New insights into the important roles of phase seperation in the targeted therapy of lung cancer

Abstract Lung cancer is a complex and heterogeneous disease characterized by abnormal growth and proliferation of lung cells. It is the leading cause of cancer-related deaths worldwide, accounting for approximately 18% of all cancer deaths. In recent years, targeted therapy has emerged as a promising approach to treat lung cancer, which involves the use of drugs that selectively target specific molecules or signaling pathways that are critical for the growth and survival of cancer cells. Liquid–liquid phase separation (LLPS) is a fundamental biological process that occurs when proteins and other biomolecules separate into distinct liquid phases in cells. LLPS is essential for various cellular functions, including the formation of membraneless organelles, the regulation of gene expression, and the response to stress and other stimuli. Recent studies have shown that LLPS plays a crucial role in targeted therapy of lung cancer, including the sequestration of oncogenic proteins and the development of LLPS-based drug delivery systems. Understanding the mechanisms of LLPS in these processes could provide insights into new therapeutic strategies to overcome drug resistance in lung cancer cells

Increased expression of FAT4 suppress metastasis of lung adenocarcinoma through regulating MAPK pathway and associated with immune cells infiltration

Abstract FAT4 is an extremely large atypical cadherin with crucial roles in the control of planar cell polarity (PCP) and regulation of the Hippo signaling pathway. Our study aims to clarify the FAT4 expression patterns, as well as the significance of FAT4 in predicting the prognosis and cancer immunity to non‐small cell lung cancer (NSCLC). FAT4 mRNA and protein expressions were both underregulated in NSCLC and associated with poor prognosis in both lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). In addition, overexpress FAT4 with jujuboside A (JUA) or knockdown FAT4 with siRNA regulated the metastasis of LUAD through MAPK pathways. Moreover, the FAT4 expression included multiple immunological components to promote an immunosuppressive tumor microenvironment (TME). Furthermore, a study of the TCGA‐LUAD cohort's DNA methylation results showed that most FAT4 DNA CpG sites were typically hypermethylated in NSCLC relative to the normal lung tissue. The DNA CpG sites cg25879360 and cg26389756 of FAT4 were found to be strongly associated with FAT4 expression in LUAD through the correlation study. In conclusion, this is the first to report the potential function of FAT4 in NSCLC. Hence, FAT4 could be used as a promising prognostic and immunological biomarker for NSCLC

The 3/4- and 3/6-Subfamily Variants of α-Conotoxins GI and MI Exhibit Potent Inhibitory Activity against Muscular Nicotinic Acetylcholine Receptors

α-Conotoxins GI and MI belong to the 3/5 subfamily of α-conotoxins and potently inhibit muscular nicotinic acetylcholine receptors (nAChRs). To date, no 3/4- or 3/6-subfamily α-conotoxins have been reported to inhibit muscular nAChRs. In the present study, a series of new 3/4-, 3/6-, and 3/7-subfamily GI and MI variants were synthesized and functionally characterized by modifications of loop2. The results show that the 3/4-subfamily GI variant GI[∆8G]-II and the 3/6-subfamily variants GI[+13A], GI[+13R], and GI[+13K] displayed potent inhibition of muscular nAChRs expressed in Xenopus oocytes, with an IC50 of 45.4–73.4 nM, similar to or slightly lower than that of wild-type GI (42.0 nM). The toxicity of these GI variants in mice appeared to be about a half to a quarter of that of wild-type GI. At the same time, the 3/7-subfamily GI variants showed significantly lower in vitro potency and toxicity. On the other hand, similar to the 3/6-subfamily GI variants, the 3/6-subfamily MI variants MI[+14R] and MI[+14K] were also active after the addition of a basic amino acid, Arg or Lys, in loop2, but the activity was not maintained for the 3/4-subfamily MI variant MI[∆9G]. Interestingly, the disulfide bond connectivity “C1–C4, C2–C3” in the 3/4-subfamily variant GI[∆8G]-II was significantly more potent than the “C1–C3, C2–C4” connectivity found in wild-type GI and MI, suggesting that disulfide bond connectivity is easily affected in the rigid 3/4-subfamily α-conotoxins and that the disulfide bonds significantly impact the variants’ function. This work is the first to demonstrate that 3/4- and 3/6-subfamily α-conotoxins potently inhibit muscular nAChRs, expanding our knowledge of α-conotoxins and providing new motifs for their further modifications

A Single Amino Acid Replacement Boosts the Analgesic Activity of α-Conotoxin AuIB through the Inhibition of the GABABR-Coupled N-Type Calcium Channel

α-conotoxin AuIB is the only one of the 4/6 type α-conotoxins (α-CTxs) that inhibits the γ-aminobutyric acid receptor B (GABABR)-coupled N-type calcium channel (CaV2.2). To improve its inhibitory activity, a series of variants were synthesized and evaluated according to the structure–activity relationships of 4/7 type α-CTxs targeting GABABR-coupled CaV2.2. Surprisingly, only the substitution of Pro7 with Arg results in a 2–3-fold increase in the inhibition of GABABR-coupled CaV2.2 (IC50 is 0.74 nM); substitutions of position 9–12 with basic or hydrophobic amino acid and the addition of hydrophobic amino acid Leu or Ile at the second loop to mimic 4/7 type α-CTxs all failed to improve the inhibitory activity of AuIB against GABABR-coupled CaV2.2. Interestingly, the most potent form of AuIB[P7R] has disulfide bridges of “1–4, 2–3” (ribbon), which differs from the “1–3, 2–4” (globular) in the isoforms of wildtype AuIB. In addition, AuIB[P7R](globular) displays potent analgesic activity in the acetic acid writhing model and the partial sciatic nerve injury (PNL) model. Our study demonstrated that 4/6 type α-CTxs, with the disulfide bridge connectivity “1–4, 2–3,” are also potent inhibitors for GABABR-coupled CaV2.2, exhibiting potent analgesic activity