Paclitaxel Through the Ages of Anticancer Therapy: Exploring Its Role in Chemoresistance and Radiation Therapy

Low-dose paclitaxel downregulates MYC proto-oncogene bHLH transcription factor expression in colorectal carcinoma cells

Paclitaxel (PTX) has been commonly used to treat multiple types of tumor. Its anticancer mechanism differs based on different PTX concentrations and types of tumor cell. In the present study, MTT assays of HCT116 and LOVO cells treated with PTX revealed the chemosensitivity of the cell lines for different PTX concentrations. The half-maximal inhibitory concentration values of PTX for these cells were 2.46 and 2.24 nM, respectively. Cell morphology observation revealed that both cell lines exhibited rounded, wrinkled and damaged morphologies with increasing concentrations of PTX. Fluorescence-activated cell sorting analysis indicated that 1 nM PTX increased the proportion of cells in sub-G₁ phases and decreased the proportion of cells in G₀/G₁ phases, whereas the proportions of cells in S and G₂/M phases only slightly changed for both cell lines. Western blot analysis indicated that the total/nuclear protein expression of MYC proto-oncogene bHLH transcription factor (c-Myc) and phosphorylated (P)-c-Myc decreased in HCT116 cells in a dose-dependent manner, whereas the nuclear protein expression of P-c-Myc increased in LOVO cells in a dose-dependent manner. These results suggest that low-dose PTX downregulates c-Myc and P-c-Myc expression, subsequently inhibiting the cell cycle at G₀/G₁ in colorectal carcinoma.

Therapeutic targeting of oncogenic transcription factors by natural products in eye cancer

Carcinogenesis has a multifactorial etiology, and the underlying molecular pathogenesis is still not entirely understood, especially for eye cancers. Primary malignant intraocular neoplasms are relatively rare, but delayed detection and inappropriate management contribute to poor outcomes. Conventional treatment, such as orbital exenteration, chemotherapy, or radiotherapy, alone results in high mortality for many of these malignancies. Recent sequential multimodal therapy with a combination of high-dose chemotherapy, followed by appropriate surgery, radiotherapy, and additional adjuvant chemotherapy has helped dramatically improve management. Transcription factors are proteins that regulate gene expression by modulating the synthesis of mRNA. Since transcription is a dominant control point in the production of many proteins, transcription factors represent key regulators for numerous cellular functions, including proliferation, differentiation, and apoptosis, making them compelling targets for drug development. Natural compounds have been studied for their potential to be potent yet safe chemotherapeutic drugs. Since the ancient times, plant-derived bioactive molecules have been used to treat dreadful diseases like cancer, and several refined pharmaceutics have been developed from these compounds. Understanding targeting mechanisms of oncogenic transcription factors by natural products can add to our oncologic management toolbox. This review summarizes the current findings of natural products in targeting specific oncogenic transcription factors in various types of eye cancer.

miR-339-5p downregulation contributes to Taxol resistance in small-cell lung cancer by targeting α1,2-fucosyltransferase 1

Lung cancer is a leading cause of cancer-related mortality, and non-small-cell lung carcinoma is responsible for almost 80% of lung cancer-related deaths. In recent years, lung cancer has shown increasing incidence but poor prognosis, and many studies have demonstrated that microRNAs play crucial roles in the development of lung carcinoma and chemoresistance. This study investigated the role of miR-339-5p involvement in lung carcinoma cell lines and chemoresistance to Taxol. We observed that miR-339-5p was significantly downregulated in Taxol-A549 cells compared with A549 cells. In vitro studies further indicated that miR-339-5p could promote colony formation and attenuate apoptosis of lung carcinoma cell lines through targeting α1,2-fucosyltransferase 1 and regulation of the downstream protein Lewis y. Furthermore, miR-339-5p was found to enhance the proliferation inhibition ability of Taxol in lung carcinoma cell lines as well as in the Taxol-A549 subclone. An in vivo study indicated that both miR-339-5p and Taxol could attenuate the growth of lung carcinoma; moreover, miR-339-5p could synergistically promote this inhibitory function of Taxol. In summary, our results suggest a miR-339-5p molecular network that is involved in controlling lung carcinoma progression. © 2017 The Authors IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 69(11):841-849, 2017.

