Affected Tumor Cells Research Articles

Magnetic Resonance Imaging in Breast Cancer Tissue In Vitro after PDT Therapy.

Photodynamic therapy (PDT) is increasingly used in modern medicine. It has found application in the treatment of breast cancer. The most common cancer among women is breast cancer. We collected cancer cells from the breast from the material received after surgery. We focused on tumors that were larger than 10 mm in size. Breast cancer tissues for this quantitative non-contrast magnetic resonance imaging (MRI) study could be seen macroscopically. The current study aimed to present findings on quantitative non-contrast MRI of breast cancer cells post-PDT through the evaluation of relaxation times. The aim of this work was to use and optimize a 1.5 T MRI system. MRI tests were performed using a clinical scanner, namely the OPTIMA MR360 manufactured by General Electric HealthCare. The work included analysis of T1 and T2 relaxation times. This analysis was performed using the MATLAB package (produced by MathWorks). The created application is based on medical MRI images saved in the DICOM3.0 standard. T1 and T2 measurements were subjected to the Shapiro-Wilk test, which showed that both samples belonged to a normal distribution, so a parametric t-test for dependent samples was used to test for between-sample variability. The study included 30 sections tested in 2 stages, with consistent technical parameters. For T1 measurements, 12 scans were performed with varying repetition times (TR) and a constant echo time (TE) of 3 ms. For T2 measurements, 12 scans were performed with a fixed repetition time of 10,000 ms and varying echo times. After treating samples with PpIX disodium salt and bubbling with pure oxygen, PDT irradiation was applied. The cell relaxation time after therapy was significantly shorter than the cell relaxation time before PDT. The cells were exposed to PpIX disodium salt as the administered pharmacological substance. The study showed that the therapy significantly affected tumor cells, which was confirmed by a significant reduction in tumor cell relaxation time on the MRI results.

The impact of heat source and chemical reaction on MHD blood flow through permeable bifurcated arteries with tilted magnetic field in tumor treatments

In this research work, we investigate the influence of heat source and chemical reaction on electro-magneto-hydrodynamic (EMHD) blood flow through bifurcated arteries with external tilted magnetic field for treating tumor. The potential electric field applied along the bifurcated arterial wall, accurately described the Poisson-Boltzmann equation. We modeled the EMHD blood flow to obtain the non-dimensionalized form of the equations. We converted the modeled equations to ordinary differential equations by the use of suitable variables. Exact solutions of the converted equations are calculated by the method of undetermined coefficients and the results obtained with the aid of Mathcad software were simulated and presented graphically. From the graphical representation of results, we observed that increase in Joule heating and Eckert number, increases the temperature distribution in the affected tumor cells which prevent high thermal radiation exposure from killing the healthy cells within the tumor region. The curves of the wall shear stress seem to be greater in the converging region in comparison to the diverging region, but when the strength of magnetic field and thermal radiation parameters increase the wall shear stress decreases at the bifurcated wall where blockage may likely occur due to the development of boundary layers on the inner walls of the bifurcated region. By increasing the heat radiation parameter, we observed that the curves representing both velocity and temperature profiles increase rapidly from the origin and the velocity of blood flow varies directly for the converging, diverging and the tumor regions of the bifurcated arteries. Thus, thermal radiation effect is a result of the higher rate of heat transfer at the vessel walls. Further, combining the electromagnetic field and the heat radiation together gives new insights of the physical properties of blood flow in the body system network which is essential for health practitioners and clinicians.

Antimicrobial activity on phytopathogenic bacteria and yeast, cytotoxicity and solubilizing capacity of deep eutectic solvents

