SWI/SNF family mutations in advanced NSCLC: genetic characteristics and immune checkpoint inhibitors' therapeutic implication.

BACKGROUND: SWItch/Sucrose NonFermentable (SWI/SNF) mutations have garnered increasing attention because of their association with unfavorable prognosis. However, the genetic landscape of SWI/SNF family mutations in Chinese non-small-cell lung cancer (NSCLC) is poorly understood. In addition, the optimal treatment strategy has not yet been determined. PATIENTS AND METHODS: We collected sequencing data on 2027 lung tumor samples from multiple centers in China to comprehensively analyze the genomic characteristics of the SWI/SNF family within the Chinese NSCLC population. Meanwhile, 519 patients with NSCLC from Sun Yat-sen University Cancer Center were enrolled to investigate the potential implications of immunotherapy on patients with SWI/SNF mutations and to identify beneficial subpopulations. We also validated our findings in multiple publicly available cohorts. RESULTS: Approximately 15% of Chinese patients with lung cancer harbored mutations in the SWI/SNF chromatin remodeling complex, which were mutually exclusive to the EGFR mutations. Patients with SWI/SNFmut NSCLC who received first-line chemoimmunotherapy had better survival outcomes than those who received chemotherapy alone (median progression-free survival: 8.70 versus 6.93 months; P = 0.028). This finding was also confirmed by external validation using the POPLAR/OAK cohort. SWI/SNFmut NSCLC is frequently characterized by high tumor mutational burden and concurrent TP53 or STK11/KEAP mutations. Further analysis indicated that TP53 and STK11/KEAP1 mutations could be stratifying factors in facilitating personalized immunotherapy and guiding patient selection. CONCLUSIONS: This study provides a step forward in understanding the genetic and immunological characterization of SWI/SNF genetic alterations. Moreover, our study reveals substantial benefits of immunotherapy over chemotherapy for SWI/SNF-mutant patients, especially the SWI/SNFmut and TP53mut subgroups.

Immunoregulatory effect of neuronal-like cells in inducting differentiation of bone marrow mesenchymal stem cells.

OBJECTIVE: To evaluate the immune activity of bone marrow mesenchymal stem cells (BMSCs), and explore the biological characteristics and capabilities of BMSCs and the potential to be differentiated into neuronal cells in vitro. MATERIALS AND METHODS: The BMSCs were isolated and proliferated in vitro to generate the xenogeneic mixed lymphocyte reaction. Moreover, peripheral BMSCs (pBMSCs) were added according to different ratios, which methods were stated as follows: 1: Dulbecco's Modified Eagle Medium (DMEM) + 10% Fetal Bovine Serum (FBS) + 1 µmol/L all-trans-retinoic acid (ATRA) + 20 µg/L basic fibroblast growth factor (bFGF) + 20 µg/L epidermal growth factor (EGF); 2: DMEM + 2% dimethyl sulfoxide (DMSO) + 100 µmol/L butylated hydroxyanisole (BHA). The immunofluorescence and immunohistochemical staining were finally used to evaluate the differentiation capabilities of human BMSCs (hBMSCs) induced in neuronal cells. RESULTS: hBMSCs inhibited the lymphocyte proliferation in the mixed lymphocyte reaction (MLR) system at a proportional inhibition rate with additional numbers of stem cells. At hour 2 after culture with method 1, the plasma of hBMSCs shrank to nuclei and perinuclear bodies and was visualized under the light microscope. At hours 3-5, most of the hBMSCs formed neuron-like cells with total cell number unchanged. Afterward, the hBMSCs turned into bipolar or multipolar shaped cells and interconnected into a large network at Day 3. With immunofluorescence and immunohistochemical staining, 60-70% of the hBMSCs showed neurospecific enolase (NSE) positive and 45-50% glial fibrillary acidic protein (GFAP) positive while the Nestin-positive cells decreased to 3.4%. However, when cultured 2 hours with method 2, the most of the hBMSCs formed bipolar or multipolar shaped cells, then died after 48 hours. 40-50% NSE and 35-40% GFAP were positively expressed. Significantly, the rate of Nestin-positive cells decreased from 63% to 1.6% from hour 2 after culture to hour 48. CONCLUSIONS: hBMSCs may be effective for cell therapy and tissue engineering for the capability of differentiating into neuronal-like cells, as well as the capability of inhibiting lymphocyte proliferation in MLR system.

