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Lithium is a fundamental raw material for the production of rechargeable batteries. The technology currently in use for lithium salts recovery from continental brines entails the evaporation of huge water...

Glioma-associated oncogene family zinc finger 2 (Gli2), a key component of the hedgehog signaling pathway, has been previously demonstrated to promote the malignant properties of prostate cancer in vitro. However, the role of Gli2 in the development of castration-resistant prostate cancer (CRPC) has yet to be fully elucidated. In the present study, Gli2 expression was knocked down in androgen-responsive prostate cancer cells using an inducible Gli2 short hairpin RNA. Suppression of Gli2 expression resulted in significant reduction of cell viability, increased the proportion of cells in the G0/G1 phases of the cell cycle and reduced the expression of genes associated with cell cycle progression. Gli2 knockdown sensitized both androgen-dependent and -independent prostate cancer cells to the antiandrogen drug Casodex and prevented the outgrowth of LNCaP prostate cancer cells. In addition, Gli2 knockdown significantly suppressed the development of CRPC in a LNCaP xenograft mouse model, which was reversed by the re-expression of Gli2. In conclusion, to the best of our knowledge, the present study was the first occasion in which the essential role of Gli2 in the development of CRPC was demonstrated, providing a potential therapeutic target for the intervention of CRPC.

Deregulation of apoptosis is central to cancer progression and a major obstacle to effective treatment. The Bcl-2 gene family members play important roles in the regulation of apoptosis and are frequently altered in cancers. One such member is pro-apoptotic protein Bcl-2-related Ovarian Killer (BOK). Despite its critical role in apoptosis, the regulation of BOK expression is poorly understood in cancers. Here, we discovered that miR-296-5p regulates BOK expression by binding to its 3'-UTR in breast cancers. Interestingly, miR-296-5p also regulates the expression of anti-apoptotic protein myeloid cell leukemia 1 (Mcl-1), which is highly expressed in breast cancers. Our results reveal that Mcl-1 and BOK constitute a regulatory feedback loop as ectopic BOK expression induces Mcl-1, whereas silencing of Mcl-1 results in reduced BOK levels in breast cancer cells. In addition, we show that silencing of Mcl-1 but not BOK reduced the long-term growth of breast cancer cells. Silencing of both Mcl-1 and BOK rescued the effect of Mcl-1 silencing on breast cancer cell growth, suggesting that BOK is important for attenuating cell growth in the absence of Mcl-1. Depletion of BOK suppressed caspase-3 activation in the presence of paclitaxel and in turn protected cells from paclitaxel-induced apoptosis. Furthermore, we demonstrate that glycogen synthase kinase (GSK3) α/β interacts with BOK and regulates its level post-translationally in breast cancer cells. Taken together, our results suggest that fine tuning of the levels of pro-apoptotic protein BOK and anti-apoptotic protein Mcl-1 may decide the fate of cancer cells to either undergo apoptosis or proliferation.

To understand potential molecular mechanisms that drive hepatocellular carcinoma (HCC) progression, we performed RNA sequencing from paired adjacent non-tumor liver and HCC tumor tissues of nine local HCC patients which revealed significant involvement of a gene coding for Six Transmembrane Epithelial Antigen of Prostate 2 (STEAP2) protein. STEAP2 is a metalloreductase involved in the reduction and indirectly, uptake, of iron and copper ions. We found significantly higher levels of total copper in HCC tissues than those in paired adjacent non-tumor tissues. The upregulation of STEAP2 expression in HCC was confirmed at its protein level and in TCGA and other published HCC gene expression datasets. Hepatic copper overload is associated with Wilson's disease and a known risk factor for HCC, therefore, we hypothesize that STEAP2 upregulation and copper accumulation contribute to HCC progression. Paired HCC and adjacent non-tumor tissues were collected for RNA sequencing, metal ion measurement, and measurements of STEAP2 levels with RT-qPCR and Western blot. Public HCC datasets were queried for STEAP2 expression in HCC and non-tumor tissues. HCC cell lines with knockdown (KD) and overexpression (OE) of STEAP2 were created to perform mechanistic studies including measurements of copper levels and MAP kinase activities, cell proliferation, migration, and anchorage independent growth in vitro and tumor growth in vivo. STEAP2 is significantly upregulated in various HCC gene expression datasets; its expression is positively associated with tumor grade. STEAP2 KD in HCC cell lines decreased cell growth, migration, invasion, and xenograft tumor growth, while STEAP2 OE showed opposite effects. STEAP2 KD in HCC cells also reduced intracellular copper levels and activation of stress-activated MAP kinases including p38 and JNK. Treatment with copper rescued the reduced HCC cell migration due to STEATP2 KD and activated p38 and JNK. Furthermore, treatment with p38 or JNK inhibitors significantly inhibited cell migration. Thus, STEAP2 appears to play a malignant-promoting role in HCC cells by driving migration/invasion via increased copper levels and MAP kinase activities. Our study uncovered a novel molecular mechanism contributing to HCC malignancy and a potential therapeutic target for HCC treatment. Citation Format: Carla R. Zeballos, Acarizia Easley, Hakim Bouamar, Guixi Zheng, Xiang Gu, Yang Junhua, Yidong Chen, Francisco Cigarroa, LuZhe Sun. STEAP2 is upregulated and necessary for hepatocellular carcinoma progression via increased copper levels and stress-activated MAP kinase activity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3750.

