Improvement of gemcitabine sensitivity of p53-mutated pancreatic cancer MiaPaCa-2 cells by RUNX2 depletion-mediated augmentation of TAp73-dependent cell death

Design, Synthesis, and Antitumor Evaluation of an Opioid Growth Factor Bioconjugate Targeting Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) presents a formidable challenge with high lethality and limited effective drug treatments. Its heightened metastatic potential further complicates the prognosis. Owing to the significant toxicity of current chemotherapeutics, compounds like [Met5]-enkephalin, known as opioid growth factor (OGF), have emerged in oncology clinical trials. OGF, an endogenous peptide interacting with the OGF receptor (OGFr), plays a crucial role in inhibiting cell proliferation across various cancer types. This in vitro study explores the potential anticancer efficacy of a newly synthesized OGF bioconjugate in synergy with the classic chemotherapeutic agent, gemcitabine (OGF-Gem). The study delves into assessing the impact of the OGF-Gem conjugate on cell proliferation inhibition, cell cycle regulation, the induction of cellular senescence, and apoptosis. Furthermore, the antimetastatic potential of the OGF-Gem conjugate was demonstrated through evaluations using blood platelets and AsPC-1 cells with a light aggregometer. In summary, this article demonstrates the cytotoxic impact of the innovative OGF-Gem conjugate on pancreatic cancer cells in both 2D and 3D models. We highlight the potential of both the OGF-Gem conjugate and OGF alone in effectively inhibiting the ex vivo pancreatic tumor cell-induced platelet aggregation (TCIPA) process, a phenomenon not observed with Gem alone. Furthermore, the confirmed hemocompatibility of OGF-Gem with platelets reinforces its promising potential. We anticipate that this conjugation strategy will open avenues for the development of potent anticancer agents.

The role of diagnostic, prognostic, and predictive biomarkers in the management of early pancreatic cancer

Despite modern advances in cancer medicine, pancreatic cancer survival remains unchanged at just 12%. For the small proportion of patients diagnosed with 'early' (upfront or borderline resectable) disease, recurrences are common, and many recur soon after surgery. Whilst chemotherapy has been shown to increase survival in this cohort, the morbidity of surgery renders many candidates unsuitable for adjuvant treatment. Due to this, and the success of upfront chemotherapy in the advanced setting, use of neoadjuvant chemotherapy has been introduced in patients with upfront or borderline resectable disease. Randomized controlled trials have been conducted to compare upfront surgery to neoadjuvant chemotherapy in this patient cohort, opinions on the ideal upfront treatment approach are divided. This lack of consensus has highlighted the need for biomarkers to assist in clinical decision making. This review analyses the potential diagnostic, prognostic and predictive biomarkers that may assist in the diagnosis and management of early (upfront and borderline resectable) pancreatic cancer.

RUNX2 Reverses p53-Induced Chemotherapy Resistance in Gastric Cancer

Objective

Gastric cancer is one of the most common malignancies worldwide; however, its overall mortality has not improved significantly over the last decade. Chemoresistance plays a critical role in this issue. This study aimed to clarify the role and mechanism of runt-related transcription factor 2 (RUNX2) in platinum-based chemotherapy resistance.

Methods

First, a drug-resistant model of gastric cancer cells was established to evaluate the relative expression level of the RUNX2 as a potential biomarker of chemotherapy resistance. Next, exogenous silencing was conducted to study whether RUNX2 could reverse drug resistance and understand the underlying mechanisms. Simultaneously, the correlation between the clinical outcomes of 40 patients after chemotherapy and the RUNX2 expression levels in tumor samples was analyzed.

Results

We discovered that RUNX2 was significantly expressed in drug-resistant gastric cancer cells and tissues; it was also reversibly resistant to transformation treatment by exogenous RUNX2 silencing. It is confirmed that RUNX2 negatively regulates the apoptosis pathway of the p53 to reduce the chemotherapeutic effects of gastric cancer.

Conclusion

RUNX2 is a possible target for platinum-based chemotherapy resistance.

