Crenolanib Regulates ERK and AKT/mTOR Signaling Pathways in RAS/BRAF-Mutated Colorectal Cancer Cells and Organoids

Pterostilbene and 6-shogaol exhibit inhibitory effects on sunitinib resistance and motility by suppressing the RLIP76-initiated Ras/ERK and Akt/mTOR pathways in renal cancer cells

Sunitinib (SUN) is the first-line targeted therapeutic drug for advanced renal cell carcinoma (RCC). However, SUN resistance is frequently observed to result in tumor metastasis, with a poor survival rate. Therefore, finding an effective and safe adjuvant to reduce drug resistance is important for RCC treatment. Pterostilbene (PTE) and 6-shogaol (6-S) are natural phytochemicals found in edible sources and have potential applications against various cancers. However, the biological mechanisms of PTE and 6-S in SUN-resistant RCC are still unclear. Accordingly, this study investigated the regulatory effects of PTE and 6-S on cell survival, drug resistance, and cell invasion in 786-O and SUN-resistant 786-O (786-O SUNR) cells, respectively. The results demonstrated that PTE and 6-S induced apoptosis in both cell lines by upregulating the Bax/Bcl-2 ratio. Additionally, PTE and 6-S increased SUN sensitivity by inhibiting the expression of the RLIP76 transport protein, reduced cell invasion and downregulated MMP expression in both 786-O and 786-O SUNR cells. Mechanistically, PTE, and 6-S significantly and dose-dependently suppressed the RLIP76-initiated Ras/ERK and Akt/mTOR pathways. In summary, PTE and 6-S induce apoptosis, enhance SUN sensitivity, and inhibit migration in both 786-O and 786-O SUNR cells. These novel findings demonstrate the potential of PTE and 6-S as target therapeutic adjuvants for RCC treatment.

Analysis of CD74 Occurrence in Oncogenic Fusion Proteins

CD74 is a type II cell surface receptor found to be highly expressed in several hematological and solid cancers, due to its ability to activate pathways associated with tumor cell survival and proliferation. Over the past 16 years, CD74 has emerged as a commonly detected fusion partner in multiple oncogenic fusion proteins. Studies have found CD74 fusion proteins in a range of cancers, including lung adenocarcinoma, inflammatory breast cancer, and pediatric acute lymphoblastic leukemia. To date, there are five known CD74 fusion proteins, CD74-ROS1, CD74-NTRK1, CD74-NRG1, CD74-NRG2α, and CD74-PDGFRB, with a total of 16 different variants, each with unique genetic signatures. Importantly, the occurrence of CD74 in the formation of fusion proteins has not been well explored despite the fact that ROS1 and NRG1 families utilize CD74 as the primary partner for the formation of oncogenic fusions. Fusion proteins known to be oncogenic drivers, including those of CD74, are typically detected and targeted after standard chemotherapeutic plans fail and the disease relapses. The analysis reported herein provides insights into the early intervention of CD74 fusions and highlights the need for improved routine assessment methods so that targeted therapies can be applied while they are most effective.

Cancer Stem Cells Persist Despite Cellular Damage, Emergence of the Refractory Cell Population

PURPOSE

Cancer stem cells (CSCs) are responsible for chemotherapy resistance and have unique properties that protect them from chemotherapy. Investigating CSCs may help to identify the population that is more resistant to treatments, leading to recurrence. We evaluated persisting CSCs, emerging after chemotherapy that cause tumor recurrence.

METHODS

Using human colorectal cancer organoids prepared from surgical specimens, we looked at changes in CSCs, the emergence and changes in the original population, which single-cell analysis identified.

