Discovery, design, and synthesis of anti-metastatic lead phenylmethylene hydantoins inspired by marine natural products

Maurice M, Donaldson WA. Synthesis and Evaluation of 5-(Heteroarylmethylene)hydantoins as Glycogen Synthase Kinase-3β Inhibitors

Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase which plays a center role in the phosphorylation of a wide variety of proteins, generally leading to their inactivation. As such, GSK-3 is viewed as a therapeutic target. An ever-increasing number of small organic molecule inhibitors of GSK-3 have been reported. Phenylmethylene hydantoins are known to exhibit a wide range of inhibitory activities including for GSK-3β. A family of fourteen 2-heterocycle substituted methylene hydantoins (14, 17-29) were prepared and evaluated for the inhibition of GSK-3β at 25 μM. The IC50 values of five of these compounds was determined; the two best inhibitors are 5-[(4'-chloro-2-pyridinyl)methylene]hydantoin (IC50 = 2.14 ± 0.18 μM) and 5-[(6'-bromo-2-pyridinyl)methylene]hydantoin (IC50 = 3.39 ± 0.16 μM). The computational docking of the compounds with GSK-3β (pdb 1q41) revealed poses with hydrogen bonding to the backbone at Val135. The 5-[(heteroaryl)methylene]hydantoins did not strongly inhibit other metalloenzymes, demonstrating poor inhibitory activity against matrix metalloproteinase-12 at 25 μM and against human carbonic anhydrase at 200 μM, and were not inhibitors for Staphylococcus aureus pyruvate carboxylase at concentrations >1000 μM.

Structure-Activity Relationship Study and Design Strategies of Hydantoin, Thiazolidinedione, and Rhodanine-Based Kinase Inhibitors: A Two-Decade Review

Cancer is one of the most prominent causes of the rapidly growing mortality numbers worldwide. Cancer originates from normal cells that have acquired the capability to alter their molecular, biochemical, and cellular traits. The alteration of cell signaling enzymes, such as kinases, can initiate and amplify cancer progression. As a curative method, the targeted therapy utilized small molecules' capability to inhibit kinase's cellular function. This review provides a brief history (1999-2023) of Small Molecule Kinase Inhibitors (SMKIs) discovery with their molecular perspective. Furthermore, this current review also addresses the application and the development of hydantoin, thiazolidinedione, and rhodanine-based derivatives as kinase inhibitors toward several subclasses (EGFR, PI3K, VEGFR, Pim, c-Met, CDK, IGFR, and ERK) accompanied by their structure-activity relationship study and their molecular interactions. The present work summarizes and compiles all the important structural information essential for developing hydantoin, thiazolidinedione, and rhodanine-based kinase inhibitors to improve their potency in the future.

Spongimides A and B, two new alkaloids from the marine sponge Spongia sp

Two new alkaloids, spongimides A (1) and B (2), along with five known ones (3-7), were isolated from the marine sponge Spongia sp. The structures of 1 and 2 were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compounds 1, 3, and 4 were the first examples of 2,4-imidazolidinediones isolated from this genus. In addition, the cytotoxic and antibacterial activities of compounds 1 and 2 were also evaluated.

Hemimycalins C-E; Cytotoxic and Antimicrobial Alkaloids with Hydantoin and 2-Iminoimidazolidin-4-one Backbones from the Red Sea Marine Sponge Hemimycale sp

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine sponges, we have investigated the sponge Hemimycale sp. The cytotoxic fraction of the organic extract of the sponge afforded three new compounds, hemimycalins C–E (1–3). Their structural assignments were obtained via analyses of their one- and two-dimensional NMR spectra and HRESI mass spectrometry. Hemimycalin C was found to differ from the reported hydantoin compounds in the configuration of the olefinic moiety at C-5–C-6, while hemimycalins D and E were found to contain an 2-iminoimidazolidin-4-one moiety instead of the hydantoin moiety in previously reported compounds from the sponge. Hemimycalins C–E showed significant antimicrobial activity against Escherichia coli and Candida albicans and cytotoxic effects against colorectal carcinoma (HCT 116) and the triple-negative breast cancer (MDA-MB-231) cells.

