Bifunctionality and Antitumor Efficacy of ZG-126, a Vitamin D Receptor Agonist/Histone Deacetylase Inhibitor Hybrid Molecule.

Analogues of hormonal vitamin D, 1,25-dihydroxyvitamin D (1,25D), signal through the nuclear vitamin D receptor (VDR). They have potential in combination therapies with other anticancer agents such as histone deacetylase inhibitors (HDACi's). Here, we characterize the ZG series of hybrid compounds that combine HDACi within the backbone of a VDR agonist. All display improved solubility, with ZG-126 being the most robustly bifunctional molecule in multiple cell lines. ZG-126 is well tolerated and strongly induces VDR target gene expression in vivo at therapeutic doses. Its antitumor efficacy is superior to 1,25D and the HDACi SAHA, separately or together, in mouse models of melanoma and triple-negative breast cancer (TNBC). Notably, ZG-126 treatment reduces metastases almost 4-fold in an aggressive TNBC model. ZG-126 also reduces total macrophage infiltration and the proportion of immunosuppressive M2-polarized macrophages in TNBC tumors by 2-fold. ZG-126 thus represents a bifunctional and efficacious anticancer agent with improved physicochemical properties.

NEDD9 links anaplastic thyroid cancer stemness to chromosomal instability through integrated centrosome asymmetry and DNA sensing regulation.

Stemness and chromosomal instability (CIN) are two common contributors to intratumor heterogeneity and therapy relapse in advanced cancer, but their interplays are poorly defined. Here, in anaplastic thyroid cancer (ATC), we show that ALDH+ stem-like cancer cells possess increased CIN-tolerance owing to transcriptional upregulation of the scaffolding protein NEDD9. Thyroid patient tissues and transcriptomic data reveals NEDD9/ALDH1A3 to be co-expressed and co-upregulated in ATC. Compared to bulk ALDH- cells, ALDH+ cells were highly efficient at propagating CIN due to their intrinsic tolerance of both centrosome amplification and micronuclei. ALDH+ cells mitigated the fitness-impairing effects of centrosome amplification by partially inactivating supernumerary centrosomes. Meanwhile, ALDH+ cells also mitigated cell death caused by micronuclei-mediated type 1 interferon secretion by suppressing the expression of the DNA-sensor protein STING. Both mechanisms of CIN-tolerance were lost upon RNAi-mediated NEDD9 silencing. Both in vitro and in vivo, NEDD9-depletion attenuated stemness, CIN, cell/tumor growth, while enhancing paclitaxel effectiveness. Collectively, these findings reveal that ATC progression can involve an ALDH1A3/NEDD9-regulated program linking their stemness to CIN-tolerance that could be leveraged for ATC treatment.

Novel Aurora A and Protein Kinase C (α, ß1, ß2, and θ) Multitarget Inhibitors: Impact of Selenium Atoms on the Potency and Selectivity.

Aurora kinases and protein kinase C (PKC) have been shown to be involved in different aspects of cancer progression. To date, no dual Aurora/PKC inhibitor with clinical efficacy and low toxicity is available. Here, we report the identification of compound 2e as a potent small molecule capable of selectively inhibiting Aurora A kinase and PKC isoforms α, ß1, ß2 and θ. Compound 2e demonstrated significant inhibition of the colony forming ability of metastatic breast cancer cells in vitro and metastasis development in vivo. In vitro kinase screening and molecular modeling studies revealed the critical role of the selenium-containing side chains within 2e, where selenium atoms were shown to significantly improve its selectivity and potency by forming additional interactions and modulating the protein dynamics. In comparison to other H-bonding heteroatoms such as sulfur, our studies suggested that these selenium atoms also confer more favorable PK properties.

Identification of R-Spondin Gene Signature Predictive of Metastatic Progression in BRAFV600E-Positive Papillary Thyroid Cancer.

