Microbes and Cancer.

Commensal microorganisms (the microbiota) live on all the surface barriers of our body and are particularly abundant and diverse in the distal gut. The microbiota and its larger host represent a metaorganism in which the cross talk between microbes and host cells is necessary for health, survival, and regulation of physiological functions locally, at the barrier level, and systemically. The ancestral molecular and cellular mechanisms stemming from the earliest interactions between prokaryotes and eukaryotes have evolved to mediate microbe-dependent host physiology and tissue homeostasis, including innate and adaptive resistance to infections and tissue repair. Mostly because of its effects on metabolism, cellular proliferation, inflammation, and immunity, the microbiota regulates cancer at the level of predisposing conditions, initiation, genetic instability, susceptibility to host immune response, progression, comorbidity, and response to therapy. Here, we review the mechanisms underlying the interaction of the microbiota with cancer and the evidence suggesting that the microbiota could be targeted to improve therapy while attenuating adverse reactions.

A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2.

Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.

Neutrophils Driving Unconventional T Cells Mediate Resistance against Murine Sarcomas and Selected Human Tumors.

Neutrophils are a component of the tumor microenvironment and have been predominantly associated with cancer progression. Using a genetic approach complemented by adoptive transfer, we found that neutrophils are essential for resistance against primary 3-methylcholantrene-induced carcinogenesis. Neutrophils were essential for the activation of an interferon-γ-dependent pathway of immune resistance, associated with polarization of a subset of CD4- CD8- unconventional αß T cells (UTCαß). Bulk and single-cell RNA sequencing (scRNA-seq) analyses unveiled the innate-like features and diversity of UTCαß associated with neutrophil-dependent anti-sarcoma immunity. In selected human tumors, including undifferentiated pleomorphic sarcoma, CSF3R expression, a neutrophil signature and neutrophil infiltration were associated with a type 1 immune response and better clinical outcome. Thus, neutrophils driving UTCαß polarization and type 1 immunity are essential for resistance against murine sarcomas and selected human tumors.

HPV16 E7 Genetic Conservation Is Critical to Carcinogenesis.

Although most cervical human papillomavirus type 16 (HPV16) infections become undetectable within 1-2 years, persistent HPV16 causes half of all cervical cancers. We used a novel HPV whole-genome sequencing technique to evaluate an exceptionally large collection of 5,570 HPV16-infected case-control samples to determine whether viral genetic variation influences risk of cervical precancer and cancer. We observed thousands of unique HPV16 genomes; very few women shared the identical HPV16 sequence, which should stimulate a careful re-evaluation of the clinical implications of HPV mutation rates, transmission, clearance, and persistence. In case-control analyses, HPV16 in the controls had significantly more amino acid changing variants throughout the genome. Strikingly, E7 was devoid of variants in precancers/cancers compared to higher levels in the controls; we confirmed this in cancers from around the world. Strict conservation of the 98 amino acids of E7, which disrupts Rb function, is critical for HPV16 carcinogenesis, presenting a highly specific target for etiologic and therapeutic research.

Germline BARD1 variants predispose to mesothelioma by impairing DNA repair and calcium signaling.

We report that ~1.8% of all mesothelioma patients and 4.9% of those younger than 55, carry rare germline variants of the BRCA1 associated RING domain 1 (BARD1) gene that were predicted to be damaging by computational analyses. We conducted functional assays, essential for accurate interpretation of missense variants, in primary fibroblasts that we established in tissue culture from a patient carrying the heterozygous BARD1V523A mutation. We found that these cells had genomic instability, reduced DNA repair, and impaired apoptosis. Investigating the underlying signaling pathways, we found that BARD1 forms a trimeric protein complex with p53 and SERCA2 that regulates calcium signaling and apoptosis. We validated these findings in BARD1-silenced primary human mesothelial cells exposed to asbestos. Our study elucidated mechanisms of BARD1 activity and revealed that heterozygous germline BARD1 mutations favor the development of mesothelioma and increase the susceptibility to asbestos carcinogenesis. These mesotheliomas are significantly less aggressive compared to mesotheliomas in asbestos workers.

