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Background Triple negative breast cancer (TNBC) is an aggressive disease characterized by high risk of relapse and development of resistance to different chemotherapy agents. Several targeted therapies have been investigated in TNBC with modest results in clinical trials. Among these, PI3K/AKT inhibitors have been evaluated in addition to standard therapies, yielding conflicting results and making attempts on elucidating inherent mechanisms of resistance of great interest. Increasing evidences suggest that PI3K/AKT inhibitors can induce autophagy in different cancers. Autophagy represents a supposed mechanism of drug-resistance in aggressive tumors, like TNBC. We, therefore, investigated if two PI3K/AKT inhibitors, ipatasertib and taselisib, could induce autophagy in breast cancer models, and whether chloroquine (CQ), a well known autophagy inhibitor, could potentiate ipatasertib and taselisib anti-cancer effect in combination with conventional chemotherapy. Methods The induction of autophagy after ipatasertib and taselisib treatment was evaluated in MDAMB231, MDAM468, MCF7, SKBR3 and MDAB361 breast cancer cell lines by assaying LC3-I conversion to LC3-II through immunoblotting and immunofluorescence. Other autophagy-markers as p62/SQSTM1 and ATG5 were evaluated by immunoblotting. Synergistic antiproliferative effect of double and triple combinations of ipatasertib/taselisib plus CQ and/or paclitaxel were evaluated by SRB assay and clonogenic assay. Anti-apoptotic effect of double combination of ipatasertib/taselisib plus CQ was evaluated by increased cleaved-PARP by immunoblot and by Annexin V- flow cytometric analysis. In vivo experiments were performed on xenograft model of MDAMB231 in NOD/SCID mice. Results Our results suggested that ipatasertib and taselisib induce increased autophagy signaling in different breast cancer models. This effect was particularly evident in PI3K/AKT resistant TNBC cells, where the inhibition of autophagy by CQ potentiates the therapeutic effect of PI3K/AKT inhibitors in vitro and in vivo TNBC models, synergizing with taxane-based chemotherapy. Conclusion These data suggest that inhibition of authophagy with CQ could overcome mechanism of drug resistance to PI3K/AKT inhibitors plus paclitaxel in TNBC making the evaluation of such combinations in clinical trials warranted.

Early in the COVID-19 pandemic, it emerged that the risk of severe outcomes was greater in patients with co-morbidities, including cancer. The huge effort undertaken to fight the pandemic, affects the management of cancer care, influencing their outcome. Despite the high fatality rate of COVID-19 disease in cancer patients, rare cases of temporary or prolonged clinical remission from cancers after SARS-CoV-2 infection have been reported. We have reviewed sixteen case reports of COVID-19 disease with spontaneous cancer reduction of progression. Fourteen cases of remission following viral infections and two after anti-SARS-CoV-2 vaccination. The immune response to COVID-19, may be implicated in both tumor regression, and progression. Specifically, we discuss potential mechanisms which include oncolytic and priming hypotheses, that may have contributed to the cancer regression in these cases and could be useful for future options in cancer treatment.

Background Molecular markers for prostate cancer (PCa) are required to improve the early definition of patient outcomes. Atypically large extracellular vesicles (EVs), referred as “Large Oncosomes” (LO), have been identified in highly migratory and invasive PCa cells. We recently developed and characterized the DU145R80 subline, selected from parental DU145 cells as resistant to inhibitors of mevalonate pathway. DU145R80 showed different proteomic profile compared to parental DU145 cells, along with altered cytoskeleton dynamics and a more aggressive phenotype. Methods Immunofluorescence staining and western blotting were used to identify blebbing and EVs protein cargo. EVs, purified by gradient ultra-centrifugations, were analyzed by tunable resistive pulse sensing and multi-parametric flow cytometry approach coupled with high-resolution imaging technologies. LO functional effects were tested in vitro by adhesion and invasion assays and in vivo xenograft model in nude mice. Xenograft and patient tumor tissues were analyzed by immunohistochemistry. Results We found spontaneous blebbing and increased shedding of LO from DU145R80 compared to DU145 cells. LO from DU145R80, compared to those from DU145, carried increased amounts of key-molecules involved in PCa progression including integrin alpha V (αV-integrin). By incubating DU145 cells with DU145R80-derived LO we demonstrated that αV-integrin on LO surface was functionally involved in the increased adhesion and invasion of recipient cells, via AKT. Indeed either the pre-incubation of LO with an αV-integrin blocking antibody, or a specific AKT inhibition in recipient cells are able to revert the LO-induced functional effects. Moreover, DU145R80-derived LO also increased DU145 tumor engraftment in a mice model. Finally, we identified αV-integrin positive LO-like structures in tumor xenografts as well as in PCa patient tissues. Increased αV-integrin tumor expression correlated with high Gleason score and lymph node status. Conclusions Overall, this study is the first to demonstrate the critical role of αV-integrin positive LO in PCa aggressive features, adding new insights in biological function of these large EVs and suggesting their potential use as PCa prognostic markers.

