Browsing by Author "Dragoj, Miodrag (56672957500)"

Background/Objectives: Non-small cell lung carcinoma (NSCLC) is characterized by its diverse molecular profiles and varying responses to treatment, highlighting the importance of precision medicine in optimizing therapeutic outcomes. A promising approach involves using patient-derived cellular models, which provide insights into the unique biology of individual tumors and their responsiveness to treatment. Methods: We established short-term primary cell cultures from thirteen patients with NSCLC of different subtypes and stages, including both cancer and stromal cells. To evaluate the ex vivo cytotoxicity and selectivity of eight chemotherapeutics and erlotinib, we employed an immunoassay, and the results were analyzed using an automated imaging system. Scoring of the obtained results was also performed. The ex vivo responses to cisplatin, etoposide, and paclitaxel were correlated with the patients’ responses to therapy. We used Kaplan–Meier analysis to assess progression-free survival (PFS) differences among patient groups. Results: NSCLC cells exhibited significant variability in their responses to drugs, with stromal cells demonstrating greater sensitivity. Tumors at stages I-III responded to multiple treatments, whereas stage IV cells showed considerable resistance. Erlotinib effectively reduced cancer cell growth at lower doses but plateaued at higher concentrations. The immunoassay indicated 67% sensitivity and 100% specificity in predicting patient responses to chemotherapy. Sensitivity to etoposide and paclitaxel correlated with progression-free survival (PFS). Conclusions: A personalized treatment strategy, such as our immunoassay based on the ex vivo responses of cancer patients’ cells, can guide treatment decisions and, in some cases, serve as surrogate biomarkers for tumor types that lack actionable biomarkers. © 2025 by the authors.

Background/Objectives: Non-small cell lung carcinoma (NSCLC) is characterized by its diverse molecular profiles and varying responses to treatment, highlighting the importance of precision medicine in optimizing therapeutic outcomes. A promising approach involves using patient-derived cellular models, which provide insights into the unique biology of individual tumors and their responsiveness to treatment. Methods: We established short-term primary cell cultures from thirteen patients with NSCLC of different subtypes and stages, including both cancer and stromal cells. To evaluate the ex vivo cytotoxicity and selectivity of eight chemotherapeutics and erlotinib, we employed an immunoassay, and the results were analyzed using an automated imaging system. Scoring of the obtained results was also performed. The ex vivo responses to cisplatin, etoposide, and paclitaxel were correlated with the patients’ responses to therapy. We used Kaplan–Meier analysis to assess progression-free survival (PFS) differences among patient groups. Results: NSCLC cells exhibited significant variability in their responses to drugs, with stromal cells demonstrating greater sensitivity. Tumors at stages I-III responded to multiple treatments, whereas stage IV cells showed considerable resistance. Erlotinib effectively reduced cancer cell growth at lower doses but plateaued at higher concentrations. The immunoassay indicated 67% sensitivity and 100% specificity in predicting patient responses to chemotherapy. Sensitivity to etoposide and paclitaxel correlated with progression-free survival (PFS). Conclusions: A personalized treatment strategy, such as our immunoassay based on the ex vivo responses of cancer patients’ cells, can guide treatment decisions and, in some cases, serve as surrogate biomarkers for tumor types that lack actionable biomarkers. © 2025 by the authors.

Purpose: Multidrug resistance (MDR) may develop due to a series of adaptive responses under a new stress conditions, such as chemotherapy. Novel strategies are urgently needed to fight MDR in cancer, and chemotherapeutics that are selective for MDR cancer cells offer a promising approach. Certain protoflavones were previously found to have potential in this regard. Methods: Cytotoxicity of six protoflavones was assessed in different P-glycoprotein overexpressing MDR cancer cell lines and in their non-MDR counterparts. The impacts of compound 5, 6-methylprotoflavone previously published and a new derivative, 6-bromoprotoflavone (compound 6), on the cell cycle distribution were evaluated, and 6 was also studied for its potential to regulate the intracellular antioxidative capacity. Results: Protoflavones showed a significant cytotoxicity against all cancer cell lines and selectivity toward MDR cancer cells adapted to conventional chemotherapeutics. Inverse sensitivity versus MDR selectivity pattern was observed. Treatment with H2O2 showed that MDR cancer cells are more vulnerable to oxidative stress. Compounds 5 and 6 significantly decreased the portion of MDR cells in the G1 phase. The levels of reactive oxygen and nitrogen species (ROS/RNS) between MDR and non-MDR cells significantly differed upon exposure to 6, accompanied by changes in the glutathione (GSH) levels and in the expression of manganese superoxide dismutase (MnSOD), glutathione-S-transferase π (GST π) and hypoxia-inducible factor-1α (HIF-1α). Conclusions: Our results suggest that MDR cancer cells can be more vulnerable to the pro-oxidative activity of protoflavones due to an impaired antioxidative defense that might arise during the adaptation processes provoked by chemotherapy. © Springer-Verlag Berlin Heidelberg 2015.

