Paclitaxel maintenance chemotherapy following intraperitoneal chemotherapy for ovarian cancer

Tumor suppressor genes and their underlying interactions in paclitaxel resistance in cancer therapy

Objectives

Paclitaxel (PTX) is frequently used in the clinical treatment of solid tumors. But the PTX-resistance is a great obstacle in cancer treatment. Exploration of the mechanisms of drug resistance suggests that tumor suppressor genes (TSGs) play a key role in the response of chemotherapeutic drugs. TSGs, a set of genes that are often inactivated in cancers, can regulate various biological processes. In this study, an overview of the contribution of TSGs to PTX resistance and their underlying relationship in cancers are reported by using GeneMANIA, a web-based tool for gene/protein function prediction.

Methods

Using PubMed online database and Google web site, the terms “paclitaxel resistance” or “taxol resistance” or “drug resistance” or “chemotherapy resistance”, and “cancer” or “carcinoma”, and “tumor suppressor genes” or “TSGs” or “negative regulated protein” or “antioncogenes” were searched and analyzed. GeneMANIA data base was used to predict gene/protein interactions and functions.

Results

We identified 22 TSGs involved in PTX resistance, including BRCA1, TP53, PTEN, APC, CDKN1A, CDKN2A, HIN-1, RASSF1, YAP, ING4, PLK2, FBW7, BLU, LZTS1, REST, FADD, PDCD4, TGFBI, ING1, Bax, PinX1 and hEx. The TSGs were found to have direct and indirect relationships with each other, and thus they could contribute to PTX resistance as a group. The varied expression status and regulation function of the TSGs on cell cycle in different cancers might play an important role in PTX resistance.

Conclusion

A further understanding of the roles of tumor suppressor genes in drug resistance is an important step to overcome chemotherapy tolerance. Tumor suppressor gene therapy targets the altered genes and signaling pathways and can be a new strategy to reverse chemotherapy resistance.

LZTS1 downregulation confers paclitaxel resistance and is associated with worse prognosis in breast cancer

The Leucine Zipper Tumor Suppressor 1 (LZTS1) is a tumor suppressor gene, located at chromosome 8p22, which is frequently altered in human cancer. In normal tissue, its ubiquitous expression regulates cell mitosis by the stabilization of microtubule networks. LZTS1-deficient mouse embryonic fibroblasts have been shown to have an accelerated mitotic progression, and a higher resistance to taxanes, microtubule-stabilizing drugs. We investigate the role of Lzts1 in paclitaxel-resistance in breast cancer cells. Downregulation of Lzts1 expression significantly decreases sensitivity to paclitaxel in vitro. We further analyzed Lzts1 expression by immunohistochemistry in 270 primary breast cancer samples and 16 normal breast specimens. Lzts1 was significantly downregulated in breast cancer samples and its deregulation was associated with a higher incidence of tumor recurrence, and to a worse overall survival. Moreover, Lzts1-negative tumors were associated with unfavorable outcome after taxanes-based therapy. Thus our data suggest that Lzts1 deregulation is involved in breast cancer and its immunohistochemical evaluation may serve as a prognostic factor for breast cancer therapy.

Therapeutic strategies based on polymeric microparticles

The development of the field of materials science, the ability to perform multidisciplinary scientific work, and the need for novel administration technologies that maximize therapeutic effects and minimize adverse reactions to readily available drugs have led to the development of delivery systems based on microencapsulation, which has taken one step closer to the target of personalized medicine. Drug delivery systems based on polymeric microparticles are generating a strong impact on preclinical and clinical drug development and have reached a broad development in different fields supporting a critical role in the near future of medical practice. This paper presents the foundations of polymeric microparticles based on their formulation, mechanisms of drug release and some of their innovative therapeutic strategies to board multiple diseases.

Office-based intraperitoneal chemotherapy for ovarian cancer

The challenges and opportunities when implementing an office-based intraperitoneal chemotherapy program.