Meta-analysis of the effects of oral and intravenous dexamethasone premedication in the prevention of paclitaxel-induced allergic reactions

Background

Dexamethasone premedication is required to prevent paclitaxel-related hypersensitivity reactions (HSRs). Oral dexamethasone (PO-D) has been considered the standard premedication regimen. However, whether intravenous dexamethasone (IV-D) is feasible for preventing paclitaxel-related HSRs is still unclear. We conducted a meta-analysis to compare these two regimens.

Methods

We performed a systematic search in the PubMed, China National Knowledge Infrastructure, and Web of Science databases for relevant articles published before June 2016. Outcomes included HSRs and severe HSRs. Statistical analyses were performed using RevMan 5.2 software.

Result

Six studies comprising 1347 patients were included in the meta-analysis. The PO-D premedication regimen showed a significantly decreased incidence of severe HSRs compared with the IV-D regimen with an OR of 0.53 (95% CI 0.28-0.99, p = 0.05). However, there was no difference in the overall paclitaxel-related HSR rates between the two premedication regimens (OR 0.76, 95% CI 0.55-1.06, p = 0.11). Subgroup analyses according to study type and country of origin showed similar statistical results between the two premedication regimens.

Conclusion

Our meta-analysis showed that the PO-D premedication regimen is superior to the IV-D regimen in preventing paclitaxel-related HSRs. Additional randomized controlled trials are needed to confirm our findings.

Inhibition of the Receptor Tyrosine Kinase AXL Restores Paclitaxel Chemosensitivity in Uterine Serous Cancer

Uterine serous cancer (USC) is aggressive, and the majority of recurrent cases are chemoresistant. Because the receptor tyrosine kinase AXL promotes invasion and metastasis of USC and is implicated in chemoresistance in other cancers, we assessed the role of AXL in paclitaxel resistance in USC, determined the mechanism of action, and sought to restore chemosensitivity by inhibiting AXL in vitro and in vivo We used short hairpin RNAs and BGB324 to knock down and inhibit AXL. We assessed sensitivity of USC cell lines to paclitaxel and measured paclitaxel intracellular accumulation in vitro in the presence or absence of AXL. We also examined the role of the epithelial-mesenchymal transition (EMT) in AXL-mediated paclitaxel resistance. Finally, we treated USC xenografts with paclitaxel, BGB324, or paclitaxel plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant USC patient tumors and cell lines than in chemosensitive tumors and cell lines. Knockdown or inhibition of AXL increased sensitivity of USC cell lines to paclitaxel in vitro and increased cellular accumulation of paclitaxel. AXL promoted chemoresistance even in cells that underwent the EMT in vitro Finally, in vivo studies of combination treatment with BGB324 and paclitaxel showed a greater than 51% decrease in tumor volume after 2 weeks of treatment when compared with no treatment or single-agent treatments (P < 0.001). Our results show that AXL expression mediates chemoresistance independent of EMT and prevents accumulation of paclitaxel. This study supports the continued investigation of AXL as a clinical target, particularly in chemoresistant USC. Mol Cancer Ther; 16(12); 2881-91. ©2017 AACR.

A hindsight reflection on the clinical studies of poly(l-glutamic acid)-paclitaxel

Chemotherapy for cancer treatment is limited by the excessive toxicity to normal tissues. The design of chemodrug-loaded nanoformulations provides a unique approach to improve the treatment efficacy while minimizing toxicity. Despite the numerous publications of nanomedicine for the last several decades, however, only a small fraction of the developed nanoformulations have entered clinical trials, with even fewer being approved for clinical application. Poly(l-glutamic acid)-paclitaxel (PG-TXL) belongs to the few formulations that reached phase III clinical trials. Unfortunately, the development of PG-TXL stopped in 2016 due to the inability to show significant improvement over current standard care. This review will provide an overview of the preclinical and clinical evaluations of PG-TXL, and discuss lessons to be learned from this ordeal. The precise identification of suitable patients for clinical trial studies, deep understanding of the mechanisms of action, and an effective academic-industry partnership throughout all phases of drug development are important for the successful bench-to-bedside translation of new nanoformulations. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Peptide-Based Structures.