The toxicity on oenological yeasts and plant pathogens of eight deep eutectic solvents (DESs) composed of ChCl:Sucrose (1:2), ChCl:1,4-butanediol (1:5), ChCl:Xylitol (2:1), ChCl:1,2-propanediol (1:1), Fructose:Glucose:Sucrose (1:1:1), Betaine:Sucrose (2:1), Betaine:Sucrose (4:1) and Fructose-Glucose-Sucrose (2:3.6:1) was evaluated and compared with the classic solvents dimethylsulfoxide (DMSO), ethanol and glycerol. Most yeast and bacteria were tolerant to DESs consisting of three sugars in a concentration range of 75–600 x 103mg/L for yeasts and 75–1200 x 103mg/L for bacteria. These DESs showed less toxicity than glycerol or DMSO for most microorganisms. The effect of six DESs, ChCl:Sucrose (1:2), ChCl:Xylitol (2:1), Fructose:Glucose:Sucrose (1:1:1), Betaine:Sucrose (2:1), Betaine:Sucrose (4:1) and Fructose-Glucose-Sucrose (2:3.6:1) in different human cancer cell lines (Caco-2, HeLa and HepG2 cells), as well as in peripheral blood mononuclear cells (PBMCs) from healthy volunteers, was studied using flow cytometry. As a result, DESs at concentrations below 1%, affected tumor cells; however, healthy PBMCs were unaffected. In addition, the solubility of poorly-soluble subtances in water (quercetin, phenylmethylsulfonyl fluoride (PFMS), camptothecin (CPT), oleanolic acid, palmitic acid and Red O oil) was evaluated in all DESs previously tested plus two organic acidbased DESs, Betaine:Levulinic acid (1:2) and ChCl:Glycolic acid:Oxalic acid (1:1.6:0.4). All they were compared with conventional solvents (water, DMSO or ethanol) to determine their efficacy as drug solvents. As a result, DESs solubilized quercetin and CPT in the same range as conventional solvents. The antioxidant properties of quercetin solubilized in two DESs and in DMSO were studied in Caco-2 cells. A solution of tert-butyl hydroperoxide (TBH) was used as an inducer of intracellular reactive oxygen species (ROS), resulting in that quercetin's ability to reduce ROS production did not differ when it was solubilized in DESs or DMSO. In this study, we determined the low toxicity of the DESs analyzed on oenological yeasts, phytopathogenic microorganisms and on healthy human cells. The toxicity of DESs on cancer cell lines was also showed. In addition, the ability of DESs to dissolve poorly water-soluble compounds or other substances of interest was also demonstrated, suggesting their use as safe solvents or cryoprotectors useful at an industrial level.

Abstract PR7: Epigenetic deregulation in LSD1-deficient luminal mammary tumor cells leads to their increased metastasis via reprogramming of the immune microenvironment

Abstract It has become increasingly recognized that epigenetic deregulation makes significant contributions to metastasis. Mutations or deregulated expression of epigenetic regulators can alter expression of key cancer-related genes in tumor cells and may contribute to metastatic progression by affecting interaction of tumor cells with their immune microenvironment. LSD1 (KDM1A) is a histone demethylase that mainly serves as a transcriptional repressor by removing methyl groups from mono- and di-methylated lysine 4 on histone H3. In human breast cancer, LSD1 homozygous deletions and mutations are found in ~1-2% metastatic cases, suggesting that it may function as a metastasis suppressor. Consistent with this, in a mouse model of luminal breast cancer, MMTV-PyMT, we found that induced loss or inhibition of LSD1 led to a significant increase in lung metastasis. Characterization of the affected tumor cells showed a profound upregulation of many immune-related genes in LSD1-deficient cells, including genes for most MHC class I (MHC-I) (classical and non-classical) molecules, interferon and immune checkpoint pathways. FACS analysis revealed significant upregulation of the CD4+ T cell and monocytic myeloid-derived suppressor cell (MDSC) populations, and downregulation of CD8+ T-cell and NK-cell populations, in tumors with LSD1 deletion/inhibition. MHC-Is are ligands for inhibitory receptors on NK cells, and their interaction (e.g., interaction between a non-classical MHC-I, HLA-E [Qa-1 in mice] and CD94/NKG2A [on NK cells]) is a self-guarding mechanism to avoid killing of healthy “self” cells by NK cells. Upregulation of MHC-Is in Lsd1-null PyMT tumor cells may lead to suppression of NK cells. In fact, in a coculture system, NK cells exhibited reduced cytotoxicity toward Lsd1-null tumor cells. Under the in vivo setting, intraductal injection of PyMT tumor organoid cells to mammary glands of immunodeficient mice led to development of both primary tumors and lung metastasis; importantly, in NSG recipients (lack NK cells), both Lsd1-null and Lsd1-wild-type (wt) tumor cells formed lung metastatic lesions with similar sizes, whereas in SCID recipients (have NK cells), the sizes of metastatic lesions formed from Lsd1-wt tumor cells were significantly smaller than Lsd1-null cells. Collectively, these data suggest that epigenetic deregulation in LSD1-deficient luminal mammary tumor cells reprograms the tumor immune microenvironment, leading to reduced clearance of Lsd1-null PyMT tumor cells by NK cells, which may contribute to their increased metastasis. This study is not only important for understanding the immune mechanism underlying the metastasis-suppressive role of LSD1 in breast cancer, but also has important implications for immunotherapy: currently a strategy of combining checkpoint inhibitors with epigenetic drugs (e.g., LSD1 inhibitor) is being tested for improving immunotherapy; our study may help minimize the risk of (increased) metastasis potentially associated with this strategy. This abstract is also being presented as Poster B6. Citation Format: Dongxi Xiang, Zhe Li. Epigenetic deregulation in LSD1-deficient luminal mammary tumor cells leads to their increased metastasis via reprogramming of the immune microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr PR7.