Introduction: Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide and the third leading cause of cancer related mortality. The incidence and mortality rates of HCC are two times higher in Latinos than in the general population in the US and are the highest in Latinos from the South Texas region. The genetic and epigenetic events associated with the increased incidence of HCC in this population are still unclear. Increasing evidence suggests that integrins are one of the most important receptors for cell metastasis including integrin α6β1 and α6β4. However, few studies have focused on the function of integrin alpha 6 (ITGA6) in the tumorigenesis and progression of HCC. We aim to investigate the expression and potential roles of ITGA6 in HCC. Materials and Methods: Paired HCC tissues and adjacent non-tumor tissues were collected for RNA sequencing. ITGA6 RNA and protein expression levels were evaluated by RNA sequencing, RT-qPCR, Western blot and immunohistochemistry. HCC cell lines (SNU398 and Huh7) were transiently transfected with two ITGA6siRNAs and stably transfected with an ITGA6 shRNA lentivector. These cell lines were used for assays testing the effects of ITGA6 knockdown on HCC cell proliferation, migration and anchorage independent growth. Results: Analysis of RNA sequencing data indicated that the expression of ITGA6 increased 4-fold in HCC tumor tissues compared to adjacent non-tumor tissues, which was validated by RT-qPCR. Western blotting also confirmed increased expression of ITGA6 in the tumor tissues. The knockdown of ITGA6 by siRNAs and shRNA was confirmed with Western blot and qRT-PCR. ITGA6 knockdown significantly decreased proliferation, migration and anchorage independent growth of HCC cell lines. Conclusions: ITGA6 is upregulated in HCC tumors in Latinos patients. ITGA6 may play a malignant-promoting role in HCC cells. Our studies provided new insights into the molecular mechanisms that drive HCC progression and potential therapeutic targets for treating patients with HCC including South Texas Latino patients. Citation Format: Guixi Zheng, Carla Zeballos, Hakim Bouamar, Matyas Cserhati, Francisco G Cigarroa, Lu-zhe Sun. RNA interference reveals tumor promoting roles of integrin alpha 6 (ITGA6) in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4642.

