Interaction between dactinomycin and tumor necrosis factor in mesothelioma. Cachexia without oncolysis

Drug Repurposing of Selected Antibiotics: An Emerging Approach in Cancer Drug Discovery

Drug repurposing is a method of investigating new therapeutic applications for previously approved medications. This repurposing approach to "old" medications is now highly efficient, simple to arrange, and cost-effective and poses little risk of failure in treating a variety of disorders, including cancer. Drug repurposing for cancer therapy is currently a key topic of study. It is a way of exploring recent therapeutic applications for already-existing drugs. Theoretically, the repurposing strategy has various advantages over the recognized challenges of creating new molecular entities, including being faster, safer, easier, and less expensive. In the real world, several medications have been repurposed, including aspirin, metformin, and chloroquine. However, doctors and scientists address numerous challenges when repurposing drugs, such as the fact that most drugs are not cost-effective and are resistant to bacteria. So the goal of this review is to gather information regarding repurposing pharmaceuticals to make them more cost-effective and harder for bacteria to resist. Cancer patients are more susceptible to bacterial infections. Due to their weak immune systems, antibiotics help protect them from a variety of infectious diseases. Although antibiotics are not immune boosters, they do benefit the defense system by killing bacteria and slowing the growth of cancer cells. Their use also increases the therapeutic efficacy and helps avoid recurrence. Of late, antibiotics have been repurposed as potent anticancer agents because of the evolutionary relationship between the prokaryotic genome and mitochondrial DNA of eukaryotes. Anticancer antibiotics that prevent cancer cells from growing by interfering with their DNA and blocking growth of promoters, which include anthracyclines, daunorubicin, epirubicin, mitoxantrone, doxorubicin, and idarubicin, are another type of FDA-approved antibiotics used to treat cancer. According to the endosymbiotic hypothesis, prokaryotes and eukaryotes are thought to have an evolutionary relationship. Hence, in this study, we are trying to explore antibiotics that are necessary for treating diseases, including cancer, helping people reduce deaths associated with various infections, and substantially extending people's life expectancy and quality of life.

Antibiotics: Conventional Therapy and Natural Compounds with Antibacterial Activity-A Pharmaco-Toxicological Screening

Antibiotics are considered as a cornerstone of modern medicine and their discovery offers the resolution to the infectious diseases problem. However, the excessive use of antibiotics worldwide has generated a critical public health issue and the bacterial resistance correlated with antibiotics inefficiency is still unsolved. Finding novel therapeutic approaches to overcome bacterial resistance is imperative, and natural compounds with antibacterial effects could be considered a promising option. The role played by antibiotics in tumorigenesis and their interrelation with the microbiota are still debatable and are far from being elucidated. Thus, the present manuscript offers a global perspective on antibiotics in terms of evolution from a historical perspective with an emphasis on the main classes of antibiotics and their adverse effects. It also highlights the connection between antibiotics and microbiota, focusing on the dual role played by antibiotics in tumorigenesis. In addition, using the natural compounds with antibacterial properties as potential alternatives for the classical antibiotic therapy is discussed.

Antibiotics for cancer treatment: A double-edged sword

Various antibiotics have been used in the treatment of cancers, via their anti-proliferative, pro-apoptotic and anti-epithelial-mesenchymal-transition (EMT) capabilities. However, increasingly studies have indicated that antibiotics may also induce cancer generation by disrupting intestinal microbiota, which further promotes chronic inflammation, alters normal tissue metabolism, leads to genotoxicity and weakens the immune response to bacterial malnutrition, thereby adversely impacting cancer treatment. Despite the advent of high-throughput sequencing technology in recent years, the potential adverse effects of antibiotics on cancer treatments via causing microbial imbalance has been largely ignored. In this review, we discuss the double-edged sword of antibiotics in the field of cancer treatments, explore their potential mechanisms and provide solutions to reduce the potential negative effects of antibiotics.

Factors secreted by peritoneal macrophages are cytotoxic for transformed rat pleural mesothelium and mesothelioma cells

The report is devoted to the investigation of cytotoxic action of macrophages and asbestos on transformed mesothelium and mesothelioma cells, the characterization of its specificity, and the nature of the factors mediating it. The viability of different cells after asbestos exposure was studied in co-culture with macrophages. Mesothelioma cell lines obtained from tumors developed in vivo were the most sensitive to the cytotoxic action of macrophages and asbestos. Mesothelium cells of late passages and ras-transformed cell lines IAR2 and Rat1 were somewhat less sensitive, whereas untransformed cells of IAR2 and Rat1 lines and early passage mesothelium were low sensitive to that cytotoxic action. In experiments performed on Petri dishes with inserts that allowed treatment with asbestos of only one of two cell populations, it was shown that asbestos treatment of mesothelioma cells was necessary and sufficient for manifestation of cytotoxic effect (in the absence of macrophages asbestos caused very low cytotoxicity). The medium conditioned by macrophages was not cytototoxic by itself but it strongly enhanced cytotoxic action of asbestos on transformed mesothelium and mesothelioma cells but not on normal mesothelial cells and IAR2 and Rat1 cells (both normal and ras-transformed). The specificity of this augmenting effect for different toxicants was also investigated. It was shown that medium conditioned by macrophages enhanced cytotoxicity of hydrogen peroxide and sodium azide but not that of nonfibrous silicon dioxide, ethylmethanesulfonate, and sodium dodecylsulfate. The factor mediating this effect is thermolabile, non-dialyzable and protease-sensitive. Its m.w. is approximately 3-5 kD.