Scattering-Induced Absorption Acts as a Cancer Treatment Monitor

Uncontrolled growth of ovarian cancer cells is the fifth leading cause of female cancer deaths. Here, we describe the role of scattering-induced absorption in monitoring the cancer treatment efficiency in real-time. We measure the optical interaction between the evanescent fields of microfiber and ovarian cancer inter-cellular medium at different treatment stages. By introducing the roughness of silica glass, we demonstrate that the treatment of tumor cells with GDC0032, a beta-sparing PI3K, induces both cells growth arrest and alter the spectral lines in a dose-dependent manner. The data support observed affected tumor cells with decrease in proliferation and their spatial distribution. Spectral absorption signatures are correlated with optical micrographs and western blot tests. These observations are mediated by surface scatterers out of silica glass material, form an essential step toward the development of early detection of response to cancer therapy.

Abstract 763: The regulation of miR-125b1-peroxiredoxin like 2A anti-oxidative activity in oral squamous cell carcinoma

Abstract Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth most common cancer worldwide. MicroRNAs are small non-coding RNAs that are involved in the modulation of biological/pathological properties. Peroxiredoxin like 2A (PRXL2A) has been reported to be an antioxidant protein that protects cells from oxidative stress. Our previous study identified an association between PRXL2A up-regulation in OSCC and a worse patient prognosis. The miR-125 family of genes drive pluripotent regulation across a wide variety of cancers. In this study, we identify the oncogene eligibility of PRXL2A and clarify miR-125b as its upstream regulator. Down-regulation of miR-125b can be observed in OSCC tumors. Lower miR-125b expression in tumors results in a worse patient prognosis at the relatively early stage. Reporter assays were able to validate that PRXL2A is a direct target of miR-125b. Exogenous miR-125b expression in OSCC cells results in increased oxidative stress and drug sensitivity, and suppressor activity that is paralleled by the knockout of PRXL2A gene. The suppressor activity of miR-125b is able to be rescued by PRXL2A, which suggests the existence of a miR-125b-PRXL2A regulatory axis that is part of OSCC pathogenesis. Nuclear factor erythroid-2-related factor was found to be a downstream effector of the miR-125b-PRXL2A cascade. As a whole, this study has pinpointed novel clues demonstrating that down-regulation of miR-125b suppressor underlies up-regulation of PRXL2A in OSCC, and this then protects the affected tumor cells from oxidative stress resulting in a worse prognosis. Citation Format: Yi-Fen Chen, Yun-Yen Wei, Cheng-Chieh Yang, Kuo-Wei Chang, Shu-Chun Lin. The regulation of miR-125b1-peroxiredoxin like 2A anti-oxidative activity in oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 763.

MSI2-TGF-β/TGF-β R1/SMAD3 positive feedback regulation in glioblastoma.

Glioblastoma is the most malignant glioma tumors with inevitable relapse and resistance to chemotherapy; however, the mechanisms driving chemoresistance remain to be fully elucidated. This study is to explore the molecular and cellular mechanisms involving in the chemoresistance of glioblastoma. The expression of musashi (MSI) RNA-binding protein in the tumor tissues and cells of glioblastoma was measured. The effects of MSI2 in epithelial-to-mesenchymal transition (EMT), resistance to temozolomide (TMZ), tumor cell invasion, migration, and proliferation and associated signaling were evaluated. High MSI2 expression was observed in the glioblastoma tissues. Silencing or overexpression of MSI2 significantly affected tumor cells invasion, migration, and proliferation. Silencing of MSI2 expression significantly inhibited O6-methylguanine-DNA methyltransferase (MGMT) expression and tumor growth, and reversed resistance to TMZ in xenograft tumor models. MSI2 expression regulated EMT through activating the transcription factors Snail and the TGFβ R1/SMAD3 signaling. Our study demonstrated a positive feedback loop of MSI2-TGFβ/SMAD3 signaling which activates the EMT and MGMT which may contribute to chemoresistance in glioblastoma. This study also highlights that MSI2 could be a new target for the therapy of glioblastoma.