Aflatoxin B1 and Epstein-Barr virus-induced CCL22 expression stimulates B cell infection.

Epstein-Barr Virus (EBV) infects more than 90% of the adult population worldwide. EBV infection is associated with Burkitt lymphoma (BL) though alone is not sufficient to induce carcinogenesis implying the involvement of co-factors. BL is endemic in African regions faced with mycotoxins exposure. Exposure to mycotoxins and oncogenic viruses has been shown to increase cancer risks partly through the deregulation of the immune response. A recent transcriptome profiling of B cells exposed to aflatoxin B1 (AFB1) revealed an upregulation of the Chemokine ligand 22 (CCL22) expression although the underlying mechanisms were not investigated. Here, we tested whether mycotoxins and EBV exposure may together contribute to endemic BL (eBL) carcinogenesis via immunomodulatory mechanisms involving CCL22. Our results revealed that B cells exposure to AFB1 and EBV synergistically stimulated CCL22 secretion via the activation of Nuclear Factor-kappa B pathway. By expressing EBV latent genes in B cells, we revealed that elevated levels of CCL22 result not only from the expression of the latent membrane protein LMP1 as previously reported but also from the expression of other viral latent genes. Importantly, CCL22 overexpression resulting from AFB1-exposure in vitro increased EBV infection through the activation of phosphoinositide-3-kinase pathway. Moreover, inhibiting CCL22 in vitro and in humanized mice in vivo limited EBV infection and decreased viral genes expression, supporting the notion that CCL22 overexpression plays an important role in B cell infection. These findings unravel new mechanisms that may underpin eBL development and identify novel pathways that can be targeted in drug development.

STAT3 is a master regulator of epithelial identity and KRAS-driven tumorigenesis.

A dichotomy exists regarding the role of signal transducer and activator of transcription 3 (STAT3) in cancer. Functional and genetic studies demonstrate either an intrinsic requirement for STAT3 or a suppressive effect on common types of cancer. These contrasting actions of STAT3 imply context dependency. To examine mechanisms that underlie STAT3 function in cancer, we evaluated the impact of STAT3 activity in KRAS-driven lung and pancreatic cancer. Our study defines a fundamental and previously unrecognized function of STAT3 in the maintenance of epithelial cell identity and differentiation. Loss of STAT3 preferentially associates with the acquisition of mesenchymal-like phenotypes and more aggressive tumor behavior. In contrast, persistent STAT3 activation through Tyr705 phosphorylation confers a differentiated epithelial morphology that impacts tumorigenic potential. Our results imply a mechanism in which quantitative differences of STAT3 Tyr705 phosphorylation, as compared with other activation modes, direct discrete outcomes in tumor progression.

p53/MDM2 signaling pathway in aging, senescence and tumorigenesis.

A wealth of evidence has emerged that there is an association between aging, senescence and tumorigenesis. Senescence, a biological process by which cells cease to divide and enter a status of permanent cell cycle arrest, contributes to aging and aging-related diseases, including cancer. Aging populations have the higher incidence of cancer due to a lifetime of exposure to cancer-causing agents, reduction of repairing DNA damage, accumulated genetic mutations, and decreased immune system efficiency. Cancer patients undergoing cytotoxic therapies, such as chemotherapy and radiotherapy, accelerate aging. There is growing evidence that p53/MDM2 (murine double minute 2) axis is critically involved in regulation of aging, senescence and oncogenesis. Therefore, in this review, we describe the functions and mechanisms of p53/MDM2-mediated senescence, aging and carcinogenesis. Moreover, we highlight the small molecular inhibitors, natural compounds and PROTACs (proteolysis targeting chimeras) that target p53/MDM2 pathway to influence aging and cancer. Modification of p53/MDM2 could be a potential strategy for treatment of aging, senescence and tumorigenesis.

Oncogenic Fatty Acid Metabolism Rewires Energy Supply Chain in Gastric Carcinogenesis.

