Docetaxel Treatment Research Articles

Abstract 4617: Fisetin, a multi-kinase inhibitor enhances chemotherapeutic sensitivity in head and neck cancer

Abstract Background: The limitations of chemotherapeutic applications are often imposed by dose-related toxicity and the emergence of therapeutic resistance. Fisetin, a naturally occurring flavonoid, has demonstrated anticancer properties in various cancer types. Despite its proven effectiveness against cancer, the molecular target of fisetin remains unknown. Methods: Our study focused on understanding how fisetin and chemotherapy work together to inhibit the growth and survival of human HNC. We conducted in silico, in vitro and in vivo investigations. We employed target prediction, kinase profiling, transcriptome analysis and tumor xenograft to identify the chemosensitivity efficacy and mechanism of fisetin. Results: In-silico target prediction suggested that fisetin might target multiple kinases. Based on this lead, we have screened fisetin for different kinase inhibition activities and found that it inhibits multiple CDKs including CDK1, 2, 4, 5 and 6 at nanomolar concentration. To test its cellular activity, we have selected the head and neck cancer (HNC) model and found that fisetin treatment strongly inhibited cell proliferation and arrested the HNC cells in G1 phase followed by apoptotic cell death. In tumor xenograft experiment, we found that oral fisetin treatment inhibited the FaDu and SAS tumor growth in the athymic mouse model. Transcriptome analysis on FaDu and SAS cell lines indicated that fisetin treatment significantly modulates pathways associated with cell cycle progression and regulation. These pathways include cellular assembly, DNA replication, cell death, and cell morphology. Pretreatment of HNC cells with fisetin improved the effectiveness of chemotherapy drugs including cisplatin, 5-fluorouracil, and docetaxel. Consistent with this, fisetin pre-treated cells showed elevated levels of cellular and mitochondrial ROS followed by the activation of caspases and apoptosis induction when compared with that in control cells after cisplatin, 5-FU, or docetaxel treatment. Conclusion: These results imply that fisetin has the potential to be utilized as a multi-kinase inhibitor in cancer cells. The study revealed that fisetin has a strong potential for increasing the sensitivity of cancer cells to chemotherapy. Citation Format: Dhanir Tailor, Deepali Mishra, Sanjay V. Malhotra, Rana P. Singh. Fisetin, a multi-kinase inhibitor enhances chemotherapeutic sensitivity in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4617.

Abstract 4508: Defining PIM kinase protein regulation and PROTAC for pre-clinical testing

Abstract The PIM kinase family are serine/threonine kinases known to be overexpressed in castration-resistant prostate cancer (CRPC). PIM1, an isoform of PIM, is known to regulate cell survival, migration, and proliferation. Uniquely, PIM kinases are constitutively active due to the lack of a regulatory domain. Therefore, PIM protein levels are reflected in PIM activity and are regulated by protein degradation and synthesis. PIM inhibitors have been developed, targeting the PIM kinase activity and inhibiting phosphorylation of downstream targets, but have had limited efficacy. Our lab and others demonstrate that PIM inhibitor treatment increases total PIM protein levels, suggesting that PIM kinases control protein stability via autophosphorylation. To elucidate the mechanism of autophosphorylation dependent regulation of PIM1, we used phospho-proteomics to identify potential autophosphorylation sites on PIM1. We have identified overexpression of deubiquitinase USP28 inhibiting degradation of PIM1, leading to the investigation of the role of F-box protein Fbw7 in regulating PIM1. Dominant-negative expression of Fbw7 results in increased PIM1 total protein. Additionally, coimmunoprecipitation of Fbw7 knockdown cells resulted in decreased PM1 ubiquitination compared to control. Therefore, we have identified Fbw7 as a putative E3 ligase responsible for PIM1 degradation. To address the limited efficacy of PIM inhibitors, we have developed the first PIM-PROTAC (PIMTAC) with our collaborators. Proteolysis targeting chimera (PROTAC) is a promising approach to eliminating the pro-tumorigenic effects of PIM. The PIMTAC selectively targets PIM kinases for degradation and we have demonstrated in vitro efficacy. PIMTAC successfully maintains degradation of all isoforms of PIM for over 72 hours. In vitro assessment of anti-tumor efficacy demonstrated increased apoptotic death with PIMTAC alone compared to PIM inhibitor or docetaxel. Furthermore, dual treatment of PIMTAC and docetaxel had more apoptotic death compared to PIM inhibitor with docetaxel. We aim to develop the PIMTAC for pre-clinical testing. Citation Format: Hope Liou, John Brognard, Rolf Swenson, Pedro Torres-Ayuso, Noel Warfel. Defining PIM kinase protein regulation and PROTAC for pre-clinical testing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4508.