MiR-125b suppresses oral oncogenicity by targeting the anti-oxidative gene PRXL2A

Oral squamous cell carcinoma (OSCC) is a globally prevalent malignancy. The molecular mechanisms of this cancer are not well understood and acquire elucidation. Peroxiredoxin like 2A (PRXL2A) has been reported to be an antioxidant protein that protects cells from oxidative stress. Our previous study identified an association between PRXL2A upregulation in OSCC and a worse patient prognosis. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in the modulation of biological/pathological properties. The miR-125 family of genes drive pluripotent regulation across a wide variety of cancers. In this study, we identify the oncogenic eligibility of PRXL2A and clarify miR-125b as its upstream regulator. Downregulation of miR-125b can be observed in OSCC tumors. Lower miR-125b expression in tumors results in a worse patient prognosis at the relatively early stage. Reporter assays are able to validate that PRXL2A is a direct target of miR-125b. Exogenous miR-125b expression in OSCC cells results in increased oxidative stress, increased drug sensitivity, and suppressor activity that is paralleled by the knockout of PRXL2A gene. The suppressor activity of miR-125b is able to be rescued by PRXL2A, which suggests the existence of a miR-125b-PRXL2A regulatory axis that is part of OSCC pathogenesis. Nuclear factor-erythroid 2-related factor 2 (NRF2) was found to be a downstream effector of the miR-125b-PRXL2A cascade. As a whole, this study has pinpointed novel clues demonstrating that downregulation of miR-125b suppressor underlies upregulation of PRXL2A in OSCC, and this then protects the affected tumor cells from oxidative stress.

Morphological changes induced by intraprostatic PSA-based vaccine in prostate cancer biopsies (phase I clinical trial)

Immunotherapy is a novel treatment for many tumors including prostate cancer. Little is known about the histological changes in prostate biopsies caused by the prostate-specific antigen (PSA)-based vaccine. This study evaluated the histopathological effects in prostate biopsies of recombinant fowlpox (rF) virus-based vaccine engineered to present the PSA and 3 costimulatory molecules (collectively labeled as PSA-TRICOM). This vaccine has shown that it can break tolerance of the PSA, and its administration directly into a tumor enables the affected tumor cells to act as antigen-presenting cells activating new T cells and broadening the immune response to recognize and kill tumor. We studied 10 patients with recurrent prostate cancer who had failed radiation therapy and/or androgen-deprivation therapy. Pre- and posttreatment biopsies were compared. Posttreatment biopsies induced 8 cases with residual adenocarcinoma despite evidences of treatment effect and inflammation, 2 cases did not show any residual tumor, and 1 one case did not have any inflammatory infiltrate or any evidence of treatment effect. The inflammatory infiltrate varied from mild to severe and was composed of mononuclear cells. Greater numbers of infiltrating CD8+ lymphocytes were identified around prostatic glands and within the epithelial lining. The most remarkable feature was the presence of increased eosinophils around the glands and stroma. Three cases showed areas of necrosis surrounded by lymphocytes and palisading epithelioid macrophages arranged in granuloma-like pattern with multinucleated giant cells. This description of these morphological changes induced by the PSA-TRICOM will help to interpret the results of future intratumoral vaccine therapy trials.

Upregulated Heat Shock Proteins After Hyperthermic Chemotherapy Point to Induced Cell Survival Mechanisms in Affected Tumor Cells From Peritoneal Carcinomatosis.

In patients with peritoneal carcinomatosis cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) represents a promising treatment strategy. Here, we studied the role of hyperthermic chemotherapy on heat shock protein (HSP) expression and induction of tumor cell death and survival. HSP27, HSP70, and HSP90 combined with effects on tumor cell proliferation and chemosensitivity were analyzed in human colon cancer. Hyperthermic chemotherapy resulted in significant HSP27/HSP70 and HSP90 gene/protein overexpression in analyzed HT-29/SW480/SW620 colon cancer cells and peritoneal metastases from patients displaying amplified expression of proliferation markers, proliferating cell nuclear antigen and antiapoptotic protein Bcl-xL. Moreover, functionally increased chemoresistance against 5-fluorouracil/mitomycin C and oxaliplatin after hyperthermic chemotherapy points to induced survival mechanisms in cancer cells. In conclusion, the results indicate that intracellular HSP-associated antiapoptotic and proliferative effects after hyperthermic chemotherapy negatively influence beneficial effects of hyperthermic chemotherapy-induced cell death. Therefore, blocking HSPs could be a promising strategy to further improve the rate of tumor cell death and outcome of patients undergoing HIPEC therapy.