BACKGROUND & AIMS: Gastric carcinogenesis develops within a sequential carcinogenic cascade from precancerous metaplasia to dysplasia and adenocarcinoma, and oncogenic gene activation can drive the process. Metabolic reprogramming is considered a key mechanism for cancer cell growth and proliferation. However, how metabolic changes contribute to the progression of metaplasia to dysplasia remains unclear. We have examined metabolic dynamics during gastric carcinogenesis using a novel mouse model that induces Kras activation in zymogen-secreting chief cells. METHODS: We generated a Gif-rtTA;TetO-Cre;KrasG12D (GCK) mouse model that continuously induces active Kras expression in chief cells after doxycycline treatment. Histologic examination and imaging mass spectrometry were performed in the GCK mouse stomachs at 2 to 14 weeks after doxycycline treatment. Mouse and human gastric organoids were used for metabolic enzyme inhibitor treatment. The GCK mice were treated with a stearoyl- coenzyme A desaturase (SCD) inhibitor to inhibit the fatty acid desaturation. Tissue microarrays were used to assess the SCD expression in human gastrointestinal cancers. RESULTS: The GCK mice developed metaplasia and high-grade dysplasia within 4 months. Metabolic reprogramming from glycolysis to fatty acid metabolism occurred during metaplasia progression to dysplasia. Altered fatty acid desaturation through SCD produces a novel eicosenoic acid, which fuels dysplastic cell hyperproliferation and survival. The SCD inhibitor killed both mouse and human dysplastic organoids and selectively targeted dysplastic cells in vivo. SCD was up-regulated during carcinogenesis in human gastrointestinal cancers. CONCLUSIONS: Active Kras expression only in gastric chief cells drives the full spectrum of gastric carcinogenesis. Also, oncogenic metabolic rewiring is an essential adaptation for high-energy demand in dysplastic cells.

Causality and functional relevance of BRCA1 and BRCA2 pathogenic variants in non-high-grade serous ovarian carcinomas.

The identification of causal BRCA1/2 pathogenic variants (PVs) in epithelial ovarian carcinoma (EOC) aids the selection of patients for genetic counselling and treatment decision-making. Current recommendations therefore stress sequencing of all EOCs, regardless of histotype. Although it is recognised that BRCA1/2 PVs cluster in high-grade serous ovarian carcinomas (HGSOC), this view is largely unsubstantiated by detailed analysis. Here, we aimed to analyse the results of BRCA1/2 tumour sequencing in a centrally revised, consecutive, prospective series including all EOC histotypes. Sequencing of n = 946 EOCs revealed BRCA1/2 PVs in 125 samples (13%), only eight of which were found in non-HGSOC histotypes. Specifically, BRCA1/2 PVs were identified in high-grade endometrioid (3/20; 15%), low-grade endometrioid (1/40; 2.5%), low-grade serous (3/67; 4.5%), and clear cell (1/64; 1.6%) EOCs. No PVs were identified in any mucinous ovarian carcinomas tested. By re-evaluation and using loss of heterozygosity and homologous recombination deficiency analyses, we then assessed: (1) whether the eight 'anomalous' cases were potentially histologically misclassified and (2) whether the identified variants were likely causal in carcinogenesis. The first 'anomalous' non-HGSOC with a BRCA1/2 PV proved to be a misdiagnosed HGSOC. Next, germline BRCA2 variants, found in two p53-abnormal high-grade endometrioid tumours, showed substantial evidence supporting causality. One additional, likely causal variant, found in a p53-wildtype low-grade serous ovarian carcinoma, was of somatic origin. The remaining cases showed retention of the BRCA1/2 wildtype allele, suggestive of non-causal secondary passenger variants. We conclude that likely causal BRCA1/2 variants are present in high-grade endometrioid tumours but are absent from the other EOC histotypes tested. Although the findings require validation, these results seem to justify a transition from universal to histotype-directed sequencing. Furthermore, in-depth functional analysis of tumours harbouring BRCA1/2 variants combined with detailed revision of cancer histotypes can serve as a model in other BRCA1/2-related cancers. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

BRAFV600E promotes anchorage-independent growth but inhibits anchorage-dependent growth in hTERT/Cdk4-Immortalized normal human bronchial epithelial cells.