Papillary thyroid carcinoma (PTC) is the most common malignancy of the thyroid gland and early stages are curable. However, a subset of PTCs shows an unusually aggressive phenotype with extensive lymph node metastasis and higher incidence of locoregional recurrence. In this study, we investigated a large cohort of PTC cases with an unusual aggressive phenotype using a high-throughput RNA sequencing (RNA-Seq) to identify differentially regulated genes associated with metastatic PTC. All metastatic PTC with mutated BRAF (V600E) but not BRAF wild-type expressed an up-regulation of R-Spondin Protein 4 (RSPO4) concomitant with an upregulation of genes involved in focal adhesion and cell-extracellular matrix signaling. Further immunohistochemistry validation confirmed the upregulation of these target genes in metastatic PTC cases. Preclinical studies using established PTC cell lines support that RSPO4 overexpression is associated with BRAF V600E mutation and is a critical upstream event that promote activation of kinases of focal adhesion signaling known to drive cancer cell locomotion and invasion. This finding opens up the potential of co-targeting B-Raf, RSPO and focal adhesion proteins as a pharmacological approach for aggressive BRAF V600E PTC.

Chitosan/PCL nanoparticles can improve anti-neoplastic activity of 5-fluorouracil in head and neck cancer through autophagy activation.

Head and neck squamous cell carcinoma (HNSCC), a prevalent cancer worldwide, has a high incidence of loco-regional dissemination, frequent recurrence, and lower 5-year survival rates. Current gold standard treatments for advanced HNSCC rely primarily on radiotherapy and chemotherapy but with limited efficacy and significant side effects. In this study, we characterized a novel 5-fluorouracil (5-FU) carrier composed of chitosan solution (CS) and polycaprolactone (PCL) microparticles (MPs) in HNSCC preclinical models. The designed MPs were evaluated for their size, morphology, drug entrapment efficiency (EE%) and in vitro drug release profile. The anti-cancer activity of 5-FU-loaded particles was assessed in HNSCC human cell lines (CAL27 and HSC3) and in a preclinical mouse model (AT84) utilizing cell proliferation and survival, cell motility, and autophagy endpoints. The results demonstrated a 38.57 % in 5-FU entrapment efficiency associated with reduced 5-FU in vitro release up to 96 h post-exposure. Furthermore, CS-decorated PCL MPs were able to promote a significant inhibition of cancer cell proliferation based on the metabolic and colony formation assays, in comparison to controls. In contrast, CS-decorated PCL MPs did not influence the pharmacological efficacy of 5-FU to inhibit in vitro cancer cell migration. Last, cell protein analysis revealed a significant increase of autophagy and cell death evaluated by LC3-II expression and PARP1 cleavage, respectively. In summary, these results support the potential utility of CS-decorated PCL MPs as an effective 5-FU-delivery carrier to improve HNSCC therapeutic management.

Co-Overexpression of TWIST1-CSF1 Is a Common Event in Metastatic Oral Cancer and Drives Biologically Aggressive Phenotype.

Invasive oral squamous cell carcinoma (OSCC) is often ulcerated and heavily infiltrated by pro-inflammatory cells. We conducted a genome-wide profiling of tissues from OSCC patients (early versus advanced stages) with 10 years follow-up. Co-amplification and co-overexpression of TWIST1, a transcriptional activator of epithelial-mesenchymal-transition (EMT), and colony-stimulating factor-1 (CSF1), a major chemotactic agent for tumor-associated macrophages (TAMs), were observed in metastatic OSCC cases. The overexpression of these markers strongly predicted poor patient survival (log-rank test, p = 0.0035 and p = 0.0219). Protein analysis confirmed the enhanced expression of TWIST1 and CSF1 in metastatic tissues. In preclinical models using OSCC cell lines, macrophages, and an in vivo matrigel plug assay, we demonstrated that TWIST1 gene overexpression induces the activation of CSF1 while TWIST1 gene silencing down-regulates CSF1 preventing OSCC invasion. Furthermore, excessive macrophage activation and polarization was observed in co-culture system involving OSCC cells overexpressing TWIST1. In summary, this study provides insight into the cooperation between TWIST1 transcription factor and CSF1 to promote OSCC invasiveness and opens up the potential therapeutic utility of currently developed antibodies and small molecules targeting cancer-associated macrophages.

