Ecological and evolutionary dynamics to design and improve ovarian cancer treatment.

Ovarian cancer ecosystems are exceedingly complex, consisting of a high heterogeneity of cancer cells. Development of drugs such as poly ADP-ribose polymerase (PARP) inhibitors, targeted therapies and immunotherapies offer more options for sequential or combined treatments. Nevertheless, mortality in metastatic ovarian cancer patients remains high because cancer cells consistently develop resistance to single and combination therapies, urging a need for treatment designs that target the evolvability of cancer cells.

Lipophilicity Determines Routes of Uptake and Clearance, and Toxicity of an Alpha-Particle-Emitting Peptide Receptor Radiotherapy.

Lipophilicity is explored in the biodistribution (BD), pharmacokinetics (PK), radiation dosimetry (RD), and toxicity of an internally administered targeted alpha-particle therapy (TAT) under development for the treatment of metastatic melanoma. The TAT conjugate is comprised of the chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate), conjugated to melanocortin receptor 1 specific peptidic ligand (MC1RL) using a linker moiety and chelation of the Ac radiometal. A set of conjugates were prepared with a range of lipophilicities (log values) by varying the chemical properties of the linker.

Preclinical evaluation of [Ac]Ac-DOTA-TATE for treatment of lung neuroendocrine neoplasms.

Purpose: There is significant interest in the development of targeted alpha-particle therapies (TATs) for treatment of solid tumors. The metal chelator-peptide conjugate, DOTA-TATE, loaded with the β-particle emitting radionuclide Lu ([Lu]Lu-DOTA-TATE) is now standard care for neuroendocrine tumors that express the somatostatin receptor 2 (SSTR2) target. A recent clinical study demonstrated efficacy of the corresponding [Ac]Ac-DOTA-TATE in patients that were refractory to [Lu]Lu-DOTA-TATE.

Biodistribution and Multicompartment Pharmacokinetic Analysis of a Targeted α Particle Therapy.

Targeted α particle therapy (TAT) is ideal for treating disease while minimizing damage to surrounding nontargeted tissues due to short path length and high linear energy transfer (LET). We developed a TAT for metastatic uveal melanoma, targeting the melanocortin-1 receptor (MC1R), which is expressed in 94% of uveal melanomas. Two versions of the therapy are being investigated: Ac-DOTA-Ahx-MC1RL (Ac-Ahx) and Ac-DOTA-di-d-Glu-MC1RL (Ac-di-d-Glu).

Narrowing the focus: Therapeutic cell surface targets for refractory triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is defined as a type of breast cancer with lack of expression of estrogen receptor, progesterone receptor and human epidermal growth factor 2 protein. In comparison to other types of breast cancer, TNBC characterizes for its aggressive behavior, more prone to early recurrence and a disease with poor response to molecular target therapy. Although TNBC is identified in only 25%-30% of American breast cancer cases annually, these tumors continue to be a therapeutic challenge for clinicians for several reasons: Tumor heterogeneity, limited and toxic systemic therapy options, and often resistance to current standard therapy, characterized by progressive disease on treatment, residual tumor after cytotoxic chemotherapy, and early recurrence after complete surgical excision.

Development of Targeted Alpha Particle Therapy for Solid Tumors.

Targeted alpha-particle therapy (TAT) aims to selectively deliver radionuclides emitting α-particles (cytotoxic payload) to tumors by chelation to monoclonal antibodies, peptides or small molecules that recognize tumor-associated antigens or cell-surface receptors. Because of the high linear energy transfer (LET) and short range of alpha (α) particles in tissue, cancer cells can be significantly damaged while causing minimal toxicity to surrounding healthy cells. Recent clinical studies have demonstrated the remarkable efficacy of TAT in the treatment of metastatic, castration-resistant prostate cancer.

Melanocortin 1 Receptor-Targeted α-Particle Therapy for Metastatic Uveal Melanoma.

New effective therapies are greatly needed for metastatic uveal melanoma, which has a very poor prognosis with a median survival of less than 1 y. The melanocortin 1 receptor (MC1R) is expressed in 94% of uveal melanoma metastases, and a MC1R-specific ligand (MC1RL) with high affinity and selectivity for MC1R was previously developed. The Ac-DOTA-MC1RL conjugate was synthesized in high radiochemical yield and purity and was tested in vitro for biostability and for MC1R-specific cytotoxicity in uveal melanoma cells, and the lanthanum-DOTA-MC1RL analog was tested for binding affinity.

