostic gene expression signatures (GES) failed to identify good- and poor-prognosis patients. Tyrosine kinases (TK) represent potential prognostic and/or therapeutic targets for TNBC. We sought to define a prognostic TK GES in a large series of TNBC. mRNA expression and histoclinical data of 6379 early BCs were collected from 16 datasets. We searched for a TK-based GES associated with disease-free survival (DFS) and tested its robustness in an independent validation set. A total of 1226 samples were TNBC. In the learning set of samples (N = 825), we identified a 13-TK GES associated with DFS. This GES was associated with cell proliferation and immune response. In multivariate analysis, it outperformed the previously published GESs and classical prognostic factors in the validation set (N = 401), in which the patients classified as "low-risk" had a 73% 5-year DFS versus 53% for "high-risk" patients (p = 1.85 × 10-3). The generation of 100,000 random 13-gene signatures by a resampling scheme showed the non-random nature of our classifier, which was also prognostic for overall survival in multivariate analysis. We identified a robust and non-random 13-TK GES that separated TNBC into subgroups of different prognosis. Clinical and functional validations are warranted.

MDA-9/Syntenin: An emerging global molecular target regulating cancer invasion and metastasis

With few exceptions, metastasis is the terminal stage of cancer with limited therapeutic options. Metastasis consists of numerous phenotypic and genotypic alterations of cells that are directly and indirectly induced by multiple intrinsic (cellular) and extrinsic (micro-environmental) factors. To metastasize, a cancer cell often transitions from an epithelial to mesenchymal morphology (EMT), modifies the extracellular matrix, forms emboli and survives in the circulation, escapes immune surveillance, adheres to sites distant from the initial tumor and finally develops a blood supply (angiogenesis) and colonizes in a secondary niche (a micrometastasis). Scientific advances have greatly enhanced our understanding of the precise molecular and genetic changes, operating independently or collectively, that lead to metastasis. This review focuses on a unique gene, melanoma differentiation associated gene-9 (also known as Syntenin-1; Syndecan Binding Protein (sdcbp); mda-9/syntenin), initially cloned and characterized from metastatic human melanoma and shown to be a pro-metastatic gene. In the last two decades, our comprehension of the diversity of actions of MDA-9/Syntenin on cellular phenotype has emerged. MDA-9/Sytenin plays pivotal regulatory roles in multiple signaling cascades and orchestrates both metastatic and non-metastatic events. Considering the relevance of this gene in controlling cancer invasion and metastasis, approaches have been developed to uniquely and selectively target this gene. We also provide recent updates on strategies that have been successfully employed in targeting MDA-9/Syntenin resulting in profound pre-clinical anti-cancer activity.

Recent therapeutic trends and promising targets in triple negative breast cancer

Breast cancer accounts for 25% of all types of cancer in women, and triple negative breast cancer (TNBC) comprises around 15~20% of breast cancers. Conventional chemotherapy and radiation are the primary systemic therapeutic strategies; no other FDA-approved targeted therapies are yet available as for TNBC. TNBC is generally characterized by a poor prognosis and high rates of proliferation and metastases. Due to these aggressive features and lack of targeted therapies, numerous attempts have been made to discover viable molecular targets for TNBC. Massive cohort studies, clinical trials, and in-depth analyses have revealed diverse molecular alterations in TNBC; however, controversy exists as to whether many of these changes are beneficial or detrimental in caner progression. Here we review the complicated tumorigenic processes and discuss critical findings and therapeutic trends in TNBC with a focus on promising therapeutic approaches, the clinical trials currently underway, and potent experimental compounds under preclinical and evaluation.

Treatment Effects of the Second-Generation Tyrosine Kinase Inhibitor Dasatinib on Autoimmune Arthritis

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease that primarily manifests as persistent synovitis and progressive joint destruction. Imatinib exhibited a therapeutic effect in murine collagen-induced arthritis (CIA) via selective inhibition tyrosine kinases. The second-generation tyrosine kinase inhibitor dasatinib exhibits more durable hematological and cytogenetic effects and more potency compared to imatinib. However, the effect of dasatinib on CIA is poorly understood. The present study investigated the treatment effect of dasatinib on autoimmune arthritis. We demonstrated that dasatinib alleviated arthritis symptoms and histopathological destruction in CIA mice. Dasatinib treatment inhibited the production of proinflammatory cytokines including IL-1β, TNF-α, and IL-6, and promoted the production of the anti-inflammatory cytokine IL-10. Dasatinib treatment also suppressed the expression of anti-mouse CII antibodies including total IgG, IgG1, IgG2, and IgG2b, in CIA mice. We further demonstrated that dasatinib inhibited the migration and proliferation of fibroblast-like synoviocytes (FLS) from RA patients and promoted FLS apoptosis. The mRNA expression of MMP13, VEGF, FGF, and DKK1 was down-regulated in FLS treated with dasatinib. Our findings suggest that dasatinib exhibited treatment effects on CIA mice and that FLS are an important target cell of dasatinib treatment in autoimmune arthritis.

