CDK4/6 Inhibition With Lerociclib is a Potential Therapeutic Strategy for the Treatment of Pediatric Sarcomas.

BACKGROUND: Sarcomas are a heterogenous collection of bone and soft tissue tumors. The heterogeneity of these tumors makes it difficult to standardize treatment. CDK 4/6 inhibitors are a family of targeted agents which limit cell cycle progression and have been shown to be upregulated in sarcomas. In the current preclinical study, we evaluated the effects of lerociclib, a CDK4/6 inhibitor, on pediatric sarcomas in vitro and in 3D bioprinted tumors. METHODS: The effects of lerociclib on viability, proliferation, cell cycle, motility, and stemness were assessed in established sarcoma cell lines, U-2 OS and MG-63, as well as sarcoma patient-derived xenografts (PDXs). 3D printed biotumors of each of the U-2 OS, MG-63, and COA79 cells were utilized to study the effects of lerociclib on tumor growth ex vivo. RESULTS: CDK 4/6, as well as the intermediaries retinoblastoma protein (Rb) and phosphorylated Rb were identified as targets in the four sarcoma cell lines. Lerociclib treatment induced cell cycle arrest, decreased proliferation, motility, and stemness of sarcoma cells. Treatment with lerociclib decreased sarcoma cell viability in both traditional 2D culture as well as 3D bioprinted microtumors. CONCLUSIONS: Inhibition of CDK 4/6 activity with lerociclib was efficacious in traditional 2D sarcoma cell culture as well as in 3D bioprints. Lerociclib holds promise and warrants further investigation as a novel therapeutic strategy for management of these heterogenous groups of tumors.

Molecular Docking and In Vivo Biological Studies of Sodium Salt of 3-(4-Methyl-2-oxo-2-H-quinoline-7-yloxy)-3-phenylacrylic Acid As Anticancer Agent.

Quinoline derivatives possess several therapeutic properties. Aim: studying the anticancer effect of 3-(4-methyl-2-oxo-2-H-quinoline-7-yloxy)-3-phenylacrylic acid's sodium solution on the Ehrlich ascites carcinoma (EAC). Median lethal dose (LD50) and dose response curve was determined for sodium salt solution of 3-(4-methyl-2-oxo-2-H-quinoline-7-yloxy)-3-phenylacrylic acid, then diving a group of one hundred Swiss albino mice, which are all females, into five groups: group 1: (negative control) where intraperitoneally injected with saline into mice for 10 successive days; group 2 (positive control), also namely (EAC-bearing group): where the EAC cells were intraperitoneally injected into mice (2.5 × 106 cells/mouse) only one time on the first day; group 3 which is defined as the (therapeutic group) where the Na+ salt of the synthetic compound was injected into the peritoneum of the mice (2.5 mg/kg) the very first day after the injection of the EAC, then the compound was injected every two days for a period of 10 days; group 4 which is the (preventive group) where the sodium salt of the synthetic compound (2.5 mg/kg) was injected in the peritoneum of the mice the day before the injection of the EAC, then the compound was successively injected every day for a period of ten days; and group 5 which is the (drug group) in which mice were repeatedly injected) in their peritoneum with the sodium salt of the synthetic compound (2.5 mg/kg on a daily basis over a period of ten days. On the eleventh day of the trial, EAC cells were harvested from each mouse in a heparinized saline, in addition to blood samples, liver and kidney tissues which are also collected. Molecular docking showed that compound's sodium salt was docked into (PDB: 2R7G) and (PDB: 2R3I), which are the retinoblastoma protein receptor and the cyclin D-1 receptor respectively. Compared to those in the positive control group, mice in both the therapeutic and preventive groups, has shown a significant decrease in MDA, cyclin D-1 levels in the tissues of both liver and kidney tissues, in addition to the serum ALT, AST, CK-MB, and LDH activities, and the serum urea and creatinine concentration. However, mice in the formerly mentioned groups, both therapeutic and preventive groups, have shown an increase in the serum albumin, total protein, retinoblastoma protein in both liver and kidney tissues as well as the total antioxidant capacity, when compared to mice in the positive control group. It is worth mentioning that histopathological findings have confirmed that. Sodium salt of 3-(4-methyl-2-oxo-2H-quinoline-7-yloxy)-3-phenylacrylic acid showed potential in vivo anticancer and antioxidant effects against Ehrlich ascites carcinoma cells; (EAC cells).