Abstract 635: Osteoclasts mediate chemotherapy resistance in a fully humanized microphysiologic system of prostate cancer bone metastases

Abstract Bone metastases (BM) are the most common sites of metastases in prostate cancer, occurring in ~85% of patients. Overall survival of men with castrate resistant prostate cancer with BM is less than 24 months. Docetaxel is the most commonly used therapy for patients with prostate cancer, but the response rate is only 30-40% and median duration of response is less than 9 months. Non-tumor components of the Tumor Microenvironment (TME) have been proposed to mediate treatment resistance, but few pre-clinical models capture the complex physiology of the human bone TME. We report the development of a bone TME using a humanized microphysiologic system to address this need. The LumeNEXT platform is a microphysiologic system that allows the 3-dimensional (3D) reconstitution and integrated analysis of a bone-specific TME microenvironment with functional microvasculature that traverses the chip and can be used to mimic drug delivery in patients. Primary human osteoclasts (OC) were differentiated from patient peripheral blood monocytes. LNCaP prostate cancer spheroids were grown in hanging droplets. We performed co-culture of OCs with 3D LNCaP spheroids and evaluated the efficacy of docetaxel-induced tumor cell killing in the presence of bone cells. OCs and PC spheroids were seeded into LumeNEXT devices in a collagen-based matrix and treated with 20 nM Docetaxel or DMSO vehicle for 48 hours. Docetaxel response was assessed using confocal microscopy for single spheroid diameter and cytotoxicity was measured using fluorescent cell death markers. Docetaxel-mediated killing of tumor spheroids was found to be significantly attenuated in the presence of OCs. In LNCaP only conditions, average Docetaxel-mediated cell death was 68.82%, compared to 53.86% in the LNCaP and OC co-culture condition (p<0.0001). Furthermore, Docetaxel treatment resulted in reduced tumor spheroid diameter compared to DMSO control when prostate cancer spheroids were cultured alone (p=0.0118). Additionally, the presence of OCs attenuated Docetaxel-induced morphological changes. Our data suggest that osteoclasts play a significant role in mediating chemotherapy response in prostate cancer. Future studies will examine transcriptional changes in prostate cancer cells that may be associated with Docetaxel resistance in the bone microenvironment and identify mechanisms of BM microenvironment-mediated drug resistance. Bioinformatic analysis of patient sequencing datasets is ongoing to identify osteoclast-associated signatures of treatment resistance. Citation Format: Adeline B. Ding, Erika Heninger, Shannon R. Reese, Cristina Sanchez-de-Diego, Ravi C. Yada, Nan Sethakorn, Sheena C. Kerr, Xavier T. Hazelberg, Marina N. Sharifi, David J. Beebe, Joshua M. Lang. Osteoclasts mediate chemotherapy resistance in a fully humanized microphysiologic system of prostate cancer bone metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 635.

Abstract 310: Cadherin-dependent modulation of chemosensitivity in oral tumor progression

Abstract The progression of healthy oral epithelia to an oral carcinoma often involves aberrant expression of a group of calcium-dependent transmembrane proteins called cadherins. Histological studies of human tumors have demonstrated increased expression of the epithelial-resident placental (P-cadherin) and ectopic expression of the mesenchymal neuronal (N-cadherin) cadherin in oral dysplasia. We hypothesized that these changes in cadherin expression during early oral tumor development could facilitate increases in survival signaling. We genetically modified dysplastic oral keratinocytes to overexpress P-cadherin or suppress endogenous expression of N-cadherin. P-cadherin overexpression and N-cadherin suppression independently elicited a 3-6-fold decrease in apoptosis levels in response to docetaxel treatment compared to similarly treated controls. We found that in untreated dysplastic cells, P- and N-cadherin expression had positive and negative correlations, respectively, with the activation of the survival-associated enzymes focal adhesion kinase (FAK), mitogen-activated protein kinase (MAPK), and AKT kinase. The total levels of nuclear factor kappa B (NFkb) were positively correlated with P-cadherin overexpression and reciprocally correlated with levels of N-cadherin. In docetaxel-treated dysplastic cells, we observed the reverse effect compared to untreated cells: the increased level of N-cadherin was positively correlated with FAK activity whereas FAK activity was suppressed by P-cadherin. P-cadherin expression in docetaxel-treated cells also increased activation of both MAPK and AKT, whereas alteration of N-cadherin levels had no effect. Because N-cadherin levels are known to increase in late-stage oral tumors, we extended these signaling studies to oral squamous carcinoma cells (OSCCs) expressing low or high levels of N-cadherin. In contrast to its suppression of survival pathways in docetaxel-treated dysplastic cells, in docetaxel-treated OSCCs, N-cadherin expression strongly enhanced phosphorylation of MAPK and AKT, and increased expression of NFkb. N-cadherin overexpression during this treatment also increased expression of the antiapoptotic proteins Mcl-1 and suppressed phosphorylation of the apoptotic regulator signal transducer and activator of transcription 3 (pSTAT3). Increase cadherin expression in all untreated cell lines increased expression of an inducer of epithelial to mesenchymal transition, the transmembrane protein mucin-1 (MUC1). N-cadherin overexpression also increased motility in both cell lines. Taken together, our data demonstrate antiapoptotic signaling directed by increased levels of P-cadherin in oral dysplasia and N-cadherin in OSCC, whereas increased levels of N-cadherin in dysplastic cells directed cellular signaling that were associated with a proapoptotic phenotype. Citation Format: Aaron Mody, Cassandra Decker, Kathryn R. Lawson. Cadherin-dependent modulation of chemosensitivity in oral tumor progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 310.