iVS analysis to evaluate the impact of scaffold diversity in the binding to cellular targets relevant in cancer

This study reports the application of inverse virtual screening (iVS) methodologies to identify cellular proteins as suitable targets for a library of heterocyclic small-molecules, with potential pharmacological implications. Standard synthetic procedures allow facile generation of these ligands showing a high degree of core scaffold diversity. Specifically, we have computationally investigated the binding efficacy of the new series for target proteins which are involved in cancer pathogenesis. As a result, nine macromolecules demonstrated efficient binding interactions for the molecular dataset, in comparison to the co-crystallised ligand for each target. Moreover, the iVS analysis led us to confirm that 27 analogues have high affinity for one or more examined cellular proteins. The additional evaluation of ADME and drug score for selected hits also highlights their capability as drug candidates, demonstrating valuable leads for further structure optimisation and biological studies.

Syntenin1/MDA-9 (SDCBP) induces immune evasion in triple-negative breast cancer by upregulating PD-L1

PURPOSE

Syntenin1/SDCBP (syndecan binding protein), also known as melanoma differentiation associated gene-9 (MDA-9), is a PDZ domain-containing molecule, which was initially identified as a key oncogene in melanoma. However, the role of syntenin1 in triple-negative breast cancer (TNBC), especially in suppression of antitumour immune response, remains unknown.

METHODS AND RESULTS

One hundred TNBC tissues were obtained after radical resection and used for analysis. High syntenin1 expression was associated with increased tumour size (r = 0.421, P < 0.001), presence of lymph node metastasis (r = 0.221, P = 0.044) and poor overall survival (P = 0.01) and recurrence-free survival (P = 0.007). Syntenin1 overexpression significantly promoted 4T1 tumour growth and lung metastasis in BALB/c mice by affecting CD8⁺ T cells. Western blot and flow cytometry analyses demonstrated that syntenin1 induced CD8⁺ T cell apoptosis in vitro and in vivo through upregulating PD-L1. Western blot demonstrated that syntenin1 upregulated PD-L1 expression by inducing Tyr705 stat3 phosphorylation, which was further confirmed by stat3 inhibition study. The correlation between syntenin1 and PD-L1 was further confirmed using tumour tissues derived from patients with TNBC (r = 0.509, P < 0.001). Efficacy studies indicated that 4T1-scramble tumour benefitted from anti-PD-L1 therapy (P < 0.001); however, 4T1-syntenin1-KD demonstrated no response to anti-PD-L1 treatment (P = 0.076).

CONCLUSIONS

Syntenin1 exhibits a profound function in mediating T cells apoptosis by upregulating PD-L1 and thus could be used as a prognostic biomarker of TNBC. Tumoural syntenin1 expression corelated with anti-PD-L1 treatment efficacy. Targeting syntenin1-mediated T-cell suppression could be a potential strategy for improving the prognosis of patients with TNBC.

Phase II Study of Paclitaxel and Dasatinib in Metastatic Breast Cancer

BACKGROUND

Overexpression and activation of tyrosine kinase Src has been linked to breast carcinogenesis and bone metastases. We showed the feasibility of combining the SRC inhibitor dasatinib with weekly paclitaxel in patients with metastatic breast cancer (MBC) and herein report the subsequent phase II trial.

PATIENTS AND METHODS

Patients had received ≤ 2 chemotherapy regimens for measurable, HER2-negative MBC. Patients received paclitaxel and dasatinib (120 mg daily) and were assessed according to Response Evaluation Criteria in Solid Tumors for overall response rate (ORR), the primary end point. Secondary end points included progression-free survival (PFS) and overall survival (OS). A 30% ORR (n = 55) was deemed worthy of further investigation. Exploratory biomarkers included N-telopeptide (NTX) and plasma vascular epidermal growth factor (VEGF) receptor 2 as predictors of clinical benefit.