"RB-reactivator screening" as a novel cell-based assay for discoveries of molecular targeting agents including the first-in-class MEK inhibitor trametinib (trade name: Mekinist).

The retinoblastoma gene (RB) was discovered as the first tumor-suppressor gene. It was subsequently shown to be inactivated in most malignant tumors, particularly at the protein level. Therefore, many activated oncogenes as well as inactivated tumor-suppressor genes inactivate the function of the RB protein. I hypothesized that most of the molecular-targeting agents against activated oncogenes may reactivate the function of RB, and proposed screening systems for agents up-regulating the expression of cyclin-dependent kinase inhibitors, such as p15, p27, and p21, which convert the phosphorylated inactive form of the RB protein to the unphosphorylated active form. I termed this screening as "RB-reactivator screening". Using the screening systems for agents that up-regulate the expression of p15, p27, and p21, we discovered the novel MEK inhibitor trametinib, the novel RAF/MEK inhibitor CH5126766/RO5126766/VS-6766, and the histone deacetylase inhibitor YM753/OBP-801, respectively. Trametinib exerted remarkable effects in patients with advanced BRAF mutant melanoma, and was approved in the USA as the first-in-class MEK inhibitor (trade name: Mekinist) in 2013. The British Pharmacological Society selected trametinib as the Drug Discovery of the Year in 2013. The combination of trametinib and the BRAF inhibitor dabrafenib was approved for advanced BRAF mutant melanoma in the USA, EU, Japan, and many other countries. Additionally, the US Food and Drug Administration (FDA) granted Breakthrough Therapy Designation for the combination of trametinib and dabrafenib in the treatment of patients with advanced BRAF mutant non-small cell lung cancer in 2015, and this combination was subsequently approved in the EU, USA, and Japan. In 2018, this combination was also approved for locally advanced or metastatic BRAF V600-mutant anaplastic thyroid cancer in the USA after it had been granted Breakthrough Therapy Designation by the FDA. I describe here the characterization of our original screening system, RB-reactivator screening, by which these three molecular-targeting agents that advanced into clinical trials were identified.

Correlação entre aspectos clínicos e marcadores biológicos no processo de fotocarcinogênese de lábio / Relationship between clinical aspects and biological markers during lip photocarcinogenesis process

A queilite actínica (QA) é uma lesão potencialmente maligna importante para identificar indícios precoces de transformação maligna para o carcinoma epidermoide de lábio (CEL), possibilitando a implementação de um tratamento eficiente e menos invasivo, que promova um melhor prognóstico para os pacientes. Pesquisas recentes indicam que os métodos histopatológicos geralmente são falhos em traçar o risco de malignização de casos de QA, pois além de não demonstrar as alterações genéticas presentes nos queratinócitos, não foram realizados estudos de acompanhamento clínico para avaliar se o grau de displaia epitelial da QA está relacionado ao risco de malignização para CE. Assim, a presente pesquisa teve como objetivo caracterizar, a partir dos casos atendidos no Serviço de Patologia Cirúrgica da FOUSP, qual a diferença de perfil clínico-patológico de pacientes de QA com evolução para CEL, pacientes de QA sem informações e sinais presentes de malignização e pacientes apenas diagnosticados com CEL, e também visou analisar a expressão de Ki67 e pRb nesses três grupos. Para isso, os dados dos pacientes como idade, sexo, cor da pele, aspecto clínico da lesão fundamental, coloração, tamanho e tempo de duração das lesões foram resgatados de 998 casos e distribuídos nessas três categorias. Os resultados da análise clínico-epidemiológica revelaram que o único aspecto clínico estatisticamente significante para diferenciar pacientes apenas diagnosticados com CEL dos demais grupos foi o tempo de duração das lesões. A análise do grau de displasia epitelial nos casos de QA na amostra presente revelou que todos os pacientes de QA posteriormente diagnosticados com CEL foram classificados como lesões de alto risco, e ainda exibiram em maior frequência as atipias: aumento do número de figuras de mitose, variação anormal do tamanho do núcleo, variação anormal do tamanho da célula e alteração da relação núcleo/citoplasma, figuras de mitose anormais e aumento do número e tamanho de nucléolos. Tanto a expressão da proteína Ki-67 como da proteína pRb não demonstraram significância estatística na comparação entre os grupos do estudo. Assim, a avaliação de uma ampla série de casos revelou diferença significante no tempo de duração do CEL com relação à QA. Além disso, algumas alterações morfológicas foram observadas com maior frequência em casos de QA com evolução para CEL. No entanto, outros marcadores biológicos devem ser testados em conjunto, para tentar diagnosticar alterações precoces que levem ao desenvolvimento de CEL.