Purpose: Multidrug resistance (MDR) may develop due to a series of adaptive responses under a new stress conditions, such as chemotherapy. Novel strategies are urgently needed to fight MDR in cancer, and chemotherapeutics that are selective for MDR cancer cells offer a promising approach. Certain protoflavones were previously found to have potential in this regard. Methods: Cytotoxicity of six protoflavones was assessed in different P-glycoprotein overexpressing MDR cancer cell lines and in their non-MDR counterparts. The impacts of compound 5, 6-methylprotoflavone previously published and a new derivative, 6-bromoprotoflavone (compound 6), on the cell cycle distribution were evaluated, and 6 was also studied for its potential to regulate the intracellular antioxidative capacity. Results: Protoflavones showed a significant cytotoxicity against all cancer cell lines and selectivity toward MDR cancer cells adapted to conventional chemotherapeutics. Inverse sensitivity versus MDR selectivity pattern was observed. Treatment with H2O2 showed that MDR cancer cells are more vulnerable to oxidative stress. Compounds 5 and 6 significantly decreased the portion of MDR cells in the G1 phase. The levels of reactive oxygen and nitrogen species (ROS/RNS) between MDR and non-MDR cells significantly differed upon exposure to 6, accompanied by changes in the glutathione (GSH) levels and in the expression of manganese superoxide dismutase (MnSOD), glutathione-S-transferase π (GST π) and hypoxia-inducible factor-1α (HIF-1α). Conclusions: Our results suggest that MDR cancer cells can be more vulnerable to the pro-oxidative activity of protoflavones due to an impaired antioxidative defense that might arise during the adaptation processes provoked by chemotherapy. © Springer-Verlag Berlin Heidelberg 2015.

The impact of tyrosine kinase inhibitors (TKIs) on multidrug resistance (MDR) in non-small cell lung carcinoma (NSCLC) is a critical aspect of cancer therapy. While TKIs effectively target specific signaling pathways of cancer cells, they can also act as substrates for ABC transporters, potentially triggering MDR. The aim of our study was to evaluate the response of 17 patient-derived NSCLC cultures to 10 commonly prescribed TKIs and to correlate these responses with patient mutational profiles. Using an ex vivo immunofluorescence assay, we analyzed the expression of the MDR markers ABCB1, ABCC1, and ABCG2, and correlated these data with the genetic profiles of patients for a functional diagnostic approach. NSCLC cultures responded differently to TKIs, with erlotinib showing good efficacy regardless of mutation burden or EGFR status. However, the modulation of MDR mechanisms by erlotinib, such as increased ABCG2 expression, highlights the challenges associated with erlotinib treatment. Other TKIs showed limited efficacy, highlighting the variability of response in NSCLC. Genetic alterations in signaling pathways associated with drug resistance and sensitivity, including TP53 mutations, likely contributed to the variable responses to TKIs. The relationships between ABC transporter expression, gene alterations, and response to TKIs did not show consistent patterns. Our results suggest that in addition to mutational status, performing functional sensitivity screening is critical for identifying appropriate treatment strategies with TKIs. These results underscore the importance of considering drug sensitivity, off-target effects, MDR risks, and patient-specific genetic profiles when optimizing NSCLC treatment and highlight the potential for personalized approaches, especially in early stages. © 2024 by the authors.