Fighting tubulin-targeting anticancer drug toxicity and resistance

Tubulin-targeting drugs, like taxanes and vinca alkaloids, are among the most effective anticancer therapeutics used in the clinic today. Specifically, anti-microtubule cancer drugs (AMCDs) have proven to be effective in the treatment of castration-resistant prostate cancer and triple-negative breast cancer. AMCDs, however, have limiting toxicities that include neutropenia and neurotoxicity, and, in addition, tumor cells can become resistant to the drugs after long-term use. Co-targeting mitotic progression/slippage with inhibition of the protein kinases WEE1 and MYT1 that regulate CDK1 kinase activity may improve AMCD efficacy, reducing the acquisition of resistance by the tumor and side effects from the drug and/or its vehicle. Other possible treatments that improve outcomes in the clinic for these two drug-resistant cancers, including new formulations of the AMCDs and pursuing different molecular targets, will be discussed.

Novel quinolone chalcones targeting colchicine-binding pocket kill multidrug-resistant cancer cells by inhibiting tubulin activity and MRP1 function

Agents targeting colchicine-binding pocket usually show a minimal drug-resistance issue, albeit often associated with high toxicity. Chalcone-based compounds, which may bind to colchicine-binding site, are found in many edible fruits, suggesting that they can be effective drugs with less toxicity. Therefore, we synthesized and examined 24 quinolone chalcone compounds, from which we identified ((E)-3-(3-(2-Methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-17) and ((E)-6-Methoxy-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-20) as promising leads. In particular, CTR-20 was effective against 65 different cancer cell lines originated from 12 different tissues, largely in a cancer cell-specific manner. We found that both CTR-17 and CTR-20 reversibly bind to the colchicine-binding pocket on β-tubulin. Interestingly however, both the CTRs were highly effective against multidrug-resistant cancer cells while colchicine, paclitaxel and vinblastine were not. Our study with CTR-20 showed that it overcomes multidrug-resistance through its ability to impede MRP1 function while maintaining strong inhibition against microtubule activity. Data from mice engrafted with the MDA-MB-231 triple-negative breast cancer cells showed that both CTR-17 and CTR-20 possess strong anticancer activity, alone or in combination with paclitaxel, without causing any notable side effects. Together, our data demonstrates that both the CTRs can be effective and safe drugs against many different cancers, especially against multidrug-resistant tumors.

Unmonitored use of herbal medicine by patients with breast cancer: reframing expectations

PURPOSE

To identify the unmonitored use of herbal medicine by female patients with breast cancer, examining the impact of an integrative physician (IP) consultation on this practice.

METHODS

The files of 269 female patients with breast cancer following an IP consultation were surveyed retrospectively for use of herbal medicine for cancer-related goals. Expectations from the IP consultation and adherence to the IP-guided treatments were examined as well.

RESULTS

Among the cohort, 111 (41.3%) reported using herbal medicine for cancer-related goals, unmonitored by their oncology healthcare professional. Factors predicting herbal medicine use were the adoption of dietary changes (odds ratio = 13.6, p < 0.001, CI 7.16-26.0) and the expectation that the IP consultation and treatments would address cancer-related goals (odds ratio = 3.29, p = 0.001, CI 1.64-6.6). Patients with metastatic disease were more likely to be using herbal medicine than non-users (34.5 vs. 22.8%; p = 0.088), as were those who had consulted with a complementary/alternative medicine practitioner (54.9 vs. 20.8%; p = 0.005). The IP advised 17 patients (15.3%) to stop taking specific herbal products due to safety-related concerns; and 10 patients to take dietary supplements for relief of specific symptoms. Herbal medicine users were less likely than non-users to adhere to the IP-recommended treatment program (34.7 vs. 48.3%; p = 0.037).

CONCLUSIONS

Unmonitored use of herbal medicine by patients with breast cancer is more frequent among those adopting dietary changes for cancer-related goals. Integrative physicians provide evidence-based guidance on the safe and effective use of herbal products, and reframe patient expectations from cancer-related goals to reducing symptoms and improving quality of life.

