Tumor-Derived Exosomes in Tumor-Induced Immune Suppression.

Exosomes are a class of small membrane-bound extracellular vesicles released by almost all cell types and present in all body fluids. Based on the studies of exosome content and their interactions with recipient cells, exosomes are now thought to mediate "targeted" information transfer. Tumor-derived exosomes (TEX) carry a cargo of molecules different from that of normal cell-derived exosomes. TEX functions to mediate distinct biological effects such as receptor discharge and intercellular cross-talk. The immune system defenses, which may initially restrict tumor progression, are progressively blunted by the broad array of TEX molecules that activate suppressive pathways in different immune cells. Herein, we provide a review of the latest research progress on TEX in the context of tumor-mediated immune suppression and discuss the potential as well as challenges of TEX as a target of immunotherapy.

CCL2/CCR2 signaling in cancer pathogenesis.

Chemokines are a family of small cytokines, which guide a variety of immune/inflammatory cells to the site of tumor in tumorigenesis. A dysregulated expression of chemokines is implicated in different types of cancer including prostate cancer. The progression and metastasis of prostate cancer involve a complex network of chemokines that regulate the recruitment and trafficking of immune cells. The chemokine CCL2 and its main receptor CCR2 have been receiving particular interest on their roles in cancer pathogenesis. The up-regulation of CCL2/CCR2 and varied immune conditions in prostate cancer, are associated with cancer advancement, metastasis, and relapse. Here we reviewed recent findings, which link CCL2/CCR2 to the inflammation and cancer pathogenesis, and discussed the therapeutic potential of CCL2/CCR2 axis in cancer treatment based on results from our group and other investigators, with a major focus on prostate cancer. Video Abstract.

AMP-activated protein kinase: a potential therapeutic target for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive subset of breast carcinomas that lack expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2). Unlike other breast cancer subtypes, targeted therapy is presently unavailable for patients with TNBC. In spite of initial responses to chemotherapy, drug resistance tends to develop rapidly and the prognosis of metastatic TNBC is poor. Hence, there is an urgent need for novel-targeted treatment methods or development of safe and effective alternatives with recognized mechanism(s) of action. AMP-activated protein kinase (AMPK), an energy sensor, can regulate protein and lipid metabolism responding to alterations in energy supply. In the past 10 years, interest in AMPK has increased widely since it appeared as an attractive targeting molecule for cancer therapy. There has been a deep understanding of the possible role of abnormal AMPK signaling pathways in the regulation of growth and survival and the development of drug resistance in TNBC. The increasing popularity of using AMPK regulators for TNBC-targeted therapy is supported by a considerable development in ascertaining the molecular pathways implicated. This review highlights the available evidence for AMPK-targeted anti-TNBC activity of various agents or treatment strategies, with special attention placed on recent preclinical and clinical advances in the manipulation of AMPK in TNBC. The elaborative analysis of these AMPK-related signaling pathways will have a noteworthy impact on the development of AMPK regulators, resulting in efficacious treatments for this lethal disease.

MCP-1 is overexpressed in triple-negative breast cancers and drives cancer invasiveness and metastasis.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer that lacks ER/PR and HER2 receptors. Hence, there is urgency in developing new or novel therapeutic strategies for treatment of TNBC. Our study shows that the Monocyte Chemoattractant Protein-1 (MCP-1) is a marker associated with TNBC and may play a key role in TNBC disease progression. EXPERIMENTAL DESIGN: ELISA method was used to measure secreted MCP-1, and mRNA levels were determined by Real-time PCR in numerous cancer cell lines, representing various breast cancer subtypes. Cellular invasiveness was determined by Boyden chamber assay. RESULTS: Our data show that MCP-1 is upregulated in TNBC cell lines both transcriptionally as well as in secreted protein levels compared to ER-positive luminal cell line, MCF-7. Breast cancer patients, with Basal or Claudin-low subtypes, also showed high expression of MCP-1. MCP-1 treatment induced cell invasion in various breast cancer cell types, without affecting cell proliferation. Small molecule antagonists against Chemokine Receptor 2 (CCR2), cognate receptor for MCP-1 as well as the MAP kinase pathway inhibitor U0126 negatively affected MCP-1 induced MCF-7 cell invasion. This suggests that MCP-1-CCR2 axis may regulate invasiveness via the MAP Kinase pathway. Knocking down MCP-1 decreased cell invasion in TNBC cell line BT-549, along with downregulation of key epithelial to mesenchymal transition markers, N-cadherin and Vimentin. CONCLUSION: Our study suggests that MCP-1 mediated pathways could be potential therapeutic targets for the treatment of TNBC, and could reduce cancer health disparities.