Certain oncogenes, including mutant RAS and BRAF, induce a type of senescence known as oncogene-induced senescence (OIS) in normal cells in a cell-type-specific manner. OIS serves as a barrier to transformation by activated oncogenes. Our previous studies showed that mutant KRASV12 did not efficiently induce OIS in an hTERT/Cdk4-immortalized normal human bronchial epithelial cell line (HBEC3), but it did enhance both anchorage-dependent and anchorage-independent growth. In this study, we investigated whether mutant BRAF, a well-known inducer of OIS, could trigger OIS in HBEC3 cells. We also assessed the impact of mutant BRAF on the growth of HBEC3 cells, as no previous studies have examined this using a normal bronchial epithelial cell line model. We established an HBEC3 cell line, designated as HBEC3-BIN, that expresses mutant BRAFV600E in a doxycycline-regulated manner. Unlike our previous finding that KRASV12 upregulated both pERK and pAKT, mutant BRAFV600E upregulated pERK but not pAKT in HBEC3-BIN cells. Similar to KRASV12, BRAFV600E did not efficiently induce OIS. Interestingly, while BRAFV600E inhibited colony formation in anchorage-dependent conditions, it dramatically enhanced colony formation in anchorage-independent conditions in HBEC3-BIN. In HBEC3 cells without BRAFV600E or KRASV12 expression, p21 was only detected in the cytoplasm, and its localization was not altered by the expression of BRAFV600E or KRASV12. Next-generation sequencing analysis revealed an enrichment of gene sets known to be involved in carcinogenesis, including IL3/JAK/STAT3, IL2, STAT5, and the EMT pathway. Our results indicate that, unlike KRASV12, which promoted both, BRAFV600E enhances anchorage-independent growth but inhibits anchorage-dependent growth of HBEC3. This contrast may result from differences in activation signaling in the downstream pathways. Furthermore, HBEC3 cells appear to be inherently resistant to OIS, which may be partly due to the fact that p21 remains localized in the cytoplasm upon expression of BRAFV600E or KRASV12.

Homeostasis limits keratinocyte evolution.

Recent studies have revealed that normal human tissues accumulate many somatic mutations. In particular, human skin is riddled with mutations, with multiple subclones of variable sizes. Driver mutations are frequent and tend to have larger subclone sizes, suggesting selection. To begin to understand the histories encoded by these complex somatic mutations, we incorporated genomes into a simple agent-based skin-cell model whose prime directive is homeostasis. In this model, stem-cell survival is random and dependent on proximity to the basement membrane. This simple homeostatic skin model recapitulates the observed log-linear distributions of somatic mutations, where most mutations are found in increasingly smaller subclones that are typically lost with time. Hence, neutral mutations are "passengers" whose fates depend on the random survival of their stem cells, where a rarer larger subclone reflects the survival and spread of mutations acquired earlier in life. The model can also maintain homeostasis and accumulate more frequent and larger driver subclones if these mutations (NOTCH1 and TP53) confer relatively higher persistence in normal skin or during tissue damage (sunlight). Therefore, a relatively simple model of epithelial turnover indicates how observed passenger and driver somatic mutations could accumulate without violating the prime directive of homeostasis in normal human tissues.

PARP-1 selectively impairs KRAS-driven phenotypic and molecular features in intrahepatic cholangiocarcinoma.

