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Perspective on This Article from Metformin Prevents Liver Tumorigenesis by Inhibiting Pathways Driving Hepatic Lipogenesis

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PDF file - 148K, Supplemental Figure 3: RT-PCR analysis of Her-2 mRNA levels in MCF-7Ca and LTLT-Ca cells.

PDF file - 157K, Supplemental Figure 2: Western blotting analysis of LTLT-Ca cells treated with entinostat in presence of MG-132.

We previously showed that in innately resistant tumors, silencing of the estrogen receptor (ER) could be reversed by treatment with a histone deacetylase (HDAC) inhibitor, entinostat. Tumors were then responsive to aromatase inhibitor (AI) letrozole. Here, we investigated whether ER in the acquired letrozole-resistant tumors could be restored with entinostat. Ovariectomized athymic mice were inoculated with MCF-7Ca cells, supplemented with androstenedione (Δ4A), the aromatizable substrate. When the tumors reached about 300 mm3, the mice were treated with letrozole. After initial response to letrozole, the tumors eventually became resistant (doubled their initial volume). The mice then were grouped to receive letrozole, exemestane (250 μg/d), entinostat (50 μg/d), or the combination of entinostat with letrozole or exemestane for 26 weeks. The growth rates of tumors of mice treated with the combination of entinostat with letrozole or exemestane were significantly slower than with the single agent (P < 0.05). Analysis of the letrozole-resistant tumors showed entinostat increased ERα expression and aromatase activity but downregulated Her-2, p-Her-2, p-MAPK, and p-Akt. However, the mechanism of action of entinostat in reversing acquired resistance did not involve epigenetic silencing but rather included posttranslational as well as transcriptional modulation of Her-2. Entinostat treatment reduced the association of the Her-2 protein with HSP-90, possibly by reducing the stability of Her-2 protein. In addition, entinostat also reduced Her-2 mRNA levels and its stability. Our results suggest that the HDAC inhibitor may reverse letrozole resistance in cells and tumors by modulating Her-2 expression and activity. Mol Cancer Ther; 12(12); 2804–16. ©2013 AACR.

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PDF file - 40K, Supplemental Table 1. Selected Demographic and Baseline Characteristics of the Patients. Supplemental Table 2. Selected Demographic and Baseline Characteristics of the HPV16 positive.

Supplementary Figure Legends.

Supplementary Figure S2. K40R α-tubulin does not affect proliferation in MDA-MB-231 or BT-549 cells but decreases McTN frequency under transient transfection conditions.

Supplementary Table S1. Patient characteristics for survival analysis.

Metastatic cases of breast cancer pose the primary challenge in clinical management of this disease, demanding the identification of effective therapeutic strategies that remain wanting. In this study, we report that elevated levels of α-tubulin acetylation are a sufficient cause of metastatic potential in breast cancer. In suspended cell culture conditions, metastatic breast cancer cells exhibited high α-tubulin acetylation levels that extended along microtentacle (McTN) protrusions. Mutation of the acetylation site on α-tubulin and enzymatic modulation of this posttranslational modification exerted a significant impact on McTN frequency and the reattachment of suspended tumor cells. Reducing α-tubulin acetylation significantly inhibited migration but did not affect proliferation. In an analysis of more than 140 matched primary and metastatic tumors from patients, we found that acetylation was maintained and in many cases increased in lymph node metastases compared with primary tumors. Proteomic analysis of an independent cohort of more than 390 patient specimens further documented the relationship between increased α-tubulin acetylation and the aggressive behaviors of basal-like breast cancers, with a trend toward increased risk of disease progression and death in patients with high-intensity α-tubulin acetylation in primary tumors. Taken together, our results identify a tight correlation between acetylated α-tubulin levels and aggressive metastatic behavior in breast cancer, with potential implications for the definition of a simple prognostic biomarker in patients with breast cancer. Cancer Res; 75(1); 203–15. ©2014 AACR.

The best chemoradiation regimen to treat locally and regionally advanced head and neck squamous cell carcinoma (HNSCC) is yet to be established.We compared overall survival (OS) and adverse events following chemoradiation regimens (high-dose [HDC] or low-dose [LDC] cisplatin, or carboplatin [CB]) in HNSCC cases selected from SEER-Medicare linked database.Of the 1335 cases who underwent radiotherapy, 264 received HDC, 259 received LDC, and 353 received CB, concurrently. Compared to chemoradiation with HDC, using LDC or CB, or radiotherapy alone were associated with an increasingly worse OS; hazard ratios were 1.33, p = 0.03; 1.35, p = 0.02; and 2.12, p 0.001; respectively. There were no differences in the rates of adverse events between the three chemoradiation regimens.Chemoradiation regimen using HDC appears to be the best primary treatment for locally and regionally advanced HNSCC. Nonetheless, prospective large studies are warranted to further determine its absolute benefit.

