Methylome Variation Predicts Exemestane Resistance in Advanced ER+ Breast Cancer.

BACKGROUND: More than 30% of estrogen receptor-positive breast cancers are resistant to primary hormone therapy, and about 40% that initially respond to hormone therapy eventually acquire resistance. Although the mechanisms of hormone therapy resistance remain unclear, aberrant DNA methylation has been implicated in oncogenesis and drug resistance. PURPOSE: We investigated the relationship between methylome variations in circulating tumor DNA and exemestane resistance, to track hormone therapy efficacy. METHODS: We prospectively recruited 16 patients who were receiving first-line therapy in our center. All patients received exemestane-based hormone therapy after enrollment. We collected blood samples at baseline, first follow-up (after 2 therapeutic cycles) and at detection of disease progression. Disease that progressed within 6 months under exemestane treatment was considered exemestane resistance but was considered relatively exemestane-sensitive otherwise. We obtained circulating tumor DNA-derived methylomes using the whole-genome bisulfide sequencing method. Methylation calling was done by BISMARK software; differentially methylated regions for exemestane resistance were calculated afterward. RESULTS: Median follow-up for the 16 patients was 19.0 months. We found 7 exemestane resistance-related differentially methylated regions, located in different chromosomes, with both significantly different methylation density and methylation ratio. Baseline methylation density and methylation ratio of chromosome 6 [32400000-32599999] were both high in exemestane resistance. High baseline methylation ratios of chromosome 3 [67800000-67999999] (P = .013), chromosome 3 [140200000-140399999] (P = .037), and chromosome 12 [101200000-101399999] (P = .026) could also predict exemestane resistance. During exemestane treatment, synchronized changes in methylation density and methylation ratio in chromosome 6 [32400000-32599999] could accurately stratify patients in terms of progression-free survival (P = .000033). Cutoff values of methylation density and methylation ratio for chromosome 6 [149600000-149799999] were 0.066 and 0.076, respectively. CONCLUSION: Methylation change in chromosome 6 [149600000-149799999] is an ideal predictor of exemestane resistance with great clinical potential.

HER2-specific T lymphocytes kill both trastuzumab-resistant and trastuzumab-sensitive breast cell lines in vitro.

OBJECTIVE: Although the development of trastuzumab has improved the outlook for women with human epidermal growth factor receptor 2 (HER2)-positive breast cancer, the resistance to anti-HER2 therapy is a growing clinical dilemma. We aim to determine whether HER2-specific T cells generated from dendritic cells (DCs) modified with HER2 gene could effectively kill the HER2-positive breast cancer cells, especially the trastuzumab-resistant cells. METHODS: The peripheral blood mononuclear cells (PBMCs) from healthy donors, whose HLA haplotypes were compatible with the tumor cell lines, were transfected with reconstructive human adeno-association virus (rhAAV/HER2) to obtain the specific killing activities of T cells, and were evaluated by lactate dehydrogenase (LDH) releasing assay. RESULTS: Trastuzumab produced a significant inhibiting effect on SK-BR-3, the IC50 was 100ng/ml. MDA-MB-453 was resistant to trastuzumab even at a concentration of 10,000 ng/ml in vitro. HER2-specific T lymphocytes killed effectively SK-BR-3 [(69.86±13.41)%] and MDA-MB-453 [(78.36±10.68)%] at 40:1 (effector:target ratio, E:T), but had no significant cytotoxicity against HER2-negative breast cancer cell lines MDA-MB-231 or MCF-7 (less than 10%). CONCLUSION: The study showed that HER2-specific T lymphocytes generated from DCs modified by rhAAV/HER2 could kill HER2-positive breast cancer cell lines in a HER2-dependent manner, and result in significantly high inhibition rates on the intrinsic trastuzumab-resistant cell line MDA-MB-453 and the tastuzumab-sensitive cell line SK-BR-3. These results imply that this immunotherapy might be a potential treatment to HER2-positive breast cancer.

[Prognostic value of cyclin E and its relation to blood vessel invasion in rectal cancer].

OBJECTIVE: To investigate the expression of cyclin E in rectal carcinoma and its prognostic significance. METHODS: Cyclin E expression was examined by Western blotting in tumor tissue samples from 130 potentially resected rectal cancer patients with pathological stages I- III. Blood vessel invasion (BVI) was detected by immunohistochemistry. Multivariate analysis using the COX proportional hazards models was applied to evaluate the independent prognostic tumor markers of rectal cancer. RESULTS: The high expression rate of cyclin E in rectal carcinoma tissue was 23.1%(30/130). Except for a positive correlation with BVI and the gross configuration of tumor, the expression of cyclin E showed no significant relation to other clinicopathological factors. The 5-year disease-specific survival rate of cyclin E high expression group was 29.2%, which was significantly lower as compared to that of cyclin low expression group 70.5% (P<0.05). Multivariate analysis revealed that histology and cyclin E expression were independent prognostic indicators for rectal cancer patients at stages I- III. Compared to those with low expression levels, patients with high cyclin E levels had the hazard ratio (95%CI) for death from rectal cancer for 3.544 (1.528-8.215). In stage I- II, multivariate analysis showed that stronger predictive values of cyclin E expression even were detected. Patients with low cyclin E expression and negative BVI had a significantly better prognosis than those with high cyclin E expression and positive BVI. CONCLUSIONS: The expression of cyclin E is independent prognostic factor in rectal carcinoma at stages I- III. Detecting the expression of cyclin E and/or combined with BVI may help to predict clinical outcome and design further individualized intensive adjuvant treatment.