Targeting hormone-resistant breast cancer cells with docetaxel: a look inside the resistance

Aim: The study aims to analyze the effect of long-term incubation of ERα-positive MCF7 breast cancer cells with 4-hydroxytamoxifen (HT) on their sensitivity to tubulin polymerization inhibitor docetaxel. Methods: The analysis of cell viability was performed by the MTT method. The expression of signaling proteins was analyzed by immunoblotting and flow cytometry. ERα activity was evaluated by gene reporter assay. To establish hormone-resistant subline MCF7, breast cancer cells were treated with 4-hydroxytamoxifen for 12 months. Results: The developed MCF7/HT subline has lost sensitivity to 4-hydroxytamoxifen, and the resistance index was 2. Increased Akt activity (2.2-fold) and decreased ERα expression (1.5-fold) were revealed in MCF7/HT cells. The activity of the estrogen receptor α was reduced (1.5-fold) in MCF7/HT. Evaluation of class III β-tubulin expression (TUBB3), a marker associated with metastasis, revealed the following trends: higher expression of TUBB3 was detected in triple-negative breast cancer MDA-MB-231 cells compared to hormone-responsive MCF7 cells (P < 0.05). The lowest expression of TUBB3 was found in hormone-resistant MCF7/HT cells (MCF7/HT < MCF7 < MDA-MB-231, approximately 1:2:4). High TUBB3 expression strongly correlated with docetaxel resistance: IC₅₀ value of docetaxel for MDA-MB-231 cells was greater than that for MCF7 cells, whereas resistant MCF7/HT cells were the most sensitive to the drug. The accumulation of cleaved PARP (a 1.6-fold increase) and Bcl-2 downregulation (1.8-fold) were more pronounced in docetaxel-treated resistant cells (P < 0.05). The expression of cyclin D1 decreased (2.8-fold) only in resistant cells after 4 nM docetaxel treatment, while this marker was unchanged in parental MCF7 breast cancer cells. Conclusion: Further development of taxane-based chemotherapy for hormone-resistant cancer looks highly promising, especially for cancers with low TUBB3 expression.

Association of high TUBB3 with resistance to adjuvant docetaxel-based chemotherapy in gastric cancer: translational study of ITACA-S

BACKGROUND

No predictive markers for chemotherapy activity have been validated in gastric cancer (GC). The potential value of class III β-tubulin (TUBB3) as biomarker for prognosis and resistance to taxane-based therapy was reported.

METHODS

We analyzed GC samples of patients enrolled in the Intergroup Trial of Adjuvant Chemotherapy in Adenocarcinoma of the Stomach (ITACA-S), a randomized adjuvant study comparing 5-fluorouracil/leucovorin (5-FU/LV) and docetaxel-based sequential chemotherapy. TUBB3 was quantitated by selected reaction monitoring mass spectrometry and patients were stratified using a threshold of 750 attomoles per microgram (amol/µg). Cox proportional modeling and Kaplan-Meier survival analysis were used to assess the impact of TUBB3 expression on overall survival (OS) and disease-free survival.

RESULTS

Patients with TUBB3 protein levels >750 and <750 amol/µg were 21.9% and 78.1%, respectively, and were well-balanced between treatment arms. TUBB3 protein levels were not prognostic. Whereas no survival differences according to the 2 arms were observed in the subgroup with low TUBB3 expression (5-year OS 47% vs 40%; p = 0.44), patients with high TUBB3 had a clinically meaningful poorer OS when receiving docetaxel-based versus 5-FU/LV chemotherapy (5-year OS 31% vs 54%; p = 0.09), with a statistically significant interaction between TUBB3 and treatment (p = 0.049).

CONCLUSIONS

The quantification of TUBB3 might be considered as a negative predictive biomarker of benefit from taxane-based therapy in GC. Studies are needed to evaluate its role in the neoadjuvant setting.

