Taxol: a new agent active in melanoma and ovarian cancer

Identification of lncRNA Signature Associated With Pan-Cancer Prognosis

Long noncoding RNAs (lncRNAs) have emerged as potential prognostic markers in various human cancers as they participate in many malignant behaviors. However, the value of lncRNAs as prognostic markers among diverse human cancers is still under investigation, and a systematic signature based on these transcripts that related to pan-cancer prognosis has yet to be reported. In this study, we proposed a framework to incorporate statistical power, biological rationale, and machine learning models for pan-cancer prognosis analysis. The framework identified a 5-lncRNA signature (ENSG00000206567, PCAT29, ENSG00000257989, LOC388282, and LINC00339) from TCGA training studies (n = 1,878). The identified lncRNAs are significantly associated (all P ≤ 1.48E-11) with overall survival (OS) of the TCGA cohort (n = 4,231). The signature stratified the cohort into low- and high-risk groups with significantly distinct survival outcomes (median OS of 9.84 years versus 4.37 years, log-rank P = 1.48E-38) and achieved a time-dependent ROC/AUC of 0.66 at 5 years. After routine clinical factors involved, the signature demonstrated better performance for long-term prognostic estimation (AUC of 0.72). Moreover, the signature was further evaluated on two independent external cohorts (TARGET, n = 1,122; CPTAC, n = 391; National Cancer Institute) which yielded similar prognostic values (AUC of 0.60 and 0.75; log-rank P = 8.6E-09 and P = 2.7E-06). An indexing system was developed to map the 5-lncRNA signature to prognoses of pan-cancer patients. In silico functional analysis indicated that the lncRNAs are associated with common biological processes driving human cancers. The five lncRNAs, especially ENSG00000206567, ENSG00000257989 and LOC388282 that never reported before, may serve as viable molecular targets common among diverse cancers.

Urokinase exerts antimetastatic effects by dissociating clusters of circulating tumor cells

Clusters of circulating tumor cells (CTC) exhibit more robust metastatic properties than single CTC. Thus, understanding the distinct behaviors of CTC clusters and how CTC clustering is regulated may offer new insights into how to limit metastasis. In this study, we utilized an in vivo confocal system to observe the clustering behavior of CTC in real time, finding that the number of clusters increased proportionally with the growth of the primary tumor. Our experiments also indicated that the flow rate of the CTC clusters in blood vessels was relatively slower than single CTC due to increased vessel wall adhesion. Depending on disease stage, 5% to 10% of total CTC in circulation were in clusters, with this proportion increasing to >24% within lung metastases examined. Notably, in the 4T1 mouse model of breast cancer metastasis, we found that injecting host animals with urokinase-type plasminogen activator, a clinical thrombolytic agent, was effective at preventing the assembly of CTC clusters and prolonging overall host survival by approximately 20% relative to control animals. Our results suggest a tractable approach to limit metastasis by suppressing the formation or stability of CTC clusters circulating in the blood of cancer patients.

Role of tumor necrosis factor alpha-induced protein 1 in paclitaxel resistance

Paclitaxel has been extensively used as an antitumor drug to treat a broad range of epithelial cancers, including breast and cervical cancers. However, the efficacy of this drug is greatly limited by the development of acquired resistance. Identification of the underlying resistance mechanisms may inform the development of new therapies that elicit long-term response of tumors to paclitaxel treatment. Here we report that increased expression of TNFAIP1 (tumor necrosis factor alpha-induced protein 1) confers acquired resistance to paclitaxel. TNFAIP1 is shown to compete with paclitaxel for binding to β-tubulin, thereby preventing paclitaxel-induced tubulin polymerization, cell cycle arrest and ultimate cell death. We also show that expression of TNFAIP1 is regulated by the transcriptional factor Sp1. In a xenograft mouse model, increased expression of TNFAIP1 decreases, whereas knockdown of TNFAIP1 increases tumor response to paclitaxel. Therefore, these results reveal tnfaip1 as a novel paclitaxel-resistance associated gene and suggest that TNFAIP1 may represent a valuable therapeutic target for the treatment of cancer.

Effectiveness of carboplatin and paclitaxel as first- and second-line treatment in 61 patients with metastatic melanoma

Background

Patients with metastatic melanoma have a very unfavorable prognosis with few therapeutic options. Based on previous promising experiences within a clinical trial involving carboplatin and paclitaxel a series of advanced metastatic melanoma patients were treated with this combination.