The RUNX Family Defines Trk Phenotype and Aggressiveness of Human Neuroblastoma through Regulation of p53 and MYCN

The Runt-related transcription factor (RUNX) family, which is essential for the differentiation of cells of neural crest origin, also plays a potential role in neuroblastoma tumorigenesis. Consecutive studies in various tumor types have demonstrated that the RUNX family can play either pro-tumorigenic or anti-tumorigenic roles in a context-dependent manner, including in response to chemotherapeutic agents. However, in primary neuroblastomas, RUNX3 acts as a tumor-suppressor, whereas RUNX1 bifunctionally regulates cell proliferation according to the characterized genetic and epigenetic backgrounds, including MYCN oncogenesis. In this review, we first highlight the current knowledge regarding the mechanism through which the RUNX family regulates the neurotrophin receptors known as the tropomyosin-related kinase (Trk) family, which are significantly associated with neuroblastoma aggressiveness. We then focus on the possible involvement of the RUNX family in functional alterations of the p53 family members that execute either tumor-suppressive or dominant-negative functions in neuroblastoma tumorigenesis. By examining the tripartite relationship between the RUNX, Trk, and p53 families, in addition to the oncogene MYCN, we endeavor to elucidate the possible contribution of the RUNX family to neuroblastoma tumorigenesis for a better understanding of potential future molecular-based therapies.

Effects of chloroquine and hydroxychloroquine on the sensitivity of pancreatic cancer cells to targeted therapies

Approaches to improve pancreatic cancer therapy are essential as this disease has a very bleak outcome. Approximately 80% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). PDAC is a cancer which is difficult to effectively treat as it is often detected late in the disease process. Almost all PDACs (over 90%) have activating mutations in the GTPase gene KRAS. These mutations result in constitutive KRas activation and the mobilization of downstream pathways such as the Raf/MEK/ERK pathway. Small molecule inhibitors of key components of the KRas/Raf/MEK/ERK pathways as well as monoclonal antibodies (MoAbs) specific for upstream growth factor receptors such insulin like growth factor-1 receptor (IGF1-R) and epidermal growth factor receptors (EGFRs) have been developed and have been evaluated in clinical trials. An additional key regulatory gene frequently mutated (∼75%) in PDAC is the TP53 tumor suppressor gene which controls the transcription of multiple genes involved in cell cycle progression, apoptosis, metabolism, cancer progression and other growth regulatory processes. Small molecule mutant TP53 reactivators have been developed which alter the structure of mutant TP53 protein and restore some of its antiproliferative activities. Some mutant TP53 reactivators have been examined in clinical trials with patients with mutant TP53 genes. Inhibitors to the TP53 negative regulator Mouse Double Minute 2 (MDM2) have been developed and analyzed in clinical trials. Chloroquine and hydroxychloroquine are established anti-malarial and anti-inflammatory drugs that also prevent the induction of autophagy which can have effects on cancer survival. Chloroquine and hydroxychloroquine have also been examined in various clinical trials. Recent studies are suggesting effective treatment of PDAC patients may require chemotherapy as well as targeting multiple pathways and biochemical processes.

A ferrocene-containing nucleoside analogue targets DNA replication in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is a disease that remains refractory to existing treatments including the nucleoside analogue gemcitabine. In the current study we demonstrate that an organometallic nucleoside analogue, the ferronucleoside 1-(S,Rp), is cytotoxic in a panel of PDAC cell lines including gemcitabine-resistant MIAPaCa2, with IC50 values comparable to cisplatin. Biochemical studies show that the mechanism of action is inhibition of DNA replication, S-phase cell cycle arrest and stalling of DNA-replication forks, which were directly observed at single molecule resolution by DNA-fibre fluorography. In agreement with this, transcriptional changes following treatment with 1-(S,Rp) include activation of three of the four genes (HUS1, RAD1, RAD17) of the 9-1-1 check point complex clamp and two of the three genes (MRE11, NBN) that form the MRN complex as well as activation of multiple downstream targets. Furthermore, there was evidence of phosphorylation of checkpoint kinases 1 and 2 as well as RPA1 and gamma H2AX, all of which are considered biochemical markers of replication stress. Studies in p53-deficient cell lines showed activation of CDKN1A (p21) and GADD45A by 1-(S,Rp) was at least partially independent of p53. In conclusion, because of its potency and activity in gemcitabine-resistant cells, 1-(S,Rp) is a promising candidate molecule for development of new treatments for PDAC.

The potential roles of p53 signaling reactivation in pancreatic cancer therapy

Globally, pancreatic cancer (PC) is a common and highly malignant gastrointestinal tumor that is characterized by an insidious onset and ready metastasis and recurrence. Over recent decades, the incidence of PC has been increasing on an annual basis; however, the pathogenesis of this condition remains enigmatic. PC is not sensitive to radio- or chemotherapy, and except for early surgical resection, there is no curative treatment regime; consequently, the prognosis for patients with PC is extremely poor. Transcription factor p53 is known to play key roles in many important biological processes in vertebrates, including normal cell growth, differentiation, cell cycle progression, senescence, apoptosis, metabolism, and DNA damage repair. However, there is a significant paucity of basic and clinical studies to describe how p53 gene mutations or protein dysfunction facilitate the occurrence, progression, invasion, and resistance to therapy, of malignancies, including PC. Herein, we describe the involvement of p53 signaling reactivation in PC treatment as well as its underlying molecular mechanisms, thereby providing useful insights for targeting p53-related signal pathways in PC therapy.