Four-weekly Low-dose Gemcitabine and Paclitaxel in Patients With Platinum-resistant Urothelial Cancer and Performance Status 2/3

BACKGROUND/AIM

Immune check-point inhibitors are often unsuitable for patients with urothelial cancer with a poor performance status (PS 2 or 3). The aim of this study was to assess the safety and usefulness of combined therapy with low-dose gemcitabine and paclitaxel every 4 weeks.

PATIENTS AND METHODS

Thirty patients were treated with gemcitabine (700 mg/m² on day 1) and paclitaxel (70 mg/m² on day 1) every 4 weeks. The predictive value of human antigen-R (HuR) and class III β-tubulin (TUBB3) were also analyzed.

RESULTS

There was no severe adverse event nor significant decrease in quality of life. The survival period of patients treated with this regimen was significantly longer than that of those treated with best supportive care. The expression pattern of HuR negativity and TUBB3 positivity predicted significantly worse overall survival.

CONCLUSION

Our regimen was suitable as second-line therapy for patients with advanced platinum-resistant UC with a poor PS. However, a HuR-negative and TUBB3-positive expression pattern appears to confer poorer outcome.

The relationship between the expression of thymidylate synthase, dihydropyrimidine dehydrogenase, orotate phosphoribosyltransferase, excision repair cross-complementation group 1 and class III β-tubulin, and the therapeutic effect of S-1 or carboplatin plus paclitaxel in non-small-cell lung cancer

Previous studies have reported that the expressions of specific proteins may predict the efficacy of chemotherapy agents for non-small cell lung cancer (NSCLC) patients. The present study evaluated the expression of proteins hypothesized to be associated with the effect of chemotherapeutic agents in 38 NSCLC patients with pathological stage II and IIIA. The subjects received carboplatin plus paclitaxel (CP) or S-1 as adjuvant chemotherapy following complete resection. The protein expressions evaluated were those of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phsphoribosyltransferase (OPRT), which were suspected to be associated with the effect of S-1 agents, excision repair cross-complementation group 1 (ERCC1), which was suspected to be associated with the effect of platinum-based agents, and class III β-tubulin (TUBB3), which was suspected to be associated with the effect of taxane-based agents. The positive rate of TS was 55.3% (n=21/38), DPD was 57.9% (n=22/38), OPRT was 42.1% (n=16/38), ERCC1 was 47.4% (n=18/38) and TUBB3 was 44.7% (n=17/38). Among the patients who received S-1 adjuvant chemotherapy, TS-negative cases demonstrated a significantly better disease-free survival than positive cases. Thus, TS protein expression may have been a factor that predicted the effect of S-1 agent as adjuvant chemotherapy.

Prognostic effect of class III β-tubulin and Topoisomerase-II in patients with advanced thymic carcinoma who received combination chemotherapy, including taxanes or topoisomerase-II inhibitors

Class III β-tubulin (TUBB3) and Topoisomerase-II (topo-II) are considered to be the predictors of therapeutic efficacy and outcome in several types of human neoplasm. However, whether TUBB3 or topo-II may predict the response to combination chemotherapy and prognosis in patients with advanced thymic carcinoma (ATC) remains unclear. The aim of the present study was to investigate the prognostic significance of TUBB3 and topo-II expression levels in ATC. A total of 34 patients with ATC who received combination chemotherapy were enrolled in the present study. Immunohistochemical analysis was used to examine the expression of TUBB3, topo-II and Ki-67 in tumor specimens obtained by surgical resection or biopsy. TUBB3 and topo-II were highly expressed in 38 and 53% of the tumors, respectively. Progression-free survival (PFS) was significantly shorter in patients with high levels of TUBB3 compared with those with low levels of TUBB3 (P<0.01), whereas no significant difference in PFS between patients with high and low topo-II expression levels was observed (P=0.31). Patients with overexpression of TUBB3 or topo-II exhibited significantly shorter overall survival rates (OS) compared with those patients with low levels of expression of these proteins (TUBB3; P=0.01, topo-II; P=0.01). Multivariate analysis demonstrated that a high level of TUBB3 expression was an independent unfavorable prognostic factor for OS, and a high level of topo-II expression tended to correlate with poor prognosis without statistical significance. Additionally, a subset analysis demonstrated that the treatment with taxanes, but not topo-II inhibitors, tended to prolong OS in patients with TUBB3 overexpression and there was significant survival advantage of chemoradiotherapy over chemotherapy in patients with topo-II overexpression. It was revealed that an enhanced expression of TUBB3 or topo-II was clearly associated with clinical outcomes in patients with ATC who received combination chemotherapy, including taxanes or topo-II inhibitors, suggesting the prognostic significance of these markers.