Methods

Data of all patients with cutaneous metastatic melanoma treated with carboplatin and paclitaxel (CP) at our institution between October 2005 and December 2007 were retrospectively evaluated. For all patients a once-every-3-weeks dose-intensified regimen was used. Overall and progression free survival were calculated using the method of Kaplan and Meier. Tumour response was evaluated according to RECIST criteria.

Results

61 patients with cutaneous metastatic melanoma were treated with CP. 20 patients (85% M1c) received CP as first-line treatment, 41 patients (90.2% M1c) had received at least one prior systemic therapy for metastatic disease. Main toxicities were myelosuppression, fatigue and peripheral neuropathy. Partial responses were noted in 4.9% of patients, stable disease in 23% of patients. No complete response was observed. Median progression free survival was 10 weeks. Median overall survival was 31 weeks. Response, progression-free and overall survival were equivalent in first- and second-line patients. 60 patients of 61 died after a median follow up of 7 months. Median overall survival differed for patients with controlled disease (PR+SD) (49 weeks) compared to patients with progressive disease (18 weeks).

Conclusions

Among patients with metastatic melanoma a subgroup achieved disease control under CP therapy which may be associated with a survival benefit. This potential advantage has to be weighed against considerable toxicity. Since response rates and survival were not improved in previously untreated patients compared to pretreated patients, CP should thus not be applied as first-line treatment.

Increased nuclear localization of transcription factor Y-box binding protein 1 accompanied by up-regulation of P-glycoprotein in breast cancer pretreated with paclitaxel

PURPOSE

The Y-box binding protein 1 (YB-1) regulates expression of P-glycoprotein encoded by the MDR1 gene. There have been no previous studies regarding the involvement of YB-1 in the development of resistance to paclitaxel. The present study was done to examine how paclitaxel affects the localization and expression of YB-1 in breast cancer.

EXPERIMENTAL DESIGN

We evaluated the expression and localization of YB-1 and P-glycoprotein in breast cancer tissues obtained from 27 patients before and after treatment with paclitaxel. The effect of paclitaxel on localization of cellular YB-1 was examined by using GFP-YB-1. Interaction of YB-1 with the Y-box motif of the MDR1 promoters was studied by electrophoretic mobility shift assay. The effects of paclitaxel on MDR1 promoter activity were examined by luciferase assay.

RESULTS

Of 27 breast cancer tissues treated with paclitaxel, nine (33%) showed translocation of YB-1 from the cytoplasm to the nucleus together with increased expression of P-glycoprotein during the course of treatment. Twelve breast cancer tissues (44%) showed neither translocation of YB-1 nor increased expression of P-glycoprotein. Nuclear translocation of YB-1 was correlated significantly with increased expression of P-glycoprotein (P=0.0037). Confocal analysis indicated that paclitaxel induced nuclear translocation of green fluorescent fused YB-1 in MCF7 cells. Furthermore, binding of YB-1 to the Y-box of MDR1 promoter was increased in response to treatment with paclitaxel. In addition, MDR1 promoter activity was significantly up-regulated by paclitaxel in MCF7 cells (P<0.001).

CONCLUSIONS

The results of the present study suggested that YB-1 may be involved in the development of resistance to paclitaxel in breast cancer.

Phase I study of temozolomide plus paclitaxel in patients with advanced malignant melanoma and associated in vitro investigations

The purpose of this study was to determine activity of temozolomide combined with paclitaxel or epothilone B in vitro, and to investigate the combination of temozolomide with paclitaxel in a Phase I clinical trial. Melanoma cell lines A375P and DX3 were treated with temozolomide and either paclitaxel or epothilone B. Combination indices were determined to assess the degree of synergism. In a clinical study, 21 patients with malignant melanoma were treated with increasing doses of temozolomide (orally, days 1–5), in combination with a fixed dose of paclitaxel (i.v. infusion day 1), followed by dose escalation of the latter drug. Cycles of treatment were repeated every 3 weeks. Pharmacokinetics of both agents were determined on day 1, with temozolomide pharmacokinetics also assessed on day 5. All three compounds were active against the melanoma cell lines, with epothilone B being the most potent. There was a strong degree of synergism between temozolomide and either paclitaxel or epothilone B. In the clinical study, no pharmacokinetic interaction was observed between temozolomide and paclitaxel. Dose escalation of both drugs to clinically active doses was possible, with no dose-limiting toxicities observed at 200 mg m⁻² day⁻¹ temozolomide and 225 mg m⁻² day⁻¹ paclitaxel. There were two partial responses out of 15 evaluable patients. One patient remains alive and symptom-free at 4 years after treatment. Temozolomide and paclitaxel may be administered safely at clinically effective doses. Further evaluation of these combinations in melanoma is warranted.

