Integrated experimental and simulation study of the response to sequential treatment with erlotinib and gemcitabine in pancreatic cancer

Continuous iontronic chemotherapy reduces brain tumor growth in embryonic avian in vivo models

Local and long-lasting administration of potent chemotherapeutics is a promising therapeutic intervention to increase the efficiency of chemotherapy of hard-to-treat tumors such as the most lethal brain tumors, glioblastomas (GBM). However, despite high toxicity for GBM cells, potent chemotherapeutics such as gemcitabine (Gem) cannot be widely implemented as they do not efficiently cross the blood brain barrier (BBB). As an alternative method for continuous administration of Gem, we here operate freestanding iontronic pumps - "GemIPs" - equipped with a custom-synthesized ion exchange membrane (IEM) to treat a GBM tumor in an avian embryonic in vivo system. We compare GemIP treatment effects with a topical metronomic treatment and observe that a remarkable growth inhibition was only achieved with steady dosing via GemIPs. Daily topical drug administration (at the maximum dosage that was not lethal for the embryonic host organism) did not decrease tumor sizes, while both treatment regimes caused S-phase cell cycle arrest and apoptosis. We hypothesize that the pharmacodynamic effects generate different intratumoral drug concentration profiles for each technique, which causes this difference in outcome. We created a digital model of the experiment, which proposes a fast decay in the local drug concentration for the topical daily treatment, but a long-lasting high local concentration of Gem close to the tumor area with GemIPs. Continuous chemotherapy with iontronic devices opens new possibilities in cancer treatment: the long-lasting and highly local dosing of clinically available, potent chemotherapeutics to greatly enhance treatment efficiency without systemic side-effects. SIGNIFICANCE STATEMENT: Iontronic pumps (GemIPs) provide continuous and localized administration of the chemotherapeutic gemcitabine (Gem) for treating glioblastoma in vivo. By generating high and constant drug concentrations near the vascularized growing tumor, GemIPs offer an efficient and less harmful alternative to systemic administration. Continuous GemIP dosing resulted in remarkable growth inhibition, superior to daily topical Gem application at higher doses. Our digital modelling shows the advantages of iontronic chemotherapy in overcoming limitations of burst release and transient concentration profiles, and providing precise control over dosing profiles and local distribution. This technology holds promise for future implants, could revolutionize treatment strategies, and offers a new platform for studying the influence of timing and dosing dependencies of already-established drugs in the fight against hard-to-treat tumors.

Two Possible Strategies for Drug Modification of Gemcitabine and Future Contributions to Personalized Medicine

Drug repurposing is an emerging strategy, which uses already approved drugs for new medical indications. One such drug is gemcitabine, an anticancer drug that only works at high doses since a portion is deactivated in the serum, which causes toxicity. In this review, two methods were discussed that could improve the anticancer effect of gemcitabine. The first is a chemical modification by conjugation with cell-penetrating peptides, namely penetratin, pVEC, and different kinds of CPP6, which mostly all showed an increased anticancer effect. The other method is combining gemcitabine with repurposed drugs, namely itraconazole, which also showed great cancer cell inhibition growth. Besides these two strategies, physiologically based pharmacokinetic models (PBPK models) are also the key for predicting drug distribution based on physiological data, which is very important for personalized medicine, so that the correct drug and dosage regimen can be administered according to each patient’s physiology. Taking all of this into consideration, it is believed that gemcitabine can be repurposed to have better anticancer effects.

Effect of Combining EGFR Tyrosine Kinase Inhibitors and Cytotoxic Agents on Cholangiocarcinoma Cells

Purpose

The potential of members of the epidermal growth factor receptor (ErbB) family as drug targets in cholangiocarcinoma (CCA) has not been extensively addressed. Although phase III clinical trials showed no survival benefits of erlotinib in patients with advanced CCA, the outcome of the standard-of-care chemotherapy treatment for CCA, gemcitabine/cisplatin, is discouraging so we determined the effect of other ErbB receptor inhibitors alone or in conjunction with chemotherapy in CCA cells.

Materials and Methods

ErbB receptor expression was determined in CCA patient tissues by immunohistochemistry and digital-droplet polymerase chain reaction, and in primary cells and cell lines by immunoblot. Effects on cell viability and cell cycle distribution of combination therapy using ErbB inhibitors with chemotherapeutic drugs was carried out in CCA cell lines. 3D culture of primary CCA cells was then adopted to evaluate the drug effect in a setting that more closely resembles in vivo cell environments.

Results

CCA tumors showed higher expression of all ErbB receptors compared with resection margins. Primary and CCA cell lines had variable expression of erbB receptors. CCA cell lines showed decreased cell viability when treated with chemotherapeutic drugs (gemcitabine and 5-fluorouracil) but also with ErbB inhibitors, particularly afatinib, and with a combination. Sequential treatment of gemcitabine with afatinib was particularly effective. Co-culture of CCA primary cells with cancer-associated fibroblasts decreased sensitivity to chemotherapies, but sensitized to afatinib.

Conclusion

Afatinib is a potential epidermal growth factor receptor targeted drug for CCA treatment and sequential treatment schedule of gemcitabine and afatinib could be explored in CCA patients.