Long-term follow-up of a phase III study comparing radiotherapy with or without weekly oxaliplatin for locoregionally advanced nasopharyngeal carcinoma.

BACKGROUND: Previous results from our trial showed that adding oxaliplatin to radiotherapy (RT) increased survival in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) at 2 years. Here, we present the data of long-term efficacy and late toxic effects. PATIENTS AND METHODS: Between January 2001 and January 2003, 115 Patients with nonkeratinizing/undifferentiated locoregionally advanced NPC were randomly to receive either RT alone (n = 56) or plus concurrent oxaliplatin 70 mg/m(2) weekly for six cycles (n = 59). RESULTS: After a median follow-up of 114 months (range 18-139 months), the 5-year overall survival (OS) and metastasis-free survival (MFS) rates in the concurrent chemoradiotherapy (CCRT) group were significantly higher than those observed in the RT-alone group (OS, 73.2% versus 60.2%, P = 0.028; MFS, 74.7% versus 63.0%, P = 0.027). However, CCRT did not improve locoregional failure-free survival significantly. Subgroup analyses showed that the superiorities of CCRT mainly existed in the T3-4N0-1 stage subgroup (OS: HR = 0.394, P = 0.034). The grade 3/4 late toxic effects were similar in the two groups. CONCLUSION(S): The long-term follow-up data confirms the role of CCRT as a treatment of locoregionally advanced NPC. Oxaliplatin can be considered as an alternative optional therapeutic regimen for these patients due to its high efficiency and low toxic effect.

Carcinogenicity of catechol estrogens in Syrian hamsters.

Estradiol and other estrogens induce renal carcinoma in male Syrian hamsters. The mechanism of carcinogenesis still remains unclear. Activation of estrogens to catechol metabolites has in the past been postulated to play a role in estrogen-induced carcinogenesis. Therefore, the carcinogenic activity of catechol estrogens was investigated. After 175 days of treatment, 4-hydroxyestradiol was found to be as carcinogenic as estradiol in male Syrian hamsters (4/5 and 4/5 animals with kidney tumors, respectively). Animals treated with 2-hydroxyestradiol (0/5) or 2-methoxyestradiol (0/6) did not develop renal carcinoma. The catechol estrogens failed to be mutagenic in the Ames test (reversions of his- S. typhimurium to histidine prototrophy in the TA 100 strain). The lack of carcinogenic activity of 2-hydroxyestradiol was not due to a failure to stimulate estrogen-dependent tumor growth. Growth of H-301 cells, an estrogen-dependent hamster kidney tumor cell line, was supported in vivo by estrogens in the following order: estradiol greater than 4-hydroxyestradiol greater than 2-hydroxyestradiol. Stimulation of tumor growth by 2-methoxyestradiol was not detected. It was concluded that the carcinogenic activity of 4-hydroxyestradiol was consistent with a role of catechol metabolites in estrogen-induced carcinogenesis. However, the intrinsic carcinogenic or hormonal activity of 2-hydroxyestradiol probably can not be assessed accurately in vivo because of its rapid methylation and metabolic clearance.

Metabolism of the carcinogen 1,2-dimethylhydrazine by isolated human colon microsomes and human colon tumor cells in culture.