A83-01 inhibits TGF-ß-induced upregulation of Wnt3 and epithelial to mesenchymal transition in HER2-overexpressing breast cancer cells.

PURPOSE: The aim of this study is to investigate the mechanisms of interactions between TGF-ß and Wnt/ß-catenin pathways that induce and regulate EMT and promote breast cancer cells to become resistant to treatment. METHODS: The effect of TGF-ß on Wnt/ß-catenin signaling pathway was examined by using a human Wnt/ß-catenin-regulated cDNA plate array and western blot analysis. The interaction of Twist at promoter of Wnt3 was examined by chromatin immunoprecipitation (ChIP) assay. Secreted Wnt3 level was determined by ELISA assay. RESULTS: HER2-overexpressing breast cancer cells treated with TGF-ß have a reduced response to trastuzumab and exhibited EMT-like phenotype. The TGF-ß-induced EMT in HER2-cells was concordant with upregulation of Wnt3 and ß-catenin pathways. The TGF-ß-induced induction of Wnt3 during EMT was found to be Smad3-dependent. ChIP analysis identified occupancy of Twist at promoter region of Wnt3. Knock-down of Twist by shRNA confirmed the significance of Twist in response to TGF-ß regulating Wnt3 during EMT. Subsequently, TGF-ß-induced matrix metalloproteinases, MMP1, MMP7, MMP9, MMP26, Vascular endothelial growth factors (VEGF), and activation of Wnt/ß-catenin signaling were repressed by the shRNA treatment. TGF-ßR1 ALK5 kinase inhibitor, A83-01 can effectively prevent the TGF-ß-induced Twist and Wnt3. Co-treating A83-01 and trastuzumab inhibited TGF-ß-induced cell invasion significantly in both trastuzumab responsive and resistant cells. CONCLUSIONS: Our data demonstrated an important interdependence between TGF-ß and Wnt/ß-catenin pathways inducing EMT in HER2-overexpressing breast cancer cells. Twist served as a linkage between the two pathways during TGF-ß-induced EMT. A83-01 could inhibit the TGF-ß-initiated pathway interactions and enhance HER2-cells response to trastuzumab treatment.

Proinflammatory Cytokines IL-6 and TNF-α Increased Telomerase Activity through NF-κB/STAT1/STAT3 Activation, and Withaferin A Inhibited the Signaling in Colorectal Cancer Cells.

There are increasing evidences of proinflammatory cytokine involvement in cancer development. Here, we found that two cytokines, IL-6 and TNF-α, activated colorectal cancer cells to be more invasive and stem-like. Combined treatment of IL-6 and TNF-α phosphorylated transcription factors STAT3 in a synergistic manner. STAT3, STAT1, and NF-κB physically interacted upon the cytokine stimulation. STAT3 was bound to the promoter region of human telomerase reverse transcriptase (hTERT). IL-6 and TNF-α stimulation further enhanced STAT3 binding affinity. Stem cell marker Oct-4 was upregulated in colorectal cancer cells upon IL-6 and TNF-α stimulation. Withaferin A, an anti-inflammatory steroidal lactone, inhibited the IL-6- and TNF-α-induced cancer cell invasion and decreased colonosphere formation. Notably, withaferin A inhibited STAT3 phosphorylation and abolished the STAT3, STAT1, and NF-κB interactions. Oct-4 expression was also downregulated by withaferin A inhibition. The binding of STAT3 to the hTERT promoter region and telomerase activity showed reduction with withaferin A treatments. Proinflammatory cytokine-induced cancer cell invasiveness is mediated by a STAT3-regulated mechanism in colorectal cancer cells. Our data suggest that withaferin A could be a promising anticancer agent that effectively inhibits the progression of colorectal cancer.

Lactate, a Neglected Factor for Diabetes and Cancer Interaction.

