Extreme drug resistance is common after prior exposure to paclitaxel

Nano-Drug Delivery Systems Based on Natural Products

Natural products have proven to have significant curative effects and are increasingly considered as potential candidates for clinical prevention, diagnosis, and treatment. Compared with synthetic drugs, natural products not only have diverse structures but also exhibit a range of biological activities against different disease states and molecular targets, making them attractive for development in the field of medicine. Despite advancements in the use of natural products for clinical purposes, there remain obstacles that hinder their full potential. These challenges include issues such as limited solubility and stability when administered orally, as well as short durations of effectiveness. To address these concerns, nano-drug delivery systems have emerged as a promising solution to overcome the barriers faced in the clinical application of natural products. These systems offer notable advantages, such as a large specific surface area, enhanced targeting capabilities, and the ability to achieve sustained and controlled release. Extensive in vitro and in vivo studies have provided further evidence supporting the efficacy and safety of nanoparticle-based systems in delivering natural products in preclinical disease models. This review describes the limitations of natural product applications and the current status of natural products combined with nanotechnology. The latest advances in nano-drug delivery systems for delivery of natural products are considered from three aspects: connecting targeting warheads, self-assembly, and co-delivery. Finally, the challenges faced in the clinical translation of nano-drugs are discussed.

Gynecologic and Breast Cancers: What's New in Chemoresistance and Chemosensitivity Tests?

Gynecological and breast cancers affect women's health worldwide. Although chemotherapy is one of the principal treatments for cancer, it also has limitations owing to toxicity and tumor resistance to the drugs used. Thus, individualized treatment based on personal tumor characteristics is essential for improving therapeutic outcomes and patient survival. Chemoresistance and chemosensitivity tests can be useful for predicting tumor response and guiding chemotherapy choices. This methodology has already been applied to breast, ovarian, cervical, and endometrial cancers, identifying successfully which drugs cause resistance and sensitivity responses for each individual person, influencing their progression-free survival and overall response. In addition, more recent techniques, such as organoids and patient-derived xenografts, can also recapitulate patients' tumor characteristics and contribute to chemo response evaluation. Therefore, this review compiles information on chemoresistance and chemosensitivity tests performed in gynecologic and breast cancers and their main results for women's health improvement.

Tumor-targeting peptide functionalized PEG-PLA micelles for efficient drug delivery

Because of their excellent capacity to significantly improve the bioavailability and solubility of chemotherapy drugs, block copolymer micelles are widely utilized for chemotherapy drug delivery. In order to further improve the anti-tumor ability and reduce unwanted side effects of drugs, tumor-targeting peptides were used to functionalize the surface of polymer micelles so that the micelles can target tumor tissues. Herein, we synthesized a kind of PEG-PLA that is maleimide-terminated and then conjugated with a specific peptide F3 which revealed specific capacity binding to nucleolin that is overexpressed on the surface of many tumor cells. Then, F3 conjugated, paclitaxel loaded nanoparticles (F3-NP-PTX) were prepared as stable micelles that displayed an enhanced accumulation via a peptide-mediated cellular association in human breast cancer cells (MCF-7). Furthermore, F3-NP-PTX showed a prominent anti-tumor efficacy compared with non-targeting nanoparticles (NP-PTX) both in vitro and in vivo, and showed great potential as an efficacious targeting drug delivery system for breast cancer treatment.

In vitro chemoresponse in metachronous pairs of gyneclologic cancers

Background

While most gynecologic cancers respond to first-line cytotoxic chemotherapy, treatment of recurrent disease is frequently associated with acquired drug resistance. In order to find an in vitro surrogate of this clinical phenomenon, a tumor chemoresponse assay was studied.