A novel orally available seleno-purine molecule suppresses triple-negative breast cancer cell proliferation and progression to metastasis by inducing cytostatic autophagy.

Patients with triple-negative breast cancer (TNBC) often have a poor prognosis largely due to lack of effective targeted therapy. Using a library of seleno-purines coupled to a high-throughput biochemical enzymatic assays we identified a potent pharmacological enhancer of autophagy (referred herein as SLLN-15) that selectively activated cytostatic macroautophagy/autophagy in TNBC preclinical models. SLLN-15 induced a dose-dependent anti-proliferative activity in the TNBC cell lines MDA-MB-231 and BT-20 via induction of autophagy and autophagic flux. This induction was associated with a selective inhibition of AKT-MTOR signaling. Conversely, rapamycin, a known autophagy inducer and MTOR inhibitor, was unable to duplicate SLLN-15's effect on TNBC cells. Inhibition of autophagy by siRNA-mediated targeting of the autophagy regulators, BECN1, ATG5 and ATG7 or using 3-methyladenine (3-MA), significantly protected against SLLN-15-induced inhibition of cell viability, further supporting that SLLN-15-induced inhibition of cancer cell proliferation was autophagy-dependent. SLLN-15-induced autophagy in TNBC cells was also associated with decreased AURKA expression, decreased AKT phosphorylation and subsequent blockage of the AKT-MTOR pathway. In vivo, oral SLLN-15 revealed a potent anticancer and anti-metastatic activity in mice bearing TNBC. Altogether, this study describes a novel regulator of mammalian autophagy, with potential utility as an experimental therapeutic for TNBCs. Abbreviations: 3-MA: 3-methyladenine; ATG5: autophagy related 5; ATG7: autophagy related 7; AURKA: aurora kinase A; AURKB: aurora kinase B; BECN1: beclin 1; CQ: chloroquine; DMSO: dimethyl sulfoxide; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; ERBB2: erb-b2 receptor tyrosine kinase 2; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; PARP1: poly(ADP-ribose) polymerase 1; PI: propidium iodide; SQSTM1/p62: sequestosome 1; TNBC: triple-negative breast cancer.

MNK1/NODAL Signaling Promotes Invasive Progression of Breast Ductal Carcinoma In Situ.

The mechanisms by which breast cancers progress from relatively indolent ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) are not well understood. However, this process is critical to the acquisition of metastatic potential. MAPK-interacting serine/threonine-protein kinase 1 (MNK1) signaling can promote cell invasion. NODAL, a morphogen essential for embryogenic patterning, is often reexpressed in breast cancer. Here we describe a MNK1/NODAL signaling axis that promotes DCIS progression to IDC. We generated MNK1 knockout (KO) or constitutively active MNK1 (caMNK1)-expressing human MCF-10A-derived DCIS cell lines, which were orthotopically injected into the mammary glands of mice. Loss of MNK1 repressed NODAL expression, inhibited DCIS to IDC conversion, and decreased tumor relapse and metastasis. Conversely, caMNK1 induced NODAL expression and promoted IDC. The MNK1/NODAL axis promoted cancer stem cell properties and invasion in vitro. The MNK1/2 inhibitor SEL201 blocked DCIS progression to invasive disease in vivo. In clinical samples, IDC and DCIS with microinvasion expressed higher levels of phospho-MNK1 and NODAL versus low-grade (invasion-free) DCIS. Cumulatively, our data support further development of MNK1 inhibitors as therapeutics for preventing invasive disease. SIGNIFICANCE: These findings provide new mechanistic insight into progression of ductal carcinoma and support clinical application of MNK1 inhibitors to delay progression of indolent ductal carcinoma in situ to invasive ductal carcinoma.

TRAF2 Cooperates with Focal Adhesion Signaling to Regulate Cancer Cell Susceptibility to Anoikis.

