Revolutionizing Rural Oncology: Innovative Models and Global Perspectives.

For individuals living in rural areas, access to cancer care can be difficult. Barriers to access cross international boundaries and have a negative impact on treatment outcomes. Current models to increase rural access in the United States are reviewed, as is a system-wide approach to this problem in Australia.

Prospective Comparison of Geriatric Assessment and Provider's Assessment of Older Adults With Metastatic Breast Cancer in the Community.

Background: Geriatric assessment (GA) is recommended for evaluating fitness of an older adult with cancer. Our objective was to prospectively evaluate the gaps that exist in the assessment of older adults with metastatic breast cancer (OA-MBC) in community practices (CP).

Methods: Self-administered GA was compared to provider's assessment (PA) of patients living with MBC aged ≥65 years treated in CP Providers were blinded to the GA results until PA was completed.

Hydrogels Containing Gradients in Vascular Density Reveal Dose-Dependent Role of Angiocrine Cues on Stem Cell Behavior.

Biomaterials that replicate patterns of microenvironmental signals from the stem cell niche offer the potential to refine platforms to regulate stem cell behavior. While significant emphasis has been placed on understanding the effects of biophysical and biochemical cues on stem cell fate, vascular-derived or angiocrine cues offer an important alternative signaling axis for biomaterial-based stem cell platforms. Elucidating dose-dependent relationships between angiocrine cues and stem cell fate are largely intractable in animal models and 2D cell cultures.

Analysis of eukaryotic translation in purified and semipurified systems.

Much of the current understanding of the sequential steps involved in translation initiation has been obtained using sucrose gradients to isolate ribosomes and ribosomal subunits, as described here. These purified components are combined with purified translation factors to analyze the formation of intermediates in translation initiation and the roles of the translation factors in vitro.

Novel characteristics of the biological properties of the yeast Saccharomyces cerevisiae eukaryotic initiation factor 2A.

Eukaryotic initiation factor 2A (eIF2A) has been shown to direct binding of the initiator methionyl-tRNA (Met-tRNA(i)) to 40 S ribosomal subunits in a codon-dependent manner, in contrast to eIF2, which requires GTP but not the AUG codon to bind initiator tRNA to 40 S subunits. We show here that yeast eIF2A genetically interacts with initiation factor eIF4E, suggesting that both proteins function in the same pathway. The double eIF2A/eIF4E-ts mutant strain displays a severe slow growth phenotype, which correlated with the accumulation of 85% of the double mutant cells arrested at the G(2)/M border.

15-Hydroxyprostaglandin dehydrogenase, a COX-2 oncogene antagonist, is a TGF-beta-induced suppressor of human gastrointestinal cancers.

Marked increased expression of cyclooxygenase 2 (COX-2), a prostaglandin-synthesizing enzyme that is pharmacologically inhibited by nonsteroid anti-inflammatory-type drugs, is a major early oncogenic event in the genesis of human colon neoplasia. We report that, in addition to inducing expression of COX-2, colon cancers further target the prostaglandin biogenesis pathway by ubiquitously abrogating expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a prostaglandin-degrading enzyme that physiologically antagonizes COX-2. We find that 15-PGDH transcript and protein are both highly expressed by normal colonic epithelia but are nearly undetectable in colon cancers.

p53-induced inhibition of protein synthesis is independent of apoptosis.

Activation of a temperature-sensitive form of p53 in murine erythroleukaemia cells results in a rapid impairment of protein synthesis that precedes inhibition of cell proliferation and loss of cell viability by several hours. The inhibition of translation is associated with specific cleavages of polypeptide chain initiation factors eIF4GI and eIF4B, a phenomenon previously observed in cells induced to undergo apoptosis in response to other stimuli. Although caspase activity is enhanced in the cells in which p53 is activated, both the effects on translation and the cleavages of the initiation factors are completely resistant to inhibition of caspase activity.

Loss of ypk1 function causes rapamycin sensitivity, inhibition of translation initiation and synthetic lethality in 14-3-3-deficient yeast.