Chronic acidosis in the tumour microenvironment selects for overexpression of LAMP2 in the plasma membrane.

Early cancers are avascular and hence, profoundly acidic. Pre-malignant cells must adapt to acidosis to thrive in this hostile microenvironment. Here, we investigate MCF-7 cells that are adapted to grow in acidic conditions using SILAC proteomics and we reveal a significant upregulation of lysosomal proteins.

Evaluation of CAIX and CAXII Expression in Breast Cancer at Varied O2 Levels: CAIX is the Superior Surrogate Imaging Biomarker of Tumor Hypoxia.

Purpose: Hypoxia is commonly observed in regions of primary tumors and metastases, and is associated with resistance to treatment, more aggressive tumor phenotypes and poor prognosis. Reliable and validated imaging biomarkers of hypoxia are needed for pre-clinical studies and clinical use. Expression of cell-surface carbonic anhydrases IX and XII (CAIX and CAXII) in tumor cells has been associated with tumor hypoxia.

The role of toll-like receptors in colorectal cancer progression: evidence for epithelial to leucocytic transition.

Toll-like receptors (TLRs) are expressed by immune cells, intestinal epithelium, and tumor cells. In the homeostatic setting, they help to regulate control over invading pathogens and maintain the epithelial lining of the large and small intestines. Aberrant expression of certain TLRs by tumor cells can induce growth inhibition while others contribute to tumorigenesis and progression.

Carbonic anhydrase IX as an imaging and therapeutic target for tumors and metastases.

Carbonic anhydrase IX (CAIX) which is a zinc containing metalloprotein, efficiently catalyzes the reversible hydration of carbon dioxide. It is constitutively up-regulated in several cancer types and has an important role in tumor progression, acidification and metastasis. High expression of CAIX generally correlates with poor prognosis and is related to a decrease in the disease-free interval following successful therapy.

Synthesis and characterization of time-resolved fluorescence probes for evaluation of competitive binding to melanocortin receptors.

Probes for use in time-resolved fluorescence competitive binding assays at melanocortin receptors based on the parental ligands MSH(4), MSH(7), and NDP-α-MSH were prepared by solid phase synthesis methods, purified, and characterized. The saturation binding of these probes was studied using HEK-293 cells engineered to overexpress the human melanocortin 4 receptor (hMC4R) as well as the human cholecystokinin 2 receptor (hCCK2R). The ratios of non-specific binding to total binding approached unity at high concentrations for each probe.

In vivo and in silico pharmacokinetics and biodistribution of a melanocortin receptor 1 targeted agent in preclinical models of melanoma.

The melanocortin 1 receptor (MC1R) is overexpressed in most melanoma metastases, making it a promising target for imaging of melanomas. In this study, the expression of MC1R in a large fraction of patients with melanoma was confirmed using mRNA and tissue microarray. Here, we have characterized the in vivo tumor and tissue distribution and pharmacokinetics (PK) of uptake and clearance of a MC1R specific peptidomimetic ligand conjugated to a near-infrared fluorescent dye.

Synthesis and characterization of a melanoma-targeted fluorescence imaging probe by conjugation of a melanocortin 1 receptor (MC1R) specific ligand.

The incidence of malignant melanoma is rising more rapidly than that of any other cancer in the United States. The melanocortin 1 receptor (MC1R) is overexpressed in most human melanoma metastases, thus making it a promising target for imaging and therapy of melanomas. We have previously reported the development of a peptidomimetic ligand with high specificity and affinity for MC1R.

Noninvasive detection of breast cancer lymph node metastasis using carbonic anhydrases IX and XII targeted imaging probes.

Purpose: To develop targeted molecular imaging probes for the noninvasive detection of breast cancer lymph node metastasis.

Experimental Design: Six cell surface or secreted markers were identified by expression profiling and from the literature as being highly expressed in breast cancer lymph node metastases. Two of these markers were cell surface carbonic anhydrase isozymes (CAIX and/or CAXII) and were validated for protein expression by immunohistochemistry of patient tissue samples on a breast cancer tissue microarray containing 47 normal breast tissue samples, 42 ductal carcinoma in situ, 43 invasive ductal carcinomas without metastasis, 46 invasive ductal carcinomas with metastasis, and 49 lymph node macrometastases of breast carcinoma.

Development of melanoma-targeted polymer micelles by conjugation of a melanocortin 1 receptor (MC1R) specific ligand.