Expression of excision repair cross-complementation group 1 and class III β-tubulin in thymic carcinoma

Thymic carcinoma is a rare mediastinum malignant tumor derived from thymic epithelial cells. With the exception of complete resection, an effective therapy has not been established to date for advanced or relapsed thymic carcinoma. The present study examined the protein expression of excision repair cross-complementation group 1 (ERCC1) and class III β-tubulin (TUBB3), which are consider to be indicators of the anticancer activity of platinum-based and taxane-based chemotherapy, respectively. The expression of ERCC1 and TUBB3 proteins was examined in 40 thymic carcinoma patients who underwent either surgical resection or core-needle biopsy. The present study investigated whether the expression of ERCC1 and TUBB3 proteins was associated with the overall survival and clinicopathological factors of thymic carcinoma patients. The expression of ERCC1 and TUBB3 proteins was also evaluated in 50 patients who underwent curative resection for non-small cell lung cancer (NSCLC). The expression of ERCC1 and TUBB3 proteins was positive in 8 cases (20%) among the thymic carcinoma patients. ERCC1 was expressed in 21 cases (42%), while TUBB3 was expressed in 27 cases (54%), among the 50 NSCLC patients evaluated in the present study. Only complete resection was observed to be associated with a better prognosis than incomplete resection (P=0.0341). Other clinicopathological factors, including expression of ERCC1 and TUBB3 proteins, exhibited no effect on overall survival. The expression of ERCC1 and TUBB3 proteins in the thymic carcinoma cases was lower than that in the NSCLC cases. The present results suggest a possibility for better antitumor effects of platinum-based and taxane-based chemotherapy on thymic carcinoma patients.

Organ of Corti explants direct tonotopically graded morphology of spiral ganglion neurons in vitro

The spiral ganglion is a compelling model system to examine how morphological form contributes to sensory function. While the ganglion is composed mainly of a single class of type I neurons that make simple one-to-one connections with inner hair cell sensory receptors, it has an elaborate overall morphological design. Specific features, such as soma size and axon outgrowth, are graded along the spiral contour of the cochlea. To begin to understand the interplay between different regulators of neuronal morphology, we cocultured neuron explants with peripheral target tissues removed from distinct cochlear locations. Interestingly, these "hair cell microisolates" were capable of both increasing and decreasing neuronal somata size, without adversely affecting survival. Moreover, axon characteristics elaborated de novo by the primary afferents in culture were systematically regulated by the sensory endorgan. Apparent peripheral nervous system (PNS)-like and central nervous system (CNS)-like axonal profiles were established in our cocultures allowing an analysis of putative PNS/CNS axon length ratios. As predicted from the in vivo organization, PNS-like axon bundles elaborated by apical cocultures were longer than their basal counterparts and this phenotype was methodically altered when neuron explants were cocultured with microisolates from disparate cochlear regions. Thus, location-dependent signals within the organ of Corti may set the "address" of neurons within the spiral ganglion, allowing them to elaborate the appropriate tonotopically associated morphological features in order to carry out their signaling function. J. Comp. Neurol. 524:2182-2207, 2016. © 2015 Wiley Periodicals, Inc.

