The use of radiotherapy for early breast cancer in woman at different ages

Therapeutic Peptide RF16 Derived from CXCL8 Inhibits MDA-MB-231 Cell Invasion and Metastasis

Interleukin (IL)-8 plays a vital role in regulating inflammation and breast cancer formation by activating CXCR1/2. We previously designed an antagonist peptide, (RF16), to inhibits the activation of downstream signaling pathways by competing with IL-8 in binding to CXCR1/2, thereby inhibiting IL-8-induced chemoattractant monocyte binding. To evaluate the effect of the RF16 peptide on breast cancer progression, triple-negative MDA-MB-231 and ER-positive MCF-7 breast cancer cells were used to investigate whether RF16 can inhibit the IL-8-induced breast cancer metastasis. Using growth, proliferation, and invasiveness assays, the results revealed that RF16 reduced cell proliferation, migration, and invasiveness in MDA-MB-231 cells. The RF16 peptide also regulated the protein and mRNA expressions of epithelial-mesenchymal transition (EMT) markers in IL-8-stimulated MDA-MB-231 cells. It also inhibited downstream IL-8 signaling and the IL-8-induced inflammatory response via the mitogen-activated protein kinase (MAPK) and Phosphoinositide 3-kinase (PI3K) pathways. In the xenograft tumor mouse model, RF16 synergistically reinforces the antitumor efficacy of docetaxel by improving mouse survival and retarding tumor growth. Our results indicate that RF16 significantly inhibited IL-8-stimulated cell growth, migration, and invasion in MDA-MB-231 breast cancer cells by blocking the activation of p38 and AKT cascades. It indicated that the RF16 peptide may serve as a new supplementary drug for breast cancer.

Excess mortality from breast cancer in female breast cancer patients with severe mental illness

Women with a history of severe mental illness (SMI) have elevated breast cancer mortality. Few studies have compared cancer-specific mortality in women with breast cancer with or without SMI to reveal gaps in breast cancer treatment outcomes. We compared breast-cancer specific mortality in women with or without SMI and investigated effects of stage at presentation, comorbidity, and differences in cancer treatment. Women with their first breast cancer diagnosis in 1990-2013 (n = 80,671) were identified from the Finnish Cancer Registry, their preceding hospital admissions due to SMI (n = 4,837) from the Hospital Discharge Register and deaths from the Causes of Death Statistics. Competing risk models were used in statistical analysis. When controlling for age, year of cancer diagnosis, and comorbidity, breast cancer mortality was significantly elevated in patients with SMI. Relative mortality was highest in breast cancer patients with non-affective psychosis, partly explained by stage at presentation. Mortality was also significantly elevated in breast cancer patients with a substance use disorder and mood disorder. Patients with SMI received radiotherapy significantly less often than patients without SMI. Our findings emphasize the need to improve early detection of breast cancer in women with SMI and the collaboration between mental health care and oncological teams.

Studies on DNA Damage Repair and Precision Radiotherapy for Breast Cancer

Radiotherapy acts as an important component of breast cancer management, which significantly decreases local recurrence in patients treated with conservative surgery or with radical mastectomy. On the foundation of technological innovation of radiotherapy setting, precision radiotherapy of cancer has been widely applied in recent years. DNA damage and its repair mechanism are the vital factors which lead to the formation of tumor. Moreover, the status of DNA damage repair in cancer cells has been shown to influence patient response to the therapy, including radiotherapy. Some genes can affect the radiosensitivity of tumor cell by regulating the DNA damage repair pathway. This chapter will describe the potential application of DNA damage repair in precision radiotherapy of breast cancer.

