Molecular Actions of Enicostemma hyssopifolium Whole Plant Extract on HPV18-Infected Human Cervical Cancer (HeLa) Cells.

OBJECTIVE: Enicostemma hyssopifolium (E. hyssopifolium) contains several bioactive compounds with anti-cancer activities. This study was performed to investigate the molecular effects of E. hyssopifolium on HPV18-containing HeLa cells. METHODS: The methanol extract of E. hyssopifolium whole plant was tested for cytotoxicity by MTT assay. A lower and higher dose (80 and 160 µg/mL) to IC50 were analyzed for colonization inhibition (Clonogenic assay), cell cycle arrest (FACS analysis), and induction of apoptosis (AO/EtBr staining fluorescent microscopy and FACS analysis) and DNA fragmentation (comet assay). The HPV 18 E6 gene expression in treated cells was analyzed using RT-PCR and qPCR. RESULTS: A significant dose-dependent anti-proliferative activity (IC50 - 108.25±2 µg/mL) and inhibition of colony formation cell line were observed using both treatments. Treatment with 80 µg/mL of extract was found to result in a higher percent of cell cycle arrest at G0/G1 and G2M phases with more early apoptosis, while 160 µg/mL resulted in more cell cycle arrest at SUBG0 and S phases with late apoptosis for control. The comet assay also demonstrated a highly significant increase in DNA fragmentation after treatment with 160 µg/mL of extract (tail moments-19.536 ± 17.8), while 80 µg/mL of extract treatment showed non-significant tail moment (8.152 ± 13.0) compared to control (8.038 ± 12.0). The RT-PCR and qPCR results showed a significant reduction in the expression of the HPV18 E6 gene in HeLa cells treated with 160 µg/mL of extract, while 80 µg/mL did not show a significant reduction. CONCLUSION: The 160 µg/mL methanol extract of E. hyssopifolium demonstrated highly significant anti-cancer molecular effects in HeLa cells.

Bone Marrow Stroma Co-cultivation Model of Breast Cancer Dormancy.

Breast cancer cells metastasize to the bone marrow before a primary tumor is detected. Most micrometastases die in this hostile microenvironment, but some survive and enter a state of dormancy and chemoresistance due to their close interaction with cells in the bone marrow hematopoietic niche. Over many years, some of the cells reawaken and result in metastatic disease that cannot be cured. Analyzing the cellular and molecular interactions between cancer and bone marrow niche cells requires relevant models that can be manipulated and studied. Generation of bone marrow stroma cultures in vitro permits the formation of cellular monolayers upon which breast cancer cells can be co-cultivated and their behavior interrogated using a variety of techniques. This manuscript describes the basic techniques for generating bone marrow stromal monolayers, co-incubating cancer cells and determining the effects on cancer cell proliferation and molecular signaling.

Enhancing maturity in 3D kidney micro-tissues through clonogenic cell combinations and endothelial integration.

As an advance laboratory model, three-dimensional (3D) organoid culture has recently been recruited to study development, physiology and abnormality of kidney tissue. Micro-tissues derived from primary renal cells are composed of 3D epithelial structures representing the main characteristics of original tissue. In this research, we presented a simple method to isolate mouse renal clonogenic mesenchymal (MLCs) and epithelial-like cells (ELCs). Then we have done a full characterization of MLCs using flow cytometry for surface markers which showed that more than 93% of cells expressed these markers (Cd44, Cd73 and Cd105). Epithelial and stem/progenitor cell markers characterization also performed for ELC cells and upregulating of these markers observed while mesenchymal markers expression levels were not significantly increased in ELCs. Each of these cells were cultured either alone (ME) or in combination with human umbilical vein endothelial cells (HUVECs) (MEH; with an approximate ratio of 10:5:2) to generate more mature kidney structures. Analysis of 3D MEH renal micro-tissues (MEHRMs) indicated a significant increase in renal-specific gene expression including Aqp1 (proximal tubule), Cdh1 (distal tubule), Umod (loop of Henle), Wt1, Podxl and Nphs1 (podocyte markers), compared to those groups without endothelial cells, suggesting greater maturity of the former tissue. Furthermore, ex ovo transplantation showed greater maturation in the constructed 3D kidney.