OBJECTIVE: Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary liver cancer with limited therapeutic options. KRAS mutations are among the most abundant genetic alterations in iCCA associated with poor clinical outcome and treatment response. Recent findings indicate that Poly(ADP-ribose)polymerase1 (PARP-1) is implicated in KRAS-driven cancers, but its exact role in cholangiocarcinogenesis remains undefined. DESIGN: PARP-1 inhibition was performed in patient-derived and established iCCA cells using RNAi, CRISPR/Cas9 and pharmacological inhibition in KRAS-mutant, non-mutant cells. In addition, Parp-1 knockout mice were combined with iCCA induction by hydrodynamic tail vein injection to evaluate an impact on phenotypic and molecular features of Kras-driven and Kras-wildtype iCCA. Clinical implications were confirmed in authentic human iCCA. RESULTS: PARP-1 was significantly enhanced in KRAS-mutant human iCCA. PARP-1-based interventions preferentially impaired cell viability and tumourigenicity in human KRAS-mutant cell lines. Consistently, loss of Parp-1 provoked distinct phenotype in Kras/Tp53-induced versus Akt/Nicd-induced iCCA and abolished Kras-dependent cholangiocarcinogenesis. Transcriptome analyses confirmed preferential impairment of DNA damage response pathways and replicative stress response mediated by CHK1. Consistently, inhibition of CHK1 effectively reversed PARP-1 mediated effects. Finally, Parp-1 depletion induced molecular switch of KRAS-mutant iCCA recapitulating good prognostic human iCCA patients. CONCLUSION: Our findings identify the novel prognostic and therapeutic role of PARP-1 in iCCA patients with activation of oncogenic KRAS signalling.

HBV integrations reshaping genomic structures promote hepatocellular carcinoma.

OBJECTIVE: Hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), mostly characterised by HBV integrations, is prevalent worldwide. Previous HBV studies mainly focused on a few hotspot integrations. However, the oncogenic role of the other HBV integrations remains unclear. This study aimed to elucidate HBV integration-induced tumourigenesis further. DESIGN: Here, we illuminated the genomic structures encompassing HBV integrations in 124 HCCs across ages using whole genome sequencing and Nanopore long reads. We classified a repertoire of integration patterns featured by complex genomic rearrangement. We also conducted a clustered regularly interspaced short palindromic repeat (CRISPR)-based gain-of-function genetic screen in mouse hepatocytes. We individually activated each candidate gene in the mouse model to uncover HBV integration-mediated oncogenic aberration that elicits tumourigenesis in mice. RESULTS: These HBV-mediated rearrangements are significantly enriched in a bridge-fusion-bridge pattern and interchromosomal translocations, and frequently led to a wide range of aberrations including driver copy number variations in chr 4q, 5p (TERT), 6q, 8p, 16q, 9p (CDKN2A/B), 17p (TP53) and 13q (RB1), and particularly, ultra-early amplifications in chr8q. Integrated HBV frequently contains complex structures correlated with the translocation distance. Paired breakpoints within each integration event usually exhibit different microhomology, likely mediated by different DNA repair mechanisms. HBV-mediated rearrangements significantly correlated with young age, higher HBV DNA level and TP53 mutations but were less prevalent in the patients subjected to prior antiviral therapies. Finally, we recapitulated the TONSL and TMEM65 amplification in chr8q led by HBV integration using CRISPR/Cas9 editing and demonstrated their tumourigenic potentials. CONCLUSION: HBV integrations extensively reshape genomic structures and promote hepatocarcinogenesis (graphical abstract), which may occur early in a patient's life.

Stomach microbiota in gastric cancer development and clinical implications.

Gastric cancer (GC) is one of the most common malignancies and a prominent cause of cancer mortality worldwide. A distinctive characteristic of GC is its intimate association with commensal microbial community. Although Helicobacter pylori is widely recognised as an inciting factor of the onset of gastric carcinogenesis, increasing evidence has indicated the substantial involvement of microbes that reside in the gastric mucosa during disease progression. In particular, dysregulation in gastric microbiota could play pivotal roles throughout the whole carcinogenic processes, from the development of precancerous lesions to gastric malignancy. Here, current understanding of the gastric microbiota in GC development is summarised. Potential translational and clinical implications of using gastric microbes for GC diagnosis, prognosis and therapeutics are also evaluated, with further discussion on conceptual haziness and limitations at present. Finally, we highlight that modulating microbes is a novel and promising frontier for the prevention and management of GC, which necessitates future in-depth investigations.