Introduction: Hepatocellular carcinoma (HCC) is the most common type of liver cancer in adults and the third most common cause of cancer death worldwide; while incidence and mortality rates are two times higher in Latinos, incidence rates are the highest among Latinos in the South Texas region. The genetic and epigenetic events associated with the increased incidence of HCC in this population are largely unknown. We performed whole genome RNA sequencing in paired HCC tumor and adjacent non-tumor tissue total RNA from nine South Texas Latino patients. Analysis of differentially expressed genes revealed significant alterations in pathways associated with oxidative stress; most importantly, we found that the expression of STEAP2 (Six Transmembrane Epithelial Antigen of the Prostate 2) is increased five-fold in HCC tumor tissue compared to adjacent non-tumor tissue. In comparison to a non-Latino population, this finding was unique to South Texas Latinos. STEAP2 is a metalloreductase of iron and copper; reduced iron and copper ions can mediate the production of hydroxyl radicals resulting in increased oxidative stress, which can cause DNA damage and lipid peroxidation. We aim to prove that STEAP2 through regulation of iron and copper homeostasis, and an increase in oxidative stress, will lead to malignant transformation of hepatocytes resulting in tumor progression of HCC, including in obese hosts. Material and Methods: Latino paired HCC and adjacent non-tumor tissues were collected for RNA sequencing, metal ion measurement and oxidative stress markers. STEAP2 RNA and protein expression levels in Latino and Caucasian samples were evaluated by RT-PCR, Western blot, and immunohistochemistry. HCC cell lines (SNU398 and HUH7) with knockdown (KD) and overexpression (OE) of STEAP2 were created to examine the proliferation, migration, anchorage independent growth, and oxidative stress in vitro. Results: Analysis of RNA sequencing data demonstrated the overexpression of STEAP2 in HCC tumors in Latino patients, which were validated by RT-PCR and Western blot data. Lipid peroxidation product, 4-hydroxynonenal, and copper levels were higher in HCC tumor vs. adjacent tissue. KD of STEAP2 in the HCC cell lines decreased proliferation, migration and anchorage independent growth, while OE of STEAP2 increase migration and anchorage independent growth but not proliferation. Conclusions: STEAP2 is specifically overexpressed in HCC tumors in Latinos in comparison to HCC tumors in non-Latino whites and appears to play a malignant-promoting role in HCC cells. Further studies on the role of STEAP2 as a novel tumor promoter in HCC and the mechanisms by which it promotes carcinogenesis are underway. The proposed studies will likely yield mechanistic insights into the molecular mechanisms that drive HCC development and progression in South Texas Latinos and potential therapeutic targets. Citation Format: Carla Zeballos, Hakim Bouamar, Guixi Zheng, Xiang Gu, Yidong Chen, Francisco G. Cigarroa, Lu-Zhe Sun. Hepatocellular carcinoma in the South Texas Latino population: Implications of STEAP2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2424.

Deregulation of apoptosis is central to cancer progression and a major obstacle to effective treatment. The Bcl-2 gene family members play important roles in the regulation of apoptosis and are frequently altered in cancers. One such member is Bcl-2-related Ovarian Killer (BOK), which is a pro-apoptotic protein. Despite its critical role in apoptosis, the regulation of BOK expression is poorly understood in cancers. Here, we discovered that miR-296-5p, regulates BOK expression by binding to its 3’UTR in breast cancers. Furthermore, we show that depletion of BOK by either miR-296-5p or siRNA against BOK protected breast cancer cells from undergoing paclitaxel-induced apoptosis. Interestingly, miR-296-5p also regulates the expression of Mcl-1, which is an anti-apoptotic protein and is highly expressed in breast cancers. Our results reveal that Mcl-1 is important for suppression of BOK function as ectopic BOK expression induced Mcl-1, while silencing of BOK resulted in reduced Mcl-1 levels in breast cancer cells. In addition, we show that specific silencing of Mcl-1 reduced the long-term growth of breast cancer cells, whereas BOK inhibition didn’t have any effect on the growth of breast cancer cells. Surprisingly, silencing of both Mcl-1 and BOK rescued the effect of Mcl-1 silencing on breast cancer cell growth, suggesting that BOK is important for attenuating cell growth in the absence of Mcl-1, and also showing a tight feedback regulatory loop between BOK and Mcl-1 in breast cancer cells. Furthermore, we demonstrated that BOK protein level is regulated post-translationally by GSK3α and to some extent GSK3β as GSK3 inhibitor (CHIR99021) or silencing of GSK3 significantly increased BOK protein levels in breast cancer cells. Notably, we found that Mcl-1 interacts with GSK3α/β and silencing of Mcl-1 using siRNA significantly attenuated endogenous GSK3α/β levels in breast cancer cells. Taken together, our results suggest that fine tuning (either post-transcriptionally by miR-296-5p or post-translationally by GSK3) of the levels of pro-apoptotic protein BOK and anti-apoptotic protein Mcl-1 decide the fate of cancer cells to either undergo Apoptosis or proliferation. Citation Format: Benjamin Chidi Onyeagucha, Panneerdoss Subbarayalu, Subapriya Rajamanickam, Nourhan Abdelfattah, Santosh Timilsina, Rosa M. Guzman, Carla Zeballos, Vijay Eedunuri, Sanjay Bansal, Hima Bansal, Tabrez A. Mohammad, Yidong Chen, Manjeet K. Rao. Novel regulatory mechanisms for Bcl2-related Ovarian Killer (BOK) expression in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2336. doi:10.1158/1538-7445.AM2017-2336