The impact of tyrosine kinase inhibitors (TKIs) on multidrug resistance (MDR) in non-small cell lung carcinoma (NSCLC) is a critical aspect of cancer therapy. While TKIs effectively target specific signaling pathways of cancer cells, they can also act as substrates for ABC transporters, potentially triggering MDR. The aim of our study was to evaluate the response of 17 patient-derived NSCLC cultures to 10 commonly prescribed TKIs and to correlate these responses with patient mutational profiles. Using an ex vivo immunofluorescence assay, we analyzed the expression of the MDR markers ABCB1, ABCC1, and ABCG2, and correlated these data with the genetic profiles of patients for a functional diagnostic approach. NSCLC cultures responded differently to TKIs, with erlotinib showing good efficacy regardless of mutation burden or EGFR status. However, the modulation of MDR mechanisms by erlotinib, such as increased ABCG2 expression, highlights the challenges associated with erlotinib treatment. Other TKIs showed limited efficacy, highlighting the variability of response in NSCLC. Genetic alterations in signaling pathways associated with drug resistance and sensitivity, including TP53 mutations, likely contributed to the variable responses to TKIs. The relationships between ABC transporter expression, gene alterations, and response to TKIs did not show consistent patterns. Our results suggest that in addition to mutational status, performing functional sensitivity screening is critical for identifying appropriate treatment strategies with TKIs. These results underscore the importance of considering drug sensitivity, off-target effects, MDR risks, and patient-specific genetic profiles when optimizing NSCLC treatment and highlight the potential for personalized approaches, especially in early stages. © 2024 by the authors.

Purpose: Anaplastic thyroid carcinoma (ATC) is an aggressive, chemo-resistant malignancy. Chemo-resistance is often associated with changes in activity of the RAS/MAPK/ERK and PI3K/AKT/mTOR pathways and/or a high expression of ATP binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). To assess the therapeutic efficacy in ATC of a combination of the dual mTOR kinase inhibitor vistusertib (AZD2014) and paclitaxel (PTX), we generated a new cell line (Rho-) via the selection of human thyroid carcinoma 8505C cells that exhibit a low accumulation of rhodamine 123, which serves as a P-gp and BCRP substrate. Methods: Immunohistochemistry was used for P-gp and BCRP expression analyses in primary ATC patient samples. Spheroid formation and immunodeficient NSG mice were used for performing in vitro and in vivo tumorigenicity assays, respectively. MTT, flow-cytometry, fluorescent microscopy, cell death and proliferation assays, as well as migration, invasion and gelatin degradation assays, were used to assess the potential of AZD2014 to enhance the effects of PTX. ATC xenografts in SCID mice were used for evaluating in vivo treatment efficacies. Results: Rho- cells were found to be 10-fold more resistant to PTX than 8505C cells and, in addition, to be more tumorigenic. We also found that AZD2014 sensitized Rho- cells to PTX by inhibiting proliferation and by inducing autophagy. The combined use of AZD2014 and PTX efficiently inhibited in vitro ATC cell migration and invasion. Subsequent in vivo xenograft studies indicated that the AZD2014 and PTX combination effectively suppressed ATC tumor growth. Conclusions: Our data support results from recent phase I clinical trials using combinations of AZD2014 and PTX for the treatment of solid tumors. Such combinations may also be employed for the design of novel targeted ATC treatment strategies. © 2018, International Society for Cellular Oncology.

Purpose: Anaplastic thyroid carcinoma (ATC) is an aggressive, chemo-resistant malignancy. Chemo-resistance is often associated with changes in activity of the RAS/MAPK/ERK and PI3K/AKT/mTOR pathways and/or a high expression of ATP binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). To assess the therapeutic efficacy in ATC of a combination of the dual mTOR kinase inhibitor vistusertib (AZD2014) and paclitaxel (PTX), we generated a new cell line (Rho-) via the selection of human thyroid carcinoma 8505C cells that exhibit a low accumulation of rhodamine 123, which serves as a P-gp and BCRP substrate. Methods: Immunohistochemistry was used for P-gp and BCRP expression analyses in primary ATC patient samples. Spheroid formation and immunodeficient NSG mice were used for performing in vitro and in vivo tumorigenicity assays, respectively. MTT, flow-cytometry, fluorescent microscopy, cell death and proliferation assays, as well as migration, invasion and gelatin degradation assays, were used to assess the potential of AZD2014 to enhance the effects of PTX. ATC xenografts in SCID mice were used for evaluating in vivo treatment efficacies. Results: Rho- cells were found to be 10-fold more resistant to PTX than 8505C cells and, in addition, to be more tumorigenic. We also found that AZD2014 sensitized Rho- cells to PTX by inhibiting proliferation and by inducing autophagy. The combined use of AZD2014 and PTX efficiently inhibited in vitro ATC cell migration and invasion. Subsequent in vivo xenograft studies indicated that the AZD2014 and PTX combination effectively suppressed ATC tumor growth. Conclusions: Our data support results from recent phase I clinical trials using combinations of AZD2014 and PTX for the treatment of solid tumors. Such combinations may also be employed for the design of novel targeted ATC treatment strategies. © 2018, International Society for Cellular Oncology.