High levels of class III β-tubulin expression are associated with aggressive tumor features in breast cancer

Overexpression of class III β-tubulin (TUBB3), a factor that confers dynamic properties to microtubules, is a candidate biomarker for resistance to microtubule-targeting chemotherapeutics in breast and other types of solid cancer. Discrepant results from previous studies, with respect to the association of TUBB3 expression levels with breast cancer phenotype and patient prognosis, prompted the present study to investigate TUBB3 expression in a large cohort of breast cancer cases, with available clinical follow-up data. A preexisting breast cancer prognosis tissue microarray, containing a single 0.6 mm tissue core from each of 2,197 individual patients with breast cancer, was analyzed for TUBB3 expression by immunohistochemistry. The results of the present study revealed that TUBB3 expression was less frequent in lobular breast cancer cases (34%), compared with that of cancer cases of alternative histologies, including breast cancer of no special type (60%; P<0.0001). High TUBB3 positivity was associated with high tumor grade (P<0.0001), negativity for estrogen (P<0.0001) and progesterone receptors (P<0.004), as well as the presence of human epidermal growth factor 2 amplification (P<0.0001) and a triple-negative phenotype (P<0.0001). TUBB3 overexpression was additionally associated with reduced patient survival if all breast cancer cases of any histology were jointly analyzed (P=0.0088); however this link was not evident in the subset of breast cancer cases of no special type, or in a multivariate analysis including the established prognostic factors of tumor stage, grade and nodal stage. In conclusion, the present study demonstrated that TUBB3 overexpression was associated with adverse features of breast cancer, and that TUBB3 may possess a distinct role in lobular breast cancer cases, compared with alternative histological subtypes. The results of the present study do not support a clinically relevant role for TUBB3 as a prognostic marker in breast cancer.

Analysis of ERCC1, BRCA1, RRM1 and TUBB3 as predictors of prognosis in patients with non-small cell lung cancer who received cisplatin-based adjuvant chemotherapy: A prospective study

Although adjuvant platinum-based chemotherapy has been demonstrated to improve survival in patients with completely resected non-small cell lung cancer (NSCLC), individualized approaches to therapy are urgently required to improve the treatment efficacy and reduce unnecessary toxicity. It was hypothesized in the present study that the protein levels of excision repair cross-complementation group 1 (ERCC1), breast cancer 1 (BRCA1), ribonucleotide reductase M1 (RRM1) and class III β-tubulin (TUBB3) may influence the therapeutic effect of adjuvant cisplatin-based chemotherapy. The expression of ERCC1, BRCA1, RRM1 and TUBB3 in tissues obtained from 84 patients with NSCLC was analyzed in the present non-interventional study by immunohistochemistry prior to adjuvant chemotherapy. All patients received adjuvant cisplatin-based chemotherapy. The primary endpoint in the present study was disease free survival (DFS). Out of the 84 tumors, the expression of ERCC1, BRCA1, RRM1 and TUBB3 was identified in 46 (55%), 11 (13%), 73 (87%) and 76 (90%) tissues, respectively. A beneficial response to adjuvant cisplatin-based chemotherapy in DFS was associated with the absence of the expression of ERCC1 [hazard ratio (HR), 2.166; 95% confidence interval (CI), 1.049-4.474; P=0.037] and BRCA1 (HR, 2.419; 95% CI, 1.127-5.193; P=0.023), but not with the expression status of RRM1 (HR, 0.568; 95% CI, 0.234-1.379; P=0.212) or TUBB3 (HR, 1.874; 95% CI, 0.448-7.842; P=0.39). In addition, patients lacking the expression of ERCC1 and BRCA1 benefited more from adjuvant cisplatin-based chemotherapy compared with patients that expressed either ERCC1 or BRCA1 (HR, 3.102; 95% CI, 1.343-7.163; P=0.008). The expression of ERCC1 and BRCA1 was significantly associated with the DFS time in patients with NSCLC treated with adjuvant cisplatin-based chemotherapy, respectively. The combination of the ERCC1 and BRCA1 expression levels may be a promising prognostic prediction for adjuvant cisplatin-based chemotherapy.