Mutation of the class I beta-tubulin gene does not predict response to paclitaxel for breast cancer

Mutation of the class I beta-tubulin gene has been reported to be one of the mechanisms that cause resistance to paclitaxel. To assess the relationship between paclitaxel-resistance and class I beta-tubulin gene mutation in breast cancer, Japanese patients with breast cancer were screened for the class I beta-tubulin gene mutation. Total RNA was isolated from 82 breast cancer specimens and the corresponding normal tissues. Twenty-four of the 82 patients were treated with paclitaxel preoperatively and 12 of them did not respond to the treatment. Of the 82 breast cancer patients, 15 (18.3%) had silent polymorphism in exon 4, Leu217Leu (CTG/CTA). However, no mutations showing amino acid substitution of the beta-tubulin gene were detected in any of the patients, including 12 patients who did not respond to paclitaxel. Class I beta-tubulin gene mutation with amino acid substitution was not detected in 82 breast cancer specimens. Our results suggest that mutation of the class I beta-tubulin gene is unlikely to play an important role in the mechanism of resistance to paclitaxel in breast cancer.

Paclitaxel (Taxol) treatment for refractory ovarian cancer: phase II clinical trial

OBJECTIVE

Our aim was to determine the efficacy and toxicity of paclitaxel in the treatment of refractory and platinum-resistant epithelial ovarian cancer.

STUDY DESIGN

Eligibility required three prior failed chemotherapy regimens and documented platinum resistance. One hundred patients with advanced ovarian cancer received paclitaxel 135 mg/m2 over 24 hours every 21 days with optional granulocyte colony-stimulating factor support.

RESULTS

Paclitaxel was generally well tolerated. In four patients bowel perforation or fistula developed. After three cycles 34% of patients had stable disease and 25% of patients demonstrated a response, either partial or complete. After six cycles 24% of patients continued to respond. To date, six patients have achieved a complete response.

CONCLUSION

A 25% response rate in patients with refractory ovarian cancer was observed, which was durable to six cycles.

Preclinical activity of taxotere (RP 56976, NSC 628503) against freshly explanted clonogenic human tumour cells: comparison with taxol and conventional antineoplastic agents

Taxotere (TER) and taxol (TA) are new antitumour agents currently undergoing clinical evaluation. We studied the antineoplastic effects of these agents (final concentrations: 4.0, 0.4, 0.04 mumol/l) on the in vitro proliferation of clonogenic cells from freshly explanted human tumours using a capillary soft agar cloning system. We also compared the activity of these new compounds to conventional antineoplastic agents (bleomycin, cisplatin, dacarbazine, doxorubicin, etoposide, 5-fluorouracil, vinblastine, interferon-alpha 2). Using a 21-28-day continuous drug exposure, 54/81 specimens (67%) were evaluable for comparisons, and using a 1-h drug exposure followed by 21-28 days incubation, 50/80 specimens (63%) were similarly evaluable. With both schedules, TA and TER showed concentration-related antitumour activity. At 0.4 mumol/l, median colony survival was 0.61 x control (range 0.09-0.96) for TA and 0.51 x control (0.15-0.81) for TER in the 1-h incubation (P = 0.0002). Median colony formation was also reduced significantly more by TER as compared to TA in the long-term incubation schedule. Statistical analysis indicated that TER but not TA was significantly more active than cisplatin (P = 0.02), doxorubicin (P = 0.01), 5-fluorouracil (P = 0.01) and interferon-alpha 2 (P = 0.01). We conclude that TER and TA are more active against in vitro tumour colony formation from freshly explanted human tumours. TER appears to be slightly more active than taxol and promises to be active against tumours resistant to conventional antineoplastics.