Abstract 1678: Docetaxel induces Rac1 and Cdc42 Rho GTPase activation in prostate cancer cells

Abstract Prostate cancer (PCa) is a major health burden that affects the quality of life of men worldwide. In the United States, PCa is the second leading cause of mortality among cancers that affect men. Treatment of advanced PCa aims to suppress androgen signaling and proliferation in cancer cells using anti-androgens and chemotherapy. However, the development of drug resistance is a major limitation to curing advanced prostate cancer and strategies to block mechanisms of therapy resistance would enhance treatment efficacy and potentially improve patient prognosis. Cdc42 and Rac1, members of the family of Rho GTPases, have been associated with the progression of different types of hormone-associated cancer, such as breast, ovary, and prostate, among others. The current study was designed to evaluate the role of Cdc42 and Rac1 in chemoresistant prostate cancer cells, including under castration-resistant and androgen-independent conditions. We did not observe significant differences in active (Rac-GTP) or total Rac1 levels in chemoresistant compared to parental PC3 or DU145 cells; similar findings were observed for Ccd42. Treatment of drug-naïve cells with a sublethal dose of docetaxel (10uM) induced gradual increases in Rac1-GTP up to 30 minutes in 22rv1, 60 minutes in LNCaP and DU145, and 24 hours in PC3 cells. Cdc42-GTP levels also increased with subacute docetaxel treatment up to 24 hours in 22rv1 and DU145. Chemoresistant 22rv1, PC3, and DU145 exhibited similar sensitivity to Rac1 and Ccd42 inhibitors including MB1-167, MBQ-168, EHop-097, with an IC50 of about 1uM for each compound and line. Ongoing studies are evaluating the role of these Rho-GTPases in 3-dimensional growth and survival. Citation Format: Andrea Paola López González, Jessica Colón González, María C. Santa María Fuentes, Surangani Dharmawardhane, Carlos J. Diaz Osterman. Docetaxel induces Rac1 and Cdc42 Rho GTPase activation in prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1678.

Abstract 7097: Integrated proteomics and metabolomics reveals new insight into the synergistic interaction of valproic acid plus simvastatin in prostate cancer xenograft model associated with down-modulation of YAP and TAZ signaling

Abstract Background: Despite advancements in therapeutic approaches, including taxane-based chemotherapy and androgen receptor targeting agents, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease, underlying the need of novel strategies that can target the complexities of this disease and bypass the development of drug-resistance mechanisms. We previously demonstrated the synergistic antitumor interaction of the antiepileptic with histone deacetylase inhibitory activity valproic acid (VPA), and the lipid-lowering drug simvastatin (SIM). This combination sensitizes mCRPC cells to docetaxel treatment and revert docetaxel-resistance, both in vitro and in vivo models, by targeting cancer stem cells compartment via mevalonate pathway/YAP axis modulation. Methods: Proteomic and metabolomic/lipidomic analysis on tumor samples were performed by LC-MS/MS-based shotgun proteomics and by 1H-NMR approach, respectively. Progenesis QI for proteomics v. 4.2 was used as label-free quantification platform. Functional annotation analysis were performed by using the DAVID v6.8 (Database for Annotation, Visualization and Integrated Discovery); g:Profiler WikiPathways databases; Reactome version 66; Ingenuity Pathway Analysis software. Partial least squares-discriminant analysis (PLS-DA) and Loading plot were performed by Metabo Analyst v5.0 tool. Results: Tumor samples derived from 22Rv1 mCRPC cells xenografted mice, treated or not with VPA/SIM combination were characterized by a combined proteomic and metabolomic/lipidomic approach. In deep bioinformatics analysis confirmed a specific impact of VPA/SIM on Hippo pathway, with a clear down regulation of YAP and its targets (CTGF, CycD1 ANKH1) in treated vs untreated tumors, functionally related with modulation of cancer-related extracellular matrix remodelling and metabolic reprogramming. Treatment also downregulated TEAD transcription factor mediating YAP-induced expression, along with the upregulation of 14-3-3, responsible for YAP cytoplasmic retention and degradation, paralleled by the up-regulation of YAP up-stream negative regulators such as LATS1 and AMPK. VPA/SIM also modulated intermediates of TCA, urea cycles and glycolysis and decreased cholesterol and fatty acids. Conclusion: In summary, this study provides further insights into the molecular mechanism of the VPA/SIM antitumor effect suggesting the potential of repurposing these two generic and safe drugs in combination with standard antitumor therapies also in other tumors besides mCRCP. Citation Format: Federica Iannelli, Rita Lombardi, Susan Costantini, Maria Serena Roca, Laura Addi, Francesca Bruzzese, Elena Di Gennaro, Alfredo Budillon, Biagio Pucci. Integrated proteomics and metabolomics reveals new insight into the synergistic interaction of valproic acid plus simvastatin in prostate cancer xenograft model associated with down-modulation of YAP and TAZ signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7097.