Beyond The T/C Ratio: Old And New Anticancer Activity Scores In Vivo

Assessing the efficacy of anticancer agents in animal models remains a necessary step in the development of new treatment options and plays an important role in their optimization and comparison. Often, however, interpretation of the results is flawed by excessive trust in scores traditionally handed down, but whose origin and limitations have been lost. Here I examine the theories and assumptions underlying the most common rating scales, suggesting improvements to the old scores and proposing the adoption of multi-parameter analysis and interpretation of the results, considering different time-windows. I examined case examples of different scenarios of antiproliferative effects induced by treatment, demonstrating that common scores fail to distinguish between completely different responses to treatment or, in other circumstances, indicate a different outcome when the response is the same. I found that a combination of parameters, including the percent tumor growth between the start and end of treatment, the relative tumor burden at nadir and the absolute growth delay, may distinguish among the different cases and support a correct interpretation of the antitumor response. All these parameters can be derived from individual tumor growth curves in a simple way, without any change to common experimental procedures.

The NCI Transcriptional Pharmacodynamics Workbench: A Tool to Examine Dynamic Expression Profiling of Therapeutic Response in the NCI-60 Cell Line Panel

: The intracellular effects and overall efficacies of anticancer therapies can vary significantly by tumor type. To identify patterns of drug-induced gene modulation that occur in different cancer cell types, we measured gene-expression changes across the NCI-60 cell line panel after exposure to 15 anticancer agents. The results were integrated into a combined database and set of interactive analysis tools, designated the NCI Transcriptional Pharmacodynamics Workbench (NCI TPW), that allows exploration of gene-expression modulation by molecular pathway, drug target, and association with drug sensitivity. We identified common transcriptional responses across agents and cell types and uncovered gene-expression changes associated with drug sensitivity. We also demonstrated the value of this tool for investigating clinically relevant molecular hypotheses and identifying candidate biomarkers of drug activity. The NCI TPW, publicly available at https://tpwb.nci.nih.gov, provides a comprehensive resource to facilitate understanding of tumor cell characteristics that define sensitivity to commonly used anticancer drugs. SIGNIFICANCE: The NCI Transcriptional Pharmacodynamics Workbench represents the most extensive compilation to date of directly measured longitudinal transcriptional responses to anticancer agents across a thoroughly characterized ensemble of cancer cell lines.

Investigation on Physicochemical Characteristics of a Nanoliposome-Based System for Dual Drug Delivery

Synergistic effects of multiple drugs with different modes of action are utilized for combinatorial chemotherapy of intractable cancers. Translation of in vitro synergistic effects into the clinic can be realized using an efficient delivery system of the drugs. Despite a few studies on nano-sized liposomes containing erlotinib (ERL) and doxorubicin (DOX) in a single liposome vesicle, reliable and reproducible preparation methods as well as physicochemical characteristics of a non-PEGylated nanoliposome co-encapsulated with ERL and DOX have not been yet elucidated. In this study, ERL-encapsulated nanoliposomes were prepared using the lipid film-hydration method. By ultrasonication using a probe sonicator, the liposome diameter was reduced to less than 200 nm. DOX was loaded into the ERL-encapsulated nanoliposomes using ammonium sulfate (AS)-gradient or pH-gradient method. Effects of DOX-loading conditions on encapsulation efficiency (EE) of the DOX were investigated to determine an efficient drug-loading method. In the EE of DOX, AS-gradient method was more effective than pH gradient. The dual drug-encapsulated nanoliposomes had more than 90% EE of DOX and 30% EE of ERL, respectively. Transmission electron microscopy and selected area electron diffraction analyses of the dual drug-encapsulated nanoliposomes verified the highly oriented DOX-sulfate crystals inside the liposome as well as the less oriented small crystals of ERL in the outermost region of the nanoliposome. The nanoliposomes were stable at different temperatures without an increase of the nanoliposome diameter. The dual drug-encapsulated nanoliposomes showed a time-differential release of ERL and DOX, implying proper sequential releases for their synergism. The preparation methods and the physicochemical characteristics of the dual drug delivery system contribute to the development of the optimal process and more advanced systems for translational researches.

Delayed Sequential Co-Delivery of Gefitinib and Doxorubicin for Targeted Combination Chemotherapy

There are an increasing number of studies showing the order of drug presentation plays a critical role in achieving optimal combination therapy. Here, a nanoparticle design is presented using ion pairing and drug-polymer conjugate for the sequential delivery of gefitinib (Gi) and doxorubicin (Dox) targeting epidermal growth factor receptor (EGFR) signaling applicable for the treatment of triple negative breast cancers. To realize this nanoparticle design, Gi complexed with dioleoyl phosphatidic acid (DOPA) via ion paring was loaded onto the nanoparticle made of Dox-conjugated poly(l-lactide)-block-polyethylene glycol (PLA-b-PEG) and with an encapsulation efficiency of ∼90%. The nanoparticle system exhibited a desired sequential release of Gi followed by Dox, as verified through release and cellular uptake studies. The nanoparticle system demonstrated approximate 4-fold and 3-fold increases in anticancer efficacy compared to a control group of Dox-PLA-PEG conjugate against MDA-MB-468 and A549 cell lines in terms of half maximal inhibitory concentration (IC50), respectively. High tumor accumulation of the nanoparticle system was also substantiated for potential in vivo applicability by noninvasive fluorescent imaging.