Background Pancreatic ductal adenocarcinoma (PDAC) represents an unmet clinical need due to the very poor prognosis and the lack of effective therapy. Here we investigated the potential of domatinostat (4SC-202), a new class I histone deacetylase (HDAC) inhibitor, currently in clinical development, to sensitize PDAC to first line standard gemcitabine (G)/taxol (T) doublet chemotherapy treatment. Methods Synergistic anti-tumor effect of the combined treatment was assessed in PANC1, ASPC1 and PANC28 PDAC cell lines in vitro as well as on tumor spheroids and microtissues, by evaluating combination index (CI), apoptosis, clonogenic capability. The data were confirmed in vivo xenograft models of PANC28 and PANC1 cells in athymic mice. Cancer stem cells (CSC) targeting was studied by mRNA and protein expression of CSC markers, by limiting dilution assay, and by flow cytometric and immunofluorescent evaluation of CSC mitochondrial and cellular oxidative stress. Mechanistic role of forkhead box M1 (FOXM1) and downstream targets was evaluated in FOXM1-overexpressing PDAC cells. Results We showed that domatinostat sensitized in vitro and in vivo models of PDAC to chemotherapeutics commonly used in PDAC patients management and particularly to GT doublet, by targeting CSC compartment through the induction of mitochondrial and cellular oxidative stress. Mechanistically, we showed that domatinostat hampers the expression and function of FOXM1, a transcription factor playing a crucial role in stemness, oxidative stress modulation and DNA repair. Domatinostat reduced FOXM1 protein levels by downregulating mRNA expression and inducing proteasome-mediated protein degradation thus preventing nuclear translocation correlated with a reduction of FOXM1 target genes. Furthermore, by overexpressing FOXM1 in PDAC cells we significantly reduced domatinostat-inducing oxidative mitochondrial and cellular stress and abolished GT sensitization, both in adherent and spheroid cells, confirming FOXM1 crucial role in the mechanisms described. Finally, we found a correlation of FOXM1 expression with poor progression free survival in PDAC chemotherapy-treated patients. Conclusions Overall, we suggest a novel therapeutic strategy based on domatinostat to improve efficacy and to overcome resistance of commonly used chemotherapeutics in PDAC that warrant further clinical evaluation.

Background Despite the introduction of several novel therapeutic approaches that improved survival, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease. Herein we report the synergistic antitumor interaction between two well-known drugs used for years in clinical practice, the antiepileptic agent with histone deacetylase inhibitory activity valproic acid and the cholesterol lowering agent simvastatin, in mCRPC models. Methods Synergistic anti-tumor effect was assessed on PC3, 22Rv1, DU145, DU145R80, LNCaP prostate cancer cell lines and EPN normal prostate epithelial cells, by calculating combination index (CI), caspase 3/7 activation and colony formation assays as well as on tumor spheroids and microtissues scored with luminescence 3D-cell viability assay. Cancer stem cells (CSC) compartment was studied evaluating specific markers by RT-PCR, western blotting and flow cytometry as well as by limiting dilution assay. Cholesterol content was evaluated by 1 H-NMR. Overexpression of wild-type YAP and constitutively active YAP5SA were obtained by lipofectamine-based transfection and evaluated by immunofluorescence, western blotting and RT-PCR. 22Rv1 R_39 docetaxel resistant cells were selected by stepwise exposure to increasing drug concentrations. In vivo experiments were performed on xenograft models of DU145R80, 22Rv1 parental and docetaxel resistant cells, in athymic mice. Results We demonstrated the capacity of the combined approach to target CSC compartment by a novel molecular mechanism based on the inhibition of YAP oncogene via concurrent modulation of mevalonate pathway and AMPK. Because both CSCs and YAP activation have been associated with chemo-resistance, we tested if the combined approach can potentiate docetaxel, a standard of care in mCRCP treatment. Indeed, we demonstrated, both in vitro and in vivo models, the ability of valproic acid/simvastatin combination to sensitize mCRPC cells to docetaxel and to revert docetaxel-resistance, by mevalonate pathway/YAP axis modulation. Conclusion Overall, mCRPC progression and therapeutic resistance driven by CSCs via YAP, can be tackled by the combined repurposing of two generic and safe drugs, an approach that warrants further clinical development in this disease.