Abstract 7200: Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane therapy

Abstract Metastatic prostate cancer (PCa) is the leading cause of PCa-associated deaths and one of the leading causes of cancer mortality in men. Novel therapeutics, such as Prostate Specific Membrane Antigen (PSMA) ligand therapy, are emerging as effective treatment strategies for metastatic prostate cancer. However, most men succumb to Metastatic Castration Resistant Prostate Cancer (mCRPC) due to treatment resistance. MAGMAS, a 13.8 kDa mitochondrial protein, imports nuclear-encoded mitochondrial proteins into the mitochondrial matrix. MAGMAS is overexpressed in several aggressive tumors, such as breast cancer, glioblastoma, and prostate cancer. When overexpressed, MAGMAS plays a role as a cytoprotective protein by acting as a reactive oxygen species (ROS) scavenger that maintains sufficient ROS levels to promote cell proliferation but below the threshold levels that could lead to apoptosis. This study was designed to investigate the pro-survival and therapy-resistance functions of MAGMAS in treatment-resistant PCa cells. Predictively, we observed that the docetaxel (DTX)-resistant PC3-DR and DU145-DR PCa cell lines expressed significantly higher levels of MAGMAS compared to their drug-sensitive parental cell lines. We hypothesized that inhibiting Magmas reduces the aggressive properties of highly proliferative DTX-resistant metastatic PCa cell lines and re-sensitizes them to DTX. MAGMAS knockdown in DTX-resistant PC3 and DU145 cells in the presence of increasing DTX treatments enhanced sensitivity to DTX. Consistent with these results, pharmacological inhibition of MAGMAS with the novel BT#9 inhibitor in combination with increasing DTX concentrations also enhanced sensitivity to DTX in these cell lines. Additional studies using cell migration/invasion assays and tumor-sphere formation assays are underway to further establish MAGMAS as a potential therapeutic target to attenuate the aggressive properties of chemo-resistant PCa cells. Lastly, we will investigate the diagnostic potential of MAGMAS as a biomarker for advanced PCa and BT#9 as an imaging/therapeutic-specific agent for treatment-resistant tumors. Citation Format: Alfonso Duran, Kristen Whitley, Krystal Santiago, Adil Mohammed, Carlos Casiano, Bhaskar Das, Frankis Almaguel. Non-cytotoxic inhibition of nuclear encoded mitochondrial protein MAGMAS resensitize treatment resistant prostate cancer cells to taxane therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7200.

Neoadjuvant–adjuvant pertuzumab in HER2-positive early breast cancer: final analysis of the randomized phase III PEONY trial

The randomized, multicenter, double-blind, placebo-controlled, phase III PEONY trial (NCT02586025) demonstrated significantly improved total pathologic complete response (primary endpoint) with dual HER2 blockade in HER2-positive early/locally advanced breast cancer, as previously reported. Here, we present the final, long-term efficacy (secondary endpoints: event-free survival, disease-free survival, overall survival) and safety analysis (62.9 months’ median follow-up). Patients (female; n = 329; randomized 2:1) received neoadjuvant pertuzumab/placebo with trastuzumab and docetaxel, followed by adjuvant 5-fluorouracil, epirubicin, and cyclophosphamide, then pertuzumab/placebo with trastuzumab until disease recurrence or unacceptable toxicity, for up to 1 year. Five-year event-free survival estimates are 84.8% with pertuzumab and 73.7% with placebo (hazard ratio 0.53; 95% confidence interval 0.32–0.89); 5-year disease-free survival rates are 86.0% and 75.0%, respectively (hazard ratio 0.52; 95% confidence interval 0.30–0.88). Safety data are consistent with the known pertuzumab safety profile and generally comparable between arms, except for diarrhea. Limitations include the lack of ado-trastuzumab emtansine as an option for patients with residual disease and the descriptive nature of the secondary, long-term efficacy endpoints. PEONY confirms the positive benefit:risk ratio of neoadjuvant/adjuvant pertuzumab, trastuzumab, and docetaxel treatment in this patient population.

Impact of loperamide on the pharmacokinetics and tissue disposition of ritonavir-boosted oral docetaxel therapy; a preclinical assessment.

An oral docetaxel formulation boosted by the Cytochrome P450 (CYP) 3A inhibitor ritonavir, ModraDoc006/r, is currently under clinical investigation. Based on clinical data, the incidence of grade 1-2 diarrhea is increased with this oral docetaxel formulation compared to the conventional intravenous administration. Loperamide, a frequently used diarrhea inhibitor, could be added to the regimen as symptomatic treatment. However, loperamide is also a substrate of the CYP3A enzyme, which could result in competition between ritonavir and loperamide for this protein. Therefore, we were interested in the impact of coadministered loperamide on the pharmacokinetics of ritonavir-boosted oral docetaxel. We administered loperamide simultaneously or with an 8-hour delay to humanized CYP3A4 mice (with expression in liver and intestine) receiving oral ritonavir and docetaxel. Concentrations of docetaxel, ritonavir, loperamide and two of its active metabolites were measured. The plasma exposure (AUC and Cmax) of docetaxel was not altered during loperamide treatment, nor were the ritonavir plasma pharmacokinetics. However, the hepatic and intestinal dispositions of ritonavir were somewhat changed in the simultaneous, but not 8-hour loperamide treatment groups, possibly due to loperamide-induced delayed drug absorption. The pharmacokinetics of loperamide itself did not seem to be influenced by ritonavir. These results suggest that delayed loperamide administration can be added to ritonavir-boosted oral docetaxel treatment, without affecting the overall systemic exposure of docetaxel.