In vitro and in vivo studies of mesothelioma

Pleural mesothelioma is an asbestos-related malignancy characterized by progressive local growth, late metastases, and median survivals between 8 and 18 months. It is only recently that the in vitro and in vivo characteristics of the malignancy has been investigated. These investigations have been aided by the development of cell lines from patients with the disease, as well as lines developed from asbestos-exposed animals. Nude mouse models constructed with subcutaneous, intraabdominal, or intrathoracic innoculation of cultured cell lines or fresh tumor have been used for evaluating response to innovative therapies. Karyotyping has been performed on a number of cell lines and multiple abnormalities involving many chromosomes have been identified. Aneuploidy is commonly seen, along with reported non-random patterns of chromosomal aberrations. The role of tumor suppressor genes, including p53 is controversial. Multiple growth factors including PDGF are being investigated for a possible paracrine/autocrine loop, and PDGF receptors seem to be differentially expressed in mesothelioma cells compared to normal mesothelial cells. The role of cytokines in the pathophysiology of the disease, secreted either by the tumor cells themselves or by monocyte/macrophages in the local tumor environment, remains to be defined.

The effect of combining recombinant human tumor necrosis factor-alpha with local radiation on tumor control probability of a human glioblastoma multiforme xenograft in nude mice

PURPOSE

To evaluate the antitumor activity of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) on a human glioblastoma multiforme (U87) xenograft in nude mice, and to study the effect of combining rHuTNF-alpha with local radiation on the tumor control probability of this tumor model.

METHODS AND MATERIALS

U87 xenograft was transplanted SC into the right hindleg of NCr/Sed nude mice (7-8 weeks old, male). When tumors reached a volume of about 110 mm3, mice were randomly assigned to treatment: rHuTNF-alpha alone compared with normal saline control; or local radiation plus rHuTNF-alpha vs. local radiation plus normal saline. Parameters of growth delay, volume doubling time, percentage of necrosis, and cell loss factor were used to assess the antitumor effects of rHuTNF-alpha on this tumor. The TCD50 (tumor control dose 50%) was used as an endpoint to determine the effect of combining rHuTNF-alpha with local radiation.

RESULTS

Tumor growth in mice treated with a dose of 150 micrograms/kg body weight rHuTNF-alpha, IP injection daily for 7 consecutive days, was delayed about 8 days compared to that in controls. Tumors in the treatment group had a significantly longer volume doubling time, and were smaller in volume and more necrotic than matched tumors in control group. rHuTNF-alpha also induced a 2.3 times increase of cell loss factor. The administration of the above-mentioned dose of rHuTNF-alpha starting 24 h after single doses of localized irradiation under hypoxic condition, resulted in a significant reduction in TCD50 from the control value of 60.9 Gy to 50.5 Gy (p < 0.01).

CONCLUSION

rHuTNF-alpha exhibits an antitumor effect against U87 xenograft in nude mice, as evidenced by an increased delay in tumor growth as well as cell loss factor. Also, there was an augmentation of tumor curability when given in combination with radiotherapy, resulting in a significantly lower TCD50 value in the treatment vs. the control groups.

Chemosensitivity and cytokine sensitivity of malignant mesothelioma

Malignant mesothelioma arises in serosal tissues, is locally invasive, and is usually resistant to chemotherapeutic agents used clinically. To determine whether resistance to cytotoxic drugs was an inherent characteristic of mesothelioma cells, we performed in vitro chemosensitivity testing on five fully characterised human malignant mesothelioma cell lines and, for comparison, on three lines representative of clinically drug-resistant solid-tissue carcinomas using the MTT (tetrazolium bromide) assay system. Mesothelioma cell lines were intrinsically resistant to eight common antineoplastic drugs, with concentrations that produced a 50% reduction in optical density (IC50 values) for all drugs being equivalent, if not higher, for mesothelioma cell lines as compared with lung and colon carcinoma cell lines. We then investigated the direct anti-mesothelioma activity of recombinant human cytokines with their antineoplastic properties. All five mesothelioma cell lines were resistant to tumour necrosis factor, but they displayed varying degrees of sensitivity to interferons (IFNs). IFN gamma directly inhibited the growth of two of five mesothelioma lines. IFN alpha displayed little activity against four of five mesothelioma lines. The mesothelioma cells that were sensitive to IFN alpha were resistant to IFN gamma, indicating that sensitivity to IFNs is not a genetic characteristic of malignant mesothelioma cells. Significant interactions between cytokines in combination were not observed.