Human colon microsomes catalyze the metabolism of the model colon carcinogen 1,2-dimethylhydrazine. Activity appears to be distributed in a gradient towards the lower end of the colon. Highest activities were observed for microsomes prepared from the descending segment of the colon with the transverse segment exhibiting lower activities, while the ascending segment showed the lowest rate of metabolism. Dimethylhydrazine metabolism in each segment is inhibited significantly by inhibitors of the cytochrome P-450-dependent mixed function oxidase system. Microsomes prepared from a human colon tumor cell also catalyze the metabolism of 1,2-dimethylhydrazine. Metabolic activity in the cell line can be induced two-fold by treatment of cells with phenobarbital and three-fold by treatment of the cells with phenobarbital plus hydrocortisone. These results show that human colon activates 1,2-dimethylhydrazine and suggest that the human colon may be capable of activating other carcinogens in situ.

Effects of cyclophosphamide and polycyclic aromatic hydrocarbons on cell growth and mixed-function oxidase activity in a human colon tumor cell line.

Human colon tumor cells (cell line LS174T) retain a cytochrome P-450-containing drug metabolism system capable of hydroxylating polycyclic hydrocarbons and the anticancer drug cyclophosphamide. The hydroxylation of benzo(a)pyrene by human colon tumor cells is highly inducible. Phenobarbital plus hydrocortisone induce benzo(a)pyrene hydroxylation activities 10-fold, while benz(a)anthracene induces the rate of hydroxylation 30-fold. Cytochrome P-450 specific content is increased 2- to 3-fold by treatment with phenobarbital plus hydrocortisone and benz(a)anthracene, respectively. Addition of cyclophosphamide alone results in no increase in hydroxylation activities but causes a decrease in cell growth rate. The combination of cyclophosphamide with either of the inducers phenobarbital plus hydrocortisone or benz(a)anthracene results in markedly enhanced inhibition of cell growth as judged both by a decrease in the number of cells per plate and in the incorporation of [3H]thymidine into DNA. Thus, these data show that cyclophosphamide is cytotoxic to human colon tumor cells and that the cytotoxicity is enhanced by simultaneous administration of benz(a)anthracene or phenobarbital plus hydrocortisone to the tissue cultures.

Role of colonic cytochrome P-450 in large bowel carcinogenesis.

Rat colon mucosa microsomes contain a competent mixed function oxidase system that hydroxylates the N-methyl drugs benzphetamine and ethylmorphine, the O-alkyl drugs p-nitroanisole and p-nitrophenetole and the polycyclic carcinogen benzo[alpha]pyrene. The colon system's hydroxylation activities can be selectively induced by pretreatment with phenobarbital or beta-naphthoflavone and can be selectively inhibited by SKF-525A or 7,8-benzoflavone. The colon microsomal system has been solubilized with the non-ionic detergent Renex 690 and resolved by column chromatography into its components cytochrome P-450 and cytochrome P-450 reductase. Colon cytochrome P-450 and cytochrome P-450 reductase can be recombined to reconstitute hydroxylation activity. The colon system is also able to activate carcinogens to mutagenic metabolites as demonstrated in the Ames test system. In addition, the activity of the colon system is markedly increased by pretreatment with gastrointestinal hormones.

The drug metabolism systems of liver and liver tumors: a comparison of activities and characteristics.

Transplantable rat liver tumors 5123 t.c., 7288 ct.c., 5123 t.c.(H) and the Novikoff hepatoma have active mixed function oxidase systems capable of metabolizing a variety of drug and polycyclic hydrocarbon substrates. The tumor drug metabolism systems are at best 20% as active as rat liver. The tumor drug metabolism activities are induced by pretreatment with phenobarbital or beta-naphthoflavone and can be inhibited with specific inhibitors such as carbon monoxide or 7,8-benzoflavone. Tumor drug metabolism systems appear to consist of cytochrome P-450 and cytochrome P-450 reductase. The properties of the two protein components from tumors are highly similar to the corresponding components of the liver drug metabolism system. Cytochrome P-450 reductase has been at least partially purified from the Novikoff hepatoma and hepatoma 5123 t.c.(H). The kinetic and physical properties of the tumor reductases are similar to those of the liver reductase except that the Km of hepatoma 5123 t.c.(H) reductase, but not of the Novikoff hepatoma reductase for NADPH, is elevated an order of magnitude over the Km of the liver reductase. The mechanism for the interaction of electron donor and electron acceptor with liver or tumor reductases seems to be a sequential reaction mechanism. Experiments on the NADP-inhibition of the interaction of NADPH and cytochrome c with liver reductase indicate that NADP is competitive with NADPH and noncompetitive with cytochrome c. This result is consistent with the postulate of a sequential reaction for NADPH-cytochrome P-450 reductases of liver and tumors. These data support the conclusions that an active drug metabolism system is present in liver tumors and that the tumor systems are constituted like the liver system.