Increasing body of evidence suggests that there exists a connection between diabetes and cancer. Nevertheless, to date, the potential reasons for this association are still poorly understood and currently there is no clinical evidence available to direct the proper management of patients presenting with these two diseases concomitantly. Both cancer and diabetes have been associated with abnormal lactate metabolism and high level of lactate production is the key biological property of these diseases. Conversely, high lactate contribute to a higher insulin resistant status and a more malignant phenotype of cancer cells, promoting diabetes and cancer development and progression. In view of associations between diabetes and cancers, the role of high lactate production in diabetes and cancer interaction should not be neglected. Here, we review the available evidence of lactate's role in different biological characteristics of diabetes and cancer and interactive relationship between them. Understanding the molecular mechanisms behind metabolic remodeling of diabetes- and cancer-related signaling would endow novel preventive and therapeutic approaches for diabetes and cancer treatment.

Combined inhibition of glycolysis and AMPK induces synergistic breast cancer cell killing.

Targeting glycolysis for cancer treatment has been investigated as a therapeutic method but has not offered a feasible chemotherapeutic strategy. Our aim was to examine whether AMP-activated protein kinase (AMPK), a conditional oncogene, rescues the energetic stress and cytotoxicity induced by 2-deoxyglucose (2-DG), a glycolytic inhibitor, and the related mechanisms. Luciferin/luciferase adenosine triphosphate (ATP) determination, Western analysis, qRT-PCR analyses, MTT growth assay, clonogenic assay, and statistical analysis were performed in this study. 2-DG decreased ATP levels and subsequently activated AMPK, which contribute to intracellular ATP recovery in MCF-7 cells thus exhibiting no apparent cytotoxicity. Compound C, an AMPK inhibitor, further potentiates 2-DG-induced decrease in ATP levels and inhibits their recovery. 2-DG, via AMPK activation, stimulated cAMP response element-binding protein (CREB) phosphorylation and activity and promoted nuclear peroxisome proliferator-activated receptor gamma coactivator-1-beta (PGC-1ß) and estrogen-related receptor α (ERRα) protein expression, leading to augmented mitochondrial biogenesis and expression of fatty acid oxidation (FAO) genes including PPARα, MCAD, CPT1C, and ACO. This metabolic adaptation elicited by AMPK counteracts the ATP-depleting and cancer cell-killing effect of 2-DG. However, 2-DG in combination with AMPK antagonists or small interfering RNA caused a dramatic increase in cytotoxicity in MCF-7 but not in MCF-10A cells. Similarly, when combined with inhibition of CREB/PGC-1ß/ERRα pathway, 2-DG saliently suppressed mitochondrial biogenesis and the expression of FAO genes, depleted ATP production, and enhanced cytotoxicity in cancer cells. Collectively, the combination of 2-DG and AMPK inhibition synergistically enhanced the cytotoxic potential in breast cancer cells with a relative nontoxicity to normal cells and may offer a promising, safe, and effective breast cancer therapeutic strategy.

Vitamin D receptor FokI gene polymorphisms may be associated with colorectal cancer among African American and Hispanic participants.

BACKGROUND: Vitamin D plays a role in cancer tumorogenesis and acts through the vitamin D receptor (VDR). Although African Americans have the lowest serum vitamin D levels, supplementation has not yielded a significant improvement in cancer. Gene polymorphisms in VDR may play a role. There is a dearth of information on VDR gene polymorphisms and colorectal cancer (CRC) among under-represented ethnic groups. In this study, the authors examined whether VDR gene single nucleotide polymorphisms (SNPs) were associated with CRC in predominately African American and Hispanic study participants. METHODS: Blood samples were collected from 378 participants, including a group of 78 patients with CRC (cases), a group of 230 noncancer participants without polyps (controls without polyps), and a group of 70 noncancer participants with polyps (controls with polyps). The 4 polymorphic SNPs in VDR (FokI, BsmI, TaqI, and ApaI) were assessed using the polymerase chain reaction-restriction fragment length polymorphism method. RESULTS: There was a significant association of the VDR-FokI FF genotype with CRC cases (odds ratio, 2.9; P= .036) compared with the controls without polyps. The most common VDR-FokI genotype in the overall study population was the FF genotype (46%). However, upon breakdown by ethnicity, the FF genotype was the most common in African American participants (61%), and the Ff genotype was the most common in Hispanic/Latino participants (49%). When the association was assessed in a multivariate model, there was no significant association with any VDR polymorphism and CRC cases (P> .05). The other 3 polymorphic variants of VDR (BsmI, TaqI, and ApaI) were not associated with CRC. CONCLUSIONS: The results from this study suggest that genetic variation of the VDR-FokI SNPs may influence CRC risk, particularly in African American cohorts.