Discovery of cytotoxic natural products from Red Sea sponges: Structure and synthesis

Marine ecosystem continues to produce a great wealth of molecules endowed with cytotoxic activity towards a large panel of tumor cells. Marine sponges, apparently defenseless organisms are endowed through evolution with a range of cytotoxic metabolites for self protection against predators and space competition. Interestingly, high biodiversity of sponges with Demospongiae and Calcarea species that have yielded numerous bioactive compounds have been accorded in different regions of the Red Sea. This review for the first time provides a comprehensive overview of 123 cytotoxic agents derived from Red Sea sponges with diverse chemical structures covered till mid 2020 showing activities ranging from mildly active to very active against different panels of cancer cell lines. It has been divided according to the different classes of compounds including alkaloids, terpenoids (sesquiterpenes, diterpenes, triterpenes, sesterterpenes, norsesterterpenes), peptides and macrolides, lipids (steroids, fatty acids/amides and glycerides) etc. The enhancement in the cytotoxicity with respect to the molecular structure changes have been described in detail. We have also accounted for the total synthesis of cytotoxic molecules, subereamolline A, aerothionin, asmarine B, norrsolide and latrunculin B showing interesting activity against different cancer cell lines.

Quercetin and Its Nano-Scale Delivery Systems in Prostate Cancer Therapy: Paving the Way for Cancer Elimination and Reversing Chemoresistance

Prostate cancer is the second most leading and prevalent malignancy around the world, following lung cancer. Prostate cancer is characterized by the uncontrolled growth of cells in the prostate gland. Prostate cancer morbidity and mortality have grown drastically, and intensive prostate cancer care is unlikely to produce adequate outcomes. The synthetic drugs for the treatment of prostate cancer in clinical practice face several challenges. Quercetin is a natural flavonoid found in fruits and vegetables. Apart from its beneficial effects, its plays a key role as an anti-cancer agent. Quercetin has shown anticancer potential, both alone and in combination. Therefore, the current study was designed to collect information from the literature regarding its therapeutic significance in the treatment of prostate cancer. Studies performed both in vitro and in vivo have confirmed that quercetin effectively prevents prostate cancer through different underlying mechanisms. Promising findings have also been achieved in clinical trials regarding the pharmacokinetics and human applications of quercetin. In the meantime, epidemiological studies have shown a negative correlation between the consumption of quercetin and the incidence of prostate cancer, and have indicated a chemopreventive effect of quercetin on prostate cancer in animal models. The major issues associated with quercetin are its low bioavailability and rapid metabolism, and these require priority attention. Chemoresistance is another main negative feature concerning prostate cancer treatment. This review highlights the chemotherapeutic effect, chemo preventive effect, and chemoresistance elimination potential of quercetin in prostate cancer. The underlying mechanisms for elimination of prostate cancer and eradication of resistance, either alone or in combination with other agents, are also discussed. In addition, the nanoscale delivery of quercetin is underpinned along with possible directions for future study.

Synthesis and Antiplasmodial Activity of Novel Bioinspired Imidazolidinedione Derivatives

Malaria is an enormous threat to public health, due to the emergence of Plasmodium falciparum resistance to widely-used antimalarials, such as chloroquine (CQ). Current antimalarial drugs are aromatic heterocyclic derivatives, most often containing a basic component with an added alkyl chain in their chemical structure. While these drugs are effective, they have many side effects. This paper presents the synthesis and preliminary physicochemical characterisation of novel bioinspired imidazolidinedione derivatives, where the imidazolidinedione core was linked via the alkylene chain and the basic piperazine component to the bicyclic system. These compounds were tested against the asexual stages of two strains of P. falciparum—the chloroquine-sensitive (D10) and chloroquine-resistant (W2) strains. In parallel, in vitro cytotoxicity was investigated on a human keratinocyte cell line, as well as their hemolytic activity. The results demonstrated that the antiplasmodial effects were stronger against the W2 strain (IC₅₀ between 2424.15–5648.07 ng/mL (4.98–11.95 µM)), compared to the D10 strain (6202.00–9659.70 ng/mL (12.75–19.85 µM)). These molecules were also non-hemolytic to human erythrocytes at a concentration active towards the parasite, but with low toxicity to mammalian cell line. The synthetized derivatives, possessing enhanced antimalarial activity against the CQ-resistant strain of P. falciparum, appear to be interesting antimalarial drug candidates.

