Novel Peptide Therapeutic Approaches for Cancer Treatment.

Peptides are increasingly being developed for use as therapeutics to treat many ailments, including cancer. Therapeutic peptides have the advantages of target specificity and low toxicity. The anticancer effects of a peptide can be the direct result of the peptide binding its intended target, or the peptide may be conjugated to a chemotherapy drug or radionuclide and used to target the agent to cancer cells.

A Quantitative Analysis of Surgical Smoke Exposure as an Occupational Hazard.

Objective: We hypothesized that OR airborne PM was different in quantity and mutagenic potential than office air and cigarette smoke.

Summary Of Background Data: Exposure to surgical smoke has been equated to cigarette smoking and thought to be hazardous to health care workers despite limited data.

Methods: PM was measured during 15 operations in ORs with 24.

Molecular Targeting of Cancer-Associated PCNA Interactions in Pancreatic Ductal Adenocarcinoma Using a Cell-Penetrating Peptide.

Pancreatic ductal adenocarcinoma is a particularly difficult cancer to treat due to a lack of effective screening or treatment. Pancreatic cancer cells exhibit high proliferating cell nuclear antigen (PCNA) expression, which is associated with poor prognosis. PCNA, an important nuclear DNA replication and repair protein, regulates a myriad of proteins via the interdomain connector loop.

The Anticancer Activity of a First-in-class Small-molecule Targeting PCNA.

Purpose: Proliferating cell nuclear antigen (PCNA) plays an essential role in regulating DNA synthesis and repair and is indispensable to cancer cell growth and survival. We previously reported a novel cancer associated PCNA isoform (dubbed caPCNA), which was ubiquitously expressed in a broad range of cancer cells and tumor tissues, but not significantly in nonmalignant cells. We found the L126-Y133 region of caPCNA is structurally altered and more accessible to protein-protein interaction.

Partial Purification of a Megadalton DNA Replication Complex by Free Flow Electrophoresis.

We describe a gentle and rapid method to purify the intact multiprotein DNA replication complex using free flow electrophoresis (FFE). In particular, we applied FFE to purify the human cell DNA synthesome, which is a multiprotein complex that is fully competent to carry-out all phases of the DNA replication process in vitro using a plasmid containing the simian virus 40 (SV40) origin of DNA replication and the viral large tumor antigen (T-antigen) protein. The isolated native DNA synthesome can be of use in studying the mechanism by which mammalian DNA replication is carried-out and how anti-cancer drugs disrupt the DNA replication or repair process.

The Mechanism by Which MYCN Amplification Confers an Enhanced Sensitivity to a PCNA-Derived Cell Permeable Peptide in Neuroblastoma Cells.

Dysregulated expression of MYC family genes is a hallmark of many malignancies. Unfortunately, these proteins are not amenable to blockade by small molecules or protein-based therapeutic agents. Therefore, we must find alternative approaches to target MYC-driven cancers.

Expression of a novel peptide derived from PCNA damages DNA and reverses cisplatin resistance.

Background: An 8 amino acid peptide sequence derived from proliferating cell nuclear antigen (PCNA) has been shown to effectively kill several breast cancer and neuroblastoma cell lines when added exogenously to cell cultures.

Methods: In this study, the expression of the 8 amino acid peptide sequence (caPeptide) was placed under control of a tetracycline responsive promoter in MDA-MB-231 cells.

Results: Endogenous expression of the peptide resulted in an increase in genomic DNA damage.

CRM1 mediates nuclear-cytoplasmic shuttling of mature microRNAs.

Drosha-processed microRNAs (miRNAs) have been shown to be exported from the nucleus to the cytoplasm by Exportin 5, where they are processed a second time to generate mature miRNAs. In this work we show that miRNAs also use CRM1 for nuclear-cytoplasmic shuttling. Inhibition of CRM1 by Leptomycin B results in nuclear accumulation of miRNA guide sequences.

Combinatorial delivery of small interfering RNAs reduces RNAi efficacy by selective incorporation into RISC.

Despite the great potential of RNAi, ectopic expression of shRNA or siRNAs holds the inherent risk of competition for critical RNAi components, thus altering the regulatory functions of some cellular microRNAs. In addition, specific siRNA sequences can potentially hinder incorporation of other siRNAs when used in a combinatorial approach. We show that both synthetic siRNAs and expressed shRNAs compete against each other and with the endogenous microRNAs for transport and for incorporation into the RNA induced silencing complex (RISC).

MDR1 bicistronic vectors: analysis of selection stringency, amplified gene expression, and vector stability in cell lines.

The human multidrug resistance-1 gene (MDR1) is a dominant selectable and amplifiable marker in mammalian tissue culture cells. MDR1 is also being investigated as a gene therapy tool, both to protect normal cells against chemotherapy-related toxicity and to serve as an in vivo selectable marker for the overexpression of non-selectable therapeutic genes. The success of these strategies will depend on whether MDR1 expression can be sustained at levels high enough to confer a survival advantage on target cells.

Experiments on movement of DNA regions in Escherichia coli evaluated by computer simulation.

During the cell cycle of Escherichia coli DNA is replicated and segregated over two prospective daughter cells. Nucleoids as a whole separate gradually in line with cell elongation, but sub-nucleoid DNA regions may behave differently, separating non-gradually. We tested the ability of three models to predict the outcome of a fluorescent in situ hybridisation (FISH) experiment.