14-3-3 proteins bind to phosphorylated proteins and regulate a variety of cellular activities as effectors of serine/threonine phosphorylation. To define processes requiring 14-3-3 function in yeast, mutants with increased sensitivity to reduced 14-3-3 protein levels were identified by synthetic lethal screening. One mutation was found to be allelic to YPK1, which encodes a Ser/Thr protein kinase.

p53 activation results in rapid dephosphorylation of the eIF4E-binding protein 4E-BP1, inhibition of ribosomal protein S6 kinase and inhibition of translation initiation.

p53 is an important regulator of cell cycle progression and apoptosis, and inactivation of p53 is associated with tumorigenesis. Although p53 exerts many of its effects through regulation of transcription, this protein is also found in association with ribosomes and several mRNAs have been identified that are translationally controlled in a p53-dependent manner. We have utilized murine erythroleukemic cells that express a temperature-sensitive p53 protein to determine whether p53 also functions at the level of translation.

Characterization of mammalian eIF2A and identification of the yeast homolog.

To begin the physical characterization of eukaryotic initiation factor (eIF) 2A, a translation initiation factor that binds Met-tRNA(i), tryptic peptides from rabbit reticulocyte eIF2A were analyzed to obtain amino acid sequence information. Sequences for 8 peptides were matched to three different expressed sequence tag clones. The sequence predicted for eIF2A is 585 amino acids.

S6 phosphorylation-independent pathways regulate translation of 5'-terminal oligopyrimidine tract-containing mRNAs in differentiating hematopoietic cells.

Synthesis of new ribosomes is an energy costly and thus highly regulated process. Ribosomal protein synthesis is controlled by regulating translation of the corresponding ribosomal protein (rp)mRNAs. In mammalian cells a 5'-terminal oligopyrimidine tract (TOP) is a conserved feature of these mRNAs that has been demonstrated to be essential for their translational regulation.

Regulation of internal ribosome entry site-mediated translation by eukaryotic initiation factor-2alpha phosphorylation and translation of a small upstream open reading frame.

Adaptation to amino acid deficiency is critical for cell survival. In yeast, this adaptation involves phosphorylation of the translation eukaryotic initiation factor (eIF) 2alpha by the kinase GCN2. This leads to the increased translation of the transcription factor GCN4, which in turn increases transcription of amino acid biosynthetic genes, at a time when expression of most genes decreases.

The carboxyl-terminal domain of the granulocyte colony-stimulating factor receptor uncouples ribosomal biogenesis from cell cycle progression in differentiating 32D myeloid cells.

Translational regulation plays an important role in development. In terminally differentiating cells a decrease in translation rate is common, although the regulatory mechanisms are unknown. We utilized 32Dcl3 myeloblast cells to investigate translational regulation during granulocyte colony-stimulating factor (G-CSF)-induced differentiation.

Bms1p, a novel GTP-binding protein, and the related Tsr1p are required for distinct steps of 40S ribosome biogenesis in yeast.

Bms1p and Tsr1p define a novel family of proteins required for synthesis of 40S ribosomal subunits in Saccharomyces cerevisiae. Both are essential and localize to the nucleolus. Tsr1p shares two extended regions of similarity with Bms1p, but the two proteins function at different steps in 40S ribosome maturation.

The yeast hsp70 homologue Ssa is required for translation and interacts with Sis1 and Pab1 on translating ribosomes.

The 70-kDa heat shock proteins are molecular chaperones that participate in a variety of cellular functions. This chaperone function is stimulated by interaction with hsp40 proteins. The Saccharomyces cerevisiae gene encoding the essential hsp40 homologue, SIS1, appears to function in translation initiation.

Further biochemical and kinetic characterization of human eukaryotic initiation factor 4H.

A cDNA encoding human eukaryotic initiation factor (eIF) 4H was subcloned into a bacterial expression plasmid for purification of recombinant protein. Recombinant human eIF4H (heIF4H) was purified to greater than 95% homogeneity and shown to have similar physical characteristics to eIF4H purified from rabbit reticulocyte lysate as described previously. Functional studies have revealed that recombinant heIF4H functions identically to rabbit eIF4H in stimulating protein synthesis, and the ATP hydrolysis and helicase activities of eIF4A.

Purification and characterization of a new eukaryotic protein translation factor. Eukaryotic initiation factor 4H.