Evaluation of BH3 mimetics as a combination therapy with irradiation in head and neck squamous cell carcinoma.

INTRODUCTION: Head and neck squamous cell carcinoma (HNSCC) is a common cancer with a five-year survival rate around 60%, indicating a need for new treatments. BH3 mimetics are small molecules that inhibit anti-apoptotic Bcl-2 family proteins, resulting in apoptosis induction. METHODS: We performed a high-throughput screen using a Myogel matrix to identify the synergy between irradiation and the novel BH3 mimetics A-1155463, A-1331852, and navitoclax in 12 HNSCC cell lines, normal (NOF) and cancer-associated fibroblasts (CAF), and dysplastic keratinocytes (ODA). Next, we examined synergy in an apoptosis assay, followed by a clonogenic assay and a Myogel spheroid on selected HNSCC cell lines. Finally, we applied zebrafish larvae xenograft to validate the effects of navitoclax and A-1331852. RESULTS: All three BH3 mimetics exhibited a strong synergy with irradiation in eight HNSCC cell lines and ODAs, but not in NOFs and CAFs. A-1155463 and A-1331852 induced apoptosis and reduced proliferation, and together with irradiation, significantly increased apoptosis and arrested proliferation. A-1331852 and navitoclax significantly decreased the clonogenicity compared with the control, and combination treatment led to a decreased clonogenicity compared with monotherapy or irradiation. However, unlike navitoclax or A-1155463, only A-1331852 significantly reduced cancer cell invasion. Furthermore, in spheroid and zebrafish, irradiation appeared ineffective and failed to significantly increase the drug effect. In the zebrafish, A-1331852 and navitoclax significantly reduced the tumor area and metastasis. CONCLUSIONS: Our findings encourage the further preclinical investigation of BH3 mimetics, particularly A-1331852, as a single agent or combined with irradiation as a treatment for HNSCC.

Molecular mechanisms behind the generation of pro-oncogenic HIV-1 matrix protein p17 variants.

HIV-1 matrix protein p17 variants (vp17s), characterized by amino acid insertions at the COOH-terminal region of the viral protein, have been recently identified and studied for their biological activity. Different from their wild-type counterpart (refp17), vp17s display a potent B cell growth and clonogenic activity. Recent data have highlighted the higher prevalence of vp17s in people living with HIV-1 (PLWH) with lymphoma compared with those without lymphoma, suggesting that vp17s may play a key role in lymphomagenesis. Molecular mechanisms involved in vp17 development are still unknown. Here we assessed the efficiency of HIV-1 Reverse Transcriptase (RT) in processing this genomic region and highlighted the existence of hot spots of mutation in Gag, at the end of the matrix protein and close to the matrix-capsid junction. This is possibly due to the presence of inverted repeats and palindromic sequences together with a high content of Adenine in the 322-342 nucleotide portion, which constrain HIV-1 RT to pause on the template. To define the recombinogenic properties of hot spots of mutation in the matrix gene, we developed plasmid vectors expressing Gag and a minimally modified Gag variant, and measured homologous recombination following cell co-nucleofection by next-generation sequencing. Data obtained allowed us to show that a wide range of recombination events occur in concomitance with the identified hot spots of mutation and that imperfect events may account for vp17s generation.

The Effect of 4-(Dimethylamino)phenyl-5-oxopyrrolidines on Breast and Pancreatic Cancer Cell Colony Formation, Migration, and Growth of Tumor Spheroids.