Background Metastatic pancreatic ductal adenocarcinoma (mPDAC) patients have very poor prognosis highlighting the urgent need of novel treatments. In this regard, repurposing non-oncology already-approved drugs might be an attractive strategy to offer more-effective treatment easily tested in clinical trials. Accumulating evidence suggests that epigenetic deregulation is a hallmark of cancer contributing to treatment resistance in several solid tumors, including PDAC. Histone deacetylase inhibitors (HDACi) are epigenetic drugs we have investigated preclinically and clinically as anticancer agents. Valproic acid (VPA) is a generic low-cost anticonvulsant and mood stabilizer with HDAC inhibitory activity, and anticancer properties also demonstrated in PDAC models. Statins use was reported to be associated with lower mortality risk in patients with pancreatic cancer and statins have been shown to have a direct antitumor effect when used alone or in combination therapy. We recently showed capability of VPA/Simvastatin (SIM) combination to potentiate the antitumor activity of gemcitabine/nab-paclitaxel in vitro and in vivo PDAC preclinical models. Methods/Design VESPA is a patient-centric open label randomized multicenter phase-II investigator-initiated trial, evaluating the feasibility, safety, and efficacy of VPA/SIM plus first line gemcitabine/nab-paclitaxel-based regimens (AG or PAXG) (experimental arm) versus chemotherapy alone (standard arm) in mPDAC patients. The study involves Italian and Spanish oncology centers and includes an initial 6-patients safety run-in-phase. A sample size of 240 patients (120 for each arm) was calculated under the hypothesis that the addition of VPA/SIM to gemcitabine and nab-paclitaxel-based regimens may extend progression free survival from 6 to 9 months in the experimental arm. Secondary endpoints are overall survival, response rate, disease control rate, duration of response, CA 19.9 reduction, toxicity, and quality of life. The study includes a patient engagement plan and complementary biomarkers studies on tumor and blood samples. Conclusions VESPA is the first trial evaluating efficacy and safety of two repurposed drugs in oncology such as VPA and SIM, in combination with standard chemotherapy, with the aim of improving mPDAC survival. The study is ongoing. Enrollment started in June 2023 and a total of 63 patients have been enrolled as of June 2024. Trial registration EudraCT number: 2022-004154-63; ClinicalTrials.gov identifier NCT05821556, posted 2023/04/20.

Background Despite advancements in therapeutic approaches, including taxane-based chemotherapy and androgen receptor-targeting agents, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable tumor, highlighting the need for 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 valproic acid (VPA), an antiepileptic agent with histone deacetylase inhibitory activity, with the lipid-lowering drug simvastatin (SIM). This combination sensitizes mCRPC cells to docetaxel treatment both in vitro and in vivo by targeting the cancer stem cell compartment via mevalonate pathway/YAP axis modulation. Methods Here, using a combined proteomic and metabolomic/lipidomic approach, we characterized tumor samples derived from 22Rv1 mCRPC cell-xenografted mice treated with or without VPA/SIM and performed an in-depth bioinformatics analysis. Results We confirmed the specific impact of VPA/SIM on the Hippo–YAP signaling pathway, which is functionally related to the modulation of cancer-related extracellular matrix biology and metabolic reprogramming, providing further insights into the molecular mechanism of the antitumor effects of VPA/SIM. Conclusions In this study, we present an in-depth exploration of the potential to repurpose two generic, safe drugs for mCRPC treatment, valproic acid (VPA) and simvastatin (SIM), which already show antitumor efficacy in combination, primarily affecting the cancer stem cell compartment via MVP/YAP axis modulation. Bioinformatics analysis of the LC‒MS/MS and 1 H‒NMR metabolomics/lipidomics results confirmed the specific impact of VPA/SIM on Hippo–YAP.

Background Osteosarcoma (OS) shows a multitude of genetic and chromosomal abnormalities together with large biological heterogeneity. These features limited the identification of novel drugs to treat patients with metastases and/or chemo-resistant tumors. The purpose of this study was to create additional resources for drug screening by generating patient-derived xenograft (PDXs) and PDX-derived cell lines that reflect the spectrum of OS heterogeneity. Methods PDXs were derived from OS collected at diagnosis, surgical resections, or metastases. PDX-derived cell lines were also established. Targeted DNA sequencing and digital PCR were applied to identify major genetic alterations. High-throughput drug screening by using a library of 2880-FDA approved compounds and conventional MTT assays were performed to identify the most effective drugs against in vitro and in vivo growth of chemo-resistant OS. Results Targeted DNA sequencing demonstrated alterations in the most commonly amplified oncogenes, such as MYC , CCNE1 , DDR2 , CDK4 , MDM2 , and AURKA. Recurrent deletions and SNVs were found in TP53 , CDKN2A , RB1 , PTEN , and VHL. Copy number variant (CNV) alterations in PDXs, PDX-derived cell lines and xenografts developed from cell lines (CDX) correlated very well with those observed in the matched original human tumors. Drug screenings identified and repurposed five compounds with efficacy against chemoresistant OS. In this context, we prioritized ixabepilone as a drug capable of inducing tumor regression in mice. Conclusions We enriched the scientific community with additional, molecularly characterized OS models to be used for testing novel therapies and supported the inclusion of ixabepilone into treatment plans for chemoresistant OS.

