Dibenzo[def,p]chrysene (DBP), a representative example of the class of polycyclic aromatic hydrocarbon (PAH), is known to induce tumors in multiple organ sites including the ovary, lung, mammary glands, and oral cavity in rodents. The goal of this study was to test the hypothesis that the levels of DBP and its metabolites that reach and retain the levels for an extended time in the target organs as well as the capacity of these organs to metabolize this carcinogen to active metabolites that can damage DNA may account for its tissue selective tumorigenicity. Therefore, we used the radiolabeled [³H] DBP to accurately assess the tissue distribution, excretion, and pharmacokinetics of this carcinogen. We also compared the levels of DBPDE-DNA adducts in a select target organ (ovary) and nontarget organs (kidney and liver) in mice treated orally with DBP. Our results showed that after 1 week, 91.40 ± 7.23% of the radioactivity was recovered in the feces; the corresponding value excreted in the urine was less than 2% after 1 week. After 24 h, the stomach had the highest radioactivity followed by the intestine and the liver; however, after 1 week, levels of the radioactivity in these organs were the lowest among tissues examined including the ovary and liver; the pharmacokinetic analysis of DBP was conducted using a one compartment open model. The level of (−)-anti-trans-DBPDE-dA in the ovaries (8.91 ± 0.08 adducts/10⁷ dA) was significantly higher (p < 0.01) than the levels of adducts in kidneys (0.69 ± 0.09 adducts/10⁷ dA) and livers (0.63 ± 0.11 adducts/10⁷ dA). Collectively, the results of the tissue distribution and pharmacokinetic analysis may not fully support our hypothesis, but the capacity of the target organs vs nontarget organs to metabolize DBP to active intermediates that can damage DNA may account for its tissue selective tumorigenicity.

Protein Kinase CK2 (Casein Kinase 2 or CK2) is a constitutively active serine-threonine kinase overactive in human malignancies. Increased expression and activity of CK2 in Acute Myeloid Leukemia (AML) is associated with a poor outcome. CK2 promotes AML cell survival by impinging on multiple oncogenic signaling pathways. The selective small-molecule CK2 inhibitor CX-4945 has shown in vitro cytotoxicity in AML. Here, we report that CX-4945 has a strong in vivo therapeutic effect in preclinical models of AML. The analysis of genome-wide DNA-binding and gene expression in CX-4945 treated AML cells shows that one mechanism, by which CK2 inhibition exerts a therapeutic effect in AML, involves the revival of IKAROS tumor suppressor function. CK2 phosphorylates IKAROS and disrupts IKAROS’ transcriptional activity by impairing DNA-binding and association with chromatin modifiers. Here, we demonstrate that CK2 inhibition decreases IKAROS phosphorylation and restores IKAROS binding to DNA. Further functional experiments show that IKAROS negatively regulates the transcription of anti-apoptotic genes, including BCL-XL (B cell Lymphoma like–2 like 1, BCL2L1). CX-4945 restitutes the IKAROS-mediated repression of BCL-XL in vivo and sensitizes AML cells to apoptosis. Using CX-4945, alongside the cytotoxic chemotherapeutic drug daunorubicin, augments BCL-XL suppression and AML cell apoptosis. Overall, these results establish the in vivo therapeutic efficacy of CX-4945 in AML preclinical models and determine the role of CK2 and IKAROS in regulating apoptosis in AML. Furthermore, our study provides functional and mechanistic bases for the addition of CK2 inhibitors to AML therapy.

Immunotherapy targeting program cell death protein 1 (PD-1) in addition to chemotherapy has improved the survival of triple-negative breast cancer (TNBC) patients. However, the development of resistance and toxicity remain significant problems. Using the translationally relevant 4T1 mouse model of TNBC, we report here that dietary administration of the phytochemical quercetin enhanced the antitumor action of Cyclophosphamide, a cytotoxic drug with significant immunogenic effects that is part of the combination chemotherapy used in TNBC. We observed that quercetin favorably modified the host fecal microbiome by enriching species such as Akkermansia muciniphilia, which has been shown to improve response to anti-PD-1 therapy. We also show that quercetin and, to a greater extent, Cyclophosphamide increased the systemic frequency of T cells and NK cells. In addition, Cyclophosphamide alone and in combination with quercetin reduced the frequency of Treg, which is consistent with an antitumor immune response. On the other hand, Cyclophosphamide did not significantly alter the host microbiome, suggesting complementarity between microbiome- and immune-mediated mechanisms in potentiating the antitumor action of Cyclophosphamide by quercetin. Overall, these results support the potential for microbiota-centered dietary intervention to overcome resistance to chemoimmunotherapy in TNBC.

