Lidamycin regulates p53 expression by repressing Oct4 transcription

Antibody MYH9 and Antibiotic Lidamycin Inhibit the Growth and Proliferation of Lung Cancer Cells and Induce Their Apoptosis

The aim of this study was to investigate the impact of the antibiotic lidamycin (LDM) and the targeted therapy with the antibody Myosin heavy chain 9 (MYH9) on cancer cells, aiming to provide insights for cancer treatment. In this study, antibiotics and targeted antibodies were used in cancer cells, and then their effects on cell growth, proliferation, apoptosis regulation, and related proteins were measured, and comparative analysis was conducted on the effects of different drug concentrations on the growth of cancer cells. In H460, the apoptotic effect of 2 nM LDM on cells reached 70%. LDM had a downward trend on the levels of B-cell lymphoma-2 (Bcl-2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in cells. The inhibitory effects of LDM at different concentrations on human large cell lung cancer H460 transplanted tumor in nude mice reached 53.20% and 69.80%, and the inhibitory effects on the growth of lung adenocarcinoma transplanted tumor in nude mice reached 40.20% and 58.30%. The expression of MYH9 (myosin, heavy polypeptide 9, non-muscle) in human lung cancer tissues and adjacent tissues reached more than 80%. At the concentration of 300 μM, antibody MYH9 inhibited cell growth by 30%, and the migration rate was also reduced by 25%. The inhibitory effect of siRNA after knocking out the MYH9 gene on cancer cells reached 70%. Antibiotic LDM and targeted antibody MYH9 can inhibit the growth, proliferation, and migration of cancer cells, promote cancer cell apoptosis, and have certain clinical significance for the treatment of cancer patients.

A new TROP2-targeting antibody-drug conjugate shows potent antitumor efficacy in breast and lung cancers

Trophoblast cell surface antigen 2 (Trop2) is considered to be an attractive therapeutic target in cancer treatments. We previously generated a new humanized anti-Trop2 antibody named hIMB1636, and designated it as an ideal targeting carrier for cancer therapy. Lidamycin (LDM) is a new antitumor antibiotic, containing an active enediyne chromophore (AE) and a noncovalently bound apoprotein (LDP). AE and LDP can be separated and reassembled, and the reassembled LDM possesses cytotoxicity similar to that of native LDM; this has made LDM attractive in the preparation of gene-engineering drugs. We herein firstly prepared a new fusion protein hIMB1636-LDP composed of hIMB1636 and LDP by genetic engineering. This construct showed potent binding activities to recombinant antigen with a KD value of 4.57 nM, exhibited binding to Trop2-positive cancer cells and internalization and transport to lysosomes, and demonstrated powerful tumor-targeting ability in vivo. We then obtained the antibody-drug conjugate (ADC) hIMB1636-LDP-AE by molecular reconstitution. In vitro, hIMB1636-LDP-AE inhibited the proliferation, migration, and tumorsphere formation of tumor cells with half-maximal inhibitory concentration (IC50) values at the sub-nanomolar level. Mechanistically, hIMB1636-LDP-AE induced apoptosis and cell-cycle arrest. In vivo, hIMB1636-LDP-AE also inhibited the growth of breast and lung cancers in xenograft models. Moreover, compared to sacituzumab govitecan, hIMB1636-LDP-AE showed more potent antitumor activity and significantly lower myelotoxicity in tumors with moderate Trop2 expression. This study fully revealed the potent antitumor efficacy of hIMB1636-LDP-AE, and also provided a new preparation method for LDM-based ADC, as well as a promising candidate for breast cancer and lung cancer therapeutics.

Cell cycle and pluripotency: Convergence on octamer‑binding transcription factor 4 (Review)

Embryonic stem cells (ESCs) have unlimited expansion potential and the ability to differentiate into all somatic cell types for regenerative medicine and disease model studies. Octamer-binding transcription factor 4 (OCT4), encoded by the POU domain, class 5, transcription factor 1 gene, is a transcription factor vital for maintaining ESC pluripotency and somatic reprogramming. Many studies have established that the cell cycle of ESCs is featured with an abbreviated G1 phase and a prolonged S phase. Changes in cell cycle dynamics are intimately associated with the state of ESC pluripotency, and manipulating cell-cycle regulators could enable a controlled differentiation of ESCs. The present review focused primarily on the emerging roles of OCT4 in coordinating the cell cycle progression, the maintenance of pluripotency and the glycolytic metabolism in ESCs.