Manganese as a Possible Anticancer Enhancer in Docetaxel Treatment of Prostate Cancer Cells.

Treatment of castration-resistant prostate cancer with docetaxel (DOC) often leads to resistance. In this study, we investigated whether manganese (Mn) has the potential to enhance treatment when combined with DOC. PC3 cells were exposed to DOC or Mn individually and in combination and cell viability was analysed in a dose- and time-dependent manner. Cell toxicity, cell cycle analysis and apoptotic protein levels were determined after 48 h of treatment. Mn in combination with different concentrations of DOC significantly enhanced the inhibitory effect on cell viability. Although the lowest dose did not cause mitotic arrest, DOC increased toxicity, which was reduced when combined with Mn. Protein analyses indicated that Mn compensates for the suppression of death receptors when combined with a low concentration of DOC and induced non-apoptotic pathways when combined with a higher concentration. Combining DOC and Mn may allow for a reduction in DOC concentration with the potential to reduce side effects.

ATPase Copper Transporting Beta (ATP7B) Is a Novel Target for Improving the Therapeutic Efficacy of Docetaxel by Disulfiram/Copper in Human Prostate Cancer.

Docetaxel has been the standard first-line chemotherapy for lethal metastatic prostate cancer (mPCa) since 2004, but resistance to docetaxel treatment is common. The molecular mechanisms of docetaxel resistance remain largely unknown and could be amenable to interventions that mitigate resistance. We have recently discovered that several docetaxel-resistant mPCa cell lines exhibit lower uptake of cellular copper and uniquely express higher levels of a copper exporter protein ATP7B. Knockdown of ATP7B by silencing RNAs (siRNA) sensitized docetaxel-resistant mPCa cells to the growth-inhibitory and apoptotic effects of docetaxel. Importantly, deletions of ATP7B in human mPCa tissues predict significantly better survival of patients after their first chemotherapy than those with wild-type ATP7B (P = 0.0006). In addition, disulfiram (DSF), an FDA-approved drug for the treatment of alcohol dependence, in combination with copper, significantly enhanced the in vivo antitumor effects of docetaxel in a docetaxel-resistant xenograft tumor model. Our analyses also revealed that DSF and copper engaged with ATP7B to decrease protein levels of COMM domain-containing protein 1 (COMMD1), S-phase kinase-associated protein 2 (Skp2), and clusterin and markedly increase protein expression of cyclin-dependent kinase inhibitor 1 (p21/WAF1). Taken together, our results indicate a copper-dependent nutrient vulnerability through ATP7B exporter in docetaxel-resistant prostate cancer for improving the therapeutic efficacy of docetaxel.

Capivasertib combines with docetaxel to enhance anti-tumour activity through inhibition of AKT-mediated survival mechanisms in prostate cancer

Background/objectiveTo explore the anti-tumour activity of combining AKT inhibition and docetaxel in PTEN protein null and WT prostate tumours.MethodsMechanisms associated with docetaxel capivasertib treatment activity in prostate cancer were examined using a panel of in vivo tumour models and cell lines.ResultsCombining docetaxel and capivasertib had increased activity in PTEN null and WT prostate tumour models in vivo. In vitro short-term docetaxel treatment caused cell cycle arrest in the majority of cells. However, a sub-population of docetaxel-persister cells did not undergo G2/M arrest but upregulated phosphorylation of PI3K/AKT pathway effectors GSK3β, p70S6K, 4E-BP1, but to a lesser extent AKT. In vivo acute docetaxel treatment induced p70S6K and 4E-BP1 phosphorylation. Treating PTEN null and WT docetaxel-persister cells with capivasertib reduced PI3K/AKT pathway activation and cell cycle progression. In vitro and in vivo it reduced proliferation and increased apoptosis or DNA damage though effects were more marked in PTEN null cells. Docetaxel-persister cells were partly reliant on GSK3β as a GSK3β inhibitor AZD2858 reversed capivasertib-induced apoptosis and DNA damage.ConclusionCapivasertib can enhance anti-tumour effects of docetaxel by targeting residual docetaxel-persister cells, independent of PTEN status, to induce apoptosis and DNA damage in part through GSK3β.

Anticancer Effect by Combined Treatment of Artemisia annua L. Polyphenols and Docetaxel in DU145 Prostate Cancer Cells and HCT116 Colorectal Cancer Cells.

