Clinical Cancer Drugs - Volume 7, Issue 2, 2020

Although there are no 100% successful methods for treating cancer, chemotherapy is still one of the most commonly used approaches in its management. One of the most significant problems in cancer treatment is the resistance of cancer cells to chemotherapeutic agents. This review aims to unveil the factors contributing to this problem originally beginning with fundamental units like biomarkers and microRNAs. As more studies and researches carried out, various levels of miRNA expression were found among normal and cancer cells. Overexpression of oncomir and downregulation of tumour-suppressor miRNAs can lead to the emergence of cancer. Data collected from studying these miRNAs can help in the diagnosis, prognosis and developing therapies, which will assist in overcoming the emerged resistance.

Background: Regulation of protein phosphatase 2A (PP2A) plays an important role in hematologic and solid neoplasms. Therefore, the use of sphingosine analogs as anti-neoplastic drugs has shown potential due to their role as PP2A activators. Objective: Investigation of whether sphingosine analogs bind to endogenous inhibitor proteins of PP2A, such as I2 ^PP2A/SET and/or CIP2A, and whether this binding reactivates PP2A, allowing it to resume its role as a tumor suppressor. Methods: Literature from the PubMed database was searched and those articles related to PP2A and sphingosine analogs were reviewed. Results: Utilization of sphingosine analogs in hematologic and solid neoplasms revealed numerous mechanisms of inducing cell death. Regulation of PP2A through modulation of I2 PP2A/SET and/or CIP2A was demonstrated in a variety of neoplastic processes; however, unique mechanisms such as cell necrosis via the production of reactive oxygen species was also appreciated. Conclusion: Only certain malignancies expressed endogenous inhibitor proteins, yet sphingosine analogs were able to induce cell death in neoplasms that did not express these proteins. This suggests that sphingosine analogs may be utilized for anti-neoplastic therapy via reactivation of PP2A however, it is not the exclusive mechanism for inducing cell death. Further investigation of sphingosine analogs as a novel or adjunctive chemotherapeutic treatment is warranted.

The COVID-19 pandemic has caused millions of infections and hundreds of thousands deaths in the world. The pandemic is still ongoing and no specific antivirals have been found to control COVID-19. The integration of Traditional Chinese Medicine with supportive measures of Modern Medicine has reportedly played an important role in the control of COVID-19 in China. This review summarizes the evidence of TCM in the treatment of COVID-19 and discusses the plausible mechanism of TCM in control of COVID-19 and other viral infectious diseases.

In the last four decades, the emphasis was laid on the research of small organic molecules with potential anti-cancer activity. Linezolid was the first oxazolidinone derivative approved by FDA for MRSA treatment. Despite its major role in antimicrobial activity, these molecules display other properties, also serving as an antitumor agent. The importance of drug repurposing could be highlighted by the use of Oxazolidinone derivatives in pre-clinical studies, which are able to act through different pathways, such as partial agonist of transcription factor PPAR-γ, an inhibitor of key enzymes related to hormone-dependent disorders and even on sphingolipid metabolism as well. The purpose of this short review is to discuss the application of oxazolidinone derivatives as an antitumor agent by highlighting the most promising molecules studied by many research groups worldwide. Main biological activity against several tumor cell lines, including hematopoietic and solid cancer cell lines have been discussed. In addition, this study intends to report how different types of oxazolidinone derivatives can act as antitumor agents describing their distinct mechanisms of action based on their targets.

Background: Statistical methods commonly used in survival analysis typically provide the probability that the difference between groups is due to chance, but do not offer a reliable estimate of the average survival time difference between groups (the difference between median survival time is usually reported). Objective: We suggest a Maximum-Entropy estimator for the average Survival Time Difference (MESTD) between groups. Methods: The estimator is based on the extra survival time, which should be added to each member of the group, to produce the maximum entropy of the result (resulting in the groups becoming most similar). The estimator is calculated only from time to event data, does not necessarily assume hazard proportionality and provides the magnitude of the clinical differences between the groups. Results: Monte Carlo simulations show that, even at low sample numbers (much lower than the ones needed to prove that the two groups are statistically different), the MESTD estimator is a reliable predictor of the clinical differences between the groups, and therefore can be used to estimate from (low sample numbers) preliminary data whether or not the large sample number experiment is worth pursuing. Conclusion: By providing a reasonable estimate for the efficacy of a treatment (e.g., for cancer) even for low sample data, it might provide useful insight in testing new methods for treatment (for example, for quick testing of multiple combinations of cancer drugs).

