Chemical screening identifies novel small molecule activators of natural killer cell cytotoxicity against cancer cells

Identification of Natural Killer Cell Enhancers Through Mimicking of the Tumor Microenvironment

The tumor microenvironment (TME) is a pro-cancerous niche harboring immunosuppressive factors that are secreted by cancer cells and the surrounding cancer-supportive tissue, such as kynurenine, prostaglandin E2 and transforming growth factor β (TGFβ). These factors dampen the activity of cytotoxic lymphocytes like natural killer (NK) cells, allowing evasion of immune cell-mediated killing. To identify small molecules that counteract the immunosuppressive effect of the TME and restore NK cell-mediated cytotoxicity, we developed a phenotypic co-culture assay of cancer cells and primary lymphocytes suitable for medium-throughput screening. We discovered small molecules that restore NK cell-mediated cytotoxicity through diverse mechanisms. The potent TGFβ type I receptor (TGFβR-1) inhibitor, RepSox, stood out as superior to other TGFβR-1 inhibitors due to its ability to abolish the effects of both inhibitory factors used in our setup. This mode of action goes beyond TGFβR-1 inhibition and is related to the simultaneous abrogation of cyclooxygenase 1 (COX1) activity.

Exploring the potential of bis(thiazol-5-yl)phenylmethane derivatives as novel candidates against genetically defined multidrug-resistant Staphylococcus aureus

Antimicrobial resistance (AMR) represents an alarming global challenge to public health. Infections caused by multidrug-resistant Staphylococcus aureus (S. aureus) pose an emerging global threat. Therefore, it is crucial to develop novel compounds with promising antimicrobial activity against S. aureus especially those with challenging resistance mechanisms and biofilm formation. Series of bis(thiazol-5-yl)phenylmethane derivatives were evaluated against drug-resistant Gram-positive bacteria. The screening revealed an S. aureus-selective mechanism of bis(thiazol-5-yl)phenylmethane derivatives (MIC 2-64 μg/mL), while significantly lower activity was observed with vancomycin-resistant Enterococcus faecalis (MIC 64 μg/mL) (p<0.05). The most active phenylmethane-based (p-tolyl) derivative, 23a, containing nitro and dimethylamine substituents, and the naphthalene-based derivative, 28b, harboring fluorine and nitro substituents, exhibited strong, near MIC bactericidal activity against S. aureus with genetically defined resistance phenotypes such as MSSA, MRSA, and VRSA and their biofilms. The in silico modeling revealed that most promising compounds 23a and 28b were predicted to bind S. aureus MurC ligase. The 23a and 28b formed bonds with MurC residues at binding site, specifically Ser12 and Arg375, indicating consequential interactions essential for complex stability. The in vitro antimicrobial activity of compound 28b was not affected by the addition of 50% serum. Finally, all tested bis(thiazol-5-yl)phenylmethane derivatives showed favorable cytotoxicity profiles in A549 and THP-1-derived macrophage models. These results demonstrated that bis(thiazol-5-yl)phenylmethane derivatives 23a and 28b could be potentially explored as scaffolds for the development of novel candidates targeting drug-resistant S. aureus. Further studies are also warranted to understand in vivo safety, efficacy, and pharmacological bioavailability of bis(thiazol-5-yl)phenylmethane derivatives.

Polymeric biomaterial-inspired cell surface modulation for the development of novel anticancer therapeutics

Immune cell-based therapies are a rapidly emerging class of new medicines that directly treat and prevent targeted cancer. However multiple biological barriers impede the activity of live immune cells, and therefore necessitate the use of surface-modified immune cells for cancer prevention. Synthetic and/or natural biomaterials represent the leading approach for immune cell surface modulation. Different types of biomaterials can be applied to cell surface membranes through hydrophobic insertion, layer-by-layer attachment, and covalent conjugations to acquire surface modification in mammalian cells. These biomaterials generate reciprocity to enable cell-cell interactions. In this review, we highlight the different biomaterials (lipidic and polymeric)-based advanced applications for cell-surface modulation, a few cell recognition moieties, and how their interplay in cell-cell interaction. We discuss the cancer-killing efficacy of NK cells, followed by their surface engineering for cancer treatment. Ultimately, this review connects biomaterials and biologically active NK cells that play key roles in cancer immunotherapy applications.

Atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage small cell lung cancer: a real-life data of the Turkish Oncology Group

PURPOSE

Atezolizumab has been shown to be effective and safe in randomized trial in the first-line treatment of extensive-stage small cell lung cancer (SCLC). However, there are limited real-life data on atezolizumab. In this study, we aimed to determine the real-life efficacy and safety of atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage SCLC.

METHODS

This trial is a retrospective multicenter study of the Turkish Oncology Group, which included extensive-stage SCLC patients who received atezolizumab combined with chemotherapy in a first-line treatment. The characteristics of the patients, treatment and response rates, and PFS and OS are presented. Factors associated with PFS and OS were analyzed by univariate and multivariate analysis.

RESULTS

A total of 213 patients at the 30 oncology centers were included. The median number of chemotherapy cycle was 5 (1-8) and atezolizumab cycle was 7 (1-32). After median 11.9 months of follow-up, median PFS and OS was 6.8 months (95%CI 5.7-7.8), and 11.9 months (95%CI 11-12.7), respectively. The ORR was 61.9%. ECOG-PS (p = 0.002) and number of metastatic sites (p = 0.001) were associated with PFS and pack-year of smoking (p = 0.05), while ECOG-PS (p = 0.03) and number of metastatic sites (p = 0.001) were associated with OS. Hematological side effects were common and toxicities were manageable.

CONCLUSION

This real-life data confirm the efficacy and safety of atezolizumab in combination with chemotherapy in first-line treatment of extensive-stage SCLC.