Docetaxel (DTX), a semi-synthetic analogue of paclitaxel (taxol), is known to exert potent anticancer activity in various cancer cells by suppressing normal microtubule dynamics. In this study, we examined how the anticancer effect of DTX is regulated by polyphenols extracted from Korean Artemisia annua L. (pKAL) in DU145 prostate cancer cells (mutant p53) and HCT116 colorectal cancer cells (wild-type p53). Here, we show that the anticancer effect of DTX was enhanced more significantly by pKAL in HCT116 cells than in DU145 cells via phase-contrast microscopy, CCK-8 assay, Western blot, and flow cytometric analysis of annexin V/propidium iodide-stained cells. Notably, mutant p53 was slightly downregulated by single treatment of pKAL or DTX in DU145 cells, whereas wild-type p53 was significantly upregulated by pKAL or DTX in HCT116 cells. Moreover, the enhanced anticancer effect of DTX by pKAL in HCT116 cells was significantly associated with the suppression of DTX-induced p53 upregulation, increase of DTX-induced phospho-p38, and decrease of DTX-regulated cyclin A, cyclin B1, AKT, caspase-8, PARP1, GM130, NF-κB p65, and LDHA, leading to the increased apoptotic cell death and plasma membrane permeability. Our results suggest that pKAL could effectively improve the anticancer effect of DTX-containing chemotherapy used to treat various cancers expressing wild-type p53.

MiR-622 Increases miR-30a Expression through Inhibition of Hypoxia-Inducible Factor 1α to Improve Metastasis and Chemoresistance in Human Invasive Breast Cancer Cells

Hypoxia-inducible factor 1α (HIF-1α) plays a pivotal role in the survival, metastasis, and response to treatment of solid tumors. Autophagy serves as a mechanism for tumor cells to eliminate misfolded proteins and damaged organelles, thus promoting invasiveness, metastasis, and resistance to treatment under hypoxic conditions. MicroRNA (miRNA) research underscores the significance of these non-coding molecules in regulating cancer-related protein synthesis across diverse contexts. However, there is limited reporting on miRNA-mediated gene expression studies, especially with respect to epithelial–mesenchymal transition (EMT) and autophagy in the context of hypoxic breast cancer. Our study reveals decreased levels of miRNA-622 (miR-622) and miRNA-30a (miR-30a) in invasive breast cancer cells compared to their non-invasive counterparts. Inducing miR-622 suppresses HIF-1α protein expression, subsequently activating miR-30a transcription. This cascade results in reduced invasiveness and migration of breast cancer cells by inhibiting EMT markers, such as Snail, Slug, and vimentin. Furthermore, miR-30a negatively regulates beclin 1, ATG5, and LC3-II and inhibits Akt protein phosphorylation. Consequently, this improves the sensitivity of invasive MDA-MB-231 cells to docetaxel treatment. In conclusion, our study highlights the therapeutic potential of inducing miR-622 to promote miR-30a expression and thus disrupt HIF-1α-associated EMT and autophagy pathways. This innovative strategy presents a promising approach to the treatment of aggressive breast cancer.

CONTACT-02: Phase 3 study of cabozantinib (C) plus atezolizumab (A) vs second novel hormonal therapy (NHT) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC).

18 Background: Pts who have progressed on a prior NHT and have mCRPC with extrapelvic nodal or visceral metastasis have a poor prognosis with limited, broadly available treatment options beyond chemotherapy. C promotes an immune-permissive tumor environment and may enhance response to immune checkpoint inhibitors (ICIs). Methods: Pts randomized 1:1 to C+A (C [40 mg PO QD] + A [1200 mg IV Q3W]) or control (ctrl) (abiraterone [1000 mg PO QD] + prednisone [5 mg PO BID] or enzalutamide [160 mg PO QD]) were stratified by liver metastasis (yes/no), prior docetaxel for mCSPC (yes/no), and prior NHT for mCSPC/M0CRPC/mCRPC. Key eligibility criteria: mCRPC with disease progression on one prior NHT, measurable extrapelvic nodal or visceral disease, ECOG PS ≤1, ongoing androgen deprivation therapy. Docetaxel was allowed for mCSPC. Dual primary endpoints are radiographic PFS by blinded independent radiology committee (BIRC) per RECIST 1.1 in the first 400 randomized pts (PITT) and OS in all randomized pts (ITT). Secondary endpoint is ORR by RECIST 1.1 per BIRC. Results: At the data cutoff (Feb 28, 2023), 507 pts (ITT) were randomized to receive C+A (n=253) or ctrl (n=254). Baseline and clinical characteristics were balanced between C+A and ctrl arms: 25% and 26% had liver metastasis, 21% and 20% received docetaxel for mCSPC, and 72% and 74% received first NHT for mCRPC. Median follow-up was 12.0 mo for ITT and 14.3 mo for PITT populations. Median PFS was significantly longer with C+A vs ctrl (6.3 vs 4.2 mo; HR 0.65, 95% CI 0.50-0.84; P=0.0007) including in subgroups with liver metastasis (6.0 vs 2.1 mo; HR 0.47 [95% CI 0.30- 0.74]) or prior docetaxel treatment for mCSPC (8.8 vs 4.1 mo; HR 0.55 [0.32-0.96]). ORR was higher in C+A vs ctrl in pts with follow-up ≥6 mo in ITT (13.6% [23/169] vs 4.2% [7/165]). Median DOR was 9.7 mo for C+A vs not reached for ctrl, and time to response was 2.3 vs 4.6 mo. DCR was 72.8% (123/169) vs 54.5% (90/165). OS data are immature. Treatment-emergent adverse events (TEAE) occurred in 97% in C+A vs 87% in ctrl (grade 3/4 events, 48% vs 23%). Grade 5 TEAEs occurred in 9% vs 12% and no grade 5 treatment-related AEs occurred in either arm. TEAEs led to the discontinuation of all treatment components in 16% in C+A and 15% in ctrl. Conclusions: C+A significantly improved PFS vs second NHT in pts who had progressed on a prior NHT and have mCRPC with extrapelvic nodal or visceral disease, a population with high unmet medical need. These PFS benefits were particularly notable in pts with liver metastasis and those who previously received docetaxel for mCSPC. Toxicities reported with each treatment arm were manageable. CONTACT-02 is the only phase 3 study of an ICI-based regimen to show a significant and clinically meaningful improvement in PFS in prostate cancer with visceral metastasis. Follow-up for OS is ongoing. Clinical trial information: NCT04446117.

