Creating chemotherapeutic-resistant breast cancer cell lines: advances and future perspectives.

The development of resistance remains the most significant impediment to generating effective treatments for cancer. In the modern age of personalized medicine, it is of critical importance to understand the principles of both innate and acquired resistance to achieve the most effective therapeutic outcomes. Significant differences exist between cancer cells that exhibit innate resistance verses those that acquire resistance over time. Studying the acquisition of resistance is essential to obtaining a complete understanding of how treatments contribute to disease recurrence and progression. This review will evaluate the current understanding of chemotherapeutic resistance and its role in personalized medicine. This review will also explore how generating resistant cells in culture is essential to the development of improved cancer therapeutics.

Pharmaceutical regulation of telomerase and its clinical potential.

Telomeres serve the dual function of protecting chromosomes from genomic instability as well as protecting the ends of chromosomes from DNA damage machinery. The enzyme responsible for telomere maintenance is telomerase, an enzyme capable of reverse transcription. Telomerase activity is typically limited to specific cell types. However, telomerase activation in somatic cells serves as a key step toward cell immortalization and cancer. Targeting telomerase serves as a potential cancer treatment with significant therapeutic benefits. Beyond targeting cancers by inhibiting telomerase, manipulating the regulation of telomerase may also provide therapeutic benefit to other ailments, such as those related to aging. This review will introduce human telomeres and telomerase and discuss pharmacological regulation of telomerase, including telomerase inhibitors and activators, and their use in human diseases.

The role of interleukin-12 on modulating myeloid-derived suppressor cells, increasing overall survival and reducing metastasis.

Myeloid-derived suppressor cells (MDSC) are important to the tumour microenvironment as they actively suppress the immune system and promote tumour progression and metastasis. These cells block T-cell activation in the tumour microenvironment, preventing anti-tumour immune activity. The ability of a treatment to alter the suppressive function of these cells and promote an immune response is essential to enhancing overall therapeutic efficacy. Interleukin-12 (IL-12) has the potential not only to promote anti-tumour immune responses but also to block the activity of cells capable of immune suppression. This paper identifies a novel role for IL-12 as a modulator of MDSC activity, with implications for IL-12 as a therapeutic agent. Treatment with IL-12 was found to alter the suppressive function of MDSC by fundamentally altering the cells. Interleukin-12-treated MDSC exhibited up-regulation of surface markers indicative of mature cells as well as decreases in nitric oxide synthase and interferon-γ mRNA both in vitro and in vivo. Treatment with IL-12 was also found to have significant therapeutic benefit by decreasing the percentage of MDSC in the tumour microenvironment and increasing the percentage of active CD8(+) T cells. Treatment with IL-12 resulted in an increase in overall survival accompanied by a reduction in metastasis. The findings in this paper identify IL-12 as a modulator of immune suppression with significant potential as a therapeutic agent for metastatic breast cancer.

Medical genetics and epigenetics of telomerase.

Telomerase is a specialized reverse transcriptase that extends and maintains the terminal ends of chromosomes, or telomeres. Since its discovery in 1985 by Nobel Laureates Elizabeth Blackburn and Carol Greider, thousands of articles have emerged detailing its significance in telomere function and cell survival. This review provides a current assessment on the importance of telomerase regulation and relates it in terms of medical genetics. In this review, we discuss the recent findings on telomerase regulation, focusing on epigenetics and non-coding RNAs regulation of telomerase, such as microRNAs and the recently discovered telomeric-repeat containing RNA transcripts. Human genetic disorders that develop due to mutations in telomerase subunits, the role of single nucleotide polymorphisms in genes encoding telomerase components and diseases as a result of telomerase regulation going awry are also discussed. Continual investigation of the complex regulation of telomerase will further our insight into the use of controlling telomerase activity in medicine.

Suppression of renal cell carcinoma growth and metastasis with sustained antiangiogenic gene therapy.

Renal cell carcinoma (RCC) is the third most common urologic neoplasm. This aggressive malignancy has proven refractory to conventional treatment options. Antiangiogenic agents have shown early success in treating metastatic disease. The highly vascular nature of RCC appears particularly susceptible to this approach. This study investigates the potential of sustained expression of an endostatin-angiostatin fusion protein in an early-stage model of RCC to inhibit tumor growth and metastasis. Subcutaneous RCC-29 tumors were induced in athymic nude mice. Once tumors reached volumes of 10 and 25 mm(3), subjects received intratumoral injections of a nonreplicating adenoviral vector every 20 days until the conclusion of the trial. The mice were randomly assigned to three treatment groups: saline control, viral Ad-GFP control, and Ad-EndoAngio. Tumor volumes were measured twice weekly for 80 days. During days 40-50 of the trial, subjects underwent dual-photon optical imaging of the tumor vasculature to ascertain angiogenic changes. All animals underwent postmortem histopathological analysis to assess for metastatic disease in the kidney, lung, liver, brain, and spleen. Results indicate that tumors treated with Ad-EndoAngio displayed 97% growth reduction compared with controls (p < 0.001). Further, in vivo tumor vascular imaging illustrated a reduction in blood vessel number and lumen diameter size. Kaplan-Meier analysis suggested dramatic survival advantage with Ad-EndoAngio treatment. Importantly, histopathological examination demonstrated marked lung and liver metastasis suppression in the treatment arms. These results suggest that sustained EndoAngio gene therapy has effective antiangiogenic action against human RCC tumors and possesses potential as a novel treatment for metastatic renal cell carcinoma.