Methods/Materials

Patients who had tissue submitted for repeated chemoresponse testing were identified through a retrospective search. Sixty-three patients met inclusion criteria (chemoresponse testing completed at primary diagnosis and upon recurrence of disease and assays completed ≥90 days apart). The Wilcoxon signed-rank test was used to compare chemoresponse, represented as a response index (RI), between primary and recurrent measurements. In a secondary analysis, response was categorized and coded as Responsive = 3, Intermediately Responsive = 2 and Non-Responsive = 1, and the paired t-test was used to compare chemoresponse between primary and recurrent measurement.

Results

Median time between primary and recurrent tumor testing was 309 days (IQR 208–422). Drugs tested included carboplatin, cisplatin, docetaxel, doxorubicin, gemcitabine, paclitaxel, topotecan, and combination carboplatin/gemcitabine and carboplatin/paclitaxel. There were no differences in chemoresponse between primary and recurrent measurement when chemoresponse was represented by RI scores; although a trend toward increased resistance to paclitaxel upon recurrence was noted. When chemoresponse was analyzed as a continuous variable corresponding to categorized response, a significant shift toward increased resistance to paclitaxel at recurrence, and a marginally significant trend toward increased resistance to carboplatin at recurrence, were observed.

Conclusions

We observed a trend toward increased chemoresistance at recurrence for paclitaxel, and a marginally significant trend toward increased chemoresistance to carboplatin, but no change in chemoresponsiveness between primary diagnosis and recurrence of disease for other common chemotherapy drugs, including common second-line agents such as doxorubicin, gemcitabine, and topotecan.

Glycyrrhetinic acid-graft-hyaluronic acid conjugate as a carrier for synergistic targeted delivery of antitumor drugs

Glycyrrhetinic acid-graft-hyaluronic acid (HGA) conjugate was synthesized as a carrier for intravenous administration of paclitaxel (PTX), which combined hyaluronic acid (HA) and glycyrrhetinic acid (GA) as the active targeting ligands to liver tumor. In the present study, physicochemical characteristics, cellular uptake efficiency, and in vivo fates of HGA conjugates were investigated. HGA nanoparticles could readily load PTX with high efficiency up to 31.16 wt.% and entrapment efficiency to 92.02%. Moreover, PTX-loaded HGA nanoparticles exhibited more significant cytotoxicity to HepG2 cells than B16F10 cells due to simultaneously over-expressing HA and GA receptors. Meanwhile, the cellular uptake of nanoparticles was clearly enhanced in HepG2 and B16F10 cells compared to a normal fibroblast cell (HELF cells). In particular, more HGA nanoparticles were taken up by HepG2 cells than by B16F10 cells, which might be attributed to the affinity of multiple ligands of HA and GA to HepG2 cells. Furthermore, liver and tumor targeting activity of HGA nanoparticles was also confirmed by in vivo imaging analysis. The fluorescence signals of DiR-labeled HGA nanoparticles in tumor and liver were 2.88 and 1.83 folds stronger than that of the control, respectively. These results indicate HGA nanoparticles can be a potential drug carrier with "double target sites" for liver cancer therapy.

Extreme drug resistance assay results do not influence survival in women with epithelial ovarian cancer

OBJECTIVES

Extreme drug resistance (EDR) assays have been used to identify chemotherapy regimens that are least likely to be of clinical benefit in the treatment of epithelial ovarian cancer (EOC). We sought to examine the impact of EDR assay-guided therapy on the outcome of patients with EOC in the primary and recurrent settings.

METHODS

We conducted a retrospective review of demographic, pathologic, EDR assay and clinical outcome data from 377 patients with EOC who had an assay sent at the time of their primary or subsequent cytoreductive surgeries. Multivariate analyses were performed using Cox proportional hazards method to identify and estimate the impact of independent prognostic factors on time to progression (TTP), overall survival (OS) and survival after recurrence (RS).