A series of hydrazones, azoles, and azines bearing a 4-dimethylaminophenyl-5-oxopyrrolidine scaffold was synthesized. Their cytotoxic effect against human pancreatic carcinoma Panc-1 and triple-negative breast cancer MDA-MB-231 cell lines was established by MTT assay. Pyrrolidinone derivatives 3c and 3d, with incorporated 5-chloro and 5-methylbenzimidazole fragments; hydrazone 5k bearing a 5-nitrothien-2-yl substitution; and hydrazone 5l with a naphth-1-yl fragment in the structure significantly decreased the viability of both cancer cell lines. Compounds 3c and 5k showed the highest selectivity, especially against the MDA-MB-231 cancer cell line. The EC50 values of the most active compound 5k against the MDA-MB231 cell line was 7.3 ± 0.4 µM, which were slightly higher against the Panc-1 cell line (10.2 ± 2.6 µM). Four selected pyrrolidone derivatives showed relatively high activity in a clonogenic assay. Compound 5k was the most active in both cell cultures, and it completely disturbed MDA-MB-231 cell colony growth at 1 and 2 µM and showed a strong effect on Panc-1 cell colony formation, especially at 2 µM. The compounds did not show an inhibitory effect on cell line migration by the 'wound-healing' assay. Compound 3d most efficiently inhibited the growth of Panc-1 spheroids and reduced cell viability in MDA-MB-231 spheroids. Considering these different activities in biological assays, the selected pyrrolidinone derivatives could be further tested to better understand the structure-activity relationship and their mechanism of action.

Combining a noble gas with radiotherapy: glutamate receptor antagonist xenon may act as a radiosensitizer in glioblastoma.

BACKGROUND: Ionotropic glutamate receptors α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) and N-methyl-D-aspartate receptor (NMDAR) modulate proliferation, invasion and radioresistance in glioblastoma (GB). Pharmacological targeting is difficult as many in vitro-effective agents are not suitable for in patient applications. We aimed to develop a method to test the well tolerated AMPAR- and NMDAR-antagonist xenon gas as a radiosensitizer in GB. METHODS: We designed a diffusion-based system to perform the colony formation assay (CFA), the radiobiological gold standard, under xenon exposure. Stable and reproducible gas atmosphere was validated with oxygen and carbon dioxide as tracer gases. After checking for AMPAR and NMDAR expression via immunofluorescence staining we performed the CFA with the glioblastoma cell lines U87 and U251 as well as the non-glioblastoma derived cell line HeLa. Xenon was applied after irradiation and additionally tested in combination with NMDAR antagonist memantine. RESULTS: The gas exposure system proved compatible with the CFA and resulted in a stable atmosphere of 50% xenon. Indications for the presence of glutamate receptor subunits were present in glioblastoma-derived and HeLa cells. Significantly reduced clonogenic survival by xenon was shown in U87 and U251 at irradiation doses of 4-8 Gy and 2, 6 and 8 Gy, respectively (p < 0.05). Clonogenic survival was further reduced by the addition of memantine, showing a significant effect at 2-8 Gy for both glioblastoma cell lines (p < 0.05). Xenon did not significantly reduce the surviving fraction of HeLa cells until a radiation dose of 8 Gy. CONCLUSION: The developed system allows for testing of gaseous agents with CFA. As a proof of concept, we have, for the first time, unveiled indications of radiosensitizing properties of xenon gas in glioblastoma.

Evaluation of the biocompatibility of fish skin collagen with the mesenchymal stem cells in in vitro cultures.

There are scarce published data suggesting, that collagen extracted from fish skin may be an attractive alternative to mammalian-derived collagen for the in vitro cell cultures. In this study, we investigated proliferation potential and differentiation capability into osteogenic and adipogenic lineages of rat adipose-derived mesenchymal stem cells (rASCs) and human adipose-derived mesenchymal stem cells (hASCs) cultured on collagen extracted from silver carp and African sharptooth catfish skins, compared with commercially available mammalian collagen and collagen-free culture dishes. Our results revealed no significant differences between fish collagen and mammalian collagen in supporting cell viability and proliferation capacity. Fish-derived collagen is a cheap material derived from production waste, does not contain transmissible pathogens of mammalian origin, supports human cell cultures at comparable level to conventional collagen sources, and may be considered as the product of choice for the in vitro cell cultures.