The incidence of malignant melanoma is rising faster than that of any other cancer in the United States. Because of its high expression on the surface of melanomas, MC1R has been investigated as a target for selective imaging and therapeutic agents against melanoma. Eight ligands were screened against cell lines engineered to overexpress MC1R, MC4R, or MC5R.

A sucrose-derived scaffold for multimerization of bioactive peptides.

A spherical molecular scaffold bearing eight terminal alkyne groups was synthesized in one step from sucrose. One or more copies of a tetrapeptide azide, either N(3)(CH(2))(5)(CO)-His-DPhe-Arg-Trp-NH(2) (MSH4) or N(3)(CH(2))(5)(CO)-Trp-Met-Asp-Phe-NH(2) (CCK4), were attached to the scaffold via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Competitive binding assays using Eu-labeled probes based on the superpotent ligands Ser-Tyr-Ser-Nle-Glu-His-DPhe-Arg-Trp-Gly-Lys-Pro-Val-NH(2) (NDP-α-MSH) and Asp-Tyr-Met-Gly-Trp-Met-Asp-Phe-NH(2) (CCK8) were used to study the interactions of monovalent and multivalent MSH4 and CCK4 constructs with Hek293 cells engineered to overexpress MC4R and CCK2R.

A mammaglobin-A targeting agent for noninvasive detection of breast cancer metastasis in lymph nodes.

Pathologic axillary lymph node (ALN) status is an important prognostic factor for staging breast cancer. Currently, status is determined by histopathology following surgical excision of sentinel lymph node(s), which is an invasive, time consuming, and costly procedure with potential morbidity to the patient. Here, we describe an imaging platform for noninvasive assessment of ALN status, eliminating the need for surgical examination of patients to rule out nodal involvement.

Molecular and functional imaging of breast cancer.

Background: Significant efforts have been directed toward developing and enhancing imaging methods for the early detection, diagnosis, and characterization of small breast tumors. Molecular and functional imaging sets the stage for enhancement of current methodology.

Methods: Current imaging modalities are described based on the molecular characteristics of normal and malignant tissue.

Identification of novel pancreatic adenocarcinoma cell-surface targets by gene expression profiling and tissue microarray.

Pancreatic cancer has a high mortality rate, which is generally related to the initial diagnosis coming at late stage disease combined with a lack of effective treatment options. Novel agents that selectively detect pancreatic cancer have potential for use in the molecular imaging of cancer, allowing for non-invasive determination of tumor therapeutic response and molecular characterization of the disease. Such agents may also be used for the targeted delivery of therapy to tumor cells while decreasing systemic effects.

Targeting enteroviral 2A protease by a 16-mer synthetic peptide: inhibition of 2Apro-induced apoptosis in a stable Tet-on HeLa cell line.

Enteroviridae such as coxsackievirus are important infectious agents causing viral heart diseases. Viral protease 2A (2Apro) initiates the virus life cycle, and is an excellent target for developing antiviral drugs. Here, to evaluate the validity of the 2Apro as a proper therapeutic target, and based on the existing information and molecular dynamics, a 16-mer peptide was designed to specifically target the active site of protease 2Apro in order to block the activity of CVB3 2Apro.

Site-directed mutagenesis of firefly luciferase: implication of conserved residue(s) in bioluminescence emission spectra among firefly luciferases.

The bioluminescence colours of firefly luciferases are determined by assay conditions and luciferase structure. Owing to red light having lower energy than green light and being less absorbed by biological tissues, red-emitting luciferases have been considered as useful reporters in imaging technology. A set of red-emitting mutants of Lampyris turkestanicus (Iranian firefly) luciferase has been made by site-directed mutagenesis.

The influence of insertion of a critical residue (Arg356) in structure and bioluminescence spectra of firefly luciferase.

The firefly bioluminescence reaction, which uses luciferin, Mg-ATP, and molecular oxygen to yield an electronically excited oxyluciferin, is carried out by luciferase and visible light is emitted. The bioluminescence color of firefly luciferases is determined by the luciferase structure and assay conditions. Among different beetle luciferases, those from Phrixothrix railroad worm emit either yellow or red bioluminescence colors.

Development of a multiplex nested consensus PCR for detection and identification of major human herpesviruses in CNS infections.

Background: Rapid, sensitive and economical detection and identification of human herpesviruses as causative agents of central nervous system (CNS) infections are of clinical importance. The traditional methods for the detection of herpesviruses in CNS infections all suffer from limitations. PCR has a potential to overcome each of them.