RESULTS

With regards to changes in cancer stem cell markers, CD44 showed low levels after 5-fluorouracil administration. Once the CD44-ve population was sorted and cultured, the CD44+ve population gradually emerged, and the CD44-ve population decreased. Compared with the CD44-ve population of an organoid parent, the CD44-ve population proliferated after chemotherapeutic agent stimulation. The CD44-ve population was derived from the CD44+ve population before chemotherapeutic agents. In addition, when the CD44 variants were evaluated, the CD44v9 population remained. In single-cell analysis, we found that POU5F1 was highly expressed in the CD44low population. Velocity analysis showed that the CD44-ve population was induced after chemotherapy and expressed POU5F1. POU5F1-EGFP-Casp9 transfected organoids resulted in the appearance of a CD44-ve population after administration of a chemotherapeutic reagent. Both in vivo and in vitro, the dimerizer administration inhibited tumor growth significantly.

CONCLUSIONS

POU5F1 is involved in chemotherapy resistance in relation to stemness. For the treatment against refractory tumors, such as the recurrence after chemotherapy, the treatment should target the emerging specific population such as CD44 (or CD44v9) and proliferative cancer cells.

KRAS Mutations in Solid Tumors: Characteristics, Current Therapeutic Strategy, and Potential Treatment Exploration

Kristen rat sarcoma (KRAS) gene is one of the most common mutated oncogenes in solid tumors. Yet, KRAS inhibitors did not follow suit with the development of targeted therapy, for the structure of KRAS has been considered as being implausible to target for decades. Chemotherapy was the initial recommended therapy for KRAS-mutant cancer patients, which was then replaced by or combined with immunotherapy. KRAS G12C inhibitors became the most recent breakthrough in targeted therapy, with Sotorasib being approved by the Food and Drug Administration (FDA) based on its significant efficacy in multiple clinical studies. However, the subtypes of the KRAS mutations are complex, and the development of inhibitors targeting non-G12C subtypes is still at a relatively early stage. In addition, the monotherapy of KRAS inhibitors has accumulated possible resistance, acquiring the exploration of combination therapies or next-generation KRAS inhibitors. Thus, other non-target, conventional therapies have also been considered as being promising. Here in this review, we went through the characteristics of KRAS mutations in cancer patients, and the prognostic effect that it poses on different therapies and advanced therapeutic strategy, as well as cutting-edge research on the mechanisms of drug resistance, tumor development, and the immune microenvironment.

The pivotal application of patient-derived organoid biobanks for personalized treatment of gastrointestinal cancers

Gastrointestinal cancers (GICs) occupy more than 30% of the cancer-related incidence and mortality around the world. Despite advances in the treatment strategies, the long-term overall survival has not been improved for patients with GICs. Recently, the novel patient-derived organoid (PDO) culture technology has become a powerful tool for GICs in a manner that recapitulates the morphology, pathology, genetic, phenotypic, and behavior traits of the original tumors. Excitingly, a number of evidences suggest that the versatile technology has great potential for personalized treatment, suppling the clinical application of molecularly guided personalized treatment. In the paper, we summarize the literature on the topics of establishing organoid biobanks of PDOs, and their application in the personalized treatment allowing for radiotherapy, chemotherapy, targeted therapy, and immunotherapy selection for GICs. Despite the limitations of current organoid models, high-throughput drug screening of GIC PDO combined with next-generation sequencing technology represents a novel and pivotal preclinical model for precision medicine of tumors and has a great value in promoting the transformation from basic cancer research to clinical application.

Targeting the PDGF/PDGFR signaling pathway for cancer therapy: A review

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are expressed in a variety of tumors. Activation of the PDGF/PDGFR signaling pathway is associated with cancer proliferation, metastasis, invasion, and angiogenesis through modulating multiple downstream pathways, including phosphatidylinositol 3 kinase/protein kinase B pathway and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Therefore, targeting PDGF/PDGFR signaling pathway has been demonstrated to be an effective strategy for cancer therapy, and accordingly, some great progress has been made in this field in the past few decades. This review will focus on the PDGF isoforms and their binding with the related PDGFRs, the PDGF/PDGFR signaling and regulation, and especially present strategies and inhibitors developed for cancer therapy, and the related clinical benefits and side effects.