Modified Gold Nanoparticles to Overcome the Chemoresistance to Gemcitabine in Mutant p53 Cancer Cells

Mutant p53 proteins result from missense mutations in the TP53 gene, the most mutated in human cancer, and have been described to contribute to cancer initiation and progression. Therapeutic strategies for targeting mutant p53 proteins in cancer cells are limited and have proved unsuitable for clinical application due to problems related to drug delivery and toxicity to healthy tissues. Therefore, the discovery of efficient and safe therapeutic strategies that specifically target mutant p53 remains challenging. In this study, we generated gold nanoparticles (AuNPs) chemically modified with low molecular branched polyethylenimine (bPEI) for the efficient delivery of gapmers targeting p53 mutant protein. The AuNPs formulation consists of a combination of polymeric mixed layer of polyethylene glycol (PEG) and PEI, and layer-by-layer assembly of bPEI through a sensitive linker. These nanoparticles can bind oligonucleotides through electrostatic interactions and release them in the presence of a reducing agent as glutathione. The nanostructures generated here provide a non-toxic and powerful system for the delivery of gapmers in cancer cells, which significantly downregulated mutant p53 proteins and altered molecular markers related to cell growth and apoptosis, thus overcoming chemoresistance to gemcitabine.

Effects of the MDM2 inhibitor Nutlin-3a on sensitivity of pancreatic cancer cells to berberine and modified berberines in the presence and absence of WT-TP53

Approaches to improve pancreatic cancer therapy are essential as this disease has a very bleak outcome. Approximately 80% of pancreatic cancers are pancreatic ductal adenocarcinomas (PDAC). A key regulatory gene frequently mutated (∼75%) in PDAC is the TP53 tumor suppressor gene which controls the transcription of multiple genes involved in cell cycle progression, apoptosis, cancer progression and other growth regulatory processes. The mouse double minute 2 homolog (MDM2) gene product is a nuclear-localized E3 ubiquitin ligase and negatively regulates the TP53 protein which results in its proteasomal degradation. Various MDM2 inhibitors have been isolated and examined in clinical trials, especially in patients with hematological malignancies. Nutlin-3a is one of the first MDM2 inhibitors isolated. Berberine (BBR) is a natural product found in many fruits and berries and used in traditional medicine for centuries. It has many biological effects, and some are anti-proliferative in nature. BBR may activate the expression of TP53 and inhibit cell cycle progression as well as other events important in cell growth. To understand more about the potential of compounds like BBR and chemical modified BBRs (NAX compounds) to sensitize PDAC cells to MDM2 inhibitors, we introduced either WT-TP53 or the pLXSN empty vector control into two PDAC cell lines, one lacking expression of TP53 (PANC-28) and one with gain-of-function mutant TP53 on both alleles (MIA-PaCa-2). Our results indicate that nutlin-3a was able to increase the sensitivity to BBR and certain NAX compounds. The effects of nutlin-3a were usually more substantial in those cells containing an introduced WT TP53 gene. These results highlight the importance of knowledge of the type of TP53 mutation that is present in cancer patients before the administration of drugs which function by stabilization of the TP53 protein.

Cancer cells escape autophagy inhibition via NRF2-induced macropinocytosis

Many cancers, including pancreatic ductal adenocarcinoma (PDAC), depend on autophagy-mediated scavenging and recycling of intracellular macromolecules, suggesting that autophagy blockade should cause tumor starvation and regression. However, until now autophagy-inhibiting monotherapies have not demonstrated potent anti-cancer activity. We now show that autophagy blockade prompts established PDAC to upregulate and utilize an alternative nutrient procurement pathway: macropinocytosis (MP) that allows tumor cells to extract nutrients from extracellular sources and use them for energy generation. The autophagy to MP switch, which may be evolutionarily conserved and not cancer cell restricted, depends on activation of transcription factor NRF2 by the autophagy adaptor p62/SQSTM1. NRF2 activation by oncogenic mutations, hypoxia, and oxidative stress also results in MP upregulation. Inhibition of MP in autophagy-compromised PDAC elicits dramatic metabolic decline and regression of transplanted and autochthonous tumors, suggesting the therapeutic promise of combining autophagy and MP inhibitors in the clinic.