DYRK1B blockade promotes tumoricidal macrophage activity in pancreatic cancer.

OBJECTIVE: Highly malignant pancreatic ductal adenocarcinoma (PDAC) is characterised by an abundant immunosuppressive and fibrotic tumour microenvironment (TME). Future therapeutic attempts will therefore demand the targeting of tumours and stromal compartments in order to be effective. Here we investigate whether dual specificity and tyrosine phosphorylation-regulated kinase 1B (DYRK1B) fulfil these criteria and represent a promising anticancer target in PDAC. DESIGN: We used transplantation and autochthonous mouse models of PDAC with either genetic Dyrk1b loss or pharmacological DYRK1B inhibition, respectively. Mechanistic interactions between tumour cells and macrophages were studied in direct or indirect co-culture experiments. Histological analyses used tissue microarrays from patients with PDAC. Additional methodological approaches included bulk mRNA sequencing (transcriptomics) and proteomics (secretomics). RESULTS: We found that DYRK1B is mainly expressed by pancreatic epithelial cancer cells and modulates the influx and activity of TME-associated macrophages through effects on the cancer cells themselves as well as through the tumour secretome. Mechanistically, genetic ablation or pharmacological inhibition of DYRK1B strongly attracts tumoricidal macrophages and, in addition, downregulates the phagocytosis checkpoint and 'don't eat me' signal CD24 on cancer cells, resulting in enhanced tumour cell phagocytosis. Consequently, tumour cells lacking DYRK1B hardly expand in transplantation experiments, despite their rapid growth in culture. Furthermore, combining a small-molecule DYRK1B-directed therapy with mammalian target of rapamycin inhibition and conventional chemotherapy stalls the growth of established tumours and results in a significant extension of life span in a highly aggressive autochthonous model of PDAC. CONCLUSION: In light of DYRK inhibitors currently entering clinical phase testing, our data thus provide a novel and clinically translatable approach targeting both the cancer cell compartment and its microenvironment.

Optimal age to discontinue long-term surveillance of intraductal papillary mucinous neoplasms: comparative cost-effectiveness of surveillance by age.

OBJECTIVE: Current guidelines recommend long-term image-based surveillance for patients with low-risk intraductal papillary mucinous neoplasms (IPMNs). This simulation study aimed to examine the comparative cost-effectiveness of continued versus discontinued surveillance at different ages and define the optimal age to stop surveillance. DESIGN: We constructed a Markov model with a lifetime horizon to simulate the clinical course of patients with IPMNs receiving imaging-based surveillance. We calculated incremental cost-effectiveness ratios (ICERs) for continued versus discontinued surveillance at different ages to stop surveillance, stratified by sex and IPMN types (branch-duct vs mixed-type). We determined the optimal age to stop surveillance as the lowest age at which the ICER exceeded the willingness-to-pay threshold of US$100 000 per quality-adjusted life year. To estimate model parameters, we used a clinical cohort of 3000 patients with IPMNs and a national database including 40 166 patients with pancreatic cancer receiving pancreatectomy as well as published data. RESULTS: In male patients, the optimal age to stop surveillance was 76-78 years irrespective of the IPMN types, compared with 70, 73, 81, and 84 years for female patients with branch-duct IPMNs <20 mm, =20-29 mm, ≥30 mm and mixed-type IPMNs, respectively. The suggested ages became younger according to an increasing level of comorbidities. In cases with high comorbidity burden, the ICERs were above the willingness-to-pay threshold irrespective of sex and the size of branch-duct IPMNs. CONCLUSIONS: The cost-effectiveness of long-term IPMN surveillance depended on sex, IPMN types, and comorbidity levels, suggesting the potential to personalise patient management from the health economic perspective.

New insights into KLFs and SOXs in cancer pathogenesis, stemness, and therapy.