Serine/threonine kinase 36 induced epithelial-mesenchymal transition promotes docetaxel resistance in prostate cancer

To investigate the role and potential mechanism of serine/threonine kinase 36 (STK36) in docetaxel resistance-prostate cancer (PCa). The expression of STK36 in PCa and the correlation with clinicopathological characteristics of PCa patients were analyzed using the data from different databases and tissue microarrays. To investigate the role of STK36 on cell proliferation, invasion, and migration, STK36 was overexpressed and silenced in DU-145 and PC-3 cell lines. Cell counting kit-8 (CCK8) was used to test cell proliferation. Cell invasion and migration were detected by cell wound scratch assay and trans well, respectively. The expression profile of STK36, E-Cadherin, and Vimentin was analyzed by Western blot. Cell apoptosis was detected by the TUNEL assay. STK36 expression was upregulated in PCa tissue compared with adjacent benign PCa tissue; it was higher in patients with advanced stages compared with lower stages and was significantly correlated with decreased overall survival. Up-regulation of STK36 significantly promoted the proliferation, invasion, and migration of DU-145 and PC-3 cells and compensated for the suppression caused by docetaxel treatment in vitro. A striking apoptosis inhibition could be observed when dealing with docetaxel, although the apoptosis of DU-145 and PC-3 cells was not affected by the STK36 exclusive overexpression. Besides, E-Cadherin expression was restrained while the expression levels of vimentin were all enhanced. The knockdown of STK36 reversed the above process. STK36 up-regulation could accelerate the biological behavior and docetaxel resistance of PCa by epithelial-mesenchymal transition (EMT) activation. STK36 may be potentially used as a target in PCa resolvent with docetaxel.

IMpower210: A phase III study of second-line atezolizumab vs. docetaxel in East Asian patients with non-small cell lung cancer.

IMpower210 (NCT02813785) explored the efficacy and safety of single-agent atezolizumab vs. docetaxel as second-line treatment for advanced non-small cell lung cancer (NSCLC) in East Asian patients. Key eligibility criteria for this phase III, open-label, randomized study included age ≥18 years; histologically documented advanced NSCLC per the Union for International Cancer Control/American Joint Committee on Cancer staging system (7th edition); Eastern Cooperative Oncology Group performance status of 0 or 1; and disease progression following platinum-based chemotherapy for advanced or metastatic NSCLC. Patients were randomized 2:1 to receive either atezolizumab (1,200 mg) or docetaxel (75 mg/m2). The primary study endpoint was overall survival (OS) in the intention-to-treat (ITT) population with wild-type epidermal growth factor receptor expression (ITT EGFR-WT) and in the overall ITT population. Median OS in the ITT EGFR-WT population (n=467) was 12.3 [95% confidence interval (95% CI), 10.3-13.8] months in the atezolizumab arm (n=312) and 9.9 (95% CI, 7.8-13.9) months in the docetaxel arm [n=155; stratified hazard ratio (HR), 0.82; 95% CI, 0.66-1.03]. Median OS in the overall ITT population was 12.5 (95% CI, 10.8-13.8) months with atezolizumab treatment and 11.1 (95% CI, 8.4-14.2) months (n=377) with docetaxel treatment (n=188; stratified HR, 0.87; 95% CI, 0.71-1.08). Grade 3/4 treatment-related adverse events (TRAEs) occurred in 18.4% of patients in the atezolizumab arm and 50.0% of patients in the docetaxel arm. IMpower210 did not meet its primary efficacy endpoint of OS in the ITT EGFR-WT or overall ITT populations. Atezolizumab was comparatively more tolerable than docetaxel, with a lower incidence of grade 3/4 TRAEs.

Protocol for a phase II study to evaluate the efficacy and safety of nivolumab as a postoperative adjuvant therapy for patients with esophageal cancer treated with preoperative docetaxel, cisplatin plus 5-fluorouracil treatment (PENTAGON trial).