Effect of carbohydrate position on lysosomal transport of procathepsin L.

To study the role of carbohydrate in lysosomal protein transport, we engineered two novel glycosylation signals (Asn-X-Ser/Thr) into the cDNA of human procathepsin L, a lysosomal acid protease. We constructed six mutant cDNAs encoding glycosylation signals at mutant sites Asn-138, Asn-175, or both sites together, in the presence or absence of the wild-type Asn-204 site. We stably transfected wild-type and mutant cDNAs into NIH3T3 mouse fibroblasts and then used species-specific antibodies to determine the glycosylation status, phosphorylation, localization, and transport kinetics of recombinant human procathepsin L containing one, two, or three glycosylation sites.

Hypermethylation of telomere-like foldbacks at codon 12 of the human c-Ha-ras gene and the trinucleotide repeat of the FMR-1 gene of fragile X.

Runs of G residues on the G-rich strands of 30mers from the region spanning codon 12 of c-Ha-ras appear to be protected against chemical modification by dimethylsulfate. This suggests that the G-rich strand might spontaneously form a Hoogsteen-paired quadruplex, which is characteristic of telomere-like DNA sequences. In this report we show that the predominant species in 1:1 mixtures of complementary 30mers from this region are duplex DNA and a smaller amount of unimolecular foldback formed by the C-rich strand.

Zygote formation in the homothallic green alga Chlamydomonas monoica Strehlow.

Mating between cells of opposite mating type within a clonal population of Chlamydomonas monoica results in thick-walled zygotes. Zygote formation was studied in cells from continuous cultures fed with culture medium containing nitrate concentrations sufficient or limiting for growth. The factors that were considered were cell density and nitrate content of the medium.

Recognition of foldback DNA by the human DNA (cytosine-5-)-methyltransferase.

In order to specify the recognition requirements of the human DNA (cytosine-5-)-methyltransferase, two isomeric 48mers were synthesized so as to link a long block of DNA with a shorter complementary block of DNA through a tether consisting of five thymidine residues. These isomeric foldback molecules, differing only in the location of the 5-methyldeoxycytosine, were shown to be unimolecular, to contain a region of duplex DNA, and to contain a region of single-stranded DNA. When used as substrates for the DNA methyltransferase, only one of the isomers was methylated.

Quadruplex DNA formation in a region of the tRNA gene supF associated with hydrogen peroxide mediated mutations.

A hot spot for H2O2/Fe-mediated mutation has been observed between bases 154 and 170 of the supF gene in the mutation reporter plasmid pZ189 [Moraes et al. (1990) Carcinogenesis 11, 283; Akman et al. (1991) Mutat.

Prosthetic and surgical management of osteogenic sarcoma of the maxilla.

Maxillary surgical defects resulting from resection of oral neoplasms vary in size from small perforations of the hard and soft palate to complete removal of these structures. Osteogenic sarcoma is of unknown etiology and is a rapidly growing tumor that may produce pain, paresthesia, and anesthesia. The recommended treatment of radical resection often results in defects that produce significant orofacial disfigurement.

Cancer of the scalp.

Carcinomas on the scalp have a tendency to recur following traditional treatment. Their management is often difficult because of the extent of the tumor and the unique anatomy of the area. In order to maximize cure rates for complicated carcinomas, Mohs micrographic surgeons and other surgical specialists have formed interdisciplinary treatment teams.

Merkel cell carcinoma.

Merkel cell carcinoma is an unusual primary cutaneous tumor with an aggressive biologic nature. Following surgical treatment, 40% of patients have local recurrences develop, 55% have regional lymph node metastases develop, and 49% have distant metastases develop. We have treated four patients with Merkel cell carcinoma; only one of the four patients was alive and well after 2 years.

Cable grafting of the spinal accessory nerve for rehabilitation of shoulder function after radical neck dissection.

From January 1981 through December 1985, 9 patients underwent radical neck dissection with sacrifice of the spinal accessory nerve for removal of metastatic cancer to cervical nodes followed by reconstruction of the spinal accessory nerve utilizing a cable graft from the greater auricular nerve. Shoulder function on the operated side was assessed postoperatively using a subjective questionnaire, objective strength testing, and EMG recordings. The group that had cable grafts of the spinal accessory nerve were compared to a group who had modified radical neck dissection with preservation of the spinal accessory nerve, and to a third group that had classical radical neck dissection with sacrifice of the spinal accessory nerve and no cable graft reconstruction.

Modified neck dissection for metastatic testicular carcinoma.

Carcinoma of the testicle is a unique clinicopathologic entity in that an optimistic attitude toward cure can be entertained even in the presence of distant metastasis. Chemotherapy, followed by an aggressive surgical resection of residual disease, can result in eradication of this neoplasm. This tumor is capable of being monitored by the use of serum markers, namely, human chorionic gonadotropin and alpha-fetoprotein.

Extranodal lymphoma of the head and neck area.

Records of 64 patients with extranodal lymphoma of the head and neck area treated at this institution between 1965 and 1982 have been reviewed. Of these cases, 78% had Stage I-EA disease, 20% had Stage II-EA disease, and 2% had Stage III-EA disease. Excluded from this study were patients of the pediatric age, patients with previous chemotherapy and surgery, patients in whom extranodal involvement has been a terminal manifestation of wide-spread disease, and patients with nodal involvement with extension of disease outside the lymph nodes.