TRAF2, a RING finger adaptor protein, plays an important function in tumor necrosis factor (TNF)- and TNF-like weak inducer of apoptosis (TWEAK)-dependent signaling, in particular during inflammatory and immune responses. We identified a functional interaction of TRAF2 with focal adhesion (FA) signaling involving the focal adhesion kinase (FAK) in the regulation of cell susceptibility to anoikis. Comparison of TRAF2-proficient (TRAF2+/+) versus TRAF2-deficient (TRAF2-/-), and FAK-proficient (FAK+/+) versus FAK-deficient (FAK-/-) mouse embryonic fibroblasts and their matched reconstituted cells demonstrated that TRAF2 interacts physically with the N-terminal portion of FAK and colocalizes to cell membrane protrusions. This interaction was found to be critical for promoting resistance to cell anoikis. Similar results were confirmed in the human breast cancer cell line MDA-MB-231, where TRAF2 and FAK downregulation promoted cell susceptibility to anoikis. In human breast cancer tissues, genomic analysis of The Cancer Genome Atlas database revealed coamplification of TRAF2 and FAK in breast cancer tissues with a predictive value for shorter survival, further supporting a potential role of TRAF2-FAK cooperative signaling in cancer progression.

Efficacy of hybrid vitamin D receptor agonist/histone deacetylase inhibitors in vitamin D-resistant triple-negative 4T1 breast cancer.

Hormonal 1,25-dihydroxyvitamin D (1,25D) and its analogues have shown efficacy in some preclinical models of cancer. However, many models are resistant to the antiproliferative effects of 1,25D or its analogues in vitro or in vivo, and such compounds have failed in the clinic as monotherapies because of tumor resistance. Given the observed synergism between 1,25D analogues and histone deacetylase inhibitors (HDACi) in 1,25D-resistant cells, we previously developed a series of hybrid secosteroidal and easily assembled non-secosteroidal analogues that combined agonism for the vitamin D receptor and HDACi in a single backbone. These compounds displayed enhanced efficacy against 1,25D-resistant malignant cells in vitro. Structure/function studies led to synthesis of several non-secosteroidal variants in which HDACi potency was optimized without substantially sacrificing VDR agonism. Here, we present the first studies of efficacy in vivo of two of these compounds, DK-366 and DK-406, in the aggressive mouse 4T1 model of triple-negative breast cancer, a form of the disease for which treatment options are limited. 4T1 cells are resistant in vitro to the cytostatic and cytotoxic effects of 1,25D and the potent HDACi SAHA individually up to concentrations of 1µM and 50µM, respectively, whereas combinations of the two are efficacious. In vitro, DK-366 or -406 induced dose-dependent arrest of cell proliferation and cytotoxicity at 10-20µM. In vivo, the maximum tolerated dose (MTD) of DK-366 and DK-406 were 2.5 and 5.0mg/kg, respectively. Although the compounds induced hypercalcemia at elevated doses, consistent with VDR agonism in vivo, they both reduced tumor burden at doses below their MTD's. Moreover, in a separate experiment, DK-406 at 5mg/kg reduced 4T1 lung metastases by at least 50%. Under the same conditions, 1,25D (0.25µg/kg) and SAHA (25mg/kg) combined had no effect on tumor burden or on lung metastases. These experiments show that hybrid compounds are bioavailable and efficacious against a particularly aggressive model of metastatic breast cancer, providing strong support for the therapeutic potential of the hybrid concept.

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma.

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase-interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations.

Endosomal sorting and c-Cbl targeting of paxillin to autophagosomes regulate cell-matrix adhesion turnover in human breast cancer cells.

Post-translational mechanisms regulating cell-matrix adhesion turnover during cell locomotion are not fully elucidated. In this study, we uncovered an essential role of Y118 site-specific tyrosine phosphorylation of paxillin, an adapter protein of focal adhesion complexes, in paxillin recruitment to autophagosomes to trigger turnover of peripheral focal adhesions in human breast cancer cells. We demonstrate that the Rab-7 GTPase is a key upstream regulator of late endosomal sorting of tyrosine118-phosphorylated paxillin, which is subsequently recruited to autophagosomes via the cargo receptor c-Cbl. Essentially, this recruitment involves a direct and selective interaction between Y118-phospho-paxillin, c-Cbl, and LC3 and is independent from c-Cbl E3 ubiquitin ligase activity. Interference with the Rab7-paxillin-autophagy regulatory network using genetic and pharmacological approaches greatly impacted focal adhesion stability, cell locomotion and progression to metastasis using a panel of human breast cancer cells. Together, these results provide novel insights into the requirement of phospho-site specific post-translational mechanism of paxillin for autophagy targeting to regulate cell-matrix adhesion turnover and cell locomotion in breast cancer cells.