Racial disparity in the incidence of multiple myeloma is well established; however, to the authors' knowledge, little is known regarding the impact of racial differences on disease characteristics, response to therapy, and clinical outcome.The authors studied 453 patients (174 of whom were black and 279 of whom were white) who underwent transplant between 2000 and 2013. The median follow-up was 4.4 years.Black patients were significantly younger than white patients (median age, 54 years vs 59 years; P.0001), more frequently presented with anemia (P = .04), had more of the immunoglobulin G isotype (P.001), and had a borderline favorable cytogenetic risk (P = .06). Overall response to induction was similar, but deeper responses were observed in more white patients compared with black patients receiving immunomodulatory drug-based induction (P = .02). Referral for transplant was significantly delayed in black individuals (median, 1.3 years vs 0.9 years; P = .003). Overall survival from the time of transplant was similar for black and white patients, with medians of 6.2 years and 5.7 years, respectively, but survival from the time of diagnosis was significantly longer among black individuals (median, 7.7 years vs 6.1 years; P = .03). Maintenance therapy was found to positively impact progression-free survival but not overall survival, irrespective of race.The results of the current study confirm ethnic differences in age, referral patterns, response to therapy, and overall survival. Future validation of these disparities is urgently needed.

Chemotherapy is frequently used in the treatment of advanced breast cancer. The identification of patient-specific tumor characteristics that can improve the ability to predict response to chemotherapy would help optimize advanced breast cancer treatment approaches. Quantitative immunofluorescence (QIF) may be applied to the standardization of protein analysis, resulting in increased sensitivity and reproducibility. In the current pilot study, QIF was used to correlate the expression of beta tubulin III and thymidylate synthase with clinical outcome associated with taxane and capecitabine treatment, respectively. QIF analysis is based on fluorescent dye-labeled monoclonal antibody staining followed by computer-assisted microscopy to measure the expression of molecular markers in tumor samples derived from a retrospective database. The interpretation of the tumor marker expression levels results in classification of breast tumors as sensitive or resistant to a mechanistically related drug. Overall diagnostic accuracy of QIF for taxane based therapy was 88% (CI 75.0 - 95.3) with a positive predictive value of 86% and a negative predictive value of 100%, while diagnostic accuracy QIF for capecitabine therapy was 86% (CI 88.0-96.0) with a positive predictive value of 80% and a negative predictive value of 100%. In this study, QIF showed retrospectively a potential for predictive value when analyzing chemotherapeutic treatments for individual advanced stage breast cancer patients. The predictive power of the QIF for chemotherapy confirms that further studies utilizing larger clinical cohorts are warranted.

Although the aromatase inhibitor anastrozole has been shown to be very effective in the treatment of hormone-dependent postmenopausal breast cancer, some patients with advanced disease will develop resistance to treatment. To investigate therapeutic strategies to overcome resistance to anastrozole treatment, we have used an intratumoral aromatase model that simulates postmenopausal breast cancer patients with estrogen-dependent tumors. Growth of the tumors in the mice was inhibited by both anastrozole and fulvestrant compared with the control tumors. Nevertheless, tumors had doubled in size at 5 weeks of treatment. We therefore investigated whether switching the original treatments to anastrozole or fulvestrant alone or the combination of anastrozole plus fulvestrant would reduce tumor growth. The results showed that the best strategy to reverse the insensitivity to anastrozole or fulvestrant is to combine the two agents. Additionally, the tumors treated with anastrozole plus fulvestrant from the beginning had only just doubled their size after 14 weeks of treatment, whereas the anastrozole and fulvestrant treatments alone resulted in 9- and 12-fold increases in tumor size, respectively, in the same time period. Anastrozole plus fulvestrant from the beginning or in sequence was associated with down-regulation of signaling proteins involved in the development of hormonal resistance such as insulin-like growth factor type I receptor β, mitogen-activated protein kinase (MAPK), p-MAPK, AKT, mammalian target of rapamycin (mTOR), p-mTOR, and estrogen receptor α compared with tumors treated with anastrozole or fulvestrant alone. These results suggest that blocking the estrogen receptor and aromatase may delay or reverse the development of resistance to aromatase inhibitors in advanced breast cancer patients. [Cancer Res 2008;68(9):3516–22]