Despite the development of cancer therapies, the success of most treatments has been impeded by drug resistance. The crucial role of tumor cell plasticity has emerged recently in cancer progression, cancer stemness and eventually drug resistance. Cell plasticity drives tumor cells to reversibly convert their cell identity, analogous to differentiation and dedifferentiation, to adapt to drug treatment. This phenotypical switch is driven by alteration of the transcriptome. Several pluripotent factors from the KLF and SOX families are closely associated with cancer pathogenesis and have been revealed to regulate tumor cell plasticity. In this review, we particularly summarize recent studies about KLF4, KLF5 and SOX factors in cancer development and evolution, focusing on their roles in cancer initiation, invasion, tumor hierarchy and heterogeneity, and lineage plasticity. In addition, we discuss the various regulation of these transcription factors and related cutting-edge drug development approaches that could be used to drug "undruggable" transcription factors, such as PROTAC and PPI targeting, for targeted cancer therapy. Advanced knowledge could pave the way for the development of novel drugs that target transcriptional regulation and could improve the outcome of cancer therapy.

Dissecting the pleiotropic roles of reactive oxygen species (ROS) in lung cancer: From carcinogenesis toward therapy.

Lung cancer is a major cause of morbidity and mortality. The specific pulmonary structure to directly connect with ambient air makes it more susceptible to damage from airborne toxins. External oxidative stimuli and endogenous reactive oxygen species (ROS) play a crucial role in promoting lung carcinogenesis and development. The biological properties of higher ROS levels in tumor cells than in normal cells make them more sensitive and vulnerable to ROS injury. Therefore, the strategy of targeting ROS has been proposed for cancer therapy for decades. However, it is embarrassing that countless attempts at ROS-based therapies have had very limited success, and no FDA approval in the anticancer list was mechanistically based on ROS manipulation. Even compared with the untargetable proteins, such as transcription factors, ROS are more difficult to be targeted due to their chemical properties. Thus, the pleiotropic roles of ROS provide therapeutic potential for anticancer drug discovery, while a better dissection of the mechanistic action and signaling pathways is a prerequisite for future breakthroughs. This review discusses the critical roles of ROS in cancer carcinogenesis, ROS-inspired signaling pathways, and ROS-based treatment, exemplified by lung cancer. In particular, an eight considerations rule is proposed for ROS-targeting strategies and drug design and development.

Effect of vitamin E δ-tocotrienol and aspirin on Wnt signaling in human colon cancer stem cells and in adenoma development in APCmin/+ mice.

In this study, we evaluated the effects of vitamin E δ-tocotrienol (DT3) and aspirin on Wnt signaling in human colon cancer stem cells (CCSCs) and in the prevention of adenoma formation in APCmin/+ mice. We found that knockdown of the adenomatous polyposis coli (APC) gene led to subsequent activation of Wnt signaling in colon epithelial cells (NCM460-APCsiRNA) and induction of ß-catenin and its downstream target proteins c-MYC, cyclin D1, and survivin. When aspirin and DT3 were combined, cell growth and survival were inhibited and apoptosis was induced in colon epithelial cells and in CCSCs. However, DT3 and/or aspirin had little or no effect on control normal colon epithelial cells (NCM460-NCsiRNA). The induction of apoptosis was directly related to activation of caspase 8 and cleavage of BID to truncated BID. In addition, DT3 and/or aspirin-induced apoptosis was associated with cleaved PARP, elevated levels of cytosolic cytochrome c and BAX, and depletion of anti-apoptotic protein BCl-2 in CCSCs. The combination of aspirin and DT3 inhibited the self-renewal capacity, Wnt/ß-catenin receptor activity, and expression of ß-catenin and its downstream targets c-MYC, cyclin D1 and survivin in CCSCs. We also found that treatment with DT3 alone or combined with aspirin significantly inhibited intestinal adenoma formation and Wnt/ ß-catenin signaling and induced apoptosis, compared to vehicle, in APCmin/+ mice. Our study demonstrated a rationale for further investigation of the combination of DT3 and aspirin for colorectal cancer prevention and therapy.