Biological Screening and Radiolabeling of Raptinal as a Potential Anticancer Novel Drug in Hepatocellular Carcinoma Model

The small molecule raptinal can simultaneously induce apoptosis and inhibit PANX1 activity

Discovery of new small molecules that can activate distinct programmed cell death pathway is of significant interest as a research tool and for the development of novel therapeutics for pathological conditions such as cancer and infectious diseases. The small molecule raptinal was discovered as a pro-apoptotic compound that can rapidly trigger apoptosis by promoting the release of cytochrome c from the mitochondria and subsequently activating the intrinsic apoptotic pathway. As raptinal is very effective at inducing apoptosis in a variety of different cell types in vitro and in vivo, it has been used in many studies investigating cell death as well as the clearance of dying cells. While examining raptinal as an apoptosis inducer, we unexpectedly identified that in addition to its pro-apoptotic activities, raptinal can also inhibit the activity of caspase-activated Pannexin 1 (PANX1), a ubiquitously expressed transmembrane channel that regulates many cell death-associated processes. By implementing numerous biochemical, cell biological and electrophysiological approaches, we discovered that raptinal can simultaneously induce apoptosis and inhibit PANX1 activity. Surprisingly, raptinal was found to inhibit cleavage-activated PANX1 via a mechanism distinct to other well-described PANX1 inhibitors such as carbenoxolone and trovafloxacin. Furthermore, raptinal also interfered with PANX1-regulated apoptotic processes including the release of the 'find-me' signal ATP, the formation of apoptotic cell-derived extracellular vesicles, as well as NLRP3 inflammasome activation. Taken together, these data identify raptinal as the first compound that can simultaneously induce apoptosis and inhibit PANX1 channels. This has broad implications for the use of raptinal in cell death studies as well as in the development new PANX1 inhibitors.

New phenothiazine conjugates as apoptosis inducing agents: Design, synthesis, In-vitro anti-cancer screening and 131I-radiolabeling for in-vivo evaluation

Phenothiazines (PTZs) are a group of compounds characterized by the presence of the 10H-dibenzo-[b,e]-1,4-thiazine system. PTZs used in clinics as antipsychotic drugs with other diverse biological activities. The current aim of the study is to investigate and understand the effect of potent PTZs compounds using a group of In-vitro and In-vivo assays. A total of seventeen novel phenothiazine derivatives have been designed, synthesized, and evaluated primarily in-vitro for their ability to inhibit proliferation activity against NCI-60 cancer cell lines, including several multi-drug resistant (MDR) tumor cell lines. Almost all compounds were active and displayed promising cellular activities with GI50 values in the sub-micromolar range. Four of the most promising derivatives (4b, 4h, 4g and 6e) have been further tested against two selected sensitive cancer cell lines (colon cancer; HCT-116 and breast cancer; MDA-MB231). The apoptosis assay showed that all the selected compounds were able to induce early apoptosis and compound 6e was able to induce additional cellular necrosis. Cell cycle assay showed all selected compounds were able to induce cell cycle arrest at sub-molecular phase of G0-G1 with compound 6e induced cell cycle arrest at G2M in HCT-116 cells. Accordingly, the apoptotic effect of the selected compounds was extensively investigated on genetic level and Casp-3, Casp-9 and Bax gene were up-regulated with down-regulation of Bcl-2 gene suggesting the activation of both intrinsic and extrinsic pathways. In-vivo evaluation of the antitumor activity of compound 4b in solid tumor bearing mice showed promising therapeutic effect with manifestation of dose and time dependent toxic effects at higher doses. For better evaluation of the degree of localization of 4b, its 131I-congener (131I-4b) was injected intravenously in Ehrlich solid tumor bearing mice that showed good localization at tumor site with rapid distribution and clearance from the blood. In-silico study suggested NADPH oxidases (NOXs) as potential molecular target. The compounds introduced in the current study work provided a cutting-edge phenothiazine hybrid scaffold with promising anti-proliferation action that may suggest their anti-cancer activity.