The COL11A1/Akt/CREB signaling axis enables mitochondrial-mediated apoptotic evasion to promote chemoresistance in pancreatic cancer cells through modulating BAX/BCL-2 function

Collagen XI, a member of the collagen family, is present in the extracellular matrix (ECM), and high collagen XI/αI (COL11A1) expression in tumor tissue is reportedly correlated with the clinicopathological parameters of pancreatic ductal adenocarcinoma (PDAC). However, the function of COL11A1 in the development of pancreatic cancer cells remains unclear. In the current study, we assessed mRNA expression of COL11A1 and its receptors and created a testing-model of both a COL11A1-overexpressing tumor microenvironment and/or altered-COL11A1 expression in pancreatic cancer cell lines. Next, we investigated the mechanism by which COL11A1 affects growth, gemcitabine (GEM) resistance and apoptosis in pancreatic cancer cells. We demonstrated that COL11A1 phosphorylated Akt^Ser473, promoting proliferation of cancer cells and inhibiting their apoptosis. Additionally, our data showed that COL11A1/Akt/CREB altered the balance between BCL-2 and BAX and mediated their mitochondrial translocation in pancreatic cancer cells. The COL11A1/Akt axis induced disruption of mitochondrial transmembrane function, enabling mitochondria-mediated apoptotic evasion to promote chemoresistance. We also explored the regulatory effect of COL11A1/Akt on molecular signaling in the mitochondria-mediated apoptotic program. COL11A1/Akt disturbed the BCL-2/BAX balance, inhibiting cytochrome c (Cyt-C) release and binding of Apaf-1/procaspase-9/Cyt-C, which suppressed the apoptotic program and induced GEM resistance in pancreatic cancer cells. In conclusion, COL11A1 modulates apoptotic inhibition and chemoresistance in pancreatic cancer cells by activating the Akt/CREB/BCL-2/BAX signaling pathway. COL11A1 may represent a distinct prognostic indicator and may be an attractive therapeutic target for PDAC.

Inhibition of LINC00994 represses malignant behaviors of pancreatic cancer cells: interacting with miR-765-3p/RUNX2 axis

Pancreatic cancer exhibits one of the worst prognosis of all human cancers, and it is associated with gene dysregulation. Our microarray results first indicated long intergenic non-protein coding RNA 994 (LINC00994) as an upregulated long non-coding RNA (lncRNA) and miR-765-3p as a downregulated microRNA (miRNA) in pancreatic cancer tissues (Fold change ≥ 2 and P < 0.05; three paired samples). To investigate the role of LINC00994 in pancreatic carcinogenesis, a pair of short hairpin RNA (shRNA) was used to stably knock down the endogenous expression of LINC00994 in Panc-1 and AsPC-1 pancreatic cancer cells in vitro. We found that LINC00994 silencing inhibited the growth, migration and invasion, and promoted the G1 cell cycle arrest and apoptosis in Panc-1 and AsPC-1 cells. Furthermore, the expression of LINC00994 was negatively correlated with that of miR-765-3p in 10 pancreatic cancer specimens. Runt-related transcription factor 2 (RUNX2), a molecule that contributes to the aggressive behaviors of pancreatic cancer, was herein verified as a novel target for miR-765-3p. Like LINC00994, its expression was elevated in pancreatic cancers. Silencing of LINC00994 and RUNX2 reduced each other's expression in both Panc-1 and AsPC-1 cells. RUNX2 3'UTR and LINC00994 competed to bind miR-765-3p. Additionally, LINC00994-silenced cells regained their aggressive behaviors when miR-765-3p was antagonized, which was accompanied with RUNX2 re-expression. Collectively, our study reveals that LINC00994 contributes to the malignant behaviors of pancreatic cancer cells by preventing miR-765-3p from targeting RUNX2. LINC00994 can be considered as a novel therapeutic target against pancreatic cancer.

Impact of RUNX2 on drug-resistant human pancreatic cancer cells with p53 mutations

Background

Despite the remarkable advances in the early diagnosis and treatment, overall 5-year survival rate of patients with pancreatic cancer is less than 10%. Gemcitabine (GEM), a cytidine nucleoside analogue and ribonucleotide reductase inhibitor, is a primary option for patients with advanced pancreatic cancer; however, its clinical efficacy is extremely limited. This unfavorable clinical outcome of pancreatic cancer patients is at least in part attributable to their poor response to anti-cancer drugs such as GEM. Thus, it is urgent to understand the precise molecular basis behind the drug-resistant property of pancreatic cancer and also to develop a novel strategy to overcome this deadly disease.