Insights into a novel nuclear function for Fascin in the regulation of the amino-acid transporter SLC3A2.

Fascin 1 (FSCN1) is a cytoskeleton-associated protein recognized to function primarily in the regulation of cytoskeleton structure and formation of plasma membrane protrusions. Here we report a novel nuclear function for Fascin 1. Biochemical studies and genome wide localization using ChIP-seq identified phosphorylated Fascin 1 (pFascin) in complexes associated with transcription and that it co-localizes with histone H3 Lys4 trimethylation (H3K4me3) on chromatin. Gene expression profiling identified genes affected by Fascin 1 including SLC3A2, a gene encoding for a plasma membrane transporter that regulates intracellular amino acid levels. RbBP5, a subunit of the H3K4 histone methyltransferase (HMT) complex was found to interact with Fascin 1 supporting its role in H3K4me3 establishment at target genes. Moreover, we show that changes to SLC3A2 levels affect amino acid-mediated mTORC1 activation. These results reveal that Fascin 1 has a yet undiscovered nuclear function as an epigenetic modulator of genes essential for amino acid metabolism.

microRNA 338-3p exhibits tumor suppressor role and its down-regulation is associated with adverse clinical outcome in prostate cancer patients.

MicroRNAs (miRNAs) are small non-coding RNAs that function in transcriptional and post-transcriptional regulation of gene expression. Several miRNAs have been implicated in regulating prostate cancer (PCa) progression. Deregulations of miRNA regulatory networks have been reported in ERG positive PCa, which accounts for ~50 % of PCa and have been suggested to affect tumor aggressiveness. The function of miR338-3p, its prognostic significance, and its association with ERG positive PCa has not been fully investigated. Using microarray expression profiling, we identified miRNA338-3p as among the top deregulated miRNAs associated with ERG status in PCa. We investigated miR338-3p function using in vitro and in vivo experimental models and its expression was assessed and validated in clinical samples and a public cohort of localized and metastatic prostate cancer. miR338-3p was significantly down-regulated with disease progression from benign prostate tissue to primary and metastatic lesions. In localized disease, patients with lower miR338-3p expression levels showed increased association to biochemical recurrence and several adverse pathological parameters compared to patients with higher miRNA338-3p tissue expression levels. Using in vitro PCa cell models, overexpression of miR338-3p resulted in a decrease in cell invasion and expression of chemokine signalling genes CXCL12, CXCR4, and CXCR7. In vivo, orthotropic implantation of PC3 cells stably expressing miR338-3p was associated with a significant decrease in tumor weights compared to control cells. miR338-3p has anti-proliferative and anti-invasive properties. It affects CXCR4 axis, and its down-regulation is associated with adverse clinical outcomes in PCa patients.

Predominant Rab-GTPase amplicons contributing to oral squamous cell carcinoma progression to metastasis.

Metastatic oral squamous cell carcinoma (OSCC) is frequently associated with recurrent gene abnormalities at specific chromosomal loci. Here, we utilized array comparative genomic hybridization and genome-wide screening of metastatic and non-metastatic tongue tumors to investigate genes potentially contributing to OSCC progression to metastasis. We identified predominant amplifications of chromosomal regions that encompass the RAB5, RAB7 and RAB11 genes (3p24-p22, 3q21.3 and 8p11-12, respectively) in metastatic OSCC. The expression of these Rab GTPases was confirmed by immunohistochemistry in OSCC tissues from a cohort of patients with a follow-up of 10 years. A significant overexpression of Rab5, Rab7 and Rab11 was observed in advanced OSCC cases and co-overexpression of these Rabs was predictive of poor survival (log-rank test, P = 0.006). We generated a Rab interaction network and identified central Rab interactions of relevance to metastasis signaling, including focal adhesion proteins. In preclinical models, mRNA and protein expression levels of these Rab members were elevated in a panel of invasive OSCC cell lines, and their down-regulation prevented cell invasion at least in part via inhibition of focal adhesion disassembly. In summary, our results provide insights into the cooperative role of Rab gene amplifications in OSCC progression and support their potential utility as prognostic markers and therapeutic approach for advanced OSCC.