Activation of Akt1 accelerates carcinogen-induced tumorigenesis in mammary gland of virgin and post-lactating transgenic mice.

BACKGROUND: Data from in vivo and in vitro studies suggest that activation of Akt regulates cell survival signaling and plays a key role in tumorigenesis. Hence, transgenic mice were created to explore the oncogenic role of Akt1 in the development of mammary tumors. METHODS: The transgenic mice were generated by expressing myristoylated-Akt1 (myr-Akt1) under the control of the MMTV-LTR promoter. The carcinogen 7, 12 dimethyl-1,2-benzanthracene (DMBA) was used to induce tumor formation. RESULTS: The MMTV driven myr-Akt1 transgene expression was detected primarily in the mammary glands, uterus, and ovaries. The expression level increased significantly in lactating mice, suggesting that the response was hormone dependent. The total Akt expression level in the mammary gland was also higher in the lactating mice. Interestingly, the expression of MMTVmyr-Akt1 in the ovaries of the transgenic mice caused significant increase in circulating estrogen levels, even at the post-lactation stage. Expression of myr-Akt1 in mammary glands alone did not increase the frequency of tumor formation. However, there was an increased susceptibility of forming mammary tumors induced by DMBA in the transgenic mice, especially in mice post-lactation. Within 34 weeks, DMBA induced mammary tumors in 42.9% of transgenic mice post-lactation, but not in wild-type mice post-lactation. The myr-Akt1 mammary tumors induced by DMBA had increased phosphorylated-Akt1 and showed strong expression of estrogen receptor (ERα) and epidermal growth factor receptor (EGFR). In addition, Cyclin D1 was more frequently up-regulated in mammary tumors from transgenic mice compared to tumors from wild-type mice. Overexpression of Cyclin D1, however, was not completely dependent on activated Akt1. Interestingly, mammary tumors that had metastasized to secondary sites had increased expression of Twist and Slug, but low expression of Cyclin D1. CONCLUSIONS: In summary, the MMTVmyr-Akt1 transgenic mouse model could be useful to study mechanisms of ER-positive breast tumor development.

Correlates of perceived risk of developing cancer among African-Americans in South Los Angeles.

There are differences in cancer-risk perception among racial/ethnic groups that may affect health risk behaviors. Using a community partnered-participatory research approach, we conducted a survey on cancer screening, risk behaviors, and related knowledge/attitudes within 11 churches in South Los Angeles with predominantly African-American parishioners. This analysis examines correlates of perceived risk of developing cancer among 755 African American adults. Almost 15 % of participants indicated higher perceived risk for cancer compared to the average man/woman of the same age, 38 % indicated same risk, whereas 48 % perceived lower risk. Sixty-nine individuals (9 %) reported a cancer history and 63 % reported at least one blood relative with cancer. Controlling for demographic characteristics and healthcare access, participants who reported higher risk of cancer had higher level of cancer-related knowledge; were current and ex-smokers; had poorer health status; had a blood relative with cancer; had a cancer history; and had discussed their risk of cancer with their doctor. The bivariate association between high perceived cancer risk and lack of exercise and obesity disappeared after adjusting for demographic characteristics and perceived health status. Our data suggest that a substantial proportion of African Americans in South Los Angeles may underestimate their cancer risk. Additionally, lack of exercise and obesity are not recognized as independent cancer risk factors as much as smoking and personal and family history of cancer. Next steps will be to inform participating churches about our findings and explore their interest in taking steps to reduce health risk behaviors among their parishioners.

Inflammatory Cytokines Associated with Obesity, Type-2 Diabetes, and Hypertension Exacerbate Breast Cancer Risk in Underserved African American and Latin American Women.