A new protein with translational activity has been identified on the basis of its ability to stimulate translation in an in vitro globin synthesis assay deficient in eukaryotic initiation factor (eIF) 4B and eIF4F. This protein has been purified to greater than 80% homogeneity from rabbit reticulocyte lysate and has been given the name eIF4H. eIF4H was shown to stimulate the in vitro activities of eIF4B and eIF4F in globin synthesis, as well as the in vitro RNA-dependent ATPase activities of eIF4A, eIF4B, and eIF4F.

The conserved 5'-untranslated leader of Spi-1 (PU.1) mRNA is highly structured and potently inhibits translation in vitro but not in vivo.

The transcription factor Spi-1 (PU.1) has a central role in regulating myeloid gene expression during hematopoietic development and its overexpression has been implicated in erythroleukemic transformation. Thus regulation of Spi-1 expression has broad significance for hematopoietic development.

Inducers of erythroleukemic differentiation cause messenger RNAs that lack poly(A)-binding protein to accumulate in translationally inactive, salt-labile 80 S ribosomal complexes.

Translation has an established role in the regulation of cell growth. Posttranslational modification of translation initiation and elongation factors or regulation of mRNA polyadenylation represent common means of regulating translation in response to mitogenic or developmental signals. Induced differentiation of Friend virus-transformed erythroleukemia cells is accompanied by a rapid decrease in the translation rate of these cells.

RNA polymerase II inhibitor, 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) causes erythroleukemic differentiation and transcriptional activation of erythroid genes.

Friend virus-transformed murine erythroleukemia (MEL) cells are a useful system for studying the regulation of erythroid growth and differentiation. As a manifestation of the leukemic process, these erythroblasts are blocked in their ability to terminally differentiate. However, this block is reversible as a variety of different agents are capable of inducing differentiation of these malignant erythroblasts.

Expression of the transcription factor, Spi-1 (PU.1), in differentiating murine erythroleukemia cells Is regulated post-transcriptionally. Evidence for differential stability of transcription factor mRNAs following inducer exposure.

Increased expression of the transcription factor Spi-1 (PU.1) results from retroviral insertion in nearly all Friend spleen focus-forming virus-transformed murine erythroleukemia cell lines and exposure of these cells to Me2SO, induces their differentiation and decreases Spi-1 mRNA level by 4-5-fold. While these results suggest that alterations in Spi-1 expression have significant effects on erythroblast growth and differentiation, neither the cause nor the effect of the decrease in Spi-1 expression that follows Me2SO exposure has been established.

Mouse beta-globin DNA-binding protein B1 is identical to a proto-oncogene, the transcription factor Spi-1/PU.1, and is restricted in expression to hematopoietic cells and the testis.

The hematopoietic-specific DNA-binding protein B1 binds to the DNA consensus sequence AAAGRGGAARYG located twice in intervening sequence 2 of both of the mouse beta-globin genes (D. L. Galson and D.

Preferential synthesis of the 78-Kd glucose-regulated protein in glucocorticoid-treated S49 mouse lymphoma cells.

To investigate the mechanism of glucocorticoid-induced lymphocytolysis, we used two-dimensional gel electrophoresis to analyze the effect of dexamethasone on the synthesis of individual proteins in S49 mouse lymphoma cells. We found that synthesis of a 78-Kd protein is preferentially maintained following dexamethasone treatment, at a time when the synthesis of most other cellular proteins is decreased. Synthesis of this protein could also be induced by tunicamycin, suggesting that it might be the 78-Kd glucose-regulated protein (GRP78).

Calcium ionophore, A23187, induces commitment to differentiation but inhibits the subsequent expression of erythroid genes in murine erythroleukemia cells.

Murine erythroleukemia (MEL) cells are a useful model for studying the processes that regulate erythroid differentiation because exposure of these cells to a variety of chemical inducing agents results in expression of erythroid-specific genes and the resultant loss of cellular immortality. Previously it has been suggested that the calcium ionophore, A23187, has effects on the early cellular events that lead to the commitment of these cells to differentiation, but was not in itself sufficient to induce differentiation. We demonstrate here that A23187, as well as another calcium ionophore, ionomycin, are capable of inducing commitment to differentiation.