Prognostic significance of the mRNA expression of ERCC1, RRM1, TUBB3 and TYMS genes in patients with non-small cell lung cancer

The present study aimed to investigate the prognostic value of excision repair cross-complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), class III β-tubulin (TUBB3) and thymidylate synthase (TYMS) in patients with non-small cell lung cancer (NSCLC) receiving platinum-based adjuvant chemotherapy. The mRNA expression of these genes was assessed in 72 tumor tissue samples obtained following surgery, using multiplex branched-DNA technology. Subsequent to surgery, all 72 patients with NSCLC were treated with platinum-based chemotherapy. The expression of these five genes was analyzed and the correlation with clinical characteristics and patient survival was investigated. Among the 72 samples, the incidence rate of mRNA expression of ERCC1 was 38.9% (28/72), RRM1 was 55.6% (40/72), TUBB3 was 47.2% (34/72) and TYMS was 62.5% (45/72). The incidence rate of ERCC1 expression in adenocarcinoma (34.2%) was significantly lower than that in non-adenocarcinoma (44.1%; P<0.05). Furthermore, the incidence rates of TYMS and TUBB3 expression in the high-median differentiation tissue samples were significantly lower than those in the low differentiation tissue samples (P<0.05). When the correlation of gene expression and patient survival was analyzed, high expression of ERCC1, RRM1, TUBB3 or TYMS was found to be associated with poor prognosis (P<0.001, P=0.001, P=0.001 and P=0.001, respectively). ERCC1, RRM1, TUBB3 and TYMS are key factors involved in survival following surgical treatment in patients with NSCLC. The mRNA expression of these genes may have prognostic value for patients with NSCLC treated with platinum-based chemotherapy.

Immunohistochemistry evaluation of biomarker expression in non-small cell lung cancer (Pharmacogenoscan study)

OBJECTIVES

Platinum-based chemotherapy regimens are the standard treatment of non-small cell lung cancer (NSCLC). In this study, our objective was to identify tumor tissue protein biomarkers that might predict a benefit from these treatments.

MATERIALS AND METHODS

The Pharmacogenoscan study prospectively included consecutive chemotherapy-naive NSCLC patients at any stage between 2005 and 2010 at six hospitals in the Rhône-Alpes-Auvergne region of France. Of the 537 patients in the full analysis set, 460 had a complete histological diagnosis. We used the tumor tissue samples for an immunohistochemical evaluation of eight biomarkers: ERCC1, BRCA1, p53, p27kip1, class III β-tubulin (TUBB3), Bax, Fas, and FasL. We looked for associations between these biomarkers and the disease control rate (DCR) after 2/3 cycles of platinum-based chemotherapy, progression-free survival (PFS), and overall survival (OS).

RESULTS

A tissue sample adequate for testing at least one biomarker was available for 289 patients. We found no significant association between biomarker expression levels and clinical or pathological variables; TUBB3 showed a trend toward higher expression in adenocarcinomas (P=0.005). For none of the biomarkers were significant associations found between expression level and DCR, PFS, or OS. TUBB3-negative and FasL-negative tumors showed associations of borderline significance with higher DCR.

CONCLUSION

In a large cohort of patients with predominantly advanced or metastatic NSCLC, none of eight tested immunohistochemical biomarkers predicted the chemotherapy response or survival. Our data indicate limited usefulness of protein biomarkers in metastatic NSCLC and a need for further research based on molecular signatures of greater complexity.

High expression of class III β-tubulin in small cell lung carcinoma

Class III β-tubulin (TUBB3) is emerging as a biomarker in a number of cancers. TUBB3 has been shown to be a prognostic indicator of more aggressive disease and a predictor of resistance to taxanes and vinca alkaloids. To date, there is little data on TUBB3 expression in small cell lung carcinoma (SCLC). The primary objective of this study was to determine the expression of TUBB3 in SCLC. Immunohistochemical staining of SCLC tumor specimens was performed using standard procedures. Expression of TUBB3 was determined as a composite of the percentage of malignant cells staining positive and the intensity of staining. Clinical and tumor data for each patient was compared with the degree of TUBB3 expression. A total of 66 SCLCs were evaluable for TUBB3 expression. The majority of specimens (n=56, 85%) had high expression of TUBB3. Only 4.5% (n=3) had low expression of TUBB3. The mean distribution of positive staining for the specimens was 87.3±1.8% (mean ± SE). Specimens from core biopsies were significantly more likely to have high TUBB3 expression when compared with fine needle aspirates (P=0.004). There were no other significant findings when comparing clinical or tumor characteristics. Overall, we found that expression of TUBB3 in SCLC is higher than expected. Innate resistance to microtubule inhibitors, such as the taxanes and vinca alkaloids, may be associated with this finding. Attempts at microtubule inhibition with novel agents may be able to overcome this resistance mechanism. Further evaluation of TUBB3 as a biomarker in SCLC is warranted.