Variable RBE in proton radiotherapy: a comparative study with the predictive Mayo Clinic Florida microdosimetric kinetic model and phenomenological models of cell survival.

Objectives. (1) To examine to what extent the cell- and exposure- specific information neglected in the phenomenological proton relative biological effectiveness (RBE) models could influence the computed RBE in proton therapy. (2) To explore similarities and differences in the formalism and the results between the linear energy transfer (LET)-based phenomenological proton RBE models and the microdosimetry-based Mayo Clinic Florida microdosimetric kinetic model (MCF MKM). (3) To investigate how the relationship between the RBE and the dose-mean proton LET is affected by the proton energy spectrum and the secondary fragments.Approach. We systematically compared six selected phenomenological proton RBE models with the MCF MKM in track-segment simulations, monoenergetic proton beams in a water phantom, and two spread-out Bragg peaks. A representative comparison within vitrodata for human glioblastoma cells (U87 cell line) is also included.Main results. Marked differences were observed between the results of the phenomenological proton RBE models, as reported in previous studies. The dispersion of these models' results was found to be comparable to the spread in the MCF MKM results obtained by varying the cell-specific parameters neglected in the phenomenological models. Furthermore, while single cell-specific correlation between RBE and the dose-mean proton LET seems reasonable above 2 keVµm-1, caution is necessary at lower LET values due to the relevant contribution of secondary fragments. The comparison within vitrodata demonstrates comparable agreement between the MCF MKM predictions and the results of the phenomenological models.Significance. The study highlights the importance of considering cell-specific characteristics and detailed radiation quality information for accurate RBE calculations in proton therapy. Furthermore, these results provide confidence in the use of the MCF MKM for clonogenic survival RBE calculations in proton therapy, offering a more mechanistic approach compared to phenomenological models.

Toward a Transportable Cell Culture Platform for Evaluating Radiotherapy Dose Modifying Factors.

The current tools for validating dose delivery and optimizing new radiotherapy technologies in radiation therapy do not account for important dose modifying factors (DMFs), such as variations in cellular repair capability, tumor oxygenation, ultra-high dose rates and the type of ionizing radiation used. These factors play a crucial role in tumor control and normal tissue complications. To address this need, we explored the feasibility of developing a transportable cell culture platform (TCCP) to assess the relative biological effectiveness (RBE) of ionizing radiation. We measured cell recovery, clonogenic viability and metabolic viability of MDA-MB-231 cells over several days at room temperature in a range of concentrations of fetal bovine serum (FBS) in medium-supplemented gelatin, under both normoxic and hypoxic oxygen environments. Additionally, we measured the clonogenic viability of the cells to characterize how the duration of the TCCP at room temperature affected their radiosensitivity at doses up to 16 Gy. We found that (78±2)% of MDA-MB-231 cells were successfully recovered after being kept at room temperature for three days in 50% FBS in medium-supplemented gelatin at hypoxia (0.4±0.1)% pO2, while metabolic and clonogenic viabilities as measured by ATP luminescence and colony formation were found to be (58±5)% and (57±4)%, respectively. Additionally, irradiating a TCCP under normoxic and hypoxic conditions yielded a clonogenic oxygen enhancement ratio (OER) of 1.4±0.6 and a metabolic OER of 1.9±0.4. Our results demonstrate that the TCCP can be used to assess the RBE of a DMF and provides a feasible platform for assessing DMFs in radiation therapy applications.

Using Bland-Altman Analysis to Identify Appropriate Clonogenic Assay Colony Counting Techniques.

