Preclinical models of breast cancer: Two-way shuttles for immune checkpoint inhibitors from and to patient bedside

Advances in acute myeloid leukemia differentiation therapy: A critical review

Acute myeloid leukemia (AML) is characterized by impaired differentiation and indefinite proliferation of abnormal myeloid progenitors. Although differentiating agents were deemed to revolutionize AML therapy, most treated non-APL AML patients are refractory or relapse. According to cancer stem cell model, leukemia-initiating cells are the root cause of relapse given their unidirectional potential to generate differentiated AML blasts. Nonetheless, accumulating evidences emphasize the de-differentiation plasticity and leukemogenic potential of mature AML blasts and the frailty of targeting leukemic stem cells per se. This review critically discusses the potential and challenges of (lessons learnt from) conventional and novel differentiating agents in AML therapy. Although differentiating agents might hold promise, they should be exploited within the context of a rationale combination regimen eradicating all maturation/differentiation states of AML cells. The results of the routinely used immunophenotypic markers and/or morphological analyses of differentiation should be carefully interpreted given their propensity to underestimate AML burden.

Targeting Breast Cancer: The Familiar, the Emerging, and the Uncharted Territories

Breast cancer became the most diagnosed cancer in the world in 2020. Chemotherapy is still the leading clinical strategy in breast cancer treatment, followed by hormone therapy (mostly used in hormone receptor-positive types). However, with our ever-expanding knowledge of signaling pathways in cancer biology, new molecular targets are identified for potential novel molecularly targeted drugs in breast cancer treatment. While this has resulted in the approval of a few molecularly targeted drugs by the FDA (including drugs targeting immune checkpoints), a wide array of signaling pathways seem to be still underexplored. Also, while combinatorial treatments have become common practice in clinics, the majority of these approaches seem to combine molecularly targeted drugs with chemotherapeutic agents. In this manuscript, we start by analyzing the list of FDA-approved molecularly targeted drugs for breast cancer to evaluate where molecular targeting stands in breast cancer treatment today. We will then provide an overview of other options currently under clinical trial or being investigated in pre-clinical studies.

Preclinical activity of fluvastatin-loaded self-nanoemulsifying delivery system against breast cancer models: Emphasis on apoptosis

Statins trigger apoptotic cell death in some types of growing tumor cells in a cholesterol-lowering-independent manner. Self-nanoemulsifying delivery systems (SNEDs) are potentially effective for the suppression of breast cancer development. This study aims to investigate the potential anticancer activity of fluvastatin (FLV)-SNEDs in breast cancer while comparing it with FLV in vitro as well as in vivo exploiting/using MDA-MB-231 and Erhlich ascites carcinoma (EAC)-bearing mice, respectively. Biochemical analysis of liver and kidney functions, oxidative stress markers, and histopathological examinations of such tumor tissues were performed showing the potentiality of SNEDs as a nanocarrier for antitumor agents. FLV-SNEDs demonstrated more potent anticancer activity compared to FLV on MDA-MB-231 and hepatocellular carcinoma (HepG2) cells. In vivo experiments on the EAC-bearing mice model indicated that FLV and-to a greater extent-FLV-SNEDs ameliorated EAC-induced hepatotoxicity and nephrotoxicity. FLV or FLV-SNEDs evidently reduced the percent of Ki-67 +ve EAC cells by 57.5% and 86.5% in comparison to the vehicle-treated EAC group. In addition, FLV or FLV-SNEDs decreased Bcl-2 levels in serum and liver specimens. In contrast, FLV or FLV-SNEDs significantly activated the executioner caspase-3. Simultaneously, both FLV and FLV-SNEDs stimulated p53 signaling and modulated Bcl-2 protein levels in treated cells. Collectively, these results support the contribution of apoptotic cell death in mediating the anticancer activities of FLV and FLV-SNEDs against murine EAC model in vivo. This study provides new understandings of how FLV and FLV-SNEDs regulate EAC cell viability via upregulation of p53 signaling, and through modulation of cleaved caspase-3 as well as antiapoptotic Bcl-2 marker.

Glutathione-sensitive IPI-549 nanoparticles synergized with photodynamic Chlorin e6 for the treatment of breast cancer

We combined phosphoinositol-3-kinin inhibitor IPI-549 and photodynamic Chlorin e6 (Ce6) on carboxymethyl chitosan to develop a novel drug delivery nanoparticle (NP) system (Ce6/CMCS-DSP-IPI549) and evaluate its glutathione (GSH) sensitivity and targeting ability for breast cancer treatment. The NPs were spherical with a uniform size of 218.8 nm, a stable structure over 7 days. The maximum encapsulation efficiency was 64.42%, and NPs drug loading was 8.05%. The NPs released drugs within tumor cells due to their high GSH concentration, while they maintained structural integrity in normal cells, which have low GSH concentration. The cumulative release rates of IPI-549 and Ce6 at 108 h were 70.67% and 40.35% (at GSH 10 mM) and 8.11% and 2.71% (at GSH 2μM), respectively. The NPs showed a strong inhibitory effect on 4T1 cells yet did not affect human umbilical vein endothelial cells (HUVECs). After irradiation by a 660 nm infrared laser for 72 h, the survival rate of 4T1 cells was 15.51%. Cellular uptake studies indicated that the NPs could accurately release drugs into tumor cells. In addition, the NPs had a good photodynamic effect and promoted the release of reactive oxygen species to damage tumor cells. Overall, the combination therapy of IPI-549 and Ce6 is safe and effective, and may provide a new avenue for the treatment of breast cancer.

Dendritic cell vaccine immunotherapy; the beginning of the end of cancer and COVID-19. A hypothesis

Immunotherapy is the newest approach to combat cancer. It can be achieved using several strategies, among which is the dendritic cell (DC) vaccine therapy. Several clinical trials are ongoing using DC vaccine therapy either as a sole agent or in combination with other interventions to tackle different types of cancer. Immunotherapy can offer a potential treatment to coronavirus disease 2019 (COVID-19) the worst pandemic facing this generation, a disease with deleterious effects on the health and economic systems worldwide. We hypothesize that DC vaccine therapy may provide a potential treatment strategy to help combat COVID-19. Cancer patients are at the top of the vulnerable population owing to their immune-compromised status. In this review, we discuss DC vaccine therapy in the light of the body's immunity, cancer, and newly emerging infections such as COVID-19 in hopes of better-customized treatment options for patients with multiple comorbidities.