Omega-3 Fatty Acid Grafted PAMAM-Paclitaxel Conjugate Exhibits Enhanced Anticancer Activity in Upper Gastrointestinal Cancer Cells

Upper Gastrointestinal Cancers (UGCs) are a leading cause of cancer-related deaths worldwide. Paclitaxel (PTX) is frequently used for the treatment of UGCs; however, low bioavailability, reduced solubility, and dose-dependent toxicity impede its therapeutic use. PAMAMG_4.0 -NH₂ -DHA is synthesized by linking amine-terminated fourth-generation poly(amidoamine) (PAMAMG_4.0 -NH₂ ) dendrimers with omega-3 fatty acid docosahexaenoic acid (DHA). Next, PAMAMG_4.0 -NH₂ -DHA-PTX (DHATX) and PAMAMG_4.0 -NH₂ -PTX (PAX) conjugates are synthesized by subsequent covalent binding of PTX with PAMAMG_4.0 -NH₂ -DHA and PAMAMG_4.0 -NH₂ , respectively. ¹ H-NMR and MALDI-TOF analyses are performed to confirm conjugation of DHA to PAMAMG_4.0 -NH₂ and PTX to PAMAMG_4.0 -NH₂ -DHA. The cell viability, clonogenic cell survival, and flow cytometry analyses are used to determine the anticancer activity of PTX, PAX, and DHATX in UGC cell lines. The in vitro data indicate that treatment with DHATX is significantly more potent than PTX or PAX at inhibiting cellular proliferation, suppressing long-term survival, and inducing cell death in UGC cells.

Low-Dose Paclitaxel Inhibits Tumor Cell Growth by Regulating Glutaminolysis in Colorectal Carcinoma Cells

Paclitaxel (PTX) is a natural alkaloid isolated from the bark of a tree, Taxus brevifolia, and is currently used to treat a variety of tumors. Recently, it has been found that low-dose PTX is a promising treatment for some cancers, presenting few side effects. However, antitumor mechanisms of low-dose PTX (<1 nM) have rarely been illuminated. Here we report a new antitumor mechanism of low-dose PTX in colorectal carcinoma cells. We treated colorectal carcinoma HCT116 cells with PTX at 0.1 and 0.3 nM for 0, 1, 2, or 3 days, and found that low-dose PTX inhibits cell growth without altering cell morphology and cell cycle. There was a significant decrease of pH in culture media with 0.3 nM PTX for 3 days. Also, lactate production was significantly increased in a dose- and time-dependent manner. Furthermore, expression of glutaminolysis-related genes GLS, SLC7A11 and SLC1A5 were significantly decreased in the colorectal carcinoma cells treated with low-dose PTX. Meanwhile, protein expression levels of p53 and p21 increased significantly in colorectal carcinoma cells so treated. In summary, low-dose PTX down-regulated glutaminolysis-related genes and increased their lactate production, resulting in decreased pH of tumor microenvironments and inhibition of tumor cell growth. Up-regulation of p53 and p21 in colorectal carcinoma cells treated with low-dose PTX also contributed to inhibition of tumor cell growth.

Technetium-99m radiolabeled paclitaxel as an imaging probe for breast cancer in vivo

The high incidence and mortality of breast cancer supports efforts to develop innovative imaging probes to effectively diagnose, evaluate the extent of the tumor, and predict the efficacy of tumor treatments while concurrently and selectively delivering anticancer agents to the cancer tissue. In the present study we described the preparation of technetium-99m (99mTc)-labeled paclitaxel (PTX) and evaluated its feasibility as a radiotracer for breast tumors (4T1) in BALB/c mice. Thin Layer Chromatography (TLC) was used to determine the radiochemical purity and in vitro stability of 99mTc-PTX. PTX micelles showed a unimodal distribution with mean diameter of 13.46±0.06nm. High radiochemical purity (95.8±0.3%) and in vitro stability (over than 95%), up to 24h, were observed. Blood circulation time of 99mTc-PTX was determined in healthy BALB/c mice. 99mTc-PTX decays in a one-phase manner with a half-life of 464.3 minutes. Scintigraphic images and biodistribution were evaluated at 4, 8 and 24h after administration of 99mTc-PTX in 4T1 tumor-bearing mice. The data showed a significant uptake in the liver, spleen and kidneys, due to the importance of these routes for excretion. Moreover, high tumor uptake was achieved, indicated by high tumor-to-muscle ratios. These findings indicate the usefulness of 99mTc-PTX as a radiotracer to identify 4T1 tumor in animal models. In addition, 99mTc-PTX might be used to follow-up treatment protocols in research, being able to provide information about tumor progression after therapy.