OBJECTIVE: Determine the interchangeability of various methods utilized for counting colonies in clonogenic assays. METHODS: Clonogenic assays of 2 head and neck cancer cell lines were counted through 4 different counting modalities: Manual counting pen, via microscope, 1 publicly available automated algorithm, and a semiautomated algorithm presented by the authors. Each method counted individual wells (N = 24). Pen and microscopic counts were performed by 2 observers. Parameters included both low-growth (<150 colonies/well) and high-growth (>150 colonies/well) cell lines. Correlational and Bland-Altman analyses were performed using SPSS software. RESULTS: Interobserver manual pen count correlation R2 value in both growth conditions was 0.902; controlling for only low-growth conditions decreased R2 to 0.660. Correlation of microscopic versus pen counts R2 values for observers 1 and 2 were 0.955 and 0.775, respectively. Comparing techniques, Bland-Altman revealed potential bias with respect to the magnitude of measurement (P < .001) for both observers. Correlation of microscopic counts for both interobserver (R2 = 0.902) and intraobserver (R2 = 0.916) were analyzed. Bland-Altman revealed no bias (P = .489). Automated versus microscopic counts revealed no bias between methodologies (P = .787) and a lower correlation coefficient (R2 = 0.384). Semiautomated versus microscopic counts revealed no bias with respect to magnitude of measurement for either observer (P = .327, .229); Pearson correlation was 0.985 (R2 = 0.970) and 0.965 (R2 = 0.931) for observer 1 and 2. Semiautomated versus manual pen colony counts revealed a significant bias with respect to magnitude of measurement (P < .001). CONCLUSION: Counting with a manual pen demonstrated significant bias when compared to microscopic and semiautomated colony counts; 2 methods were deemed to be interchangeable. Thus, training algorithms based on manual counts may introduce this bias as well. Algorithms trained to select colonies based on size (pixels2) and shape (circularity) should be prioritized. Solely relying on Bland-Altman or correlational analyses when determining method interchangeability should be avoided; they rather should be used in conjunction.

Primary explants of the postnatal thymus allow the expansion of clonogenic thymic epithelial cells that constitute thymospheres.

BACKGROUND: Thymic epithelial cells (TECs) are responsible for shaping the repertoires of T cells, where their postnatal regeneration depends on a subset of clonogenic TECs. Despite the implications for regenerative medicine, their cultivation and expansion remain challenging. Primary explant cell culture is a technique that allows the seeding and expansion of difficult-to-culture cells. Here, we report a reliable and simple culture system to obtain functional TECs and thymic interstitial cells (TICs). METHODS: To establish primary thymic explants, we harvested 1 mm cleaned fragments of thymus from 5-week-old C57/BL6 mice. Tissue fragments of a complete thymic lobe were placed in the center of a Petri dish with 1 mL of DMEM/F-12 medium supplemented with 20% fetal bovine serum (FBS) and 1% penicillin‒streptomycin. To compare, thymic explants were also cultivated by using serum-free DMEM/F-12 medium supplemented with 10% KnockOut™. RESULTS: We obtained high numbers of functional clonogenic TECs and TICs from primary thymic explants cultivated with DMEM/F-12 with 20% FBS. These cells exhibited a highly proliferative and migration profile and were able to constitute thymospheres. Furthermore, all the subtypes of medullary TECs were identified in this system. They express functional markers to shape T-cell and type 2 innate lymphoid cells repertoires, such as Aire, IL25, CCL21 and CD80. Finally, we also found that ≥ 70% of lineage negative TICs expressed high amounts of Aire and IL25. CONCLUSION: Thymic explants are an efficient method to obtain functional clonogenic TECs, all mTEC subsets and different TICs Aire+IL25+ with high regenerative capacity.

High-Content and High-Throughput Clonogenic Survival Assay Using Fluorescence Barcoding.