Anaplastic lymphoma kinase (ALK) gene rearrangement in non-small cell lung cancer (NSCLC): Results of a multi-centre ALK-testing

BackgroundThe reliable identification of non-small cell lung cancers (NSCLC) with chromosomal breaks in the gene of the anaplastic lymphoma kinase (ALK) is crucial for the induction of therapy with ALK-inhibitors. In order to ensure a reliable detection of ALK-breaks by means of fluorescence in situ hybridization (FISH) testing, round robin tests are essential. In preparation of a nation (German)-wide round robin test we initiated a pre-testing phase involving 8 experts in FISH-diagnostics to identify NSCLC cases (n=10) with a pre-tested ALK-status. In addition, ALK immunohistochemistry (IHC) was performed to assess ALK protein expression. Material and methodsSections derived from a tissue microarray, each consisting of 3 cores from 10 NSCLC cases, were independently tested for ALK protein expression by IHC and genomic ALK-breaks by FISH involving 8 institutes of pathology. Based on a pre-screening, 5 cases were identified to be clearly ALK-break negative, whereas the remaining 5 cases were ALK-break positive including one case with low percentage (20%) of positive cells. The latter had been additionally tested by RT-PCR. ResultsThe 5 unequivocal ALK-break negative NSCLC were almost consistently scored negative by means of FISH and IHC by all 8 experts. Interestingly, 4 of the 5 cases with pre-defined ALK-breaks revealed homogenous FISH results whereas IHC for the detection of ALK protein expression showed heterogeneous results. The remaining case (low number of ALK-break positive cells) was scored negative by 3 experts and positive by the other 5. RT-PCR revealed the expression of an EML4-ALK fusion gene variant 1. ConclusionALK-break negative NSCLC cases revealed concordant homogeneous results by means of FISH and IHC (score 0–1) by all 8 experts. Discordant FISH results were raised in one ALK-break positive case with a low number of affected tumor cells. The remaining 4 ALK-break positive cases revealed concordant FISH data whereas the ALK-IHC revealed very diverse results. The cases with concordant FISH results provide an excellent basis for round robin ALK-FISH testing. As long as standardized ALK-IHC protocols are missing, ALK protein expression cannot by regarded as the method of choice for identification of patients eligible for treatment with ALK inhibitors.

Mutant p53 Gain-of-Function in Cancer

In its wild-type form, p53 is a major tumor suppressor whose function is critical for protection against cancer. Many human tumors carry missense mutations in the TP53 gene, encoding p53. Typically, the affected tumor cells accumulate excessive amounts of the mutant p53 protein. Various lines of evidence indicate that, in addition to abrogating the tumor suppressor functions of wild-type p53, the common types of cancer-associated p53 mutations also endow the mutant protein with new activities that can contribute actively to various stages of tumor progression and to increased resistance to anticancer treatments. Collectively, these activities are referred to as mutant p53 gain-of-function. This article addresses the biological manifestations of mutant p53 gain-of-function, the underlying molecular mechanisms, and their possible clinical implications.

Dying cells program their expedient disposal: serum amyloid P component upregulation in vivo and in vitro induced by photodynamic therapy of cancer

Serum amyloid P component (SAP) is known as a prototypic acute phase reactant in the mouse and the protein that binds to dying cells securing their swift disposal by phagocytes. Treatment of solid tumors by photodynamic therapy (PDT) triggers SAP production in the liver of host mice, its release in the circulation and accumulation in PDT-targeted lesions. In the present study, mouse Lewis lung carcinoma (LLC) cells treated in vitro by PDT are shown to upregulate their gene encoding SAP. This effect was manifested following PDT treatment mediated by various types of photosensitizers (Photofrin, BPD, mTHPC, ALA). Generated SAP protein was not detected in tissue supernatants but remained localized to producing PDT-treated cells. The upregulation of SAP gene was observed also in untreated IC-21 macrophages after they were co-incubated for 4 h with PDT-treated LLC cells. Based on these findings, SAP that accumulates in PDT-treated tumors may originate from both systemic sources (released from the liver as acute phase reactant) and local sources; the latter could include tumor cells directly sustaining PDT injury and macrophages invading the tumor that become stimulated by signals from these affected tumor cells. Since SAP gene upregulation in LLC cells increased with the lethality of PDT dose used for their treatment, we propose that cells sensing they are inflicted with mortal injury can turn on molecular programs insuring not only that they die an innocuous form of death (apoptosis) but also that once they are dead their elimination is (facilitated by SAP) swift and efficient.

