Mitotic MTH1 inhibitor TH1579 induces PD-L1 expression and inflammatory response through the cGAS-STING pathway.

The mitotic MTH1 inhibitor TH1579 is a dual inhibitor that inhibits mitosis and incorporation of oxidative DNA damage and leads to cancer-specific cell death. The response to immune checkpoint inhibitor (ICI) treatment is often augmented by DNA damaging agents through the cGAS-STING pathway. This study investigates whether TH1579 can improve the efficacy of immune checkpoint blockades through its immunomodulatory properties. Various human and murine cancer cell lines were treated with mitotic MTH1i TH1579, and the expression of PD-L1 and T-cell infiltration-related chemokines was analysed by flow cytometry and real-time qPCR. Syngeneic mouse models were established to examine the combined effect of TH1579 and PD-L1 blockade. In our investigation, we found that TH1579 upregulates PD-L1 expression at both the protein and mRNA levels in human cancer cell lines. However, in murine cell lines, the increase was less pronounced. An in vivo experiment in a syngeneic mouse melanoma model showed that TH1579 treatment significantly increased the efficacy of atezolizumab, an anti-PD-L1 antibody, compared to vehicle or atezolizumab monotherapy. Furthermore, TH1579 exhibited immune-modulatory properties, elevating cytokines such as IFN-ß and chemokines including CCL5 and CXCL10, in a cGAS-STING pathway-dependent manner. In conclusion, TH1579 has the potential to improve ICI treatment by modulating immune checkpoint-related proteins and pathways.

Repurposing Study of 4-Acyl-1-phenylaminocarbonyl-2-substituted-piperazine Derivatives as Potential Anticancer Agents-In Vitro Evaluation against Breast Cancer Cells.

Breast cancer is the most common type of cancer in women. Although current treatments can increase patient survival, they are rarely curative when the disease is advanced (metastasis). Therefore, there is an urgent need to develop new cytotoxic drugs with a high selectivity toward cancer cells. Since repurposing approved drugs for cancer therapy has been a successful strategy in recent years, in this study, we screened a library of antiviral piperazine-derived compounds as anticancer agents. The compounds included a piperazine ring and aryl urea functions, which are privileged structures present in several anti-breast cancer drugs. The selective cytotoxic activity of a set of thirty-four 4-acyl-2-substituted piperazine urea derivatives against MCF7 breast cancer cells and MCF 10A normal breast cells was determined. Compounds 31, 32, 35, and 37 showed high selective anticancer activity against breast cancer cells and were also tested against another common type of cancer, non-small cell lung cancer (A549 lung cancer cells versus MRC-5 lung normal cells). Compounds 35 and 37 also showed selectivity against lung cancer cells. These results suggest that compounds 35 and 37 may be promising hit compounds for the development of new anticancer agents.

Artificial Diets with Altered Levels of Sulfur Amino Acids Induce Anticancer Activity in Mice with Metastatic Colon Cancer, Ovarian Cancer and Renal Cell Carcinoma.

Sulfur-containing amino acids methionine (Met), cysteine (Cys) and taurine (Tau) are common dietary constituents with important cellular roles. Met restriction is already known to exert in vivo anticancer activity. However, since Met is a precursor of Cys and Cys produces Tau, the role of Cys and Tau in the anticancer activity of Met-restricted diets is poorly understood. In this work, we screened the in vivo anticancer activity of several Met-deficient artificial diets supplemented with Cys, Tau or both. Diet B1 (6% casein, 2.5% leucine, 0.2% Cys and 1% lipids) and diet B2B (6% casein, 5% glutamine, 2.5% leucine, 0.2% Tau and 1% lipids) showed the highest activity and were selected for further studies. Both diets induced marked anticancer activity in two animal models of metastatic colon cancer, which were established by injecting CT26.WT murine colon cancer cells in the tail vein or peritoneum of immunocompetent BALB/cAnNRj mice. Diets B1 and B2B also increased survival of mice with disseminated ovarian cancer (intraperitoneal ID8 Tp53-/- cells in C57BL/6JRj mice) and renal cell carcinoma (intraperitoneal Renca cells in BALB/cAnNRj mice). The high activity of diet B1 in mice with metastatic colon cancer may be useful in colon cancer therapy.

Artificial Diets with Selective Restriction of Amino Acids and Very Low Levels of Lipids Induce Anticancer Activity in Mice with Metastatic Triple-Negative Breast Cancer.

Patients with metastatic triple negative breast cancer (TNBC) need new therapies to improve the low survival rates achieved with standard treatments. In this work, we show for the first time that the survival of mice with metastatic TNBC can be markedly increased by replacing their normal diet with artificial diets in which the levels of amino acids (AAs) and lipids are strongly manipulated. After observing selective anticancer activity in vitro, we prepared five artificial diets and evaluated their anticancer activity in a challenging model of metastatic TNBC. The model was established by injecting 4T1 murine TNBC cells into the tail vein of immunocompetent BALB/cAnNRj mice. First-line drugs doxorubicin and capecitabine were also tested in this model. AA manipulation led to modest improvements in mice survival when the levels of lipids were normal. Reducing lipid levels to 1% markedly improved the activity of several diets with different AA content. Some mice fed the artificial diets as monotherapy lived much longer than mice treated with doxorubicin and capecitabine. An artificial diet without 10 non-essential AAs, with reduced levels of essential AAs, and with 1% lipids improved the survival not only of mice with TNBC but also of mice with other types of metastatic cancers.