Copper-Promoted C-Se Cross-Coupling of 2-Selenohydantoins with Arylboronic Acids in an Open Flask

The modification of Chan-Lam-Evans cross-coupling reaction for the selective Se-arylation of 2-selenohydantoins under base-free mild conditions via aryl boronic acids is described herein. This approach was used to synthesize novel 5-arylidene-3-substituted-2-(arylselanyl)-imidazoline-4-ones with high yields. The anticancer activity of the final compounds was evaluated in vitro against different cancer cells, and thus, the possibility of 5-arylidene-3-substituted-2-(arylselanyl)-imidazoline-4-ones successful application as cytotoxic agents was demonstrated.

Revisiting the Urech Synthesis of Hydantoins: Direct Access to Enantiopure 1,5-Substituted Hydantoins Using Cyanobenziodoxolone

A method for the synthesis of enantiopure 1,5-substituted hydantoins was developed using a hypervalent iodine cyanation reagent (cyanobenziodoxolone, CBX) as a source of electrophilic carbon. Starting from inexpensive commercially available enantiopure protected amino acids, the method allowed the synthesis of various hydantoins without epimerization. Formation of hydantoins from dipeptides was also possible, but partial epimerization was observed in this case. This synthetic strategy is user friendly as CBX is a bench-stable easy-to-handle crystalline reagent and avoids conventional multistep protocols, thus allowing the facile synthesis of a library of chiral hydantoins.

5,5-Diphenyl-2-thioxoimidazolidin-4-one dimethyl sulfoxide monosolvate

In the title solvate, C15H12N2OS·C2H6OS, the thioxoimidazolidin-4-one molecule and solvent molecule are linked by an N—H...O hydrogen bond. The planar imidazolidine ring (r.m.s. deviation = 0.022 Å) is inclined to the phenyl substituents in the 5-position by 69.57 (7) and 72.62 (6)°. In the crystal, N—H...O, C—H...O and C—H...S hydrogen bonds, together with C—H...π interactions, generate [100] chains, which stack along the a-axis direction.

Step economy strategy for the synthesis of amphoteric aminoaldehydes, key intermediates for reduced hydantoins

Despite of the orthogonal reactivity of the N–H aziridines aldehyde, these compounds exist as an equilibrium of three different forms – whereas the dimeric one is mostly observed in a variety of solvents. In this work, we have developed an alternative protocol for the aminoaldehyde dimers synthesis in two steps starting with an organocatalyzed aziridination between α,β-unsaturated aldehydes and a protected amine to afford known isolable and stable N-protected aziridine aldehydes. After Boc-deprotection, dimeric species were immediately formed from monomeric N–H aziridine aldehydes. From this building-block new reduced hydantoins were prepared via [3+2]-annulation with isocyanates.

Marine Invertebrate Metabolites with Anticancer Activities: Solutions to the "Supply Problem"

Marine invertebrates provide a rich source of metabolites with anticancer activities and several marine-derived agents have been approved for the treatment of cancer. However, the limited supply of promising anticancer metabolites from their natural sources is a major hurdle to their preclinical and clinical development. Thus, the lack of a sustainable large-scale supply has been an important challenge facing chemists and biologists involved in marine-based drug discovery. In the current review we describe the main strategies aimed to overcome the supply problem. These include: marine invertebrate aquaculture, invertebrate and symbiont cell culture, culture-independent strategies, total chemical synthesis, semi-synthesis, and a number of hybrid strategies. We provide examples illustrating the application of these strategies for the supply of marine invertebrate-derived anticancer agents. Finally, we encourage the scientific community to develop scalable methods to obtain selected metabolites, which in the authors' opinion should be pursued due to their most promising anticancer activities.

The 5-aromatic hydantoin-3-acetate derivatives as inhibitors of the tumour multidrug resistance efflux pump P-glycoprotein (ABCB1): Synthesis, crystallographic and biological studies