Background: The goal of this study was to evaluate the anticancer and testosteroneinhibitory effects of 2‘-{[(E) androst-5-en-17-ylidene]methyl}-4‘,5‘-dihydro-1‘,3‘-oxazole-3β-oleate (Alsevirone-NF). Materials and Methods: PC-3, DU-145, LnCap and 22rv1 prostate cancer cell lines were used for MTT assay. 22rv1 subcutaneous cancer xenografts in Balb/c nude mice were used for in vivo efficacy experiments. Testosterone level was determined after repeated administration of Abiraterone 20, 100 or 200 mg/kg vs Alsevirone-NF 5, 25 or 50 mg/kg daily for 14 days. Results: Alsevirone-NF induced more significant cytotoxicity against PC3, 22rv1 and DU-145 cell lines compared to Abiraterone or Alsevirone-treated control: IC50 7.1 vs 20.6 vs 29.1 μg/ml, 7.7 vs 20.0 vs 12.7 μg/ml, 3.8 vs 43.4 vs 8.5 μg/ml, respectively. IC50 in LnCap cells was almost equal for all three studied agents, 29.2 vs 26.2 vs 30.2 μg/ml for Abiraterone, Alsevirone and Alsevirone-NF. In gonadectomized mice, significant reduction of testosterone level was observed in mice receiving Alsevirone-NF in a maximum single dose of 50 mg/kg (cumulative dose 700 mg/kg): 0.2 nmol/l vs 0.57 nmol/l in control group and 0.83 nmol/l in Abiraterone group, single dose 100 mg/kg. Statistically significant anticancer effect in vivo was obtained on day 11 after the start of treatment: Abiraterone T/C = 27% (p<0.05), Alsevirone-NF single dose 1200 mg/kg Т/С = 45% (p<0.05). Conclusion: Alsevirone-NF exhibited higher cytotoxic activity, comparable anticancer effect in 22rv1-bearing Balb/c nude mice and provided a more significant reduction of testosterone level in gonadectomized mice in direct comparison against Abiraterone.

Background: The failure of imatinib therapy in patients with chronic myeloid leukemia (CML) is associated with the presence of leukemic stem cell (LSC), and the altered LSC level was reported to occur earlier in the progression of CML. Objective: The study aimed to assess the association between the level of LSC and treatment response among CML patients treated with imatinib mesylate. Methods: A cross-sectional study was conducted in Saiful Anwar Hospital. All participants were divided into two groups, response and non-response group. To assess the level of LSC, flow cytometry was conducted conforming with BD Bioscience. The association and effect estimates were determined using multiple logistic regression. Results and Discussion: A total of 29 response and non-response CML patients treated with imatinib therapy were recruited for our study. After six months of imatinib therapy, we found that elevated levels of leukocytes, thrombocytes, basophils, and blast cells were associated with treatment failure among CML patients treated with imatinib. Moreover, we also found that the LSC level was observed significantly higher in the non-response group compared to the response group among CML patients treated with imatinib. Conclusion: Our study reveals that the elevated level of LSC is considered as an important factor to predict the failure of imatinib therapy among CML patients.

Background/Objective: With the increasing interest in natural products, a phase I openlabel study of OMN54 (Aneustat™) in patients with advanced malignancies was initiated to determine toxicity, maximum tolerated dose (MTD), dose limiting toxicities (DLT), and pharmacokinetics (PK). OMN54 is a multitargeted agent, combining three Chinese botanicals; Ganoderma lucidium, Salvia miltiorrhiza and Scutellaria barbata. Methods: Eligible patients (pts) were >18 years of age with advanced solid tumors, able to swallow oral capsules, ECOG performance status < 2, measurable disease as defined by RECIST 1.1 and adequate organ function. Results: Twenty-two patients were enrolled in 6 dose levels, 2 with daily dosing and 4 with twicedaily dosing ranging from 1 to 5 grams daily. All were evaluated for toxicity and 20 for response. No treatment-related dose-limiting toxicities (DLTs) were reported and the recommended phase II dose (RP2D) was determined to be 2.5 g twice daily. Seven adverse events in 5 patients were reported as possibly drug-related; 6 were GI toxicity and 1 was a skin disorder. All were grade 1 except one grade 2 vomiting. No RECIST responses were seen. Six pts were treated with > 2 cycles; one for 8 cycles. Four patients had reductions in TGF –β and EGF, exploratory biomarkers possibly suggestive of a drug effect. Plasma half-lives of 1 -2 hours were noted for all parent drug chemical markers with no accumulation over time. Conclusion: OMN54 was well tolerated, with no DLTs observed. Further studies at the RP2D will assess the biological activity.