Manipulation of Amino Acid Levels with Artificial Diets Induces a Marked Anticancer Activity in Mice with Renal Cell Carcinoma.

Targeted therapies with antiangiogenic drugs (e.g., sunitinib) and immune checkpoint inhibitors (e.g., anti-PD-1 antibodies) are the standard of care for patients with metastatic renal cell carcinoma. Although these treatments improve patient survival, they are rarely curative. We previously hypothesized that advanced cancers might be treated without drugs by using artificial diets in which the levels of specific amino acids (AAs) are manipulated. In this work, after showing that AA manipulation induces selective anticancer activity in renal cell carcinoma cells in vitro, we screened 18 artificial diets for anticancer activity in a challenging animal model of renal cell carcinoma. The model was established by injecting murine renal cell carcinoma (Renca) cells into the peritoneum of immunocompetent BALB/cAnNRj mice. Mice survival was markedly improved when their normal diet was replaced with our artificial diets. Mice fed a diet lacking six AAs (diet T2) lived longer than mice treated with sunitinib or anti-PD-1 immunotherapy; several animals lived very long or were cured. Controlling the levels of several AAs (e.g., cysteine, methionine, and leucine) and lipids was important for the anticancer activity of the diets. Additional studies are needed to further evaluate the therapeutic potential and mechanism of action of this simple and inexpensive anticancer strategy.

Artificial Diets Based on Selective Amino Acid Restriction versus Capecitabine in Mice with Metastatic Colon Cancer.

New therapies are needed to improve the low survival rates of patients with metastatic colon cancer. Evidence suggests that amino acid (AA) restriction can be used to target the altered metabolism of cancer cells. In this work, we evaluated the therapeutic potential of selective AA restriction in colon cancer. After observing anticancer activity in vitro, we prepared several artificial diets and evaluated their anticancer activity in two challenging animal models of metastatic colon cancer. These models were established by injecting CT26.WT murine colon cancer cells in the peritoneum (peritoneal dissemination) or in the tail vein (pulmonary metastases) of immunocompetent BALB/cAnNRj mice. Capecitabine, which is a first-line treatment for patients with metastatic colon cancer, was also evaluated in these models. Mice fed diet TC1 (a diet lacking 10 AAs) and diet TC5 (a diet with 6% casein, 5% glutamine, and 2.5% leucine) lived longer than untreated mice in both models; several mice survived the treatment. Diet TC5 was better than several cycles of capecitabine in both cancer models. Cysteine supplementation blocked the activity of diets TC1 and TC5, but cysteine restriction was not sufficient for activity. Our results indicated that artificial diets based on selective AA restriction have therapeutic potential for colon cancer.

Screening for Selective Anticancer Activity of 65 Extracts of Plants Collected in Western Andalusia, Spain.

Finding cytotoxic drugs with a high selectivity towards cancer cells is crucial to improve the low survival rates of patients diagnosed with metastatic cancers. Since plants are an important source of anticancer drugs, we have screened 65 extracts from 45 plants collected in several areas of Western Andalusia (Spain) for cytotoxic activity on lung cancer cells versus lung normal cells. An extract from the leaves of Tetraclinis articulata (Vahl) Mast. (Cupressaceae) showed a marked cytotoxicity (IC50 = 0.37 ± 0.03 µg/mL) and selectivity (selectivity index = 378.3) against the lung cancer cells; cisplatin, 5-fluorouracil, and an extract from the leaves of Taxus baccata L. (Taxaceae) were less cytotoxic and selective. Extracts from Cascabela thevetia (L.) Lippold (Apocynaceae), Frangula alnus Mill. (Rhamnaceae), Iberis ciliata subsp. contracta (Pers.) Moreno (Brassicaceae), Juniperus macrocarpa Sm (Cupressaceae), and Pancratium maritimum L. (Amaryllidaceae) also showed selective cytotoxicity (selectivity index > 10). Active extracts were also tested against a panel of cancer cell lines from a variety tissues. The plants identified in this work are potential sources of natural compounds with selective toxicity towards cancer cells.

Screening for selective anticancer activity of plants from Grazalema Natural Park, Spain.