Growth Inhibition and Apoptotic Effect of Pine Extract and Abietic Acid on MCF-7 Breast Cancer Cells via Alteration of Multiple Gene Expressions Using In Vitro Approach

In vitro anti-proliferative activity of Pinus palustris extract and its purified abietic acid was assessed against different human cancer cell lines (HepG-2, MCF-7 and HCT-116) compared to normal WI-38 cell line. Abietic acid showed more promising IC50 values against MCF-7 cells than pine extract (0.06 µg/mL and 0.11 µM, respectively), with insignificant cytotoxicity toward normal fibroblast WI-38 cells. Abietic acid triggered both G2/M cell arrest and subG0-G1 subpopulation in MCF-7, compared to SubG0-G1 subpopulation arrest only for the extract. It also induced overexpression of key apoptotic genes (Fas, FasL, Casp3, Casp8, Cyt-C and Bax) and downregulation of both proliferation (VEGF, IGFR1, TGF-β) and oncogenic (C-myc and NF-κB) genes. Additionally, abietic acid induced overexpression of cytochrome-C protein. Furthermore, it increased levels of total antioxidants to diminish carcinogenesis and chemotherapy resistance. P. palustris is a valuable source of active abietic acid, an antiproliferative agent to MCF-7 cells through induction of apoptosis with promising future anticancer agency in breast cancer therapy.

Targeting the Interplay between Cancer Metabolic Reprogramming and Cell Death Pathways as a Viable Therapeutic Path

In cancer cells, metabolic adaptations are often observed in terms of nutrient absorption, biosynthesis of macromolecules, and production of energy necessary to meet the needs of the tumor cell such as uncontrolled proliferation, dissemination, and acquisition of resistance to death processes induced by both unfavorable environmental conditions and therapeutic drugs. Many oncogenes and tumor suppressor genes have a significant effect on cellular metabolism, as there is a close relationship between the pathways activated by these genes and the various metabolic options. The metabolic adaptations observed in cancer cells not only promote their proliferation and invasion, but also their survival by inducing intrinsic and acquired resistance to various anticancer agents and to various forms of cell death, such as apoptosis, necroptosis, autophagy, and ferroptosis. In this review we analyze the main metabolic differences between cancer and non-cancer cells and how these can affect the various cell death pathways, effectively determining the susceptibility of cancer cells to therapy-induced death. Targeting the metabolic peculiarities of cancer could represent in the near future an innovative therapeutic strategy for the treatment of those tumors whose metabolic characteristics are known.

Green tea essential oil encapsulated chitosan nanoparticles-based radiopharmaceutical as a new trend for solid tumor theranosis

The existing study is embarked on investigating the antineoplastic activity of green tea essential oil (GTO) as a natural product. In this regard, GTO was encapsulated in cationic chitosan, nitrogenous-polysaccharide derived by partial deacetylation of chitin, nanoparticles (CS NPs) with entrapment efficiency (EE%) of 81.4 ± 5.7% and a mean particle-size of 30.7 ± 1.13 nm. Moreover, the cytotoxic effect of CS/GTO NPs was evaluated versus human liver (HepG-2), breast (MCF-7) and colon (HCT-116) cancer cell-lines and exhibited a positive impact when compared to bare CS NPs by 3, 2.3 and 1.7 fold for the three cell lines, respectively. More interestingly, CS/GTO NPs were complexed with technethium-99m (^99mTc) radionuclide. With a view to achieve a successful radiolabeling process, different parameters were optimized resulting in a radiolabeling efficiency (RE%) of 93.4 ± 1.2%. Radiopharmacokinetics of the radiolabeled NPs in healthy mice demonstrated a reticuloendothelial system (RES) evading and long blood circulation time up to 4 h. On the other hand, the biodistribution profile in solid tumor models showed 20.3 ± 2.1% localization and cancer cell targeting within just 30 min. On the whole, the reported results encourage the potential use of CS/GTO NPs as a side effect-free anticancer agent and its ^99mTc-analogue as a novel CS/GTO NPs-based diagnostic-radiopharmaceutical for cancer.