The introduction of selenium (Se) into organic scaffolds has been demonstrated to be a promising framework in the field of medicinal chemistry. A novel design of nonsteroidal anti-inflammatory drug (NSAID) derivatives based on a bioisosteric replacement via the incorporation of Se as diacyl diselenide is reported. The antioxidant activity was assessed using the DPPH radical scavenging assay. The new Se-NSAID derivatives bearing this unique combination showed antioxidant activity in a time- and dose-dependent manner, and also displayed different antiproliferative profiles in a panel of eight cancer cell lines as determined by the MTT assay. Ibuprofen derivative 5 was not only the most antioxidant agent, but also selectively induced toxicity in all the cancer cell lines tested (IC₅₀ < 10 µM) while sparing nonmalignant cells, and induced apoptosis partially without enhancing the caspase 3/7 activity. Furthermore, NSAID derivative 5 significantly suppressed tumor growth in a subcutaneous colon cancer xenograft mouse model (10 mg/kg, TGI = 72%, and T/C = 38%) without exhibiting any apparent toxicity. To our knowledge, this work constitutes the first report on in vitro and in vivo anticancer activity of an unprecedented Se-NSAID hybrid derivative and its rational use for developing precursors for bioisosteric selenocompounds with appealing therapeutic applications.

Approximately 70% of oropharyngeal squamous carcinomas (OPSCC) are associated with human papillomavirus (HPV). Although patients with HPV-positive (HPV+) tumors generally have better outcomes than those with HPV-negative tumors, a subset of HPV+ positive patients do have poor outcomes. Our previous work suggested that tumors with integrated virus exhibit significantly greater genome-wide genomic instability than those with only episomal viral genomes, and patients with HPV+ OPSCC with episomal viral genomes had better outcomes. To explore the causal relation between viral integration and genomic instability, we have examined the time course of viral integration and genetic instability in tonsillar keratinocytes transformed with HPV16. HPV-infected human tonsil keratinocyte cell lines were continuously passaged, and every fifth passage, some cells were retained for genomic analysis. Whole-genome sequencing and optical genomic mapping confirmed that virus integrated in five of six cell lines while remaining episomal in the sixth. In all lines, genome instability occurred during early passages but essentially ceased following viral integration; however, it continued to occur in later passages in the episomal line. To test tumorigenicity of the cell lines, cells were injected subcutaneously into the flanks of nude mice. A cell line with the integrated virus induced tumors following injection in the nude mouse whereas that with the episomal virus did not. Implications: Genomic instability in HPV OPSCC tumors is not the result of viral integration but likely promotes integration. Moreover, transformants with episomal virus seem to be less tumorigenic than those with integrated virus.

While tobacco smoking is a risk factor in the development of oral squamous cell carcinoma (OSCC), only a fraction of smokers develop the disease. Compelling evidence shows that microbial community composition is associated with carcinogenesis, suggesting that the microbiome may play a role in cancer development of smokers. We previously showed that black raspberry (BRB) protects against OSCC induced by the tobacco constituent dibenzo[def,p]chrysene (DBP) via alteration of genetic and epigenetic markers in a manner consistent with its cancer preventive activity. In the present study, we conducted a mouse experiment to investigate the effects of BRB and DBP individually and in combination on the oral and gut microbiota. DBP-induced DNA damage in the mouse oral cavity is an essential step for the development of OSCC in mice. 16S rRNA gene sequencing revealed that BRB significantly increased microbial diversity and shifted microbiome composition in the gut and oral cavity, whereas DBP had no significant effect. In both gut and oral microbiota, Akkermansia muciniphila was significantly reduced after BRB treatment; however, this was not consistent with pure culture in vitro assays suggesting that the impact of BRB on A. muciniphila may be mediated through indirect mechanisms including the host or other microbes. Indeed BRB, but not DBP, was found to modulate the growth kinetics of human gut microbes in vitro including lactic acid bacteria and Bacteroides spp. The results of the current study further emphasize the interplay of microbiome and environmental factors in the development and prevention of OSCC. Prevention Relevance: Our work clearly demonstrates the modulatory impact of BRB on both gut and oral microbiomes within a DBP-induced OSCC mouse model and paves the way for future research examining a causal role of BRB–microbiota interactions at different stages of disease progression.