Since plants are an important source of anticancer drugs, we have carried out a random screening for selective anticancer activity of 57 extracts from 45 plants collected in Grazalema Natural Park, an area in the South of Spain of high plant diversity and endemism. Using lung cancer cells (A549) and lung non-malignant cells (MRC-5), we found that several extracts were more cytotoxic and selective against the cancer cells than the standard anticancer agent cisplatin. Five active extracts were further tested in cancer and normal cell lines from other tissues, including three skin cell lines with increasing degree of malignancy. An extract from the leaves of Daphne laureola L. (Thymelaeaceae) showed a striking potency and selectivity on lung cancer cells and leukemia cells; the IC50 values against these cancer cells were approximately 10,000-fold lower than against the normal cells. Daphnane-type diterpene orthoesters may be responsible for this highly selective anticancer activity.

A 30-s exposure to ethanol 20% is cytotoxic to human keratinocytes: possible mechanistic link between alcohol-containing mouthwashes and oral cancer.

OBJECTIVES: To provide mechanistic evidence for the epidemiological link between long-term use of alcohol-containing mouthwashes and oral cancer. MATERIAL AND METHODS: Human epithelial keratinocytes were exposed for 30 s to concentrations of ethanol commonly present in mouthwashes. After a recovery period, cell viability was assessed with the MTT assay. RESULTS: A marked cytotoxic effect was observed for ethanol concentrations of 20% and above. CONCLUSIONS: The cytotoxicity of ethanol may explain the epidemiological association between mouthwash use and oral cancer. Evidence suggests that the risk of developing cancer in a tissue is strongly determined by the number of stem cell divisions accumulated by the tissue during a person's lifetime; cell division is a major source of mutations and other cancer-promoting errors. Since cell death activates the division of stem cells, the possible cytotoxicity of ethanol on the cells lining the oral mucosa will promote the division of the stem cells located in deeper layers to produce new cells to regenerate the damaged epithelium. If we regularly use mouthwashes containing cytotoxic concentrations of ethanol, the stem cells of the oral cavity may need to divide more often than usual and our risk of developing oral cancer may increase. CLINICAL RELEVANCE: Many mouthwashes contain percentages of ethanol above 20%. Because ethanol is not crucial to prevent and reduce gingivitis and plaque, members of the dental team should consider the potential risk of oral cancer associated with frequent use of alcohol-containing mouthwashes when advising their patients.

Avoiding the ingestion of cytotoxic concentrations of ethanol may reduce the risk of cancer associated with alcohol consumption.

Alcohol consumption is a known risk factor for cancer. Almost 6% of all cancers worldwide are attributable to alcohol use. Approximately half of them occur in tissues highly exposed to ethanol, such as the oral cavity, pharynx, upper larynx and esophagus. However, since ethanol is not mutagenic and the mutagenic metabolite of ethanol (acetaldehyde) is mainly produced in the liver, it is unclear why alcohol consumption preferentially exerts a local carcinogenic effect. Recent findings indicate that the risk of cancer in a tissue is strongly correlated with the number of stem cell divisions accumulated by the tissue; the accumulation of stem cell divisions leads to the accumulation of cancer-promoting errors such as mutations occurring during DNA replication. Since cell death activates the division of stem cells, we recently proposed that the possible cytotoxicity of ethanol on the cells lining the tissues in direct contact with alcoholic beverages could explain the local carcinogenic effect of alcohol. Here we report that short-term exposures (2-3 s) to ethanol concentrations between 10% and 15% start to cause a marked cytotoxic effect on human epithelial keratinocytes in a concentration-dependent manner. We propose that choosing alcoholic beverages containing non-cytotoxic concentrations of ethanol, or diluting ethanol to non-cytotoxic concentrations, may be a simple and effective way to reduce the risk of cancers of the oral cavity, pharynx, larynx and esophagus in alcohol users. This preventive strategy may also reduce the known synergistic effect of alcohol drinking and tobacco smoking on the risk of these cancers.

Cells Deficient in the Fanconi Anemia Protein FANCD2 are Hypersensitive to the Cytotoxicity and DNA Damage Induced by Coffee and Caffeic Acid.

Epidemiological studies have found a positive association between coffee consumption and a lower risk of cardiovascular disorders, some cancers, diabetes, Parkinson and Alzheimer disease. Coffee consumption, however, has also been linked to an increased risk of developing some types of cancer, including bladder cancer in adults and leukemia in children of mothers who drink coffee during pregnancy. Since cancer is driven by the accumulation of DNA alterations, the ability of the coffee constituent caffeic acid to induce DNA damage in cells may play a role in the carcinogenic potential of this beverage. This carcinogenic potential may be exacerbated in cells with DNA repair defects. People with the genetic disease Fanconi Anemia have DNA repair deficiencies and are predisposed to several cancers, particularly acute myeloid leukemia. Defects in the DNA repair protein Fanconi Anemia D2 (FANCD2) also play an important role in the development of a variety of cancers (e.g., bladder cancer) in people without this genetic disease. This communication shows that cells deficient in FANCD2 are hypersensitive to the cytotoxicity (clonogenic assay) and DNA damage (γ-H2AX and 53BP1 focus assay) induced by caffeic acid and by a commercial lyophilized coffee extract. These data suggest that people with Fanconi Anemia, or healthy people who develop sporadic mutations in FANCD2, may be hypersensitive to the carcinogenic activity of coffee.