Numerical abnormalities of the Cyclin D 1 gene locus on chromosome 11q13 in non-melanoma skin cancer

Deregulation of the cell-cycle G1-restriction point control via abnormalities of Rb-pathway components is a frequent event in the formation of cancer. The aim of this study was to evaluate numerical aberrations of the Cyclin D 1 (CCND 1, PRAD1, bcl-1) gene locus at chromosome 11q13 in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin and to compare it with the Cyclin D 1 protein expression. Fluorescence in situ hybridization with DNA-probes specific for the Cyclin D 1 gene locus and the centromere of chromosome 11 as well as immunostaining for Cyclin D 1 protein was applied on 5 μm serial paraffin sections. Six of the 30 (20%) SCCs showed additional Cyclin D 1 gene copies and 2/30 (6.6%) cases had a loss of the Cyclin D 1 gene locus in relation to the centromere 11 number. In contrast, only one of the 14 BCCs (7%) showed one additional Cyclin D 1 gene copy in relation to the centromere 11 number. None of the BCCs demonstrated aneusomy for chromosome 11 in contrast to SCCs, where it was found in 21/30 (70%) cases. Twenty-six of the 30 (86.6%) cutaneous SCCs and 13/14 (93%) BCCs expressed Cyclin D 1 protein. All SCCs and the BCC with additional Cyclin D 1 gene copies showed positivity for Cyclin D 1 protein. Both SCCs with less Cyclin D 1 gene copies than centromere 11 signals showed a weak protein expression. Our findings suggest that numerical abnormalities of the Cyclin D 1 gene locus could result in an altered gene-dose effect, possibly leading to an aberrant expression in affected tumor cells. This might result in deregulation of cell cycle control, eventually leading to uncontrolled cell cycle progression.

Tumor cell hypoxia and the hypoxia-response signaling system as a target for prostate cancer therapy.

The accumulation of cancerous cells within a growing prostate tumor can deprive them of adequate vascular support. Without this support, the affected tumor cells become hypoxic, a condition that is usually unfavorable for the further growth and survival of eukaryotic cells. Mammalian cells, however, have the ability of responding to a hypoxic environment by activating a "hypoxia-response" signaling system. Ultimately, this signaling system upregulates the expression of a network of gene products that increase the propensity of the cell to survive even in this adverse environment. With increasing evidence that hypoxia and an activated hypoxia-response signaling system can influence progression (via increased angiogenic propensity and apoptotic resistance) and the therapeutic responsiveness of prostate cancer cells, this review will examine the concept of targeting hypoxia or the hypoxia-response system of prostate tumor cells as a means to suppress prostate tumor progression and metastasis or perhaps even as a means for eliminating prostate tumors in advanced prostate cancer patients.

The selective cytotoxic effect of carotenoids and α-Tocopherol on human cancer cell lines in vitro

This study compares the toxic effects of the carotenoids, β-carotene and canthaxanthin, and α-tocopherol (vitamin E) on human tumor cells and their normal counterparts in vitro. Seven different malignant cell lines were examined: oral carcinoma (two cell lines), breast (two cell lines), lung carcinoma (two cell lines), and malignant melanoma. The in vitro cell culture assays showed a consistent morphologic change in the affected tumor cells following treatment with carotenoid or vitamin E. A rounding of the tumor cells and eventual lifting off the tissue culture plate were observed. These changes were apparent after 1 to 5 hours of treatment depending on the tumor cell line. Associated with these observable cellular changes were quantitative reductions in proliferation ( 3H-thymidine proliferation) and succinic dehydrogenase activity (MTT assay). In addition, there was a noticeable change in protein expression, with an increased expression of a 70-kD protein following treatment with β-carotene. This protein was associated with tumor cells showing a decrease in proliferation (oral carcinoma, malignant melanoma), but not with normal keratinocytes or melanocytes. These studies substantiate a selective cytotoxic effect on human tumor cell growth by carotenoids and α-tocopherol in vitro, and may provide an explanation of the therapeutic activity of these agents and their possible use in the treatment of premalignancy or early oral carcinoma.