Anthracyclines and human epidermal growth factor receptor 2 (HER-2) inhibitors are cornerstone therapies for breast cancer but are associated with significant cardiotoxicity. While sodium–glucose cotransporter 2 (SGLT2) inhibitors such as dapagliflozin have demonstrated cardio–renal protective effects during anthracycline treatment, their efficacy in preventing cardiotoxicity from sequential anthracycline and HER-2 blockade remains poorly understood. This study investigates the cardioprotective role of dapagliflozin in a preclinical model of chemotherapy-induced cardiotoxicity. Female C57Bl/6 mice were divided into four groups and treated for 10 days as follows: (1) a normal control group receiving saline (sham); (2) a model control group receiving doxorubicin (2.17 mg/kg/day for 5 days) followed by HER-2-blocking monoclonal antibody (2.25 mg/kg/day for 5 days); (3) a dapagliflozin-only group (10 mg/kg/day via oral gavage); and (4) a treatment group receiving the combination of doxorubicin, HER-2 inhibitor, and dapagliflozin. Cardiac function was assessed using echocardiography (VEVO 2100). Biomarkers of myocardial injury and inflammation (NLRP3, MyD88, CXCR4, H-FABP, troponin-T, and cytokines) were quantified via ELISA and immunohistochemistry. Circulating markers such as mitofusin-2, cardiac myosin light chain, malondialdehyde (MDA), and 4-hydroxy-2-nonenal (4-HNE) were also measured. Dapagliflozin significantly preserved the ejection fraction and reduced both radial and longitudinal strain impairment in mice treated with the doxorubicin–HER-2 inhibitor combination (p < 0.001). Levels of myocardial NLRP3, MyD88, CXCR4, H-FABP, interleukin-1β, and troponin-T were significantly lower in the dapagliflozin-treated group compared to the chemotherapy-only group. Serum markers of oxidative stress and cardiac injury, including mitofusin-2, MDA, 4-HNE, BNP, and high-sensitivity C-reactive protein (hs-CRP), were also reduced by dapagliflozin treatment. Our findings demonstrate that dapagliflozin effectively mitigates early cardiac dysfunction and injury in a preclinical model of sequential doxorubicin and HER-2 inhibitor therapy.

Despite advances in systemic therapeutic approaches, metastatic colorectal cancer (mCRC) patients harboring BRAF or RAS mutations have poor outcomes. Cancer stem cells (CSCs) play central roles in drug resistance and CRC recurrence. Therefore, targeting the epigenetic mechanisms that sustain CSC properties is a promising therapeutic approach. In this study, we report the efficacy of a treatment strategy with the potential to overcome chemotherapy resistance that involves administering the well-known antiepileptic drug and epigenetic agent valproic acid (VPA) and the standard chemotherapy regimen of oxaliplatin/fluoropyrimidine to wild-type CSCs and CSCs with BRAF and RAS mutations in enriched primary spheroid cultures. Notably, we demonstrated that VPA plus chemotherapy was more effective than other epigenetic drug-chemotherapy combinations by inhibiting cell proliferation and clonogenic growth and by inducing apoptosis and DNA damage. Mechanistically, proteomic analysis demonstrated that VPA induced CSC differentiation through the critical target of VPA, β-Catenin. Indeed, VPA promoted the proteasome-dependent degradation of β-Catenin by enhancing its binding to the E2 ubiquitin-conjugating enzyme UBE2a, leading to marked reductions in nuclear and cytoplasmic β-Catenin levels and subsequently decreasing β-Catenin/TCF-LEF target promoter activation. These effects were confirmed in three in vivo CRC xenograft models, including a syngeneic CT26 immunocompetent mouse model, where VPA combined with oxaliplatin/capecitabine chemotherapy and anti-VEGF therapy, a standard first-line treatment for mCRC, significantly suppressed tumor growth and prolonged survival with minimal toxicity. Proteomic analysis of tumor tissues from in vivo CRC models confirmed the VPA-mediated downregulation of CSC markers and β-Catenin.