Actinic cheilitis (AC) is a potentially malignant lesion important to identify early signs of malignant transformation into lip squamous cell carcinoma (LSCC), enabling the implementation of an efficient and less invasive treatment to patients. Recent researches pointed that histopatological methods often fail to trace malignization risk in AC cases, because they are unable to identify genetic damage in keratinocytes and do not exist a clinical follow-up studie to assess if the grading of epithelial dysplasia in AC is related with the malignancy risk to LSCC development. Thus, this research aims to characterize, from cases of Surgical Pathology Service of Universidade de São Paulo, the differences in clinical and pathological profile among AC patients which had evolution to LSCC, AC patients without signs and information about malignization and patients diagnosed only with LSCC. This study also analyzed the expression of Ki-67 and pRb proteins in these three groups. To conduct this study, data as age, gender, race, fundamental lesion aspect, color, size and duration time of the lesion were collected from 998 patients. The clinical-epidemiological analysis revealed that duration time of the lesion was the statistically significant clinical feature to differentiate patients diagnosed only with LSCC from other groups. The grading of epithelial dysplasia analysis showed that all AC patients with a posterior diagnosis of LSCC were classified as high risk lesions and these cases also exhibited most frequently atypia figures as: increased number of mitotic features, abnormal variation in nuclear size, abnormal variation in cellular size, increased nuclear/cytoplasmic ratio, abnormal mitotic features and increased number and size of nucleoli. The immunohistochemical expression of both Ki-67 and pRb protein demonstrated lack of significant statistical difference among the groups. We concluded that the evaluation of a large serie of cases revealed differences in duration time of lesion in patiens only diagnoses with LSCC and some morphological criteria were most frequent in AC cases with a posterior diagnosis of LSCC. However, other biological markers must be tested together, to try to identify early steps of LSCC development.

Correlação entre aspectos clínicos e marcadores biológicos no processo de fotocarcinogênese de lábio / Relationship between clinical aspects and biological markers during lip photocarcinogenesis process

A queilite actínica (QA) é uma lesão potencialmente maligna importante para identificar indícios precoces de transformação maligna para o carcinoma epidermoide de lábio (CEL), possibilitando a implementação de um tratamento eficiente e menos invasivo, que promova um melhor prognóstico para os pacientes. Pesquisas recentes indicam que os métodos histopatológicos geralmente são falhos em traçar o risco de malignização de casos de QA, pois além de não demonstrar as alterações genéticas presentes nos queratinócitos, não foram realizados estudos de acompanhamento clínico para avaliar se o grau de displaia epitelial da QA está relacionado ao risco de malignização para CE. Assim, a presente pesquisa teve como objetivo caracterizar, a partir dos casos atendidos no Serviço de Patologia Cirúrgica da FOUSP, qual a diferença de perfil clínico-patológico de pacientes de QA com evolução para CEL, pacientes de QA sem informações e sinais presentes de malignização e pacientes apenas diagnosticados com CEL, e também visou analisar a expressão de Ki67 e pRb nesses três grupos. Para isso, os dados dos pacientes como idade, sexo, cor da pele, aspecto clínico da lesão fundamental, coloração, tamanho e tempo de duração das lesões foram resgatados de 998 casos e distribuídos nessas três categorias. Os resultados da análise clínico-epidemiológica revelaram que o único aspecto clínico estatisticamente significante para diferenciar pacientes apenas diagnosticados com CEL dos demais

grupos foi o tempo de duração das lesões. A análise do grau de displasia epitelial nos casos de QA na amostra presente revelou que todos os pacientes de QA posteriormente diagnosticados com CEL foram classificados como lesões de alto risco, e ainda exibiram em maior frequência as atipias: aumento do número de figuras de mitose, variação anormal do tamanho do núcleo, variação anormal do tamanho da célula e alteração da relação núcleo/citoplasma, figuras de mitose anormais e aumento do número e tamanho de nucléolos. Tanto a expressão da proteína Ki-67 como da proteína pRb não demonstraram significância estatística na comparação entre os grupos do estudo. Assim, a avaliação de uma ampla série de casos revelou diferença significante no tempo de duração do CEL com relação à QA. Além disso, algumas alterações morfológicas foram observadas com maior frequência em casos de QA com evolução para CEL. No entanto, outros marcadores biológicos devem ser testados em conjunto, para tentar diagnosticar alterações precoces que levem ao desenvolvimento de CEL.