Current status of maintenance therapy for advanced ovarian cancer

Even after countered with and responding to maximal surgical and chemotherapy efforts, advanced ovarian cancer usually ultimately recurs. One strategy employed to forestall recurrence is maintenance chemotherapy, an extension of treatment following a complete response to conventional measures. Many agents have been studied and many more are currently under investigation in maintenance regimens. While phase III data suggest that taxane maintenance prolongs progression-free survival, no overall survival benefit has been established. This article reviews the current status of maintenance therapy for advanced ovarian cancer, including phase III evidence and new and upcoming trials.

A review of the current evidence for maintenance therapy in ovarian cancer

OBJECTIVES

Ovarian cancer (OC) typically is diagnosed at advanced stages, in which the primary goal of therapy is to prolong progression-free survival (PFS) and overall survival (OS). In recent years, maintenance therapy has been tested for this purpose in advanced OC (AOC). Literature on maintenance therapy in AOC was systematically reviewed to assess current knowledge regarding the impact of this therapeutic approach.

METHODS

A MEDLINE search was performed 2/2009 for articles published 1/2001-1/2009 pertaining to OC maintenance therapy guidelines, patterns, and outcomes. A second search used keywords specific to maintenance and included primary studies published in the last 10 years. Of 406 sources identified, 36 primary studies and 16 review articles were included in this systematic review. A third search used the keyword "consolidation" to find maintenance articles not identified through other searches; of 48 additional sources, 13 primary studies and 6 reviews were included. A fourth search of non-MEDLINE-indexed sources yielded 14 additional relevant publications from the same time period.

RESULTS

Among practice guidelines identified, only the National Comprehensive Cancer Network (NCCN) 2008 guidelines provide recommendations regarding maintenance therapy, assigning it a category 2B recommendation. No studies were identified that reported current treatment patterns or economic outcomes in maintenance therapy; quality of life data were reported in one study. A variety of agents have been tested for maintenance, with paclitaxel the most commonly evaluated. The Southwest Oncology Group-Gynecologic Oncology Group 178 trial has found that 12 cycles of paclitaxel extend PFS (by 7 months) compared to 3 months paclitaxel, but could not adequately evaluate OS.

CONCLUSIONS

Maintenance therapy may improve clinical outcomes in AOC, but additional research is needed to demonstrate an OS advantage. Future studies should investigate the long-term clinical benefit of maintenance treatment and its impact on resource utilization and health-related quality of life.

Clinical Trial Participation Is Associated With Improved Outcome in Women With Ovarian Cancer

Objectives:

To determine the effect of participation in clinical trials on survival of women with ovarian cancer. Disease-specific factors and demographics were also examined.

Methods:

A total of 158 women were treated for ovarian cancer at a regional cancer center. All patients were offered treatment with surgery/chemotherapy and were screened at diagnosis for participation in clinical research. Progression-free and overall survival, as well as demographic- and treatment-related data, were recorded.

Results:

Fifty-three participated in clinical trials and 105 did not. On-study versus off-study subjects were similar in age (64.1 vs 63.5 years), ethnicity (87% vs 85% white), performance status (100% 0-1 Gynecologic Oncology Group scale), and urban versus rural lifestyle (58% vs 55% urban). Stage of disease, histologic subtype, and type/amount of therapy were also similar. Kaplan-Meier analysis showed superior overall survival for on-study subjects (median, 46 vs 25 months, 95% confidence interval, 1.0299-2.1505 months, P = 0.0343). A trend toward improved progression-free survival approached significance for on-study subjects (median, 23 vs 9 months, 95% confidence interval, 0.9545-2.0022 months, P = 0.0866).

Conclusions:

Women with ovarian cancer who participate in clinical trials at this institution have improved survival compared with those who are treated with standard therapies. No other factors examined were associated with treatment completion or survival. Further, participation in clinical research does not vary by age, ethnicity, urban versus rural lifestyle, or cancer stage or histologic subtype. However, disclosure of this information to potential clinical trial participants may represent an ethical conflict and should be carefully considered in light of existing ethical guidelines for human subject research.