In Japan, preoperative adjuvant chemotherapy followed by surgical resection is the standard treatment for patients with locally advanced esophageal squamous cell carcinoma. However, the risk of recurrence after surgical resection remains high. Although a randomized controlled trial evaluating the efficacy of nivolumab, a fully human monoclonal anti-programmed death 1 antibody, as postoperative adjuvant therapy after neoadjuvant chemoradiotherapy and surgery established its superior efficacy as adjuvant therapy, the efficacy for patients who received preoperative adjuvant chemotherapy has not been demonstrated. This study aims to elucidate the efficacy and safety of nivolumab as postoperative adjuvant therapy for patients with esophageal squamous cell carcinoma after preoperative adjuvant chemotherapy with docetaxel and cisplatin plus 5-fluorouracil followed by surgical resection. This study is a multi-institutional, single-arm, Phase II trial. We plan to recruit 130 esophageal squamous cell carcinoma patients, who have undergone preoperative adjuvant chemotherapy with docetaxel and cisplatin plus 5-fluorouracil followed by surgical resection. If the patient did not have a pathological complete response, nivolumab is started as a postoperative adjuvant therapy within 4-16 weeks after surgery. The nivolumab dose is 480 mg/day every four weeks. Nivolumab is administered for up to 12 months. The primary endpoint is disease-free survival; the secondary endpoints are overall survival, distant metastasis-free survival, and incidence of adverse events. To our knowledge this study is the first trial establishing the efficacy of nivolumab as postoperative adjuvant therapy for patients with esophageal squamous cell carcinoma after preoperative adjuvant chemotherapy with docetaxel and cisplatin plus 5-fluorouracil followed by surgical resection. In Japan, preoperative adjuvant chemotherapy followed by surgery is a well-established standard treatment for resectable, locally advanced esophageal squamous cell carcinoma. Therefore, developing an effective postoperative adjuvant therapy has been essential for improving oncological outcomes.

Aba enhances the apoptotic effect of docetaxel in the multidrug-resistant DU145 prostate cancer cell line

This study aimed to induce drug resistance in DU145 prostate cancer cells by exposing them to docetaxel and mitoxantrone, and to examine the effects of combining docetaxel and abscisic acid (ABA). The IC50 values for docetaxel and mitoxantrone in non-resistant cells were 54.57 nM and 6.25 nM, respectively, rising to 808.53 nM and 50.07 nM after resistance had developed. RT-PCR analysis showed that treatment of resistant cells with 50.07 nM docetaxel and 500 ?M ABA (ABA) resulted in the following changes in gene expression: heat shock protein (HSP) 70 (0.63-fold), glucose-regulated protein 94 (GRP94) 0.33-fold, inositol-requiring transmembrane kinase endoribonuclease-1? (IRE1?) 1.62-fold, ER degradation-enhancing alpha-mannosidase-like 1 (EDEM1) 1.77-fold, X-box binding protein 1 (XBP1) 1.53-fold, p21 (2.53-fold), cellular tumor antigen p53 (p53) 2.49-fold, bcl-2-like protein 4 (Bax) 2.7-fold, and tumor necrosis factor (TNF-?) 6.35-fold. Tali? cytometry analysis showed a 47% increase in apoptotic/necrotic cells with the combined treatment of docetaxel and ABA, compared to a 26% increase with docetaxel alone. Fluorescent staining revealed that co-administration of docetaxel and ABA increases apoptosis in resistant DU145 cells compared to treatment with docetaxel alone. This study suggests that combining ABA with docetaxel could be effective in drug-resistant prostate cancer.

LDH-A Inhibitor as a Remedy to Potentiate the Anticancer Effect of Docetaxel in Prostate Cancer.

Increased LDH-A activity promotes tumor growth, migration, invasion, and metastasis. This study aimed to investigate the effects of the combination of LDH-A inhibitor and Docetaxel on apoptosis and epithelial-mesenchymal transition (EMT) in the murine prostate cancer (PCa) model. The prostate cancer murine model was developed subcutaneously in 50 male B57CL/6 mice using the Tramp-C2 prostate cancer cell line. From the tumor tissue samples, apoptosis analysis was performed using TUNEL staining, and EMT was investigated using western blot and qPCR. Hematoxylin-eosin staining (HE) and Periodic acid-Schiff staining were used to histopathologically examine liver and kidney tissues. Lactate levels revealed that the Warburg effect was reversed with the LDH-A inhibitor. Both serum and tumor tissue apoptosis increased, and tumor sizes reduced in PCa+LDH-A inhibitor + Docetaxel treatment groups (p<0.05). The combination of LDH-A inhibitor and Docetaxel inhibited EMT mechanism by causing a decrease in Snail, Slug, Twist, and HIF-1α expressions as well as a decrease in N-cadherin and an increase in E-cadherin levels. Reprogramming glucose metabolism with an LDH-A inhibitor can increase the effectiveness of Docetaxel on apoptosis and metastasis mechanisms in PCa.