The Clonogenic Survival Assay (CSA) is a fundamental tool employed to assess cell survival and proliferative potential in cancer research. Despite its importance, CSA faces limitations, primarily its time- and labor-intensive nature and its binary output. To overcome these limitations and enhance CSA's utility, several approaches have been developed, focusing on increasing the throughput. However, achieving both high-content and high-throughput analyses simultaneously has remained a challenge. In this paper, we introduce LeGO-CSA, an extension of the classical CSA that employs the imaging of cell nuclei barcoded with fluorescent lentiviral gene ontology markers, enabling both high-content and high-throughput analysis. To validate our approach, we contrasted it with results from a classical assay and conducted a proof-of-concept screen of small-molecule inhibitors targeting various pathways relevant to cancer treatment. Notably, our results indicate that the classical CSA may underestimate clonogenicity and unveil intriguing aspects of clonal cell growth. We demonstrate the potential of LeGO-CSA to offer a robust approach for assessing cell survival and proliferation with enhanced precision and throughput, with promising implications for accelerating drug discovery and contributing to a more comprehensive understanding of cellular behavior in cancer.

MicroRNA-363-3p inhibits colorectal cancer progression by targeting interferon-induced transmembrane protein 1.

BACKGROUND: The molecular mechanisms of colorectal cancer development and progression are far from being elucidated. AIM: To investigate the role of microRNA-363-3p (miR-363-3p) in the progression of colorectal cancer. METHODS: Real-time polymerase chain reaction was performed to detect miRNA expression in human colorectal cancer tissues and paired normal colorectal tissues. PITA 6 was utilized to predict the targets of miR-363-3p. Dual-luciferase reporter system was used to validate the target of miR-363-3p. Plate colony formation assay and wound-healing assay were performed to evaluate cancer cells' clonogenic survival ability and migration ability, respectively. Cell proliferation was examined by cell counting kit-8 assay. Immunohistochemical staining was used to determine the expression level of interferon-induced transmembrane protein 1 (IFITM1) in colorectal cancer tissues and adjacent tissues. The TCGA and GTEx databases were used to compare the expression levels of IFITM1 mRNA in colorectal cancer tissues and normal colorectal tissues and analyze the correlation between the expression levels of IFITM1 mRNA and overall survival and disease-free survival of patients. A colorectal cancer cell line with a deficiency of IFITM1 was constructed, and the regulation effect of IFITM1 on the clonogenic growth of colorectal cancer cells was clarified. RESULTS: MiR-363-3p was decreased in colorectal cancer tissues compared to normal colorectal tissues. IFITM1 was characterized as a direct target of miR-363-3p. Overexpression of miR-363-3p led to decreased clonogenic survival, proliferation, and migration of colorectal cancer cells, which could be reversed by forced IFITM1 expression. CONCLUSION: MiR-363-3p can constrain clonogenic survival, proliferation, and migration of colorectal cancer cells via targeting IFITM1.

Chemical composition and anti-proliferative activity of essential oils from some medicinal plants from Cachicadán, Región La Libertad, Perú.

This study evaluated the chemical composition and anti-proliferative activity of essential oils (EOs) obtained by hydrodistillation from seven medicinal plants from Cachicadán, La Libertad Región, Perú. Limonene (0.64 to 44.43%) and linalool (0.36 to 2.12%) were identified in all EOs by gas chromatography coupled to mass spectrometry analysis. The major components (relative intensity ≥ 10%) were cis-dihydro carvone, carvone, and cis-piperitone epoxide for Minthostachys mollis leaves; ß-pinene, limonene, and ledol for Lepechinia heteromorpha leaves; limonene, neral, and geranial for Aloysia citriodora, both leaves and flowers; α-pinene, and limonene for Myrcianthes myrsinoides leaves; and α-pinene, ß-myrcene, and (E)-ß-Ocimene for Dalea carthagenensis leaves. Constituted by (Z)-ß-ocimene, dihydrotagetone, (Z)-tagetone, and car-3-en-2-one, EO of Tagetes minuta leaves induced an irreversible cytostatic effect against MCF-7 human breast tumor cells. Further in vivo studies must be carried out to establish the safe and efficient dose of T. minuta EO as adjuvant treatment in oncological therapies.

TFF3 promotes clonogenic survival of colorectal cancer cells through upregulation of EP4 via activation of STAT3.