RESULTS

From March 2010 to March 2014, 40 patients, including 2 men enrolled. The study was stopped early because of slow accrual. Overall, 32 patients (80%) had estrogen receptor-positive tumors and 23 (58%) had previously received taxanes. Of the 35 assessable patients, 1 (3%) had complete response and 7 (20%) partial response, resulting in an ORR of 23%. The median PFS and OS was 5.2 (95% confidence interval [CI], 2.9-9.9) and 20.6 (95% CI, 12.9-25.2) months, respectively. As expected, fatigue (75%), neuropathy (65%), and diarrhea (50%) were common side effects, but were generally low-grade. Median baseline NTX was similar in patients who had clinical benefit (8.2 nmol BCE) and no clinical benefit (10.9 nmol BCE). Similarly, median baseline VEGF levels were similar between the 2 groups; 93.0 pg/mL versus 83.0 pg/mL.

CONCLUSION

This phase II study of dasatinib and paclitaxel was stopped early because of slow accrual but showed some clinical activity. Further study is not planned.

Silencing of syndecan-binding protein enhances the inhibitory effect of tamoxifen and increases cellular sensitivity to estrogen

OBJECTIVE

Tamoxifen is used as a complementary treatment for estrogen receptor (ER)-positive breast cancer (BCa), but many patients developed resistance. The aim of this study was to examine the role of syndecan-binding protein (SDCBP) silencing in ER-positive BCa cells.

METHODS

In MCF-7/T47D cells, the effects of SDCBP silence/overexpression on cell proliferation and estrogenic response were examined. Cell proliferation was examined using the MTT assay and cell cycle regulators were examined by Western blot. Estrogen response was examined from a luciferase activity and evaluation of transcript levels of pS2 and progesterone receptor (PR) upon estrogen administration. Samples of ER-positive BCa were stained with ERα, PR, and SDCBP antibodies, and their expression correlations were analyzed.

RESULTS

We found that SDCBP silencing inhibited the proliferation of ER-positive BCa cells and arrested a greater number of cells in the G1 phase of the cell cycle compared to tamoxifen alone, while SDCBP overexpression limited the anti-cancer effects of tamoxifen. SDCBP silencing and overexpression also enhanced and attenuated the estrogenic response, respectively. Expression of SDCBP was negatively correlated with PR, ERα, and the PR/ERα ratio in ER-positive BCa tissue samples.

CONCLUSIONS

SDCBP may be involved in tamoxifen resistance in ER-positive BCa. Tamoxifen treatment combined with SDCBP silencing may provide a novel treatment for endocrine therapy-resistant BCa.

Cytokine Signaling in Tumor Progression

Cytokines are molecules that play critical roles in the regulation of a wide range of normal functions leading to cellular proliferation, differentiation and survival, as well as in specialized cellular functions enabling host resistance to pathogens. Cytokines released in response to infection, inflammation or immunity can also inhibit cancer development and progression. The predominant intracellular signaling pathway triggered by cytokines is the JAK-signal transducer and activator of transcription (STAT) pathway. Knockout mice and clinical human studies have provided evidence that JAK-STAT proteins regulate the immune system, and maintain immune tolerance and tumor surveillance. Moreover, aberrant activation of the JAK-STAT pathways plays an undeniable pathogenic role in several types of human cancers. Thus, in combination, these observations indicate that the JAK-STAT proteins are promising targets for cancer therapy in humans. The data supporting this view are reviewed herein.

Anti-spasmogenic effect of cyproheptadine on guinea-pig ileum

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that lacks targeted therapy options, and patients diagnosed with TNBC have poorer outcomes than patients with other breast cancer subtypes. Emerging evidence suggests that breast cancer stem cells (BCSCs), which have tumor-initiating potential and possess self-renewal capacity, may be responsible for this poor outcome by promoting therapy resistance, metastasis, and recurrence. TNBC cells have been consistently reported to display cancer stem cell (CSC) signatures at functional, molecular, and transcriptional levels. In recent decades, CSC-targeting strategies have shown therapeutic effects on TNBC in multiple preclinical studies, and some of these strategies are currently being evaluated in clinical trials. Therefore, understanding CSC biology in TNBC has the potential to guide the discovery of novel therapeutic agents in the future. In this review, we focus on the self-renewal signaling pathways (SRSPs) that are aberrantly activated in TNBC cells and discuss the specific signaling components that are involved in the tumor-initiating potential of TNBC cells. Additionally, we describe the molecular mechanisms shared by both TNBC cells and CSCs, including metabolic plasticity, which enables TNBC cells to switch between metabolic pathways according to substrate availability to meet the energetic and biosynthetic demands for rapid growth and survival under harsh conditions. We highlight CSCs as potential key regulators driving the aggressiveness of TNBC. Thus, the manipulation of CSCs in TNBC can be a targeted therapeutic strategy for TNBC in the future.