Introduction: The incidence of hepatocellular carcinoma (HCC) in Hispanics is three times higher than non-Hispanic whites, and even higher in South Texas (STX) Hispanics. This is attributed to a higher prevalence of hepatitis C, diabetes, obesity and perhaps genetic and epigenetic alterations. Knowledge regarding genetic alterations in Hispanics is sparse as demonstrated by the lack of Hispanics with HCC in The Cancer Genome Atlas (TCGA). Therefore, our group sequenced paired adjacent liver and HCC tumor samples from STX Hispanics, which highlighted a gene over-expressed in tumors of Hispanics, called the Six Transmembrane Epithelial Antigen of the Prostate 2 (STEAP2). STEAP2 is a metalloreductase of iron and copper and is implicated in increased iron and reactive oxygen species in the liver which can lead to the progression of inflammation and cirrhosis. STEAP2 may play an important oncogenic role in HCC, especially in the setting of obesity. We propose to test the hypothesis that overexpression of STEAP2 will lead to malignant property in HCC cells resulting in enhanced proliferation, survival, invasiveness, and eventually development of HCC, especially in obese hosts. Methods: Hispanic paired tissue continues to be collected from our institution for RNA sequencing and establishment of Hispanic HCC cell lines. STEAP2 RNA and protein expression levels in Hispanic paired samples versus Caucasian paired samples were evaluated by RT-PCR, Western blot, and immunohistochemistry. Knockdown and overexpression of STEAP2 were established in HCC cell lines and in primary Hispanic HCC cell lines to examine the effects on iron levels, oxidative stress, proliferation, invasiveness, apoptosis and cell cycle in vitro. Results: Hispanic HCC RNA sequencing data compared to TCGA HCC RNA sequencing data (no Hispanics) demonstrated the overexpression of STEAP2 in HCC tumors in Hispanic patients, which were validated by RT-PCR data and Western blot data. Lipid peroxidation product, 4-hydroxynonenal, and copper levels were higher in HCC tumor versus adjacent tissue. Iron levels were higher in adjacent tissue versus tumor tissue in Hispanics. Knockdown of STEAP2 in SNU398 cells decreased proliferation and migration, while in HUH7 cells STEAP2 knockdown only decreased migration. Conclusions: STEAP2 is specifically overexpressed in HCC tumors in Hispanics in comparison to HCC tumors in non-Hispanic whites and appears to play a malignant-promoting role in HCC cells. Further studies to establish the role of STEAP2 as a tumor promoter in HCC and the mechanisms by which it promotes carcinogenesis are underway. The proposed studies will likely yield mechanistic insights into the molecular mechanisms that drive HCC development and progression in South Texas Hispanics and potential therapeutic targets involving STEAP2-mediated metal ion metabolism and oxidative stress. Citation Format: Carla R. Zeballos, Hakim Bouamar, Xiang Gu, Yidong Chen, Francisco G. Cigarroa, LuZhe Sun. The role of six transmembrane epithelial antigen of the prostate 2 in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5425. doi:10.1158/1538-7445.AM2017-5425

Background: Left heart mechanical circulatory support (MCS) through the left chest via the pulmonary vein and descending thoracic aorta is a good option for patients with an inaccessible anterior mediastinum and/or poor peripheral access. Materials and Methods: We report the case of a 19-year-old small female with a newly discovered bulky primary mediastinal diffuse large B-cell lymphoma (PMBL) who developed refractory inverted Takotsubo cardiomyopathy (TC) with cardiogenic shock. Results: Temporary MCS was implemented in order to stabilize the patient and proceed with a chemotherapy treatment. Given the patient's oncologic “frozen” mediastinum and the presence of poor peripheral arterial access, the left heart temporary MCS was successfully implanted through a left mini-thoracotomy via the left inferior pulmonary vein and descending thoracic aorta. Conclusions: This is the first report of temporary MCS to treat inverted TC and diffuse PMBL. (J Card Surg 2012;27:119–121)