Background: While growing evidence indicates the importance of TFF3 in cancer, the molecular mechanism of its action in cancer remains largely unknown. Clonogenic survival is a key ability for tumor cells, which is interpreted as a trait of cancer cells with tumor-initiating capabilities. We investigated the effect and the underlying mechanisms of TFF3 on the clonogenic survival of colorectal cancer (CRC) cells. Methods: Expression of TFF3 in CRC tissues and matched paracancerous tissues was determined by western blotting. Colony formation assays were performed to evaluate the clonogenic survival ability of CRC cells. PTGER4 mRNA expression was detected by quantitative polymerase chain reaction. PTGER4 promoter activity was determined by luciferase reporter assay. STAT3 nuclear localization was investigated using immunofluorescence staining. Expression of TFF3 and EP4 in CRC tissues was determined by immunohistochemistry. Results: TFF3 knockout led to decreased clonogenic survival of CRC cells, while overexpression of TFF3 resulted in the opposite effect. EP4 was found to be upregulated by TFF3 at both the mRNA and protein level. Moreover, EP4 antagonist abrogated TFF3-mediated clonogenic survival of CRC cells. PGE2 and EP4 agonist could restore the effect of TFF3 knockout on the clonogenic survival of CRC cells. Furthermore, TFF3 promoted STAT3 activation and nuclear localization. Activated STAT3 bound to PTGER4 promoter, the gene encoding for EP4, and facilitated PTGER4 transcription. Conclusions: TFF3 promotes clonogenic survival of CRC cells via upregulating EP4 expression.

Relative Biological Effectiveness (RBE) of [64Cu]Cu and [177Lu]Lu-NOTA-panitumumab F (ab')2 radioimmunotherapeutic agents vs. γ-radiation for decreasing the clonogenic survival in vitro of human pancreatic ductal adenocarcinoma (PDAC) cells.

INTRODUCTION: Our objective was to compare [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 radioimmunotherapy (RIT) agents for decreasing the clonogenic survival fraction (SF) in vitro of EGFR-positive human pancreatic ductal adenocarcinoma (PDAC) cell lines and estimate the relative biological effectiveness (RBE) vs. γ-radiation (XRT). METHODS: EGFR-positive PDAC cell lines (AsPC-1, PANC-1, MIAPaCa-2, Capan-1) and EGFR-knockout PANC-1 EGFR KO cells were treated in vitro for 18 h with (0-19.65 MBq; 72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 or XRT (0-8 Gy) followed by clonogenic assay. The SF was determined after culturing single treated cells for 14 d. Cell fractionation studies were performed for cells incubated with 1 MBq (72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 for 1, 4, or 24 h to estimate the time-integrated activity (Ã) on the cell surface, cytoplasm, nucleus and medium. Radiation absorbed doses in the nucleus were calculated by multiplying à by S-factors calculated by Monte Carlo N Particle (MCNP) modeling using monolayer cell culture geometry. The SF of PDAC cells was plotted vs. dose and fitted to a linear quadratic model to estimate the dose required to decrease the SF to 0.1 (D10). The D10 for RIT agents were compared to XRT to estimate the RBE. DNA double-strand breaks (DSBs) caused by [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 continuous exposure for 5 h or 20 h were probed by immunofluorescence for γ-H2AX. Relative EGFR expression of PDAC cells was assessed by flow cytometry (scored + to +++) and cell doubling times for untreated cells were determined. RESULTS: The D10 for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 9.1 Gy (PANC-1) to 39.9 Gy (Capan-1). The D10 for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 11.7 Gy (AsPC-1) to 170.8 Gy (Capan-1). The D10 for XRT ranged from 2.5 Gy (Capan-1) to 6.7 Gy (PANC-1 EGFR KO). D10 values were not correlated with EGFR expression over a relatively narrow range (++ to +++) or with cell doubling times. Based on D10 values, PANC-1 EGFR KO cells were 1.6-fold less sensitive than PANC-1 cells to [64Cu]Cu-NOTA-panitumumab F(ab')2 and 1.9-fold less sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2. The RBE for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 0.06 for Capan-1 cells to 0.45 for PANC-1 cells. The RBE for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 0.015 for Capan-1 cells to 0.28 for AsPC-1 cells. DNA DSBs were detected in PDAC cells exposed to [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 but were not correlated with the SF of the cells. CONCLUSIONS: We conclude that at the same dose delivered to the cell nucleus [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 were less radiobiologically effective than XRT for decreasing the SF of human PDAC cells, but [64Cu]Cu-NOTA-panitumumab F(ab')2 was more cytotoxic than [177Lu]Lu-NOTA-panitumumab F(ab')2 except for AsPC-1 cells which were more sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: This study demonstrates that higher radiation doses may be required for RIT than XRT to achieve radiobiologically equivalent effects when used to treat PDAC.