RESULTS

Increasing age was associated with a worse OS and RS (HR=1.34; 95% CI, 1.14-1.58 and HR=1.14; 95% CI, 1.00-1.31, respectively for each decade increase in age). Surgical outcome in the setting of primary or secondary cytoreduction remained an important predictor of survival. Compared with patients with microscopic residual disease, patients who were left with 0.1 to 1.0 cm and >1.0 cm residual disease had an increased risk of recurrence (HR=1.94; 95% CI, 1.33 to 2.84 and HR=3.61; 95% CI; 2.07 to 6.39, respectively) and death (HR=1.59; 95% CI, 1.03 to 2.45; and HR=2.14; 95% CI, 1.09 to 4.20, respectively). For patients who recurred, those who did not undergo secondary cytoreductive surgery and patients who were left with >1.0 cm residual had an increased risk of death compared to patients with microscopic residual (HR=2.13; 95% CI, 1.28 to 3.54; and HR=2.84; 95% CI, 1.71 to 4.71, respectively). EDR assay results analyzed for single agents or combinations of chemotherapies failed to independently predict patient outcomes no matter if the assay was performed at the time of the primary surgery or recurrence.

CONCLUSION

EDR assay results do not independently predict or alter the outcomes of patients with EOC who are treated with the current standards of primary cytoreductive surgery followed by platinum and taxane combination chemotherapy.

In vitro extreme drug resistance assay to taxanes or platinum compounds for the prediction of clinical outcomes in epithelial ovarian cancer: a prospective cohort study

PURPOSE

We sought to investigate the efficacy of in vitro extreme drug resistance (EDR) assay for the prediction of drug response, platinum-resistance (progression-free survival, PFS <6 months) and survival in patients with epithelial ovarian cancer (EOC) who received taxane- and platinum-based chemotherapy after surgery.

METHODS

Between December 2005 and August 2007, 43 patients were enrolled prospectively. They underwent staging laparotomy followed by six or nine cycles of taxane- and platinum-based chemotherapy, and their tumors were submitted for in vitro EDR assay to taxanes (paclitaxel or docetaxel) and platinum compounds (carboplatin or cisplatin).

RESULTS

The rates of EDR to taxanes and platinum compounds were 20.9% (9/43) and 23.3% (10/43). Patients with EDR to platinum compounds showed a lower rate of overall response (60 vs. 100%), a higher rate of platinum-resistance (50 vs. 18.2%) and poor overall survival (OS) (median OS; 29.2 vs. 33.7 months) than those without EDR to platinum compounds (P < 0.05), whereas patients with EDR to taxanes showed poor PFS than those without EDR to taxanes (12.5 vs. 19 months, P < 0.01). Moreover, suboptimal debulking surgery and EDR to taxanes were poor prognostic factors for PFS (adjusted hazard ratio 3.215 and 3.984; 95% confidence interval 1.845-7.895 and 3.814-11.674, respectively) although there was no independent risk factor for poor OS by the multivariate Cox's proportional hazard analysis.

CONCLUSIONS

In vitro EDR assay to taxanes and platinum compounds may be helpful for predicting drug response, platinum-resistance and survival in patients with EOC who received taxane- and platinum-based chemotherapy after staging laparotomy.

In vitro assays for the evaluation of drug resistance in tumor cells

Oncologic diseases are among leading cause of mortality in developed countries. Despite significant progress, the use of standard cytotoxic chemotherapy has reached a therapeutical plateau. Currently, the process of selecting chemotherapy represents a trial and error method neglecting biological individuality of tumor and its bearer. The improvement of treatment results is expected from ex vivo drug sensitivity testing which may allow to choose the most effective drug for individual patient and to exclude agents to which the tumor cells exert resistance. New techniques and rapidly increasing knowledge about the molecular basis of malignant diseases provide important opportunities for the future of chemotherapy. This paper reviews current methods used to test the resistance of tumor cells to a panel of anticancer agents in vitro. In addition, we focused on the in vitro MTT assay which represents one of major technique for testing of tumor cell resistance to anticancer agents.