Bone morphogenetic protein 4 is overexpressed in and promotes migration and invasion of drug-resistant cancer cells

Drug resistance and metastasis significantly hinder chemotherapy and worsen prognoses in cancer. Bone morphogenetic protein 4 (BMP4) belongs to the TGF-β superfamily, has broad biological activities in cell proliferation and cartilage differentiation and is also able to induce migration and invasion. Herein, we investigated the role of BMP4 in the regulation of metastasis in paclitaxel-resistant human esophageal carcinoma EC109 cells (EC109/Taxol) and docetaxel-resistant human gastric cancer MGC803 cells (MGC/Doc). In these drug-resistant cell lines, we found the cell motility was enhanced and BMP4 was up-regulated relative to their respective parental cell lines. Consistent with in vitro assays, migration potential and BMP4 expression were increased in EC109/Taxol nude mice. Furthermore, to address whether BMP4 was required to enhance the metastatic in EC109/Taxol cells, the pharmacological inhibitor of BMP signaling dorsomorphin was used; meanwhile, we found that the migration and invasion abilities were inhibited. Moreover, the canonical Smad signaling pathway was investigated. Overall, our studies demonstrated that BMP4 participates in the regulation of invasion and migration by EC109/Taxol cells, and inhibition of BMP4 may be a novel strategy to interfere with metastasis in cancer therapy.

Targeted delivery of paclitaxel and doxorubicin to cancer xenografts via the nanoparticle of nano-diamino-tetrac

The tetraiodothyroacetic acid (tetrac) component of nano-diamino-tetrac (NDAT) is chemically bonded via a linker to a poly(lactic-co-glycolic acid) nanoparticle that can encapsulate anticancer drugs. Tetrac targets the plasma membrane of cancer cells at a receptor on the extracellular domain of integrin αvβ3. In this study, we evaluate the efficiency of NDAT delivery of paclitaxel and doxorubicin to, respectively, pancreatic and breast cancer orthotopic nude mouse xenografts. Intra-tumoral drug concentrations were 5-fold (paclitaxel; P<0.001) and 2.3-fold (doxorubicin; P<0.01) higher than with conventional systemic drug administration. Tumor volume reductions reflected enhanced xenograft drug uptake. Cell viability was estimated by bioluminescent signaling in pancreatic tumors and confirmed an increased paclitaxel effect with drug delivery by NDAT. NDAT delivery of chemotherapy increases drug delivery to cancers and increases drug efficacy.

Targeted delivery of cisplatin to tumor xenografts via the nanoparticle component of nano-diamino-tetrac

Aim: Nano-diamino-tetrac (NDAT) targets a receptor on integrin αvβ3; αvβ3 is generously expressed by cancer cells and dividing endothelial cells and to a small extent by nonmalignant cells. The tetrac (tetraiodothyroacetic acid) of NDAT is covalently bound to a poly(lactic-co-glycolic acid) nanoparticle that encapsulates anticancer drugs. We report NDAT delivery efficiency of cisplatin to agent-susceptible urinary bladder cancer xenografts. Materials & methods: Cisplatin-loaded NDAT (NDAT-cisplatin) was administered to xenograft-bearing nude mice. Tumor size response and drug content were measured. Results: Intratumoral drug concentration was up to fivefold higher (p < 0.001) in NDAT-cisplatin-exposed lesions than with conventional systemic administration. Tumor volume reduction achieved was NDAT-cisplatin > NDAT without cisplatin > cisplatin alone. Conclusion: NDAT markedly enhances cisplatin delivery to urinary bladder cancer xenografts and increases drug efficacy.