Drug metabolism in the Novikoff hepatoma: evidence for a mixed function oxidase system and partial purification of cytochrome P-450 reductase.

Novikoff kepatoma microsomes catalyze the hydroxylation of benzphetamine and ethylmorphine at rates less than 1% of those of liver microsomes but catalyze the hydroxylation of p-nitroanisole and p-nitrophenetole at rates about 40% of those of liver microsomes. Benzo[a]pyrene hydroxylation is also catalyzed by Novikoff hepatoma microsomes at about 2% of the rate of liver microsomes. Like the hepatic microsomal system the rates of substrate hydroxylation by Novikoff hepatoma microsomes can be increased by pretreatment with phenobarbital/hydrocortisone or beta-naphthoflavone and inhibited by carbon monoxide, SKF-525A, and 7,8-benzoflavone. In addition, NADPH-cytochrome P-450 reductase (NADPH:ferricytochrome oxidoreductase, EC 1.6.2.4) has been partially purified from Novikoff hepatoma ascites cells and some properties are described. The induction and inhibition characteristics of the Novikoff hepatoma microsomal hydroxylation activities and the isolation of a cytochrome P-450 reductase from the hepatoma are consistent with the presence of a functional mixed function oxidase system in the Novikoff hepatoma, analogous to that present in liver endoplasmic reticulum.

Activation of carcinogens and mutagens by rat colon mucosa.

Colon mucosal cells can catalyze the activation of precarcinogens to mutagenic metabolites without the intermediacy of intestinal bacteria as shown in a mutagenesis assay system composed of Salmonella typhimurium strain TA100 and the 9000 X g supernatant fraction of rat colon mucosal cells. Pretreatment of rats with beta-naphtoflavone increased the activation of 2-aminoanthracene 10- to 20-fold and the activation of benzo(a)pyrene 4-fold. Pretreatment of rats with Aroclor 1254 doubled the activation of 2-aminoanthracene over control but had no effect on the activation of benzo(a)pyrene. The activation of 2-aminoanthracene and benzo(a)pyrene by liver was induced significantly by pretreatment with beta-naphthoflavone and Aroclor 1254. Phenobarbital/hydrocortisone pretreatment did not increase the activation by the colon system of any precarcinogen tested but did increase the activation of 2-aminoanthracene, cyclophosphamide, and isophosphamide by the liver system. The activation of precarcinogens in the bacterial test system is directly correlated with the activities of the pretreated colon and liver preparations toward several drug and polycyclic hydrocarbon substrates assayed in vitro.

Pharmacologic effects of gastrointestinal hormones on intestinal oxygen consumption and blood flow.

The vasoactive effects of cholecystokinin-octapeptide (CCK-OP), pentagastrin, synthetic secretin, glucagon, and acetylcholine were assessed in the intestinal circulation of the dog. In pharmacologic doses of glucagon, CCK-OP, and, to a lesser degree, pentagastrin significantly increased blood flow and oxygen consumption. Atropine blocked the vasodilator effects of CCK-OP, pentagastrin, and acetylcholine but did not block those of glucagon. Neither the alpha-adrenergic blocker, phenoxybenzamine, nor the beta-adrenergic blocker, propranolol, blocked the vasodilator response to pentagastrin. Synthetic secretin had no significant effect on either blood flow or oxygen consumption in the intestinal segment. The vasodilator response to CCK-OP and pentagastrin appears to be mediated specifically through cholinergic receptors.