Actinic cheilitis (AC) is a potentially malignant lesion important to identify early signs of malignant transformation into lip squamous cell carcinoma (LSCC), enabling the implementation of an efficient and less invasive treatment to patients. Recent researches pointed that histopatological methods often fail to trace malignization risk in AC cases, because they are unable to identify genetic damage in keratinocytes and do not exist a clinical follow-up studie to assess if the grading of epithelial dysplasia in AC is related with the malignancy risk to LSCC development. Thus, this research aims to characterize, from cases of Surgical Pathology Service of Universidade de São Paulo, the differences in clinical and pathological profile among AC patients which had evolution to LSCC, AC patients without signs and information about malignization and patients diagnosed only with LSCC. This study also analyzed the expression of Ki-67 and pRb proteins in these three groups. To conduct this study, data as age, gender, race, fundamental lesion aspect, color, size and duration time of the lesion were collected from 998 patients. The clinical-epidemiological analysis revealed that duration time of the lesion was the statistically significant clinical feature to differentiate patients diagnosed only with LSCC from other groups. The grading of epithelial dysplasia analysis showed that all AC patients with

a posterior diagnosis of LSCC were classified as high risk lesions and these cases also exhibited most frequently atypia figures as: increased number of mitotic features, abnormal variation in nuclear size, abnormal variation in cellular size, increased nuclear/cytoplasmic ratio, abnormal mitotic features and increased number and size of nucleoli. The immunohistochemical expression of both Ki-67 and pRb protein demonstrated lack of significant statistical difference among the groups. We concluded that the evaluation of a large serie of cases revealed differences in duration time of lesion in patiens only diagnoses with LSCC and some morphological criteria were most frequent in AC cases with a posterior diagnosis of LSCC. However, other biological markers must be tested together, to try to identify early steps of LSCC development.

The cooperative effect of p53 and Rb in local nanotherapy in a rabbit VX2 model of hepatocellular carcinoma.

BACKGROUND/AIM: A local nanotherapy (LNT) combining the therapeutic efficacy of trans-arterial embolization, nanoparticles, and p53 gene therapy has been previously presented. The study presented here aimed to further improve the incomplete tumor eradication and limited survival enhancement and to elucidate the molecular mechanism of the LNT. METHODS: In a tumor-targeting manner, recombinant expressing plasmids harboring wild-type p53 and Rb were either co-transferred or transferred separately to rabbit hepatic VX2 tumors in a poly-L-lysine-modified hydroxyapatite nanoparticle nanoplex and Lipiodol® (Guerbet, Villepinte, France) emulsion via the hepatic artery. Subsequent co-expression of p53 and Rb proteins within the treated tumors was investigated by Western blotting and in situ analysis by laser-scanning confocal microscopy. The therapeutic effect was evaluated by the tumor growth velocity, apoptosis and necrosis rates, their sensitivity to Adriamycin® (ADM), mitomycin C, and fluorouracil, the microvessel density of tumor tissue, and the survival time of animals. Eventually, real-time polymerase chain reaction and enhanced chemiluminescence Western blotting were used to investigate the expressive changes of important genes related to the therapy. RESULTS: The administration procedure proved safe for the rabbits' liver function, the p53 plus Rb LNT showed significantly better antitumoral effect and lower expression of malignant genes than the p53 or Rb LNT, although no significant difference was observed in animal survival when the p53 plus Rb LNT was compared with the p53 LNT. CONCLUSION: Rb works synergistically with p53 in combined therapy mediated by a poly-L-lysine-modified hydroxyapatite nanoparticle nanoplex to augment the antitumoral effect through the downregulated expression of important genes related to apoptosis, necrosis, growth, differentiation and multidrug resistance of tumor cells. LNT with p53 and Rb is potentially an effective antitumor therapy for hepatocellular carcinoma.

Retinoblastoma 94 enhances radiation treatment of esophageal squamous cell carcinoma in vitro and in vivo.