Nelfinavir targets multiple drug resistance mechanisms to increase the efficacy of doxorubicin in MCF-7/Dox breast cancer cells

Development of multidrug resistance (MDR) remains a significant problem in cancer chemotherapy and underscores the importance of using chemosensitizers. Well known MDR mechanisms include: (i) upregulation of drug-efflux; (ii) increased signaling via AKT; and (iii) decreased apoptosis. Therefore, chemosensitizers should target multiple resistance mechanisms. We investigated the efficacy of nelfinavir (NFV), a clinically approved anti-HIV drug, in increasing doxorubicin (DOX) toxicity in a MDR breast cancer cell line, MCF-7/Dox. As compared to parental MCF-7 cells, the MCF-7/Dox were 15-20 fold more resistant to DOX-induced cytotoxicity at 48 h post-exposure (DOX IC50 = 1.8 μM vs. 32.4 μM). Coexposures to NFV could significantly (p < 0.05) decrease DOX-IC50 in MCF-7/Dox cells. Multiple exposures to physiologic concentrations of NFV (2.25 μM or 6.75 μM) decreased DOX-IC50 by 21-fold and 50-fold, respectively. Interestingly, although single exposure to NFV transiently induced P-glycoprotein (P-gp) levels, multiple treatments with NFV inhibited both P-gp expression and efflux function, which increased intracellular DOX concentrations. Single exposure to NFV augmented the markers of cell-survival (AKT) and autophagy (LC3-II), whereas multiple exposures enabled suppression of both total AKT (t-AKT) and insulin like growth factor-1 (IGF-1)-induced phosphorylated AKT (p-AKT) levels. Multiple exposures to NFV also resulted in increased unfolded protein response (UPR) transducers, e.g. Grp78, p-PERK, p-eIF2α, and ATF-4; and endoplasmic reticulum (ER) stress induced death sensors, e.g. CHOP & TRIB-3. Multiple exposures to NFV also abrogated the mitogenic effects of IGF-1. In mice carrying MCF-7/Dox tumor xenografts, intraperitoneal (i.p.) injection of NFV (20 mg/kg/day) and DOX (2 mg/kg/twice/wk) decreased tumor growth more significantly (p < 0.01) than either agent alone. Immunohistochemical (IHC) analysis revealed decreased p-AKT and Ki-67 levels. Thus, NFV overcomes MDR in breast cancer cells and should be tested as an adjunct to chemotherapy.

Subgroup Economic Evaluation of Radiotherapy for Breast Cancer After Mastectomy

BACKGROUND

A recent meta-analysis by the Early Breast Cancer Trialists' Collaborative Group found significant improvements achieved by postmastectomy radiotherapy (PMRT) for patients with breast cancer with 1 to 3 positive nodes (pN1-3). It is unclear whether PMRT is cost-effective for subgroups of patients with positive nodes.

OBJECTIVE

To determine the cost-effectiveness of PMRT for subgroups of patients with breast cancer with positive nodes.

METHODS

A semi-Markov model was constructed to estimate the expected lifetime costs, life expectancy, and quality-adjusted life-years for patients receiving or not receiving radiation therapy. Clinical and health utilities data were from meta-analyses by the Early Breast Cancer Trialists' Collaborative Group or randomized clinical trials. Costs were estimated from the perspective of the Chinese society. One-way and probabilistic sensitivity analyses were performed.

FINDINGS

The incremental cost-effective ratio was estimated as $7984, $4043, $3572, and $19,021 per quality-adjusted life-year for patients with positive nodes (pN+), patients with pN1-3, patients with pN1-3 who received systemic therapy, and patients with >4 positive nodes (pN4+), respectively. According to World Health Organization recommendations, these incremental cost-effective ratios were judged as cost-effective. However, the results of one-way sensitivity analyses suggested that the results were highly sensitive to the relative effectiveness of PMRT (rate ratio).

IMPLICATIONS

We determined that the results were highly sensitive to the rate ratio. However, the addition of PMRT for patients with pN1-3 in China has a reasonable chance to be cost-effective and may be judged as an efficient deployment of limited health resource, and the risk and uncertainty of PMRT are relatively greater for patients with pN4+.