A series of arylpiperazine derivatives of hydantoin-3-acetate, including previously obtained 5,5-diphenylhydantoin (1-7) and new-synthesized spirofluorene-hydantoin derivatives (8-12), were investigated in the search for new inhibitors of the tumour multidrug resistance (MDR) efflux pump P-glycoprotein (P-gp, ABCB1) overexpressed in mouse T-lymphoma cells. Synthesis of new compounds (8-12) was performed. Crystal structures of two compounds (8 and 11) were determined by X-ray diffraction method. The conformations of the investigated molecules (8 and 11) in the crystalline samples are different. The bent conformation seems to be more favourable for biological activity than the extended one. The efflux pump inhibitory properties of the compounds 1-12 were evaluated in the fluorescence uptake assay using rhodamine 123 dye in mouse T-lymphoma model in vitro. Their cytotoxic action was examined, too. All compounds with methyl acetate moiety displayed high potency to inhibit the MDR efflux pump. The most active compound, methyl 2-(1-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-5,5-diphenylhydantoin-3-yl)acetate (5), tested at 1/10 of verapamil concentration displayed the 9-fold higher P-gp inhibitory action.

Bioactive Hydantoin Alkaloids from the Red Sea Marine Sponge Hemimycale arabica

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Hemimycale arabica. The antimicrobial fraction of an organic extract of the sponge afforded two new hydantoin alkaloids, hemimycalins A and B (2 and 3), together with the previously reported compound (Z)-5-(4-hydroxybenzylidene)imidazolidine-2,4-dione (1). The structures of the compounds were determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determinations. Hemimycalins A (2) and B (3) represent the first examples of the natural N-alkylated hydantoins from the sponge Hemimycale arabica. Compounds 1-3 displayed variable antimicrobial activities against E. coli, S. aureus, and C. albicans. In addition, compound 1 displayed moderate antiproliferative activity against the human cervical carcinoma (HeLa) cell line. These findings provide further insight into the chemical diversity as well as the biological activity of this class of compounds.

Natural products from marine organisms with neuroprotective activity in the experimental models of Alzheimer's disease, Parkinson's disease and ischemic brain stroke: their molecular targets and action mechanisms

Continuous increases in the incidence of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and brain stroke demand the urgent development of therapeutics. Marine organisms are well-known producers of natural products with diverse structures and pharmacological activities. Therefore, researchers have endeavored to identify marine natural products with neuroprotective effects. In this regard, this review summarizes therapeutic targets for AD, PD, and ischemic brain stroke and marine natural products with pharmacological activities on the targets according to taxonomies of marine organisms. Furthermore, several marine natural products on the clinical trials for the treatment of neurological disorders are discussed.

Proteasome inhibitor patents (2010 - present)

INTRODUCTION

Over the past 3 years, numerous patents and patent applications have been submitted and published involving compounds designed to inhibit the proteasome. Proteasome inhibition has been of great interest in cancer research since disruption of proteolysis leads to a significant buildup of cytotoxic proteins and activation of apoptotic pathways, particularly in rapidly proliferating cells. The current standards in proteasome inhibition are the only FDA-approved inhibitors, bortezomib and carfilzomib. Although these drugs are quite effective in treating multiple myeloma and other blood tumors, there are shortcomings, including toxicities and resistance. Most of the current patents attempt to improve on existing compounds, by increasing bioavailability and selectivity, while attempting to reduce toxicity. A general categorization of similar compounds was employed to evaluate and compare drug design strategies.

AREAS COVERED

This review focuses on novel compounds and subsequent analogs developed for proteasome inhibition, used in preventing and treating human cancers. A comprehensive description and categorization of patents related to each type of compound and its derivatives, as well as their uses and efficacies as anticancer agents is included. A review of combination therapy patents has also been included.

EXPERT OPINION

Although there are many diverse chemical scaffolds being published, there are few patented proteasome inhibitors whose method of inhibition is genuinely novel. Most patents utilize a destructive chemical warhead to attack the catalytic threonine residue of the proteasome active sites. Few patents try to depart from this, emphasizing the need for developing new mechanisms of action and specific targeting.