Review

Accumulating evidence strongly suggests that p53 mutations contribute to the acquisition and/or maintenance of drug-resistant property of pancreatic cancer. Indeed, certain p53 mutants render pancreatic cancer cells much more resistant to GEM, implying that p53 mutation is one of the critical determinants of GEM sensitivity. Intriguingly, runt-related transcription factor 2 (RUNX2) is expressed at higher level in numerous human cancers such as pancreatic cancer and osteosarcoma, indicating that, in addition to its pro-osteogenic role, RUNX2 has a pro-oncogenic potential. Moreover, a growing body of evidence implies that a variety of miRNAs suppress malignant phenotypes of pancreatic cancer cells including drug resistance through the down-regulation of RUNX2. Recently, we have found for the first time that forced depletion of RUNX2 significantly increases GEM sensitivity of p53-null as well as p53-mutated pancreatic cancer cells through the stimulation of p53 family TAp63/TAp73-dependent cell death pathway.

Conclusions

Together, it is likely that RUNX2 is one of the promising molecular targets for the treatment of the patients with pancreatic cancer regardless of their p53 status. In this review article, we will discuss how to overcome the serious drug-resistant phenotype of pancreatic cancer.

Depletion of runt-related transcription factor 2 (RUNX2) enhances SAHA sensitivity of p53-mutated pancreatic cancer cells through the regulation of mutant p53 and TAp63

Suberoylanilide hydroxamic acid (SAHA) represents one of the new class of anti-cancer drugs. However, multiple lines of clinical evidence indicate that SAHA might be sometimes ineffective on certain solid tumors including pancreatic cancer. In this study, we have found for the first time that RUNX2/mutant p53/TAp63-regulatory axis has a pivotal role in the determination of SAHA sensitivity of p53-mutated pancreatic cancer MiaPaCa-2 cells. According to our present results, MiaPaCa-2 cells responded poorly to SAHA. Forced depletion of mutant p53 stimulated SAHA-mediated cell death of MiaPaCa-2 cells, which was accomapanied by a further accumulation of γH2AX and cleaved PARP. Under these experimental conditions, pro-oncogenic RUNX2 was strongly down-regulated in mutant p53-depleted MiaPaCa-2 cells. Surprisingly, RUNX2 silencing augmented SAHA-dependent cell death of MiaPaCa-2 cells and caused a significant reduction of mutant p53. Consistent with these observations, overexpression of RUNX2 in MiaPaCa-2 cells restored SAHA-mediated decrease in cell viability and increased the amount of mutant p53. Thus, it is suggestive that there exists a positive auto-regulatory loop between RUNX2 and mutant p53, which might amplify their pro-oncogenic signals. Intriguingly, knockdown of mutant p53 or RUNX2 potentiated SAHA-induced up-regulation of TAp63. Indeed, SAHA-stimulated cell death of MiaPaCa-2 cells was partially attenuated by p63 depletion. Collectively, our present observations strongly suggest that RUNX2/mutant p53/TAp63-regulatory axis is one of the key determinants of SAHA sensitivity of p53-mutated pancreatic cancer cells.

The anti-tumor effects of the recombinant toxin protein rLj-RGD3 from Lampetra japonica on pancreatic carcinoma Panc-1 cells in nude mice

Recombinant Lampetra japonica RGD peptide (rLj-RGD3) is a soluble toxin protein with three RGD (Arg-Gly-Asp) motifs and a molecular weight of 13.5kDa. The aim of this study was to investigate the effects and mechanisms of rLj-RGD3 on tumor growth and survival in pancreatic carcinoma Panc-1 cell-bearing mice. A Panc-1 human pancreatic carcinoma-bearing nude mouse model was successfully generated, and the animals were treated with different doses of rLj-RGD3 for 3 weeks. The volume and weight of the subcutaneous tumors, the survival of the nude mice, histopathological changes, the intratumoral MVD, the number of apoptotic Panc-1 cells, and apoptosis-related proteins and gene expressions were determined. rLj-RGD3 significantly decreased the tumor volumes and weights, and the maximum tumor volume and weight IR values were 53.2% (p<0.001) and 55.9% (p<0.001), respectively. The life expectancy of Panc-1-bearing nude mice treated with rLj-RGD3 was increased by 56.3% (p<0.001). Meanwhile, rLj-RGD3 promoted the expression of Bax, caspase-3, and caspase-9 and inhibited Bcl-2 and VEGF expression. In addition, rLj-RGD3 did not change FAK, PI3K and Akt expression, but p-FAK, p-PI3K and p-Akt, levels were down-regulated. These results show that rLj-RGD3 induced potent anti-tumor activity in vivo and suppressed the growth of transplanted Panc-1 cells in a nude mouse model, implying that rLj-RGD3 may serve as a potent clinical therapeutic agent for human pancreatic carcinoma.