Background: Comorbid chronic diseases, such as obesity, Type-2 Diabetes (T2D), and hypertension (HTN), are major public health issues and highly prevalent among underserved African Americans (AA) and Latin Americans (LA). Elevated inflammatory cytokines are underlying processes in comorbidities (obesity, T2D, and HTN) that could contribute to tumorigenesis and adverse cancer outcomes. Methods: A panel of 19 cytokines was measured by Luminex assay from 570 AA and LA women's serum samples. The comorbidities and breast cancer information were extracted from our existing clinical database. Comorbidity-associated cytokines were identified by linear regression analysis, and the odds ratios of increasing cytokines for breast cancer were evaluated by Logistic regression. Results: Women with obesity, T2D, and HTN elevated specific groups of cytokines. EGF, MCP1, MDC, MIP-1b, and Groα were independent of T2D and HTN significantly associated with obesity. TGFß1 and TGFß2 were T2D-associated cytokines, and MIB-1b, TNFα, and VEGFα were HTN-associated cytokines. Among those comorbidity-associated cytokines, CXCL1, CCL4, CXCL10, TNFα, TGFß1, and TGFß2 were also significantly associated with breast cancer diagnosed at age < 50. Two or more comorbidities further increased the levels of Groα, MIP-1b, TNFα, and TGFßs. Conclusions: Comorbidity-associate cytokines could augment the risk of breast cancer for AA and LA women.

Correction: Wu et al. Expression of MALAT1 Promotes Trastuzumab Resistance in HER2 Overexpressing Breast Cancers. Cancers 2020, 12, 1918.

In the original publication, there was a mistake in Figure 4B as published [...].

Enhanced Chemoprevention of Prostate Cancer by Combining Arctigenin with Green Tea and Quercetin in Prostate-Specific Phosphatase and Tensin Homolog Knockout Mice.

The low bioavailability of most phytochemicals limits their anticancer effects in humans. The present study was designed to test whether combining arctigenin (Arc), a lignan mainly from the seed of Arctium lappa, with green tea (GT) and quercetin (Q) enhances the chemopreventive effect on prostate cancer. We performed in vitro proliferation studies on different cell lines. We observed a strong synergistic anti-proliferative effect of GT+Q+Arc in exposing androgen-sensitive human prostate cancer LNCaP cells. The pre-malignant WPE1-NA22 cell line was more sensitive to this combination. No cytotoxicity was observed in normal prostate epithelial PrEC cells. For an in vivo study, 3-week-old, prostate-specific PTEN (phosphatase and tensin homolog) knockout mice were treated with GT+Q, Arc, GT+Q+Arc, or the control daily until 16 weeks of age. In vivo imaging using prostate-specific membrane antigen (PSMA) probes demonstrated that the prostate tumorigenesis was significantly inhibited by 40% (GT+Q), 60% (Arc at 30 mg/kg bw), and 90% (GT+Q+Arc) compared to the control. A pathological examination showed that all control mice developed invasive prostate adenocarcinoma. In contrast, the primary lesion in the GT+Q and Arc alone groups was high-grade prostatic intraepithelial neoplasia (PIN), with low-grade PIN in the GT+Q+Arc group. The combined effect of GT+Q+Arc was associated with an increased inhibition of the androgen receptor, the PI3K/Akt pathway, Ki67 expression, and angiogenesis. This study demonstrates that combining Arc with GT and Q was highly effective in prostate cancer chemoprevention. These results warrant clinical trials to confirm the efficacy of this combination in humans.

Proteome-wide association study and functional validation identify novel protein markers for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains a lethal malignancy, largely due to the paucity of reliable biomarkers for early detection and therapeutic targeting. Existing blood protein biomarkers for PDAC often suffer from replicability issues, arising from inherent limitations such as unmeasured confounding factors in conventional epidemiologic study designs. To circumvent these limitations, we use genetic instruments to identify proteins with genetically predicted levels to be associated with PDAC risk. Leveraging genome and plasma proteome data from the INTERVAL study, we established and validated models to predict protein levels using genetic variants. By examining 8,275 PDAC cases and 6,723 controls, we identified 40 associated proteins, of which 16 are novel. Functionally validating these candidates by focusing on 2 selected novel protein-encoding genes, GOLM1 and B4GALT1, we demonstrated their pivotal roles in driving PDAC cell proliferation, migration, and invasion. Furthermore, we also identified potential drug repurposing opportunities for treating PDAC. SIGNIFICANCE: PDAC is a notoriously difficult-to-treat malignancy, and our limited understanding of causal protein markers hampers progress in developing effective early detection strategies and treatments. Our study identifies novel causal proteins using genetic instruments and subsequently functionally validates selected novel proteins. This dual approach enhances our understanding of PDAC etiology and potentially opens new avenues for therapeutic interventions.