Class III β-tubulin overexpression in ovarian clear cell and serous carcinoma as a maker for poor overall survival after platinum/taxane chemotherapy and sensitivity to patupilone

OBJECTIVE

Clear cell carcinoma of the ovary is a distinct subtype of epithelial cancer associated with chemoresistance and poor outcome compared with serous papillary carcinomas. Resistance to paclitaxel has been linked to serous papillary overexpression of class III β-tubulin in several human cancers but inadequately characterized among clear cell carcinoma of the ovary. Chemoresistance has also been variably linked to the drug efflux pump p-glycoprotein. Epothilones are microtubule-stabilizing agents with putative activity in paclitaxel-resistant malignancies. In this study, we clarify the relationship between class III β-tubulin and p-glycoprotein expression in clear cell carcinoma of the ovary, clinical outcome, and in vitro responsiveness to patupilone and paclitaxel.

STUDY DESIGN

Class III β-tubulin and p-glycoprotein were quantified by real time polymerase chain reaction in 61 fresh-frozen tissue samples and 11 cell lines. Expression by polymerase chain reaction was correlated with immunohistochemistry and overall survival. IC50 was determined using viability/metabolic assays. Impact of class III β-tubulin down-regulation on IC50 was assessed with small interfering RNAs.

RESULTS

Clear cell carcinoma of the ovary overexpressed class III β-tubulin and p-glycoprotein relative to serous papillary carcinomas carcinomas in fresh-frozen tissues and cell lines. Class III β-tubulin immunohistochemistry reflected real time polymerase chain reaction results and overexpression stratified patients by overall survival. P-glycoprotein correlated with in vitro paclitaxel resistance, but not clinical outcome. Clear cell carcinoma of the ovary were exquisitely sensitive to patupilone in a manner that correlated with class III β-tubulin expression.

CONCLUSION

Class III β-tubulin overexpression in clear cell carcinoma of the ovary discriminates poor prognosis, serves as a marker for sensitivity to patupilone, and may contribute to paclitaxel resistance. Immunohistochemistry reliably identifies tumors with overexpression of class III β-tubulin, and accordingly a subset of individuals likely to respond to patupilone.

High expression levels of class III β-tubulin in resected non-small cell lung cancer patients are predictive of improved patient survival after vinorelbine-based adjuvant chemotherapy

The aim of the present study was to determine the frequency and predictive value of the expression of tumor microtubule components in patients with resected non-small cell lung cancer (R-NSCLC) subsequently treated with vinorelbine-based adjuvant chemotherapy. The expression of the microtubule components was evaluated in 85 R-NSCLC tumor samples using immunohistochemistry. All patients received vinorelbine-based chemotherapy. The predictive value of microtubule protein expression for disease-free survival (DFS) and overall survival (OS) was assessed. The expression of the microtubule components was not associated with any baseline clinicopathological factors in the R-NSCLC patients. High tumor expression levels of class III β-tubulin were correlated with an improved DFS (P=0.033) and a trend towards a longer OS (P=0.226). Class II and IV β-tubulins were not correlated with patient outcome. Multivariate analysis of factors, including gender, age, histology, stage and class II, III and IV β-tubulin expression demonstrated that high levels of class III β-tubulin expression were correlated independently with DFS (P= 0.031). These findings suggest that high class III β-tubulin expression levels in resected tumors are predictive of improved DFS in R-NSCLC patients receiving vinorelbine-based chemotherapy.