Bone Microenvironment Changes in Latexin Expression Promote Chemoresistance

Although docetaxel is the standard of care for advanced prostate cancer, most patients develop resistance to docetaxel. Therefore, elucidating the mechanism that underlies resistance to docetaxel is critical to enhance therapeutic intervention. Mining cDNA microarray from the PC-3 prostate cancer cell line and its docetaxel-resistant derivative (PC3-TxR) revealed decreased latexin (LXN) expression in the resistant cells. LXN expression was inversely correlated with taxane resistance in a panel of prostate cancer cell lines. LXN knockdown conferred docetaxel resistance to prostate cancer cells in vitro and in vivo, whereas LXN overexpression reduced docetaxel resistance in several prostate cancer cell lines. A mouse model of prostate cancer demonstrated that prostate cancer cells developed resistance to docetaxel in the bone microenvironment, but not the soft tissue microenvironment. This was associated with decreased LXN expression in prostate cancer cells in the bone microenvironment compared with the soft tissue microenvironment. It was identified that bone stromal cells decreased LXN expression through methylation and induced chemoresistance in prostate cancer in vitro These findings reveal that a subset of prostate cancer develops docetaxel resistance through loss of LXN expression associated with methylation and that the bone microenvironment promotes this drug resistance phenotype.Implications: This study suggests that the LXN pathway should be further explored as a viable target for preventing or reversing taxane resistance in prostate cancer. Mol Cancer Res; 15(4); 457-66. ©2017 AACR.

PARP inhibitor combination therapy

In 2014, olaparib (Lynparza) became the first PARP (Poly(ADP-ribose) polymerase) inhibitor to be approved for the treatment of cancer. When used as single agents, PARP inhibitors can selectively target tumour cells with BRCA1 or BRCA2 tumour suppressor gene mutations through synthetic lethality. However, PARP inhibition also shows considerable promise when used together with other therapeutic agents. Here, we summarise both the pre-clinical and clinical evidence for the utility of such combinations and discuss the future prospects and challenges for PARP inhibitor combinatorial therapies.

Microtubule-based force generation

Microtubules are vital to many important cell processes, such as cell division, transport of cellular cargo, organelle positioning, and cell migration. Owing to their diverse functions, understanding microtubule function is an important part of cell biological research that can help in combating various diseases. For example, microtubules are an important target of chemotherapeutic drugs such as paclitaxel because of their pivotal role in cell division. Many functions of microtubules relate to the generation of mechanical forces. These forces are generally either a direct result of microtubule polymerization/depolymerization or generated by motor proteins that move processively along microtubules. In this review, we summarize recent efforts to quantify and model force generation by microtubules in the context of microtubule function. WIREs Nanomed Nanobiotechnol 2017, 9:e1428. doi: 10.1002/wnan.1428 For further resources related to this article, please visit the WIREs website.

Downregulation of importin-9 protects MCF-7 cells against apoptosis induced by the combination of garlic-derived alliin and paclitaxel

Numerous studies on the biological mechanism of breast cancer have identified a number of potential therapeutic molecular targets. In this context, one type of potential candidates appears to be agents that target the actin cytoskeleton of cancer cells or regulate actin cytoskeleton dynamics. The aim of the present study was to study the impact of altered actin transport between the cytoplasm and nucleus by the downregulation of importin-9 (IPO9) in breast adenocarcinoma MCF-7 cells exposed to an apoptosis-inducing combination of garlic-derived S-allyl-L-cysteine sulfoxide (alliin) and paclitaxel (PTX). The expression of IPO9 was downregulated by the transfection of non-aggressive breast cancer MCF-7 cells with siRNA against IPO9. The altered expression of IPO9 and cofilin-1 (CFL1) was examined using western blotting. Moreover, the effect of the downregulation of IPO9 on cell death induced by the combination of PTX and alliin was also investigated. The alterations of IPO9 and CFL1 levels were also related with F-actin organizational changes and F-actin fluorescence intensity in the nuclear/perinuclear area of the cells. The results presented here indicate that alliin and PTX act synergistically to promote and potentiate apoptosis in MCF-7 cells. Furthermore, using RNA interference technique, we showed that downregulation of IPO9 expression was correlated with a significant reduction in the apoptotic cell population as well as with a decrease in F-actin content in whole cells, and in the cortical and nuclear/perinuclear areas of the cells. Simultaneously, the downregulation of IPO9 was also accompanied by the increased post-translational expression of CFL1. Furthermore, the data obtained in the present study allow us to conclude that CFL1 itself does not translocate actin into the cell nucleus but this transport requires the functional expression of IPO9.