Comparing perceived and test-based knowledge of cancer risk and prevention among Hispanic and African Americans: an example of community participatory research.

BACKGROUND: Most theoretical formulations acknowledge that knowledge and awareness of cancer screening and prevention recommendations significantly influence health behaviors. This study compares perceived knowledge of cancer prevention and screening with test-based knowledge in a community sample. We also examine demographic variables and self-reported cancer screening and prevention behaviors as correlates of both knowledge scores, and consider whether cancer related knowledge can be accurately assessed using just a few, simple questions in a short and easy-to-complete survey. METHODS: We used a community-partnered participatory research approach to develop our study aims and a survey. The study sample was composed of 180 predominantly African American and Hispanic community individuals who participated in a full-day cancer prevention and screening promotion conference in South Los Angeles, California, on July 2011. Participants completed a self-administered survey in English or Spanish at the beginning of the conference. RESULTS: Our data indicate that perceived and test-based knowledge scores are only moderately correlated. Perceived knowledge score shows a stronger association with demographic characteristics and other cancer related variables than the test-based score. Thirteen out of twenty variables that are examined in our study showed a statistically significant correlation with the perceived knowledge score, however, only four variables demonstrated a statistically significant correlation with the test-based knowledge score. CONCLUSION: Perceived knowledge of cancer prevention and screening was assessed with fewer items than test-based knowledge. Thus, using this assessment could potentially reduce respondent burden. However, our data demonstrate that perceived and test-based knowledge are separate constructs.

The clinical utilization of circulating cell free DNA (CCFDNA) in blood of cancer patients.

Qualitative and quantitative testing of circulating cell free DNA (CCFDNA) can be applied for the management of malignant and benign neoplasms. Detecting circulating DNA in cancer patients may help develop a DNA profile for early stage diagnosis in malignancies. The technical issues of obtaining, using, and analyzing CCFDNA from blood will be discussed.

Advancing Cancer Research: Insights and Innovations in Pathogenesis and Targeted Therapies.

Cancer is a global health challenge that continues to affect millions of people, despite extensive research efforts [...].

Genetic variants in African-American and Hispanic patients with breast cancer.

Breast cancer is a disease with significant health disparity affecting mortality in minority women. The present study examined the genetic makeup of breast cancers in African-American and Hispanic/Latinx patients to determine specific genetic mutations associated with breast cancer in the minority population from South Los Angeles, United States. Whole-exome sequencing was performed on DNA extracted from breast cancer tumor biopsies collected from 13 African-American and 15 Hispanic women and 8 matched-normal samples for each ethnic category. The results were analyzed using Ensemble Variant Effect Predictor and Mutation Significance. Additionally, a comparative analysis with The Cancer Genome Atlas data was provided. Our data revealed somatic mutations in genes such as SET domain containing (lysine methyltransferase) 8, serine protease 1 and AT-rich interaction domain 1B (ARID1B) and known breast cancer genes, such as BRCA1/2, TP53 and the DNA damage response genes across all ethnicities. Additionally, Hispanic patients had BRCA1 associated RING domain 1B (BARD1) variants, while African-American patients had higher numbers of nonsynonymous variants in the RAD51 paralog B (RAD51B), ARID1B and X-ray repair cross complementing 3 (XRCC3) genes. In addition, our patients exhibited mutational signature enrichment that indicated DNA homologous recombination repair deficiencies. Therefore, African-American and Hispanic breast cancer samples showed considerable overlap in breast cancer genetic mutations. However, there are differences in specific genetic variants in TP53, BRCA1/2, BARD1 or ARID1B, which will require further study of their role in tumorigenesis.