Parameterisation and cellular evaluation of poly(ethylene) oxide-coated erbium oxide in MCF-7 cells as MRI diagnostic nanofibres.

The novelty of this work is the conjugation of poly(ethylene) oxide (PEO) with the erbium oxide (Er2O3) nanoparticles using the electrospinning technique. In this work, synthesised PEO-coated Er2O3 nanofibres were characterised and evaluated for their cytotoxicity to assess their potential use as diagnostic nanofibres for magnetic resonance imaging (MRI). PEO has significantly impacted nanoparticle conductivity due to its lower ionic conductivity at room temperature. The findings showed that the surface roughness was improved over the nanofiller loading, implying an improvement in cell attachment. The release profile performed for drug-controlling purposes has demonstrated a stable release after 30 min. Cellular response in MCF-7 cells showed high biocompatibility of the synthesised nanofibres. The cytotoxicity assay results showed that the diagnostic nanofibres had excellent biocompatibility, indicating the feasibility for diagnosis purposes. With excellent contrast performance, the PEO-coated Er2O3 nanofibres developed novel T2 and T1-T2 dual-mode MRI diagnostic nanofibres leading to better cancer diagnosis. In conclusion, this work has demonstrated that the conjugation of PEO-coated Er2O3 nanofibres improved the surface modification of the Er2O3 nanoparticles as a potential diagnostic agent. Using PEO in this study as a carrier or polymer matrix significantly influenced the biocompatibility and internalisation efficiency of the Er2O3 nanoparticles without triggering any morphological changes after treatment. This work has suggested permissible concentrations of PEO-coated Er2O3 nanofibres for diagnostic uses.

Generation of Radioresistant Prostate Cancer Cells.

The development of in vitro isogenic models of radioresistance through exposure to fractionated radiation is an increasingly used approach to investigate the mechanisms of radioresistance in cancer cells. Owing to the complex nature of the biological effect of ionizing radiation, the generation and validation of these models requires the careful consideration of radiation exposure protocols and cellular endpoints. This chapter presents a protocol we used to derive and characterize an isogenic model of radioresistant prostate cancer cells. This protocol may be applicable to other cancer cell lines.

Generation and Characterization of an Isogenic Cell Line Model of Radioresistant Esophageal Adenocarcinoma.

Radiation therapy is a cornerstone of cancer treatment worldwide. Unfortunately, in many cases, it does not control tumor growth, and many tumors display treatment resistance. The molecular pathways leading to treatment resistance in cancer have been subject to research for many years. Isogenic cell lines with divergent radiosensitivities are an extremely useful tool to study the molecular mechanisms that underpin radioresistance in cancer research, as they reduce the genetic variation that is present in patient samples and cell lines of different origin, thus allowing the elucidation of molecular determinants of radioresponse. Here, we describe the process of generating an in vitro isogenic model of radioresistant esophageal adenocarcinoma by chronic irradiation of esophageal adenocarcinoma cells with clinically relevant doses of X-ray radiation. We also characterize cell cycle, apoptosis, reactive oxygen species (ROS) production, DNA damage and repair in this model to investigate the underlying molecular mechanisms of radioresistance in esophageal adenocarcinoma.