We performed the study to investigate whether adenovirus-mediated retinoblastoma 94 (RB94) gene transfer could enhance radiation treatment of esophageal squamous cell carcinoma (ESCC) in vitro and in vivo. ESCC cells (Kyse150 cell line) were cultivated in vitro and tumors originated from the cell line were propagated as xenografts in nude mice. Treatment with Ad-RB94 and/or ionizing radiation (IR) was carried out both in vitro and in vivo with Ad-LacZ control vector and blank control. Cell viability, cell cycle distribution, cell apoptosis, tumor growth and transfected gene expression were evaluated and tumor degeneration was analyzed. The data of quantification real-time PCR assays and immunohistochemistry staining using RB antibody indicated that RB94 was efficiently transfected into Kyse150 cells. In vitro, data of cell growth assay indicated that treatment with Ad-RB94 improved radiation treatment of Kyse150 cells. Tumor xenograft studies, pathological analysis of H.E. staining and Ki67 staining suggested transfecting RB94 enhanced tumor regression induced by radiation treatment in vivo. In addition, data of Annexin V, TUNEL and cell cycle distribution assays proposed combination treatment effectively induced cell apoptosis and cell cycle arresting in G2/M phase. In conclusion, transferring RB94 gene by the adenoviral vector enhances radiation treatment of ESCC.

Alterations of the retinoblastoma gene in metastatic breast cancer.

Germline mutations affecting the retinoblastoma gene (RB1) predispose to inherited retinoblastomas but also other malignancies, including breast cancer. While somatic RB1 mutations have been detected in different malignancies, information about the potential role of RB1 mutations in breast cancer is limited. Recently, we discovered RB1 mutations to be associated with resistance to anthracyclines/mitomycin in primary breast cancer. The present work is the first report evaluating RB1 mutation and epigenetic status in metastatic breast cancer. Among 148 breast cancer samples analyzed by MLPA, four samples harbored intragenic deletions/duplications: Thus, exons 1-2 were deleted in two tumors and exons 21-23 in one tumor, while one sample harbored duplication of exons 18-23. The entire RB1 gene was duplicated in two tumors and multiple amplifications were revealed in one sample. Reduced copy number was observed in 17 samples (11.5%). No point mutation or promoter hypermethylation was discovered (n = 38 and 114 tumors analyzed, respectively). Interestingly, among seven tumors expressing lack of response to epirubicin, two samples harbored alterations in RB1, contrasting none out of 16 tumors with stable disease or an objective response (P = 0.08). In summary, the frequency of RB1 alterations in metastatic lesions was not increased when compared to primary breast cancer, indicating that RB1 alterations do not play a major role in metastatic development. While a non-significant association suggesting RB1 alterations to be linked to therapy resistance was observed, our data do not suggest a major role for RB1 alterations explaining acquired drug resistance.

Search for unknown tumor-antagonizing genes.

Following the ingenious prediction of Alfred Knudson in 1971, the first tumor suppressor gene, RB1, has been isolated. Its product, the RB1 protein, was found to play a major role in the control of the cell cycle. The loss of heterozygosity (LOH) technique, introduced by Cavenee and colleagues, was an important milestone toward the confirmation of Knudson's hypothesis and the identification of the gene. Subsequently, the LOH technique has provided important clues that have led to the discovery of other tumor suppressor genes. Most of them play important roles in the regulation of the cell cycle and/or of apoptosis. Circumstantial evidence suggests that still other and perhaps many unknown genes may participate in the protection of the organism against malignant growth. The numerous genome losses in tumors, detected by LOH, comparative genomic hybridization, and by cytogenetic techniques, support this possibility. The early work of one of us (G.K.), together with Henry Harris and Francis Wiener, had shown that the malignant phenotype can be suppressed by hybridizing malignant with low- or non-tumorigenic cells. However, analysis of this phenomenon failed to assign the inhibition of tumorigenicity to any particular gene. We have pursued the search for new tumor-antagonizing genes with two unconventional approaches, focusing on human chromosomal subband 3p21.3, a region frequently targeted by cytogenetically detectable deletions. We have detected four clusters of candidate tumor suppressor genes at 3p21.3 by a combination of deletion mapping and the "elimination test." These findings raise the question whether the number and variety of genes that may contribute to the defense against uncontrolled proliferation may have been underestimated.