Dynamin 2 interacts with connexin 26 to regulate its degradation and function in gap junction formation.

Connexin 26 (Cx26), a protein involved in gap junctional intercellular communication, has an essential function during organ and tissue development. Its deregulation, in part due to inherent mutations, is associated with pathological conditions including congenital deafness. Regulation of Cx26 protein level is critical for its function but the molecular mechanisms involved are partially understood. This study identifies dynamin 2 (Dyn2) as a Cx26 interactor in yeast and mammalian cells. Deletion studies revealed that Cx26-Dyn2 interaction involves the C-terminus of Cx26 and the GTPase effector domain of Dyn2, which is of particular importance for the regulation of the endocytic pathway. Dyn2 inhibition using siRNA or dynasore resulted in reduced Cx26 degradation at the plasma membrane and this was associated with change in gap junctional intercellular communication (GJIC). Furthermore, we demonstrate that Dyn2 regulates Cx26 endocytosis and ubiquitination. These results establish Dyn2 as a Cx26 partner in the regulation of GJIC.

The significance of dynamin 2 expression for prostate cancer progression, prognostication, and therapeutic targeting.

Dynamin 2 (Dyn2) is essential for intracellular vesicle formation and trafficking, cytokinesis, and receptor endocytosis. In this study, we investigated the implication of Dyn2 as a prognostic marker and therapeutic target for progressive prostate cancer (PCA). We evaluated Dyn2 protein expression by immunohistochemistry in two cohorts: men with localized PCA treated by retropubic radical prostatectomy (n = 226), and men with advanced/castrate-resistant PCA (CRPC) treated by transurethral resection of prostate (TURP) (n = 253). The role of Dyn2 in cell invasiveness was assessed by in vitro and in vivo experiments using androgen-responsive and refractory PCA preclinical models. Dyn2 expression was significantly increased across advanced stages of PCA compared to benign prostate tissue (P < 0.0001). In the CRPC cohort, high Dyn2 was associated with higher Gleason score (P = 0.004) and marginally with cancer-specific mortality (P = 0.052). In preclinical models, Dyn2 gene silencing significantly reduced cell migration and invasion in vitro, as well as tumor size and lymph node metastases in vivo. In isolated PCA cells, Dyn2 was found to regulate focal adhesion turnover, which is critical for cell migration; this mechanism requires full Dyn2 compared to mutants deficient in GTPase activity. In conclusion, Dyn2 overexpression is associated with neoplastic prostate epithelium and is associated with poor prognosis. Inhibition of Dyn2 prevents cell invasiveness in androgen-responsive and -refractory PCA models, supporting the potential benefit of Dyn2 to serve as a therapeutic target for advanced PCA.

Total synthesis and biological activity of marine alkaloid Eudistomins Y1-Y7 and their analogues.

Eudistomin Y class compounds are a series of ß-carbolines which was originally isolated from a marine turnicate or ascidian near the South Korea Sea. These compounds contain bromo-substituted groups, which is one of the typical characters of marine natural products. We report herein the chemical synthesis and biological evaluation of seven new ß-carboline-based metabolites, Eudistomins Y1-Y7, and their hydroxyl-methylated phenyl derivatives. Using bromo-substituted tryptamines and bromo-substituted phenylglyoxals as the key intermediates, Eudistomins Y1-Y7 and their derivatives were synthesized via the acid-catalyzed Pictet-Spengler reaction and fully characterized by 1H- and 13C-NMR and mass spectroscopy. Biological studies revealed that all of the compounds showed moderate growth inhibitory activity against breast carcinoma cell line MDA-231 with IC50 of 15-63 µM and the inhibitory activities of hydroxyl-methylated phenyl products were higher than that of the corresponding natural products Eudistomins Y1-Y7.