Characterization and partial purification of a high molecular weight tumoricidal activity secreted by murine bone marrow macrophages.

Cultured murine bone marrow-derived macrophage (BMM phi) can be induced to secrete tumoricidal activity in vitro when activated with recombinant IFN-gamma and bacterial lipopolysaccharide (LPS). We have analyzed this activity for tumor specificity, relationship to tumor necrosis factor-alpha (TNF-alpha), serine proteases, and reactive nitrogen intermediates, and partially purified this activity by high pressure liquid chromatography. Cytolytic activity was recovered in conditioned culture supernatants of serum-free cultivated BMM phi treated with a combination of IFN-gamma and LPS but was not inducible by either stimulant alone. It selectively affected tumor cells of murine as well as human origin irrespective of sensitivity towards recombinant murine TNF-alpha (r-muTNF-alpha), but did not significantly affect non-tumorigenic cells of either species. It was inactivated by 56 degrees C, trypsin, and neuraminidase treatment, but could not be inhibited by neutralizing antibodies against r-muTNF-alpha or serine protease inhibitors. Tumoricidal activity was purified approximately 10-fold by gel filtration and eluted as a major peak with a Mr of 170 kDa, containing a single predominant protein band of approximately 170 kDa on SDS-PAGE analysis, which is shown to be a disulfide linked glycoprotein heterodimer of 110 and 58 kDa subunits (gp170). Expression of this glycoprotein was strongly dependent on activation of BMM phi by a combination of IFN-gamma and LPS but was only marginally induced by either stimulant alone. Furthermore, the level of gp170 expression was quantitatively correlated with the tumoricidal activity of BMM phi culture supernatants, whereas no such correlation was found with respect to the amount of secreted TNF-alpha or reactive nitrogen intermediates. These data demonstrate that activated murine BMM phi secrete a tumoricidal activity, which is not related to TNF-alpha, serine proteases, or reactive nitrogen intermediates, but is closely associated with a 170 kDa glycoprotein composed of two subunits with Mr's of 110 and 58 kDa.

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In vitro treatment of Lewis lung carcinoma cells with the polysaccharide levan was shown previously to reduce the oncogenicity of these cells by acting on the cell membrane. In the present study the direct effect of levan on the tumorigenicity of Lewis lung carcinoma in C57BL male mice was tested at different doses and intervals and temperatures of incubation. A dose-dependent decrease in tumorigenicity was observed: Doses of 0.5, 1, and 2 mg levan/2 X 10(5) cells/0.2 ml reduced tumor incidence by 30, 50, and 70%, respectively. Some degree of inhibition was observed even with a dose of 0.004 mg. The inhibitory effect was rapid; 5 minutes of incubation resulted in the same reduction in oncogenicity as 60 minutes. Inhibition at 0 degree C was as effective as inhibition at 37 degrees C. The lack of temperature effect indicates that enzymatic activity probably is not involved. The data presented here, together with previous data, suggest that levan induces a physical, rather than a chemical, change in the affected tumor cells. The polysaccharide appears to be loosely, noncovalently bound to the cell membrane.

The Cytological Effect of Chemicals on Tumors X

The damage to tumor cells following the application of Mitomycin C was studied from the viewpoints of cytology and cytochemistry in the MTK-sarcoma III of rats and EM tumor of mice.Cytological observations revealed the occurrence of abnormal mitotic figures of various types in affected tumor cells. The application of certain cytochemical methods has made it clear that the main effects of Mitomycin C is to damage the DNA in the resting nucleus and some influence to change the nature of the RNA in the nucleolus. It is apparent that these cytochemical changes may induce abnormal division in affected tumor cells.

Antimitotic action of maleuric acid.

Summary1. Maleuric acid produced mitotic inhibition in onion root-tip cells and an increase in proportion of mitotic cells in meta-phase, but little or no cytoplasmic or nuclear abnormality was observed. 2. A single intraperitoneal injection of maleuric acid into mice bearing the Ehrlich ascites tumor resulted in marked cytoplasmic blebbing of the tumor cells. Mitotic abnormalities produced by the treatment persisted for prolonged periods. 3. The affected tumor cells showed essentially normal patterns of free amino acids.