Optimization of marine triterpene sipholenols as inhibitors of breast cancer migration and invasion

Sipholenol A, a sipholane triterpene isolated from the Red Sea sponge Callyspongia siphonella, has the ability to reverse multidrug resistance in cancer cells that overexpress P-glycoprotein (P-gp). Here, the antimigratory activity of sipholenol A and analogues are reported against the highly metastatic human breast cancer cell line MDA-MB-231 in a wound-healing assay. Sipholenol A and sipholenone A were semisynthetically optimized using ligand-based strategies to generate structurally diverse analogues in an attempt to maximize their antimigratory activity. A total of 22 semisynthetic ester, ether, oxime, and carbamate analogues were generated and identified by extensive one- and two-dimensional NMR spectroscopy and high-resolution mass spectrometry analyses. Sipholenol A 4β-4-chlorobenzoate and 19,20-anhydrosipholenol A 4β-4-chlorobenzoate esters were the most potent of all tested analogues in the wound-healing assay, with IC(50) values of 5.3 and 5.9 μM, respectively. Generally, ester derivatives showed better antimigratory activities than the carbamate analogues. A KINOMEscan of 19,20-anhydrosipholenol A 4β-benzoate ester against 451 human protein kinases identified protein tyrosine kinase 6 (PTK6) as a potential target. In breast tumor cells, PTK6 promotes growth factor signaling and migration, and as such the semisynthetic sipholanes were evaluated for their ability to inhibit PTK6 phosphorylation in vitro. The two analogues with the highest antimigratory activities, sipholenol A 4β-4-chlorobenzoate and 19,20-anhydrosipholenol A 4β-4-chlorobenzoate esters, also exhibited the most potent inhibition of PTK6 phosphorylation inhibition. None of the compounds exhibited cytotoxicity in a normal epithelial breast cell line. These derivatives were evaluated in an in vitro invasion assay, where sipholenol A succinate potently inhibited MDA-MB-231 cell invasion at 10 μM. These results highlight sipholane triterpenoids as novel antimigratory marine natural products with potential for further development as agents for the control of metastatic breast malignancies.

Olive secoiridoids and semisynthetic bioisostere analogues for the control of metastatic breast cancer

(-)-Oleocanthal (1) and ligstroside aglycone (2) are common bioactive olive oil secoiridoids. Secoiridoid 1 has been previously reported as a c-MET inhibitor. Chemically, (-)-oleocanthal is the elenolic acid ester of the common olive phenolic alcohol tyrosol. Therefore, several analogues (4-13) were synthesized by esterification and carbamoylation of tyrosol using diverse phenolic naturally occurring in olive and heterocyclic acids as elenolic acid bioisosteres to assess the effect of replacing the acid moiety of (-)-oleocanthal. Their c-MET inhibitory activity as well as their antiproliferative, antimigratory, and anti-invasive activities against the highly metastatic human breast cancer cell line MDA-MB231 has been assessed. Ligstroside aglycone (2) showed the best antimigratory activity. Generally, tyrosol esters showed better activities versus carbamate analogues. Tyrosol sinapate (5) showed the best c-MET phosphorylation inhibitory activity in Z'-LYTE kinase assay. Both 1 and 5 competitively inhibited the ATP binding into its pocket in the c-MET catalytic domain. Compound 5 showed selective activities against tumor cells without toxicity to the non-tumorigenic human breast MCF10A epithelial cell line. Tyrosol esters with a phenolic acid containing hydrogen bond donor and/or acceptor groups at the para-position have better anticancer and c-MET inhibitory activities. Olive oil secoiridoids are excellent scaffolds for the design of novel c-MET inhibitors.

Subereamolline A as a potent breast cancer migration, invasion and proliferation inhibitor and bioactive dibrominated alkaloids from the Red Sea sponge Pseudoceratina arabica

A new collection of several Red Sea sponges was investigated for the discovery of potential breast cancer migration inhibitors. Extracts of the Verongid sponges Pseudoceratina arabica and Suberea mollis were selected. Bioassay-directed fractionation of both sponges, using the wound-healing assay, resulted into the isolation of several new and known brominated alkaloids. Active fractions of the sponge Pseudoceratina arabica afforded five new alkaloids, ceratinines A-E (2-6), together with the known alkaloids moloka'iamine (1), hydroxymoloka'iamine (7) and moloka'iakitamide (8). The active fraction of the sponge Suberea mollis afforded the three known alkaloids subereamolline A (9), aerothionin (10) and homoaerothionin (11). Ceratinine B (3) possesses an unprecedented 5,7-dibrominated dihydroindole moiety with an epoxy ring on the side chain of a fully substituted aromatic moiety. Ceratinines D (5) and E (6) possess a terminal formamide moiety at the ethylamine side chain. Subereamolline A (9) potently inhibited the migration and invasion of the highly metastatic human breast cancer cells MDA-MB-231 at the nanomolar doses. Subereamolline A and related brominated alkaloids are novel scaffolds appropriate for further future use for the control of metastatic breast cancer.

Semisynthetic analogues of the marine cembranoid sarcophine as prostate and breast cancer migration inhibitors

Sarcophine (1) is a bioactive cembranoid diterpene isolated from the Red Sea soft coral Sarcophyton glaucum. Previous semisynthesis attempts resulted in decreased or complete loss of 1's anticancer activity. Sarcophine and analogues showed antimigratory activity against breast and prostate cancer cell lines. This encouraged further semisynthestic optimizations to improve its activity and establish a preliminary structure-activity relationship. Eight new and five known semisynthetic analogues were generated. These compounds were evaluated for their ability to inhibit growth, proliferation, and migration of the prostate and breast metastatic cancer cell lines PC-3 and MDA-MB-231, respectively. Most analogues exhibited enhanced antimigratory activity.

Antimicrobial, antioxidant, and antimutagenic activities of selected marine natural products and tobacco cembranoids

Multidrug resistance (MDR) in microorganisms is a cause of major concern for clinicians and pharmaceutical industries. Continuous development of new antimicrobial drugs with multiple targets and potentials is expected to efficiently combat MDR in these microorganisms. In a continued exploration of new antimicrobial drug leads, 11 marine natural products, semisynthetic, or related synthetic analogs (1-11) and two tobacco cembranoids (12 and 13) were screened for their antimicrobial, antioxidant, and antimutagenic activities. Eight compounds showed varying levels of both antibacterial and antifungal activities. Compounds such as 17-O-methyllatrunculin-A, verongiaquinol, (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol), and manzamine-A showed a broad spectrum of activity, inhibiting six of seven tested bacteria with zone of inhibition diameter from 9 to 30 mm. Four of these active compounds also showed antifungal activity. The findings of the in vitro time-kill assay of the most active compound, verongiaquinol, against Staphylococcus aureus indicated its subinhibitory effect at the level lower than the minimal inhibitory concentration (MIC) values (i.e., 2 and 4 µg/mL). At the MIC (8 µg/mL), bacterial cells were completely killed within 18 hours of incubation. DPPH free radical scavenging activity was demonstrated by five compounds in the range of 89.65-36.19% decolorization. Further, four compounds evaluated for their antimutagenic activity against the directly acting mutagens, methyl methanesulfonate and sodium azide, in Salmonella typhimurium strains, interestingly, showed no sign of mutagenicity. Verongiaquinol and manzamine A, in fact, reduced the mutagenicity by 50-75% at a dose of 5 µg/plate in different test strains. Our study seems to provide some novel antimicrobial leads with strong antioxidant potential and the associated ability of antimutagenicity.

Methods for evaluation of structural and biological properties of antiinvasive natural products

Prostate cancer is considered the most common cancer form among males in Western countries. Very limited options are available for the treatment of advanced metastatic prostate cancer. More than 50% of today's anticancer drugs are natural products or derived from a natural origin. To discover new entities with potential to treat prostate cancer at androgen-refractory stages, 36 structurally diverse natural products were screened using functional-based assays. The tested compounds were selected broadly from major secondary metabolites of plants, marine invertebrates, and fungi. These diverse entities were prescreened for their antiinvasive ability against prostate cancer cells, PC-3M, using spheroid disaggregation assay. Active representatives including three selected structural classes, a macrolide, a β-carboline alkaloid, and a phenylmethylene hydantoin (PMH), were then tested for their ability to stabilize junctional complexes and enhance cell-cell adhesion of androgen independent prostate cancer cells. Transepithelial resistance (TER) and paracellular permeability assays were used to elicit the aforementioned properties. These studies led to the emergence of PMHs as a small molecule class from the marine sponge Hemimycale arabica with a unique potential to attenuate CT-stimulated prostate cancer growth, metastasis, paracellular permeability, and enhance TER and cell-cell adhesion of prostate cancer cells. The unique activities of PMHs were validated using several in vitro assays followed by in vivo testing in two mice models. A 3D QSAR was established using SYBYL 8.1-Comparative Molecular Field Analysis (CoMFA) model. This chapter includes the methodology for evaluation of structural and biological properties of new antiinvasive molecules with an exceptional potential to stabilize junctional complexes from diverse natural product sources.